Volume 6 Electrical Equipment (Issuing Version of 27-01-2011)(1)

Socialist Republic of Vietnam

EEVVNN

Vietnam Electricity

NNBBTTPPCC

Ninh Binh Thermal Power Joint Stock Company

THAI BINH THERMAL POWER PLANT TWO (2) X 300 MW Thai Binh Province

BIDDING DOCUMENT

Volume 6 of 12

Electrical Equipment

OWNER CONSULTANT

VIETNAM ELECTRICITY 18 Tran Nguyen Han Street

Hanoi, Vietnam

FICHTNER GmbH & Co KG in association with

TEPSCO and PECC1

JANUARY 2011

THAI BINH THERMAL POWER PLANT PROJECT 2X300 MW VOLUME 6

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Table of Content

6 ELECTRICAL EQUIPMENT ...................................................... 9

6.1 GENERAL ..................................................................................................... 9

6.2 GENERATORS AND AUXILIARIES ...................................................... 10

6.2.1 GENERATOR DESIGN ...................................................................................................... 10 6.2.1.1 Rating ........................................................................................................................... 10 6.2.1.2 Characteristics .............................................................................................................. 10 6.2.1.3 Voltage and Frequency ................................................................................................ 10

6.2.2 STATOR ........................................................................................................................... 11 6.2.2.1 Casing .......................................................................................................................... 11 6.2.2.2 Core .............................................................................................................................. 11 6.2.2.3 Winding........................................................................................................................ 11 6.2.2.4 Terminals ..................................................................................................................... 12 6.2.2.5 Connection to Busbars and Earthing Transformer ....................................................... 12

6.2.3 ROTOR............................................................................................................................. 12 6.2.3.1 Winding........................................................................................................................ 12 6.2.3.2 Shaft ............................................................................................................................. 13 6.2.3.3 Slip Rings ..................................................................................................................... 13

6.2.4 GENERATOR EARTHING ................................................................................................. 13 6.2.4.1 Neutral Point ................................................................................................................ 13 6.2.4.2 Casing .......................................................................................................................... 13 6.2.4.3 Turbine/Generator Shaft Voltage/Current Control ...................................................... 14

6.2.5 GENERATOR CONDITION MONITORING ........................................................................ 15 6.2.5.1 Core Monitor ................................................................................................................ 15 6.2.5.2 Rotor Shorted Turns Detection Coil ............................................................................ 15 6.2.5.3 End Winding Vibration Sensors .................................................................................. 15 6.2.5.4 High Speed Electronic Fault Recorder ........................................................................ 15 6.2.5.5 Partial Discharge Monitoring ....................................................................................... 15

6.2.6 GENERATOR EXCITATION .............................................................................................. 15 6.2.6.1 General ......................................................................................................................... 15 6.2.6.2 Performance ................................................................................................................. 16 6.2.6.3 Static Thyristors Excitation System ............................................................................. 17 6.2.6.4 Supervision .................................................................................................................. 18

6.2.7 EXCITATION CONTROL SYSTEM .................................................................................... 18 6.2.7.1 Construction and Reliability ........................................................................................ 18 6.2.7.2 Characteristics .............................................................................................................. 20 6.2.7.3 Supplementary Controls............................................................................................... 20 6.2.7.4 Supplementary Protection ............................................................................................ 23 6.2.7.5 Manual Excitation Control ........................................................................................... 23 6.2.7.6 Test Facilities ............................................................................................................... 24 6.2.7.7 Sources for Generator Voltage Signals ........................................................................ 25 6.2.7.8 Performance Data ......................................................................................................... 25


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6.2.8 GENERATOR COOLING ................................................................................................... 25 6.2.8.1 Hydrogen Cooling System ........................................................................................... 26 6.2.8.2 Generator Cooling Board ............................................................................................. 27

6.2.9 HYDROGEN SEALS AND SEAL OIL SYSTEM ................................................................... 27

6.2.10 GENERATOR CASING PURGING SYSTEM ..................................................................... 28

6.2.11 TEMPERATURE MEASUREMENT ................................................................................... 28

6.2.12 GENERATOR CURRENT AND VOLTAGE TRANSFORMERS ............................................ 29

6.2.13 GENERATOR FIRE PROTECTION .................................................................................. 29

6.3 AC AUXILIARY SYSTEM ........................................................................ 30

6.3.1 SYSTEM DESCRIPTION .................................................................................................... 30 6.3.1.1 General Technical Requirements ................................................................................. 31 6.3.1.2 Generator Circuit Breaker Scheme .............................................................................. 32 6.3.1.3 Loadings and Transformer Ratings .............................................................................. 33 6.3.1.4 System Configuration Interlocking .............................................................................. 35 6.3.1.5 Automatic Switching ................................................................................................... 36 6.3.1.6 Circuit Allocations ....................................................................................................... 36 6.3.1.7 Load Identification and Measurement ......................................................................... 37 6.3.1.8 Fault Levels .................................................................................................................. 37 6.3.1.9 Voltage Distribution and Regulation ........................................................................... 37

6.3.2 TRANSFORMERS .............................................................................................................. 38 6.3.2.1 220/19kV Generator Transformer................................................................................ 38 6.3.2.2 19/6.6-6.6kV Unit Transformers.................................................................................. 39 6.3.2.3 220/6.6-6.6kV Station Transformer ............................................................................. 40 6.3.2.4 6.6kV/400V Unit Auxiliary Transformers & Station Auxiliary Transformers ........... 40 6.3.2.5 6.6kV/400V Emergency Transformes ......................................................................... 41

6.3.3 SWITCHGEAR .................................................................................................................. 42 6.3.3.1 General ......................................................................................................................... 42 6.3.3.2 Medium Voltage Switchboards (6.6kV) ...................................................................... 42 6.3.3.3 Low Voltage Switchboards (400V) ............................................................................. 44 6.3.3.4 Drawings and Design Documents ................................................................................ 45

6.3.4 ELECTRICAL PROTECTION AND METERING .................................................................. 46 6.3.4.1 General ......................................................................................................................... 46 6.3.4.2 Design Criteria for Generator Protection Scheme ....................................................... 50 6.3.4.3 Design Criteria for 220/6.6-6.6kV Station Transformer Protection ............................ 54 6.3.4.4 Design Criteria for 6.6kV Distribution System (Unit Auxiliary and Station) ............. 55 6.3.4.5 Design Criteria for 400V Distribution System (Unit Auxiliary, Emergency, Station Auxiliary) ................................................................................................................................. 56 6.3.4.6 Design Criteria for 400V MCCs (Unit Auxiliary and Station Auxiliary Services) ..... 57 6.3.4.7 Drawings and design data ............................................................................................ 57 6.3.4.8 Electrical Synchronizing Facilities .............................................................................. 58

6.3.5 CABLING WORKS AND MISCELLANEOUS REQUIREMENTS ........................................... 59 6.3.5.1 General ......................................................................................................................... 59 6.3.5.2 Information to be provided .......................................................................................... 60


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6.4 DC SYSTEM ................................................................................................ 61

6.4.1 GENERAL ........................................................................................................................ 61

6.4.2 BATTERIES, CHARGERS, INVERTERS AND UPS MODULES ............................................ 62

6.4.3 REQUIREMENTS FOR BATTERY ROOMS ......................................................................... 63

6.4.4 BATTERY INSTALLATION SAFETY REQUIREMENTS ...................................................... 63

6.4.5 DRAWINGS TO BE PROVIDED BY THE CONTRACTOR ..................................................... 64

6.5 ELECTRICAL PLANT .............................................................................. 65

6.5.1 PHASE ISOLATED BUSBAR (PIB) SYSTEMS .................................................................... 65 6.5.1.1 Extent of Supply .......................................................................................................... 66 6.5.1.2 Busbars ......................................................................................................................... 66 6.5.1.3 Electrical Characteristics ............................................................................................. 67 6.5.1.4 Construction ................................................................................................................. 67 6.5.1.5 Ductwork...................................................................................................................... 68 6.5.1.6 Aluminium Welding .................................................................................................... 69 6.5.1.7 Support Structures, Framework and Brackets ............................................................. 69 6.5.1.8 Busbar Support Insulators ............................................................................................ 69 6.5.1.9 Dished Spring ("Belleville") Washers ......................................................................... 69 6.5.1.10 Current Transformers ................................................................................................. 70 6.5.1.11 Voltage Transformers ................................................................................................ 70 6.5.1.12 Generator Neutral Earthing Transformers ................................................................. 72 6.5.1.13 Earthing Resistors ...................................................................................................... 72 6.5.1.14 CT/VT Marshalling Cubicles ..................................................................................... 73 6.5.1.15 Magnetic Screens ....................................................................................................... 73 6.5.1.16 Earthing Switches ...................................................................................................... 74

6.5.2 GENERATOR CIRCUIT BREAKER .................................................................................... 75 6.5.2.1 Circuit Breaker, Isolator and Grounding Switches - General Description .................. 75 6.5.2.2 Circuit Breaker Operating Mechanism ........................................................................ 76 6.5.2.3 Trip Coils ..................................................................................................................... 77 6.5.2.4 Closing Coil ................................................................................................................. 77 6.5.2.5 Isolating Switch Operating Mechanism ....................................................................... 77 6.5.2.6 Grounding Switch Operating Mechanism ................................................................... 77 6.5.2.7 Essential requirements ................................................................................................. 78 6.5.2.8 General Design Considerations.................................................................................... 79 6.5.2.9 Control Philosophy ...................................................................................................... 80 6.5.2.10 Circuit Breaker Control Cubicle ................................................................................ 80

6.5.3 DIESEL GENERATOR ....................................................................................................... 80 6.5.3.1 General ......................................................................................................................... 80 6.5.3.2 Type of Plant ................................................................................................................ 81 6.5.3.3 Design and Selection.................................................................................................... 81 6.5.3.4 Rating of Plant ............................................................................................................. 81 6.5.3.5 Operating Philosophy................................................................................................... 82 6.5.3.6 In Service Testing ........................................................................................................ 83 6.5.3.7 D.C. Auxiliaries for the Diesel Generators .................................................................. 83 6.5.3.8 Extent of Supply .......................................................................................................... 84


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6.5.3.9 Particulars of Plant ....................................................................................................... 85

6.6 HIGH VOLTAGE SWITCHYARD ........................................................ 100

6.6.1 GENERAL ...................................................................................................................... 100 6.6.1.1 Scope of Works .......................................................................................................... 100 6.6.1.2 Design Parameters ..................................................................................................... 101 6.6.1.3 Insulation Co-ordination ............................................................................................ 103 6.6.1.4 Training ...................................................................................................................... 105

6.6.2 SWITCHGEAR ................................................................................................................ 105 6.6.2.1 General ....................................................................................................................... 105 6.6.2.2 Circuit Breakers ......................................................................................................... 109 6.6.2.3 Current Transformers ................................................................................................. 110 6.6.2.4 Voltage Transformers ................................................................................................ 112 6.6.2.5 Disconnectors and Earth Switches ............................................................................. 113 6.6.2.6 Insulators .................................................................................................................... 115 6.6.2.7 Surge Arresters........................................................................................................... 115 6.6.2.8 Tariff Metering........................................................................................................... 117 6.6.2.9 Conductors and Busbars ............................................................................................ 117

6.6.3 TECHNICAL SERVICE .................................................................................................... 117 6.6.3.1 Protection Systems ..................................................................................................... 117 6.6.3.2 Protection Policy ........................................................................................................ 118 6.6.3.3 General Specification for Protection Equipment ....................................................... 119 6.6.3.4 Specific Requirements for Protection Equipment ...................................................... 120 6.6.3.5 Distance Protection for 220kV Transmission Lines .................................................. 121 6.6.3.6 Busbar Protection ....................................................................................................... 121

6.6.4 EQUIPMENT LAYOUT IN THE SWITCHYARD .................................................................. 122 6.6.4.1 220kV Equipment ...................................................................................................... 122

6.6.5 MEASUREMENT, CONTROL AND PROTECTION SYSTEM ............................................... 122 6.6.5.1 General ....................................................................................................................... 122 6.6.5.2 Switchyard control system ......................................................................................... 122 6.6.5.3 Protection - Automatic equipment ............................................................................. 127

6.6.6 AUXILIARY SYSTEMS .................................................................................................... 129 6.6.6.1 AC - DC auxiliary power sources .............................................................................. 129 6.6.6.2 Charger ....................................................................................................................... 130 6.6.6.3 Battery ........................................................................................................................ 130

6.6.7 LIGHTNING PROTECTION SYSTEM ............................................................................... 130

6.6.8 ELECTRICAL WORKS ................................................................................................... 130 6.6.8.1 Extent of Work ........................................................................................................... 130 6.6.8.2 General Specification ................................................................................................. 131 6.6.8.3 Busbars and Connections ........................................................................................... 132 6.6.8.4 Kiosks ........................................................................................................................ 134 6.6.8.5 L.V. Cabling............................................................................................................... 134 6.6.8.6 Earthing System ......................................................................................................... 136 6.6.8.7 Switchyard Lighting................................................................................................... 137 6.6.8.8 L.V. AC Switchyard Power Outlets ........................................................................... 137


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6.6.8.9 Building Equipment ................................................................................................... 138 6.6.8.10 220V DC Distribution Boards ................................................................................. 138 6.6.8.11 400/230V AC Distribution Boards .......................................................................... 138

6.7 COMMUNICATION SYSTEMS ............................................................ 140

6.7.1 SCOPE OF SUPPLY ......................................................................................................... 140 6.7.1.1 SDH (Synchronous Digital Hierarchy) telecommunication system for connecting the Project to the national power network. .................................................................................. 140 6.7.1.2 Inside-Plant Communications System ....................................................................... 140

6.7.2 EQUIPMENT OPERATING CONDITIONS ........................................................................ 141 6.7.2.1 Operating Conditions ................................................................................................. 141 6.7.2.2 Equipment Racks and Cubicles ................................................................................. 142 6.7.2.3 Equipment Alarms ..................................................................................................... 142 6.7.2.4 Communication Room Facilities ............................................................................... 142 6.7.2.5 Grounding for telecommunication equipment ........................................................... 144 6.7.2.6 Lightning resistance ................................................................................................... 144

6.7.3 SDH TELECOMMUNICATION SYSTEM ......................................................................... 145 6.7.3.1 Overview .................................................................................................................... 145 6.7.3.2 Optical Fibres and Accessories .................................................................................. 145 6.7.3.3 Equipment .................................................................................................................. 147 6.7.3.4 PCM Multiplexer ....................................................................................................... 148 6.7.3.5 Teleprotection ............................................................................................................ 148 6.7.3.6 Rack 19” Type ........................................................................................................... 149 6.7.3.7 DDF/MDF Cubicle .................................................................................................... 149 6.7.3.8 Modem ....................................................................................................................... 149 6.7.3.9 Power Supply ............................................................................................................. 150

6.7.4 PRIVATE AUTOMATIC BRANCH EXCHANGE (PABX) SYSTEM ................................... 152 6.7.4.1 Scope of Supply ......................................................................................................... 152 6.7.4.2 Particular Requirements of Main PABX ................................................................... 152 6.7.4.3 Console Table ............................................................................................................ 153 6.7.4.4 Subscriber Network ................................................................................................... 153 6.7.4.5 Back-up PABX .......................................................................................................... 153 6.7.4.6 Telephones (Main and Back-up) ................................................................................ 154 6.7.4.7 Telephones Cable ....................................................................................................... 154 6.7.4.8 Intermediate Distribution Frames (IDFs) and Final Distribution Points (FDPs) ....... 154 6.7.4.9 Telephones Sockets .................................................................................................... 154 6.7.4.10 Location of Telephones............................................................................................ 155

6.7.5 PUBLIC ADDRESS SYSTEM (PA SYSTEM) ..................................................................... 155 6.7.5.1 Scope of Supply ......................................................................................................... 155 6.7.5.2 Technical Requirement .............................................................................................. 156 6.7.5.3 Location of Loudspeakers .......................................................................................... 157

6.7.6 SUPERVISION CAMERA SYSTEM ................................................................................... 157

6.7.7 UHF SYSTEMS .............................................................................................................. 157 6.7.7.1 Two-Way Radio System ............................................................................................ 157 6.7.7.2 Pager System .............................................................................................................. 158


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6.7.8 LOCAL AREA NETWORK .............................................................................................. 159

6.7.9 INSTALLATION AND CABLING ...................................................................................... 160 6.7.9.1 Power Cables ............................................................................................................. 160 6.7.9.2 Miscellaneous Equipment Racks ............................................................................... 160 6.7.9.3 Other Equipment ........................................................................................................ 160

6.8 TEST AND INSPECTION ....................................................................... 161

6.8.1 APPLICATION ................................................................................................................ 161

6.8.2 GENERATOR .................................................................................................................. 161 6.8.2.1 Test and Inspection at Workshop ............................................................................... 161 6.8.2.2 Test and Inspection at Site ......................................................................................... 163

6.8.3 EXCITATION SYSTEM ................................................................................................... 164 6.8.3.1 Test and Inspection at workshop ................................................................................ 164 6.8.3.2 Test and Inspection at Site ......................................................................................... 165

6.8.4 AC AUXILIARY SYSTEM ............................................................................................... 166 6.8.4.1 Unit Load Power Consumption ................................................................................. 166 6.8.4.2 Transformers .............................................................................................................. 166 6.8.4.3 Switchgear.................................................................................................................. 168 6.8.4.4 Electrical Protection and Metering ............................................................................ 169

6.8.5 CABLING, WIRING AND TERMINALS ............................................................................ 169

6.8.6 EARTHING AND LIGHTNING PROTECTION ................................................................... 170

6.8.7 MISCELLANEOUS POWER AND LIGHTING ................................................................... 170

6.8.8 DC AUXILIARY SYSTEM ............................................................................................... 170

6.8.9 PHASE ISOLATED BUSBARS .......................................................................................... 170 6.8.9.1 Busbar Assemblies ..................................................................................................... 170 6.8.9.2 Current Transformers ................................................................................................. 171 6.8.9.3 Distribution Type Earthing Transformers .................................................................. 171 6.8.9.4 Neutral Earthing Resistor Tests ................................................................................. 171 6.8.9.5 Earthing Switches ...................................................................................................... 172 6.8.9.6 Aluminium Welds ...................................................................................................... 172 6.8.9.7 Temperature Rise of Busbars and Evaluation of Losses ........................................... 172 6.8.9.8 Aluminium Welding Tests ......................................................................................... 175

6.8.10 GENERATOR CIRCUIT BREAKERS .............................................................................. 176 6.8.10.1 Subcontractors .......................................................................................................... 176 6.8.10.2 Complete Circuit Breakers - Design Tests ............................................................... 176 6.8.10.3 Complete Circuit Breakers - Production Tests ........................................................ 176 6.8.10.4 Tests at Site .............................................................................................................. 176

6.8.11 DIESEL GENERATORS ................................................................................................. 177 6.8.11.1 Works Tests ............................................................................................................. 177 6.8.11.2 Site Tests .................................................................................................................. 177 6.8.11.3 Commissioning Tests ............................................................................................... 178

6.8.12 HIGH VOLTAGE SWITCHYARD SYSTEM ...................................................................... 178 6.8.12.1 Test and Commissioning.......................................................................................... 178


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6.8.12.2 Pre-commissioning Tests ......................................................................................... 178 6.8.12.3 Commissioning Tests ............................................................................................... 179

6.8.13 COMMUNICATION SYSTEM ......................................................................................... 179 6.8.13.1 Factory Tests ............................................................................................................ 179 6.8.13.2 Type Tests ................................................................................................................ 179 6.8.13.3 Routine Tests ........................................................................................................... 180 6.8.13.4 Site Tests .................................................................................................................. 181 6.8.13.5 Power Supply ........................................................................................................... 181 6.8.13.6 Alarm Panel ............................................................................................................. 181 6.8.13.7 Exchanges and Telephones ...................................................................................... 181 6.8.13.8 30 Day Test .............................................................................................................. 181

6.9 COAL HANDLING PLANT ............................................................................ 182

6.9.1 LOW VOLTAGE SWITCHBOARDS AND SWITCHGEAR ................................................... 182

6.9.2 ELECTRICAL FIELD DEVICES - SAFETY AND CONTROL .............................................. 182 6.9.2.1 General ....................................................................................................................... 182 6.9.2.2 Enclosures .................................................................................................................. 182 6.9.2.3 Limit Switches ........................................................................................................... 182 6.9.2.4 Tail Pulley Coal Build-up Switches ........................................................................... 182 6.9.2.5 Belt Tracking Switches .............................................................................................. 182 6.9.2.6 Emergency Stop Switches .......................................................................................... 182 6.9.2.7 Ultrasonics ................................................................................................................. 183

6.9.3 ELECTRICAL PROTECTION EQUIPMENT ...................................................................... 183

6.9.4 LOCAL CONTROL STATIONS ........................................................................................ 183

6.9.5 ACTUATORS FOR RETRACTABLE SKIRTS, GATES, SWING CHUTES, SHUTTLE HEADS

................................................................................................................................................ 183

6.9.6 MOTORS ........................................................................................................................ 184

6.9.7 SWITCH ROOM VENTILATION PLANT .......................................................................... 184

6.9.8 SWITCH ROOM LAYOUT ............................................................................................... 185

6.9.9 CABLING ....................................................................................................................... 186

6.9.10 CONTROL SYSTEM ...................................................................................................... 186

6.9.11 STACKER, RECLAIMER AND STACKER/RECLAIMER - ELECTRICAL ......................... 186

6.9.12 SHIP/BARGE UNLOADER - ELECTRICAL .................................................................... 187

6.9.13 SAMPLING SYSTEM - ELECTRICAL ............................................................................ 189

6.9.14 WEIGHERS - ELECTRICAL .......................................................................................... 190

6.9.15 TRAMP IRON MAGNETS AND METAL DETECTORS .................................................... 190

6.9.16 HYDRAULIC SYSTEMS - ELECTRICAL ........................................................................ 190

6.9.17 CABLE REEL SYSTEMS ............................................................................................... 191

6.9.18 CONTRACT DRAWINGS ............................................................................................... 191

6.10 SPARE PARTS ........................................................................................ 192


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6.10.1 GENERAL .................................................................................................................... 192

6.10.2 ESSENTIAL SPARES ..................................................................................................... 192 6.10.2.1 Generator .................................................................................................................. 192 6.10.2.2 Excitation System .................................................................................................... 192 6.10.2.3 Hydrogen Cooling System ....................................................................................... 193 6.10.2.4 Seal Oil System ........................................................................................................ 193 6.10.2.5 Medium (6.6kV) and Low (400V) voltage system .................................................. 193 6.10.2.6 Control Devices ....................................................................................................... 194 6.10.2.7 Cables ....................................................................................................................... 194 6.10.2.8 High Voltage Switchyard system............................................................................. 194 6.10.2.9 Communication systems .......................................................................................... 196 6.10.2.10 Coal Handling Plant ............................................................................................... 197

6.10.3 OPTIONAL SPARES ...................................................................................................... 200 6.10.3.1 Generator Circuit Breaker Scheme (GCB) .............................................................. 201

6.10.4 SPECIAL AND MAINTENANCE TOOLS ......................................................................... 201 6.10.4.1 Generator .................................................................................................................. 201 6.10.4.2 Generator Circuit Breaker Scheme (GCB): ............................................................. 201

6.10.5 CONSUMABLES ............................................................................................................ 201 6.10.5.1 High Voltage Switchyard system............................................................................. 202 6.10.5.2 Generator Circuit Breaker Scheme (GCB): ............................................................. 202

APPENDICES ................................................................................ 203

APPENDIX 1: .................................................................................................. 203

APPENDIX 2: .................................................................................................. 216

APPENDIX 3: .................................................................................................. 240

APPENDIX 4: .................................................................................................. 252


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6 ELECTRICAL EQUIPMENT

6.1 GENERAL

The Project will be built to supply power to the national power system.

This section details the technical requirements for the engineering, supply, manufacture, testing, inspection and commissioning of the main electrical Plant systems.

The General Conditions and General Technical Conditions shall be covered Volumes 1 and 2

The Contractor shall refer to the Circular of MOIT No.12/2010/TT-BCT dated April 15, 2010 for his design.

The Contractor shall supply complete electric equipment and associated auxiliaries including but not limited to the following:

1. Two generators, neutral earthing transformers and ancillary equipment.

2. Two Generator Circuit Breakers (GCBs), Phase Isolated Busbars (PIBs) and ancillary equipment.

3. Two sets of three-phase generator transformers and ancillary equipment.

4. All transformers (unit and station) and ancillary equipment.

5. All 6.6kV switchboards (unit and station).

6. All 400V switchboards (unit, station, actuator boards, soot-blowers etc.).

7. All 6.6kV and 400V motors.

8. Protection, synchronizing and metering systems.

9. 220V DC system, batteries, chargers, and UPS system.

10. Diesel generator system.

11. Cabling.

12. High voltage switchyard.

13. Communication System.

14. Miscellaneous power and lighting system.

15. Earthing and lightning protection.


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6.2 GENERATORS AND AUXILIARIES

6.2.1 Generator Design

The generator shall be of the horizontal, three phase synchronous machine, with rotating field, cylindrical rotor and totally enclosed, shall be designed and manufactured to comply with this Specification, IEC 60034-3 and the relevant other parts of IEC 60034, and shall be suitable in every respect for operation in the Vietnamese supply system in accordance with the specified conditions which follow.

The generator and auxiliaries shall also be designed and manufactured to follow, but not limited to, the below listed relevant standards.

IEC 60085: Electrical insulation—thermal evaluation and designation

IEC 60146: Semiconductor Converters

IEC 60076-11: Dry-type power transformers

IEC 60044: Instrument transformers

IEC 62053: Electricity metering equipment

6.2.1.1 Rating

The generator shall be continuously rated so as to enable a net output of 300 MW after deduction of excitation power and main oil pump power (if not driven by the Turbine-generator shaft) under the following conditions.

(1) 0.85 lagging power factor at any voltage between 100% and 105% of rated terminal voltage.

(2) 0.9 leading power factor and 95% rated terminal voltage.

6.2.1.2 Characteristics

The generator shall be designed to have the following characteristics:

(1) A short circuit ratio of not less than 0.5.

(2) A direct axis transient reactance (saturated) of not more than 35% on rated MVA.

(3) The overload ability of Generator is 1.5 rating current in at least 30 sec.

These limits shall not be exceeded when the applicable tolerances are taken into account. The applicable tolerances shall not be greater than that allowed by IEC 60034-3.

A generator capability curve is required to be provided as part of the bid, showing expected generator MW/MVAR operating limits at rated hydrogen pressure and lower.

6.2.1.3 Voltage and Frequency

(1) The generator shall be rated for 50 Hz operation.


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(2) Preferred value for generator voltage is 19kV but it may be nominated by the Contractor to optimize the design of all equipment operating at generator voltage.

Note: The auxiliary power system design calculations and equipment voltage (including transformer and tap changer) have been based on a voltage of 19kV. The Contractor has to review power system design and equipment specification to suit.

(3) The generator and generator transformer tap changer will be operated to maintain at the HV busbars a scheduled voltage which will be varied from time to time. Steady-state generator terminal voltage will vary continuously within a range of plus and minus 5% of rated voltage at any output within the generator capability, to satisfy these HV conditions.

6.2.2 Stator

6.2.2.1 Casing

(1) The casing of the stator shall be of fabricated construction gas-tight, and sufficiently robust to withstand the maximum forces set up in the event of an explosion of a hydrogen and air mixture in the casing.

(2) Access into the generator casing for inspection of stator end windings shall be by removal of bolted covers and shall not require the removal of coolers or other ancillary equipment.

(3) Liquid drains shall be provided from the casing, suitably enlarged, and connected to plates bolted to the generator frame so that on disconnection of any external drain there will be a hand hole for clearing material which may lodge in the internal drain. Liquid detectors, fitted with alarm contacts, shall be fitted in each separate drain and not in a common line.

(4) It is acceptable for the casing and core to be separate or integral according to suitability for transport and heavy lift arrangements.

6.2.2.2 Core

(1) The stator core shall be made up of high permeability low loss stampings, bonded and tightly clamped together to reduce noise and vibration to a practicable minimum. Attention shall be given to the prevention of excessive 100 Hz vibration being transmitted to the generator casing, foundations, pipes or associated equipment. The Contractor shall provide a description of the bonding used to prevent vibration of the end teeth, during the course of the Contract.

(2) Should the proposed method of transport require a beam to be threaded through the bore of the stator core then the full length of the bore shall be lined with a tube of leatheroid or similar material to prevent damage to the laminations during insertion and removal of the beam, and during transport.

6.2.2.3 Winding

(1) The winding shall be of an approved type in which replacement of a damaged portion is practicable. The winding insulation shall be of Class F temperature classification and of adequate thickness to withstand the voltage stresses which


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may occur in service. The part of the coil passing through the core slots shall be varnished with semi-conducting varnish, or have some other type of semi-conducting layer, in order to distribute in a uniform manner, the voltage gradient, to eliminate potential differences between the slot walls and the coil surfaces. Details shall be given during the course of the Contract on details of the winding and of the insulating materials proposed. The limit of winding insulation temperature rise shall not exceed that nominated in IEC 60034-1 for Class B insulation.

(2) The winding shall be effectively braced and blocked to withstand short circuits at the terminals under any operating condition and to prevent vibration which may lead to gas leakage. Materials liable to shrink in the course of time and on heating shall not be used for packing and wedging, and the general construction of the stator and the bracing of the winding overhaul shall be such as to provide adequate cooling surface and avoid "hot spots".

(3) Provision shall be made for preventing the formation of condensation during shutdown periods.

6.2.2.4 Terminals

The windings shall be star connected and the ends of each phase of the stator windings shall be brought to terminals accessible from a space in the foundation block. Adequate provision shall be made in the design of the foundation block for accommodation of the metering, protective and other Current Transformers (CTs) required for operating the unit. It may be taken that the CTs will not be in contact with the terminals and will be supported independently of the generator. Creepage distances shall be equivalent to those specified in IEC 60137 for medium polluted atmospheres as defined in IEC 60815. Connection boxes must be of a non–ferrous material to hinder overheating due to eddy currents.

6.2.2.5 Connection to Busbars and Earthing Transformer

(1) On the line side, provision shall be made for disconnection of the generator from the PIBs to enable the establishment of safety clearances between the two Plants during high voltage testing of either.

(2) On the star point side, provision shall be made for disconnecting the star point from the generator terminals to enable the establishment of safety clearances between the generator and the earthing transformer and to enable testing of individual phase windings.

6.2.3 Rotor

6.2.3.1 Winding

The design of the rotor shall be such that earth and interturn faults in the windings will not occur in service. Insulation shall be of Class F temperature classification. The limit of winding insulation temperature rise shall not exceed that nominated in IEC 60034-1 for Class B insulation.

The Contractor shall incorporate all latest design features to avoid permanent deformation of the winding during service. Packing blocks used in the rotor


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winding shall be of approved material and entirely suitable for the high temperatures and mechanical forces occurring in large rotors. Particular attention shall be given to the insulating and securing of the rotor winding connection leads to avoid vibration and the possible failure of either the lead or its insulation.

6.2.3.2 Shaft

(1) The rotor shall be made of one solid forging with high mechanical strength characteristics. The forging shall be fully examined by radiographic and ultrasonic techniques to determine its soundness.

(2) The Contractor shall incorporate suitable features in the rotor design to reduce the variation in rotor stiffness about the direct and quadrature axes, and thus minimize the resultant twice-per-revolution vibration levels. During the course of the Contract, design calculations shall be furnished to show that a rotor critical speed will not exist in the region of twice rated speed.

(3) The shaft shall have a reference mark of known relationship to the location of the magnetic poles which can be detected in-service for synchronism of shaft position with portable test equipment. The mark shall be located such that it is always accessible notwithstanding shaft expansion and provision shall be made for mounting of a detecting device.

6.2.3.3 Slip Rings

Slip rings where necessary shall be mounted on the shaft in a separate enclosure at the outboard end of the generator.

6.2.4 Generator Earthing

6.2.4.1 Neutral Point

The generator stator winding, which will be star connected, shall be suitable for earthing through a single-phase distribution-type double-wound transformer, the secondary winding of which will be shunted by a non-inductive resistance. The Contractor shall supply details of the capacitance to earth of the stator windings, which is necessary for selection of a final resistance value, as part of the commissioning report. The Contractor shall nominate the expected value of capacitance.

6.2.4.2 Casing

(1) Earthing terminals or bolts shall be provided at two positions on the stator bedplate for earthing the generator casing. These positions shall be connected at two different locations on the station earthing system.

(2) Major turbine-generator components shall be electrically bonded together and connected to the generator earth terminal to provide a low impedance return path for possible radio frequency (RF) voltage transients generated by thyristor switching in the generator static excitation circuit.


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6.2.4.3 Turbine/Generator Shaft Voltage/Current Control

(1) The shaft shall be earthed at one position between LP turbine and generator bearings by suitable multiple (at least two) shaft earthing devices.

The shaft earthing devices shall be protected from the effects of oil, dust, steam and other contaminants.

Each shaft earthing device shall have 0.01 to 0.1 ohm in-service contact resistance to the shaft at the rated speed and within permissible shaft vibration levels.

The contact element of each shaft earthing device shall be able to be replaced with the generator in service without safety risk either to a person or to the machine

(2) Each shaft earthing device shall be connected to the turbine/generator earth bonding conductors or lower bearing case via suitably sized low impedance current measuring shunt.

(3) The generator outboard bearings and preferably HP turbine bearing No. 1 shall be electrically insulated from the generator earth.

(4) Shaft voltage test terminals grouped in one single easily accessible location shall be provided for checking the voltages and insulation integrity for the following:

(a) Insulated bearings

(b) Insulated hydrogen seals

(c) Insulated oil piping

(d) Other insulated components as necessary.

(5) A continuous on-line shaft earthing monitor shall be provided as an integral part of the shaft earthing system.

The monitor shall measure earthing current and shaft voltage, and display these at a local panel adjacent to the generator. It shall also activate at least one "clean" changeover alarm contact.

A "Shaft Earthing Abnormal" alarm, displayed in the Plant Control Room (PCR), shall be generated for the following conditions:

(a) "Loss of power supply" to the monitor

(b) "Shaft earthing current low" (deterioration of shaft earthing device)

(c) "Shaft insulation low" (loss of insulation integrity)

Each alarm condition above shall be indicated by local LED and shall latch the local manually resettable alarm contact.

The monitor shall have an analogue 4-20 mA output for each parameter displayed on the local panel.

Analogue outputs shall be displayed in the PCR.


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(6) The Contractor shall provide details of shaft voltage/current control scheme monitors, the bearing insulation, shaft coupling insulation, shaft earthing devices and other similar monitoring equipment.

6.2.5 Generator Condition Monitoring

The Contractor shall provide the following generator condition monitoring equipment.

The Contractor shall describe the monitoring equipment to be supplied.

6.2.5.1 Core Monitor

The core monitor shall be of the type which samples hydrogen gas for the presence of particulates arising from severe overheating of the core and other machine components and raises an alarm.

The alarm shall be raised in the PCR.

6.2.5.2 Rotor Shorted Turns Detection Coil

The detection coil only shall be fitted to the generator with wiring brought out to terminals to enable connection of monitoring equipment as required. Monitoring equipment shall be supplied by the Contractor and shall raise an alarm in the PCR.

6.2.5.3 End Winding Vibration Sensors

Sensors only shall be fitted to the stator end windings at both ends of the generator with wiring brought out to terminals to enable connection of monitoring equipment as required. Monitoring equipment shall be supplied by the Contractor and shall raise an alarm in the PCR.

6.2.5.4 High Speed Electronic Fault Recorder

A high speed electronic fault recorder shall be supplied for transient fault recording of electrical parameters.

6.2.5.5 Partial Discharge Monitoring

The generator stator shall have continuous partial discharge monitoring equipment installed for condition monitoring of the stator insulation. Output signals are to be extended to the PCR and monitored via an independent monitoring station for recording and data storage. The equipment shall be noise immune to ensure precision of signals. Partial discharge monitoring equipment shall comply with the requirements of IEC 60060-1 and IEC 60270

6.2.6 Generator Excitation

6.2.6.1 General

Equipment for the complete excitation requirements of the generator shall be provided; including all excitation transformers, thyristor bridges, field suppression equipment, excitation control equipment and all connections between these items.


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The required excitation system shall be of a static system in which the excitation power is provided by a transformer connected to the switchyard side of the GCB and controlled by a thyristor bridge.

The excitation system shall be with dual channel Automatic Voltage Regulation (AVR) and Power System Stabilizers (PSS).

An off-line isolator shall be provided between the excitation transformer and the thyristor cubicle. A fixed earth switch on the thyristor side of the isolator shall also be provided. These are to enable electrical isolation of the thyristor cubicle for maintenance purposes without de-energizing the generator and unit transformers. The design of the isolator and earth switch shall be such that the status of the contacts can be seen to confirm electrical isolation and earthing respectively.

The excitation system shall be of a static converter directly supplying the generator rotor field. Its power source is derived from an excitation transformer which is connected to the generator side of the GCB via a PIB.

The excitation system is self-exciting, using DC “flashing” either from the 220V DC Station battery or from the 400V station supply to build up the initial field.

6.2.6.2 Performance

(1) The ceiling level of field voltage shall be at least 2.0 times the maximum continuous rating of field voltage, for stator voltages between 0.6 and 1.0 Per Unit (PU) of rated value.

(2) The excitation system offered shall be of the high initial response type, with a response ratio such that excitation increases from rated load excitation voltage 1.0 PU to a voltage greater than 2.0 PU in 0.1 secs in response to a step change in generator terminal voltage of 2.5%.

(3) The excitation system shall be capable of providing the peak power required for operation at ceiling voltage level.

This requirement is based on an operating duty cycle of: Rated Output (RO) for a sustained period, then ceiling voltage for 10 seconds, then return to RO for a sustained period.

(4) The Contractor shall provide, during the course of the Contract, performance details and preferably test curves for the design of excitation system offered.

(5) When the generator terminal voltage ranges from 80 to 120% of rated voltage and system frequency ranges from 47 to 52Hz, the field excitation system of the generator should be able to increase excitation voltage and current to 2.0 PU of the rated value in at least 30 secs.

(6) Changing speed of field excitation voltage should not be less than 2.0 times compared to rated voltage/second when the generator is running at rated capacity.


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6.2.6.3 Static Thyristors Excitation System

(1) Thyristors

(a) The thyristor bridge shall comply with the requirements of IEC 60146.

(b) A three-phase fully-controlled thyristor bridge shall be provided with sufficient redundancy to permit operation of the generator at full excitation power with 20% of the thyristors failed in any set of parallel paths i.e. arm of the bridge. It shall be possible to either replace faulty thyristors with the generator in service, or the extent of thyristor redundancy shall be sufficient, having regard to their reliability, to permit full excitation power without replacing thyristors more often than once every 4000 hours.

Sufficient redundancy shall be included in the thyristor cooling system to ensure that a single failure will not prevent the achievement of continuous 100% generator RO.

(c) The Contractor shall provide, during the course of the Contract, a description of what measures are taken to prevent damage to the thyristor bridge in the following situations (and any others as applicable) and what tests are performed to confirm the effectiveness of these measures.

A short-circuit at the generator slip rings at excitation ceiling voltage

An overload occurring with a sudden short-circuit at the generator terminals

High voltage across the bridge due to reverse excitation current

Non-uniform current distribution between thyristors.

(2) Excitation Transformer

(a) A power transformer shall be provided to supply the power requirements of the excitation system under all operating conditions. This transformer shall be a three-phase dry type natural air cooled and manufactured to IEC 60076-11 for indoor installation.

The design of excitation transformer shall take into account the additional stray and eddy current losses generated by the harmonics supplied to the load. The Contractor shall calculate the extra losses due to harmonics by reference to IEC 60076. The Contractor shall nominate the expected demand for excitation power (MVA) at rated generator output.

(b) Not withstanding the protection schemes specified in this Specification, the Contractor shall state any further protection which he feels is necessary for the safe operation of the transformer. The protection shall not mal-operate under any operating condition.

(3) Slip rings and Brushgear

(a) The slip rings and brushgear shall be of proven design and shall comply with the limits of temperature set out in IEC 60034.

The Contractor shall nominate the expected slip ring temperature at generator RO.


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The Contractor shall describe how the generator will be tested to determine that this limit is not exceeded.

(b) The Contractor shall nominate and guarantee the wear rates of the slip rings and brushes with the generator operating at continuous maximum rating. These wear rates shall be such that brushgear maintenance is not required more frequently than every 4000 hours of turbine-generator operation. The Contractor shall supply certificates and his experience list to demonstrate that the slip rings and brushgear meet these requirements.

(c) The brush pressure shall not require adjustment between the time of installation and the time of replacement of the brush. The construction shall permit safe and convenient replacement of the brushes with the generator in service. Suitable interlocking shall be provided so that the brushgear enclosure covers of only one polarity can be opened at any one time. The Contractor shall provide details of the provisions for safeguarding personnel engaged on "in service" brush replacement. Bolted connections shall be provided that will permit the polarity at the slip rings to be reversed.

(4) Field Suppression

A main field circuit breaker complying with IEC 60947 Parts 1 and 2, and a non-inductive resistor shall be provided for generator de-excitation. The circuit breaker shall be capable of breaking the field current under the most onerous operating conditions. On opening the breaker, the field winding shall be short-circuited through the resistor which shall ensure that the rotor winding voltage remains adequately below its test voltage. The field circuit breaker shall have two trip coils which are electrically and mechanically independent.

6.2.6.4 Supervision

Equipment shall be provided for detection of a generator rotor earth fault and measurement of generator rotor field voltage and current. The field voltage and current measurements will be computer monitored and used to compute field winding temperature. The Contractor shall provide during the course of the Contract details of the fault detection and voltage and current measuring equipment.

6.2.7 Excitation Control System

6.2.7.1 Construction and Reliability

The excitation control system shall provide completely reliable and stable automatic regulation of the generator excitation.

(1) Technology

The regulator shall be microprocessor based.

(2) Duplication of Automatic Control and Manual Control

Dual channel auto with a PSS for each channel is required. Manual control from PCR and local control are also required. Failure of both AVRs shall cause a


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transfer to manual and the generator shall remain in service. Power supplies for the AVR will be derived from the excitation transformer.

A full description of the AVR including the operation of functional units is to be provided by the Contractor.

The AVR shall have two completely independent reference, amplifier and control circuits, henceforth called channel 1 and channel 2 respectively. Duplication shall include connection to separate secondary windings of the generator stator Voltage Transformers (VTs) and to separate CTs.

Associated with each channel shall be a manual excitation current regulator, which shall be interfaced with the automatic excitation regulator as described in Clause 6.2.7.5.

(3) Operation of Duplicate Circuits

The aim of having duplicate regulators is to ensure that generator excitation remains under automatic control, notwithstanding a single failure in the control system.

In the following requirements, it is assumed that the two channels will operate on the duty/standby principle, although alternative principles such as master/slave will be considered provided they achieve the same aim.

The normal condition of operation when the generator is connected to the system will be for excitation to be under automatic voltage control of the selected duty channel, with the standby channel being also selected to automatic mode. If the duty channel in automatic mode fails, control will be transferred "bumplessly" to the standby channel (automatic mode). If the standby channel automatic control subsequently fails, control shall be transferred to the standby channel manual controller if available, otherwise excitation shall trip.

If the standby channel (in either automatic or manual mode) is unavailable when the duty channel automatic control fails, control shall be transferred to the duty channel manual controller if available, otherwise excitation shall trip.

The Contractor shall provide a description of what abnormal conditions will cause excitation to trip.

The equipment shall be designed and constructed so as to facilitate maintenance of one channel while the other remains in service.

If operating on the duty/standby principle, the standby circuit shall be continuously monitored so that any abnormality is alarmed and causes lockout of transfer to that circuit.

The status of each channel and whether it is controlling excitation shall be indicated in the plant control room. Selection of which channel is controlling excitation and its mode (automatic or manual) of operation shall also be available from the PCR.


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6.2.7.2 Characteristics

The excitation control system shall have the following characteristics:

(1) Sensitivity

The excitation system shall give its maximum or minimum output with variations in generator terminal voltage of not greater than ±2.5% from set point.

(2) Regulation

The regulator shall maintain the generator terminal voltage within limits of ±0.5% of required value between no load and full load over a range of frequencies of 47 to 52 Hz.

(3) Range of Control

The regulator shall be capable of automatically controlling the generator terminal voltage between the limits of 95% and 105% of rated voltage under all conditions of generator operation, when there is no contribution from any of the supplementary control circuits.

(4) Stability and Damping

It is intended that the excitation control system will be adjusted so that, with the generator operating on open circuit at rated voltage a step change in the AVR input equivalent to a step change of either +2.5% or -2.5% terminal voltage, shall result in an oscillation in field voltage with a settling time of less than 1.5 seconds.

(The settling time of a quantity is defined here as the time interval from the instant of the step change until the resulting oscillation settles to less than ±10% of the maximum induced change.)

It is also intended that the excitation control system will be adjusted so as to maintain stable operation of the generator for a ±0.5% step change in terminal voltage with the machine operating at all loads and power factors within its capability limits. The criterion of stability is a settling time of less than 5 seconds in generator terminal voltage and rotor angle oscillations.

In order to achieve these requirements, the Employer will carry out necessary calculations and advise the Contractor, before Site Commissioning, of the required setting values within the range of adjustment provided. The Contractor will co-operate in implementing these settings and in carrying out tests to verify that the required performance is attained.

(5) Low and High Frequency Operation

The regulator shall function satisfactorily at system frequencies between 47 Hz and 52 Hz.

6.2.7.3 Supplementary Controls

(1) The output of the excitation regulator shall be varied in accordance with the requirements of at least the following supplementary control circuits.

(2) Automatic Run-up and Run-down


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On closing the field switch during run-up of the generator, excitation shall be applied proportional to speed and increased until minimum set point voltage is achieved at not less than 95% normal speed. At the end of the excitation raising sequence, excitation shall be under AVR control.

The run-down sequence shall ensure that excitation is controlled so as not to overflux any transformers which may be connected to the generator.

(3) Reactive Power and Voltage Control

(a) Provision shall be made to allow the operator to select separate reactive limits for each generator for the reactive power sharing task, and the sharing to be apportioned accordingly. Control of the set point of each generator shall be selectable by the operator either by the Instrument Control and Monitoring System (ICMS) or to individual unit set point reference.

If the control system fails, control shall revert to individual control of each generator set point, the outputs retaining the values they had at the time of failure.

Provision shall be made for the following inputs and outputs from each unit:

Inputs: stator voltage, power output, reactive power output, 220kV busbar voltage, generator transformer tap setting.

Outputs: voltage set point, provision for generator transformer tap setting.

(b) Reactance drop compensation shall be included in the AVR circuits as a secondary means of minimizing changes in the 220kV busbar voltage level during changes in station reactive power demand.

The compensation shall be proportional to the reactive power output (or alternatively, quadrature component of stator current) of the generator and adjusted to a setting to be advised by the Employer.

(4) Stabilizing Controls

Stabilizing signals, derived from generator power output and/or terminal frequency and/or rotor speed shall be provided to enhance the damping of generator and power system oscillations over the frequency range 0.2 to 2.0 Hz. These shall be provided on both channels. The Contractor shall provide details of the stabilizing signals used. A compensating circuit separate from compensation of the voltage feedback path shall be provided. If more than one stabilizing signal is provided, separate compensating circuits are to be provided for each.

On the output of any stabilizer circuit, in the frequency range below 100 hertz, the total measured noise components shall be less than 0.1% peak to peak. This measurement shall be made with a flat compensation characteristic and the transducer gain adjusted to the following:

Stabilizer Gain

Frequency 20 (PU equivalent terminal voltage/PU frequency)

Speed: 20 (PU equivalent terminal voltage/PU speed)


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Power: 1 (PU equivalent terminal voltage/PU MVA)

The lag time constant of any speed, frequency or power transducer used as a feedback into the AVR should be less than 40 ms (as measured through the relevant stabilizer circuit, with compensation adjusted for flat response).

If a rotor speed based stabilizing signal is offered, the Contractor shall include details of any torsional interaction induced by the stabilizer (s) and of any special devices provided to avoid torsional oscillations. Analysis is to be included to demonstrate the performance of the AVR at the torsional frequencies.

The compensation circuits shall provide for the following gain and phase adjustments of the stabilizing signals:

Gain range 0-6,000 PU open circuit excitation volts per PU speed or frequency or range 0-100 PU open circuit excitation volts per 100 MW

Washout filter (high pass; at least three per stabilizing signal):

0 to 10 seconds adjustable

Lead/lag compensation (at least three per stabilizing signal):

0 to 1 second lead and lag, independently adjustable

(5) Over-Excitation Limit

The regulator shall incorporate an Over-Excitation Limiter (OEL) to restrict the period of operation of the generator beyond its continuous over-excited capability. The limit action shall have a time inverse characteristic corresponding to a small margin from the short time capability of the generator rotor and excitation system, and shall return operation to continuous rating. It shall operate smoothly, and without causing hunting. Its operation shall be alarmed in the PCR.

(6) Under-Excitation Limit

The regulator shall incorporate an Under-Excitation Limiter (UEL) to prevent operation of the generator while under AVR control beyond a characteristic line which will be advised by the Employer in the form of the locus of points on the MW versus MVAR capability diagram. The UEL shall operate smoothly, and without causing hunting. Its operation shall be alarmed in the PCR.

(7) Stabilizer Output Monitoring

(8) Cross Current Compensator (CCC)

(9) Automatic Follow-up Device (AFU)

In order to ensure a smooth change-over from the AUTO to the MAN and vice-versa an automatic follow-up shall be provided.

(10) Power System Stabilizer

The PSS is to improve the dynamic stability limit of the power system when the synchronous generator is in parallel operation with other generators on this system. The PSS should counteract the system instability when detected through the action of the static excitation system.


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The Contractor shall demonstrate that the stabilizer failure detection circuit does not operate inadvertently during system disturbances, particularly during the recovery of system frequency after loss of generation elsewhere in the system.

6.2.7.4 Supplementary Protection

The following supplementary protections are to be provided and their operation alarmed.

(1) Fuse Failure Protection

The excitation control system shall incorporate a means of detecting generator VT fuse failure. If such a failure is associated with the duty channel in automatic voltage control mode, control transfer shall be made in accordance with Clause 6.2.7.1.(3). If failure is associated with the standby channel, an alarm shall be raised and standby automatic control shall be excluded from the normal control transfer sequence. This facility shall not operate for low terminal voltage conditions arising from a fault on the system.

If fuses associated with both channels fail, control shall be transferred to manual.

(2) Rotor Over-Current Protection

If with the duty channel in automatic control, its OEL fails to operate as designed to prevent overheating of the rotor, a protective function shall operate to transfer control in accordance with Clause 6.2.7.1.(3). If subsequently, with the standby channel in automatic control, it’s OEL also fails to operate, a protective function shall operate to a further transfer of control in accordance with Clause 6.2.7.1.(3).

It should be noted that, in addition to the protective functions described above related to detection of OEL failure, excitation overcurrent protection is also to be provided, with which these functions should be graded.

(3) Overvoltage (or Overfluxing) Protection

Protection shall be provided against stator overvoltage and generator overfluxing. The Contractor shall provide the philosophy of the offered overfluxing protection scheme, including co-ordination with any excitation limiting function associated with run-up and shut-down of the generator.

(4) Underexcitation Protection

If with the duty channel in automatic control, its UEL fails to operate as designed to prevent pole slipping, a protective function shall operate to transfer control in accordance with Clause 6.2.7.1(3). If subsequently, with the standby channel in automatic control, it’s UEL also fails to operate, a protective function shall operate to a further transfer of control in accordance with Clause 6.2.7.1(3).

It should be noted that, in addition to the protective functions described above related to detection of limiter failure, loss of field protection is also to be provided, with which these functions should be graded.

6.2.7.5 Manual Excitation Control

The manual control shall meet the following additional requirements:


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(1) Follow-up

Equipment shall be provided to cause the manual excitation control to match the excitation level determined by the in-service automatic control, after a suitable time delay to avoid hunting, except in the circumstances described in Clause 6.2.7.5.(2). This is to ensure that a changeover from automatic to manual control, under steady state conditions, will generally take place without perceptible transients while operating in the generator capability range where manual control is stable.

Similarly, while under manual control, a facility shall be provided to match the automatic level of excitation with the manual level, so that a transfer to automatic control will take place without perceptible transients.

(2) Manual Restrictive Limit

(a) A facility shall be provided to prevent the manual controller operating point from following the in-service automatic controller operating point beyond a characteristic line known as the manual restrictive limit, which will be advised by the Employer in the form of a locus of points on the MW versus MVAR capability diagram. If protective transfer from automatic to manual control occurs while automatic is operating beyond the characteristic curve, it is acceptable that there be an immediate increase in excitation current and hence MVAR lagging output to bring the operating point within the characteristic curve.

(b) A facility shall be provided to prevent an operator reducing excitation current using a manual excitation controller beyond the characteristic curve described in (a). Further, if excitation is under manual control and the MW output is increased, a facility shall be provided which ensures that the manual operating point remains within the characteristic curve.

6.2.7.6 Test Facilities

(1) To facilitate performance testing of the AVR and for future investigations, data shall be made available for measurement at the excitation cubicle. The data shall include the following and may take the form of analogue signals or outputs from the digital software:

(a) Generator stator voltage and current

(b) Generator three-phase real and reactive generator power output

(c) Generator rotor voltage and current

(d) Instantaneous speed of the rotor (if speed is used as a PSS input)

(e) Any other signal used by the Contractor as a feedback in the AVR

(f) Intermediate signals at key points in the AVR block diagram.


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(2) Analogue transducers where required for processing primary signals shall be mounted in the excitation cubicle and have a time constant (lag) of less than 20 milliseconds.

6.2.7.7 Sources for Generator Voltage Signals

The generator voltage signal for each AVR channel shall be derived from two physically separate VTs. Each VT shall be separately connected to the PIBs and secondary wiring shall run in separate cables to the respective channels to minimize the possibility of a single event crippling both automatic regulators.

6.2.7.8 Performance Data

(1) The Contractor shall provide a block diagram so that it shows the gains, time constants, delays, limits and saturation of the excitation system as designed. Where these can be varied, ranges and recommended values are to be shown. Frequency response curves (Bode or Nyquist) of each block with the recommended settings are also required. The Contractor shall at appropriate times resubmit the block diagram amended to show the parameters and limits obtained during testing and again to show those which apply to the excitation system after Commissioning.

(2) Sample chart records of step response measurements made on machines having similar AVR control shall be provided during the course of the Contract.

(3) A curve shall be submitted during the course of the Contract showing the estimated time/voltage characteristic of the generator under AVR control immediately after full load has been rejected, by opening of the GCB.

6.2.8 Generator Cooling

(1) Cooling System

Core and rotor: direct hydrogen

Hollow stator conductor: direct hydrogen

For more information of hydrogen Plant and carbon dioxide supply, please refer to Volume 4..

(2) Generator cooling systems shall be provided to maintain the temperature of the various parts of the generator within the limits required by IEC 60034 at continuous RO.

(3) The complete equipment requirements for the following shall be provided:

1. Hydrogen cooling system,

2. Hydrogen seals and seal oil system,

3. Stator cooling system,

4. Brush gear ventilation system,

5. Generator casing purging

The equipment shall include all necessary pumps, valves, piping, reservoirs, make-up tanks, filters, heat exchangers, instrumentation and ancillary equipment.


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6.2.8.1 Hydrogen Cooling System

(1) A hydrogen cooling surface system shall be required at both ends of the generator shell to maintain the hydrogen temperatures within IEC 60034 specified limits. The hydrogen gas shall be force circulated through coolers by cooling fans coaxially fitted with shaft of generator. Water for coolers is supplied from cooler inlet water system via automatic controlled valve.

(2) The generator hydrogen pressure shall be maintained automatically at a set value which shall be adjustable.

(3) The hydrogen coolers use closed cooling water (demineralized water, refer to Volume 4).

Provision shall be made for any hydrogen leakage into the cooling water system in service to be detected, alarmed and the rate of leakage measured.

(4) Control equipment shall be provided to automatically maintain generator coolants at the required temperature by regulation of water flow through the various coolers.

(5) A covered water head tank shall be provided complete with inlet float valve and discharge piping and valves.

(6) Any apparatus necessary for the withdrawal of the hydrogen coolers from the Generator casing shall be provided by the Contractor and itemized in the Essential Tools and Appliances of the proposal documents.

(7) Drying equipment shall be provided for removal of moisture from the hydrogen in the generator. If the equipment uses desiccant, facilities shall be provided for its regeneration within the equipment without incurring the risk of hydrogen explosion. Equipment shall be provided for measurement of generator hydrogen dewpoint temperature and a signal provided for computer monitoring. In addition, facilities shall be provided for filling the generator with dry air and for passing dry air continuously when the generator is open for maintenance.

(8) An indicating and integrating flowmeter shall be provided for measurement of the hydrogen consumption rate of the generator. The range of the meter shall cover the flow rate for a "tight" generator up to the flow rate at which the unit must be taken out of service. The generator manufacturer shall state the maximum rate of hydrogen leakage from the generator as a whole when the generator is at rated conditions.

The flowmeter shall incorporate a transmitter for computer monitoring of gas consumption rate. Equipment shall also be provided for measurement of the gas mixture purity of hydrogen in air, hydrogen in carbon dioxide and air in carbon dioxide and signals provided for computer monitoring.

(9) Details of the source of hydrogen, its source pressure and its source dewpoint will be provided by the Contractor.

(10) All necessary hydrogen vent lines shall be provided and shall discharge at least 2000mm above the turbine house roof. All hydrogen piping routes shall avoid areas subject to a hazard from mechanical or fire damage.


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6.2.8.2 Generator Cooling Board

(1) A generator cooling board shall be provided to accommodate all the equipment associated with the control and monitoring of the generator cooling and seal oil systems, but excluding the generator purging system. This shall include control equipment, purity measurement equipment and instruments as recommended by the generator manufacturer. The board shall be located on the basement level of the turbine house.

(2) Intrinsically safe circuits complying with all the relevant parts of IEC 60079 shall be employed in areas where an explosive atmosphere could occur due to hydrogen leakage.

6.2.9 Hydrogen Seals and Seal Oil System

A seal oil unit shall be provided to safely contain the hydrogen gas within the generator housing.

The provided systems function shall be to prevent hydrogen from leaking out of the generator casing to atmosphere

Normally, the seal oil source is taken from the main lube oil pump upstream of lube oil control valve. The seal oil pressure in the system is automatically maintained at a preset point by a seal oil regulator. The seal oil discharged from sealing packing is routed back to the main oil tank through a set of stabilizing and degasifying equipment.

(1) In addition to the automatic seal oil regulator, the system shall be equipped with a manual standby feeding set ensuring the uncorrupted seal oil flow to the generator hydrogen packing even for a prolonged outage of the unit.

(2) The system shall also be provided with adequate monitoring and protecting equipment including liquid detectors etc.

(3) Shaft oil seals of a proven reliable design shall be provided. Details of the seals shall be provided by the Contractor. The seal oil to hydrogen differential pressure shall be maintained automatically at all pressures up to the maximum hydrogen pressure, irrespective of the source of seal oil. The system shall be capable of sealing rated gas pressure in the generator with the turbine-generator stationary.

(4) Two (2) sets of seal oil pumps shall be provided, one is a full duty cycle AC motor driven and the other is a fully duty cycle DC motor driven for emergency.

(5) Two (2) seal oil coolers shall be provided. These shall be cooled from the auxiliary cooling water system and shall be parallel on the water side. Adequate seal oil cooling shall be provided by one (1) cooler in service in case of a cooler inlet water temperature is low. The two (2) coolers may be paralleled to enable generator Maximum Continuous Rating (MCR) to be achieved in case of temperature is high.

(6) Equipment shall be provided for the treatment of seal oil to remove dissolved gas so as to minimize the contamination of hydrogen in the generator.


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6.2.10 Generator Casing Purging System

(1) The system shall permit purging the generator of hydrogen using carbon dioxide or compressed air, in less than 90 minutes with the generator stationary. The characteristics of the carbon dioxide supply shall be provided by the Contractor and shall also describe the details of the proposed purging system.

(2) A panel shall be provided from which all operations necessary for purging the generator can be carried out. The panel shall accommodate all monitoring equipment associated with the purging system. The panel shall be located on the basement level of the turbine house remote from the turbine-generator foundation block, so that it can be reached safely in the event of a generator fire. The interface, control and instrumentation, electric and mechanical, between this panel and local and remote control room shall be shown on a block diagram by the Contractor.

(3) The Contractor shall provide all necessary heating equipment should the carbon dioxide require warming prior to injection into the generator.

(4) Provision shall be made for a 'visible-break' between the generator and the sources of hydrogen, carbon dioxide and air so as to provide proof of isolation before access is made available for maintenance of the system. The visible breaks may include flexible hoses with quick disconnect couplings, or removable sections of pipework.

6.2.11 Temperature Measurement

(1) Temperature detectors shall be provided as described below and in compliance with IEC 60034. The detectors shall be either copper constant in thermocouples or platinum resistance thermometers, and shall be cabled to and terminated in junction boxes at the generator.

(2) Embedded temperature detectors shall be provided for measurement of generator temperatures as follows:

(a) A minimum of six (6) detectors per phase in the generator stator slots between the coil sides

(b) A minimum of two (2) detectors in the stator teeth,

(c) A minimum of two (2) detectors in the stator core

(3) Thermocouples shall be provided for temperature measurement as follows:

- Cooling air temperature rise across the generator slip rings

- Hydrogen temperature at the inlet and outlet of each hydrogen cooler

- Seal oil temperature at the inlet and outlets of each hydrogen seal.

- Cooling water temperature at the inlet and outlet of all heat exchangers

(4) Temperature detectors shall be provided as necessary for use in the ICMS control of generator coolant temperatures.


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6.2.12 Generator Current and Voltage Transformers

CTs and VTs shall be provided for metering, control and protection functions.

CTs in the generator stator winding terminals shall be independently supported and will not be in contact with the terminal (also refer to Clause 6.2.2.4 for more details).

The CTs and VTs used during acceptance testing of the turbine-generator and for tariff metering shall be calibrated in accordance with the appropriate test codes and standards by an approved independent testing authority in the country of manufacture.

6.2.13 Generator Fire Protection

Fire protection for the generator and related Plant is generally covered in Volume 5. The following clauses apply to particular requirements, for the generator and related Plant.

(1) The carbon dioxide purging system for the generator will be regarded as providing adequate fire protection for the interior of the generator.

(2) Generator slip ring fire protection equipment shall be provided.

(a) The equipment shall include detectors, nozzles, carbon dioxide injection equipment, piping, valves, and all other equipment necessary for automatic operation to facilitate fast extinction of fires. Facilities shall be provided to safeguard personnel who may be required to work in or near the areas being protected. Carbon dioxide supply shall be as per Volume 4.

(b) Provision shall be made for operation of the equipment from a remote push button, and also manually at the point of gas control but at a distance suitable to ensure safe operation for personnel.

(c) The pipe route from the carbon dioxide source shall be selected to avoid areas subject to the hazard of mechanical and/or fire damage.

(d) The equipment supplied shall include automatic closing fire dampers with carbon dioxide pressure-operated release mechanisms in the slip ring enclosure air inlet and exhaust ducting and in make-up air ducting (where slip rings and make-up air ducts are applicable).

(3) A system shall be provided for the detection of hydrogen leakage to atmosphere from the generator. In particular, detectors shall be located to detect leakage in the region of the rotating hydrogen seals and from the pipe connections below the generator. The detection of hydrogen leakage shall be alarmed in the fire detection system.


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6.3 AC AUXILIARY SYSTEM

(Refer to Appendices 3 & 4 for further specific requirement and arrangement details. The appendices take precedence over this sections contents.)

6.3.1 System Description

A main and auxiliary electrical power system is required to provide power for both normal and emergency operation of the unit and station auxiliary equipment. Refer to single line diagram Volume 9 Drawings. Note that this drawing is indicative only.

The ratings of each motor feeder circuit and transformer circuits shall be determined by the Contractor i.e. the load values indicated in this Specification are indicative estimates for system design purposes and not mandatory constraints on the Contractor.

This auxiliary electrical power system shall be fed from two voltage levels as follows:

(1) 19/6.6-6.6kV system: unit transformer which is connected to the Generator output busbars and upstream of the generator transformer.

(2) 220/6.6-6.6 kV System: Station Transformer is to be connected to the 220kV switchyard busbar which is capable of being supplied via the double circuit 220kV THAI BINH TPP – THAI BINH transmission lines in the 220kV switchyard.

The 220/6.6-6.6kV station transformer shall supply power from the system to the Plant to service plant startup or to take the place of the unit auxiliary transformer in case of failure to ensure a continuous power supply for the unit AC 6.6kV auxiliary system.

The design of the main and auxiliary electrical power system shall obey Viet Nam and International standards, comprising but not limited to the following:

IEC 60038 – IEC standard voltages

IEC 60076 – Power transformer

IEC 60214 – On Load Tap Changer (OLTC)

IEC60296 - Specification for unused Mineral Insulating Oils for Transformersand Switchgear

IEC 60345 – Method of testing for electrical resistance and resistivity of insulating materials at elevated temperatures

IEC 60076-10 – Power transformers – Determination of sound levels

IEC 60214-2 – Tap-changers – Application guide

IEC 62271-100 – HV AC circuit breakers


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IEC 62271-200 – HV AC metal enclosed switchgear and control gear

IEC 60470 – HV AC Contactors and Contactor-Based Motor-Starters.

IEC 62271-105 – HV AC switchgear and control gear – switch-fuse combinations

IEC 60947-3 – LV – Switches, disconnectors, switch-disconnectors and fuse-combination units.

IEC 62271- 102 – HV AC – Disconnectors and earthing switches.

IEC 61439 – Low-voltage switchgear and controlgear assemblies

IEC 60898 – Electrical accessories – Circuit-breakers for overcurrent protection for household and similar installations

IEC 60282 – HV fuses

IEC 60269 – LV fuses

IEC 60787 – Application guide for the selection of high-voltage current-limiting fuses-links for transformer circuits

IEC 60529 – Degrees of protection provided by enclosures (IP Code)

IEC 60947 – Low-voltage switchgear and controlgear

IEC 60034 – Rotating electrical machines

IEC 60623 – Secondary cells and batteries containing alkaline or other non-acid electrolytes

IEC 60228 – Conductors of insulated cables

IEC 60502-1 – Power cables with extruded insulation and their accessories for rated voltages. from 1kV up to 30kV – Part 1 Cables for rated voltages of 1kV and 3kV

IEC 60502-2 – Power cables with extruded insulation and their accessories for rated voltages. from 1kV up to 30kV – Part 1 Cables for rated voltages from 6kV up to 30kV

IEC 61386 – Conduit systems for cable management

6.3.1.1 General Technical Requirements

The equipment ratings and parameters shall meet the general technical requirements of Volume 2.

It should be noted that rating parameters and Plant specifications are based on IEC standards and that voltage levels of 6.6kV and 400V be adopted as follows:

(1) 6.6kV, 3 phase, 3 wire for motors rated above 200 kW and for bulk power distribution.

(2) 400V, 3 phase, 3 or 4 wire for motors rated up to 200 kW and for other 3 phase loads.

(3) 230 V AC, 2 or 3 wires for small loads requiring single phase power: for maintenance sockets, space heaters, enclosure interior lighting, ventilation fans, convenience outlets, etc.


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(4) 400/230 V AC 50 Hz regulated single or three-phase Uninterruptible Power Supply (UPS) shall be available for vital/critical Plant instrumentation and control and plant emergency lighting supplies. Earthing and protection systems against electrical shock shall be the same as selected for normal 400/230 V AC systems.

6.3.1.2 Generator Circuit Breaker Scheme

The GCB scheme provides the following redundancy principles fundamental to the design.

(1) The worst effect of withdrawing any switchboard busbar from service is loss of one generating unit.

(2) Withdrawal of any single auxiliary transformer from the system can be accommodated without loss of generating output.

In meeting principle (2) above the GCB scheme employs one 44MVA unit transformers and one 44MVA station transformer. The single station transformer is common to both units.

Primary features of the AC system are as follows:

(1) 6.6kV system resistance earthed (to limit fault damage)

(2) 400V system solidly earthed (necessary for reliable protection)

(3) A 400V emergency power supply system is required to protect the boiler/turbine-generator Plant and to maintain essential power necessary for the safety of personnel in the event of loss of normal AC supplies. The prospective sources of emergency power are two 6.6kV/400V-1.2MVA emergency transformers and one (1) 1000kVA emergency Diesel generators per Unit. These Diesel generators shall be rated for the shutdown requirements of the generating units.

(4) The impedance of each transformer shall be such that voltage regulation shall be within the specified limits referred to in Volume 2 and shall be such that the fault withstand capability of its connected equipment is not exceeded.

(5) The interfacing of the main switchboards with the ICMS is shown in Volume 9 Drawings.


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6.3.1.3 Loadings and Transformer Ratings

(1) Loadings

The ratings depicted in the appropriate drawing, Volume 9 Drawings have been developed from the rating estimates and duty points of unit and station auxiliary drives, which are shown on the following Table 6.3.1 (Note: all figures are preliminary only).

Table 6.3.1a: Unit Load Estimate

Name Motor/ Transformer Rated Power

Quantity Total Loads @80% Rated Power (Duty

Point)

Remarks

KW KVA KVA

FDF 1342 1579 2 of 2 2526

IDF 1063 1250 2 of 2 2000

PAF 927 1090 2 of 2 1861

PULV 1388 1633 3 of 4 3920

FGD Boost up Fan&Equip

797 939 1 of 1 751

BFP 2381 2801 2of 3 4482

CP 500 588 1 of 2 470

CWP 1200 1412 2 of 3 2260

FGD Absorber Rec.P

250 295 2 of 3 470

ESP 550 1 of 1 440

Unit Aux. TR 2500 2 4000 Assumed loads

Total Estimates of Unit Loads 23180

Legend:

FDF: Forced Draft Fan

BFP: Boiler Feed Pump

CWP: Cooling Water Pump


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CP: Condensate Pump

PAF: Primary Air Fan

PULV: Pulverizer

IDF: Induced Draft Fan

ESP: Electrostatic Precipitator

FGD: Flue Gas De-Sulphurisation

Table 6.3.1b: Estimates of Station loads (duty points)

Plant/SYSTEM Loading kVA

Ash & Dust 1000

Coal Handling Plant & Coal Bunkering 3000

Station Aux. TR 2500 Assumed Loads

HVAC 1000

Admin Building 600

Water Treatment (Waste & Raw) 800

Air Compressors 700

220kV Switchyard 600

Contingency 1300

Total Station Load: 11500

(2) Transformer Ratings

The total load for each transformer shall not exceed 80% of the transformer rating. Accordingly, the total rating for each unit transformer is calculated as follows:

Unit Load: 23180kVA

Station Load: 11500kVA

Total transformer load = 23180+11500 = 34680kVA

Transformer Rating = 34680/0.80= 43350kVA


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Rounded up transformer rating: 44MVA

Therefore the rating of each unit transformer (19/6.6kV) is estimated to be 44MVA.

The station transformer is required to have the same rating of 44MVA as the unit transformers to meet the redundancy principles as stated in Clause 6.3.1.2 (2).

The above estimated ratings of transformers and motor feeder circuits have to be adjusted following discussion and negotiation of loading details with the Plant suppliers i.e. the above load values are indicative estimates for system design purposes and not mandatory constraints on the Contractor.

The Contractor shall submit his own assessment and justification of duty point loadings together with appropriate adjustments to the auxiliary supply system ratings (essentially the transformers) which flow from it.

However, the total load to be carried by each transformer shall not exceed 80% of the transformer rating. The Contractor's assessment shall also account for the active and reactive components of the loads.

6.3.1.4 System Configuration Interlocking

The configuration of the 6.6kV and 400V networks shall be constrained by electrical interlocking and functional switching arrangements achieved through the ICMS system to meet the following requirements.

(1) 6.6kV System:

No paralleling operation permitted between any of the two supply points to the system i.e. the system shall be constrained to run as single radial transformer supplies so that fault levels applied to the 6.6kV system are held well within the 6.6kV switchgear short circuit rating at all times. The only exception is when it is required to parallel supplies temporarily in order to take one supply out of service for maintenance reasons.

(2) 400V System:

The system is configured to operate within the switchgear short-circuit rating subject firstly to the transformers running as single radial supplies. Secondly fault rating allowance is included to permit a single Diesel generator to operate in parallel with a single transformer supply. These limitations shall be achieved through ICMS logic to the 400 V switchgear as follows:

(1) None of the four transformer supplies to be allowed to form a parallel circuit.

(2) Synchronisation of Diesel-Generator A to be permitted on its own circuit breaker only.

(3) Synchronisation of Diesel-Generator B to be permitted on its own circuit breaker only.


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(4) No paralleling allowed between Diesel-Generator A and Diesel-Generator B.

(5) If Diesel-Generator A circuit breaker is closed then no further 400 V circuit breaker closure to be allowed which would have the effect of coupling Diesel-Generator A back into the 6.6 kV system.

(6) If Diesel-Generator B circuit breaker is closed then no further 400 V circuit breaker closure to be allowed which would have the effect of coupling Diesel Generator B back into the 6.6 kV system.

(7) Closure of either Diesel-Generator A or Diesel-Generator B onto a dead busbar only permitted provided the busbar is isolated at 400 V i.e. not connected back into the 6.6 kV system.

6.3.1.5 Automatic Switching

The philosophy of transfer of 6.6kV supplies from unit transformer to station transformer (and vice versa) is based on plant generating capacity being maintained. Contractor shall describe its method of transfer employed to prevent connected motors from dropping out when a unit or station transformer needs to be isolated following an internal fault. Automatic transfer and interlocking shall be through the DCS. The philosophy of transfer of 400V supplies is similar, but the following requirements shall also be considered.

Automatic operation, DCS interlocking and appropriate unit auxiliary 400V switchboard Under Voltage (UV) protections shall also accomplish the following.

Unit auxiliary switchboard essential busbar UV protection shall be subject to delayed operation by several seconds following non-essential busbar UV operation. In that period automatic control shall initiate the following operations:

Closure of the 400V station to unit interconnection i.e. attempted restoration of unit auxiliary 400V essential supply from the associated station source.

In the event that the above switching does not affect supply restoration (e.g. due to total power station AC supplies having been lost) initiate automatically the start and run up of the associated Diesel generator making it available for automatic connection to the essential supplies busbar.

6.3.1.6 Circuit Allocations

The Contractor shall ensure that the design includes all electrical power supply systems for all electrical consumers in the plant for a proper function of the plant based on a preliminary equipment list of all process Plant requiring electrical power. Contractor shall as soon as possible establish a comprehensive equipment list identifying all equipment in order to design the power supply network accordingly.


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The design of the power supply network shall preserve a distinction between "unit" and "station" auxiliaries with unit auxiliaries defined as items which are identified with the generating unit only, whereas station auxiliaries are related to common station services such as the coal plant, ash plant, etc. Complete listings of unit and station Plant shall be proposed by the Contractor and agreed by the Employer. It is expected that the listings would be closely based on the tables detailed in Clause 6.3.1.3. Unless otherwise agreed, unit auxiliaries shall be supplied from the relevant unit 6.6kV or 400V unit auxiliary switchboards and station auxiliaries from the station 6.6kV or 400V station switchboards.

6.3.1.7 Load Identification and Measurement

The unit Plant which must run for a generating set to operate continuously at 100% RO shall be nominated by the Contractor and agreed with the Employer. Similarly the unit Plant necessary for continuous operation at 75% RO shall be nominated and agreed.

The Contractor shall state the number of units of a given auxiliary required in service together with the nominated kW loading for 100% and 75% RO continuous operation.

6.3.1.8 Fault Levels

The fault level for the 6.6kV switchboard busbars shall be minimum 50kA rms symmetrical for 1 second and for 400V switchboard busbars shall be minimum 60kA rms symmetrical for 1 second . Actual fault levels shall be calculated by the Contractor and agreed with the Employer.

6.3.1.9 Voltage Distribution and Regulation

(1) Equipment requiring AC power supply at voltages other than those described above shall be used only with the approval of the the Employer, and in all such cases the Contractor shall provide all necessary devices to transform regulate or control the specified power supplies to those required by the equipment. Total galvanic isolation shall be achieved between systems operating at different voltage levels.

(2) Where 230V single phase power supply is required, the load on any circuit shall not exceed 35A. Where the equipment contains several single phase loads and the total load exceeds 35A, the equipment shall be supplied at 400V - 3 phases, and the individual loads balanced across the three phases as equally as possible.

(3) All equipment provided shall be entirely suitable for operation between the limits of variation in the specified AC power distribution system as described below.

(4) Under steady-state conditions the frequency may vary between 51 Hz and 49 Hz. with short-term excursions down to 47 Hz.

(5) Under steady-state conditions the voltage may vary between + 5% of nominal voltage, at 19kV phase-isolated bus. Additional voltage drop at equipment load terminals due to cable impedance shall be a maximum of 5% of nominal voltage.

(6) During the starting of large motors, short-term voltage excursions of up to -10% may be experienced at the source of supply. The total allowable voltage drop at


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equipment load terminals under these conditions including cable impedance voltage drop shall be limited to 15% of nominal voltage.

(7) All equipment supplied shall be capable of withstanding complete loss of, or sudden restoration of, the AC power supply system without suffering any damage.

6.3.2 Transformers

6.3.2.1 220/19kV Generator Transformer

The generator transformers shall be mineral oil immersed and meets the following specification and the general technical requirements of Volume 2.

The impedance of the generator transformers indicated in this Specification is only the indicative value for system design purposes. The Contractor shall determine the appropriate impedance value such that voltage distribution, regulation and fault withstand capability of its connected equipment shall be within the specified limits referred to in Volume 2.

Standard: IEC 60076

Type: 3 phase, 2 winding transformer

Rating: 353MVA (OFDAF)

Voltage: 220kV ± 15%/19kV

HV terminals: Outdoor bushing - heavy pollution level to IEC 60815 and IEC 60137

HV neutral terminal: Outdoor bushing - heavy pollution level to IEC 60815 and IEC 60137

LV terminals: Bushing-connected to PIB medium pollution level to IEC 60815 and to IEC 60137

Tap changer: On-load (with AVR) - IEC 60214

Tapping Range: ± 15% in 1.5% steps on HV Side

Impedance: 14-15% over tapping range

Cooling: OFDAF (coolers for 100% duty plus one spare cooling unit)

Vector Relationship: YNd11

Insulation Levels: 220kV system 19kV system

Lightning Impulse: 1050kV 125 kV

Power frequency: 460kV 50kV

Bushing Current Transformer

as per IEC 60185 and IEC 60044

- Accuracy: 0.2; Protection cores: 5P20

Sound Level: as per IEC 60076-10

Fault levels at voltage levels (220 kV, 19kV) shall be verified by the Contractor.


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6.3.2.2 19/6.6-6.6kV Unit Transformers

The 19/6.6-6.6kV unit transformers shall be three-phase, mineral oil immersed transformers and meet the following specification and the general technical requirements of Volume 2.

The rating and impedance of the 19/6.6-6.6kV transformer indicated in this Specification are only the indicative values for system design purposes. The Contractor shall determine the appropriate values of transformer rating and impedance such that voltage distribution, regulation and fault withstand capability of its connected equipment shall be within the specified limits referred to in Volume 2.

Standard: IEC 60076


Rating: 44 MVA (ONAF)

Voltage: 19kV ± 10%/6.6-6.6kV

Impedance: 12.5% on principle tap

Cooling: ONAN/ONAF (100% duty with one cooler unit out of service)

Vector Relationship: D/yn1-yn1

Terminals:

HV: Bushing - connected to PIB medium pollution level to IEC 60815 and to IEC 60137

LV phase: Cable boxes (outdoor bushing medium pollution class to IEC 60815 and to IEC 60137)

LV neutral: Cable box (outdoor bushing - medium pollution class to IEC 60815 and to IEC 60137)

Insulation Levels: 19kV system 6.6kV system

Lightning Impulse: 125kV 60kV






Fault levels at voltage levels (19kV, 6.6kV) shall be verified by the Contractor.


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6.3.2.3 220/6.6-6.6kV Station Transformer

The 220/6.6-6.6kV station transformer shall be a three-phase, mineral oil immersed transformer and meets the following specification and the general technical requirements of Volume 2.

The rating and impedance of the 220/6.6-6.6kV transformer indicated in this Specification are only the indicative values for system design purposes. The Contractor shall determine the appropriate values of transformer rating and impedance such that voltage distribution, regulation and fault withstand capability of its connected equipment shall be within the specified limits referred to Volume 2.

Standard: IEC 60076


Rating: 44 MVA (OFAF)

Voltage: 220kV ± 9x1.78%/6.6-6.6kV

Stabilizing Delta winding: 5 MVA minimum

(be capable of withstanding max short circuit)

Impedance: 12.5% on principle tap

Cooling: ONAN/ONAF/OFAF

Vector Relationship: YNyn0yn0d11

HV terminals: Outdoor bushing - heavy pollution level to IEC 60815 and IEC 60137

HV neutral terminal: Outdoor bushing - heavy pollution level to IEC 60815 and IEC 60137

LV terminals: Bushing-connected to PIB medium pollution level to IEC 60815 and to IEC 60137

Insulation Levels: 220kV system 6.6kV system

Lightning Impulse: 550kV 60kV






Fault levels at voltage levels (220kV, 6.6kV) shall be verified by the Contractor.

6.3.2.4 6.6kV/400V Unit Auxiliary Transformers & Station Auxiliary Transformers

The 6.6kV/400V unit auxiliary transformers & station auxiliary transformers shall be three-phase, dry type transformers and meet the following specification and the general technical requirements of Volume 2.


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The rating and impedance of the 6.6kV/400V transformers indicated in this Specification are only the indicative values for system design purposes. The Contractor shall determine the appropriate values of transformer rating and impedance such that voltage distribution, regulation and fault withstand capability of its connected equipment shall be within the specified limits referred to in Volume 2.

Standard: IEC 60076-11

Rating: 2.5MVA

Vector Relationship: Dyn11

Type: Cast Resin

Voltages:

HV - 6.6kV

LV - 400 V

Impedance: 7.5% on the principal tap

Tap changer: Off-load

Tapping Range: 6.6kV ± 2x2.5%

Terminals:

HV: - Cable box

LV: - Bolted directly onto switchboard busbar

Cooling: AN (Enclosed type)

Insulation Levels:

HV - Lightning impulse - 60kV

- Power frequency - 20kV

LV - Power frequency - 3kV

Sound Level: IEC 60076-10

6.3.2.5 6.6kV/400V Emergency Transformes

The 6.6kV/400V emergency transformers shall be three-phase, dry type transformers and meet the following specification and the general technical requirements of Volume 2.

The rating and impedance of the 6.6kV/400V transformers indicated in this Specification are only the indicative values for system design purposes. The Contractor shall determine the appropriate values of transformer rating and impedance such that voltage distribution, regulation and fault withstand capability of its connected equipment shall be within the specified limits referred to in Volume 2.

Standard: IEC 60076-11


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Rating: 1.2MVA

Vector Relationship: Dyn11

Type: Cast Resin

Voltages:

HV - 6.6kV

LV - 400 V

Impedance: 5% on the principal tap

Tap changer: Off-load

Tapping Range: 6.6kV ± 2x2.5%

Terminals:

HV: - Cable box

LV: - Bolted directly onto switchboard busbar

Cooling: AN (Enclosed type)

Insulation Levels:

HV - Lightning impulse - 60kV

- Power frequency - 20kV

LV - Power frequency - 3kV

Sound Level: IEC 60076-10

6.3.3 Switchgear

6.3.3.1 General

This section establishes the criteria for the switchgear to be incorporated in the medium (6.6kV) and main low voltage (400V) power distribution systems.

For general switchgear and switchboard requirements that also apply to this section refer to Volume 2.

6.3.3.2 Medium Voltage Switchboards (6.6kV)

(1) Switchgear

(a) A spare circuit breaker/switching device shall be provided for each current rating.

(b) The circuit breakers and switching devices shall be capable of meeting their rated performance when the voltage at the closing device or at the shunt trip coils is any value from 176 V to 264 V.

(c) Equipment Description/Ratings:

Circuit Breaker


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Voltage: 6.6kV

Phases: 3

Frequency: 50 Hz

Current Rating: To be determined from load and the specification requirements (Sections 6.3.1 and 6.3.2)

Breaking and Short-Time Current Capacity:

50 kA (1 second) with a DC component as per IEC 62271-100

Circuit Breaker Type: Vacuum and sealed for life (or equivalent)

Control Voltage: 220 V DC

Impulse Withstand Voltage:

60kV peak

Power Frequency

Withstand Voltage:

20kV

(2) Switchboards

(a) The HV connection between the 6.6kV switchboards and the associated auxiliary transformers shall be either by HV busduct or cables. The supply arrangement shall be determined on economic grounds when the location of the transformers and switchboards are finalized.

(b) As part of the ICMS interface, the Contractor shall provide a power (watts) and/or current transducer on each circuit. These transducers shall have an output with a range of 4-20 mA. Supply power for the transducer shall be obtained from the relevant switchboard control circuit. Power transducers are required on all 6.6kV circuits and 400V incoming circuits. The remaining circuits shall have current transducers.

(c) Switchboard circuits shall be provided in accordance with the switchboard single line diagrams and circuit schematic diagrams.

(d) Switchboard Busbars:

Type: Hard drawn copper (single busbar arrangement)

Rating: 3150A or as otherwise agreed

1500A (Neutral)

DC control busbars (rated to carry the current necessary for the simultaneous tripping or closing of all circuit breakers, whichever is the greater)

Fault and Short time Current Rating:

50 kA rms symmetrical for 1 second

(3) Supporting Drawings

Reference Drawing: Volume 9 Plant Single Line Diagram


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6.3.3.3 Low Voltage Switchboards (400V)

(1) Switchgear

(a) The 400V circuit breakers shall be capable of meeting their rated performance when the voltage at the closing device or at the shunt trip coils is any value from 176 V to 264 V.

(b) Contactors shall be co-ordinated with the operating characteristics of associated short circuit protection such that short circuits do not cause welding of the contacts.

(2) Circuit Breakers

Voltage: 400V

Phases: 3

Frequency: 50 Hz

Current Rating: To be determined by load requirements

Breaking and Short- Time Current Capacity:

60 kA (Final data on 400V switchgear and switchboard shall be verified and determined by short circuit and load flow calculations by the contractor) (1 second) rms symmetrical

Circuit Breaker Type: Air-Break

Control Voltage: 220 V DC

Impulse Withstand Voltage: In accordance with IEC 61439-1 Annex G

(3) Switchboards

(a) Each main 400V switchboard in the main control building shall be provided with 20% spare compartments with all hardware provided to receive starter modules.

(b) The main 400V switchboards shall be directly connected by busbar and enclosure to their respective 6.6kV/400 V dry type transformers.

(c) The switchboards shall have been tested for arcing fault containment to IEC 61439 and shall have separate compartments for the following:

Busbars

Combined Fuse Switches (CFS) or moulded case circuit breakers

Contactors (where applicable)

Control cable terminals, control fuses, current transformer links, protection and auxiliary relay

Voltage transformers

Current transformers and power cable terminations

(d) Arc fault containment shall be to IEC 61439


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(e) Compartmenting shall be such that maintenance can be carried out safely on one circuit with the other adjacent circuits in service.

(f) Power transducers and current transducers shall be provided for all 400V incoming circuits. Current transducers shall be installed on all remaining 400V feeder circuits. The transducers shall have an output with a range of 4-20 mA.

(g) The main busbars and all connections thereto and busbar supporting insulators shall be capable of withstanding for 1 second the mechanical and thermal stresses arising from the maximum possible fault currents.

(h) Switchboard Busbars

Voltage: Hard drawn copper (single busbar arrangement)

Rating: 4000A or as otherwise agreed (Phase)

1500 A (Neutral)

DC control busbars (rated to carry the current necessary for the simultaneous tripping or closing of all circuit breakers/contactors, whichever is greater)

Fault and Short Time Current Rating:

60 kA (Final data on 400V switchgear and switchboard shall be verified and determined by short circuit and load flow calculations by the contractor) (1 second) rms symmetrical

6.3.3.4 Drawings and Design Documents

The following Drawings and design documents shall be provided by the Contractor during the course of the Contract:

(a) Detailed layout of all switch rooms.

(b) Detailed layout of MV (6.6kV) and LV (400V) switchboards.

(c) Detailed listed of electrical consumers with load data.

(d) Load balance.

(e) Single line diagrams for all 6.6kV and 400V switchboards.

(f) Control schematics, termination and wiring diagrams for all 6.6kV and 400V switchboards.

(g) Load flow and fault calculation (three phases and single phase to earth fault level) for the entire power system at all voltage levels.

(h) List of cable with length of each cable line.

(i) Drawing of cable arrangement (Cable route layout, civil Work guide Drawing of cable canals, cable arrangement in canal).

(j) Relay setting calculation guide documents.

(k) Electronic Drawing files under AutoCAD form.


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(l) Operating and maintenance manual. Integrated operating and maintenance manual should be provided for all electrical systems.

(m) Training manual.

6.3.4 Electrical Protection and Metering

6.3.4.1 General

Note: Control and relay protection system of electrical equipment of the Project shall be designed to meet Vietnam standards, EVN regulations as well as specified international standards. Control and relay protection system is designed according to following documents:

- Electric Protection - Part IV-11TCN-21-2006 (issued by MOI)

- Official letter 5498/EVN-KTSX dated 27/11/2008 of EVN on the manufacture of relays.

Technical specification of relay

- Rated frequency: 50 Hz

- Rated input current: 1A

- Rated input voltage: 110 V AC

- Operating voltage: 220V DC

- Type of main relays: digital relay with microprocessor

- Manufactures of main relays: ABB, Siemens, Areva (Alstom), SEL, Toshiba or equivalent.

Standard of protection equipment: IEC 60255

This section established the criteria and minimum requirements for the protection of the power station electrical system comprising the generator, generator transformer, generator excitation transformer, unit transformer station transformer, 6.6kV and 400V AC auxiliary power systems. The 6.6kV and 400V auxiliary power systems comprise the main switchboards in the central control building and other control buildings together with associated outgoing circuits. General protection and metering clauses, applicable to all areas of the plant are detailed in Volume 2.

The Contractor shall also provide a dual, fully duplicated unit synchronizing system. It shall include duplicated automatic synchronizers, manual check synchronizer and other indicating instrument to allow automatic and manual synchronizing of the GCB.

The Contractor shall also provide a station synchronizing system which includes a manual check synchronizing relay for the 6.6kV station incomers and unit-station interconnector circuit breakers.

The electrical protection schemes shall be designed so as to promptly, precisely and reliably isolate from service any element of the power system when that element is subjected to an abnormal condition detrimental to its effective


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operation, while leaving other unaffected elements in service. The protection schemes shall also be designed so that they do not operate under load conditions or faults external to the relevant zone.

The protection systems shall be based on digital, microprocessor based device with monitoring, measurement and communication capability.

The communication output ports of the numerical generator protection systems (No. 1 and No. 2 schemes), station transformer protection system and of the protection relays used in MV (6.6kV) power system shall be connected to the central monitoring, relay setting and recording station which will be located as close as possible to the PCR.

Suitable menu-guided software to communicate with these protective relays via a personal computer shall be provided, installed and tested to a satisfactory performance. This central monitoring and control station shall be connected to the Station ICMS via a “miscellaneous station system” drop.

The protection relays and systems shall meet all requirements of IEC 60255 and other relevant IEC standards.

(a) Design philosophy

In general, the 6.6kV power system shall be non-effectively earthed via 5.8ohm resistors connected to the neutral points of 6.6kV windings of power transformers. These 5.8ohm resistors are to limit earth fault current to approximately 1000A and shall meet maximum time duration of 30 seconds.

Neutral earthing transformers shall be provided for non-effective earthing of the neutral points of the generators and the neutral displacement relays shall be connected to the secondary side of these transformers.

The protection systems shall include at least the following:

Generator:

Under impedance

Generator Volt/Hertz over fluxing

Stator earth fault protection

Undervoltage-ground detection

Reverse power protection

Loss of excitation (Field failure)

Negative phase sequence protection

Overcurrent for breaker failure

Overcurrent inverse characteristics-voltage restraint

Overvoltage-ground detection

Fuse failure sensed by unbalanced voltage and current

Three Phase Differential/ percentage differential


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Multi-trip latched relay

Generator Transformer:

Differential (separate for 220kV line)

High-set overcurrent

HV Restricted & standby earth fault

IDMT & instantaneous overcurrent

Zero sequence for earth fault

Transformer overfluxing

Buchholz (Oil level, surge, gas)

Main tank overpressure (Qualitrol)

Tap changer overpressure

Oil and Winding temperature

Fan failure

Station Transformer:

Differential


Restricted & standby earth fault

IDMT & instantaneous overcurrent



Tap changer overpressure


Fan failure

Trip signals shall be sent to directly trip all circuit breakers (three sides) through main trip relay or sent to simultaneously trip through main and backup protection functions of transformer

Unit transformer:

Differential


Restricted & standby earth fault

Transformer overload

Overcurrent and earth fault



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Fan failure

Trip signals shall be sent to directly trip all circuit breakers (three sides) through main trip relay or sent to simultaneously trip through main and backup protection functions of transformer

Note: All above protection functions shall be duplicated and supplied by different manufacturers unless the manufacturer can offer substantially different protection relay philosophies for the duplicate protections and no common mode failure can occur. Single point protection devices, such as Buchholz relays need only to have their trip signalling duplicated.

Distribution Transformer (Dry Transformer-Auxiliaries):

Winding temperature

Overcurrent and earth fault

Undervoltage

Differential protection for low transformer greater than or equal to 2MVA

MV incomers and interconnectors:

IDMT overcurrent & earth fault

Synchrocheck relay

Feeders (MV & LV):

IDMT & instantaneous overcurrent & earth fault

6.6kV Switchboards:

Busbar undervoltage/ overvoltage

Busbar differential protection

Busbar earth fault

Back-up breaker fail

6.6kV Motors 1MW:

Differential

Undervotage

Switching surge protection

Instantaneous overcurrent and time delayed earth fault

Thermal overload

Single phasing and unbalanced loading

Stalling

Number of starts per hour


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Other 6.6kV motors:

Thermal overload

Undervoltage

Switching surge protection

Instantaneous overcurrent and time delayed earth fault


Stalling


400 V Motors equal to or above 110 kW:

MCCB, CFS unit or fuses

Undervoltage

Thermal overload

Instantaneous overcurrent & core balance earth fault


Stalling


400 V Motors below 110 kW:

MCCB, CFS unit or fuses

Undervoltage

Thermal overload

Time delayed core balance earth fault

400 V Switchboards:

IDMT overcurrent & earth fault synchrocheck relay on incomers & interconnectors

IDMT & instantaneous overcurrent & earth fault on feeders other than motor feeders

IDMT & instantaneous overcurrent & earth fault MCC incomers

Undervoltage on all sections

Note: Use 400V for motors rated < 200kW

Use 6.6kV for motors rated >= 200kW

6.3.4.2 Design Criteria for Generator Protection Scheme

(1) General Requirements

Two generator protection schemes namely No. 1 and No. 2 protection schemes for the generator, generator transformer, excitation transformer and unit transformer shall be provided.


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The No. 1 and No. 2 numerical generator protection systems shall have the following main features:

(a) Complete galvanic and reliable separation of internal processing units from the measurements, control and supply units of the system, with screened analog inputs, output modules and DC converter;

(b) Insensitive to VT and CT errors, external fault or through fault conditions, magnetizing in-rush current and CT saturation arising due to large DC components.

(c) Complete digital measured value processing up to the trip decisions for the circuit breakers;

(d) Calculation and display of operational measured values.

(e) Relay setting operation menu-assisted capable via a connected personal computer with menu-guided software which shall permit the following to be carried out;

(i) Setting of parameters;

(ii) Display of measured values;

(iii) Display of events, their acknowledgment and print-out;

(iv) Recording of settings, hence a permanent record of relay settings;

(v) Testing of system.

(f) Storage of fault data, storage of instantaneous values during a fault for fault recording and event recording;

(g) Continuous self monitoring of the hardware and software of the relay and providing remote alarm when a component failure is detected;

(h) A centralised display of the monitored operating conditions of the protected equipment, all alarm conditions and detected faults which would assist the operation of the protected plant.

(i) Communication with central control and storage devices via serial interface or other communication system is possible.

(j) A library of software protection functions shall be provided to fulfil the protection and auxiliary functions so that it is possible at anytime to change and program on Site other protection functions from the library of software functions to cover other possible redundancy requirements when one protection system is taken out of service for operational reasons.

(k) Built-in output relay units with tripping matrix and alarm functions.

(l) Tripping matrix for external trip signals.

(2) Minimum Protection Functions for the Generator Protection Scheme

(a) No. 1 numerical generator protection scheme (No. 1 Scheme) shall include the following protection functions:

Generator three-phase differential


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Generator stator earth fault for protection up to 95% stator winding against a single phase to earth fault

Negative phase sequence

Field failure

Field earth fault protection

Loss of excitation

Reverse power (relay 1 with definite time delayed)

Generator thermal overloads (three-phase)

Generator transformer three-phase differential

Generator transformer restricted earth fault

Unit transformer three-phase differential (the zone of protection shall include the HV terminals of the unit transformer up to the protection CT’s current transformers located at the 6.6kV main incoming circuit breaker at 6.6kV unit switchboard)

The 19kV definite time earth fault (to be fed from the open delta VT located at the phase isolated bus via a normally closed auxiliary switch contact of the 19kV GCB)

This protection is to protect the 19kV transformer zone from earth faults when the generator is disconnected from the system. The auxiliary contact interlock is necessary to prevent the transformer zone from spurious tripping when an earth fault occurs on an in-service generator

Excitation transformer three-phase differential.

(b) No. 2 numerical generator protection scheme (No. 2 Scheme) shall provide the following protection functions:

Overall unit three-phase differential (generator, generator transformer and unit transformers).

Neutral displacement (time delayed trip).

Negative phase sequence.

Field failure.

Loss of excitation

Reverse power (relay 2 with definite time delay).

Unit transformer three-phase overcurrent (instantaneous and inverse definite minimum time delayed (IDMT) characteristics). This protection shall co-ordinate with the thermal capability of the transformer and the overcurrent protection provided at the 6.6kV main incoming circuit breaker.


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Unit transformer neutral earth fault. This protection shall co-ordinate with the earth fault protection provided at the 6.6kV main incoming circuit breaker.

Excitation transformer three-phase overcurrent (instantaneous and IDMT characteristics). This protection shall co-ordinate with the thermal capability of the transformer and generator rotor.

Generator transformer overfluxing protection. This is volt/hertz protection for possible over-excitation condition during start-up and shutdown operation. It shall be co-ordinated with the transformer excitation curves.

The 19kV definite time earth fault (to be fed from the open delta VT located at the phase isolated bus via a normally closed auxiliary switch contact of the 19kV GCB). This protection is to protect the 19kV transformer zone from earth faults when the generator is disconnected from the system. The auxiliary contact interlock is necessary to prevent the transformer zone from spurious tripping when an earth fault occurs on an in-service generator.

(c) No. 1 scheme shall be provided with signals from the following sources and provide the appropriate trip and alarm outputs:

Generator transformer oil flow failure

Unit transformers main tank oil surge/qualitrol devices

Unit transformers tap changer oil surge/qualitrol devices

Automatic excitation regulator failure

220kV switchyard intertrips

6.6kV unit & station switchboard A busbar protection local back-up

6.6kV unit & station switchboard B busbar protection local back-up

Turbine trip relays (with reverse power relay interlock).

And other protection recommended by transformer manufacturer.

(d) No. 2 Scheme shall be provided with signals from the following sources:

Generator transformer oil flow fail (duplicated)

Generator transformer main tank oil surge/qualitrol device

Generator transformer tap changer oil surge/qualitrol device

Generator transformer diverter switch pressure surge

Automatic excitation regulator failure

220kV switchyard intertrips.

6.6kV unit & station switchboard A busbar protection local back-up

6.6kV unit & station switchboard B busbar protection local back-up


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Turbine trip relays (with reverse power relay interlock)

And other protection recommended by transformer manufacturer.

(3) Tripping Requirements for Unit Protection Scheme

Protection multi-trip latched relays shall be provided for each of No. 1 and No. 2 Schemes which shall provide trip signals to the following equipment:

(a) Boiler Protection System (BPS)

(b) Turbine Protection System (TPS)

(c) Excitation control system

(d) Generator field circuit breaker

(e) Burner Management System (BMS)

(f) Unit transformer circuit breakers

(g) 220kV switchyard inter trip

(h) GCB

(i) Generator transformer oil pump (only if the generator transformer differential, overall differential, generator transformer restricted earth fault,generator transformer oil surge/qualitrol protection, or 6.6kV switchboard busbar protection operated)

(j) Generator fault recorder trigger.

6.3.4.3 Design Criteria for 220/6.6-6.6kV Station Transformer Protection

(1) Station transformer protection scheme shall include the following protection functions:

(a) Station transformer three-phase, differential protection: the zone of protection shall include the 220kV terminals of the transformer; 220kV switchgear; and its 6.6kV terminals of transformer.

(b) Station transformer three-phase overcurrent protection (instantaneous and IDMT characteristics) on the 220kV terminals of the transformer. This protection shall co-ordinate with the thermal capability of the transformer and the overcurrent protection provided at the 6.6kV incoming circuit breaker at 6.6kV station switchboard.

(c) Station transformer neutral earth fault protection in the neutral of the 220kV winding. This protection shall co-ordinate with the earth fault protection provided at the 220kV circuit breaker at 220kV switchyard.

(d) Station transformer restricted earth fault protection for the 220kV winding.

(e) Station transformer neutral earth fault protection in the neutral of the 6.6kV winding. This protection shall co-ordinate with the earth fault protection provided at the 6.6kV main incoming circuit breaker at 6.6kV station switchboard.


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(2) The station transformer protection shall incorporate signals from the following sources:

(a) 220/6.6-6.6kV station transformer Buchholz and oil surge device

(b) 220/6.6-6.6kV station transformer tapchanger protection (overpressure, etc.)

(c) 220/6.6-6.6kV station transformer oil flow failure

(d) 6.6kV station switchboard busbar protection local back-up (duplicated).

(e) Any other protection recommended by transformer manufacturer

(3) Protection multi-trip latched relays shall be provided for each of No. 1 and No. 2 station transformer protection schemes which shall provide trip signals to the following equipment:

(a) 6.6kV incoming circuit breaker at 6.6kV station switchboard.

(b) 220kV switchyard inter trip.

6.3.4.4 Design Criteria for 6.6kV Distribution System (Unit Auxiliary and Station)

(1) The incoming supplies from the station and unit auxiliary transformers to their corresponding 6.6kV switchboards shall be provided with three-phase overcurrent protection (IDMT characteristics) and earth fault protection.

The three-phase overcurrent protection settings shall be coordinated with the three-phase overcurrent protection provided on the HV side of the station and unit auxiliary transformers to ensure discriminative tripping and back-up protection. Similarly, the earth fault protection settings shall be coordinated with the neutral earth fault protection on the LV side of the respective transformers.

In addition, both of the three-phase overcurrent and earth fault protection shall be coordinated with outgoing circuit protection.

(2) The Interconnector circuits between 6.6kV switchgear switchboard (station services and unit auxiliary) shall be provided with three-phase overcurrent protection (IDMT characteristics) and earth fault protection.

The three-phase overcurrent protection and earth fault protection settings on the interconnector circuits shall be coordinated to ensure tripping of these interconnector circuits prior to the tripping of the incoming circuit breaker of the station switchboard or unit switchboard.

In addition, both of these three-phase overcurrent and earth fault protection shall be coordinated with the protection provided on the switchboard outgoing circuits.

(3) Feeder circuits to load centres, and to step-down transformers associated with the variable speed drives shall be provided with three-phase overcurrent protection (instantaneous and IDMT characteristics) and earth fault protection (instantaneous and IDMT characteristics). The settings on these types of protection shall ensure co-ordination and discrimination with the protection provided in the load centres and also with the thermal capability of the protected transformers.

(4) Each 6.6kV unit auxiliary switchboards shall be provided with busbar protection.


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The busbar protection shall also provide trip signals to associated interconnector circuits and all circuits connected to the 6.6kV unit switchboard.

(5) Each 6.6kV unit auxiliary switchboard supplying one or more motors shall be provided with undervoltage protection. This undervoltage protection shall initiate load shedding to prevent connection of all the motor loads simultaneously on the return of AC power source to the 6.6kV bus.

(6) If there are any variable speed drives connected to the 6.6kV switchboards (unit auxiliary or station), the need for protection from harmonics that will be generated from the static power unit forming part of the variable speed drive units will need to be evaluated. Consideration for 6.6kV harmonic filters and their effect on the performance of the unit auxiliary and station transformers shall be evaluated and provided if required.

(7) Each section of the 6.6kV station switchboard shall be provided with busbar protection.

The busbar protection shall also provide trip signals to associated interconnector circuits, incoming station transformer and all outgoing circuits.

(8) If there are motors connected to any section of 6.6kV station switchboard, that section of 6.6kV station switchboard shall be provided with undervoltage protection. This undervoltage protection shall initiate load shedding to preventconnection of all the motor loads simultaneously on the return of AC power source to the 6.6kV bus.

6.3.4.5 Design Criteria for 400V Distribution System (Unit Auxiliary, Emergency, Station

Auxiliary)

(1) All the 6.6kV/400V unit auxiliary transformers, emergency transformers, and the 6.6kV/400V station auxiliary shall be provided with winding temperature detector for alarm. The neutral of the 400V windings shall be provided with the inverse time neutral earth fault protection. This neutral earth fault protection shall be coordinated with the largest fuse and earth fault protection on feeders connected to the load centre.

The incoming supplies from the 6.6kV/400V station auxiliary & station emergency and unit auxiliary transformers to their corresponding 400V switchboards shall be provided with three-phase overcurrent protection (IDMT characteristics) and earth fault protection.

The three phase overcurrent protection settings shall be coordinated with the three phase overcurrent protection provided on the 6.6kV side of the station auxiliary, emergency transformers, and unit auxiliary transformers to ensure discriminative tripping and back-up protection. Similarly, the earth fault protection settings shall be coordinated with the neutral earth fault protection on the 400V side of the respective transformer.

In addition, both of the three phase overcurrent and earth fault protection shall be coordinated with the protection provided on outgoing circuits.


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(2) The interconnector circuits between 400V switchboard (station auxiliary and unit auxiliary and emergency) shall be provided with three phase overcurrent protection (IDMT characteristics and earth fault protection).

The three phase overcurrent protection and earth fault protection settings on the interconnector circuits shall be coordinated to ensure tripping of these interconnector circuits prior to the tripping of the incoming circuit breakers of the 400V station switchboard.

In addition, both of these three phase overcurrent and earth fault protections shall be coordinated with the protection provided on outgoing circuits.

(3) The load centre Motor Control Centre (MCC) feeder circuits shall be provided with three phase overcurrent protection (instantaneous and IDMT characteristics) and earth fault protection (instantaneous and IDMT characteristics). The settings on these types of protection shall ensure co-ordination and discrimination with the protection provided on outgoing circuits in the load centres.

(4) The essential section of the 400V unit auxiliary switchboard shall be provided with undervoltage protection. On detection of undervoltage, it shall trip the normal power source breaker and automatically transfer to an alternative power source (from 6.6kV/400V emergency transformers) to ensure an uninterrupted supply of power. Also refer to Clause 6.3.1.5.

(5) The non-essential section of each 400V unit auxiliary switchboard shall also be provided with undervoltage protection. This undervoltage protection shall initiate load shedding to prevent connection of all the motor loads simultaneously on the return of AC power source to the 400V switchboard.

(6) If there are any variable speeds drives connected to the 400V switchboard, the need for protection from harmonics that will be generated from the static power unit forming part of the variable speed drive units will be evaluated. Consideration for 400V harmonic filters and their effect on the performance of the unit auxiliary, emergency transformers, and station auxiliary transformers shall need to be evaluated and provided if required.

6.3.4.6 Design Criteria for 400V MCCs (Unit Auxiliary and Station Auxiliary Services)

(1) The incoming feeder circuits shall be provided with three phase overcurrent protection (instantaneous and IDMT characteristics).

(2) Outgoing circuits shall be protected thermally and against short-circuit faults by the following devices:

(a) CFS units

(b) Fixed fuses

(c) Moulded Case Circuit Breaker (MCCB).

6.3.4.7 Drawings and design data

The following drawings and design data shall be provided by the Contractor during the course of the Contract.

(a) Protection design calculations


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(b) Relay settings

(c) Full AC/DC schematics and tripping sequence block diagram for the generator protection

(d) Overall protection co-ordination diagram

6.3.4.8 Electrical Synchronizing Facilities

One set of automatic and manual synchronizing equipment will be provided for each generating unit. Synchrocheck relays must be supplied for all breakers where asynchronous conditions can occur at normal start up.

6.3.4.8.1 Synchronizing Equipment

In order to allow manual synchronizing, each unit will have the following hardwired equipment as part of the unit control desk.

(a) Dual voltmeter

(b) Dual frequency meter

(c) Synchroscope

(d) Circuit breaker close pushbutton

The circuit breaker close button will be “hard-wired” to the circuit breaker close coil via the unit synchronizing panel to minimize the time delay between its operation and the closure of the circuit breaker.

The automatic synchronizing equipment and check synchronizing equipment will be located at the generator protection panels of the generating unit and will include:

(a) Auto synchronizer.

(b) Manual check synchronizing relay

(c) Check synchronizing guard relay

(d) Circuit breaker and hardwired panel equipment selection relays (driven by ICMS).

The circuit breaker close output of the automatic synchronizer will be “hard-wired” to the circuit breaker close coil to minimize the time delay between the synchronizer’s operation and the closure of the circuit breaker.

The guard relay is associated with the check synchronizing relay. It prevents the check synchronizing relay from closing the circuit breaker when conditions are acceptable. If the operator has pressed and held the button before the acceptable conditions are met, it forces the operator to make the decision to close, rather than allowing the check synchronizing relay to decide.

The check synchronizing relay shall have facilities to allow closure if voltage is absent on one side.

Selection of a particular circuit breaker for synchronizing will be made via the ICMS.


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6.3.4.8.2 Redundancy

Redundancy in automatic synchronizing circuits will be provided by a correct selection of auto-synchronizing equipment as follows:

Either

Two automatic synchronizer functions or two check synchronizing functions are contained in the one relay case. Each automatic synchronizer will be checked by a check synchronizing function and operation of either synchronizer will close the circuit breaker.

Or

Two separate relays and each relay shall have automatic synchronizing function and a check synchronizing function. The operation of either synchronizer will close the circuit breaker.

6.3.4.8.3 Manual Synchronizing

Manual synchronizing will be available for the following circuit breakers:

6.6kV unit - station tie breakers

19kV GCB

6.6kV unit transformer output breakers

6.6kV station transformer output breaker.

6.3.4.8.4 Automatic Synchronizing

Automatic synchronizing facilities will be provided for the 19kV GCB, the 220kV circuit breakers, but not for the 6.6kV circuit breakers. Lack of provision of automatic synchronizing at the 6.6kV level is because under normal auxiliary system configuration, where the unit is connected to the common 220 kV switchyard, changes to turbine governor set point and generator excitation set point will not be able to significantly change the voltage magnitude or phase angle on either side of an open circuit breaker. Consequently automatic synchronizing, which requires control of these variables cannot be used.

6.3.5 Cabling Works and Miscellaneous Requirements

6.3.5.1 General

The Contractor shall also provide complete items including but not limited to the followings:

(1) Cabling works for the entire power station. This includes a provision of cable management system as outlined in Volume 2. In the remote areas such as CW area, coal handling Plant area, etc, the Contractor may include the cabling works for these areas under the work packages for those particular Plants. However, the Contractor will have to include in the contract price all costs for all necessary cabling works required for the safe and reliable operation of this power station. All cabling works have to meet the requirement of Volume 2.


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(2) All 400V miscellaneous switchboards including the turbine actuator boards, boiler actuator board, sootblowers, etc, required for the safe and reliable operation of this power station. All Works have to meet the requirement of Volume 2.

(3) All miscellaneous power and lighting required for the safe and reliable operation of this power station. This includes the normal lighting, emergency lighting, exit warning sign, distribution boards, etc. All Works have to meet the requirement of Volume 2.

(4) All cathodic protection and lightning protection for the safe and reliable operation of this power station. All Works have to meet the requirement of Volume 2.

(5) Earthing protection for all electrical items for the safe and reliable operation of this power station. All Works have to meet the requirement of Volume 2.

(6) All other electrical items for the safe and reliable operation of this power station. All Works have to meet the requirement of Volume 2.

(7) Fire and smoke stopping system for the entire power station. All Works have to meet the requirements of Volume 5.

6.3.5.2 Information to be provided

The following Drawings and information shall be provided by the Contractor during the course of the Contract.

(a) Single line diagrams of all 400V switchboards

(b) Layout of all 400V switchboards

(c) Layout of normal lighting, emergency lighting and emergency warning exit signs

(d) Earthing layout and design calculation

(e) Design calculation for the cathodic protection and lightning protection

(f) Cable management system

(g) Cable termination diagrams where required.


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6.4 DC SYSTEM

6.4.1 General

(1) Relevant Standards:

IEEE 485-1997, IEC 60896

(2) System Configuration:

The DC auxiliary system is depicted in appropriate drawing in Volume 9 Drawings.

The DC system shall comprise two (02) nominal 220V DC station systems for two generator units with 2 x 100% batteries, and 2 x 100% battery chargers for each system.

Each 100% battery should be capable of supplying the emergency loads that apply when the normal AC power system has failed, or when the AC supply to the battery chargers has failed.

The minimum acceptable level of reliability in the system is that it should meet its full operational requirements with one battery out of service. Batteries shall be rated such that one battery can meet the requirements of the generating unit for a minimum period of 30 minutes in the event of a total loss of AC supplies.

This protects the security of the Plant in the event of a battery failure and permits off-line boost charging, discharge testing etc.

Each battery will be housed in a separate dedicated room incorporating appropriate ventilation, showers, floor treatment and other safety features.

Each 100% battery charger shall be capable of supplying the continuous and intermittent loads associated with two generating units while in the ‘float' mode of operation.

In addition each charger when off-line shall be able to supply the necessary current to enable boost charging of a battery.

During periods of intermittent loads, or when the battery is taking the full emergency load (i.e. during the safe shutdown of a unit) the DC system voltage shall not fall below a value which is injurious to any of the equipment connected to the DC system. In any event the DC system voltage shall not fall below 189.0 volts, during the duty cycle following the complete loss of AC supply, with one battery in service.

(3) The 220V system will serve the following:

(a) DC supply for safe shutdown of turbine and boiler auxiliaries such as the lubricating oil pumps etc. in the immediate aftermath of a total loss of normal AC supplies;

(b) Controls and instrumentation equipment;

(c) Control of switchgear except HV switchyard which will have separate batteries.


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(d) Uninterruptible AC power supply (UPS) system

(e) Generator protection

(f) Transformer yard protection

(g) Generator field flashing

(h) DC emergency lighting system.

(4) The Contractor shall submit full details of proposed safe shutdown/emergency loads for approval by the Employer.

The DC system shall be designed with the following minimum requirements:

(a) Two radial feeders to each load to allow for maintenance on a switchboard or a feeder, without loss of availability of a supply.

(b) Battery installation in accordance with the safety provisions of the latest international standards.

(c) Routine off-line maintenance capacity testing of a battery, in accordance with international standards whiles the second battery remaining in service supplying the requirements of the generating unit.

(d) The ripple to be maintained at less than 2%.

(e) Battery shall be sized in accordance with IEEE Standard 485-1997 and based on the duty cycle diagram, showing the current versus time characteristic of the DC system, following the loss of AC supply, with one battery in service. The duty cycle diagram shall be submitted to the Employer for approval prior to manufacturing.

(f) The sizing of the battery shall use an end voltage of 1.75 volts/cell and a temperature of 25oC with account being taken of the relatively high ambient of 30oC.

(g) In order to minimize the voltage drop on the DC system and to DC standby motors, series resistance starters shall be used which limit the starting current to twice the full load current.

(h) Voltage drop in all elements including cables shall be taken into account so that the DC standby motors terminal voltage does not fall below 80% of the DC nominal system voltage during starting.

6.4.2 Batteries, Chargers, Inverters and UPS Modules

(1) Batteries

The batteries shall comprise cells of the valve regulated lead acid (VRLA) batteries complying with IEC 60896-21 and IEC 60896-22

The batteries shall be sized in accordance with IEEE Standard 485-1997.

A performance test of the battery capacity shall be included as part of the commissioning procedure.


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(2) Battery Chargers

Two battery chargers are required and each battery charger shall be of the constant potential type. Each battery charger shall be sized to supply the DC requirements of the inverter, the recharging current of the batteries as well as supplying the standing DC loads under all system conditions.

The battery chargers shall be suitable for operating in parallel with the batteries, and operating on a stand alone basis with the batteries disconnected and the battery chargers supplying the standing load.

(3) Inverters and UPS Modules

The 230V AC UPS supply system should be inverter fed from the 220V DC system as presented in appropriate drawing in Volume 9 Drawings.

The 230V AC UPS system will service:

(a) Fire protection and monitoring

(b) Control equipment

(c) Turbine supervisory equipment

(d) Unit operator workstation

(e) Engineering workstation.

The 230V AC UPS system will comprise two inverter/static switch modules, connected in a parallel redundant mode, such that they normally share the load. Upon the failure of one module, it will automatically shut down and the other module will take the full load.

This system allows either module to be taken out of service for maintenance, leaving the remaining module to supply the load.

Uninterruptible 230V AC power supply (UPS) system:

The 230V AC UPS supply system is inverter fed from the 220V DC system as presented in appropriate drawing in Volume 9 Drawings.

The 230V AC UPS system will service PCR lighting/emergency lighting.

The 230V AC UPS system will comprise two inverter/static switch modules, connected in a parallel redundant mode, such that they normally share the load. Upon the failure of one module, it will automatically shut down and the other module will take the full load.

This system allows either module to be taken out of service for maintenance, leaving the remaining module to supply the load.

6.4.3 Requirements for Battery Rooms

The battery room shall comply with the requirements of IEC 60079.

6.4.4 Battery Installation Safety Requirements

The battery installation shall comply with the requirements of IEC 60079 or equivalent


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The emphasis at all times shall be on providing a safe installation.

6.4.5 Drawings to be provided by the Contractor

The following Drawings shall be provided by the Contractor during the course of the Contract.

(1) Detailed layout of the battery room showing important dimensions including distances between of batteries and door openings.

(2) Detailed layout of 220V DC switchboards.

(3) Detailed layout of DC switch room.

(4) Detailed layout of inverter, UPS modules and the central output cubicle.

(5) Single line diagrams of the 220V DC and 230V AC UPS systems.

(6) Details of safety signs for battery room.


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6.5 ELECTRICAL PLANT

(Refer to Appendices 3 & 4 for further specific requirement and arrangement details. The appendices take precedence over these sections contents.)

6.5.1 Phase Isolated Busbar (PIB) Systems

This Work should included the manufacture, delivery to, erection, testing and commissioning of a set of phase isolated busbars and associated Works for a 600MW generator at the Project.

The equipment shall comply with the following standards and this specification:

IEEE C37.23 - Standard for Metal-Enclosed Bus

IEC 60071-1 - Insulation co-ordination - Definitions, principles and rules

IEC 60071-2 - Insulation co-ordination - Application guide

BS 159 - Specification for High Voltage Busbars and Busbar Connections

BS 1977 - Specification for High Conductivity Copper Tubes for Electrical Purposes

BS 2898 - Specification for Wrought Aluminum and Aluminum Alloys for Electrical Purposes - Bars, Extruded Round and Sections

IEC 60168 - Tests on Indoor and Outdoor Post Insulators of Ceramic Materials or Glass

IEC 60137 - Bushings for Alternating Voltages above 1000V

IEC 60076 - Power Transformers – all relevant parts

IEC 62271-102 - Alternating Current Disconnectors (Isolators) and Earthing Switches

IEC 60044 - Instrument transformers

IEC 60060-1 - High Voltage Test Techniques - General Definitions and Test Requirements

IEC 60060-2 - High Voltage Test Techniques - Measuring Systems

ISO 9606-2 - Approval Testing of Welds - Fusion Welding -Aluminum and Aluminum Alloys

ISO 3777 - Radiograph Inspection of Resistance Spot Welds for Aluminum and its Alloys - Recommended Practice

ISO 2437 - Recommended Practice for the X-ray Inspection of Fusion Welded Butt Joints for Aluminum and its Alloys and Magnesium and its Alloys 5 to 50 mm


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thick.

6.5.1.1 Extent of Supply

The plant shall consist of the following main components for each unit:

(1) One complete three phase set of phase isolated busbars with all supporting insulators and enclosing ductwork. Also a complete set of supports, frameworks and brackets. The set of busbars shall consist of the following sections.

(i) The main busbars between the generator and its generator transformer including the flexible connections to the generator terminal stalks and to the terminals of the generator transformer.

(ii) The generator star point busbar including the flexible connections to the generator neutral terminal stalks.

(iii) Unit transformer tee off, including the flexible between the busbars and the high voltage transformer terminals.

(iv) The excitation transformer tee off, including the flexible between the busbars and the transformer terminals.

(v) The voltage transformer connections from the main busbars to the voltage transformer cubicles.

(2) Three sets of current transformers and associated equipment; one set on the main busbars, one set on the generator neutral and one set on unit transformer tee off.

(3) Two sets of voltage transformers and voltage transformer cubicles.

(4) One earthing switch per voltage transformer set with key interlocking on the generator voltage transformer.

(5) One neutral earthing transformer.

(6) One neutral earthing transformer secondary resistor.

(7) One marshalling cubicle for all secondary wiring terminals and current transformers overvoltage protection equipment and auxiliary apparatus.

(8) Connections between the following items of Plant:

(i) Between the star point of the generator and the neutral earthing transformer. Between the neutral point of the generator voltage transformers and the star point of the generator.

(ii) Earthing connections from all components of the Plant supplied under this Contract to the earthing system.

6.5.1.2 Busbars

(1) The busbars shall be of the air insulated, self-supporting, phase isolated type enclosed in weatherproof metal ductwork and shall be naturally cooled. This shall be achieved with an air delivery and drying system with a delivery rate matched to a controlled overall bus system air leakage rate. The delivery capacity shall be


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sufficient to maintain positive pressure at all times. Sight-glass ground level water collection points will be provided as a means of monitoring dryness.

(2) The busbars and ductwork from the foundation block, across the floor of the turbine house, through the turbine house wall to the transformer terminals, etc., shall be supported by means of structures, frameworks and brackets so as to form a rigid structure.

(3) The Contractor shall provide weather-proof sealing plates where the ductwork passes through the turbine house wall.

(4) The Contractor shall prevent the transmission of building vibration to the ductwork as well as allowing for electrical isolation of the ducting.

(5) In any part of the busbars or busbar enclosure the maximum temperature rise shall not exceed 50ºC above the ambient conditions.

6.5.1.3 Electrical Characteristics

(1) The whole of the busbars and connections shall have a current rating of 12000A. These and all following fault levels are based on a generator line voltage of 19kV. For any higher generator line voltage all fault currents will have to be adjusted by the Contractor.

(2) The branch phase-isolated busbars between the main phase-isolated busbars and the unit transformer (19kV/6.6-6.6kV) is required to have a current rating of 2000A. For any different generator line voltage all fault currents will have to be adjusted by the Contractor.

(3) The branch phase-isolated busbars between the main phase-isolated busbars and the excitation transformer is required to have a current rating of 2000A. For any different generator line voltage all fault currents will have to be adjusted by the Contractor.

(4) All conductors and conductor details, including the neutral conductor shall be insulated for a lightning impulse withstand voltage as per IEC 60071-1 and IEC 60071-2.

(5) The Contractor shall provide all the details as set out in Volume 12 Technical Schedules.

6.5.1.4 Construction

(1) Busbars shall be of copper, aluminium or aluminium alloy and shall comply with the requirements of BS 159 and BS 1977 or BS 2898 as required.

(2) Allowance shall be made for expansion and contraction of the conductor and housing due to normal or short-circuit temperature rises. The use of sliding joints in conductors will not be considered. Conductors may be joined together leaving a suitable expansion clearance and the electrical connection made by means of bolted flexible conductors.

(3) The connection point to the generator, unit and excitation transformer busbar interconnections shall be of the flexible type and these flexible connections shall be removable for isolation purposes.


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(4) The generator neutral current transformer, the primary terminals of the neutral earthing transformer, the neutral cable and bushing and all high voltage connections between these parts shall be situated in a weatherproof aluminium casing, the side panels being removable to allow access to the inside of the casing.

(5) Busbar adaptor plates shall be provided at the terminal points to take up possible minor misplacement during erection. The adaptor plates shall be drilled on Site.

(6) The joining of busbar sections shall be carried out by either bolting or welding. If bolted, the bolting details shall not be subject to electrolytic action.

(7) All bolts and nuts shall be locked after erection. For electrical conducting connections all bolts, nuts and washers shall be of non-magnetic stainless steel grade 8.7. Belleville type washers shall be used at joints on the main connections. Belleville washers shall comply with Clause 6.5.1.9.

(8) All jointing surfaces to copper busbars, intermediate or adaptor plates and flexible conductors shall be silver plated.

(9) All jointing surfaces on aluminium busbars, intermediate or adaptor plates shall be greased with Penetrox or other approved contact compound and wire brushed before bolting up. Different method may be used only if approved by the Employer.

6.5.1.5 Ductwork

(1) It is preferred that the ductwork be of all welded aluminium construction. Inspection holes must be provided for maintenance purposes such as replacement of insulators, and checking of joints between sections of busbars.

(2) The ductwork is to be pressurized to a level sufficient to prevent the ingress of moisture and foreign particles into the busduct. The Contractor shall provide all details in relation to the requirements of the pressurized air system during detailed design.

(3) Provision shall be made to ensure that water leaks from any source will not accumulate in the ductwork. Drains shall be provided at all low points of the ductwork system i.e. voltage transformer cubicles, excitation transformer, unit auxiliary transformer and generator transformer. Drains shall be of the sealed type and description shall be given of the provisions made to maintain pressure within acceptable limits. At each drainage location the drains from each phase shall drain into a single drainage container located at ground level. The drainage container shall be made from glass or UV protected plastic and fitted with a drain valve.

(4) The ductwork shall be vermin proof.

(5) The enclosure around the generator terminals shall be so arranged that the current carrying flexible connections and the bushing connections are easily accessible for inspection and maintenance.


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6.5.1.6 Aluminium Welding

(1) Aluminium welding shall comply with all clauses of ISO 9956-4, ISO 10043 and ISO/TR 11069.

(2) All butt welds shall be complete penetration butt welds. Backing bars shall be close fitting, centred at the joint and of sufficient thickness to avoid burn through. Typical joint details shall be submitted by the Contractor to enable the Employer to designate joints for non-destructive testing.

6.5.1.7 Support Structures, Framework and Brackets

(1) Supporting structures may be of ferrous or non-ferrous construction. Welded construction is preferred.

(2) They shall be designed to withstand, with ample margin, the thermal stress arising from the normal full load current and the mechanical and thermal stresses arising from the maximum fault currents.

(3) It is preferred that no support be taken from the generator block. However, if the design of the ducting is such that this is necessary, special provision shall be made for preventing the transmission of vibration from the generator block to the ducting. The design of anti-vibration mountings shall be submitted to the Employer for approval.

(4) The temperature of any portion of the supports, etc., (excluding the ductwork) shall be raised by not more than 40C above ambient temperature, measured by thermometer when the bus is carrying full rated current. If necessary, the Contractor shall provide suitable magnetic screens to ensure that this temperature rise is not exceeded.

6.5.1.8 Busbar Support Insulators

(1) Busbar support insulators shall be of the outdoor type.

(2) The Contractor may offer either porcelain or epoxy resin type insulators.

(3) The Contractor shall provide detailed evidence in relation to the nominated insulator manufacturer for each of the following items:

(a) Previous experience in manufacturing these insulators (detailing respective clients).

(b) Facilities available for testing to prescribed standards (i.e. type test etc.). If the manufacturer is unable to conduct certain tests, the Contractor shall nominate the venue for such testing.

6.5.1.9 Dished Spring ("Belleville") Washers

(1) All Belleville washers shall be manufactured from suitable spring steel so that the finished product will have the mechanical properties as indicated below.

Nominal diameter M16 M12 M10

Outside diameter (mm) 45 max. 45 max. 35 max.

Total height (mm) 6.5 max. 6.5 max.


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(Thickness + dish dimension)

Flattening load (kN) 30,000 22,000 15,000

+2,000 +2,000 +2,000

(2) To avoid stress concentration, the internal and external edges shall be rounded. The washers shall be suitably heat treated in order to avoid hydrogen embrittlement. After the fabrication and heat treatment, all washers shall be subjected to a suitable cleaning process to completely remove any grease, rust, scale, dirt, etc.

(3) Immediately after cleaning, all washers shall be zinc plated.

6.5.1.10 Current Transformers

(1) Protection and metering CTs shall comply with requirements of Volume 2.

(2) All CTs shall be of the toroidal type suitable for installation at the following locations:

(a) In the ductwork between the generator and GCB, as close as possible to the GCB.

(b) On the generator neutral busbar terminals.

(c) In the unit transformer busbars.

The secondary windings of all CTs shall be brought out to suitable terminals via isolating links for testing.

(3) Adequate supports shall be provided for all CTs and such supports shall not use in any way the main busbar, generator terminals nor the terminals of the earthing transformers. The Contractor shall include in their drawings details of the proposed method of mounting CTs.

(4) All protection and metering CTs shall be insulated for the system highest voltage. This system is non-effectively earthed.

(5) Interposing CTs shall be mounted adjacent to the main CTs and the leads between them shall be joined by brazing. Each interposing CT cubicle shall contain an anti-condensation heater.

(6) An interposing CT shall not be used in conjunction with a metering CT.

(7) Test links shall be connected into the CT secondary circuits so that only the external burden is subject to isolation by these links.

6.5.1.11 Voltage Transformers

(1) VTs shall comply with the requirements of Volume 2.

(2) The high voltage neutral of the generator VTs shall be isolated from ground.

(3) The high voltage neutral of the generator transformer VTs shall be brought out from the tanks and connected by means of an approved 18/30kV XLPE cable in accordance with Volume 2 to the star point of the generator.


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(4) The VTs shall be of the oil immersed, sealed non-breathing type mounted in sheet steel tanks.

(5) The VTs shall consist of single phase, fully isolated metal clad units, comprising single phase transformers for each phase, connected up so as to form a three phase, star connected bank and shall be mounted in VT cubicles.

(6) The Contractor may offer arrangements consisting of either three single phase metal clad units (i.e. one per phase) or three units combined into a single compartmented tank: the star point connections in this case being made via bushings through the compartment walls. The compartment walls shall be of metal and each compartment shall be entirely scaled off from the adjacent compartments.

(7) VT cubicles shall be provided with two phase isolated compartments for each phase.

(8) One compartment shall house the VT truck for that phase and the second compartment may be shared at a later stage by a surge diverter capacitor.

(9) The earthing switch (refer Clause 6.5.1.16) shall be situated in the VT cubicle.

(10) Each compartment shall be fitted with front and rear hinged access doors. The Contractor shall note the clearance available when designing the access doors.

(11) Facility shall be provided for taking oil samples. For this purpose a drain valve shall be installed.

(12) Fire resistant shutters shall be provided which automatically close over the apertures in the busbar chambers and over all primary conductors when the VT is racked out from the busbar. The shutters shall be provided with padlocking facility in the closed position. Padlocking shall be easily accessible with the transformers in the racked out position.

(13) The transformers shall be of the horizontal withdrawable truck type. The arrangement shall be such as to enable the operation of racking out and replacing a transformer to be done with ease by one operator.

(14) Floor rails shall be provided to prevent damage to the floors of the cubicle while the trucks are being withdrawn or replaced. The rails shall be zinc plating to a minimum thickness of 25 microns.

(15) A mechanical locking device shall be provided on each VT truck to secure VTs against accidental movement in both racked in and out positions. It shall be possible to close cubicle doors when VT truck is racked out and the shutters closed.

(16) It is preferred that the high voltage connections to the VTs be of the spring loaded male and female "spout" type. The insulation shall attain the specified lightning impulse withstand level without the use of any ancillary means (e.g. rubber glove). The Contractor shall comment on the method used to maintain contact with the fixed conductors. Alternatives may be proposed but in such case full details shall be included. The Contractor shall submit test certificates with their offer proving their design obtains the required lightning impulse withstand level with the VT in the in service position.


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(17) Each compartment or individual tank shall be provided with an approved gas impulse relay having two normally open contacts, one for tripping and one for computer input. Each gas impulse relay shall be accessible for inspection and gas sampling without withdrawing the truck. Secondary terminals and wiring shall comply with the requirements of Volume 2. The secondary fuses shall be accessible, in safety, with the transformer racked in and in service. It is preferred that connection of the secondary wiring to the fixed part of the cubicle be by withdrawable plug connections. The use of sliding contacts when the VT is racked into position is unacceptable. All secondary wiring shall be brought back to the "CT/VT marshalling cubicle".

6.5.1.12 Generator Neutral Earthing Transformers

(1) Earthing transformers shall be of the single phase distribution type and shall comply with the requirements of all relevant parts of IEC 60076. One transformer for each generator shall be supplied.

(2) The transformers shall be of the air natural cooling type.

(3) The transformers will normally operate without any appreciable voltage on the primary circuit.

(4) The transformers shall comply with the following requirements:

Frequency 50 Hz

Rated voltage Primary: Generator line to line voltage

Secondary: 400V

Cooling AN (Enclosed type)

Tapping Not required

System earthing Effectively earthed on HV and LV sides

Rating 230 kVA for 30 minutes

Impedance 4.5%

HV test voltages Impulse test 125kV peak

Power frequency test 50kV rms 1 min

(5) The secondary terminals of the transformer shall be wired back to the marshalling cubicle.

(6) The transformers shall be mounted within the generator foundation blocks. Wheels are not required on the transformers.

6.5.1.13 Earthing Resistors

(1) The resistors shall be of the continuous strip type, shall be mechanically robust, fireproof and mounted in wall or floor mounting weatherproof enclosures.

(2) The resistors shall comply with the following requirements:

Cooling AN

Frequency 50 Hz


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Resistance 2 ohms

Resistance tolerance +5%

Tappings 0.5 ohms to 2 ohms in 0.1 ohm steps

Power factor 0.95 minimum

Insulation test voltage (1 min. at 50 Hz)

17kV rms

30 minute current rating on each tap:

0.5 ohm - 551 A 1.3 ohm - 212A

0.6 ohm - 460 A 1.4 ohm - 197A

0.7 ohm - 394 A l.5 ohm - 184A

0.8 ohm - 345 A 1.6 ohm - 173A

0.9 ohm - 307 A 1.7 ohm - 162A

1.0 ohm - 276A 1.8 ohm - 153A

1.1 ohm - 251 A 1.9 ohm - 145 A

1.2 ohm - 230 A 2.0 ohm - 138 A

Temperature rise - 300oC maximum

Temperature co-efficient of resistance

: Not more than 12% change at maximum temperature rise

(3) The tappings shall be easily accessible and adjustments shall be made by alterations to a bolted link arrangement.

(4) A connection diagram plate shall be provided showing clearly the relative physical positions of the terminals and their markings, together with a table listing the link connections to be made corresponding to the various resistance values.

6.5.1.14 CT/VT Marshalling Cubicles

A marshalling cubicle for each generator shall house all the secondary wiring terminals required for the whole installation, together with the current transformer’s current test links, voltage test terminals and all auxiliary apparatus.

Terminals of the same function and voltage shall be grouped together.

6.5.1.15 Magnetic Screens

The Contractor shall provide and install, if necessary, shielding (Amortisseur) grids to ensure that the rise in temperature of the reinforcing steel does not exceed 30oC.

Provision shall also be made to ensure that no part of the building steelwork or sheeting (where the busbars pass through the turbine house wall) has a temperature rise exceeding 30oC.


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6.5.1.16 Earthing Switches

(1) Earthing switches shall comply with IEC 62271-102 for indoor type air break, two- position equipment and shall have the following characteristics:

Rated voltage: Generator terminal voltage

Number of poles: Three phases isolated

Rated short time current time: 2s

(2) Each earthing switch shall consist of three single, fully isolated blades, one for each phase, each phase being located in a separate compartment of the associated VT cubicle and coupled together mechanically to form a three phase group.

(3) The operation of the earthing switch shall be by manual operation of a level or handwheel.

(4) The blade’s action shall be positive in their open or closed positions.

(5) A viewing window shall be installed to observe the position of blades without the need to open cubicle doors.

(6) All current carrying parts shall be made of suitable non-ferrous metals and all bolts, nuts, washers, etc., on current carrying parts shall be of corrosion resistant material.

(7) The contacts shall be of copper or similar approved material with a silver plated finish.

(8) The operating mechanism shall have the following features:

(a) The mechanism shall operate the three phases of the earthing switch simultaneously.

(b) The design shall be sufficiently sound to ensure that the reliability of the mechanism is unaffected by long periods of inactivity.

(c) The operating mechanism shall be arranged so that it can be operated by one man. The centre of the operating handle or wheel shall be approximately 1000mm above ground level and the force required to operate the handle shall be not more than 130N.

(d) Provision shall also be made for securing and padlocking the operating mechanism in the open and closed positions. Such lockout facilities shall be accessible to an operator standing at ground level.

(e) A durable and weatherproof label shall be attached to the handwheel or handle to clearly indicate the direction of operation of the handwheel or handle required to open or close the earthing switch.

(f) If a torsional shaft is used to couple the three poles, sliding and universal joints shall be provided to prevent any axial thrust load being applied to the gearbox bearings due to relative movement of the poles and to allow for a reasonable degree of misalignment of the three poles.

(g) If drag links are used to couple the three poles, they shall be arranged to operate under tension only.


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(h) The handle or handwheel shall be finished to smooth contours, free of burrs and adequately spaced from all fixed parts to eliminate hazards to operating personnel. Particular attention is to be paid to hazards introduced by locking facilities that could cause injury to fingers when operating the handwheel.

(9) The earthing switches shall be equipped with a type key interlock system for safe operation the details of which must be approved by the Employer.

(10) Lightning impulse withstand voltage must be the same as PIB.

6.5.2 Generator Circuit Breaker

This Specification calls for the manufacture, delivery and setting to work at Site of a three phase sulphur hexafluoride gas (SF6) GCB. Each single phase unit shall consist of one SF6 gas circuit breaker complete with grounding switch and one isolator (disconnecting switch) complete with grounding switch.

The equipment shall comply with the following standards of this specification:

(1) IEEE Standard C37.013 Standard for AC High Voltage Generator Circuit Breakers Rated on a Symmetrical Current

(2) IEC 62271-100 High Voltage Alternating Current Breaker

(3) IEC 62271-200 AC Metal Enclosed Switchgear and Control gear for Rated Voltage Above lkV up to and including 52kV.

6.5.2.1 Circuit Breaker, Isolator and Grounding Switches - General Description

(1) The breaker shall be comply with IEEE Std C37.013 - Standard for AC High Voltage Generator Circuit Breaker rated on a Symmetrical Current and IEC 62271-100 - High Voltage Alternating Current Circuit Breaker.

(2) The circuit breaker and isolating switch shall be designed for horizontal mounting in the phase isolated busbar system.

(3) Each single phase circuit breaker complete with isolating switch and grounding switches shall be furnished with a separate enclosure to maintain the integrity of the isolated phase bus ducting. The enclosure shall be a rigid self supporting structure fabricated from aluminium and suitable for indoor installation. All contact surfaces shall be silver plated.

(4) The circuit breaker shall be capable of clearing the following faults as well as normal switching duty associated with large steam driven turbine-generator Plant.

(a) Fault in generator or between generator and GCB.

(b) Fault in generator transformer or between generator transformer and GCB.

(c) Fault in 220kV switchyard.

(d) Fault in unit transformer and excitation transformer or between unit transformer, excitation transformer and GCB.

(e) It shall be possible to obtain full isolation including provision of a visible break by the inclusion of a built-in isolating switch associated with the GCB.


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(5) The isolating switch and GCB shall both be provided with their own separate grounding switches. Each grounding switch shall be rated for full fault current closure.

(6) Interlocking (of electrical and mechanical operating systems) is to be provided between the control cabinet and the isolating switch and GCB to ensure that the grounding switches can only be operated when the isolating switch and GCB are locked open and the phase isolated busbars are de-energized.

(7) The isolated phase bus ducting will be naturally cooled. The maximum air temperature rise within the bus duct will not exceed 40oC above the ambient conditions.

(8) The GCB shall be naturally cooled.

(9) Removable panels shall be provided on all equipment to permit access to all working parts for maintenance.

(10) A mechanical locking device shall be provided to permit padlocking the GCB in the open position.

(11) Single phase operation of the three pole assembly shall be prevented.

6.5.2.2 Circuit Breaker Operating Mechanism

(1) The GCB operating mechanism shall operate all three phases of the GCB by means of a single (common) operating rod.

(2) The three phase GCB assembly shall be controlled by one of the following methods:

(a) Hydraulic operating mechanism,

(b) Stored energy spring charged operating mechanism,

(c) A combination of stored energy spring charged / hydraulic operating mechanism.

(3) The following accessories are to be provided:

(a) Mechanical position indicator marked ”I” with a red background for the closed position and “O” with a green background for the open position that are visible externally to the operating mechanism.

(b) Manual mechanical trip, three pole.

(c) Operations counter (one per pole).

(d) Device for manual slow closing and opening during maintenance.

(e) The mechanism and its control circuit shall be such that "pumping" on to a fault cannot occur if the "close" circuit is energized continuously. It shall also be assumed for this purpose that the trip signal may be present before the circuit breaker closes (controlled via a dedicated anti-pumping circuit). The mechanism and its control circuit shall be such that the circuit breaker is trip free as defined in IEC 62271-100.


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6.5.2.3 Trip Coils

(1) Two electrically and magnetically separate tripping mechanisms, each operated by a separate trip coil shall be provided for circuit breaker. If one tripping mechanism fails or fails to operate correctly, it will not prevent the other mechanism from operating correctly.

(2) Trip coils shall be suitable for nominal 220V DC operation and be capable of operating within the voltage range of 176 V to 264V DC

6.5.2.4 Closing Coil

The closing coil shall be suitable for nominal 220V DC operation and be capable of operating within the voltage range of 176V to 264V DC

6.5.2.5 Isolating Switch Operating Mechanism

(1) The isolating switch operating mechanism shall operate all three phases of the isolating switch by means of a single (common) operating rod.

(2) The three phase isolating switch assembly shall be controlled by a 220V DC (±10%) motor driven device.

(3) The three phase isolating switch assembly shall be equipped for emergency manual operation by means of a hand crank


(a) Mechanical position indicated marked ”I” with a red background for the closed position and “O” with a green background for the open position that are visible externally to the operating mechanism.

(b) Key interlocking in the closed and open positions

(c) Interlock to prevent motor operation while isolating switch is being manually operated.

6.5.2.6 Grounding Switch Operating Mechanism

(1) Each three phase grounding switch assembly shall have its own separate operating device.

(2) The grounding switch operating mechanism shall operate all three phases of the grounding switch by means of a single (common) operating rod.

(3) The three phase grounding switch assembly shall be controlled by a 220V DC motor driven device.

(4) The three phase grounding switch assembly shall be equipped for emergency manual operation by means of a hand crank.


(a) Mechanical position indicated marked ”I” with a red background for the closed position and “O” with a green background for the open position that are visible externally to the operating mechanism.

(b) Key interlocking in the closed and open positions


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(c) Interlock to prevent motor operation while grounding switch is being manually operated.

6.5.2.7 Essential requirements

(1) Generator Circuit Breaker

The following parameters are required:

Nominal operating voltage: Generator voltage

Maximum operating voltage: Generator voltage plus 10 percent

Frequency: 50 Hz

Number of poles: 3

Rated continuous current: At least generator rating

Symmetrical breaking current (three-phase): 110 kA (at 19kV)

Asymmetrical breaking current (three phase): Refer IEEE Std. C37.013 Clause 4.9.2.2

Out of phase switching capability: To be agreed between the Employer and Contractor

Short time current (1 second): Equivalent to breaking current

First pole to clear factor: 1.5

Amplitude factor: 1.5

Operating duty cycle: O-1min.-CO -3 min. – CO

Rated short-circuit making current (1 second): Refer IEEE Std. C37.013

Short-Time Current Rating Period: 1 second

Full wave impulse voltage to ground: 125kV peak

Full wave impulse test voltage across contacts 145kV peak

Power frequency test voltage across contacts 60kV

Power frequency test voltage to ground 50kV

Transient recovery voltage To suit system requirements

(2) Isolating switch

The following parameters are required:

Nominal operating voltage Generator voltage

Maximum operating voltage Generator voltage plus 10 percent

Frequency 50 Hz

Number of poles 3

Rated continuous current At least generator rating


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Rated short-time withstand current Refer IEEE Std. C37.013

Rated short-time making current Refer IEEE Std. C37.013

Power frequency test voltage to ground 50kV rms

Full wave impulse test voltage to ground 125kV peak

Power frequency test voltage across contacts 60kV rms

Full wave impulse test voltage across contacts 145kV peak

6.5.2.8 General Design Considerations

(1) It is required that the construction details and the design of the equipment should be such that it will continue in reliable service with a minimum of maintenance. Furthermore, this maintenance should not require that personnel be especially trained and skilled in the details of this particular equipment because unusual or sensitive component designs have been incorporated.

(2) In the assessment of switchgear offered, close attention will be paid to the manner in which the following principles of design have been observed.

(a) All similar mechanical parts are to be strictly interchangeable without special adjustment or individual fitting.

(b) The assembly of parts shall be easy and simple without requiring special skill in adjustment of alignment. This requirement is to be provided by dowels, spigots, counter bores, etc.

(c) The design should be such as to avoid as much as possible the necessity of close tolerances and fits to ensure that the presence of foreign bodies, dust and moisture or the occurrence of high or low temperatures cannot cause any mal-operation.

(d) The performance of the design particularly that of individual component shall be checked not only many times at normal operating conditions, but at conditions above and below normal to establish the limits at which equipment fails to operate correctly, thus establishing the safety margin to allow for variations.

(e) All mechanical parts and linkages shall be robust, requiring a minimum of maintenance.

(f) Operating forces available from electrical and mechanical sources should be a suitable multiple of and where possible may times the forces required for functioning under designed conditions to ensure beyond any doubt that all elements will operate correctly and reliably for an indefinite period under minimal maintenance attention, most normal service conditions, and taking into account the variations in manufactured materials, workmanship and tolerances.

(g) When components of well-tried designs but with lower operating forces are to be used at higher operating forces and speeds, the operation should be thoroughly examined to ensure that the operating margins are still intact


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(h) Where the Contractor offers a design which is generally well proved in service he must draw attention to any components which may have had to be modified recently or which may in fact be newly designed, even though he regards these as minor components. Changes will not be accepted which in any way invalidate the type test certification of the whole device in any respect.

(i) It is required that the circuit breakers, isolators, grounding switches and operating mechanism should be of the highest reliability.

(j) All rubber components of the circuit breakers should be completely suitable for their duty and should maintain their effectiveness indefinitely in the case of joints, gaskets and other such non-working parts. In the case of rubber parts subject to dynamic stresses, e.g. valve faces, they should also maintain their effectiveness indefinitely.

(k) However, where they can readily be replaced without replacing the components in which they are mounted then they should be effective for a period of at least ten years under service conditions without replacement and without detriment to circuit breaker operation.

(3) The Contractor shall state in his technical description of the GCB offered such details as are necessary to assess their offer in the light of the above design, construction and maintenance principles.

(4) A lightning arrester and a surge capacitor at each phase should be provided at 19kV line side. Technical data of lightning arrester and surge capacitor shall be quoted by Contractor.

6.5.2.9 Control Philosophy

(1) The GCB isolating switch and grounding switch controls shall operate at 220V DC

(2) Mechanically latched contactors shall be provided on all controls.

(3) Motors shall be protected by thermal overload protection.

6.5.2.10 Circuit Breaker Control Cubicle

(1) A control cubicle shall be provided for the GCB’s, isolators and grounding switches.

6.5.3 Diesel Generator

6.5.3.1 General

A Diesel generator set shall be provided for the plant, one per Unit. These generators shall be supplied complete with accessory components required for the operation of the Diesel engine includes: one fuel tank, unit control structure, lubricating oil system, cooling system, DC starting power system, and synchronizing equipments, etc.

Diesel electric generators and its auxiliaries shall be independently operated and capable of meet all emergency power requirements in the power plant.


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6.5.3.2 Type of Plant

The Diesel generator set shall be a stationary industrial type installed on foundations inside a building. The fuel oil tank, cooling system and exhaust silencer shall be suitable for outdoor installation. Both Diesel engines and generators with its exciter shall be close coupled with outboard bearing and mounted on a substantial bed plate.

6.5.3.3 Design and Selection

(1) All auxiliaries shall be selected to give matched performance.

(2) The Diesel generators shall be from an established manufacturer and the models offered shall be well proven in service with a minimum of 5 years operating experience.

(3) The design shall be such that overall functional reliability, ease of maintenance and simplified controls are given due consideration.

(4) Adequate instrumentation for control and monitoring shall be provided.

(5) All parts shall be easily accessible for operation and maintenance. Where necessary, the Contractor shall provide all necessary platforms and steps.

(6) Spare parts shall be interchangeable and satisfactory inventories shall be available.

(7) The Contractor shall describe the type and nature of after sales facilities available in Vietnam.

6.5.3.4 Rating of Plant

The Contractor shall determine the rating of each Diesel generator based on the philosophy and parameters described hereafter. The rating is expected to be about 1000kVA. These ratings are for indicative purposes only and not a mandatory constraint on the Contractor.

(1) The Diesel generator set with its auxiliaries shall be capable on it own of providing electrical power to maintain the boiler turbine unit 1 and unit 2 and associated auxiliary plants together at the power station in a safe condition following a shut-down under emergency conditions with a margin of at least 10%. A typical case is the loss of all external power supply to the station.

The loads to be supplied by the Diesel generators in an island condition shall as a minimum include the following:

AC turbine turning gear

AC turning gear oil pump (if forming part of the Contractor’s design)

AC hydrogen seal oil pump (if forming part of the Contractor’s design)

AC turbine oil tank vapor extractor

AC main oil pump

AC steam feed pump turning gear


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AC steam feed pump oil pump

AC flame scanner fan

boiler fan’s oil pumps

gas air heater lube oil pump

Diesel oil forwarding pump

gas air heater main drive

any other AC drives required for a safe shutdown

battery chargers

Diesel generator auxiliaries

plant control room lighting (via battery chargers/UPS)

switchyard control room lighting (via battery chargers/UPS)

stack obstruction lighting (via battery chargers/UPS)

remote plants emergency lighting (via battery chargers/UPS)

Human Machine Interfaces (via battery/UPS)

CCTV (via battery/UPS)

lifts

fire fighting system

control air compressor

Contractor will be required to make their own assessment of Diesel generator loads for generator capacity.

(2) For any motor being supplied from the islanded Diesel generator, the voltage drop at the motor terminals during starting shall be no greater than 15% from the pre-start voltage level.

(3) The frequency drop during the connection of any block of load to the islanded Diesel generator shall not exceed 2.5 Hz of rated.

(4) For design purposes the ambient temperature (outdoor) shall be that given in Volume 2.

(5) The Contractor shall describe the loads to be connected to the Diesel generators and submit calculation sheets to the Employer for approval.

(6) The Contractor shall guarantee the performance of the Diesel generator with acceptance tests in accordance with ISO 3046/2 and IEC 60034-1.

6.5.3.5 Operating Philosophy

The Diesel generator shall form part of the emergency power supply system whose purpose is to protect the boiler/turbine-generator plant and to maintain systems necessary for the safety of personnel in the event of loss of normal AC supplies – refer to single line diagram in Volume 9 Drawings. In the immediate


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aftermath of loss of AC supplies, plant safety shall be maintained by DC auxiliaries supplied from the 220V DC systems. The batteries will be sized to be capable of maintaining the safety of plant of the generating unit without restoration of the battery chargers for 1 hour with both station batteries available and 1/2 hour with one.

The Diesel generator shall start automatically and excite to rated generator voltage as soon as possible after loss of normal AC supply, then restoring power supplies to the 400V station emergency bus. The ICMS will initiate automatically the loading sequence to the AC safe shutdown supplies and the 220V battery chargers. Once emergency shutdown supplies are established, the Diesel generator shall maintain voltage and frequency of the island system within specified ranges while the critical AC auxiliaries are re-started to replace the DC shutdown auxiliaries until normal AC supplies are restored. Also refer to Clause 6.3.1.5 for further details.

Shutdown of the Diesel generator shall not occur automatically on restoration of normal AC supplies, but only by manual operator action.

For a description of the AC power distribution system operation, refer Clause 6.3. For a description of the DC power distribution system operation, refer Clause 6.4.

6.5.3.6 In Service Testing

Provision shall be made for testing the Diesel generator from the PCR via a single control command. The aim of the tests is as follows:

(1) Prove reliable starting. The point in the control system at which the test is initiated should ensure that as much of the automatic start logic as possible is included in the test.

(2) Prove the ability of the Diesel generator to successfully respond to step load changes up to the largest single load both in load addition and load rejection.

(3) Prove the ability of the Diesel generator to continuously supply its maximum isolated load and its rated output when connected in parallel with the normal 400V source of supply.

The Diesel generator shall have its own controller to enable periodic testing of the Diesel generator following a command to start from the PCR. Shutdown of the Diesel generator shall not occur automatically after the load tests, but only by manual operator command.

6.5.3.7 D.C. Auxiliaries for the Diesel Generators

In the event that the Contractor requires a DC supply to the Diesel generator for control purposes, for the supervisory system, or for the running of its stand-by pumps etc., prior to establishment of Diesel alternator voltage, he shall include for the provision of the appropriate battery systems complete with trickle/boost charging equipment local to the Diesel generator. See also Clause 6.5.3.6.


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6.5.3.8 Extent of Supply

This clause shall be used solely as a guide to the works involved. It in no way alters the responsibility of the Contractor as detailed elsewhere in this Specification.

The Diesel generator shall be complete with all necessary associated ancillary Plant, controls and services as follows:

(1) A starting system capable of starting the Diesel engine in any position without the need to use the barring gear.

(2) A lubricating oil system with pumps, filters, oil cooler, piping and controls not relying on AC supplies.

(3) An engine cooling system which does not depend on the operation of cooling systems elsewhere in the power station and has sufficient capacity to maintain safe operating temperatures within the specified ambient temperature range.

(4) Local and remote control facilities including a Diesel generator control cubicle and Diesel generator auxiliary switchboard, both located in the Diesel generator room, together with instrumentation protection and alarms and all necessary provisions for starting, loading, testing, control and shut down.

(5) A complete engine air intake system.

(6) A lagged exhaust system with silencers mounted on separate structure outside the building and an unlagged discharge above the level of the engine room roof.

(7) All water, and fuel services systems.

(8) A fuel oil day storage tank and complete reticulation for start-up and running purposes.

(9) Provision of all appropriate control, protection and alarm signals to the PCR.

(10) Provision of all necessary instrumentation on Diesel generator and auxiliaries, and associated cabling.

(11) Provision of all necessary fire detection devices on Diesel generator, auxiliaries, and associated cabling to PCR.

(12) All local power and control cabling.

(13) Batteries supplied with chargers and DC distribution system if applicable.

(14) Removable guards for any exposed moveable part of the Diesel generator or an auxiliary, for personnel protection.

(15) Provision for connecting / disconnecting generator neutral point to the station earth grid.


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6.5.3.9 Particulars of Plant

(1) Diesel Engine

(a) General

The Diesel engine offered shall operate on either the 2 or 4 stroke cycle and be suitable for operating with the same fuel oil used by power station mobile Plant. It shall be of proven design, with a record of successful and low maintenance performance in the size and configuration offered and with a proven record of start reliability. The maximum speed of the Diesel Plant offered shall not be more than 1,500 rpm. Units are required to be capable of rapid loading.

(b) Barring Gear

Manual barring gear only shall be provided. It shall not be necessary to operate the barring gear in order to start the generator.

(c) Engine Design

The engine shall comply with the requirements of ISO 3046 as applicable. The engine shall be designed and constructed to achieve low wear rates and low oil consumption in the cylinders, to give adequate cooling to cylinders and valves and to minimize dismantling for access to components requiring regular maintenance.

The Contractor is required to set out particulars of the design offered and, where practicable, substantiate the claims with records of actual engine performance.

It is preferred that the following design features be incorporated:

Cylinder liners manufactured wholly from a single high quality material with inherent anti-galling and oil retaining properties with the working surfaces finished in a manner to enhance these properties. Chrome plated liners will not be accepted.

Piston and ring materials are fully compatible with the abovementioned liner properties.

Inlet and exhaust valves in separate removable cages with renewable guides fitted to all valve stems.

Valve, valve seats and valve cage materials selected for operation over a whole range of engine loading. Valve seats deposited by welding on base metal will not be accepted.

A separate fuel pump to each injector is preferred but fuel pumps and injectors shall be of a well proven type and full details shall be submitted by the Contractor for approval by the Employer.

Covers over the valve gear shall be of robust construction with strong locking facilities.


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The engine crank case shall be provided with suitable safety devices to minimize the possibility of a rapid increase in pressure in the crank case above the permissible level.

The engine shall be tested in the maker's works in accordance with ISO 3046-1 and ISO 3046-2.

(d) Combustion Air

The pressure charger shall be of an approved make and type and driven by the exhaust gases. For engines of the two-bank construction there shall preferably be a pressure charger for each bank.

The air inlet of each pressure charger shall be arranged so that the ingestion of air borne dust is minimized. The inlet shall incorporate a silencer and filter. The filter shall be suitable for operation in a heavily dust laden atmosphere and shall comply with ISO 5011.

The air filters shall be readily accessible and any necessary platforms and ladders shall be provided to facilitate easy removal and washing.

(e) Exhaust System

The exhaust duct from the engine to the silencer shall pass through the side wall of the building and shall include adequate thermal expansion bellows. This ducting shall be supported such that no loads are transmitted onto the generator casing or onto the building structure.

The exhaust duct and silencer shall be either hot dipped galvanized or alternatively constructed in stainless steel of adequate thickness to withstand all structural, thermal and wind loads. Expansion bellows shall be in stainless steel. Unlagged portions of the exhaust system, if not in stainless steel, shall be painted externally with approved paint.

Silencers shall be mounted on independent structures outside the building and the exhaust piping shall be arranged to discharge above the level of the building roof. For limits on noise levels see Volume 2.

The exhaust piping up to and including the silencer shall be lagged and the section outside the building shall be sheet metal clad.

(f) Access Requirements

Adequate platforms and stairways shall be provided to facilitate inspection, maintenance and overhaul.

All such platforms and stairways shall be kept well clear of crank case doors or any other removable items.

Rung type ladders will not be acceptable.

(g) Vibrations and Noise Level

In order to reduce noise levels and vibrations within the Diesel generator building, the sets shall be mounted on resilient mountings.


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These mountings shall preferably be of the steel spring type in combination with rubber pads. The Contractor shall ensure that sufficient mountings are provided to reduce foundation loadings to an acceptable level.

The mountings shall be of the adjustable type to equalize the loading and for levelling purposes to uneven foundations.

Flexible connections shall be provided between the engine and fuel lines, exhaust system, radiator air discharge duct, combustion air inlet duct, conduit for control and power cables and any other externally connected support systems.

The Contractor shall be required to support all pipes and ducts on one or both sides of such flexible connections as necessary.

Sound levels in accordance with Volume 2.

(2) Lubricating Oil System

(a) General

The engine shall be provided with a forced lubrication system incorporating oil pump, oil coolers, filters, oil reservoir, pipework, valves, and instruments.

If the main oil pump is driven from the engine then facilities shall be provided for priming the system by a 100% duty electric motor driven pump, supplied from the emergency Diesel generator’s battery system, which will be arranged to pump for 10 minutes in every hour whilst the Diesel is shut down or at an interval considered sufficient to ensure that the Diesel engine bearings are ready for an instant start. The electric stand-by pump shall be arranged to start automatically on loss of lubricating oil pressure. A hand operated priming pump shall also be supplied and fitted for hand priming purposes.

The capacity of the lubricating system shall be adequate for the combined requirements of the Diesel engine and generator.

Where an engine driven pump is fitted, it is preferred that the pump can be readily isolated from the engine (without affecting its reliability) so that the engine may be placed in service on the stand by pump in the event of a failure of the engine-driven pump only.

Means shall be provided to collect any lubricating oil likely to leak or drip from the unit and return it by suitable drains to a collecting point for disposal.

The Contractor shall indicate in the Schedules the guaranteed lubricating oil consumption in litres per engine hour and the period of running necessary to achieve stable oil consumption conditions.

Facilities for draining the lubricating oil from the sump shall be provided. The Contractor shall include a description of how the draining and replenishment is done during the detailed design stage.


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(b) Filters

At least two lubricating oil filters shall be provided. They shall be suitable for the nominated grade of oil and be of the total flow type.

The filters shall preferably be capable of being cleaned by one man without the use of tools.

Each filter shall be fitted with a differential gauge and alarm and shall have interchange valves interlocked to prevent total isolation of the oil filtration system.

(c) Coolers

Oil coolers shall preferably be of the tube in shell type and the tube bundle shall be removable.

Facilities shall be provided to enable oil from the engine sump to be discharged into drum containers for disposal.

(d) Supply of Lubricating Oil

The Contractor shall provide all necessary lubricating oils and greases for initial running.

(3) Fuel Oil System

(a) Fuel Supply

The light fuel oil supply for power station mobile Plant is received by road tanker and this oil will be used as Diesel fuel.

Each Diesel generator day tank shall be supplied from the bulk storage tank, in an arrangement which automatically maintains enough fuel in the day tank to achieve the required running time of the Diesel generator, when it is required for emergency power supply.

A local filling branch for each day tank with valve and screw cap shall also be provided.

(b) Day Tank

The day tank shall have sufficient capacity for at least 8 hours of engine operation at full load. An alarm shall be provided which warns that the volume of fuel in the day tank is less than this amount.

The tank shall be horizontal mild steel cylindrical welded construction with plate thickness not less than 4 mm.

The tank shall be mounted on a platform at a height such as to feed the engine by gravity. All steelwork, access ladders, platforms for access and maintenance shall be provided.

The tank shall be fitted with high and low level switches and an inlet control valve to automatically maintain the level of the fuel between pre-set levels. The inlet control valve shall be mounted externally to


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the tank. A manual by-pass valve shall be provided around the inlet control valve.

A remote reading level indicator shall be mounted on the control cubicle.

The fuel tank shall be enclosed in an oil retaining bund with fire walls. The inlet and outlet isolating valves shall be located outside the fire walls in a suitable position for safe access during a fire situation.

(c) Recirculation

The Contractor shall supply all piping, isolating valves, non return valves, drains, overflows, air release valves, vents, supports, recirculation valves, piping, safety devices, alarms and initiating devices necessary for the safe and convenient operation of the Plant.

The filtering system shall include at least two (2) stages of filters capable of retaining all particles above five microns in size, and a water separator.

(d) Flow Meter

An accurate flow meter for measuring the fuel consumption of the Diesel generator shall be provided.

Indication of the fuel consumption shall be provided on the control panel.

(4) Engine Governor

(a) Governor Operation

The engine shall be provided with a suitable governor in accordance with ISO 3046/14 and as specified hereunder so as to operate steadily at any load within its rated load.

The maximum change of speed expressed as a percentage of the rated speed on sudden application or rejection of the largest load specified in Clause 6.5.3.4 shall not exceed 10%.

The recovery time for temporary disturbance within the steady load speed band at the new load shall not exceed 5 seconds after a change of load of 20% of the rated load.

Means shall be provided so that the speed of the engine may be varied gradually over a range of 5% below rated speed to 5% above rated speed, either manually at the engine or by means of a speeder motor, or equivalent, controlled from the Diesel generator control cubicle. The speeder gear shall also be controllable from the PCR.

The speed droop characteristics of the governor shall be readily adjustable both for islanded operation and for parallel operation.

(b) Emergency Governor


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A suitable independent emergency governor shall be provided to stop the engine in case of overspeed, adjustable between 10% and 15% of rated speed.

(5) Starting System

The starting system shall be capable of five attempts at starting in the absence of external sources of power.

It is expected that the Contractor will offer an electric starting system. However, if a compressed air system is offered, non-return valves shall be fitted to a sufficient number of cylinders to enable the machine to be started from any angular position without the need to bar the unit.

The Contractor shall provide a description of the starting system offered as part of his bid submission.

A compressed air starting system shall comply with the following clauses.

(a) Receivers

Each receiver shall be complete with pressure gauge, alarm contacts, relief valve, automatic moisture trap and by-pass, isolating and drain valves. Adequate provision shall be made for internal inspection.

Each air receiver shall have a storage capacity sufficient to provide the air required for at least five engine starts without recharging the receiver.

(b) Compressors

2x100% electric driven compressors should be provided, alternatively one electric driven compressor and one combustion engine driven mobile compressor of same rating. Each receiver shall be provided with one 400V AC electric motor-driven air compressor of sufficient capacity to charge the receiver in a period not greater than 30 minutes. The compressor shall be arranged to automatically maintain the required air pressure in the receiver.

All necessary interconnecting pipework in butt welded steel and automatic drain traps shall be provided.

(6) Cooling System

Cooling of the engine shall be provided by a closed loop pressurized water system(s) with pump(s) circulating the water between the engine and a fan cooled radiator.

The water shall be suitably dosed with corrosion inhibitor.

The fan(s) shall be enclosed in a substantial shroud for physical protection of personnel and for increased efficiency. If the radiator is located within the room, flexible ducting shall be provided between the radiator and the wall of the building to ensure that all heated air is directed out of the engine room.

(a) Water Heating


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The offer shall include a thermostatically controlled heater in the cooling water system to maintain the water temperature in the 25ºC to 40ºC range to facilitate easy starting of the Diesel. A water circulating pump driven by 400V electric motor and associated controls shall be included in the system.

(b) Make-Up Water Tank

A make up water tank of adequate capacity shall be provided. It shall be located at a suitable position giving sufficient head by gravity. The tank shall be complete with all fittings, inlet ball valve, and drain and overflow piping and isolating valves. Materials used shall be corrosion resistant.

(c) Alternative Cooling System

The Contractor may offer as an alternative an evaporative type cooling tower arrangement complete with fans, pumps and all integral pipework.

In this case the Contractor shall state any improvement in engine output that may be expected using this method and the amount of make-up water required.

(d) Pipework and Valves

The cooling water circulating pipework shall be in solid drawn copper.

All necessary integral pipework and valves shall be provided and all necessary precautions shall be taken to ensure that the piping will be free from vibration problems. Compression fittings will not be acceptable.

Pipework shall be installed such that it does not prevent free and easy access around the Diesel generator unit and auxiliaries.

All pipework and valves, shall comply with the requirements of the relevant portions of Volume 2.

(7) Instrumentation

The Plant shall be supplied with all necessary instrumentation for control and monitoring purposes and shall comply with the requirements of the relevant portions of Volume 2 and Volume 7.

(a) A minimum requirement for local instrumentation, as a guide, is given under Clause 6.5.3.9 (13)

(b) All instruments shall be easily accessible. The installation shall be in accordance with Volume 2.

(c) In addition to local indication, all vital instrumentation and controls shall be transmitted to and mounted on the Diesel generator control cubicle as specified under Clause 6.5.3.9 (13)

(d) All calibrations shall be in metric units.

(8) Generator


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(a) General

The generator shall be of the horizontal shaft, brushless, rotating field, solidly coupled to the Diesel engine flywheel, and shall meet the requirements of IEC 60034 and this Specification.

(b) Rating

The continuous maximum rating of each generator shall match the ISO 3046/1 rating of the engine and satisfy the requirements of Clause 6.5.3.4, 6.5.3.5 and 6.5.3.6. The generators shall be designed for the following conditions.

Rated voltage 400V

Rated frequency 50 Hz

(c) Enclosures

Generators shall be totally enclosed air circuit air cooled type to IEC 60034-6 with a degree of protection of IP56 to IEC 60529.

Exciters shall be totally enclosed fan cooled type to IEC 60034-6 of with a degree of protection of IP56 to IEC 60529.

(d) Insulation

Insulation of generators and exciters shall be rated at Class F to IEC 60034, but the limit of temperature rise shall be that nominated for Class B insulation.

(e) Stator

The stator casings shall be of fabricated steel construction, and the stator core shall be made of high permeability low loss stampings tightly clamped so as to reduce noise and vibration to a minimum.

The stator windings shall be of copper, star-connected, with all six terminals brought out. The windings shall be effectively braced and blocked to withstand, without damage or permanent deformation, the forces resulting from single or three-phase sudden short circuits at the terminals. The stator windings shall have full insulation; graded insulation is not acceptable.

(f) Rotor

The rotor shall be of the outboard pedestal bearing arrangement with over-hung exciter. Bearings shall be of the sleeve type with flood or pressure lubrication from the engine lubricating oil system, fitted with embedded thermostats for alarm purposes, and sight flow provision in the oil drain. They shall be insulated.

Pole and damper windings shall be suitably braced to prevent damage in service, and damper windings shall be adequately rated for currents due to transient and/or cyclic irregularity conditions.

(g) Temperature Detectors


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At least three embedded temperature detectors shall be provided in the generator stator winding, brought out to a common terminal box in the stator frame in a position accessible during normal operation i.e. separate from the power cable terminal box and the space heater terminals.

Temperature indication derived from these detectors shall be provided on the Diesel generator control cubicle and be relayed to the PCR. The detectors shall also be used as a basis for initiating high stator temperature alarms.

(h) Space Heaters

Space heaters shall be provided to maintain the generator internal temperature above dewpoint when the generator is at rest. Terminals for space heaters shall be separately housed from those for power cable and instrument cable termination.

(9) Exciter

The exciter shall be of the over-hung brushless type with rotating rectifier assemblies. Excitation of the exciter may be by permanent magnet generator or DC flashing. Excitation shall be possible in the absence of normal station AC supplies.

(10) Neutral Earthing

Each generator neutral point shall be connected to the station earth grid in a manner described in Volume 2.

(11) Excitation Controller

Each generator shall be provided with a solid-state excitation controller which, by controlling the field current of the brushless exciter, will provide automatic regulation of generator terminal voltage with changing load. Manual control of excitation current shall also be provided as backup to the voltage regulator and for maintenance purposes.

The excitation controller shall provide for automatic build-up to rated generator voltage as part of the starting sequence of the Diesel generator set. The sequence shall end with the automatic voltage regulator being in control, in preparation for synchronizing.

(a) Automatic Excitation Control

The voltage controller shall include at least the following features:

Load drop compensation

Under and over excitation protection

(b) Manual Excitation Control

The manual excitation controller shall follow-up the automatic voltage regulator to ensure “bumpless” transfer of control on trip of the automatic controller.

(12) Diesel Generator Auxiliary Switchboard


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Each set shall be provided with a Diesel generator auxiliary switchboard which is physically separate from the other. They shall comply with the requirements of Volume 2.

Anti-condensation heaters shall be provided in accordance with Volume 2.

(13) Diesel Generator Control Cubicle and Controls

(a) General

The Diesel generator shall be provided with a Diesel generator control cubicle to be mounted in the Diesel generator room adjacent to the set of the Diesel engine skid. The cubicle rating shall be that applicable to a switchboard in the same location - refer Volume 2. The Diesel generator control cubicles shall contain all the controls, alarms and indication, with certain functions repeated in the PCR.

Anti-condensation heaters shall be provided in accordance with Volume 2.

(b) Diesel Generator Controls

The following controls shall be provided on the Diesel generator control cubicles:

Local/remote (PCR) control selector switch (with key lock)

Test start Diesel generator: initiation of automatic start and run-up sequence and excite the generator to rated voltage as per Clause 6.5.3.6

Run Diesel engine only: start engine and run-up to rated speed

Excite generator: establish generator rated voltage ready for manual synchronizing

Normal stop

Emergency stop, which shall also trip the Diesel generator circuit breaker and excitation

A.V.R. voltage raise/lower

Governor speed raise/lower

A.V.R. auto/manual selector switch

Excitation manual raise/lower

Generator circuit breaker open/close

Synchroscope on/off (also provides an interlock to enable closure of generator circuit breaker)

Anti-condensation heaters on/off

Jacket water heaters on/off

(c) Diesel Generator Indication - Control Cubicle

The Diesel generator control cubicles shall include the following minimum indication:

Generator power output (kW)


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Generator reactive power output (kVAR, centre zero meters)

Generator frequency (Hz)

Generator voltage (V)

400V station switchboard voltage

Generator current (in A for each phase)

Synchroscope

Generator kWh - Meter

Hours run meter

Exciter field voltage (V)

Exciter field current (A)

Generator bearing temperatures

Generator winding temperatures

Shaft speed (rpm)

Day fuel oil tank level

Fuel consumption indicator

Lube oil pressure

Lube oil temperature

Jacket water temperature

Engine exhaust temperature

Intake air cooler temperature

Air receiver pressure

Battery charge current (A)

(d) Diesel Engine Indication - Local to Engine

In addition to the above the Contractor shall provide to the Employer for approval the details of locations and number of instruments he will be providing for local indication. Such gauges shall be of sufficient number for monitoring the status of the Plant and shall include the following:

Cooling water inlet and outlet pressure and temperature

Lubricating oil inlet and outlet pressure and temperature

Differential pressure across lube oil and fuel oil filter

Compressed air pressure

Jacket water outlet temperature of each cylinder

Intake and exhaust gas temperature


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Bearing temperature.

(e) Plant Status Indication and Alarm Annunciation

The philosophy and style of display of Plant status and the annunciation of alarms associated with the Diesel generators shall be consistent with that applied to Plant controlled from the PCR so as to avoid confusion on the part of the operators as to what a particular display indicates.

The status of any Plant which may be unavailable for automatic start of the Diesel generator shall be indicated on the Diesel generator control cubicle to provide the operator with sufficient information to assess the overall status of the Plant without having to inspect equipment individually. Unavailability for automatic start or remote control shall be indicated in the plant control room.

Each Diesel generator shall have its own annunciator system mounted in the Diesel generator control cubicle, and incorporating “first-up fault” indication. It may be part of the sequence control system. All necessary equipment shall be included to enable repetition of a “general alarm” in the PCR. Allowance to enable up to 20% additional alarms to be added shall be provided.

An audible alarm shall be provided in each Diesel generator control room, to be operative only when the Diesel generator is under local control.

The operation of any Diesel generator protective device shall be individually alarmed.

(f) Plant Control Room

The Contractor shall provide feedbacks to the PCR of all the status conditions of the Diesel generator system to allow operator to monitor remotely all conditions of the Diesel generator from the PCR.

The following list is included as a guide. The Contractor shall state in his offer what facilities he recommends to provide for safe, reliable, automatic and manual starting and operation.

Control

Manual start Diesel generator: operator shall be able to start the Diesel generator by making a single “start” command remotely from the PCR. Once receiving the remote start command, the Diesel generator shall automatically start up and run-up the loading sequence to restore power for emergency drives.

Stop Diesel generator. After a successful start, the Diesel generator can only be stopped when receiving “stop” command from the operator, either via the local control panel or remotely from the PCR.

Periodic test Diesel generator: operator shall be able to initiate the testing of the Diesel generator by making a single “test” command remotely from the PCR. Once receiving the remote “test” command, the Diesel generator shall automatically start up and run-up the “test” sequence to its full capacity. After a successful test, the Diesel generator can only be stopped when receiving


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“stop” command from the operator, either via the local control panel or remotely from the PCR. See Clause 6.5.3.6 for further details of test runs.

Indication

Generator power output (kW)

Generator reactive power output (kVAR, centre zero)

Generator frequency (Hz)

Generator voltage (V)

Station 400V switchboard busbar voltage (V)

Generator current (A)

Diesel engine speed (rpm)

Lubricating oil pressure (kPa)

Jacket water temperature (ºC)

Battery voltages

Status

Diesel ready to load

Limit of excitation adjustment reached

Limit of governor speed adjustment reached

Diesel generator unavailable (conditions monitored to be listed)

Generator reactive power limiter operating

Excitation high

Local / remote indications

Alarms

Diesel generator general alarm

Lubricating oil pressure low

Lubricating oil temperature high

Jacket water temperature high

Diesel failed to start/shut-down

Diesel generator overload

Battery failed.

Control Circuit Supply Supervision

Control supplies shall be monitored and raised undervoltage alarms if they are absent.

(14) Generator Protection


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Generator protection shall generally comply with the requirements of “Electrical Protection” included in this Specification. The Contractor shall provide at least the following generator protections:

Differential

Back-up overcurrent

Back-up earth fault

Reverse power

Thermal overload

All protections listed above shall trip the 400V circuit breaker, generator excitation and the Diesel engine and raise an alarm, except for thermal overload which shall alarm only.

The Contractor shall describe the proposed generator protections to the Employer for approval.

Test links shall be provided in current and voltage input circuits to electrical protection relays. Trip isolation links or other means of providing isolation of in-service protection relays for test shall be provided.

(15) Batteries

(a) If batteries are required (see Clause 6.4), they shall be of the valve regulated lead acid (VRLA) batteries complying with IEC60896-21 and IEC 60896-22 and shall be provided with 100% rated duty float/boost chargers. The batteries shall be sized to supply at least five black starts and in addition one black shut-down without the need for recharging. Under normal operation the chargers shall supply the required DC load and at the same time automatically float charge the battery to keep it fully charged within the correct voltage limits.

(b) Selection of boost charge shall be manual, and controlled by a preset timing switch. The boost charge shall be such that the time for recharging the battery from the discharged condition to 90% of the fully charged condition, and at the same time supplying the DC load requirements, does not exceed eight hours.

(c) Chargers shall be of the natural cooled type.

(d) Batteries and charger should not be installed in the Diesel engine room but in a dedicated battery room close to the engine complying with standard IEC 60079.

(16) Fire Protection and Detection

Fire protection for the Diesel generator and associated Plant shall comply with the requirements of Volume 4 and the relevant NFPA Code.

The Contractor shall provide fire detection devices for the Diesel generator and associated Plant and alarm status feedbacks to the PCR.

(17) Painting and Finishing


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Painting and finishing for the Diesel generator and associated Plant shall comply with the requirements of this Specification.

(18) Platforms, Walkways, Stairs and Ladders

The Contractor shall provide all necessary platforms, galleries and stairways required for access to all parts of the Plant requiring inspection and maintenance. Such access facilities shall include the tops of all engine cylinders, engine controls and instruments, fuel tank, make-up water tank and cooling tower fan (if any).

(19) Piping

Piping shall comply with the Specification and shall be of butt welded construction. Flanged joints shall be used only for connection to equipment, valves and fittings. Screwed joints and compression type joints shall not be used for fuel, lubricating oil and compressed air supply. Copper piping shall not be used for fuel or lubricating oil services.

Piping shall be neatly arranged and adequately supported. The Contractor shall submit detailed arrangement drawings of all pipework for approval by the Employer before erection at Site.

(20) Valves

Valves shall conform to the Specification.

Valves shall have flanged end connection. Screwed valves shall not be used unless specifically approved. Valves for air, water, fuel and lubricating oil services shall be globe or gate type.

All valves shall be provided with a valve number and nameplate inscription approved by the Employer. IEC 81346 RDS-PP (Reference Designation System – Power Plants) shall be used.


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6.6 HIGH VOLTAGE SWITCHYARD

(Refer to Appendices 3 & 4 for further specific requirement and arrangement details. The appendices take precedence over this sections content.)

6.6.1 General

6.6.1.1 Scope of Works

The Works for the power station high voltage switchyard covers the design, manufacture, delivery, installation, construction, testing and commissioning. The scope of the works for the switchyard shall include but not be limited to the following:

(1) Design and construction of electrical works.

(2) Design, manufacture, testing, delivery and installation of switchgear, protection and communication systems and all Plant and materials.

(3) High voltage busbars and connections.

(4) All AC and DC power systems.

(5) All power and control cabling.

(6) Interfaces to the power station for control, protection, communications, power supplies, earthing, etc.

(7) Any Plant, materials or services required for the satisfactory completion and placing into operation of the works.

Detailed Scope of Works for the power station high voltage switchyard as follows:

(1) The diagram of 220kV side is designed as a 1 ½ breaker with 3 circuit breakers for 2 outgoing feeders. This design ensures high reliability and the combined control-protection equipment works simply and reliably. 220kV side is composed of:

2 feeders for main transformers (GT1, GT2)

2 feeders for 220kV transmission lines to Thai Binh Substation

01 feeder for 220/6.6-6.6kV-44MVA Station Transformer

Number of spare bays: 9 bays (connection with Thai Binh 2 TPP).

The switchyard layout Drawing included in Volume 9 provides a physical arrangement of the initial development and space for the ultimate development for the switchyard.

The Contractor is at liberty to offer alternative designs for the layout of the switchyard which meet the requirements of this Specification. Preliminary layouts and single line diagrams shall be submitted as part of the bid.


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Please refer to Plant overall single line diagram in Volume 9 Drawings for scope of work.

Contractor shall submit the names of manufacturers and types and models of equipment offered. Technical data, descriptive information, drawings and brochures showing all significant characteristics and details, principle of operation, general arrangement and dimensions shall also be included for determination of the suitability of the equipment for its purpose.

6.6.1.2 Design Parameters

(a) Nominal system voltage kV 220

(b) Highest system voltage kV 245

(c) Rated voltage kV 220

(c) Lightning impulse voltage (pk) kV 1050

(d) Frequency Hz 50

(e) Power frequency (rms) kV 460

(f) Minimum creepage distance mm/kV 31

(g) Rated short circuit current (sym) kA 50/3s

(h) Protection standard

- for indoor equipment IP-44

- for outdoor equipment IP-56

(i) Auxiliary electric source

- AC 400/230V

- DC (use for control-protection) 220V

- Pollution level Heavy

- Tropicalisation Required on all equipment

- Ambient conditions Refer to Volume 2

- Standards Vietnamese and International

6.6.1.2.1 Switchyard Equipment Ratings

Circuit Breaker

- Standard: IEC 62271-100

- Rated voltage: 245kV

- Type: SF6, outdoor 1 pole per phase, outdoor location (3 phase)

- Rated current: 3150A

- Short-circuit current: 50kA/3s

- Operating mechanism type: spring charged or hydraulic (motor/ manual)

Disconnector


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- Operating mechanism type:

- motorized for disconnector switch

- manually operated mechanism for earthing-blade

+ electrical and mechanical interlocking device

- Type: three-phase, outdoor, centre break

- Rated voltage: 245kV

- Type: 3 phase

- Rated current: 1600A

- Short-circuit current: 50kA/1s

Capacitor Voltage Transformer for protection

- Standard: IEC-60044-5

- Type: outdoor, single phase

- Rated voltage: 245 kV

- Ratio: kV3

11,0/

3

11,0/

3

11,0/

3

11,0/

3

220

(main metering points)

kV3

11,0/

3

11,0/

3

11,0/

3

220

(standby metering points)

- Capacity: 4400 -:- 6400pF

- No. of secondary windings: 2

- Accuracy: 0.2, 0.5 and 3P

- Burden: 50 VA

Current Transformer

- Standard: IEC-60044-1

- Type: outdoor, single phase, oil-immersed


- Ratio: 600-800-1200-2000/1A

- Number of secondary winding: 6

+ Core for protection class 5P20 (core 3,4,5 & 6) 30VA

+ Core for measuring standby No.1 & No.2 class 0.5 (core 1,2) 30VA

+ Core for measuring at main tariff points class 0.2 (core 2) 30VA

Surge Arrestor


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- Type: outdoor, ZnO, single phase

- Maximum voltage: 245 kV


- Maximum continuous working voltage: 154 kV

- Residual voltage with lightning impulse (8/20s): 505 kV

- Capability of energy absorption: 7.8 kJ/kV(Ur)

- Includes lightning counter.

6.6.1.2.2 Reclosing Equipment

The 220 kV line switchbays shall be equipped for slow speed three-pole automatic reclosure and fitted with standard blocking equipment

6.6.1.2.3 Synchronizing Facilities

The 220 kV line switchbays shall be equipped with synchronizing check facilities.

6.6.1.3 Insulation Co-ordination

6.6.1.3.1 Electrical Equipment

The co-ordination of insulation of electrical equipment and the application of protective devices to safeguard the equipment shall conform to the requirements and recommendations of IEC 60071. Insulation levels shall be as specified in Clause 6.6.1.2.

If required, coordinating rod gaps shall be fitted to the line side of line disconnectors and the bus side of one bus disconnector on each bus.

Surge arrestors shall be located at a distance of not more than twenty (20) meters from the 220 kV terminals of the generator and station transformers.

The pollution performance of all insulators and bushings shall comply with the heavy pollution level of IEC 60815.

All switchyard Plant and high voltage conductors shall be protected against direct lightning strikes by means of lightning rods on strain structure columns, separate lightning protection masts or overhead earth wires. For design purposes, the protection shall be based on a charged strike sphere of 24 m radius from all directions.

Columns, masts and earth wires shall be connected to the earth grid. Overhead earth wires shall be galvanized steel cored conductor, 7/3.75 SC/GZ.

6.6.1.3.2 Access for Operation and Maintenance

The following minimum ground safety clearance, section safety clearance and work safety clearances shall be provided in the designs to allow access at ground level and at all operating positions for operation and inspection in the vicinity of


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exposed high voltage conductors and equipment, without the need for the apparatus to be taken out of service.

Ground safety clearance is the clearance from the ground to the base of bushings and insulators which are part of equipment or those carrying high voltage conductors.

Section safety clearance is the clearance from the ground or foot position of a working platform vertically to the nearest live conductor whether on the same circuit or on an adjacent circuit or from the foot position over guard rails or screens by taut string measurement to the nearest live conductor. It is a distance which is the sum of the ground safety clearance plus the phase to earth non-flashover distance clearance.

Horizontal work safety clearance is the clearance where work is carried out from a ladder or from the equipment, from the extremities of the work object horizontally to the nearest live parts.

Vertical work safety clearance is the clearance where work is carried out from a ladder, from the highest part of the work object vertically to the nearest live parts.

Such clearances shall also allow maintenance work to be carried out at ground level or operating positions.

Ground Safety Clearances for Operation Purposes and Maintenance Work as following below (Table 6.6.1: Ground Safety Clearances);

Table 6.6.1 Ground Safety Clearances

Voltage

Minimum

Phase to Earth

Clearance

Non-

flashover

distance

Ground

Safety

Clearance

Ground Safety Clearances for Operation Purposes and Maintenance

Work

Section Safety

Clearance

Horizontal

Work Safety

Clearance

Vertical

Work Safety

Clearance

220 kV 2100 mm 2010 mm 2440 mm 4450 mm 3910 mm 3350 mm

Where the maintenance requires the use of a crane with slings and davits (for example for circuit breakers), clearance distances shall be provided from the ground to the live overhead conductors at maximum sag to allow for the sum of the above section safety clearance, the sling height, the height required to clear the largest component part of the equipment which may require removal from the body of the equipment (for example circuit breaker interrupters), other heights determined by the type of the crane which may be used and a further distance to


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provide an appropriate safety margin. This clearance shall also provide for the erection of equipment in future switchbays under existing live busbars.

Where live overhead conductors pass over access roads, clearance distances shall be allowed from the road surface to the conductors at maximum sag to provide the vertical work safety clearance on top of the highest vehicle which could use the road.

The design of the switchyard shall provide for road access to all major items of equipment and safety clearances to allow maintenance vehicles to utilize these roads without the need for circuit outages.

All clearances determined as above shall be to the approval of the Employer.

6.6.1.4 Training

The Contractor shall provide training for the Employer personnel generally in accordance with Volume 1 and this shall cover the design, manufacture, operation and maintenance of switchyard, switchyard equipment and systems, testing and commissioning.

In addition to that covered in Volume 1, the following training shall be provided for systems specific to the switchyard.

Protection Equipment

Training shall cover the design, operation and maintenance of all protection equipment including:

Each protection scheme, including settings.

Remote interrogation.

Analysis and fault location.

Microprocessors relay software and hardware.

6.6.2 Switchgear

6.6.2.1 General

6.6.2.1.1 Scope of Work

The Contractor shall design, manufacture, test and erect all high voltage equipment.

The equipment shall be manufactured and tested in accordance with the appropriate parts of IEC 62271. If the requirements of this specification conflict with any standard, this Specification shall be applied.

Erection shall be in accordance with the manufacturer’s instructions.

6.6.2.1.2 Equipment Ratings

Ratings and design parameters for all equipment shall be in accordance with Clause 6.6.1.2 and any specific requirements stated in the individual Clauses.


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6.6.2.1.3 Name Plates

Each item of equipment shall be provided with a name plate in accordance with the standard appropriate for that equipment.

The name plates shall be made of a durable, corrosion resistant material, engraved or stamped to provide permanent marking.

6.6.2.1.4 Terminal Palms

The main terminals shall be in accordance with the relevant standards unless otherwise stated in this Specification. The non-mating face shall be spot faced or medium machined for correct seating of the bolt heads and nuts.

The terminals shall be capable of withstanding the forces arising from system faults acting concurrently with the maximum wind loading.

6.6.2.1.5 Low Voltage Cable Terminations

The terminals for external connections may be of the stud type, using studs of at least 5mm diameter, or of the rail mounted insertion type. Pinch screw terminals where the screw bears directly on to the conductor shall not be used. Terminals shall have a positive locking feature provided by spring washers etc.

Wire terminations to stud type terminals shall be by means of solderless compression type lugs or another type approved by the Employer. Any links shall be of copper, studs, nuts and flat washers shall be of brass, and spring washers of stainless steel. All links, studs, nuts and flat washers shall be chromium plated.

6.6.2.1.6 Terminal Board

Each item of Plant shall be provided with a terminal board to which all auxiliary power and control supplies and all control, indication, trip and alarm circuits and instrument transformer secondary circuits which are required to leave the Plant shall be connected.

The terminal board shall be housed in a weatherproof metal enclosure or control cubicle, as specified in Clause 6.6.2.1.14.

6.6.2.1.7 Earthing Terminal

Provision shall be made for the attachment of a flat copper earthing strip near the base of the equipment and to control cubicles. Holes for bolts to attach the strip may be drilled in channel or angle members of the equipment or provided in a lug at least 10 mm thick welded to the equipment. Tapped holes and studs are not acceptable.

6.6.2.1.8 Surface Finish

All external ferrous surfaces shall be hot dip galvanized. If galvanizing is not practical, alternative surface finishes may be used, subject to approval by the Employer.


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6.6.2.1.9 Insulating Medium

The insulating fluid shall comply with the requirements of the appropriate IEC 60296.

PCB shall not be used. The insulating oil or other fluid used in the equipment shall contain no PCB.

6.6.2.1.10 Porcelain

All bushings, porcelain shells and insulators shall be of the same Colour, to the approval of the Employer.

6.6.2.1.11 Pollution Performance

The pollution level for the equipment, with regard to creepage distance and profile, shall be not less than heavy as specified in IEC 60815 - Guide for the selection of insulators in respect to polluted conditions.

6.6.2.1.12 Insulators

All insulators of each voltage shall be of the same type and shall be interchangeable between items of Plant of the same voltage.

6.6.2.1.13 Fittings and Accessories

The equipment shall be fitted with the following accessories:

(1) Inlet and outlet valves for oil sampling and filling of all oil filled equipment. Only gate type valves shall be supplied.

(2) Oil level indicator.

(3) Level indicator for any diaphragm or bellows.

(4) Pressure relief device.

(5) Lifting lugs or similar provision.

6.6.2.1.14 Control Cubicles

Control cubicles shall have doors with internal hinges and provision for padlocks. The doors of each cubicle shall be provided with stays to prevent them from swinging free. All equipment in the cubicles shall be accessible and where applicable, internal panels shall be hinged to allow access to the back of panel wiring. All joints and external attachments shall be fully seal welded.

Each cubicle shall be weatherproof with degree of protection complying with IEC 60529 designation IP55. Each cubicle shall be provided with a heater of adequate rating to prevent condensation within the cubicle under the specified service conditions. Each heater circuit shall be fused. Heaters shall be controlled in each cubicle by a humidistat with adjustable operating range and a cut-out thermostat with adjustable operating range, to prevent overheating.

A weatherproof, outdoor, 10A, single phase, 230V general purpose combination switch-plug outlet shall be fitted on the outside of each cubicle. It shall be wired to a fuse and shall be rain-protected by a canopy.


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6.6.2.1.15 Inspection and Testing

(1) General

The cost of all routine and acceptance tests and specified type tests shall be supplied as part of the bid.

Where type tests have been previously carried out for the same design of equipment being offered, these shall be listed in the schedules and copies of test certificates included.

Where such tests are for equipment not exactly as that specified, then Contractor shall provide additional information in support of the relevance of such certificates to the equipment specified. A technical assessment will be made of the information provided and where the information is considered inconclusive and further tests are required, they shall be performed at the Contractor's expense.

Where the standard provides for alternative rated dielectric test levels, the higher test level shall apply.

(2) Tests on Insulating Oil

The Contractor shall take oil samples from all equipment and perform electrical and chemical tests listed below in the following manner:

(a) One sample per processing batch prior to HV testing.

Electrical - electric strength 65 kV (min) and dielectric dissipation factor at 90ºC.

Dissolved gases - hydrogen, oxygen, nitrogen, carbon monoxide, carbon dioxide, methane, ethane, ethylene and acetylene.

(b) On completion of HV testing, oil samples shall be taken from all units of each batch and tested.

Dissolved gases - hydrogen, oxygen, nitrogen, carbon monoxide, Carbon Dioxide, Methane, Ethane, Ethylene and Acetylene

(c) Samples shall also be tested for water content, in (b), only.

(3) Check Tests by the Employer

the Employer reserves the right to direct the Contractor to carry out additional check tests. Such tests may include repetition of tests carried out at the maker's works (modified in intensity and value where provided in the relevant standards) and other such tests as may be considered necessary by the Employer to prove compliance with this Specification. The costs of these tests shall be borne by the Contractor.

the Employer shall have the right during the General Warranty Period to carry out such field tests on the equipment whilst in operation on its system as is deemed necessary.

In the event of these check and/or field tests proving that the Plant is satisfactory, all costs will be borne by the Employer, but in the case of faulty Plant, the


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Contractor shall bear the cost of the tests, of replacing or amending the Plant and all further tests in connection therewith.

Any expense in having Contractor’s representatives present at the tests shall be borne by the Contractor.

6.6.2.2 Circuit Breakers

6.6.2.2.1 General Requirements

The Circuit Breakers shall comply with IEC 62271-100, IEC 62271-1 and other relevant international standards

6.6.2.2.2 Operation Mechanism

Circuit breakers shall be motor wound spring or hydraulically operated. Motors shall be 400/230 VAC. Pneumatic operation is not acceptable.

220kV circuit breakers shall have independent pole operation to minimize the possibility of a ‘stuck’ breaker prolonging the duration of a multi-phase fault. They shall be capable of single pole, one shot, automatic, slow speed reclosing.

6.6.2.2.3 Accessories

The following accessories shall be provided with each operating mechanism:

(1) Mechanical position indicator visible externally to the mechanism enclosure marked "I" (red background) - closed; "O" (green background) - open.

(2) Duplicate trip coils for each pole which shall be mechanically, electrically and magnetically separate.

(3) One "CLOSE" push button, for each three phase breaker.

(4) Separate “TRIP” push buttons for energizing either trip circuit locally.

(5) Trip operation counter.

(6) Anti pumping relay

(7) SF6 gas density monitor shall be provided for alarm and lockout when the gas density is below the normal operating density range.

(8) Eight spare auxiliary contacts capable of being set N/O or N/C.

(9) Indicators in the form of relay flags or LEDs for monitoring alarms which shall be capable of being reset locally.

(10) Device for manual slow closing and opening of the circuit breaker during maintenance. Provision shall be made for prevention of a spring - charging motor turning the manual - charging handle if inadvertently energized during the manual charging operation. The manual operating device shall be located inside the operating mechanism box.

(11) Lifting lugs.


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6.6.2.2.4 Insulating Medium

SF6 gas is the preferred medium for arc extinction and the circuit breaker shall be supplied filled with gas complying with IEC 60376.

6.6.2.2.5 Characteristic of Equipment

The required rating for all circuit breakers shall be as follows:

(1) 220kV Circuit Breaker

(a) Standard IEC 62271-100

(b) 1 pole per phase, SF6 type and outdoor location (3 phase)

(c) Rated voltage 245kV

(d) Rated current 3150A

(e) Rated breaking current 50 kA

(f) Short circuit withstanding current 50 kA/3s

(g) Number of pole chamber 1

(h) Operation cycle O-0.3s-CO-3minutes-CO

(i) Total breaking time 70ms

(j) Total closing time 100ms

(k) Number of rated short circuit current breakings

20 times

(l) Auxiliary contacts 12NO+12NC

(m) Spring gear set ( motor / manual)

(n) Instantaneous & time O/C protection for circuit breaker

(o) Auxiliary electric source

1) motor 400/230V AC

2) Closing and tripping coil 220V DC

(p) Attached equipment support

(q) Attached equipment pole clamping



The CTs shall comply with IEC 60044-1 and all other relevant IEC standards.

The single line diagram included in Volume 9 Drawings shows the location and number of cores for CTs. However, it is the Contractor’s responsibility to design, supply and locate CTs to meet the requirements of his designs for control, protection and metering provided under the Contract.


111

6.6.2.3.2 Ratings

The rated or assigned values of CTs being offered by the Contractor shall be stated in Schedule Vol. 12 Information shall also be provided of the short time overload capabilities during periods of continuous operation at normal rated current.

6.6.2.3.3 Secondary Terminals and Terminal Box

Each end and each tapping of each secondary winding shall be brought out to a terminal board in a weatherproof and dustproof terminal box and shall be labeled in accordance with the standard. Suitable earthing terminals shall be provided in the box for earthing any unused windings.

6.6.2.3.4 Ratios

Change of ratio shall be by means of secondary tappings and not by primary reconnections. Intermediate ratios on metering "M" type CTs shall be possible by selection of any of the secondary terminals and the class must be maintained for all such ratios.

All secondary windings shall be of the multi-ratio type and have secondary tappings suitable for the initial loads and the future development of the substation and power system.

6.6.2.3.5 Secondary Windings

The windings shall be evenly distributed around the core to produce a negligible leakage reactance on all ratios.

Secondary windings and connected equipment shall be protected against damage by electrical contact with windings at system voltage as the result of breakdown of insulation, by the provision of an earthed shield between primary and secondary windings. This shield shall be earthed at the end closest to the "P2" primary terminal.

6.6.2.3.6 Current Transformer Monitoring Facilities

Monitoring facilities shall be provided for each unit and shall include:

(1) Oil level indicator and pressure indicator.

Any indicator shall have Coloured safe/danger zones and be easily visible from ground level.

6.6.2.3.7 Arc Gaps

Arc gaps shall be provided between secondary terminal S1 and the terminal of the highest turns ratio on all secondary cores where the induced open-circuit voltage between these terminals (across the full secondary winding) can equal or exceed 5kV peak with rated sinusoidal current flowing in the primary winding.

6.6.2.3.8 Partial Discharge Test

The CT shall have a partial discharge free service performance. The Contractor shall provide a table of guaranteed partial discharge magnitudes and routine test voltages for the purpose of evaluating performance.


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6.6.2.3.9 Magnetization Curve (Protection Cores)

The exciting current in the secondary winding of each core shall be measured at a number of voltages such that the saturation curve can be drawn for each core from approximately 1% to 200% of rated secondary current.

The Contractor shall present the test results obtained as a series of magnetization curves, with complete scale multiplying factors for each ratio on tapped secondary windings. Each curve shall be clearly labeled with the current transformer serial number, core number and ratio.

6.6.2.3.10 Dielectric Dissipation Factor

The dielectric dissipation factor of the high voltage insulation shall be measured as a routine test in accordance with IEC 60044-1.

6.6.2.3.11 Characteristic of Current Transformer

(1) 220kV current transformer:

Standard IEC 60044-1

Type Rated voltage

outdoor, one pole

245kV

Transformation ratios 400-800-1200/1A

800-1200-2000/1A (Feeders)

Accurate level of coil No.1, 2 0.2, 0.5 - 30VA (for measurement)

Accurate level of coils No.3, 4, 5, 6

Terminal connector

5P20 - 30VA (for protection)

6.6.2.4 Voltage Transformers


The VTs shall be of the capacitor divider type and shall be manufactured and tested in accordance with IEC 60044-5 unless otherwise stated in this Specification.

The single line diagram included in Volume 9 Drawings shows the location, voltage ratios and capacitance of VTs. However, it is the Contractor’s responsibility to design, supply and locate VTs to meet the requirements of his designs for control, protection, and metering provided under the Contract.

The rated or assigned values of VTs being offered by the Contractor shall be stated in his bid.

6.6.2.4.2 Characteristics of Voltage transformer:

(1) 220kV Voltage Transformer:



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Type of single phase, coupling capacitor and VT, outdoor.

Rated voltage 245 kV

Transformation ratio kV

3

11,0/

3

11,0/

3

11,0/

3

11,0/

3

220

Number of secondary coils 4 Main Metering points

Transformation ratio kV

3

11,0/

3

11,0/

3

11,0/

3

220

Number of secondary coils 3 Standby Metering points

Rated capacity 50VA

Attached equipment pole clamping

6.6.2.5 Disconnectors and Earth Switches


Disconnectors and earth switches shall comply with IEC 62271-102.

6.6.2.5.2 Operating Mechanisms

Disconnectors shall be power operated by means of 220V DC motors. Motors shall be protected with thermal overload devices and all “open” and “close” contactors shall be fitted with mechanical and electrical interlocking.

Earthing switches shall be manually operated and shall be designed to be mounted on either or both ends of the disconnectors.

The power operated disconnectors shall be capable of being operated manually.

The handle or operating mechanism shall be provided for the manual operation of disconnectors and earthing switches and this shall be positioned so that it allows convenient operation by one man. The maximum length of the earthing switch bar type handle shall be 1200 mm and the maximum operating force shall be 250N. The maximum operating force for the general type handle for disconnectors shall be 90N.

The earthing switch shall be designed such that if closed onto live conductors, there will be no backlash force imposed on the operator.

All disconnectors and earthing switches shall be capable of being padlocked in the open or closed position.

6.6.2.5.3 Accessories

The following accessories shall be provided, when applicable, for each operating mechanism:

(1) With power operated mechanisms - a control switch for local operation, marked “open-normal-closed”. This switch shall be spring return to the “normal” position.


114

The selector and control switches shall be mounted inside the control box.

(2) A mechanical “open-closed” position indicator. This shall accurately show the open and closed positions to reduce the possibility of causing strain to the operating gear when operating manually.

(3) Four spare auxiliary contacts capable of being set to N/O or N/C.

(4) If required by the design of the switchyard insulation co-ordination, rod gaps shall be fitted to all three phases, mounted on the required side of the disconnector.

6.6.2.5.4 Main Contacts

All contacts fixed or moving shall be made of copper for the base material with silver for the contact face material. The thickness of contact face material shall meet all service and design requirements.

6.6.2.5.5 Earthing

Each operating handle and down rod or drive shaft, shall be provided with:

(1) A flexible earth connection of not less than 70 mm equivalent copper cross sectional area

or

(2) A suitably tensioned non-ferrous wiping contact connected to an earthing terminal in the case of multi-turn handles or shafts. The earthing arrangement of the operating handle shall be separate from all others.

6.6.2.5.6 Characteristics of Disconnector

(1) 220kV disconnector:


Outdoor type 3 phase, centre break

Rated voltage 245kV

Rated current

Rated short-time withstand current

1600A

50kA/1s

Driven

- The main blade is controlled by motor - motor voltage: 220V D.C

- Earthing blade controlled manually or by motor.

With interlocked earthing blade and main blade.

Auxiliary contacts

- 6NO+6NC for the main blade

- 6NO+6NC for earthing blade

Attached equipment support

Attached equipment pole clamping


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6.6.2.6 Insulators


The insulators shall comply with IEC 60815 unless otherwise stated in this Specification.

6.6.2.6.2 Cementing of the Components of an Insulator Unit

The metal fittings and the porcelain components of an insulator unit shall be cemented together, preferably with Portland cement or alternative approved by the Employer. Sulphur cement shall not be used for outdoor insulators to cement the porcelain to the metal fitting in contact with current carrying components. A description of the method of cementing shall be supplied.

6.6.2.6.3 Test Requirements

All type, batch and routine tests for the insulators shall be carried out in accordance with the relevant IEC Standards.

6.6.2.6.4 Characteristics of Insulator

(1) 220kV supporting insulator

Standard IEC 60273 & IEC 60168

Creepage distance 31mm/kV

Minimum damaged strength

- Bending strength > 6000 N

- Tension strength > 80000 N

- Twisting strength > 5000 N

Withstand voltage

- Power frequency in dry/wet conditions 530 kV/460 kV

- Lightning impulse 1050 kV

(2) 220kV string insulator

Creepage distance 31mm/kV

Mechanic-electrical damaged strength 2 x160kN

1 x160kN

6.6.2.7 Surge Arresters

6.6.2.7.1 Standards

The Plant shall be in accordance with IEC 60099 and other relevant IEC standards.


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6.6.2.7.2 Type

The surge arresters shall be outdoor, metal oxide resistor type.

6.6.2.7.3 Sealing and Filling

The arrester shall be effectively and hermetically sealed.

The method of sealing against atmosphere shall be of a well proven type and shall be direct and positive.

Sealing surfaces shall be treated to prevent corrosion and moisture accumulation.

6.6.2.7.4 Pressure Venting

A pressure relief device shall be incorporated where there is a risk of explosive shattering of the insulator should the surge arrester malfunction. The design of the device shall be such that it may be visually determined from ground level if the device has operated.

6.6.2.7.5 Characteristics of Surge arrester

(1) 220kV surge arrester (nominal voltage)

Standard IEC 60099-4, IEC 60099-1

Type of out-door, ZnO 1 phase

Rated voltage 192 kV

Maximum working voltage 154 kV

Neutral earthing conditions effective grounded

Residual voltage (8/20s - 10kA) 505 kV

Energy absorbent ability 7.8 kJ/kV Ur

Accessories counter and insulated base terminal connectors

(2) 19kV surge arrester:



Rated voltage 15.7 kV

Maximum working voltage 12.5 kV

Neutral earthing conditions insulator grounded


Energy absorbent ability 3.6 kJ/kV Ur

Accessories counter and insulated base terminal connectors

(3) 6.6kV surge arrester


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Rated Voltage 8.4kV

Neutral earthing conditions insulator grounded

Maximum working voltage 9 kV


Energy absorbent ability 3.6 kJ/kV Ur Accessories counter and insulated base

terminal connectors

6.6.2.8 Tariff Metering

(1) General

The Contractor should refer to the Regulation of Ministry of Industry and Trade (MOIT) on Technical Requirement of Metering System for Power Station in the Circular of MOIT No. 12/1010/TT-BCT dated April 15, 2010 for the detail requirements of tariff metering design for the power plant.

Active power and reactive power of revenue metering system operate for trading purpose. The metering equipments are placed on cubicles at switchyard control room. This system is included main and spare meter.

Main meter is placed on high voltage terminals of generator transformers and station transformer.

Backup meter is placed at the 220kV outgoing feeder of Plant.

6.6.2.9 Conductors and Busbars

The 220kV system uses AAC-910, ACSR-500 conductor for connection.

a) 220kV busbar uses 2 x ACC-910 conductors.

b) Connection of 220kV equipment uses 1xACSR-500 conductor for feeders. GT1, GT2 main transformer feeders uses 2xACSR-500 conductor.

c) These conductors are fixed by clamps spaced 4m to 5m..

6.6.3 Technical Service

6.6.3.1 Protection Systems

The scope of the Work covered by this Specification includes the design, supply, installation and commissioning of protections for the following:

1. 02 feeders for main transformers (GT1, GT2)

2. 02 feeders for 220kV transmission lines:

3. 01 feeder for 220/6.6-6.6kV ST transformer


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6.6.3.2 Protection Policy

Protection and control system used for switchyard of the Project will be designed according to Vietnam standards and regulations of Vietnam Electricity (EVN) as well as applying national standards. Protection and control system used for switchyard of the Project will be designed according to following documents:

Electric protection of MOI - Part IV-11TCN-21-2006

Document No. 5498/EVN-KTSX dated 27/11/2008 of EVN on the manufacture of relays.

(1) Protection Definitions

A fault is an unintended connection which may occur between phases or from phase(s) to ground. Such connection may be solid (zero impedance) or may contain impedance.

The faulty circuit is the smallest part of the system which is bounded by circuit breakers in which the fault is contained.

Reliability is the measure of a protection scheme's ability to operate when required.

Security is the protection scheme's ability to refrain from operating when not required.

Local backup is the facility installed at the local busbar to provide for a single contingency failure of protection equipment by utilizing two independent protection schemes for fault sensing and trip initiation, and a scheme of sequential tripping to cater for circuit breaker failure.

(2) Basic Protection Policy

The basic aim of protection of a switchyard is to provide accurate recognition of a fault condition and to ensure rapid isolation of the faulty circuit from the system.

In achieving this, the protection scheme should embody the following features:

(a) High reliability and security

In the event of a trade-off, the former takes priority.

(b) Fast operating times:

To minimize damage both to the faulty circuit and to the adjacent parts of the system due to the passage of fault current

To maintain system stability.

(c) A complete backup system which employs either a remote protection system or local backup in accordance with standard practices and which will provide fast fault clearance in the event of a single contingency failure of any element of the protected scheme.


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(d) Where necessary, a protection signalling system shall be provided to accelerate tripping, including remote tripping due to local breaker failure.

(3) Protection for Circuit Breaker Failure

Duplicate breaker failure protection shall be applied locally and the necessary relays shall be provided either externally or in-built within protection schemes. Failure of any circuit breaker to trip within its normal time shall result in a local trip and lockout of all the appropriate circuit breakers necessary to isolate the fault.

Duplicate circuit breaker failure intertrips protection signalling via optical fibre to the remote end of the line shall be provided for both of the 220kV Thai Binh TPP to Thai Binh lines. Automatic reclose of remote line circuit breakers shall be blocked following a permissive receipt of a circuit breaker failure intertrip signal.

6.6.3.3 General Specification for Protection Equipment

All high voltage apparatus in the substation and all associated transmission lines shall be protected in accordance with the basic protection policy, Clause 6.6.3.2 (2)

(1) Equipment Considerations

In general, the following considerations shall apply to protection relays and equipment:

(a) Each of the duplicate protections shall be either from different manufacturers, or if from the same manufacturer, shall employ different operating principles. This is to prevent any common mode failure between duplicate protections causing a failure to operate under fault conditions.

(b) Independent duplicate tripping supplies shall be provided from two batteries.

(c) Relays shall be flush mounted in cubicles or on rack type panels.

(d) Each protection system shall be connected to its own separate CT core.

(2) General Protection Relay Requirements

All protection equipment supplied under the Contract shall comply with the requirements of IEC 60255 “Electrical Relays”.

Main protection relays such as line and transformer differential relays, distance relay or overcurrent relay, etc, will be manufactured by manufacturers approved by the Employer such as ABB, Siemens, AREVA, SEL, and Toshiba or equivalent.

Main protection relay should be digital type with interface according to procedures of IEC 60870-5-103, DNP, Modbus, etc.

Type test certificates shall be provided for each type of protection relay proposed for use under the Contract and in particular, the certificates shall indicate that the relays have met the requirements of the following:

IEC 60255-5 Insulation Tests for Electrical Relays


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IEC 60255-1 Measuring Relays and Protection Equipment

IEC 60255-22-1 1 MHz Burst Disturbance Tests

IEC 60255-22-4 Fast Transient Disturbance Test

IEC 60255-22-3 Radiated Electromagnetic Field Disturbance Tests

The relays operating within the voltage range shall not result in a change in accuracy greater than ±5% at any setting.

(3) Relay Settings

The Contractor shall:

(a) Determine the appropriate CT ratios and relay settings for the protection of the equipment.

(b) Provide details of all calculations used to determine the settings for all protection equipment.

(c) In the case of microprocessor based relays, provide a copy of the software for the application of relay settings and remote interrogation.

(d) The Contractor shall make arrangements with the relay manufacturer to supply firmware upgrades to the Employer at no cost where it is can be shown or it is known that a firmware upgrade is essential for the correct functioning of the relay. The upgrades shall be carried out by a change in EPROMS or by downloading the new firmware version from a PC.

(4) Remote Interrogation

Remote interrogation facilities shall be provided (via an external serial interface or equivalent) for the line protection relays.

These relays shall be interrogable either by the power station control and instrumentation system or by separate stand-alone communication facilities.

(5) Protection Analysis and Fault Location

Fault location facilities shall be provided for the 220kV feeders. This may be provided either as a feature of the distance relays or as separate remotely interrogable stand-alone units or as part of the disturbance recorder facility which shall be provided to monitor the equipment. To assist in post fault analysis, fault recorders shall be installed to record waveforms of currents and voltages, and event recording of the status of protection relays, including details of phase and zone of fault as appropriate. This information will be transmitted to the National Load Dispatch Centre (NLDC) and Northern Regional Load Dispatch Centre (NRLDC).

6.6.3.4 Specific Requirements for Protection Equipment

Protection relays shall be of the digital or numeric type and incorporate such features as remote interrogation, fault recording, fault location and self checking.

The relay shall incorporate a self checking feature which continuously monitors or automatically checks at regular intervals the condition of the relay and provides a


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warning of incipient or actual failure by means of an alarm contact which shall be connected to the switchyard alarm system.

Protections shall be mounted in the relay room in cubicles or on rack type framework with links and fuses provided in all protection circuits.

Duplicate protection devices on any one circuit shall be physically separated from each other on the racks or in the cubicles to allow maintenance to be carried out on one protection device without affecting the other protection device.

6.6.3.5 Distance Protection for 220kV Transmission Lines

The relays shall be able to be used with signalling equipment to permit high speed accelerated tripping of the circuit breakers at both ends of the line. To meet system stability requirements fault clearance time at the faulted end of the line shall be not more than 5 cycles and at the remote end, not more than 6 cycles.

The relays shall include all the necessary scheme options to permit selections to be made for permissive under reach, permissive overreach, or blocking, and weak-infeed. To cater for the failure of a tower which may result in total loss of protection signalling, it is preferred that one of the distance schemes be configured in a blocking mode.

Duplicate local backup for 220kV circuit breaker failure shall be provided with permissive (fault detector checked) transfer tripping to the remote end using optical fibre where provided. For low level faults associated with breaker failure where it may not be possible to achieve permissive transfer tripping, the security of the transfer trip signal shall be ensured by a 0.5 second Timer Check.

Any additional equipment required for the correct functioning of the line protection shall be provided by the Contractor.

6.6.3.6 Busbar Protection

Low impedance busbar differential relays shall be used for the protection of high voltage busbars. The differential relay shall be stable for external faults. The operating time shall be less than 30 milliseconds and the busbar protection shall be capable of detecting all combinations of phase-phase and phase-earth bus faults within the protected zone.

(1) Each of the 220kV busbars shall be protected by two high speed, low impedance protections (busbar differential relay)

A bus fault associated with line circuit breaker failure shall initiate a permissive transfer trip to the remote end of the line. Circuit breaker failure protections shall be duplicated.

(2) The 220kV connection between the generator transformers and the switchyard shall be protected by duplicate protections comprising high speed, high impedance protection. Alternately, the 220kV connections shall be included in the generator transformer protection. Duplicate circuit breaker failure protection shall be provided.


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6.6.4 Equipment layout in the switchyard

In the switchyard there is one switchgear section of 220kV. Refer to Volume 9 Drawings.

6.6.4.1 220kV Equipment

(1) The 220kV switchgear equipment in the switchyard includes: circuit breakers, disconnectors, current transformer, voltage transformer, supporting insulators, towers, arms, feeders and busbars etc.

(2) Busbars are 2 x AAC 910.

6.6.5 Measurement, control and protection system

6.6.5.1 General

Rated frequency 50Hz

Rated input current 1A

Rated input voltage 110V AC

Auxiliary voltage 220V DC

Mounting of equipment

Control equipment Front of cubicle

Protection equipment Inside of cubicle

Relay:

Type of digital with microprocessor manufactures should be approved by the Employer.

Applied standards of protection relays: IEC 60255

Level of protection:

Indoor cubicle IP41

Outdoor cubicle IP55

Cubicles shall be equipped with thermostatic controlled heating elements and door controlled operated lights.

The circuit breakers, disconnectors and earthing switches shall be provided with a mechanical and electrical interlock mechanism.

6.6.5.2 Switchyard control system

A computerized control system shall be equipped for the switchyard of the Project. This system is used to do control, monitoring, data acquisition, measuring, signalling functions for the substation complying with the relevant parts of IEC 61850. This system shall also perform communication functions between NLDC and substation via the SCADA system complying to standard IEC 60870-5-101. The control system shall meet the following requirements.


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(1) Basic conditions

The computerized control system shall be designed by the same computerized control system manufacturer as for the whole plant, for easy operation. The applied design standards are international standards. The system shall be suitable for the operation of high voltage switchyards.

The control system is a distributed system that means each control unit is physically separate. The control units shall be connected to each other through a local area network (LAN).

(2) Basic principles:

(a) The principle of switchyard control is that failure of any single control unit shall not affect main high voltage switchgear equipment and not affect the whole control system. The incidental action of operator on control system (change, installation etc.) shall be minimized.

(b) The complete computer system and peripheral equipment shall conform to international standards and be made up of the latest generation of equipment. The computer control system is configured by modules to allow for flexible installation, operation, replacement, expansion and upgrading in the future. Optical fibre cable is to be used for connection between control equipment. Communication procedures shall comply with international standards.

(c) Maintenance, replacement and expansion of system components shall not lock the whole control system.

(d) The control system shall be designed to derive power from the switchyard auxiliary power system.

(3) Mimic displays consisting of simplified overviews and detailed bay diagrams identifying all H.V. operational equipment shall be supplied.

(4) Operator control of circuit breakers and motorized disconnectors shall be possible from the switchyard control room, the PCR and NLDC via SCADA connection.

(5) Dual return status for all controllable high voltage switchgear.

(6) Dual indication for all other high voltage Plant, such as earth switches.

(7) Display and trending of analogue data.

(8) High speed Sequence Of Event (SOE) recording to 1 mS resolution with clock synchronised to the GPS system.

(9) Auto-reclose on all feeders with facilities for dead line, dead bus or check synchronising as appropriate.

(10) Automatic synchronising.

(11) Switchyard alarms shall be displayed and logged by the system to identify all abnormal conditions experienced by switchyard apparatus, auxiliary services and power supplies (AC and DC), control, protection and communications systems.


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(12) Switchyard status changes such as protection relay flags and output signal indications that are necessary to clearly identify the correct sequence of protection operation for a H.V. system fault shall also be logged.

(13) Control equipment connections to the switchyard apparatus shall be designed to interface to conventional CT and VT contacts and coils as well as transducers.

(14) Remote control will be initiated through the operator VDU interface but backup electrical control of circuit breakers and switches shall be provided such that no single failure will affect both normal and backup positions. Minimum backup for controls is a control switch for breaker operation and an ammeter for indication. The control switch shall be such as to prevent inadvertent or accidental operation. Where synchronising is required, synchronising facilities for the backup controls is also required.

(15) Control for motor driven earthing switch is carried from control system of power plant.

(16) Interface to the NLDC and NRLDC:

Supervision:

(a) Status indication of: circuit breaker: OPEN/CLOSED, disconnectors: OPEN/CLOSED, earthing switches: OPEN/CLOSED

(b) Signalling: switchyard alarms including but not limited to:

Circuit breaker low gas pressure

DC system fault

AC system fault

Communication fault

Line protection fault

Main protection trip, etc.

(c) Measured values:

For busbar: frequency f (Hz), voltage U (kV)

For 220/6.6-6.6kV transformers: current I (A); voltage U (kV), active power P (MW), reactive power Q (MVar), tap changer position.

For transmission lines: current I (A); voltage U (kV), active power P (MW), reactive power Q (MVar).

(17) Functions of computer control system:

(a) Control function

Control functions include:

Opening - closing equipment: motor driven circuit breakers, disconnectors and earthing switches.

Controlling on load tap changers.


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Cooling system for transformers.

The switchyard control is performed by computer control system at 5 levels:

Level 1 From NRLDC and NLDC through SCADA.

Level 2 Control from the PCR of the plant by ICMS.

Level 3 Control from switchyard level. Substation level is performed at switchyard control room with server computers, operation station, and LAN network with communication protocol IEC 61850. The operation station must be able to perform all control and supervisory functions of all active equipment within the switchyard. Switchyard level shall communicate with higher level SCADA.

Level 4 Control from bay level. Bay level, is installed with I/O sets to assemble and process digital and analog data of bay. I/O sets are fixed on control-protection cubicles and connect to LAN network. I/O sets have control functions to enable opening/closing of circuit breakers, motorized disconnector switches, and earthing switches as well as being able to control transformer on load tap changers. Bay control unit display screens will show switchyard single line diagram, position of circuit breaker, disconnector switch, earth switch, measurement parameter of bay, etc.

Level 5 Control at equipment level shall be performed by control switches/button devices on switchgear (circuit breaker, disconnector switch and earthing switch).

The program determining the priority for each control level cannot be controlled from two different locations at the same time. The status of controlled equipment shall be displayed on the screen. The control software is able to select or cancel operation command, reject commands causing faults, unsafe operation for the power system in general and the switchyard in particular.

(b) Measurement signal:

Measurement signals and data shall be recorded in real time. This data shall be stored in a database forming part of the Switchyard Control and Monitoring System (SCMS). The following information can be viewed on the screen or printed out:

Current operating scheme of the switchyard and state of equipment including

Circuit breakers, disconnectors and earthing switches.

Tapping of the transformer on load tap changer.

Operating states (local/remote etc.) of switchyard components (circuit breakers, transformers, auxiliary sources etc.).

Operating states of control equipment.


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Measurement data U, I, P, Q, f, Wh, VARh of electric components such as transformers and outgoing circuits.

Alarm data.

Reporting (performance data, equipment state and emergency data).

(c) Storage and treatment of data function

The data includes operating parameters, measured values and status of equipment which shall be transmitted to the main computer and saved in the memory in real time.

Record data and event sequence, prior to, during and after a system disturbance, irregular operation state or fault occurance.

Each action of operator shall be recorded in the operation diary.

(d) Data processing function

Necessary calculations shall be conducted regularly for received information. When there is irregular information, it should be recorded and alarmed to operators (example: overload, AC or DC source shut-down, transformer oil temperature, etc.).

Time shall be synchronous for all system equipment via GPS clock.

The above information can be studied at any time through computers or print outs, as well as being able to copy and store the information on floppy discs or other removable media for other uses.

(e) Interlock function of circuit breakers, disconnectors and earthing switches.

This system will use the above information in order to perform the interlocking function in actuation of switching units according to the correct orders of hierarchy.

(f) Monitoring and relay adjustment function:

The system shall be in contact with the switchyard protection relay system. With capacities of:

Observation and monitoring of relay data.

Adjustment of relay data.

(g) System interface and extension

The computerized control system is equipped with ports for being able to interface to SCADA system of NRLDC and NLDC with the current version (complying with the national standards).

(h) Self test function:

The system shall have self-test function for all hardware & software and shall alarm when a fault or abnormal state occurs.


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(i) Configuration and technical requirement:

The SCMS shall operate according to the control configuration of the power station ICMS.

6.6.5.3 Protection - Automatic equipment

The methodology for automatic protection of switchyard equipment is as follows

(a) 220kV Transmission line feeder:

220kV Transmission line feeder is installed 2 sets of protection as:

* Protection No 1 integrated function protection as:

Line differential protection (87 L) with teleprotection interface (85) by optical fibre

Directional overcurrent protection and earth fault protection (67/67N)

Instantaneous and time overcurrent and overcurrent earth fault protection (50/51) (50N/51N)

Breaker failure protection (50 BF)

Trip circuit supervision

Test block

Auxiliary relays, time relays, fuses, links, terminal blocks, labels, conductors for connecting cubicle internals etc.

* Protection No 2 integrated function protection as:

Distance protection (21/21N) with teleprotection interface



Synchrocheck and reclosing (25/79)

Low voltage and high voltage protection (27/59)

Fault recorder (FR) and fault locator (FL)

Power swing protection


Test block


(b) Station transformer ST 220/6.6-6.6kV:

ST-220/6.6-6.6kV is installed sets of protection as:

Differential protection with restricted earth fault protection (87T, 64) and fault recorder (FR)


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Instantaneous and time overcurrent and overcurrent earth fault protection (50/51) (50N/51N)

Over load of transformer (49)


Auxiliary relay and signal relay of transformer protection: Buchholz relay, oil temperature relay, oil level, windings temperature

Trip/lockout relay


Test block


(c) 220kV side incoming feeder of ST- 220/6.6-6.6kV:


Instantaneous and time overcurrent and overcurrent earth fault protection (50/51 & 50/51N)

Breaker failure protection (50BF)

Busbar voltage selection circuit suitable with disconnecting switch position

Auxiliary relay to trip/lockout


Test block


(d) 220kV Busbar protection:

220kV busbar has two sets of independent busbar differential protections which operate with Low or high impedance principle and operates each feeder by module. Busbar protection cubicle is to be convenient for expansion in the future as planned.

Accessories: MCBs, auxiliary current transformers, busbar selectors, auxiliary relays, test blocks, terminal blocks, labels, conductors for connecting cubicle internals etc.

(e) Fault Recorder cubicle:

220kV transmission line feeders and ST-220kV transformers will be equipped with fault recorder systems which records the currents and voltages in the process of a fault occurring and record the active time of relay protection, etc.

Record system of transient process is composed of the following :

Record transient process set.


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Microprocessor set

Computer set: CPU, screen, keyboard, printer, fault analysis software, etc.

6.6.6 Auxiliary systems

6.6.6.1 AC - DC auxiliary power sources

(a) AC auxiliary electrical system is a 400/220V AC system consisting of two independent distribution busbars supplied from two independent AC sources from the power station auxiliary systems:

All AC auxiliary demands of the switchyard are capable of being supplied from either of the two independent busbars and are protected by MCBs.

Coupling of two auxiliary busbars is equipped with coupling busbar’s MCB with 2/3 electrical interlocking diagram and F27, F59 protection relay.

AC cubicles are placed in AC/DC room in the switchyard control building.

The 230/400V AC loads of the switchyard are as follows:

Motors for cooling transformer

Motors for on load tap changers

Motors for operating drive mechanism of circuit breakers, etc.

Lighting for switchyard.

Electric power for environmental equipment such as heaters, lighting, ventilation, air conditioner for cubicles.

(b) 220V DC auxiliary electric source consists of two independent busbars, which are supplied from two 220V-300Ah independent battery sets. These battery sets are charged by two battery chargers.

DC auxiliary demands of substation are supplied from two independent busbars and are protected by MCBs.

Coupling of two auxiliary busbars is equipped coupling busbar’s MCB with ACO diagram and F27, F59, F64 protection relay.

DC cubicles is placed in AC/DC room in the switchyard control building

The 220V DC auxiliary loads include:

Signal circuits

Control circuits

Actuation circuits of circuit breakers.


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(c) The AC and DC circuits in the switchyard are fed from separate power sources from the station auxiliaries source and power supply circuits shall be able to take power from one of two power sources.

6.6.6.2 Charger

Input voltage: 400/230 10%V AC, 50 5% Hz

Output voltage: 220 1,5%V DC with load 0-100%

Rated current: 63A.

6.6.6.3 Battery

Acid, sealed type.

Rated power for 8h: 300 Ah

Rated voltage: 220V 10%.

6.6.7 Lightning Protection system

In order to protect against over-voltage waves transmitted through transmission lines into the transformer, all the high and medium voltage sides of the transformer 220kV/6.6-6.6 kV and 220kV outgoing feeders shall be equipped with surge arresters.

- Direct lightning protection

Earth wires are used for protecting against direct lightning strikes. They are set on gantry structures in the switchyard.

220kV switchyard uses earth wires at the top of 220kV gantry structures, at a height of 22m. They shield all equipment up to 17m.

Details of earth wire and lightning rods arrangement as well as areas shield reference in Volume 9 Drawing. The protected areas shield all equipment and items in the switchyard.

- Overvoltage wave protection: overvoltage wave protection from OHL to the switchyard and the Plant by using ZnO surge arrester:

At the ends of 220kV transmission line

High-medium-low side of GT1-GT2, and Station Transformer

6.6.8 Electrical Works

6.6.8.1 Extent of Work

The Contractor shall design, supply all materials and construct the electrical works and miscellaneous minor works for the switchyard.

This shall include, but not be limited to the following, together with any other items deemed necessary to complete the switchyard:

(1) H.V. busbars and connections.


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(2) Kiosks.

(3) L.V. cabling.

(4) Earthing.

(5) Lighting.

(6) AC and DC distribution.

(7) Batteries and chargers.

(8) Cubicles in relay room.

The Works shall comply generally with Volume 2 and specific requirements for the switchyard as provided in the following Clauses.

The erection of major items of H.V. electrical Plant is covered by Clause 6.6.2.

6.6.8.2 General Specification

6.6.8.2.1 Labels

Identification plates shall be attached to each item of H.V. equipment and to kiosks and boxes. This plate shall have a short description of the function of that equipment, kiosk or box and the circuit in which the equipment is connected. For equipment involved in switching operations, the description shall contain an operating number which will become the basis for identification of this equipment in control, indication and operation functions for the switchyard. This operational numbering system will be provided by the Employer.

Coloured phase identification plates shall be installed on:

(1) Each side of each circuit breaker.

(2) Each disconnector.

(3) Each voltage transformer.

(4) Each set of longitudinal busbar supports.

Plates shall be attached to the outside of switchyard enclosure walls and gates warning of the danger of high voltage equipment within the switchyard. Standard design of plates shall be used if available.

Clause 6.6.8.4 specifies labelling of marshalling kiosks.

6.6.8.2.2 Painting

All outdoor metal surfaces, as far as is practical, shall be galvanized, either by hot dip galvanizing in accordance with Volume 2 or by use of galvanized sheet steel.

Ungalvanized metal surfaces shall be provided with an effective vapor sealing paint finish, applied in accordance with the best trade practice and generally in accordance with Volume 2.

Before painting, all ungalvanized parts shall be completely clean and free from rust, scale and grease and all external rough metal surfaces on castings shall be filed.


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The paint system shall be in accordance with best practice for hot and humid locations.

All external surfaces shall receive a minimum of three coats of paint. The primary coat shall be applied immediately after cleaning. The second coat shall be of an oil and weather resisting nature and of a shade of colour easily distinguishable from the primary coat.

The final coat shall be of glossy oil based and weather resisting non-fading paint of a grey Colour.

Switchboards and cubicles shall be thoroughly degreased and passivated followed by a corrosion inhibiting primer undercoat and finish coat. The inside of cubicles shall be painted white, the outside colour shall be nominated by the Employer.

6.6.8.3 Busbars and Connections

Busbars and electrical connections in the switchyard shall have ratings as specified in Clause 6.6.1.2 and be in accordance with IEC 61089 in respect of current rating and material analysis. The conductor used shall be ACSR/GZ and a common size shall be used for all connections.

Provision shall be made for expansion and contraction with variation in conductor temperature. The design of joints and connections shall be such as to permit ready dismantling.

Busbars shall be in continuous lengths between supports. Connectors for the aluminium conductor shall preferably be compression type, and if necessary shall be type tested.

Unless otherwise approved, busbars and connections shall be so arranged and supported that under no circumstances, including short circuit conditions, shall the clearances between live metal and earthed metal work or between conductors be less than the specified distances.

Overhead conductors carried by the switchyard structures shall be erected with sags and tensions to suit the electrical clearances in Clause 6.6.1.3. The design shall allow for forces due to short circuit, wind and seismic loadings.

Disc insulators for overhead busbars shall be porcelain or toughened glass, ball and socket type complying with the relevant parts of IEC 60383 and shall be tested in accordance with this standard to meet the design parameters specified in Clause 6.6.1.2 and mechanical requirements of the design. Type test certificates shall be provided.

Overhead earth wires shall also be erected with sags and tensions to suit the electrical clearances in Clause 6.6.1.3. The earth wires shall be connected to the steel strain structure to provide a connection to earth through the structure.

Overhead conductors shall be strung preferably before the erection of switchgear, busbars or other equipment in the switchyard.

When dissimilar metals are in contact, approved means shall be provided to prevent electrochemical action and corrosion. Unless otherwise approved by the Employer, joints and surfaces of copper or copper alloy fittings shall be tinned.


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Suspension and tension conductor clamps shall be of approved types and shall be as light as possible. They shall be designed to avoid any possibility of deforming the stranded conductor and separating the individual strands.

Tension conductor clamps shall not permit slipping of, or damage to, or failure of the complete conductor or any part thereof at a load less than 95 per cent of the ultimate strength of the conductor. Clamps and fittings made of steel or malleable iron shall be galvanized. All bolts and nuts shall be as specified and shall be locked in an approved manner.

For inter-equipment connections with two or more conductors per phase, spacers shall be installed at approximately 1 meter intervals to restrain dynamic short circuit forces. The number of spacers in overhead spans shall be determined by taking into account the avoidance of conductor abrasion during low velocity wind conditions, and limiting the total tension in the span and on the supporting structure during short-circuit conditions.

Care shall be taken to ensure that conductors are not damaged in any way. They shall be free of scratches, cuts, protruding strands, bird caging, deposits of grease or dirt, deformation or adhesion, which could increase corona discharge or radio interference.

If the conductors are laid on the ground for erection purposes, they shall be protected by hessian or timbers and shall not be moved unless raised clear of the ground. No vehicles shall run over and no person shall walk on the conductors.

If the conductors are found to be damaged to a degree that simple cleaning or polishing will not rectify the imperfections then the Contractor shall replace the defective sections.

The Contractor shall determine the length required for each A.C.S.R. connection so that when erected there is no bird caging of the conductor. The ends of the conductors shall be cleaned by wire brushing, the terminating clamps fitted and bolted to terminal palms or conductors. Where a tee or parallel connection is to be installed, the conductor at this joint shall also be cleaned by wire brushing.

Before any aluminium contact surface is bolted, a liberal layer of aluminium jointing compound shall be applied to each contact surface.

Where tubular aluminium busbars or connections are used, they shall be erected and all necessary adjustments made on the equipment and/or supports so that they are straight, in line and level before any Site welds are carried out. Tubular aluminium busbars are preferred for the switchyard with bolted clamps for joints in the busbars.

Where Site welds are required, the Contractor shall ensure that the busbars bed truly in the supports and if necessary the busbars shall be supported in mid span so that after welding a minimum and uniform sagging is achieved.

Erection of the busbars and connection shall not result in any load being placed on equipment or supports other than the dead weight of the busbars and connections.

All surfaces which are likely to rub due to thermal expansion shall be liberally coated with graphite.


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6.6.8.4 Kiosks

For each circuit switchbay, a marshalling cubicle or kiosk shall be provided for the marshalling of all ancillary equipment cabling associated with the circuit, e.g., busbar and line disconnectors, current and voltage transformers, etc., to be routed by trunk multicore cables to remote control and relay panels in the switchyard control building.

Alternatively, the Contractor may decide to marshall cabling within the relay room and provide small CT and VT marshalling boxes and AC and DC distribution boxes throughout the yard.

Busbar protection CT summation kiosks shall be provided to marshall the CT cabling for each section of busbar. Each circuit shall be provided with isolation links and be clearly labelled.

The kiosks shall be free-standing and of weatherproof and vermin-proof galvanized sheet steel or aluminium construction. The degree of protection shall be IP54 rating to IEC 60529. They shall be mounted at ground level.

A kiosk for the marshalling of all cabling going from the switchyard to the power station proper, with the exception of control system cabling, shall be provided and mounted in the relay room. The finish of this kiosk shall be compatible with other protection and control cubicles in this room.

Kiosks shall be provided with the necessary terminal blocks, cable gland plates, etc., for termination of multicore cables.

One fire protection equipment kiosk shall also be provided at each end of the switchyard to house portable and mobile fire extinguishers, hoses, drums, etc. required for fighting fires in the switchyard. The kiosks shall be painted red and shall be equipped by the Contractor with suitable locally available equipment.

All kiosks shall be labelled on the front door with a description approved by the Employer. Labels shall be non-corrosive, non-hygroscopic with lettering of a contrasting colour and of an appropriate size.

6.6.8.5 L.V. Cabling

The Contractor shall design a cabling system for the effective control and protection of all items of equipment. All cabling shall be PVC/PVC insulated cable except connections between terminals in the same item of equipment, cubicle, kiosk, box or panel, which shall be single core PVC insulated cable.

Manufacturing requirements for L.V. power and control cables, telephone cables and communication co-axial cables are specified in Volume 2.

6.6.8.5.1 Conduits

Cables shall not be buried directly in the ground. Between cable trenches and switchyard equipment and between items of equipment cables shall be installed in heavy duty UPVC conduit to IEC 61386 and be of a minimum 100 mm diameter. The top of the conduit shall not be less than 300 mm below the surface of the sub


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grade. A cable pulling pit shall be constructed every 50 meters or less and wherever conduits change direction.

Conduits shall be terminated at items of equipment using a haunch. Where conduits terminate in cable trenches they shall be bell-mouthed.

Conduits will generally not be required for L.V. cables installed between ground and equipment boxes. If additional mechanical protection is required, heavy duty UPVC and other flexible conduit shall be used. Metallic flexible conduit shall be galvanized or non-ferrous.

Holes drilled in steelwork members for the attachment of conduits shall be treated with a corrosion inhibiting compound.

At the completion of cabling, cable haunches shall be sealed with 6:1 sand cement mix or an approved cold setting compound 25 mm thick and crowned to drain.

6.6.8.5.2 Installation of Cabling

Cables shall be installed in the switchyard and between the switchyard and the power station buildings generally in accordance with Volume 2.

The Contractor shall produce cable schedules showing full details of each cable including cable number, core size, number of cores, type of cable, route information and other details deemed necessary for cable identification and tracing. Each cable shall have a unique number and a logical numbering system shall be developed.

Cables between connection boxes and the ground not enclosed in conduit shall be secured to the supporting structures using approved cable cleats with saddles.

Cables entering marshalling kiosks shall be suitably grouped and the space surrounding them either in the base of the kiosk or in the opening at the top of the kiosk footing shall be blanked off by pieces of plasterboard or approved alternative, cut approximately to the shape required. A pliable mix of cement, sand and vermiculite (1:2:4) shall then be packed about the cables and on top of the plasterboard to a depth of approximately 50mm to provide a satisfactory air and vermin seal from the trench entry.

A seal shall be placed on cable trenches where they enter buildings. The seal shall take the form of a removable 3mm thick aluminium plate positioned across the trench 50mm above the cables and attached to the trench walls at the point where the trench enters the building, the gap between the plate and cables being sealed off with a (1:2:4) mixture of cement, sand and vermiculite 150mm thick. Alternative methods of forming this seal will be considered by the Employer.

6.6.8.5.3 Termination

Spare cores shall be left long enough to reach the furthest terminal on the item of equipment and shall be insulated and safely and neatly secured to their parent cable. As a rule, 20 percent spare cores shall be allowed for in a multi-core cable except where there is no possibility of future requirements e.g. CT and VT cabling.

The type of lugs used to terminate wiring shall be of the pre-insulated compression type, which grip the insulation as well as the conductor.


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Wires terminating at pinch-screw type terminals shall be fitted with a sleeve connector to protect the wire against damage. Where the terminal is fitted with a pressure plate, the sleeve is not required and the wire shall be terminated bare. These terminating on pin-strips shall be soldered.

The Contractor shall supply and fit to all terminations, approved flexible plastic slip-on type wire identification ferrules with a wire number as shown on the schematic diagrams. The numbering system for all terminations shall be in accordance with IEC 81364.

Telephone type cabling shall be terminated by a technician experienced in telephone wiring and in accordance with an approved Colour coding scheme. Identification ferrules are not required.

6.6.8.6 Earthing System

6.6.8.6.1 General

The design and installation of the earthing of all equipment and of the earthing system’s electrodes and connections shall be in accordance with the recommendation in the "Guide for Safety in Substation Grounding" IEEE No. 80, Vietnam standards and regulations and the requirements of Volume 2.

6.6.8.6.2 Installation

The earthing system of the outdoor switchyard is designed following the electrode-conductor earthing system. The earthing grid uses 300mm2 section copper conductors and 22mm copper electrodes which are 3m in length. Earthing grid is embedded at a depth of 1m. Earthing conductors and earthing electrodes are connected together by electric welding. Earthing resistance of the switchyard is calculated to ensure the requirement of the standard: Rd < 0.5. All equipment in the switchyard is earthed and connected to the earthing system of the switchyard by 95mm2 section copper or equivalent galvanized steel cable or bar for above ground connections. Earthing system of the switchyard will be connected to earthing system of the plant.

Except as hereunder provided, the earth grid shall be installed after all civil works have been completed. The conductor shall be laid at a minimum depth of 450 mm below the finished earthworks levels. The grid shall be run across the tops of foundations.

Where the earth grid passes under cable trenches, roads or foundations, the Contractor shall install earthing conductor on the base and up the sides of excavations before concrete is poured or base course placed.

If the design requires deep electrodes to be installed, a hole of minimum diameter 75 mm shall be drilled to the required depth, a galvanized steel strip inserted leaving 500 mm above the ground and the hole filled with a suitably slurried 50-50 mixture of Bentonite and gypsum.

To minimise touch potentials earth mats shall be positioned near the operating handle or operating mechanism cubicle of disconnectors and earthing switches such that an operator's feet are on the mat when operating the handling or touching


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the operating mechanism cubicle. The earth mat shall be bonded to the handle and not directly to the earth grid.

Supplementary earth electrodes shall be 15 mm diameter copper rods of a length to suit the earth grid design.

6.6.8.6.3 Portable Earthing Attachments

Provision shall be made at the following positions for the attachment of portable earths:

(1) As close as practicable to earthing switches to permit maintenance to be carried out upon the switches.

(2) Every section of bus or an associated busbar connection.

The design of the attachments shall suit the type of portable earths used by the Employer.

6.6.8.7 Switchyard Lighting

Outdoor lighting system is arranged on three lighting towers with height of 20 m. Each tower has a panel of 6 headlights with capacity of 500W each. The control board of each lighting panel is arranged at the feet of lighting tower at the height of 1.35m. Lighting cable is of steel wire armour. Cable on the tower is put in the steel conduits. A lighting system shall be supplied for the switchyard which provides an illumination level of approximately 15 lux for high voltage Plant, and operational labels and access ways throughout the switchyard. A level of 3 lux shall apply to other areas to provide security of the Site.

Either high or low level lighting, or a combination of the two, is acceptable. The design of high level lighting shall be such that re-lamping does not require an outage of H.V. equipment.

The lighting shall be supplied from the 400/230 V AC distribution boards, with the load divided equally between the two boards and the circuits arranged such that a loss of a circuit will not cause all lighting in a section of the switchyard to fail.

6.6.8.8 L.V. AC Switchyard Power Outlets

400/230 V AC switchplug outlets shall be provided to service various maintenance, testing and operation functions in the switchyard as follows:

6.6.8.8.1 100A Outlets

400V 100 A continuous rated switchplug outlets with connections for 3 phases, neutral and earth shall be supplied from the AC distribution boards and installed in each switchbay for H.V. testing of Plant and CT injection testing.

6.6.8.8.2 15A General Purpose Outlets

230V, 15A outlets shall be provided throughout the switchyard as follows:

(a) Two installed in each H.V. circuit breaker control box.

(b) One in each disconnector control box.


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(c) One in each bay marshalling kiosk.

(d) One in each busbar protection summation kiosk.

The circuits for these outlets shall originate from the AC distribution boards in the switchyard building.

6.6.8.9 Building Equipment

Rooms in the switchyard building shall contain equipment as detailed below.

The control room shall contain the switchyard control system cubicle, racks or cubicles as specified in Clause 6.6.3.

Clearances around cubicles for operational, testing and maintenance requirements shall be as follows:

1. 800mm minimum between wall and rear of cubicle where access only is required to rear of cubicle; 1700mm where wiring or other work may be required.

2. 1700mm minimum between front of cubicles and walls and other cubicles

All cubicles in the room shall be painted the same colour.

6.6.8.10 220V DC Distribution Boards

Two 220V DC distribution boards shall be provided in the control room to supply all switchyard equipment, control, protection and emergency lighting requirements. The equipment for the board may be cubicle mounted or rack mounted.

Each board shall be connected to a battery and a switch provided on one of the boards to parallel the two systems in the event of one of the batteries being rendered unserviceable or when a boost charge is necessary.

Other features to be included on the boards are:

(1) Battery earth fault system consisting of a relay and a centre tapped resistor which is connected between the positive bus and negative bus.

(2) Battery voltmeter selection switch and voltmeter wired to indicate positive to negative, positive to earth, negative to earth.

(3) Ammeter measuring input amperes.

6.6.8.11 400/230V AC Distribution Boards

Two AC distribution boards shall be supplied and installed in the control room. The outgoing circuits shall be arranged to allow for the redundancy of one board. The equipment for each board shall be cubicle mounted.

These boards shall be supplied from the power station 400V station auxiliary switchboards and shall supply all 400/230 V AC requirements in the switchyard. The construction of the switchboards shall be generally as specified in Volume 2.


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The switchboards shall incorporate circuit breakers of the appropriate current rating for each subcircuit. Spare circuit breakers shall be installed for possible future requirements.

The neutral busbar shall have a rating of not less than that of the associated phase busbars.

Supply contactors shall be provided to automatically switch the other supply to a board in the event of loss of the normal supply.

The following features shall also be included:

(1) Voltmeter indicating busbar phase to phase volts.

(2) Ammeter indicating current in one of the phases.

(3) Switches to isolate each incoming supply.

(4) Indicating lamps for each incoming supply.

(5) Busbar supervision relay with alarm contact.

(6) High temperature thermostat, set at 45°C, with alarm contact.

(7) Earth leakage circuit breaker.


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6.7 COMMUNICATION SYSTEMS


6.7.1 Scope of Supply

Communication and monitoring system for the Project shall be installed as the following items:

6.7.1.1 SDH (Synchronous Digital Hierarchy) telecommunication system for connecting the

Project to the national power network.

The system is required to provide the following communication channels:

Supply transmission channels for protection relay system between the Project and the related station (Thai Binh 220kV substation).

Supply transmission channels to serve supervision - dispatch - control system:

Transmission channels for hotline telephone between the Project and NLDC (A0) and NRLDC (A1).

Transmission channels for SCADA between the Project and NLDC (A0) and NRLDC (A1).

6.7.1.2 Inside-Plant Communications System

The system shall consist of all provisions necessary to service the following:

Communication between shift engineers and shift staffs in production areas in the plant (boiler, turbine, CHP, etc.).

Management communication between areas in the plant.

Person-seeking announcement and production information (public address system).

Mobile communication between areas in the plant

Image monitoring of the plant

The Contractor, after having done his survey work, shall co-ordinate his work with the Employer and the Employer’s subsidiaries such as EVN Telecom, NLDC (A0), NRLDC (A1) and Power Transmission Company No. 1 (PTC1) in order his design, supply, installation, testing and commissioning of the communication and SCADA/EMS systems are compatible with the existing EVN’s network.

The Contractor shall design, procure materials, install and test the complete items of communication and SCADA/EMS systems as follows, but not limited to:

STM-4/ADM equipment at Thai Binh 220kV switchyard.

MUX/PCM 2x2 Mbit/s (electrical interfaces) at the Site.


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Teleprotection

Modems

Non-metallic optical cable unit.

ODFs, patchcords, JBs

Main PABX, capacity of 700 ports; back-up PABX and subscriber network

Public address system

Supervision camera system.

UHF radio and paging system.

Local area network.

DC-48V power supplies, grounding and lightning protection for above communication systems

Necessary equipments and remote-end integration for connection between the power plant DCS (gateway) and EVN’s SCADA/EMS system.

CCTV system including all cameras, monitors and recording equipment.

6.7.2 Equipment Operating Conditions

6.7.2.1 Operating Conditions

(a) Working temperature range

(i) Performing to Specification: Refer to Volume 2

(ii) Operational: Refer to Volume 2

(b) Supply output voltage range

Performing to Specification: Contractor to state

Operational: Contractor to state

(c) Current consumption: Contractor to state

(d) Noise potentials impressed by equipment onto the -48 V DC power supply:

Psophometrically weighted to CCITT

Rec O. 41 Blue Book Volume 4

Fascicle IV.4, 1988: less than 0.5 mV

Flat above 3 KHz: less than 1.0 mV

(e) No damage to equipment if equipment is subjected to an impulse on the supply of 5.0 kV peak 1.2/50 microsecond of either polarity with a source energy of 0.5 joules.

(f) Equipment tolerance to EM radiation better than:

10 KHz to 250 MHz : 2 mV/m


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Over 250 MHz : 0.5 mV/m

(g) Be immune to, or be fitted with ancillary equipment to protect against the effects of:

Lightning strikes;

Stray electromagnetic fields;

Electrostatic fields;

DC voltage surges on external lines;

Earth grid voltage rise;

Low frequency induction on external lines;

Power supply voltage and current surges;

Card failure or mal-operation on extraction/insertion with power applied.

Terminals carrying potentially lethal voltages (greater than 32 V AC or 115 V DC) shall be covered and have a caution label attached.

All equipment must comply with relevant technical regulations and standards and must be approved by the Employer.

6.7.2.2 Equipment Racks and Cubicles

All equipment shall be supplied mounted on steel equipment racks or cubicles of maximum height of 2750 mm. All non-equipped space on the racks or cubicles shall be covered with blank panels.

All equipment racks or cubicles shall be supplied complete with mounting hardware appropriate to the height of the rack or cubicle and the overhead cable runways. Suitable arrangements shall be made for the support of all cables leaving the cable runway to the equipment rack or cubicle.

All racks and cubicles shall be earthed to the station electrical earth.

6.7.2.3 Equipment Alarms

All equipment shall include (where applicable):

(a) Local alarm/status/control display;

(b) Interfaces for extension of alarm/status/control to remote master; and

(c) Group (urgent/non-urgent) alarm interfaces for local extension within the Site.

6.7.2.4 Communication Room Facilities

(a) Communication Room in the Central Control Building

The room has to ensure environment conditions according to TCN 68-149:1995 standard:

Equip precision air conditioning.


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Temperature: 5°C 27°C.

Relative humidity: max. 80% at the whole temperature range.

Equip CO2 fire extinguisher.

The room shall be designed to minimize dust ingress. Access doors and corridors shall be of sufficient size and layout to allow access for 2750 mm communication racks and other communication equipment.

Racks shall be arranged in the room 1.5 m apart for ease of rack manoeuvring and access to the front and rear. The room shall accommodate the main exchange, a duplicated power supply and an alarm system.

Plinths shall be placed under the racks, packed to keep them level.

Access shall be provided for cables entering and leaving the room.

(b) Cable Runways

Cable runways, cable trays or cable mesh to run cables between racks shall be provided in the room over each bayline, and shall be interconnected with each other and extended to the main distribution frame and to the cable entry points to the room. Separate runways or conduit shall be provided for AC mains cables.

All cable runways shall be earthed to the station electrical earth grid. The Contractor shall provide earthing details for approval by the Employer.

(c) Main Distribution Frame (MDF)

The MDF shall be installed in the room and shall use insulation displacement technology in modular format. Sufficient 600 pair verticals shall be supplied and installed to cater for the termination of all multiplex channels. Provision shall be made in the design to cater for the number of jumper wires interconnecting the services to the multiplex channels.

The MDF shall be earthed to the station electrical earth grid.

(d) Miscellaneous Equipment Racks (MERs)

MERs shall be placed strategically in the baylines to accommodate the DC distribution panels, alarm panels, and any other general apparatus that may be required.

(e) AC Supply

The Contractor shall supply a wall mounted AC distribution circuit breaker panel to provide for the AC distribution within the room. Suitably rated circuit breakers shall be supplied and installed to cater for the 50V modular power supplies and other AC loads.

50% spare capacity of circuit breakers shall be provided.

General purpose 230V 10A twin socket wall outlets shall be provided at each end of each bayline to power test equipment etc.

(f) 48V DC Distribution


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Distribution shall be through circuit breaker panels and further distribution for minor circuits through fuse panels. Spare capacity shall be provided.

(g) Alarm Requirements

A bay alarm panel shall be supplied and installed on each MER to cater for all equipment alarms generated within the bayline. Equipment alarms shall be accepted causing a LED, or lamp, to operate to indicate the source of the alarm and an alarm buzzer to sound. Each alarm shall be classified as priority 1 (requiring urgent attention) or priority 2 (not requiring urgent attention). The alarm panel shall extend the priority 1 or 2 alarms to the master alarm panel.

One bay alarm panel shall be designated as the master alarm panel (usually located on MER1) and shall accept the priority 1 or 2 alarms from the bay alarm panel which shall cause a LED, or lamp, to light to indicate the bayline generating the alarm. The master alarm panel shall also extend a communication alarm to the power station alarm panel on receipt of a priority 1 or 2 alarms.

On alarm condition, all communications apparatus supplied under this Contract shall provide a visual display of the fault on the apparatus front panel, as well as an external general alarm output via a voltage free contact.

This contact shall extend an earth for connection to the bay alarm panel but if other alarm outputs are proposed by the Contractor, they shall be specified for approval by the Employer.

The communication room temperature shall be monitored and an alarm shall be extended to the communication room master alarm panel if the temperature moves outside a fixed temperature range or if the air conditioners malfunction.

As well as the above earth alarms, the master alarm panel shall be able to monitor 48V DC inputs and raise an alarm if the voltage drops below a fixed reference level.

6.7.2.5 Grounding for telecommunication equipment

Use common grounding of substation and machine room to ground telecommunication systems at the Site. Each grounding (surge voltage, protection, task) is connected to system by separate ground wire. The value of ground resistance base on TCN 168-141:1999 standard.

6.7.2.6 Lightning resistance

Lightning protection for telecommunication equipment conforms to TCN 68-135:2001 standard, including:

Lightning resistance spread on AC power supply line.

Lightning resistance spread on information cable line.

Equipment lightning resistance; combine wire connection board of MDF to resist the lightning that spread on information cable.


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6.7.3 SDH Telecommunication System

6.7.3.1 Overview

This system will be furnished for the purposes of providing communication channels for SCADA and hotline from NLDC (A0) and NRLDC (A1) to power plant and channels for protection relay between the Project and relevant power plant and substations of the Employer.

The configuration of the optical fibre communications system is shown on the structure of optical transmission network in Volume 9 Drawings. Drawings of equipment connection layout 1 and equipment network connection layout 2 (outside-plant) shows the detailed connection of equipments.

The Contractor shall be completely responsible for the successful design, fabrication, testing, installation, supervision, Commissioning and after sale services of all equipment to be supplied under this Project. This document requests proposal from the Contractor for all of the hardware, software and services needed to provide a full function and fully operational communication system that shall meet the technical requirements stated hereinafter.

6.7.3.2 Optical Fibres and Accessories

(a) Purposes

To develop the maximum existing capacity of communication equipments and link to the electric utility communication system, it is necessary to install optical fibres links using of SDH/STM-4 (ADM configuration) and SDH/STM-1 (ADM configuration) equipments between Thai Binh 220kV switchyard and central control building, as well as between the Project and relevant power plants and substations.

These links use synchronous optical equipments, multiplexer with optical interfaces. These links will support telephone communication, PABX networking, data transmission and computer networks, tele-protection signal transmission.

(b) Non-metallic fibre optical cable (NMOC)

Cable Construction:

The supplied cable shall be a non-metallic type for direct ground burial and cabling in duct, single mode fibres. The core and the cladding shall consist of glass, which is predominantly silica (SiO2). Coating usually made from one or more plastic materials or composition shall be provided to protect the fibre during manufacture, handing and use.

Around a dielectric central member will be made of fibre reinforced plastic, buffer tubes and filling compounds are stranded to form the core of the cable. The central member, which perform mainly as anti buckling element shall be coated with a PE-jacket, if this is required to obtain the correct stranding radius. A dielectric core wrap or binder is applied around the stranded loose tube core.

Water blocking material shall be made of either super-absorbent polymer yarns/types or filling compound.


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The cable must be of stranded loose buffer construction where fibres are contained in a series of tubes (usually 6). The inner diameter of the tube must be greater the diameter of the fibre bundle contained in the tube. The ratio of inner diameter of the tube and the size of the fibre bundle must be large enough so that the fibre does not adhere to the inner surface of the tube. At the same time, the fibres must have enough free space inside the tube to provide the required level of the mechanical and environmental performance.

The buffer tube shall be filled with a non-hygroscopic, non-fungus-nutritive, electrically nonconductive, homogenous gel. The gel shall be free from dirt and foreign matter. The gel shall be readily removable with conventional non-toxic solvents; the fibre shall not adhere to the inside of buffer tube. Each buffer tube in the finished cable is distinguishable from the others by means of colour coding.

The jacket shall not promote the growth of fungus and shall be free of holes, splits and blisters. The cable jacket shall contain not metal elements and shall be of a consistent thickness.

Non-metallic Optical fibre technical characteristics:

Standards: The relevant parts of IEC 60793

Optical fibre: single mode

Number of fibres: 24

Working wavelength: 1550 nm

Diameter fibre mode field:

Wavelength: 1550nm

Range of nominal values: (8.6 - 9.5) m

Tolerance: 0.7 m

Core concentricity error: 0.8 m

Cladding noncircularity: 2 %

Cladding diameter: 125 m 1 m

Max attenuation index

at 1310 nm: 0.34 dB / km

at 1550 nm: 0.22 dB / km

Transmitted signal dispersion

at 1310 nm: 3.5 ps/nm.km

at 1550 nm: 18 ps/nm.km

Cut-off wavelength: 1260 nm

Operating temperature range: -20°C +80°C

Mechanical properties:

Type: non-metallic for duct installation and direct burial


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Sheath: polyethylene

Type of sheath: anti-rodent and termite

Maximum tension strength: 2700N

Bending radius

During installation: 20 times outer diameter

Post installation: 10 times outer diameter

Working temperature: -5°C +70°C

Relative humidity: (0 100)% non-condensing

(c) Optical Fibres joint box for line towers

The joint box shall be designed for connecting and branching OPGW cables at the tee off-line and between OPGW and FO (non-metallic fibre optical cable) at the terminal towers, wherever practical. The OPGW shall be brought down the towers on the inside of the tower legs to a joint box located approximately (45) meters above ground.

The Contractor shall supply the joint boxes, and associated mounting hardware, to provide a protected environment for joining the OPGW to OPGW with attachment of the OPGW to the tower and OPGW to FO. The joint boxes shall suitable for mounting on the lattice steel towers. The joint boxes shall be fully protected against corrosion and be dust and water proofed. The joint box shall be designed for connection of the two OPGW conductors. Each joint box shall provide access from one side only for both installation and maintenance. Access to the joint boxes shall be a single lockable hinged door. Each joint box assembly shall include all mounting hardware optical fibre splice bits cable seals and other accessories for a permanent joint.

(d) Fibre optical cable terminal box with ODF

The Contractor shall supply terminal joint boxes with ODFs and associated mounting hardware to provide a protected environment for the jointing and terminating of the fibre optical cable.

Each joint box with ODF shall be fully protected against corrosion and dust.

Each joint box with ODF shall be included all mounting hardware, optical fibre splice tray, pigtail, connectors, fusion point protector, cable seals and other accessories for a permanent termination and distribution.

6.7.3.3 Equipment

a) Specific requirement for STM-4 equipment at Thai Binh 220kV Switchyard

- Configuration: ADM 1+1

- Optical STM-4 Interface L-4.2 06 ports

- Optical STM-4 Interface S-4.2 04 ports

- Optical STM-1 Interface L-1.2 04 ports


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- Optical STM-1 Interface S-1.2 02 ports

- Optical STM-1 Interface I-1 02 ports

- Electrical E1/120Ω PDH interface (2Mbps) 63 ports

- Fast Ethernet 10/100BaseT interface 08 ports

b) Specific requirement for STM-1 equipment at the Site central control building

- Configuration: SDXC

- Optical STM-1 interface L-1.2 24 ports

- Optical STM-1 interface S-1.2 02 ports

- Optical STM-1 interface I-1 02 ports

- Electrical E1/120Ω PDH interface (2Mbps) 42 ports

- Fast Ethernet 10/100BaseT interface 08 ports

c) Optical attenuator

For the achievement of suitable signal strength at the receiving ends of the optical fibres, there will be additional equipment to avoid overload. This equipment will be installed in the SDH system at the Site.

The Contractor shall be responsible for investigation, design, installation, testing and Commissioning of the optical attenuator at the Site, compatible with the Employer’s equipment.

6.7.3.4 PCM Multiplexer

- Configuration: drop-insert

- 64Kbps/G703.1 16 ports

- 4W E&M, G714 12 ports

- 2W remote subscriber (exchange side), Q552 08 ports

- 2W remote subscriber (subscriber side), Q552 08 ports

- 2W hotline, Q552 02 ports

- Data channel ITU-T V24/RS-232C/1200bps 04 ports

6.7.3.5 Teleprotection

- Standard: IEC-60834-1; IEC-60870-2; IEC 60793

- Function: transmit line distance protection signal over fibre optical.

- Number of commands: 3

- Security/dependability: better than IEC 60834-1

- Digital interfaces: ITU-T recommendations G703.6/2.048Mbps

- Respond time: 10ms


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- Protection mechanism: 1+1

- Power supply: 48 or 220V DC (30%, +25%)

- Maximum consumption: 15W

- Operating temperature: 100°C to 550°C

- Operating relative humidity at 400°C : 95%

- Storage temperature 250°C to 700°C

- Storage relative humidity at 230°C : 100% without condensation

- Insulation-EMC: IEC 60384-1 and IEC 61000-4-2

6.7.3.6 Rack 19” Type

Standard: ETSI

Protection class: IP20 (minimum)

Rack shall be indoors, freestanding with door and lock for accommodating equipment with dimension of standard structure 19”. Hinged frame for communication equipment mounting with insect screens and provision for cable entry from bottom. The rack can be installed on the floor, against a wall, side-by-side or back-to-back.

Rack shall have DIN bars, clamps, connection cable and fittings.

Colour: RAL

6.7.3.7 DDF/MDF Cubicle

Standard: ETSI

Protection class: IP20 (minimum)

Colour: RAL

Cubicle shall be indoor installation, freestanding with hinged front door and lock for mounting DDF and MDF with insect screens and provision for cable entry and exit from bottom and top. The rack can be stand-alone mounting.

Rack shall have bars, clamps, 2Mbps and subscriber terminal blocks, connection cable and associated fittings.

6.7.3.8 Modem

(a) Modem for transmitting SCADA/EMS signals to A0

- Transmission: asynchronous

- Modem line speeds: 14400; 9600; 4800; 2400; 1200; 300bps

- DTE rate: 57.6; 38.4; 19.2kbps

- Standards: V.32bis, V.32,V.22bis,V.22, Bell 212A,Bell 103

- Dial up: Supported

- 2 & 4-Wire leased line: ready


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- Compatibility: Hayes ª extended AT command set

- Error correction / data compression: MNP 2, 4, 5 & 10, V.42, V.42bis

- Power Supply: 48V DC

- Case size: rack modem 5.25’’

- Digital port: connectable with the back plane connections.

- Analog port: connectable with the back plane connections.

- Surge protection (power line): 8kV (exceeds IEC 61000-4-4)

- Surge protection (analog line): 3.75kVac

- Compatible with the existing system at NLDC (A0)

(b) Modem for transmitting SCADA/EMS’s signals to A1

- Transmission: asynchronous, full/half duplex or simplex

- Interface 1: EIA RS-232-C/CCITT V.24/V.28, 9-pin D-sub female or 9-pin detachable screw block

- Interface 2: EIA RS-422/RS-485/CCITT V.11 detachable 9-pin screw block

- Interface 3: CCITT V.23 2- or 4- wire, 4 pin detachable screw block

- Transmission rate: up to 1200bit/s

- Overvoltage protection:

- Mains: breakdown voltage 440V at 230V AC and 220V at 115V AC

- Line: zener diodes, breakdown voltage 68V, discharge 600W for 1ms, gas tubes 300V

- Power supply: 230V AC +15% -10%, option 115V AC

- Power consumption: <2W

- Compatible with the existing system at NRLDC (A1)

6.7.3.9 Power Supply

Two batteries 48V- 200Ah, 02 AC-220V/DC-48V/50A battery charger cubicles and two 230VAC/16A power surge voltage protectors at the Site central control building and 220kV switchyard.

Main source: AC from AC-230V/DC-48V/50A battery charger cubicle.

Standby source: From 48V-200Ah battery.

(a) Battery Charger Cubicle

Function:

- Charges in to the battery in boost mode and float mode

- Provides power source at 48VDC to communication equipment.

Mechanical Properties


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- AC/DC Power source and its component shall be placed in metal cabinet, which will be as compact as possible. It shall be equipped with voltmeter, ampere-meter and input-output breaker

- The maximum height of cabinet shall be less than 2200mm

- Power supply shall have high efficiency and long lifetime

- Rise in temperature of rectifier shall not more than 650°C in normal operating condition.

Electrical characteristics

- Input voltage: 230V AC 10%, 50Hz

- Output voltage: 48V DC 15%

- Nominal output current: 50A

- Lightning surge resistance: 10kV

- Insulation resistance: earth to AC input 5MΩ

- Withstand voltage: earth to AC input: 200V per minute

- PC interface: RS-232

- 230VAC/48V DC power sources should be regulated in equalizing mode and supply of 48V DC at nominal load from 10% to 100%.

- In addition to disconnecting the load at the end of battery discharge as standard function, load shall be re-connected automatically when 230V AC power is restored.

- Built-in protective circuit shall be provided to prevent overload, surge power short circuit condition.

Charger will have an automatic battery test facility, display to indicate the operating parameters and alarm when load voltage drops over 10% nominal voltage, including:

- High voltage

- Module failure

- Low battery

- Main failure.

Will have meter and control mode to indicate the following features

- Output voltage

- Load voltage.

Total metering and indicating error less than 1% of meter scale.

Installation materials, power cable, signal line, earth wire, connectors and control software shall be also provided by Contractor.

Environmental Conditions: TCN 68-149.


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(b) Battery

Type: free-maintenance, sealed lead acid environmental friendly

Rated voltage: 48V

Rated tank voltage: 12V

Capacity: 200Ah

Operating temperature: (5 - 45)°C

Float charge: 2.23V/cell

High rate charge: 2.65V/cell

Average self-discharge level not more than 0.5% in 24 hours

Including connectors and clamps for interconnection of battery tanks.

(c) Power Surge Voltage Protector

Function will be as follow:

- Shunt surge diverter

- Shunt reduction filters

Rated voltage: 230V AC 15%

Operating voltage (max): 275V AC

Operating current: 16A

Indication: time of protection discharge

Guarantee (minimum): 5 years

Dimension: shall be module type for easy installation and maintenance

Protection level: II

Environmental conditions: TCN 68-149

All equipment must comply with relevant technical regulations and standards and must be approved by the Employer.

6.7.4 Private Automatic Branch Exchange (PABX) System

6.7.4.1 Scope of Supply

The Contractor shall provide, install, test and commission digital main PABX and back-up PABX located in the central control building telecommunications room which extends to other buildings and plant areas under approval of the Employer.

6.7.4.2 Particular Requirements of Main PABX

All-in exchange include: cabin, power supply, lightning support, MDF shelf, connector, attached accessory, etc.:

Minimum capacity: ≥16


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Analog subscriber: ≥500

Digital subscriber: ≥18

E1/2Mbps trunk line: ≥16

4W E&M trunk line: ≥16

CO trunk line: ≥8

Numbering capability: ≥07

Ethernet port for network management: ≥02

6.7.4.3 Console Table

Two console tables shall be equipped for dispatching duty table of the Project.

Console table’s functions:

To be able to connect to hotline channels (hot-line)

Display on LCD about busy or idle statuses of hotline channels

It shall be possible for the shift operator to selectively answer incoming calls to the console table. The other calls will remain in the call announcement queue until they are answered.

Connecting console table to hotline channels:

Digital subscriber ports of the exchange are connected to MDF. One of that is connected to console table by 5x2x0.5 cable which is zinc-covered cable to guard against interference. To be able to connect to hotline channels (hot-line).

02 Hot-line channels transfer to A0, A1 are connected with CO ports on the MDF rack.

The hotline channels which will be used to communicate with the dispatch centres from the plant are connected to the exchange’s subscribers and can be programmed into speed dial.

6.7.4.4 Subscriber Network

The PABX switchboard subscriber network come out from main distribution frame (MDF rack) located at the communication room in the central control building.

In order to protect the switchboard gates against the lightning through subscriber routes, the subscriber lightning protection units shall be provided with the connection paddings on MDF.

6.7.4.5 Back-up PABX

The backup telephone private branch exchange (back-up PABX) provides an independent telephone system for managers’ offices and operating staff offices. The backup telephone private branch exchange (back-up PABX) will provide for up to 100 extensions capacity. Major operation positions and working rooms provided for persons who directly involves in the power plant operation shall be


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supplied with at least two hand sets of separate connection links (one for the main PABX and the other for the back-up).

The back-up PABX will be accommodated in the central control building and have a separate DC supply. It will provide voice communications within the power station as well as to the external public network of Vietnam (PTN).

The back-up handsets will be provided for a simple dialling code or programmed push buttons. Location of these handsets is to be advised by the Employer.

6.7.4.6 Telephones (Main and Back-up)

Standard telephones shall have at least the following features capabilities:

Approved for connection to the public telephone network;

Capable of pulse or tone dialling with 0-9, * and # keys;

A 100 millisecond loop-break PABX recall key;

Be capable of storing at least 10 x 20 digit telephone numbers;

Stored telephone numbers are to be retained when the telephone is removed from its socket.

Be capable of being wall mounted; and switchyard telephones shall be of weatherproof construction.

In areas where the noise level is high, handsets shall be located in acoustic booths or hoods which shall have a beacon mounted immediately on top which shall flash when the extension number is dialled and a horn which shall sound.

Acoustic booths (or hoods) shall be lined with absorbing acoustic material and be complete with a writing shelf. They shall be designed to reduce the background speech interference level to 60 dB. Telephone boxes sound-proof telephone boxes shall be provided on each of the three floor levels in the boiler/turbine areas. A large flashing blue light shall be mounted on the outside of the box to indicate that the phone is ringing.

6.7.4.7 Telephones Cable

The supply and installation of telephone cables is covered under Volume 2.

6.7.4.8 Intermediate Distribution Frames (IDFs) and Final Distribution Points (FDPs)

In locations other than communications room IDFs and FDPs shall consist of 2 verticals (of various sizes) consisting of 10 pair KRONE disconnection modules. They shall be mounted in a communication cabinet or contained in a wall mountable plastic box and be accompanied by a suitable termination record book.

6.7.4.9 Telephones Sockets

Telephone sockets shall be provided at each required terminal equipment location and shall consist of a flush mounted RJ45 socket and matching faceplate with suitable icon indicating its function.


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6.7.4.10 Location of Telephones

Extension telephones from the main PABX shall be provided generally as follows:

Plant control room 2

Managers offices 1 each

General offices 1 per 10 m2

Switch/control rooms 2 each

Equipment/Plant rooms 1 each

Turbine floor 4 per floor level

Gate house 1

Storage areas 1 per 100 m2

Workshops 1 per 50 m2

Chemical laboratory 2

Library, medical room, shop, reception 1 each

VIP and staff dining rooms 1 each

Extension telephones from the back-up exchange shall be provided as follows:

Plant control room 2

Station manager’s office 1

Shift manager’s office 1

Guard house 1

Coal handling control room 2

Other manager’s offices 1 each

Final quantities and locations of phones will be determined during the design phase.

6.7.5 Public Address System (PA System)

6.7.5.1 Scope of Supply

The public address system shall consist of but not be limited to the following:

Pre-amplifier and central processing unit

End-amplifier

Loudspeaker

Paging phone

Microphone


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6.7.5.2 Technical Requirement

Pre-amplifier and central processing unit

Pre-amplifier and central processing unit shall be designed in opened module structure or compact structure.

Input voltage : 230V AC – 50Hz

Pre-amplified power : 100W

Number of microphone inputs : 4

Minimum zone : 18

End-amplifier

Input voltage : 230V AC – 50Hz

Amplified power : 200W

Minimum output : 5

End-amplifiers shall be located in protective cubicle with high protection level (IP54), waterproof and fire fighting cover. They shall be mounted on the wall.

Loudspeaker

Loudspeakers using indoor shall be high wet condition withstand type

Input voltage: 100,70 V

Power: 10W, 20W, 30W

Sound pressure level: :110 dB

Resistance: 8

Frequency range: 280 - 12500 Hz

Protection class: IP55

Paging phone

Paging telephones shall be specialized, high waterproof level, wet condition withstand level with good noise filtering ability. They shall be equipped with connection box for loudspeakers.

Mounting type: Suspended type

Minimum protection class: IP54

Microphone

Type: Desktop, handy

Frequency range: 280 – 12500 Hz

Sensitive level: -70dB

Minimum protection class: IP54


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6.7.5.3 Location of Loudspeakers

Loudspeaker system is located around the Site and in the specific locations.

At central control building

Switchyard area

Administration area

Water treatment area

Mechanical workshop and material storage area

Security gate.

Outside areas of plant: The outside of plant such as: oil pump station, water return pump station and coal & oil unloading jetty: provided loudspeaker is type of 10W and 20W at stipulate locations. The announcement sound level shall be at least 20dB(a) above surrounding base sound level.

6.7.6 Supervision Camera System

This function and location of this equipment is covered by Volume 7.

The Contractor will have his design for supervision camera system including the number of cameras at appropriate locations, mode of connection of equipment and submit to the Employer for approval.

6.7.7 UHF Systems

6.7.7.1 Two-Way Radio System

a) General

The UHF 2way radio system shall allow communication from the control rooms to the operating and maintenance staff in the field. The base units shall be located in each PCR, coal handling control room, and guard house.

The coverage area shall include at least the remote location of the cooling water intake house.

If applicable at least nine (9) individual communication channels shall be selectable.

The base units shall have a battery backup power supply. The battery charger shall be connected to the safe 230VAC (Diesel powered).

The standby operation time of the hand held units shall be at least eight (8) hours.

The battery charger and the batteries shall include a smart charging scheme to avoid premature capacity degradation.

The UHF radio system shall be delivered, installed, and commissioned as ”ready for use” and be available before commencing the first unit’s performance test.

The Contractor shall be responsible for obtaining the necessary operation licences.


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The Contractor will have his design for UHF system and submit to the Employer for approval.

b) Scope of Supply

Four (4) base stations, complete with connected antenna, microphone, and loud speaker;

36 multi channel hand held units, including carrying gear;

Twelve (12) external microphones for the mobile units;

Twelve (12) battery charger station (on 230VAC), or four (4) equivalent fixed multi slots charging stations for the mobile units (batteries);

Necessary power supplies, fix mounted antennas, cables, and all fixing material;

Six (6) spare battery packs for hand held units;

Documentation.

c) Technical Details

Working mode: half-duplex

Operating frequency: (403 470) MHz

Central antenna: multi-directional 2 x 5/8 (stacked), installed on antenna pile.

Feeder cable of antenna: type 10D-FB with surge voltage protector for feeder

Electricity charger: use converter battery charger cabinet 230V AC/13,8V DC

45W UHF radio machine has interface port with the PABX switchboard through 2-wired subscriber cable

For more technical details refer to Volume 2, General Technical Provisions.

6.7.7.2 Pager System

A pager system shall be supplied to enable alarming operators, engineers, and administrative personnel on special occasions even when the public mobile phone system is unavailable. The power supply shall be battery backed and charged from the safe 230VAC (Diesel powered)

The covering range shall include at least the nearby city of Thai Binh and its vicinity.

The operation frequency shall be preferable in the 900MHy band.

The personnel pager devices shall have a one-way operation mode, capable of displaying numeric and text characters.


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A paging request shall be possible at least from every control room, preferable form each and every in-house telephone set (PABX).

The pager system shall comprise of, but not limited to:

Base station, including power supply (safe 230VAC), and HF transmitting devices;

Three (3) operation stations, if applicable;

Fifty (50) personnel units, including their battery charger;

Necessary repeater stations;

Documentation;

The pager system shall be delivered, installed, and commissioned as ”ready for use” and available before commencing the first unit’s performance test.

The Contractor shall be responsible for obtaining the necessary operation licences.

The Contractor will have his design for pager system and submit to the Employer for approval.

6.7.8 Local Area Network

Scope of Supply

The Contractor shall provide, install, test and commission the LAN located in the central control building and other buildings and plant areas under approval of the Employer. This network shall consist of but not be limited to the following:

Server

Router

Switch 24 ports

Modem

PCs

ODF

UTP/CAT-6 and FO cable

RJ-45 connector and accessories

Technical data shall be as per the requirements of Volume 7.

The Contractor will have his design for LAN and submit to the Employer for approval.


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6.7.9 Installation and Cabling

6.7.9.1 Power Cables

The total voltage drop from the power supply to the apparatus shall be less than 1V. Power supply cabling shall be of sufficient size to produce less than 0.5V drop between the power supply and the distribution panel in each MER, and 0.5V drop between the distribution panel and the apparatus.

6.7.9.2 Miscellaneous Equipment Racks

The MER’s circuit breaker and fuse panels shall be installed as appropriate. Circuit breaker and fuse panels shall be connected to the power supply using cables that conform to Clause 6.7.9. (1) above.

Alarm panels shall be connected to a master alarm panel according to the suppliers’ instructions. The master alarm panel alarm extension relay shall be connected to the power station alarm system.

6.7.9.3 Other Equipment

The Contractor shall:

(a) Erect all equipment racks and/or cubicles to be supplied under this Contract.

(b) Connect all equipment racks and/or cubicles to the communication room earthing system.

(c) Connect all equipment racks and/or cubicles to 48V circuit breaker or fuse panels as appropriate.

(d) Connect all equipment racks and/or cubicles to the appropriate alarm panel.

(e) Interwire all multiplex equipment to the MDF.

(f) Jumper MDF to services and IDFs and telephone extensions.

For equipment being supplied under the Contract, items (a) to (e) above will be carried out by that Contractor.

The Contractor shall carry out such tests as are necessary to prove that the equipment installed is performing according to the manufacturer's specifications.

After all cables have been installed and the equipment commissioned, the cable entries to the communication room shall be sealed against vermin entry. The sealant used for the cable entries shall be removable to allow for the addition, or removal, of cables at a future date without impairing the effectiveness of the vermin proofing.

The vermin proofing method adopted shall be subject to approval by the Employer.


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6.8 TEST AND INSPECTION

6.8.1 Application

The following test and inspection clauses are applicable to the electrical systems. They cover tests in the works, tests on Site and Commissioning tests. In addition to these requirements reference must be made to Volume 2 which details test and inspection on electrical Plant components.

6.8.2 Generator

6.8.2.1 Test and Inspection at Workshop

(1) General

Where no specific test is specified then the various items of Plant, materials and equipment shall be tested in accordance with the applicable standard, acceptable to the Employer. Where no appropriate standard is available, tests shall be carried out in accordance with the maker's standard practice, subject to the prior approval of the Employer. In all cases, Works tests shall include electrical, mechanical and hydraulic tests in addition to any tests called for by the Employer to ensure that the Plant being supplied fulfils the requirements of the Specification.

If considered necessary by the Employer, any multi-part assemblies shall be fully erected in the works prior to packing and dispatch to the Site.

(2) Tests on Materials

Representative samples of plates, bars and pipes, etc., which form components of the Plant shall be tested to the relevant approved standard or code at the request of the Employer.

All test pieces shall be prepared and supplied by the Contractor at his own cost. If any test piece fails to comply with the requirements of the Specification for the material in question, the Employer may reject the whole batch of material represented by that test piece.

All important forgings are to be examined jointly at the maker's works by the Employer, together with representatives of the manufacturer during forging and heat treatment.

The test shall be carried out on the following but be not limited to:

(3) Generator rotors

The generator shall be subjected to tests to prove compliance with IEC 60034 to prove that it has been manufactured correctly and for the determination of characteristics.

(4) High Voltage Tests

All parts of the generator shall be subjected to a high voltage test in accordance with the requirements of IEC 60034-1.


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(5) Temperature Rise

Tests shall be carried out to prove that the temperature rise of the various parts of the generator are within the limits required by IEC 60034-1.

Temperature rise tests shall be carried out also at Site in accordance with performance testing criteria to prove the guarantee of performance.

(6) Insulation Tests

(a) The insulation resistance of the stator and rotor windings shall be measured with the windings cold and at the completion of the temperature rise tests.

(b) The polarization index of each stator phase winding and of the whole winding shall be measured with the windings cold and hot.

(c) Repetitive surge tests shall be carried out on the rotor winding to confirm the integrity of interturn insulation.

(d) The insulation of stator bars and coils shall be tested in accordance with IEC 60894.

(e) Each phase of the stator windings shall be tested to determine its capacitance (in nanofarads) to earth and dielectric loss angle (in milliradians) in 0.2 Un steps from zero to rated phase-phase voltage, both raising voltage and lowering voltage. Each test will involve energizing one phase winding with the other phase windings earthed.

The same tests shall also be carried out with the three phase windings connected together to measure combined values.

The report of test results shall include a description of the testing technique used, the Plant conditions (including gas and water coolant arrangements and temperatures) and the test equipment used.

The Contractor shall submit the proposed test procedure for approval by the Employer.

(f) Each phase of the stator windings shall be tested to determine the levels of partial discharge (in picocoulombs) of insulation in 0.2 Un steps from zero to rated phase-phase voltage both raising and lowering voltage. Each test will involve energizing one phase winding with the other phase windings earthed.

The report of test results shall include a description of the testing technique used, the Plant conditions (including gas and water coolant arrangements and temperatures) and the test equipment used.

The Contractor shall submit the proposed test procedure for approval by the Employer.

(7) Tests to Determine Generator Parameters

(a) The Contractor shall determine the following parameters for each generator. The Contractor shall nominate, for approval by the Employer, the tests to be performed to determine the parameters with reference to IEC 60034-4.


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Where a nominated test is not in accordance with IEC 60034-4, the Contractor shall justify its use.

The Contractor shall nominate expected values of the generator parameters in Technical Schedules.

(b) Saturation Curves, Segregated Losses and Efficiency

Open-circuit and short-circuit tests shall be carried out to determine:

Open-circuit saturation curve and air gap line

Short-circuit saturation curve

Zero power factor overexcited saturation curve for rated armature current

Segregated losses (core loss; stray-load loss; friction and windage loss; armature and field losses)

Efficiency

(8) Waveform Deviation

The waveform of the generated voltage shall be measured and analyzed in accordance with IEC 60034-1.

(9) Shaft Current

Tests shall be carried out with the generator at rated speed and excited to rated voltage on open circuit to prove that circulating shaft currents are prevented by the bearing insulation and shaft earthing provided.

6.8.2.2 Test and Inspection at Site

(1) General

All Plant and Equipment shall pass such tests at Site as are required by the Employer to prove compliance with the Specification independently of any tests which may have already been carried out at the manufacturer's works.

The tests at Site shall include, but not necessarily be limited to, those specified in this section.

In particular all functional and pressure tests on fully assembled and complete items of Plant which have not been carried out at the manufacturer's works, shall be carried out at Site.

The commissioning tests shall be carried out in accordance with the requirements of Volume 2.

(2) Turbine/Generator

(a) No load Plant Commissioning test shall include the following:

Test of intervention of the stand-by oil pump automatically

Measurement of the thermal expansion of the casings


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Verification of the speed control and safety trips operated locally and remotely

Tests on all safety devices

Tests on trip valves and alarms

Measurement of vibration (generator not excited)

Checking of speed measuring instruments

(b) Load test shall include:

Adequacy of gland steam sealing system

Temperature of bearings

Vibration reading at various loads (generator excited and turbine/generator synchronized.)

Synchronizing tests

Bearing inspection after 5 days operation at RO

Automatic changeover of all stand-by equipment

Verification of the start-up time to attain the RO from cold, warm and hot conditions

Tripping of the unit at loads 30%, 50%, 75% and 100% RO.

No malfunction or endangering of the equipment shall take place and all controls shall operate safely.

Capability of House Load Operation.

After having the unit load at RO, the turbine/generator shall be disconnected from the network and it will remain in operation at "house load" feeding only the unit auxiliary service.

Rapid load reduction when the load is above 50% RO, by manually tripping of one circulating water pump (CWP) or one Boiler Feed Pump (BFP) without the intervention of the stand-by pump.

Any other tests required by the Employer to check the specified conditions of the plant.

6.8.3 Excitation System

6.8.3.1 Test and Inspection at workshop

The Contractor shall submit a list of proposed excitation system tests for approval by the Employer it will include but not necessarily be limited to those items listed below.

(1) Thyristor Bridge

Tests shall be carried out on the thyristor bridge as required by IEC 60134.


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With reference to the temperature rise test, the temperature rise must remain within limits for a duty cycle no less than that specified in Volume 2.

(2) Excitation Transformer

The Contractor shall carry out temperature rise tests at the manufacturer’s works, using a higher than rated current to prove that in-service rated temperature rises will not be exceeded. The test current shall take into account the extra losses due to harmonics and shall be determined by reference to IEC 60354.

(3) Complete Excitation System

The tests listed in the following clauses, except for Clauses (a) and (b), shall be carried out on both excitation systems. The tests listed in Clauses (a) and (b) need only be carried out on the first manufactured system.

(a) A transfer function test shall be carried out on the excitation system for the determination of all time constants, gains, input/output limits and frequency response curves. The block diagram Drawing T-showing the transfer functions of the excitation system shall be amended from the results of these test and included in the test report.

(b) An excitation system nominal response test shall be carried out to determine the excitation system nominal response VE. The voltage error step to be used in the test is 10% of rated voltage. Where the test is not in accordance with IEC 60034-6, the Contractor shall justify its use.

(c) Checks shall be carried out on the operational features of the automatic excitation regulator; including automatic changeover from one controller to another; and to manual operation of limiters; follow-up controls and alarms.

(d) All other tests as necessary shall be carried out to prove compliance of the excitation system with the specified requirements.

6.8.3.2 Test and Inspection at Site

(1) Tests shall be carried out to prove that the stability and damping of the automatic excitation regulator (AVR) complies with the specified requirements. Tests with the stabilizing signals connected and disconnected shall be carried out to demonstrate the effect of all stabilizing signals used in the AVR. The tests shall be carried out with the generator operating on open circuit and rated voltage, and also with the generator on load.

(2) With the generator on-load and feeding into the system, the operation of the AVR over and under excitation limiter, and limiter failure detectors shall be proven.

(3) With the generator on open circuit and under AVR control, the generator terminal voltage shall be measured at speeds corresponding to 47, 50 and 52 Hz without changing the voltage set point.

(4) The voltage drop compensation shall be proved effective. the Employer will arrange for variations in system voltage to permit reasonable reactive load changes to be made on the generator. The Contractor will make electrical measurements to confirm the degree of compensation.


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(5) The control system for coordinating reactive power loading of the generator shall be proved to be able to carry out its function by in-service test. the Employer will arrange for variations in reactive power demand on the generators for this test.

(6) With the generator on open circuit and under AVR control, changeover of the AVR from one control function to another (i.e. auto-auto, auto-manual) shall be proven for each fault condition.

(7) All necessary tests shall be carried out to check the excitation system transfer function block diagram.

6.8.4 AC Auxiliary System

6.8.4.1 Unit Load Power Consumption

The auxiliary power system shall be set up with the station to unit 6.6kV and 400V links broken - i.e. such that unit auxiliaries are being supplied from the unit auxiliary transformer (machine voltage to 6.6kV) and station auxiliaries are being supplied from the 220/6.6kV station transformer. The total unit auxiliary kW load shall be measured at the unit auxiliaries 6.6kV switchboard incoming power supply to a level of accuracy equal to or less than 1.0% error. To achieve this, the necessary incoming circuit metering current transformers shall have accuracy of class 0.1 and the switchboard busbar voltage transformer class 0.2.

The generating set shall be stabilized and then run continuously at 100% RO for 2 hours and the power consumption figure shall be taken as the average across the period. The Contractor shall submit the following correction curves or formulae and apply for the tests:

(a) ID fan consumption related to draught at the point of connection to the stack inlet.

(b) CW pump consumption related to variations in river level.

(c) Other(s) - to be recommended by the Contractor.

6.8.4.2 Transformers

(1) Test and Inspection at Manufacturer’s Works

(a) The following tests shall be conducted on each transformer (except that tests (13), (18) and (22) are only applicable to oil filled).

1. DC insulation resistance (1 minute readings taken for 10 minutes)

2. Winding Dielectric Dissipation Factor (DDF) at 2.5kV interwinding DDF at 2.5kV

3. Winding resistance on all taps and all windings

4. No load loss at 100%, 105% and 110% voltage

5. Load loss at extreme taps and principal tap

6. Impedance at extreme taps and principal tap

7. Zero sequence impedance


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8. Power frequency withstand tests

9. Induced voltage tests

10. Partial discharge tests

11. Impulse tests on minimum turns tap

12. Temperature rise test on each rating for a minimum period of 12 hours.

13. Thermovision monitoring of tank temperatures during the test shall be carried out. Type test only for transformers rated 3 MVA and below.

14. Harmonic components at no load (also see 5. above)

15. Tank vacuum test to prove tank, conservator and cooling system can satisfactorily withstand a full vacuum

16. Jacking point deflection test

17. Ratio and phase relationship

18. Insulation oil tests

19. Control circuitry testing

20. WTI, RTD, OTI and fibre optic calibrations

21. Sound level test (type only)

22. Oil overpressure test

(b) On completion of the component parts, the transformer shall be completely erected at the manufacturer’s works to permit a final inspection to be made of the mechanical and electrical assembly and for overall testing.

(c) For all tests during which a transformer is excited either at normal or higher frequency all thermal and gas sensing devices shall be connected so that any abnormality may be detected.

(d) Dissolved gas analysis of oil shall be carried out prior to and after the power frequency test, induced, partial discharge and the temperature rise test

(e) Partial discharge tests shall be performed in turn upon each HV terminal. The method of partial discharge measurement shall be one of the internationally accepted methods employed to determine individual impulse magnitudes in pC (apparent discharges as measured at the terminals), in accordance with the relevant IEC recommendations.

(f) The following partial discharge measurement shall be recorded during voltage raising:

Partial discharge level at 120% of rated voltage

Partial discharge level at 150% of rated voltage

At minimum induced overvoltage

Partial discharge level upon returning to 150% of rated voltage


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Partial discharge level upon returning to 120% of rated voltage

The test duration for recording the partial discharge measurements shall be half (½) an hour for each measurement level.

(g) The transformer will have failed the partial discharge test if the levels recorded appreciably exceed:

60 pC at 120% of rated voltage;

300 pC at 150% of rated voltage.

All instruments to be used, in connection with these tests shall be calibrated before and after tests. The Contractor is requested to provide for each instrument used during these tests calibration certificates of independent test institute.

(2) Test and Inspection at Site

Following installation in its final position and full connection of controls, each transformer shall be subject to the following tests:

(a) Functional test of controls.

(b) DC insulation resistance at one minute intervals for 10 minutes.

(c) Winding DDF at 2.5 kV.

(d) Interwinding DDF at 2.5 kV.

(e) Winding resistance on all taps on all windings.

(f) Ratio and phase relationships.

(g) Insulation oil test for dielectric strength and moisture content.

(h) WTI, RTD, OTI and fibre optic calibrations.

(i) Dissolved gas in oil analysis.

(j) Thermovision of connections following placement on load.

6.8.4.3 Switchgear


(a) Type, sample and routine tests should be conducted and certificated in accordance with all of the relevant provisions of the standards listed in Volume 2.

(b) HV switchgear shall be type tested for arcing fault containment and judged against Appendix AA, criteria 2 and 4 of IEC 62271-200.

(c) Low voltage CFS unit compartments shall be type tested to IEC 61439-1 for arcing fault containment where the energy level available to the terminals exceeds 1,000,000 A2 seconds.

(d) HV power frequency test as per IEC 60060 for HV testing.

(e) Complete shipping sections of switchboards shall be subject to at least the following tests before leaving the works:


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Point to point wiring checks.

Insulation resistance of switchboard and busbars.

Circuit switch operational checks.

Mechanical interlock checks.

Contact resistance checks on switch contacts and racking contacts.


Following Site assembly in final positions and the completion of connections, testing shall include at least the following:

(a) Point to point wiring checks.

(b) Switch operational checks.

(c) Mechanical racking interlock checks.

(d) Primary circuit connections and phasing checks including power cabling.

(e) Protection primary and secondary injection tests, operation, calibration and interface checks.

(f) Plant system functional checks including control, indication, alarms etc. interface.

(g) Insulation resistance measurement.

(h) Thermovision of primary circuit connections following placement on load.

6.8.4.4 Electrical Protection and Metering


(a) Protection and metering relays and equipment shall be subject to type, sample and routine tests in accordance with the relevant standards to which the equipment is constructed. Predominantly this will be IEC 60255 covering protection relays.

(b) Following assembly into shipping sections of switchboard equipment shall be subject to operational tests.


(a) Systems shall be subject to operational checks following installation of switchboards and panels in their permanent position.

(b) Protection systems shall then be subject to primary and secondary current injection tests covering full calibration and placement in service. Refer also to Volume 2.

6.8.5 Cabling, Wiring and Terminals

Refer to Volume 2.


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6.8.6 Earthing and Lightning Protection

Refer to Volume 2.

6.8.7 Miscellaneous Power and Lighting

Refer to Volume 2

Equipment shall be subject to type, sample and routine testing in accordance with the standard(s) to which it is built.

(1) Operational checks.

(2) Measurement of lighting levels in areas to be nominated by the Employer.

6.8.8 DC Auxiliary System

DC Plant components shall be type, sample and routine tested in accordance with the provisions of the relevant standards referred to in Section 6.4. In addition a discharge test to the agreed duty cycle shall be carried out on each installed battery bank.

In addition to controlling and monitoring overall discharge current and voltage, individual cell voltage shall be logged so that defective cells (if any) can be identified. The metering accuracy shall be such that the overall battery bank capacity can be declared to an accuracy of 0.5%.

6.8.9 Phase Isolated Busbars

6.8.9.1 Busbar Assemblies

Busbar Assemblies

The capacitance of the fully assembled busbar system shall be measured on Site.

Busbar Conductors

Busbar conductors shall be tested in accordance with BS 159, BS 1977 or BS 2898 as applicable.

Busbar Support Insulators

Busbar support insulators shall be tested in accordance with IEC 60168 or IEC 60137 as appropriate.

Voltage Transformers

VTs shall be tested in accordance with IEC 60186 and IEC 60044.

(1) One VT shall also be subjected to a temperature rise test when operating at rated voltage and rated current.

(2) Impulse testing in accordance with IEC 60060 Parts 1 and 2 shall be carried out as a routine test on each VT and after the impulse tests have been completed each VT shall also be high voltage tested.


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(3) The impulse and high voltage withstand tests shall be carried out with the temperature of the oil and windings as near as possible to the normal working temperature of the transformer.

(4) It shall be noted that the VTs will be used as three-phase units, and all tests, except the temperature rise test, shall be made on complete assemblies and not on separate cores.

(5) A cubicle with the VTs in the ‘in-service’ condition is to be subjected to 150 kV impulse test.


(1) CTs shall be tested in accordance with IEC 60185 and IEC 60044.

(2) A sheet metal tube, 600 mm long, shaped to represent the primary bar profile shall be arranged symmetrically and coaxially through the toroid. The tube shall be insulated from earth. A resistor representing rated burden shall be connected to the secondary terminals in series with an AC micro ammeter.

(3) A 50Hz test at 10kV rms shall be applied between the sheet metal tube and the earthed secondary winding and the current in the secondary circuit shall be measured (no current shall be passed through the primary during this test).

6.8.9.3 Distribution Type Earthing Transformers

(1) The distribution type earthing transformers shall be tested in accordance with IEC 60076 Parts 1 to 5 or if applicable IEC 60076-11 with the following modifications and addition:

(2) One transformer shall also be subjected to a temperature rise test at both the continuous and the 30 minute ratings.

6.8.9.4 Neutral Earthing Resistor Tests

(1) Type Tests

(a) An element of each resistor type shall be subjected to the rated 50Hz current for that type of element for six seconds. The temperature of any part of the element shall not exceed 305°C (allowing for a 40°C ambient). Suitable connections being as close as possible to those to be used in the actual assembly shall be connected to the element for this test. The temperature rise shall be measured by thermocouples connected to a recording instrument. The temperature shall be recorded for at least thirty seconds following the passage of the current.

(b) Prior to the above temperature rise test the DC resistance of the selected element shall be measured by passing a DC current of approximately ten amperes through the element and measuring the voltage drop so produced.

(c) The voltage shall not be measured until thermal equilibrium has been reached and the temperature of the element shall be recorded. The resistance shall be corrected to 20°C.


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(d) Following the temperature rise test above the test described in (b) above shall be repeated. The resistance when corrected to 20°C shall be within +1% of the previous value.

(2) Routine Tests

(a) The resistance of each fully assembled unit shall be measured as described in (ii) above. The resistance, corrected to 20°C, shall not differ from the nominal value by more than the stated tolerance.

(b) Measurement of resistance shall be carried out as a routine test to prove compliance with the limits specified in Clause 6.5.1.13. Using the maximum temperature determined in that clause the “hot” resistance shall be calculated and their result entered on the test certificate.

(c) With the maximum resistance between the end of the resistor bank and the earth terminal open, the bushing and resistor shall be subjected to the one minute insulation test voltage stated in Clause 6.5.1.13. The unit shall be considered to have passed this test if there is no flash-over to earth or between resistor elements for the duration of the test.

6.8.9.5 Earthing Switches

All type and routine tests applicable to the earthing switches specified shall be carried out in accordance with IEC 62271-102.

6.8.9.6 Aluminium Welds

Examination and testing of aluminium welds of manufacturer’s works and at Site shall be in accordance with the welding specification submitted to and approved by the Employer.

6.8.9.7 Temperature Rise of Busbars and Evaluation of Losses

(1) A test shall be made on the equipment for each unit to demonstrate that the completed installation complies with the specified temperature rise limits and to determine the losses.

(2) the Employer will provide the current for the test by running the associated generator at rated frequency and excited to give full load conditions.

(3) The Contractor shall provide and install the short circuit connections at the generator transformer terminals and shall provide all the necessary test apparatus. Metering CTs supplied under this Contract may be used in these tests if approved test certificates are supplied before the test.

(4) On completion of the tests, the Contractor shall remove all test equipment and temporary connections from the busbars, etc., and shall return the whole of the plant to a condition ready for service

(5) It is anticipated that the tests will be made at night or on a cloudy day with wind speed not exceeding 15 km/h.

(6) If the Employer considers that weather conditions are such that “stable temperature rise conditions” will not be obtained at the end of the test, the test shall not be started. Stable temperature rise conditions will be considered to occur


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if during the hour preceding the end of the test no rain has fallen and the wind speed has not exceeded 15 km/h. Not withstanding the foregoing, if the Employer considers that any condition occurring during the tests will invalidate the measurements or correction factors, the test shall be repeated.

(a) Temperature Rise Measurements

Approved temperature detectors shall be installed in such numbers and positions as will represent accurately the temperature of the various parts of the busbar, bus ducting, supports, piping and other Plant, building, etc., for which temperature rise limits are specified. The temperature rise of the star point connection shall also be measured. The number and location of detectors shall be determined by mutual agreement.

Temperature rise tests shall be continued until readings taken at regular (15 minutes) intervals indicate to the satisfaction of the Employer that a substantially constant temperature has been obtained.

No correction factor shall be applied to the temperature rise measurement on the equipment within the building.

Temperature rise measurements on equipment external to the building shall be corrected for solar radiation on natural aluminium surface by adding 15°C.

The adjusted temperatures shall not exceed the temperatures specified.

(b) Evaluation and Measurement by Losses

The losses shall be measured by an approved method at the end of the temperature rise test, i.e. when stable temperature rise conditions have been reached. For this test the generator will be operated at its MCR current.

Voltage connections for the test shall be made at the generator terminal stalks.

The Contractor shall describe his proposed method of measurement (equipment, connections, etc.) and state the expected accuracy of the measurement.

(c) Correction Factors

For the purpose of comparison with the guaranteed losses and for the assessment of liquidated damages, if applicable, the measured correction shall be made by assuming the losses to be purely resistive, i.e., no stray loss component and the temperature applicable to the measured losses (before correction) shall be the average of the temperatures measured on each phase busbar at two locations, viz., midway between the turbine block and the turbine house wall and the generator transformer terminals, that is, the average of six readings.

(d) Determination of Stray Heating Effects


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Clause 6.5.1.15 requires that shielding be provided if necessary to prevent overheating of the reinforcing bars in the generator foundation block. To determine the need for such shielding, approved wire mesh reinforcement mats shall be placed against the concrete in approved locations and the temperature rise of the mats determined during the busbar temperature rise test. If the temperature rise exceeds 30°C an approved form of shielding shall be provided at the Contractor’s expense.

Dished Spring (“Belleville”) Washers

Each batch of “Belleville” washers shall be segregated so that random samples can be obtained for testing. The number of sample washers required for testing shall be not less than five washers of each size.

Each washer chosen as a sample for the following test shall be treated for rust proofing as prescribed in Clause 6.5.1.9 of this Specification prior to these tests.

Each washer in the sample shall be subject to a flattening test. A load not less than the flattening load stated in Clause 6.5.1.9 shall be applied and when the load is released the total height (thickness + dish dimension) shall not be less than the figure stated in Clause 6.5.1.9. This application and removal of pressure shall then be repeated 20 times in quick succession, after which the total height shall not be reduced nor the washer show any signs of cracking.

If two of the tested samples fail to pass this test, the whole batch may be rejected.

If one only of the tested samples does not meet the specified requirements, a double quantity of washers chosen at random from the remainder of the batch shall be submitted to the same test.

If all of the retest samples withstand the specified flattening load without failure, the whole batch of washers shall be considered to have passed this test.

If any of the retest samples fail to pass this test, the whole batch may be rejected.

Every washer in each batch sample passing the flattening test shall be further tested by compressing each washer separately against a flat surface with a load of 90% of the flattening load stated in Clause 6.5.1.9. The washers shall be maintained in this condition for a minimum period of 12 hours at a temperature no higher than 0°C and then allowed to remain at room temperature for a further 12 hours. The tested washers shall neither fracture nor crack, and when released they shall return to the original dished shape and total height. If two of the tested samples fail to pass this test, the whole batch may be rejected. If one only of the tested samples does not meet the specified requirements, a double quantity of washers chosen at random from the remainder of the batch shall be submitted to the same test. If all of the retest samples withstand the specified 24-hour load test without failure, the whole batch of


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washers shall be considered to have passed this test. If any of the retest samples fail to pass this test, the whole batch may be rejected.

Every washer in each batch sample shall be subject to a diamond pyramid test and shall be within the limits of 400/500 DPN or its equivalent by other suitable hardness testing machines.

6.8.9.8 Aluminium Welding Tests

(1) Procedures

The Contractor shall submit his welding procedures for approval six months prior to the commencement of fabrication.

(2) Proficiency

The Contractor shall have his factory welding personnel available for welding proficiency tests three months before factory fabrication is to commence. Similarly, Site welding personnel shall be available for welding proficiency tests three months prior to Site fabrication commencing. It is the responsibility of the Contractor to organize the venue and date for conducting the welding proficiency tests.

(a) Approval testing of welds testing shall be in accordance with ISO 9606-2/1994.

(b) On designed joints advised to the Contractor, the Employer may carry out non-destructive testing, including radiography in accordance with ISO 3777/1976 and ISO 2437/1972.

(c) The amount of non-destructive testing will initially be a minimum of 20% of the welding on designated joints, reducing to 5% if consistently acceptable welds are achieved.

(d) The Contractor shall supply to the Employer arrangement Drawings showing designated joints made by each welder and the date of welding.

(e) The Contractor shall give five working days notice to the Employer that

(i) The first batch of designated welds by each welder and

(ii) Further batches of designated welds are available and shall provide adequate access at the shop and Site for testing in normal working hours.

(f) The Contractor shall carry out radiography of repair welds on designated joints at his own expense to the satisfaction of the Employer.

(3) Requirements in offering porcelain insulators:

(a) Insulators shall be tested in accordance with IEC 60168.

(b) Type test certification will be required from the manufacturer six months prior to commencing manufacture of the insulators.

(4) Requirements of offering resin epoxy insulators:

(a) Insulators shall be tested in accordance with IEC 60137.


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(b) A type test certificate is required.

6.8.10 Generator Circuit Breakers

The following clauses are applicable.

The Contractor shall state what testing facilities he has at the manufacturer’s works in order to carry out:

(a) Electrical tests.

(b) Mechanical tests to prove the strength, hardness and other physical qualities of the materials employed in construction.

The Contractor shall submit certified results of any design tests called for in this Specification to which the works or any component parts thereof have been subjected. the Employer may accept any or all of these tests in lieu of those specified herein.

6.8.10.1 Subcontractors

The Contractor shall include in the proposal documents details of all components which he proposes to have made by Subcontractors to the main circuit breaker supplier and the names of such Subcontractors so that if required arrangements may be made for the necessary inspection and testing of such components at the works of the Subcontractor.

6.8.10.2 Complete Circuit Breakers - Design Tests

Design tests in accordance with IEEE Standard C37.013 (Clauses 5.2 to 5.2.13) shall be carried out. The Contractor shall submit certified results for the design test to the Employer. The certified results shall conform to the guarantees stated in the Contract.

If the design tests have already been carried out the Employer may accept certificates in lieu of repeating those tests.

6.8.10.3 Complete Circuit Breakers - Production Tests

Production tests shall be made on every circuit breaker in accordance with IEEE Std C37.013 (Clauses 5.3 to 5.3.13), subject to the following additions. The test values and results shall conform to the guarantees stated in the Contract. Prior to shipping adequate production tests should have been performed to ensure that every component of every circuit breaker has been correctly assembled and is functioning correctly.

In addition to the production tests the following shall be carried out:

(1) An ohmic resistance test on each trip and closing coil, and

(2) A timing test on the auxiliary contacts to demonstrate correct operation and relationship with the main contacts.

6.8.10.4 Tests at Site

(1) Tests by the Contractor


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On completion of erection of the circuit breakers and associated control panels the Contractor shall carry out the “tests after delivery” in accordance with IEEE Std C37.013 (Clauses 5.4 to 5.4.7) subject to the following additions:

(a) Insulation resistance of control panel wiring;

(b) Confirm correct operation of tripping and closing circuits; and

(c) Confirm correct operation of auxiliary contacts.

The Contractor shall advise any additional “tests after delivery” he proposes to carry out.

(2) Tests by the Employer

the Employer shall have the right to carry out such tests as it deems necessary to prove the compliance of the Plant with the Contract. Such tests may include repetition of tests carried out at the maker’s works (modified in intensity and value where provided in the relevant standards). the Employer may also carry out such field tests with the circuit breakers connected to the system as is deemed necessary to prove:

(a) The ability of the circuit breakers to de-energies unloaded transformers,

(b) The switching overvoltages resulting from operation of the circuit breakers do not exceed the value specified.

Tests at Site during the Maintenance Period.

the Employer shall have the right to carry out during the maintenance period.

6.8.11 Diesel Generators

The following clauses are applicable.

6.8.11.1 Works Tests

(1) Performance tests of each Diesel generator at the manufacturer’s works shall be to ISO 3046/2. The tests shall be used to prove the performance guarantees. It shall be witnessed the Employer. All costs and expenses involved in conducting such tests shall be borne by the Contractor.

(2) The Diesel generator shall not be dispatched until proved satisfactory in the acceptance tests.

(3) All auxiliaries such as air compressors, receivers, fuel tanks, exhaust systems, pumps, cooling towers, oil coolers, switchboards shall be tested to relevant standards and approved by the Employer before dispatch to the Site.

6.8.11.2 Site Tests

(1) Upon completion of erection, the Contractor shall carry out all necessary checks, adjustments and trial running. All costs (including Diesel fuel and oil) and expenses involved in conducting such tests shall be borne by the Contractor.

(2) Testing of auxiliaries such as air compressors, air receivers, fuel system, cooling water system, air intake and exhaust system, battery and charger, control panel


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and switchboard shall be individually carried out to validate its performance and control settings.

(3) Running tests of the Diesel generator for a minimum 5 working days 7 hours per day continuous operation without failure shall be carried out. During this test the Contractor shall record all measurements and submit for approval of the Employer. The loads during this test shall be varied from 25% to 110% and the diesel generators response to load pick-up shall be ascertained.

(4) At least 7 hours continuous running on full load shall be included in the running tests.

6.8.11.3 Commissioning Tests

(1) When the diesel generator has been proved satisfactory by the running tests, the Commissioning tests shall commence. All costs (including Diesel fuel and oil) and expenses involved in conducting such tests shall be borne by the Contractor. These tests will include, but not necessarily be limited to the following:

(a) Establishment of plant status at commencement.

(b) Open circuit test and automatic voltage regulator test.

(c) Synchronizing and loading for three repeat tests.

(d) Remote starting capability for three repeat tests.

(d) Periodic load test capability for three repeat tests.

(f) Reliability of the starting gear for 5 consecutive starts.

(2) The Contractor shall, during the Commissioning tests, be responsible for adjusting and operating the diesel generator.

6.8.12 High voltage Switchyard system

6.8.12.1 Test and Commissioning

The Contractor is responsible for carrying out all tests required before the switchyard is put into service.

6.8.12.2 Pre-commissioning Tests

Following erection of equipment on Site and installation of the various systems, Precommissioning checks shall be carried out in accordance with the relevant sections in the Contract documents and the manufacturers’ instructions.

Some typical pre-commissioning tests are:


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(1) Wiring continuity tests.

(2) Megger (DC insulation resistance) testing of equipment.

(3) Alignment of equipment.

(4) Calibration of instruments.

(5) Relay settings.

(6) Injection to prove operation of relays and protection schemes.

(7) Saturation, ratio and internal resistance checks on CTs.

6.8.12.3 Commissioning Tests

Following completion of the works and the Pre-commissioning tests, the Contractor shall carry out testing and Commissioning in accordance with the Contract documents and which shall include, but not be limited to the following:

(1) Busbar balance checks.

(2) Transformer differential HV and LV balance checks.

(3) Circuit breaker trip checks.

(4) Operation of communication functions.

(5) Operation of intertrip functions.

(6) Operation of controls systems.

(7) HV testing of relevant Plant.

(8) Service voltage test of connected HV equipment.

6.8.13 Communication system


Testing and Commissioning of the communication equipment shall be performed in accordance with the following specifications.

6.8.13.1 Factory Tests

A type test can be omitted only if the Contractor submits to the Employer a complete and satisfactory type test report issued by an independent and recognized laboratory.

6.8.13.2 Type Tests

The following type tests shall be performed:

a. Testing of table telephone set with horn and flashing lamp (dialling speed, microphone feeding current, automatic line regulation, frequency range, side tone equivalent, reference equivalence, etc)

b. Verification of cameras, TV monitors characteristics;


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c. For optical fibre cables, type tests shall be carried out as follows:

i. Repetitive Tensile Test

ii. A specimen length of 10m shall be used and the gauge length shall be 5m;

iii. The initial tensile loading shall be 8% and the following loading schedule shall be applied:

Initial - 30% UTS (0.5 hour hold);

Initial - 50% as (1 hour hold);

Initial - 70% III'S (1 hour hold);

Initial - 95% UTS (0.5 hour hold).

iv. This cycle should be repeated five times with the specimen being held at 95% UTS for 3 hours on the last cycle;

v. During this test, the optic fibre shall be spliced in series and the optical attenuation measured throughout the test using a laser LED or power source and meter or an optical time domain reflect meter.

d. Ultimate Tensile Strength (UTS) Test

i. Following completion of the fifth cycle of (c) above the specimen loading shall be increased up to breakage of the composite earth wire or up to the specified UTS of the earth wire;

ii. Breakage shall not occur below the specified UTS. Attenuation shall be monitored as in the Clause (c) above.

e. Cable Test

i. Creep tests shall be performed using a constant tension device at 30°C for both 20% and 40% UTS for a period of 1000 hours. During these tests the attenuation shall be monitored as in (c) above.

Vibration proof characteristics;

Short circuit current test;

Arc discharge test;

Optical fibre cable:

ii. Type, sample and routine tests shall be carried out on optical fibre cable and accessories in accordance with the appropriate clauses of IEC 60793-1-1, IEC 60079 and ANSI/EIA standards.

6.8.13.3 Routine Tests

f. The following routine tests shall be carried out at the manufacturer's work on any or all of the components and the system in accordance with the requirements set out in latest issue of relevant publications.

i. Visual check to verify conformity with the Specifications;


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ii. Verification of CCTV control unit characteristics (operating facilities, operating voltage, etc);

iii. Verification of video recorder characteristics;

iv. Verification of amplifier and speaker characteristics.

v. The Contractor shall submit all routine test reports of manufacturer to the Employer for approval.

6.8.13.4 Site Tests

g. The Contractor shall be responsible for giving instruction and supervising Site tests for his equipment in accordance with the Contract.

h. The Contractor shall submit a testing list for the equipment, with test report forms and detail instructions.

6.8.13.5 Power Supply

i. The modular power supply shall be tested and commissioned in accordance with the manufacturers’ installation manual. Voltage limit levels for alarm conditions shall be set, and time intervals shall be set for the battery monitor module to test the batteries.

6.8.13.6 Alarm Panel

j. The panel shall be tested in accordance with the suppliers’ instructions. An earth shall be placed on the alarm wire at each apparatus to verify that the alarm operates correctly

6.8.13.7 Exchanges and Telephones

k. The exchanges shall be tested and commissioned to meet the approved signal levels for the connection to the public network, to the multiplex channels on the OPGW and to individual extensions. All features shall be tested and demonstrated and operating satisfactory.

6.8.13.8 30 Day Test

l. At the completion of the equipment and system tests, a 30 day operational system test shall be carried out covering the main and back-up exchanges, the Paging and UHF radio systems.

m. During this period, faults affecting more than 20% of users shall terminate the test. The fault shall be rectified to the satisfaction of the Employer and another 30 day test restarted.

n. These tests shall be completed prior to the commissioning tests for the power station.


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6.9 Coal Handling Plant

The power transformers associated with coal handling plant shall be dry type. The power transformers shall comply with the specifications detailed in Volume 2.

6.9.1 Low Voltage Switchboards and Switchgear

Switchboards and switchgear associated with coal handling plant shall comply with the appropriate specifications detailed in Volume 2.

6.9.2 Electrical Field Devices - Safety and Control

6.9.2.1 General

The Contractor shall provide all safety switches and devices to ensure satisfactory operation of the plant.

6.9.2.2 Enclosures

Enclosures for electrical safety devices mounted on or about the plant shall be robustly constructed, and comply with the requirements of Volume 2.

6.9.2.3 Limit Switches

Limit switches shall generally be of the proximity type.

Where there is no likelihood of limit switches being subjected to vibration and/or dust, the use of limit switches of the encapsulated reed type may be permitted, subject to suitability for fault current switching.

6.9.2.4 Tail Pulley Coal Build-up Switches

Tail pulley coal build-up switches and operating mechanisms shall be provided by the Contractor for each conveyor belt.

Tail Pulley Build-up switches shall reliably detect build-up of entrapped objects with thicknesses of greater than 5 mm over the entire width of the belt. The Contractor's scope includes design, supply, installation and commissioning of a suitable activating mechanism.

The tail pulley build-up switches shall require a low energy of actuation, but shall be immune to vibration.

6.9.2.5 Belt Tracking Switches

Devices shall be provided to detect a lateral movement of each conveyor belt.

6.9.2.6 Emergency Stop Switches

Typically, each conveyor shall be provided with emergency stop switches of two types: lanyard type and mushroom head push off type. The lanyard type switches shall be installed both sides of the conveyor while the mushroom head type shall


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be installed at the head and tail ends of the conveyor and on local control stations for drives.

Each emergency stop switch shall be equipped with two contacts - one normally closed contact which is relayed into the belt drive contactor circuit outside the Control System; the other is a normally open contact which is wired to the Control System discrete input module.

6.9.2.7 Ultrasonics

An ultrasonic transmitter/receiver unit shall be installed at each of the discharge points for each boiler bunker where Trippers 1A, 1B discharge coal. Each ultrasonic unit shall determine the distance from the unit to the coal level below each tripper discharge point. The level signals shall be processed by separate control units whose 4 to 20mA outputs shall be multiplexed to an analogue input module of the Control System.

The level signals shall be used to enable/disable the discharges of coal from reclaimers. The signals shall also be transmitted to the HMI screen for display.

6.9.3 Electrical Protection Equipment

Electrical protection equipment shall be supplied, installed, tested and commissioned by the Contractor for each MV and LV circuit associated with the coal handling plant.

Electrical protection equipment associated with coal handling plant shall comply with the appropriate specifications detailed in Volume 2.

6.9.4 Local Control Stations

The Contractor shall supply, install., test, and commission all Local Control Stations necessary for the safe local control operation of coal handling plant,

With each conveyor belt drive, shuttle drive, magnetic separator, tramp iron magnet, belt weigher, washdown solenoid operated valve and other similar item of plant supplied under the Contract, the Contractor shall provide a separate local control station (LCS).

The local control station for a conveyor belt drive shall be mounted adjacent to the drive.

Each conveyor belt and shuttle LCS shall be arranged so that an operator can readily observe the associated drive or other item of plant.

6.9.5 Actuators for Retractable Skirts, Gates, Swing Chutes, Shuttle Heads

The Contractor shall provide electric actuators for power operated gates, retractable skirts, shuttle heads and other equipment as specified.

The Contractor shall supply detailed information for each actuator


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6.9.6 Motors

The Contractor shall supply, install, test and commission all electric motors associated with coal handling plant.

Electric motors associated with coal handling plant shall comply with the appropriate specifications as detailed in Volume 2.

6.9.7 Switch room Ventilation Plant

Each switch room and control room shall be provided with a fire and smoke detection system. Upon detection of fire or smoke the ventilation plant for the switch room or control room shall trip immediately to prevent fresh air fuelling the fire.

Each ventilation system shall incorporate bag type filters with an automatic cleaning system. The contractor can also offer the CHP switch room with under positive pressure ventilation plant and air conditioning system.

The ventilation units shall incorporate bag type filters with an automatic cleaning system initiated from a filter differential pressure switch. Details of the self cleaning process shall, be submitted with Tender. No compressed air supply is available.

The bag filters shall remove in excess of 99% of airborne dusts.

The bag material used shall be such that the bags will allow easy release of materials typically entrapped in an environment of airborne moisture and coal dust and will not deteriorate through contact with the moist coal dust.

The Bidder shall submit with the Bid details of the bag material proposed, life expectancy of these bags in the specified environment and costs of a set of replacement bags. One set shall be included as a consumable spare.

Dust released following an automatic cleaning sequence shall be contained in a vessel that is readily accessible for emptying purposes.

The vessels shall be lined with a material that resists corrosion due to moistened coal dust. The vessels shall be removable without the need for tools.

The units air intakes shall be provided with mechanical protection that will prevent the ingress of large objects or vermin. The intake shall be flared to reduce air velocity.

The Contractor shall provide an air relief damper mounted in the switch room wall or door in a position that ensures a diagonal crossflow of air and maintains a positive pressure.

The Contractor shall provide ventilation unit local control stations in accordance with this Specification.

The system shall be provided with an alarm which shall be activated by a pressure switch mounted in or adjacent to the system ductwork when the air pressure falls below required level. The alarm shall be displayed in the PCR.


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The fire detection system shall be arranged to shut down the ventilation plant and prevent its starting if fire or smoke is detected in the switch room.

6.9.8 Switch room Layout

Switch rooms shall be fully dustproof and weatherproof.

Switchboards shall be arranged in parallel rows and over trenches (if applicable).

Adequate clearances shall be provided to allow for the possible removal of the transformers from the switch room.

Switchboards facing each other shall have sufficient clearance between them to allow full withdrawal of both sets of switchgear and still leave additional clearance for personnel.

Switch rooms shall be 2 hour fire rated.

Cable access to switchboards shall be from below the switchboard.

Cable trenches not covered by switchboards shall be covered by 8 mm floor plate covers which shall be supplied and installed by the Contractor.

The switch room shall be large enough to accommodate the following plant' and equipment :

switchboards as required by the Contractor's design; batteries and chargers as specified and in a separate forced ventilated

room; control system enclosures as required by the Contractor's design; transformers; fire protection cabinet; MP&L dist. board; other equipment required by the Contractor's design.

Fire protection cabinets shall be mounted on the wall inside the switch room adjacent to a personnel access doorway.

An approved carbon dioxide fire extinguisher shall be provided for the switch room by the Contractor.

A clipboard capable of holding the Employer's Standard A2 size prints shall be provided on one wall of the switch room.

Switch room doors shall be metal clad two-hour fire rated and fitted with robust, long lasting dustproof seals. Doors shall be automatically forced closing.

Door sealing strips shall be manufactured of neoprene and shall mate with surfaces of the same or larger width. The sealing strips shall be effectively retained.

All outside surfaces of walls shall be weatherproof. This includes Switch rooms located within other structures.


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6.9.9 Cabling

The Contractor shall supply and install all cables, conduits, ducts, trays and terminating equipment associated with all items of plant in accordance with this clause and the specification detailed in Volume 2.

6.9.10 Control System

In carrying out the work under this Contract as specified the Contractor shall comply with the requirements of Volume 7.

Where two conveyor systems, A and B, operate in parallel the Contractor shall arrange input/output modules so that devices on Conveyor System A shall be connected to one set of input/output modules and the devices on Conveyor. System B shall be connected to a separate set of input/output modules. The failure of one input/output module for Conveyor System A shall result in the stopping of the train in which Conveyor System B is an element but shall not result in the crippling of Conveyor System B.

The Contractor shall supply, install and terminate all wiring within the control system enclosure and all cabling entering the enclosure.

6.9.11 Stacker, Reclaimer and Stacker/Reclaimer - Electrical

Due to the lengthy cable routes from Switch room it is expected that power supplies to each stacker, reclaimer and stacker/reclaimer shall be at high voltage. One dry type MV/LV transformer shall be provided on each machine closely coupled to the Motor Control Centre (switchboard) on board the machine structure. The transformer shall be connected to incoming power cabling via medium voltage isolating and earthing switches in an adjacent enclosure.

Each of these machines shall be provided with whole current limit switches which, when operated by overtravel targets at each end of the track, interrupt power supply to the long travel drives.

Each of these machines shall be provided with an anemometer which, when high winds are detected, shall initiate shut down of the stacking functions (after belt purging), drive the machine to the tie down area and lower the boom to the tie down position.

Each stacker boom is to be provided with anti-collision wires on each side of the boom to detect obstructions such as coal pile, dry storage structure, reclaimer. The wires shall operate switches when the wires meet an obstruction and the switches in turn shall trip all tripper/stacker functions. This function shall be available in all control modes.

The discharge end of each boom is to be provided with tilt switches which detect the height of the coal pile. The switches shall be input to the control system and used for stacker operating control functions.

The boom raising & lowering hydraulic system is to be provided with limit switches at discrete angles for control purposes.

Each stacker, reclaimer and ploughs shall be equipped with the following:


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brake motor blocked chute detector bunker level detection system ( For ploughs) whole Current overtravel limit switches, emergency stop switches cable reel system

The reclaimer shall be provided with whole current limit switches which, when operated by overtravel targets at each end of the track, interrupt power supply to the long travel drives.

Long Travel Drives:

Long travel AC motor drives for tripper, stacker and reclaimer machines shall have variable frequency controllers for speed and torque control. Motor fans shall be independently powered.

6.9.12 Ship/Barge Unloader - Electrical

The Electrical work scope for the barge unloader is as follows:

o cable reel system;

o main switchboard;

o motor control centre;

o distribution switchboard for lighting and power;

o variable speed drives and or solid state control for DC motors (Refer Volume 2);

o control system for control and monitoring of all operations and functions (Refer to Volume 7);

o alarm, indication and control panel in the operator's cabin;

o control console in the operator's cabin;

o control station on stair landing for long travel boom lowering and rising;

o DC motors for grab lift and grab opening/closing;

o DC motors for grab long travel;

o AC motor for boom raising and lowering;

o AC motor for operator's cabin travel;

o AC motor with variable frequency driver for the belt conveyor;

o AC motor for hopper vibration;

o AC motors, brakes and drivers for long travel;

o Others

(a) Trailing Cable


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The Contractor shall provide a 6.6 kV three-phase trailing cable and associated cable reel system complete with torque control motor and slip ring column.

The entire system shall include the following:

6.6 kV three-phase cable of adequate size to provide minimum 50% spare current carrying capacity above the estimated maximum demand of the unloader electrical equipment;

six fibre optic cables;

minimum three control cable cores concentric within the earth conductors;

minimum one earthing conductor;

one pilot earth conductor for earth continuity monitoring.

The fibre optic cable cores, the earth and control cables and the medium voltage cables shall be terminated in three separate enclosures. The cores of the fibre optic cable shall be terminated within the electrical equipment room within a splicing box, including spare cores.

(b) Grab Hoist Carriage

The grab hoist carriage and hoist drives and controls shall comply electrically with the appropriate crane code. The carriage shall be provided with overtravel limit switches which upon operation shall trip the carriage drives.

Power supply and control cabling to the hoist carriage shall be a catenary system comprised of suitable tracks and trolleys. Undertension and overtension limit switches shall be provided to trip carriage long travel drives should the catenary trolleys fail to move correctly or the cabling break away.

Carriage and hoist AC motor drives shall have variable frequency controllers for speed and torque control. Alternative methods will be considered.

(c) Unloader Long Travel Drives

Long travel AC motor drives shall have variable frequency controllers for speed and torque control. Alternative methods will be considered.

The unloader structure shall be provided with current operated limit switches, which upon operation shall trip the long travel drives.

(d) Surge Hopper Level Detection

High level tilt switches (two per hopper) shall be provided to disable the grab bucket release mechanism until the hopper coal level is low enough to accept the bucket load.

If the hopper outlet is fitted with vibratory feeder(s), microwave level system shall be provided to shut down the feeder when the coal level drops below the


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microwave sensor level. Feeders would be enabled whenever the hopper level is above the sensor level.

(e) Cable Reel Systems

Under tension and over tension limit switches shall be provided to trip unloader long travel drives should the cable reel fail to move correctly or the cabling break away.

(f) Power Supplies

Due to the lengthy cable routes from Switch room it is expected that power supplies to each grab unloader shall be at medium voltage. One dry type transformer shall be provided on each grab unloader closely coupled to the Motor Control Centre (switchboard) on board the grab unloader structure.

The transformer shall be connected to incoming power cabling via medium voltage isolating and earthing switches in an adjacent enclosure.

The dry type transformer, if mounted outdoors, shall be housed in a IP56 steel enclosure equipped with an air/air heat exchanger. The enclosure shall be shaded from the sun. An IP23 enclosure shall be acceptable in a switch room designed with a filtered and pressurized air supply.

Earthing cores shall be provided in each trailing cable for power supply earthing purposes.

Rails shall be connected to the lightning earthing system. Each grab unloader shall be provided with lightning rod, down conductors and brushgear to rails.

(g) Lighting

Each grab unloader shall be provided with floodlighting so the operator can view the grab, barges and top of surge bin at night and in other poor lighting conditions.

(h) Strong Wind Precautions

Each barge unloader shall be provided with an anemometer which, when high winds are detected, shall initiate shut down of the unloading functions, drive the machine to the maintenance area and raise / lower the grab/bucket to the tie down position.

(i) Blocked Chute Detection

Chutes below vibratory feeders leading to conveyor loading skirt boxes shall be provided with tilt switches which detect blocked chutes. The switches shall input to the Control System and after a suitable time delay, trip the vibratory feeders.

6.9.13 Sampling System - Electrical

(a) The power supply for each sampling system shall be derived from a dedicated CFS or circuit breaker at the appropriate motor control centre.

(b) Each sampling system shall be controlled by the Control System.


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(c) Each sampling system shall have a local control station where local or remote control may be selected.

6.9.14 Weighers - Electrical

(a) High accuracy weighers shall be installed on conveyors.

(b) Coaling rates in t/h shall be to be separately transmitted to the Control

System.

(c) Each belt weigher shall have a local control station.

6.9.15 Tramp Iron Magnets and Metal Detectors

(a) Tramp iron magnets shall have a local control station incorporating the

transformer/rectifier set, control selector switch and main power switch.

Analog quantities such as magnet voltage and current shall be derived

using transducers and input to the Control System.

(b) Tramp iron magnets shall be energized whenever the associated conveyor

is running.

(c) Tramp iron magnets shall be supplied with a self cleaning belt which shall

cycle every 20 minutes with a start/run for 1 minute/stop cycle. The cycle

shall be enabled when the associated conveyor is running and there shall

be one cycle immediately the conveyor stops.

(d) The self cleaning belt drive shall be provided with a local control station.

(e) Metal detectors shall be provided with a local control station, a lamp

indicating metal has been detected and a marker release mechanism which

drops a marker on the belt at a point where metal has been detected. This

mechanism shall be installed sufficiently downstream of the detector to

enable correct identification of the tramp metal.

(f) Metal detectors shall communicate relevant functions to the Control

System.

6.9.16 Hydraulic Systems - Electrical

(a) Hydraulic systems comprising drive motors, pumps, reservoirs, valves and

piping shall be installed on the stacker and the reclaimer to enable

functions such as boom raising to be performed.

(b) Pressure switches, oil level switches, valve position limit switches and

valve actuators shall be provided for safety and control purposes.


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6.9.17 Cable Reel Systems

The Contractor shall provide separate Medium Voltage cable reel and control cable

reel systems for:

- Barge Unloader A

- Barge Unloader B

- Barge Unloader C

- Traveling Stacker machines

- Traveling Reclaimer machine

- Travelling Stacker / Reclaimer

The Contractor shall provide separate 400V cable reel / catenary and control cable

reel /catenary systems for:

- For Tripper 1A

- For Tripper 1B

6.9.18 Contract Drawings

The drawings and information requested in technical schedules shall be completely filled in by the Bidder.

Notwithstanding the requirements of the technical schedules during various design phases of the Contract, the Contractor shall submit.

General arrangement information and details of all machinery and equipment:

Sectional views of filter units, compressors gearboxes motors and couplings,

detailed to show relative parts.

Drawings, diagrams, and calculations showing design data_ stresses, loadings, etc.,

adopted to all equipment and structures.


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6.10 SPARE PARTS

6.10.1 General

Spare parts for the plant covered by this section shall generally be supplied in accordance with the Contract.

Essential spares shall comprise at least the items as listed below and as detailed in the list of the relevant essential spares of Volume for electrical Plant. Optional spares shall be in accordance with the manufacturers’ recommendations for parts which may fail and require replacement.

6.10.2 Essential Spares

The following items shall be provided per unit:

6.10.2.1 Generator

(a) One (1) generator set of shaft journal bearings, comprising top and bottom halves, complete with bolts, nuts and lockwashers.

(b) One (1) generator set of bearing and pedestal insulation.

(c) One (1) turbine-generator set of shaft earthing and voltage sensing brushes.

(d) Sufficient top and bottom stator winding bars to repair a fault in the worst location; supply to include all associated items necessary for the repair including hoses, fittings, wedges and packers etc.

(e) One (1) turbine-generator set of generator access doors and shield gaskets.

(f) One (1) turbine-generator set of brush gear including arms, brush boxes, springs.

(g) One (1) generator set of slip rings.

(h) One (1) generator terminal bushing

6.10.2.2 Excitation System

(a) One (1) of each type of automatic excitation controller printed circuit card.

(b) Number of thyristor units equivalent to the amount of redundancy in one arm of a thyristor bridge - refer to Volume 2; each unit consisting of the valve and associated control and protection components.

(c) One (1) thyristor bridge cooling fan/motor unit

(d) One (1) field circuit breaker set auxiliary contacts.

(e) One (1) field circuit breaker set arcing tips.

(f) One (1) field circuit breaker set suppression resistors.

(g) One (1) field circuit breaker set closing and trip coils.


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6.10.2.3 Hydrogen Cooling System

(a) Hydrogen / CCW cooler

5% of the cooling tubes

Tube plugs of number equivalent to 10% of the total number of tubes.

Four (4) sets gaskets for the manholes and water boxes

Four (4) sets of special gaskets for each heat exchanger

(b) Valves and Fittings

Two (2) valves of each type and size

Two (2) sets of renewable parts of valves for each type and size

20% of sight flow indicator installed

One (1) set of filter basket for each type

6.10.2.4 Seal Oil System

(a) Seal oil pumps

One (1) set of bearings for each pump.

One (1) set of wearing rings and bushes.

Two (2) sets of packing and special gaskets for each pump

(b) Seal Oil Cooler

5% of the cooling tubes.

Tube plugs of number equivalent to 10% of the total number of tubes.

Four (4) sets gaskets for the manholes and water boxes.

Four (4) sets of special gaskets for each heat exchanger.

(c) Valves and Fittings

Two (2) valves of each type and size.

Two (2) sets of renewable parts of valves for each type and size.

20% of sight flow indicator installed.

One (1) set of filter basket for each type.

6.10.2.5 Medium (6.6kV) and Low (400V) voltage system

(a) One 6.6kV and 400V circuit breaker of each type and rating.

(b) One 6.6kV switching device of each type and rating.

(c) One 6.6kV motor of each type and rating.

(d) One actuator of each type/function/rating.

(e) The 400V switchboards shall be designed to incorporate 10% more circuits than the number specifically identified as being required for the plant. Spare circuits shall be fully equipped wired and tested with all electrical equipment other than CTs. Spare circuit ratings shall


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include the complete range of ratings used for plant operation but shall comprise mostly lower rated rather than higher rated circuits. The ratings and numbers chosen shall be subject to agreement with the Employer.

(f) One transformer bushing of each type and rating.

6.10.2.6 Control Devices

(a) Six fuses of each type and rating.

(b) Four TRIP coils and four CLOSE coils of each type and rating

(c) Four control relays of each type and rating.

6.10.2.7 Cables

One steel drum (wooden drums are not acceptable for spares usage) containing 250 meters of each type of 6.6kV cable. A separate steel drum shall be provided for each cable size.

6.10.2.8 High Voltage Switchyard system

High Voltage Switchgear

No. Items Qty

(220kV side)

a) Circuit Breakers

- Interrupter - 1 phase 3

- Support columns 3

- Capacitors - 1 phase 3

- Auxiliary interrupter 3

- Insulators 1

- Operating rod 1

- Contacts - 1 phase 3 set

- Trip/close coils 10

- Auxiliary switches 2

- Relays/contacts 2 set

- Operating springs 1

- Operating mechanism 1

- Accumulator - 3 phase 3

- Hydraulic valves 2

- Pressure switches 2

- Motors 2

- Drive linkage 1 chain


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No. Items Qty

(220kV side)

- Desiccant 2

b) Current Transformers

- CT Post 3 each

c) Voltage Transformers

- VT Post 3

d) Disconnectors

- Fixed/moving contacts - 3 phase 2 set

- Motor 1


- Relays/contacts 2 set

e) Earth Switches

- Fixed/moving contacts - 3 phase 2 set


f) Insulators:

- Post 3 each

g) Surge Arrestors:

- Unit 1

(a) Protection Systems

Complete spare relays shall be provided for every type used for protection purposes.

The quantity provided for each type shall be 5% of the total number of that type or one (1) unit, whichever is the greater.

(b) Electrical Works

No. Items Quantity

a) Disc Insulators:

- 220kV String 1 set

b) Conductor Clamps, Fittings: 6 each

c) ACSR Conductor (Each size) 100 metres

d) Kiosk and Panel Equipment:

- Terminal blocks, fuses, links, cable glands etc 10 each

- Auxiliary relays etc. - each type 5 each

e) 220 V Batteries:


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No. Items Quantity

- Cells 20 each

f) Battery Chargers:

- Printed circuit boards – complete replacement set (mother board not included)

1 each

- Main diode - complete replacement set 1 each

- Thyristor - complete replacement set 1 each

g) DC Distribution Boards

- Relays - each type 1 each

- Fuses - each type each 10

h) AC Distribution Boards:

- Contactor contacts - set 3 each

- Contactor coil 1 each

- Circuit breakers - each type and rating 1 each

6.10.2.9 Communication systems

(a) Technical Services

Spares shall cover:

Rapid restoration spares comprising replaceable sub-units such as power supplies and printed circuit cards - 10% of total, with a minimum of one (1).

Component parts to enable a faulty sub-unit to be repaired in a central workshop - 5% of total.

(c) Radio Paging, UHF Radio and Emergency Warning Systems

Radio paging system:

Pagers, vibrating type - unit 2

Pagers, audible type - unit 3

UHF Radio System:

Radios, hand-held mobile - unit 1

Radios, fixed - unit 1

(d) Emergency Warning System:

Spares shall cover

Rapid restoration spares comprising replaceable sub-units such as power supplies, printed circuit cards, microphones, speakers etc. - 10% of total of each sub-unit with a minimum of one (1).

Component parts to enable a faulty sub-unit to be repaired in a workshop - 5% of total of each part with a minimum of one (1).


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6.10.2.10 Coal Handling Plant

6.10.2.10.1 Indoor Switchboard

The Contractor shall provide 10% of the total equipment and/or apparatus furnished for each type and rating as a minimum for the following.

Bushing insulators

Stationary contacts

Moving contacts

Trip coils

Closing coils

Auxiliary contacts

Auxiliary relay

Springs

Valves

Main contacts

Auxiliary contact

Miniature circuit breaker

Thermal relays

Terminal blocks

Lamp fittings and lens

200% of lamp bulbs

Pushbutton switches

6.10.2.10.2 Auxiliary Power System

The following spare parts as a minimum shall be applied for Coal Handling and Jetty P/C Transformers.

Two (2) sets of bushings for each type used

One (1) set of thermometer for each type complete with accessories

One (1) set of winding temperature indicator for each type used

One (1) piece of auxiliary current transformer for each type used for metering, protection and for accessories

One (1) complete set of contacts and coils for each type used for contactors and relays

6.10.2.10.3 Battery and Charger

Ten (1) spare cells, dry-charged with electrolyte in sealed containers.

Ten (10%) of the total electrolyte used.


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Ten (10) pieces of terminal connector

200% of pilot lamp bulbs for each type used.

20% of fuses for each type and rating.

20% of auxiliary relays for each type and rating.

One (1) set of relay for each type supplied.

100% of thyristor for each type used.

One (1) set of printed circuit boards for each type used for control circuit.

One (1) set of moulded case circuit breaker for each type and rating.

Two (2) sets of terminal board for each type used.

One (1) set of changeover switch for each type used.

6.10.2.10.4 Lighting System

20% of moulded case circuit breaker for each type and rating used.

200% of electric bulb for pilot light.

20% of fuse for each type and rating.

20% of the total number of lamps used for each type and rating.

6.10.2.10.5 Cables

Five percent (5%) of the installed length of each type and rating of cable used. Each spare length shall be conditioned on a reel.

Five percent (5%) of cable terminals and clamps used in cable termination.

6.10.2.10.6 Motors

Two (2) sets of bearing for each type used.

One (1) motor of each type used in valve actuators.

6.10.2.10.7 Other Electrical Parts

Two hundred percent (200%) of normal use of carbon brush for torque motors

Two hundred percent (200%) of normal use of brush for cable drum slip ring

One hundred percent (100%) of normal use of solenoid valve coil

Five percent (5%) of speed switch

Five percent (5%) of chute switch

Five percent (5%) of emergency switch

6.10.2.10.8 Special Tools

One (1) set of special tools necessary for maintenance of the coal handling equipment.


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6.10.2.10.9 Coal Handling Plant Control and Instrumentation

6.10.2.10.10 Essential Spare Parts

Essential spare parts for the supplied control and instrumentation system shall be good for five (5) years operation of the systems specified under special tools and for all other system applicable and shall not be limited to the following:

10% of number of sets of Printed Circuit Board (PCB)/module but not less than one (1) set for each type used

100 pieces of fuse element for each type and rating

20 pieces of base for fuse for each type

12 sets of A/M station (selected)

200 pieces of lamp bulb for each type used

200 pieces of indicator lamp for each system

4 sets of annunciator used for each system

20 pieces of LED for annunciator windows for each control system panel

20 percent of spare of the total number of each panel alarm window

20 pieces of lens for illuminated push button switch for each colour used

10 sets of assembly of control switch for each type used

10 sets of assembly of push button switch for each type used

20 sets of auxiliary relay for each type and rating used

10 sets of "ON" time delay relay for each type and rating used

10 sets of "OFF" time delay relay for each type and rating used

4 sets of timer relay for each type used

5 sets of relay base for each type

3 sets level switch assembly for each type used

5 sets of pressure switch for each type used

2 sets of assembly of level indicator for each type used

5 sets of flow switch for each type used

5 sets of temperature switch for each type used

2 sets of flow meter for each and range used

10 sets of solenoid valve for each type used

set of indicating instrument for each type used

set of indicating meter for each type used

set of diaphragm for each type of actuator for pneumatic control valve


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5 sets of gland packing for each type of control valve

20 pieces of power diodes for each type used in control systems

sets of load cell of each type

set of transmitter (selected range) for each control system with spare parts

set of 3-valve bypass manifold for each type used

set of 9-point test recorder

sets of pressure/hand pump for instrument calibration

300 pieces of fittings for each type and size used

10 percent of the installed length of tubing of each type and size used

Other items according to the manufacture's recommendation

In addition to the above, at least 10% of each type of spare modules including auxiliary relays shall be provided in each control cubicle and control cabinet for the case of the maintenance work. Those spare modules and auxiliary relays shall be suitably fitted in the relevant cubicles and cabinets.

6.10.2.10.11 Special Tools and Maintenance

One (1) set of special tools/calibration test instrument/program loader applicable for the following systems:

Unloader control system

Stacker, Reclaimer and Bucket Wheel Stacker/Reclaimer control system

Conveyor control system

Auto sampler system

Yard management computer

Coal yard spray control system

Others

One (1) set of special tools for all other supplied instruments and controls not covered/mentioned in the above systems but is in the system itself which are necessary for system maintenance and operation. Any special wiring tools for each system shall also be supplied.

6.10.3 Optional Spares

The Contractor shall list in Volume 12 Technical Schedules those optional spare parts which it is recommended should be purchased in additional to those listed for essential spares to maintain the plant in an operational condition.

These shall be subject to agreement between the Contractor and the Employer and shall be based on manufacturers’ recommendations.


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6.10.3.1 Generator Circuit Breaker Scheme (GCB)

(a) The Contractor shall list in the pricing schedule of the Contract the individual prices of the spare parts (if any) together with the prices of all other spare parts that the manufacturer recommends should be held. Unit prices should be stated and the price given shall be valid for any reasonable quantity required under the Contract by the Employer.

(b) the Employer may order all or any number of the parts at it’s discretion. The Contractor shall supply the parts selected at the individual prices stated in the schedule.

(c) All parts ordered shall be interchangeable and suitable for use in place of corresponding parts supplied with the plant. They shall comply with the Specification and shall be suitably marked or numbered for identification and prepared for storage in an approved manner to prevent deterioration. Packing and identification of spare parts shall be in accordance with the requirements of this Specification.

6.10.4 Special and Maintenance Tools

The Contractor shall list in Volume 12 Technical Schedules those tools and appliances which are essential for the maintenance of the plant and the additional tools and appliances which it is recommended should also be purchased.

Tools for maintenance of the generator and the auxiliaries shall be provided as follows:

6.10.4.1 Generator

One (1) apparatus, to maintain a breathable atmosphere inside the generator during personnel access via manholes, and to prevent the condensation of moisture within the generator when the generator is de-gassed but not otherwise open to atmosphere.

A description of the proposed apparatus shall be included.

6.10.4.2 Generator Circuit Breaker Scheme (GCB):

(a) One complete set of all special spanners, tools and appliances including special slings and lifting equipment necessary for maintaining the whole of the Plant including that Plant supplied by Subcontractors, shall be provided. The spanners and tools supplied under this Clause shall be new and shall not be used during the erection of the Plant. A list of such spanners, tools and appliances shall be given in the appropriate schedule.

(b) The spanners shall include two spanners to fit the nuts of all bolts 25mm diameter and over. Grease guns, spanners and tools which are of a size and type which could be reasonably expected to be readily available to tradesmen are not required to be provided under this Clause.

6.10.5 Consumables

The Contractor shall supply consumables required for the equipment and systems being provided under the Contract in accordance with Volume 2 and as generally listed below.

The Contractor shall list the consumables in Volume 12 Technical Schedules.


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The Contractor shall add to these list consumables which it is considered should also be purchased to maintain the plant in an operational condition.

6.10.5.1 High Voltage Switchyard system

No. Item Qty

(a) Insulation oil - litres 1000

(b) SF6 gas - 42 kg cylinder full 1

(c) SF6 gas cylinder - 42 kg empty 1

(d) Seals - sets 2

(e) Grease - each type, litres 10

(f) Lubricating oil - each type, litres 100

(g) Fuse cartridges - each type 10

(h) Lamps - each type 10

6.10.5.2 Generator Circuit Breaker Scheme (GCB):

Consumable spares which will require replacement at intervals of less than 24 months, shall be provided as part of the Contract and the price included in the total contract price. The consumable spares shall be sufficient for one year's normal usage. Where an item is not listed in the appropriate schedule and requires replacement in less than 24 months from the date of Provisional Acceptance, the consumable spares shall be provided by the Contractor at no additional cost to the Employer.


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APPENDICES

APPENDIX 1: SPECIALIZED REPORT ON THE COMMUNICATION SYSTEM FOR THAI BINH TPP PROJECT 2 X300 MW

CHAPTER 1: GENERAL

1.1 Basis

Specialized report on agreement for arrangement of communication system for Thai Binh TPP project was prepared based on the following grounds:

- Requirements for integrating SCADA/EMS system of Load dispatch centres and connection for protecting 220kV transmission lines.

- Letter No 3396/CV-EVN-KTLĐ, dated August 07, 2002, EVN supplied firm guidance in “Works relating to SCADA/EMS system”.

- Letter No 581/ĐĐQG-CN, dated August 04, 2009 issued by the National Load Dispatch Center A0 on “Requirement on type of modem for Load Dispatch Center”.

- Investment Project Report for “Thai Binh thermal power plant” prepared by PECC1.

1.2 Requirements of communication system

1.2.1 For Control – Dispatch system

Thai Binh thermal power plant (Thai Binh TPP) will be equipped with an RTU system and pursuant to Article 7 of the regulation “Constructing and Managing the operation of SCADA equipments of substation and power station”, code QĐ 09-04 (issued together with Decision No 1208/QĐ-EVN, dated July 29, 2008) of Vietnam Electricity, Thai Binh TPP shall be controlled and supervised by National Load Dispatch Center (A0) and Northern Region Load Dispatch Center (A1).

Therefore the communication system in this project shall ensure sufficient channels for providing the following services:

- Supplying Hot-line telephone channels between Thai Binh TPP and A0, A1.

- Supplying data transmission channels for SCADA/EMS system: supplying communication channel for implementing SCADA functions of Thai Binh TPP from A0, A1.

1.2.2 Communication channel for transmission line protection relay.

Protection relay system shall provide sufficient protection signal transmission communication channels for two 220kV transmission lines from 220kV switchyard of Thai Binh TPP to Thai Binh 220kV substation. Protection signals required for exchange for each transmission line include:

- Protection circuit 1: Differential protection, directional earth – fault protection and inter-tripping signal.

- Protection circuit 2: Distance protection, directional earth – fault protection and inter-tripping signal.


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1.2.3 Connecting PABX at Thai Binh TPP to Power sector switchboards.

Establishing 4W E&M trunking lines, E1 trunking line connecting switchboard at Thai Binh TPP to other switchboards in Power sectors for telephone, fax, data communication between subscribers in Power sector and with other subscribers through automatic dialing.

Providing the service of data transmission of electric power metering system for Power purchasing.

1.2.4 Available lines for connecting LAN/WAN

Supplying Ethernet gate on SDH and PCM-30 equipments at Thai Binh TPP for being available lines for connecting LAN of Thai Binh TPP to power sector WAN.

1.3 Relevant Project.

1.3.1 Project “ Thai Binh 220kV transmission line – Thai Binh TPP and section extension at Thai Binh 220kV station”

This project is in technical design period, it has been considered for investment as follows:

- Providing 01 SDH/STM-4 optic transmission equipment at Thai Binh 220kV substation to connect Kim Dong 220kV substation and Thai Binh TPP.

- Providing 01 PCM-30 channel multiplexing equipment, 05 Teleprotection equipment units at Thai Binh 220kV substation, 01 PCM-30 channel multiplexing equipment, 02 Teleprotection equipment units at Kim Dong 220kV substation for transmitting signal to protection relays of 220kV Thai Binh – Kim Đong, Thai Binh – Thai Binh TPP transmission line.

- Providing 01 PCM-30 channel multiplexing equipment at VT1, 01 modem at A0, 01 modem at A1 for transmitting signals of SCADA/EMS, hotline between Thai Binh TPP and A0, A1.

- Providing additionally 4W E&M trunk card at Thai Binh 220kV substation, E1 trunk at VT1 for connecting switchboard at Thai Binh TPP to switchboard network of Power sector.

- Providing DC-48V Power supply at Thai Binh 220kV substation.

1.3.2 Project “220kV Kim Dong – Thai Binh transmission line”

220kV Kim Dong – Thai Binh transmission line project shall be constructed as a double circuit line with a length of 50km from Kim Dong 220kV substation to Thai Binh 220kV substation and it is anticipated to hang one OPGW/24SM optical fibre line on this double circuit line.

1.3.3 Thuong Tin 220kV – Kim Dong transmission line.

220kV Kim Dong – Thuong Tin transmission line project ( synchronous with 220kV Kim Dong substation) of which technical design is prepared by IOE shall construct a double circuit line with a length of 26km from Kim Dong 220kV substation to Thuong Tin 500kV substation and it is anticipated to hang one OPGW/24SM optical fibre line on this double circuit line.

1.3.4 Project “Kim Dong 220kV Substation”

This project is in the period of technical design, it is considered to arrange optical communication route on OPGW cable- 220kV Thuong Tin - Kim Dong in order to transmit signal for 220kV Thuong Tin - Kim Dong transmission line protection relays, SCADA


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signals, hotline between Kim Dong 220kV substation and A1 as well as switchboard connection at Kim Dong 220kV substation with other switchboards in Power sector.

Details as follows:

Optical cable and accessories

- Provide NMOC cable and accessories at Kim Dong 220kV substation and Thuong Tin 500kV substation for optical connection of Kim Dong – Thuong Tin.

Equipment

- Provide 01 SDH/STM-4 optic transmission equipment, ADM configuration at Kim Dong 220kV substation, supplementing STM-4/L4.2 optical card to hiT7070 equipment at Thuong Tin 500kV substation.

- Provide PCM-30 channel multiplexing equipment, communication equipment for protection relay at Kim Dong 220kV substation, Thuong Tin 500kV substation for protection of Thuong Tin - Kim Dong 220kV transmission line and transmission of SCADA/EMS signal, hotline from Kim Dong to A1.

- Provide DC-48V system: rectifier, charger, battery, power distribution cabinet at Kim Dong 220kV substation.


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CHAPTER 2: COMMUNICATION SYSTEM ARRANGEMENT

2.1 Transmission arrangement

2.1.1 Arrangement of optical transmission route.

The arrangement of the optical communication route from 220kV Thai Binh switchyard to Thai Binh 220kV substation will provide communication channels for 220kV transmission line Thai Binh TPP, Thai Binh 220kV substation protection relay system and incorporate communication channels for SCADA system from A0, A1 to Thai Binh TPP.

The arrangement of the optical communication route on NMOC cable: 220kV Thai Binh switchyard– Thai Binh TPP Centre Control Building:

- Provide NMOC/12SM optical cable for connection of 220kV switchyard – Centre Control Building with distance of 500m

- Provide for transmission channel capacity between the 220kV switchyard and the Thai Binh TPP Centre Control Building optical communication route at a bandwidth of STM-1 (Equivalent to speed of 155.52Mbps).

- The function of this communication route is to be a communication line connecting hotline system to A0, A1 and PABX room located in Centre Control Building to the Power sector communication network via forwarding at 220kV Thai Binh switchyard.

2.1.2 Communication channels arrangement.

2.1.2.1 Communication channel for control - supervision signals for Thai Binh TPP

Thai Binh TPP will be equipped with an RTU system at the 220kVswichyard. Signals from the SCADA/EMS system at the Plant and switchyard will be transmitted to the RTU and sent to A0, A1 by connection between the RTU at the Plant and preprocess computer (Front-End) at A0 and A1, using communication protocol IEC 60870-5-101.

Communication channels between the RTU and PCU will use a V24/RS-232 connection of the multiplexing equipment PCM-30. Signals from the RTU will be transferred through a modem to change into communication signals according to ITU-T V24 standard.

Thai Binh TPP will be controlled directly from A0, A1 through hotline telephone, using 2W channel of PCM-30 channel multiplexing equipment.

2.1.2.2 Communication channel for protection relay

The signal circuits of the No.1 protection relays (Differential protection, directional earth – fault protection and inter-tripping signal) will be transmitted directly through optical fibre of optical communication route 220kV Thai Binh TPP switchyard– Thai Binh 220kV station.

The signal of circuit of the No.2 protection relays (Distance protection, directional earth – fault protection and inter-tripping signal) will be transmitted via communication equipment from the protection relays (Teleprotection) and modified into a communication signal to be transmitted through the Digital E1(2Mbps) ITU-T G.703.6 channel of the optical transmission equipment SDH/STM-4 at the 220kV Thai Binh TPP switchyard – 220kV Thai Binh substation.

2.1.2.3 Channels connecting switchboards at Thai Binh TPP to Power sector switchboards:

- Additionally provide trunking card 4W E&M for the HICOM300 switchboard at 220kV Thai Binh substation to connect to the switchboard at Thai Binh TPP through


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optical transmission route: Centre Control Building –220kV Thai Binh switchyard – 220kV Thai Binh substation.

- Additionally provide trunking card E1 for the existing Flexible 6000 switchboard at Northern Telecommunication Center VT1 to connect with the switchboard at Thai Binh TPP through optical communication route: Centre Control Building – 220kV Thai Binh switchyard – 220kV Thai Binh substation and existing optical transmission routes of Power Sector.

- Provision of trunking card 4W E&M for the HICOM300 switchboard at 220kV Thai Binh substation and trunking card E1 for the Flexicom 6000 switchboard at VT1 is considered part of the project “220kV Thai Binh TPP transmission line– 220kV Thai Binh substation and extension of bay at 220kV Thai Binh substation ”.

2.1.2.4 LAN/WAN Connection

Provision of Ethernet gate on SDH and PCM-30 equipment at Thai Binh TPP to connect LAN of Thai Binh TPP to WAN of Power sector.

2.2 Transmission line calculation

The following parameters are used for calculation with wave length of 1310nm:

- Optical fibre : G.652

- Optical cable loss : 0,35dB/km

- Connecting loss : 0,5dB/connector

- Quantity : 2 connectors

- Joint Loss : 0,1dB/splice

- Average length of cable: 3km

- Optical flow loss : 1dB

- Reserve funds : 3dB

- Monochromatic dispersion: 3,5ps/nm.km

2.2.1 Thai Binh TPP 220kV switchyard – 220kV Thai Binh substation route

Distance: 30km

Transmission line loss 0.35 x 30km 10.5 dB

Joint loss 0.1 x30/3 1.0 dB

Connecting loss 2 x 0.5 1 dB

Optical flow loss 1 dB

Additional Losses 3 dB

Total 16.5 dB

Transmission line dispersion 30 x 3.5ps/nm.km 105 ps/nm


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2.2.2 Thai Binh TPP 220kV switchyard Centre Control Building

Distance: 0.5km

Transmission line loss 0.35 x 0.5km 0.175 dB

Joint loss 0.1 x 2 0.2 dB

Connecting loss 2 x 0.5 1 dB

Optical flow loss 1 dB

Additional Losses 3 dB

Total 5.375 dB

Transmission line dispersion 0.5 x 3.5ps/nm.km 1.75 ps/nm

Conclusion: From the above calculation results, based on optical interface criteria without using optical amplifier according to ITU-T G.957 and TCN 68-173:1998 standard, it is recommended to choose L-4.1 communication for Thai Binh TPP 220kV switchyard – 220kV Thai Binh Substation route and I-1.1 communication for 220kV switchyard – Thai Binh TPP Centre Control Building route.


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CHAPTER 3: CONTENT OF AGREEMENT

3.1 Usage of optical fibre, SDH equipment.

3.1.1 Optical fibre

According to decentralized administration of EVN, National Power Transmission (NPT) is tasked to manage and develop several optical fibre on the 500kV, 220kV transmission lines. For the Northern region, optical fibres on the transmission lines managed by NPT are assigned to Power transmission Company No 1 (TTĐ1) to manage and develop. Remaining optical fibres are managed by Power Telecommunication Company (EVN-Telecom).

Currently, NPT has planned investment for OPGW-220kV/24SM optical fibre route from 220kV Thai Binh switchyard to 220kV Thai Binh substation. Based on the actual situation and relevant projects, it is recommended that NPT should allow for usage of the optical fibre route via optical communication route OPGW-220kV/24SM 220kV Thai Binh switchyard– 220kV Thai Binh substation as follows:

- 04 fibres for connecting optical communication route STM-4 220kV Thai Binh switchyard – 220kV Thai Binh substation.

- 04 fibres for connecting differential protection relay at 220kV Thai Binh switchyard– 220kV Thai Binh substation.

3.1.2 Usage of SDH equipment.

- According to the calculation in item 2.2, the optical communication route from SDH/STM-4 220kV Thai Binh switchyard - 220kV Thai Binh substation uses optical interface L-4.1, therefore, it is recommended that NPT should invest in the optical transmission equipment SDH/STM-4 at 220kV Thai Binh substation with provision of 02 L-4.1 gates to connect to SDH/STM-4 equipment at 220kV Thai Binh switchyard provided in this project.

- Thai Binh TPP is responsible for investing in the SDH/STM-4 optical transmission equipment and relevant equipment inside the fence of the Plant to connect to the 220kV Thai Binh substation, NPT is recommended to consider the use of SDH equipment and connect relevant communication channels from 220kV Thai Binh substation to VT1, A0, A1.

- As many companies use the existing SDH transmission equipment, it is proposed that NPT should work with EVN to issue an agreement which additionally defines the equipment managed by NPT.

3.1.3 Communication channels required for supply.

Optical communication channel:

- Connecting STM-4/L-4.1 220kV Thai Binh switchyard – 220kV Thai Binh substation.

E1 communication channel for the following purpose:

- Connecting PCM-30 Thai Binh TPP Centre Control Building –220kV Thai Binh switchyard: 01 channel.

- 220kV Thai Binh transmission line distance protection relay - 220kV Thai Binh substation: 02 channels.

- Connecting switchboard at Thai Binh TPP to switchboard at VT1: 01 channel.


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Notes: E1 channel connecting via PCM-30 220kV Thai Binh switchyard- VT1 is considered as part of the project “220kV TPP Thai Binh transmission line– 220kV Thai Binh substation and extending bays at 220kV Thai Binh substation”

3.2 Scope of investment to install communication equipment.

Thai Binh TPP will invest in and install communication equipment inside the fence of the Plant, other telecommunication equipments for connecting Thai Binh TPP to the national grid will be invested in through the project “220kV Thai Binh TPP transmission line– 220kV Thai Binh substation and extending bays at 220kV Thai Binh substation”.

3.2.1 Communication equipment for this project at Thai Binh thermal power plant.

a. At Centre Control Building

Optical transmission equipment

- Providing 01 SDH/STM-1 optical transmission equipment, MUX 1+1 configuration to connect to 220kV Thai Binh switchyard.

Optical fibre and accessories

- Providing 01 optical fibre rack together with ODF+TB cable terminal box

Access equipment

- Providing 01 PCM-30 channel multiplexing equipment connecting to 220kV Thai Binh switchyard to draw odd channels for serving hotline signal transmission channel and switchboard trunk signal among Thai Binh TPP.

- Providing 02 hotline telephone lines to transmit signals to A0, A1.

DC-48V system

- Providing DC-48V system: rectifier, charger, battery, power distribution cabinet and connection accessories.

b. At 220kVswitchyard

Optical Cable and accessories

- Provide 800m of NMOC cable, 12SM type (ITU-T G.652) together with flexible HDUPVC conduit for which 500m will be for connecting Thai Binh TPP Centre Control Building to the 220kV Thai Binh switchyard, 300m for connecting OPGW optical cable from the tower gantry beam (220kV Thai Binh substation bay) to ODF rack located in the communication room of the 220kV Thai Binh switchyard.

- Provide 01 OPGW-NMOC cable connecting box.

- Provide 02 optical fibre distribution racks together with ODF+TB cable terminal box

Access equipment

- Provide 01 PCM-30 channel multiplexing equipment connecting to the Centre Control Building of Thai Binh TPP and 220kV Thai Binh substation.

- Providing 02 sets of Teleprotection equipment for transmitting protection relay signals of Thai Binh TPP 220kV transmission line -Thai Binh 220kV substation


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3.2.2 Equipment and items recommended for NPT to invest in the project “220kV Thai Binh TPP transmission line– 220kV Thai Binh substation” for connecting Thai Binh TPP to the national grid.

a. 220kV Thai Binh substation

Optical transmission equipment

- Provide 01 SDH/STM-4 optical transmission equipment

Access Equipment

- Provide 01 PCM-30 channel multiplexing equipment

- Provide 02 sets of Teleprotection equipment for transmitting protection relay signals of Thai Binh TPP 220kV transmission line -Thai Binh 220kV substation

- Provide trunking card 4W E&M switchboard for the existing HICOM300.

Power supply

- Provide 01 DC-48V system

b. VT1/EVN Telecom

Access equipment

- Provide 01 PCM-30 channel multiplexing equipment together with cabinet and accessories.

DC-48V supply equipment

- Using existing DC-48V at VT1

c. National Load Dispatch Center A0

- Provide 01 modem at A0 for transmitting control-dispatch signals to Thai Binh TPP.

- Use the existing DC-48V power system at A0 to supply power to the modem.

- Communication cabling from 2W interface of PCM-30 (to Thai Binh TPP 220kV switchyard) to telephone at A0.

Northern Regional Load Dispatch Center A1

- Provide 01 modem at A1 for transmitting control-dispatch signals to Thai Binh TPP.

- Use the existing DC-48V power system at A0 to supply power to the modem.

- Communication cabling from 2W interface of PCM-30 (to Thai Binh TPP 220kV switchyard) to telephone at A1.

Notes:

- Agreement and connection works with entities such as EVN Telecom, Power Transmission company No 1, A0, A1… for allowing to install, use equipment and providing channel, transmission line for connecting Thai Binh TPP to the national grid are recommended NPT to implement via project “Thai Binh TPP 220kV transmission line – Thai Binh 220kV substation line and extending bay at Thai Binh 220kV substation”.

- PCM-30 and Teleprotection equipment provided by Thai Binh TPP at Thai Binh TPP (220kV switchyard, Centre Control Building) and equipment provided by NPT at Thai Binh 220kV substation, VT1 shall be compatible.


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CHAPTER 4: LIST OF COMMUNICATION EQUIPMENT AND MATERIALS

TO BE PROVIDED IN THIS PROJECT

No Name of equipment, material

Specification requirement Unit Quantity Notes

1 STM-4 Optical transmission equipment

- Standard: ITU-T, ETSI

- In Compliance with the regulations of CORBA, Multiservice Switching Forum.

- Connecting to STM-4 equipment at 220kV Thai Binh substation equipped by NPT by L-4.1 interface

- Connecting to STM-4 equipment at Thai Binh 2 TPP 220kV switchyard and STM-1 equipment at Centre Control Building of Thai Binh TPP by I-1 interface.

Set 01 Installed at Thai Binh TPP 220kV switchyard

2 STM-1 Optical transmission equipment


- Complying with regulations of CORBA, Multiservice Switching Forum.

- Connecting to STM-4 equipment at Thai Binh TPP 220kV switchyard by I-1 interface.

Set 01 Installed in the Centre Control Building of Thai Binh TPP

3 ETSI 19” equipment cabinet Cabinet 03 Thai Binh TPP 220kV switchyard: 02

Centre Control Building of Thai Binh TPP: 01

4 MDF/DDF cable distribution support

- Block 2Mbit/s (E1) : 63 gates

- Subscriber Block

(including lightening filter, power

Support 02 Installed at Thai Binh TPP 220kV switchyard and Centre Control Building of Thai Binh TPP.


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lightening protection for all gates): 200 pair

- Complete accessories yes

- Provided synchronous with STM-4, PCM-30 equipment.

5 NMOC nonmetallic optical cable

- Standard: IEC, IEEE, ITU-T

- Optical fibre : ITU-T G.652

- Number of Optical fibre : 12 fibres

m 800 Connecting 220kV switchyard to Centre Control Building of Thai Binh TPP: 500m

Connecting from the entrance tower to telecommunication room of 220kV switchyard

6 HDPE twisting plastic pipe m 800 - NMOC optical cable protection

7 PCM-30 channel multiplexing equipment


- Configuration : Drop-Insert

- Communication at transmission line: E1

- Communication at terminal: 30 channels

Nx64Kbps/G.703 (N 1)

Nx64Kbps/V24/V35/V36 (N 1)

V.35/ 64Kbps

Nx64Kbps/X.21/RS-530

2/4W E&M

2W VF FXO, FXS

To be compatible with PCM-30 equipped by NPT at 220kV Thai Binh substation and VT1

Set 02 - 220kV switchyard : 01

- Centre Control Building of Thai Binh TPP: 01

8 Teleprotection

- Standard:

IEC-60834-1 (10/1999), IEC-60870-2

ITU-T G.703.1; G.703.6

- Number of transmit commands:

Set 02 220kVswitchyard Thai Binh TPP: 220kV


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3 commands

- Transmission time : 10ms

To be compatible with Teleprotection equipped by NPT at 220kV Thai Binh substation

9 Modem

SCADA/EMS signal transmission between Thai Binh TPP and A0, A1

To be compatible with existing modem at A0, A1

Set 02 Installed in the 220kV switchyard room: 02

10 DC-48V system:

- rectifier, charger

- Battery set

- lightening filter, lightening protection.

System 02 Installed in the Centre Control Building of Thai Binh TPP and 220kV switchyard.

11 Accessories and materials for connection

System 01


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CHAPTER 5: DRAWINGS

See Volume 9 – Bidding Drawing


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APPENDIX 2: SPECIALIZED REPORT ON SCADA SYSTEM OF THAI BINH TPP PROJECT

ATTACHMENTS:

1. IEC-60870-5-101 Protocol information to A0

2. IEC-60870-5-101 Protocol information to A1

3. List of SCADA signals

4. SCADA Commissioning Tests


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CHAPTER I - GENERAL

1.1 The legal basis:

- The process of National Load Dispatch Center, number QTDD-11-2001, issued by Decision No. 56/2001/QD-BCN on 26/11/2001 by the Ministry of Industry.

- Official Letter No. 3396/CV-EVN-KTLD dated August 07, 2002 of Electricity of Vietnam on directing implementation of connecting SCADA / EMS system to the electrical system.

- Document No. 1325/CV-EVN-KTLD dated March 29, 2004 of Electricity of Vietnam on regulation for energizing for acceptance of the power plant and substation for item of checking switching operating remotely via SCADA system of Regional Load Dispatch Center and the National Load Dispatch Center .

- Document No. 6872/CV-EVN-KTLD-DDQG dated December 24, 2007 issued by Vietnam Electricity on requiring SCADA connection for operation of electrical system.

- Regulation for construction and operational management of the SCADA equipment of substations and power plants, issued together with Decision No. 1208/QD-EVN, dated July 28, 2008 of Vietnam Electricity.

- Document No. 1301/NPT-KT, dated 27/05/2009 of the National Transmission Corporation on the implementation of SCADA item, SCADA agreement and measuring for investment, improve and upgrade, expand the substation projects.

- Circular No. 12/2010/TT-BCT of the Ministry of Industry and Trade on regulating transmission system, issued on 15/4/2010.

1.2. Preliminary description for Thai Binh TPP

Thai Binh TPP is built at My Loc commune, Thai Thuy District, Thai Binh Province, left bank of the Tra Ly River with total capacity 2x300MW

Thai Binh TPP’s scope of work consists of the TPP and 220kV switchyard.

1.3. Scope of implementation:

The elements of the Thai Binh TPP shall be considered for controlling, monitoring from SCADA system as follows:

Elements of the plant include:

- Two (02) sets of generator-transformer: G1-GT1 and G2- GT2. Each generator has a capacity of 300MW. Generator transformer has a ratio of 220/19kV.

- Two (02) unit transformers 19/6.6/6.6 kV

- 6.6 kV busbar

Elements of 220kV switchyard include:

- 08 modules for switchgear according to the busbar diagram 3 / 2 for sections:

02 sections for 220kV lines to 220kV Thai Binh substation

01 section for start-up transformer 225kV/6.6/6.6 kV T1


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02 sections to the plant (connecting with 02 sets of generator- transformer)

- 220kV Bus bar

The content of the work to be performed includes:

- Installation of equipment and materials for SCADA connection in Thai Binh TPP, National Load Dispatch Center (A0) and Northern Region Load Dispatch Center (A1)

- Testing equipment in Thai Binh TPP

- RTU configuration declaration

- Point to point connection test

- Testing connection with National Load Dispatch Center (A0)

- Testing connection with Northern Region Load Dispatch Center (A1)


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CHAPTER 2: SCADA CONNECTION

2.1. Solution for SCADA system

To implement SCADA functions for elements on 220kV switchyard side and in Thai Binh TPP, a RTU system will be considered to be equipped and placed in the control building of 220kV switchyard of Thai Binh TPP.

2.2. Communication protocols

The protocol used for connections between the SCADA system of Thai Binh TPP with the Load Dispatch Centres shall comply with the protocol IEC-60870-5-101 (Refer to Information Protocol in Attachment 1)

2.3. Information exchange between the plant and National Load Dispatch Center (A0) and Northern Region Load Dispatch Centre (A1)

Pursuant to the single line diagram of Investment Project, based on the requirements of the load dispatching operation, based on regulations for construction and equipment operation management of SCADA of substation and power plants issued together with decision No. 1208/QD-EVN dated July 28, 2008, requiring minimum signals exchanging between Thai Binh TPP and SCADA system as follows:

2.3.1. Northern Region Load Dispatch Center will perform the following functions:

a. Monitoring:

Northern Region Load Dispatch Center will monitor all electrical equipment of the switchyard such as transformers, circuit breakers, disconnectors, earthing switches.

Details are as follows:

Status signals:

- Circuit Breaker: “close / open"

- Disconnector: “close / open"

- Earthing switch: “close / open"

Warning, alarm signals, indication:

- The common signals such as AC, DC source failures; warning about communication systems, fire alarm ...

- Alarm signals when protections acting, failure of protector.

- The alarms, warnings and indicators of Local/Remote control mode of the switchyard.

The measurement signals:

- For busbar: voltage (kV), frequency (f)

- For transformer: voltage (kV), amperage (A), active power (MW), reactive power (MVAR) at different voltage levels of transformer, tapping of voltage regulator of transformer.

- For line feeder: voltage (kV), amperage (A), active power (MW), reactive power (MVAR).


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b. Control:

Northern Region Load Dispatch Center will control transformers, circuit breakers, disconnectors of 220kV switchyard and reactive power of unit generators of Thai Binh TPP. Details are as follows:

- The control signals "close/open" for circuit breakers, disconnectors.

- Adjust the increase/decrease of reactive power or setting the value to adjust reactive power of unit generators.

- Adjust the increase/decrease of transformer voltage.

2.3.2. National Load Dispatch Center will perform the following functions:

a. Supervision:

National Load Dispatch Center will supervise all electrical equipments in the plant and switchyard such as generators, transformers, circuit breakers, disconnectors, earthing switches.

Status signals:

- Generator: "Operation/no operation"

- Circuit Breaker: "close/open"

- Disconnector: "close/open"

- Earthing switch "close/open"

Alarm signal, warning, indication:

- Common signals such as AC or DC source failures; warning about communication systems, fire alarm ...

- Alarm signals when protection relays operate, failures of protections .

- The alarms, warnings and indicators of Local/Remote control mode of the plant.

Measurement signals:

- For busbar: voltage (kV)

- For line feeder: voltage (kV), amperage (A), active power (MW), reactive power (MVAR)

- For unit: active power (MW), reactive power (MVAR), terminal voltages (kV), high adjust limit (MW), Low adjust limit (MW)

- For transformer: voltage (kV), amperage (A), active power (MW), reactive power (MVAR) at different voltage levels of transformer, tapping of voltage regulator of transformer

- For the whole plant

Total active power of the plant (MW)

Total reactive power of the plant (MVAR)


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b. Control:

National Load Dispatch Center will control the transformers, circuit breakers, disconnectors of Thai Binh TPP.



- Signal control type "Increase/Decrease" or set the value to adjust the active power of the generators.

SCADA signal numbering to be discussed will be shown in the attachment.

2.4. Equipment requirements for SCADA

2.4.1. Channels for SCADA system

Data transmission Channel from the SCADA system of Thai Binh TPP to National Load Dispatch Center A0 and Northern Region Load Dispatch Center A1 is designed as follows:

- Thai Binh TPP – A0 : 01 channel

- Thai Binh TPP – A1 : 01 channel

Detailed specifications for data transmission channels mentioned in the “Specialized Report on the Communication System for Thai Binh TPP Project 2 x 300 MW” as per Appendix 1.

2.4.2. RTU system connected to the load dispatch centers

RTU System in control building of 220kV switchyard shall be equipped including:

- RTU centre cabinet including I /O card for input/output signals with back-up level for each signal of at least 20%.

- SIC cabinet including transducers, intermediate relay and control relay

- All accessories including clamps, signaling cable, cable labels, the core, laces, clad...

The service for SCADA connection, RTU connected to A0 and A1 will have four ports:

- 02 ports (one main, one standby) to connect to A0

- 02 ports (one main, one standby) to connect to A1

2.4.3. Modem for SCADA connection

To ensure connection from the RTU in control building of 220kV switchyard of Thai Binh TPP to National Load Dispatch Center A0 and Northern Region Load Dispatch Center A1, a modem will be provided in pairs, one at the switchyard control building and one at the Load Dispatch Centers.

The modems to be supplied are detailed in the special report on telecommunications system of Thai Binh TPP with the following specifications:

2.4.3.1. Modem for connection Thai Binh TPP - National Load Dispatch Center A0

Equipped at control building of 220kV switchyard:

- Modem Type: Telenetics Stand-Alone:

- Model: MIU 14.4L (4-Wire leased line modem)


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- Serial interface: RS232

- Power supply: 48-220V AC / DC

Equipped at A0:

- Modem Type: Myriad Modem Cards (expansion cards mounted on the existing board)

- Model: MD 14.4L (4-Wire leased line modem)

- LEDs: Power, DTR, TxD, RxD, MR, CD, PTS, CTS, RI

- Connection rate: 9600bps (in the range from 1200bps- 9600bps)

2.4.3.2. Modem for connection Thai Binh TPP - Northern Load Dispatch Center A1:

Use the same model type to equip the control building of 220kV switchyard and A1:

- Modem Type: Westermo

- Model: TD23 DC

- Serial interface: RS232

- Power supply: 36-55VDC

- Connection rate: 1200bps (in the range from 1200bps - 9600bps)


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ATTACHMENT 1. IEC-60870-5-101 PROTOCOL INFORMATION TO A0

I. Link and common address

For Thai Binh TPP gateway, both Link address and Common address of ASDU are set to the same value:

GATEWAY SYSTEM NLDC

THAI BINH TPP 1

II. IEC-60870-5-101 protocol functions

1. Format class FT 1.2

2. Network configuration

- Point-to-point

3. Physical layer

- Both control and monitor directions: Unbalanced interchange circuit. The baud rate is 1200, 2400, 4800 or 9600 bit/s depends on the configuration of transmission line.

4. Link layer

- Link transmission procedure: Unbalanced

- Address field of the link: 1 Octet

- Frame length: 255 maximum

5. Application layer

- Common address of ASDU: 1 Octet

- Information object address: 2 Octets

- Cause of transmission: 1 Octet

- Process information in monitor direction:

<1>:= Single-point information (M_SP_NA_1)

<3>:= Double-point information (M_DP_NA_1)

<30>:= Single-point information with time tag CP56Time2a (M_SP_TB_1)

<31>:= Double-point information with time tag CP56Time2a (M_DP_TB_1)

<9>:= Measured value, normalized value (M_ME_NA_1)

<13>:= Measured value, short floating point value (M_ME_NC_1)

With point information, ID type <1> and <3> are used on General Interrogation phase, ID type <30> and <31> are used on Spontaneous change (Note that the time tags should be CP56Time2a, i.e. full time).


224

With measured value, ID type <9> or type <13> is used on both General Interrogation phase and Spontaneous change. Tap position indicator and power export/import are considered as measured value ID type <9> or <13>.


<45>:= Single command (C_SC_NA_1)

<46>:= Double command (C_DC_NA_1)

For CB, DS

<47>:= Regulating step command (C_RC_NA_1)

For Transformer TAP control

<48>:= Set point command, normalized value (C_SE_NA_1)

For power generation set point control.

- System information in control direction:

(station specific parameter)

<100>:= Interrogation command (C_IC_NA_1)

Note that, control of ID type <46>, <47> are Select-Before-Operate (SBO). Control of ID type <48> are Direct-Operate (SBO).

III. IOA range

SIGNAL TYPE/SYSTEM NLDC

IOA

Single Digital Input 15000 to 24999

Double Digital Input 25000 to 42999

Analog Input 1 to 1999

Digital Output 43000 to 65535

Analog Output 2000 to 14999


225

ATTACHMENT 2. IEC-60870-5-101 PROTOCOL INFORMATION TO A1

I. Link and common address

For Thai Binh TPP gateway, both Link address and Common address of ASDU are set to the same value:

GATEWAY SYSTEM NRLDC

THAI BINH TPP 100

II. IEC-60870-5-101 protocol functions

1. Format class FT 1.2

2. Network configuration

- Point-to-point

3. Physical layer

- Both control and monitor directions: Unbalanced interchange circuit. The baud rate is 1200, 2400, 4800 or 9600 bit/s depending on the configuration of the transmission line.

4. Link layer

- Link transmission procedure: Unbalanced

- Address field of the link: 1 Octet

- Frame length: 255 maximum

5. Application layer

- Common address of ASDU: 1 Octet

- Information object address: 2 Octets

- Cause of transmission: 1 Octet


<1>:= Single-point information (M_SP_NA_1)

<3>:= Double-point information (M_DP_NA_1)

<30>:= Single-point information with time tag CP56Time2a (M_SP_TB_1)

<31>:= Double-point information with time tag CP56Time2a (M_DP_TB_1)

<9>:= Measured value, normalized value (M_ME_NA_1)

<13>:= Measured value, short floating point value (M_ME_NC_1)

With point information, ID type <1> and <3> are used on General Interrogation phase, ID type <30> and <31> are used on Spontaneous change (Note that the time tags should be CP56Time2a, i.e. full time).


226

With measured value, ID type <9> or type <13> is used on both General Interrogation phase and Spontaneous change. Tap position indicator and power export/import are considered as measured value ID type <9> or <13>.


<45>:= Single command (C_SC_NA_1)

<46>:= Double command (C_DC_NA_1)

For CB, DS

<47>:= Regulating step command (C_RC_NA_1)

For Transformer TAP control

<48>:= Set point command, normalized value (C_SE_NA_1)

For power generation set point control.

- System information in control direction:

(station specific parameter)

<100>:= Interrogation command (C_IC_NA_1)

Note that, control of ID type <46>, <47> are Select-Before-Operate (SBO). Control of ID type <48> are Direct-Operate (SBO).

III. IOA range

SIGNAL TYPE/SYSTEM NRLDC

IOA

Single Digital Input 15000 to 24999

Double Digital Input 25000 to 42999

Analog Input 1 to 1999

Digital Output 43000 to 65535

Analog Output 2000 to 14999


227

ATTACHMENT 3: LIST OF SCADA SIGNALS

TYPE No CATEGORY STATE MEANING SIGNAL NAME

S/S

CO

MM

ON

GE

NE

RA

TO

R (

at te

rmin

al)

BU

SB

AR

LIN

E F

EE

DE

R

TR

AN

SF

. H.V

OL

TA

GE

SID

E

TR

AN

SF

. M. V

OL

TA

GE

SID

E

TR

AN

SF

OR

ME

R

TA

P C

HA

NG

ER

CIR

CU

IT B

RE

AK

ER

ISO

LA

TO

R

EA

RT

HIN

G I

SOL

AT

OR

INTERNAL RTU SIGNAL RTU FAULT X

DATA ACQUIRED FROM RTU

ATM

1 ANALOG F FREQUENCY - POWER PLANT / S/S 220kV) X

2 ANALOG A AMPERE X X X

3 ANALOG K V VOLTS X X X X

4 ANALOG M W MEGAWATTS X X X

5 ANALOG M X MEGAVARS X X X

6 ANALOG T P I TAP CHANGER X

7 ANALOG AGC-HIGH AGC-HIGH REGULATING LIMIT

8 ANALOG AGC-LOW AGC-LOW REGULATING LIMIT

TOTAL PER BAY :

ATM-Total


228

TSS-1B

1 HEALTH 1 ALARM DC SYSTEM 48V FAULT X



4 HEALTH 1 ALARM RECTIFIER 48V FAULT X

5 HEALTH 1 ALARM AC SYSTEM 220V/ 380V FAULT X

6 HEALTH 1 ALARM COMMUNICATION PLC FAULT X

7 HEALTH 1 ALARM COMMUNICATION OPTICAL/RADIO/MICROWAVE FAULT X

8 HEALTH 1 ALARM FIRE ALARM (When applicable) X

9 HEALTH 1 ALARM SWITCHING EQUIPMENT NOT READY (AIR / OIL / SF6 / MECHANICAL)

X X W

10 HEALTH 1 ALARM EQUIPMENT FAULT X X

11 PROTECTION 1 OPERATED BUSBAR PROTECTION - MAIN X

12 PROTECTION 1 OPERATED BUSBAR PROTECTION - BACKUP (when applicable) X

13 PROTECTION 1 OPERATED BREAKER FAILURE PROTECTION X X

14 PROTECTION 1 OPERATED OVERVOLTAGE (OVERFLUXING FOR GENERATOR TRANSFORMER) X X(*)

15 PROTECTION 1 OPERATED UNDERVOLTAGE PROTECTION X

16 PROTECTION 1 OPERATED LINE DISTANCE PROTECTION ZONE 1 X



19 PROTECTION 1 OPERATED LINE DIFFERENTIAL PROTECTION X

20 PROTECTION 1 OPERATED DIRECTIONAL OVERCURRENT PROTECTION (67/67N) X X

21 PROTECTION 1 OPERATED OVER CURRENT PROTECTION (50/51) X X X

22 PROTECTION 1 OPERATED EARTHFAULT OVER CURRENT PROTECTION (50/51N) X X X

23 PROTECTION 1 OPERATED INTERTRIP-SENT X

24 PROTECTION 1 OPERATED INTERTRIP-RECEIVED X


229

25 PROTECTION 1 OPERATED AUTORECLOSE ORDER X X

26 PROTECTION 1 OPERATED TRANSFO. OVERLOAD PROTECTION ALARM X

27 PROTECTION 1 OPERATED TRANSFO. OVERLOAD PROTECTION TRIP X

28 PROTECTION 1 OPERATED EQUIPMENT (VOLTAGE) UNBALANCE PROTECTION W

29 PROTECTION 1 OPERATED EQUIPMENT DIFF. PROTECTION DIFFERENTIAL STAGE

30 PROTECTION 1 OPERATED TRANSFO. DIFFERENTIAL PROTECTION - MAIN X

31 PROTECTION 1 OPERATED TRANSFO. DIFFERENTIAL PROTECTION - BACKUP X

32 PROTECTION 1 OPERATED RESTRICTED EARTH FAULT PROTECTION X

33 PROTECTION 1 OPERATED TRANSFO. BUCCHOLZ X

34 PROTECTION 1 OPERATED TRANSFO. BUCCHOLZ X

35 PROTECTION 1 OPERATED PRESSURE RELIEF RELAY X X

36 PROTECTION 1 OPERATED OIL TEMPERATURE PROTECTION TRIP X X

37 PROTECTION 1 OPERATED OIL TEMPERATURE PROTECTION ALARM X

38 PROTECTION 1 OPERATED WINDING TEMPERATURE PROTECTION TRIP X

39 PROTECTION 1 OPERATED WINDING TEMPERATURE PROTECTION ALARM X

40 PROTECTION 1 OPERATED EQUIPMENT TRIP X X X

41 INFORMATION 1 LOCAL OPERATIOIN MODE REMOTE/LOCAL X X X X X X W

42 INFORMATION 1 DISABLE RTU REMOTE CONTROL X

TOTAL PER BAY :

TSS - TOTAL :

TSS-2B 1 INFORMATION 10/01 OPEN / CLOSE SWITCHING EQUIPMENT STATUS X X X X

RCS-2B

1 TELECONTROL 1+1 OPEN / CLOSE SWITCHING EQUIPMENT CONTROL X X W

2 TELECONTROL 1+1 OR SETPOINT

RAISE / LOWER TAP CHANGER CONTROL X


230

3 TELECONTROL 1+1 OR SETPOINT

ACTIVE POWER INCREASE/DECREASE

GENERATOR ACTIVE POWER CONTROL X

TOTAL PER BAY :

RCS - TOTAL :

Note:

W Where applicable

* Apply for generator transformers only

X Latest modification


231

Attachment 4. SCADA Commissioning Tests

No

Test Scope Unit Quantity

I Connecting test from Thai Binh TPP to National Load Dispatch Center A0 (End - to - End)

1 Measurement signal (Analog Input):

Plant:

02 Generator Transformers GT1, GT2: 08 signals for each Transformer measuring: U, I, P, Q at 220kV side

Two Generators G1, G2: 12 signals, each Generator measuring:

- U, I, P, Q (terminals)

- P high limit (MW)

- P low limit (MW)

6.6 kV Busbar 1A, 1B, 2A, 2B, 0A, 0B: 06 signals, each Busbar section measuring 01 voltage signal U

Total capacity of the whole plant: 02 signals

- Total Active Power (P total) of the plant

- Total Reactive Power (Q total) of the plant

220kV switchyard:

02 (two) 220kV line sections : 08 signals, each section measuring: U, I, P, Q.

02 (two) 220kV Busbars TC1 and TC2: 04 signals

Each Busbar measuring frequency (f) and voltage (U)

Transformer T1: 13 signals, each Transformer measuring:

- U, I, P, Q for the 220kV side

- U, I, P, Q for the 6.6 kV side

- The position of the step of the voltage regulator

Signal 53

2 Warning signal (Single Input):

Signal for the whole plant including 07 signals:

- 01 signal to administration control SCADA / Substation

- 01 fire alarm signal

- 01 alarm signal for failure of 48V DC power source

Signal 178


232

- 01 alarm signal for failure of 220V DC power source

- 01 alarm signal for failure of AC 220/400V power source

- 01 failure signal of information equipment

- 01 failure signal in the RTU system

Plant:

02 sections of Generator Transformers GT1, GT2: 24 signals

Each section of Generator Transformer including:

- 02 Differential protection signals of Transformer for tripping

- 01 Earth Fault protection signal inside Transformer for tripping

- 01 Over Current protection signal for tripping

- 01 Over Load protection alarm signal

- 01 level 1 Buchholz protection signal for alarming

- 01 level 2 Buchholz protection signal for tripping

- 01 protection signal of Transformer pressure for tripping

- 01 Oil temperature protection signal for tripping

- 01 Winding temperature protection signal for tripping

- 01 protection failure relay signal

- 01 signal for administration of Local / Remote

02 sections of Generators G1 and G2: 34 signals

Each section including:

- 01 Differential protection signal of Generator for tripping

- 01 Differential protection signal of excitation Transformer for tripping

- 01 Stator Earth Fault protection signal for tripping

- 01 protection signal of Rotor Earth Fault at one point.

- 01 protection signal of Rotor Earth Fault at two points for tripping

- 01 Over Current protection signal for tripping

- 01 Over Voltage protection signal for tripping

- 02 Over Load protection signals for tripping

- 01 Over Excitation protection signal for tripping

- 01 Loss of Excitation protection signal for tripping

- 01 Reverse Power protection signal


233

- 01 Negative-sequence Over Current protection signal

- 01 protection relay failure signal

- 01 signal Local / Remote

- 01 Generator failure signal

- 01 Generator trip signal

02 sections of unit Transformer (19/6.6/6.6 kV): 28 signals

Each Transformer including:


- 02 Earth Fault protection signals inside Transformer for tripping

- 03 Overcurrent protection signals for tripping

- 01 Over Load protection alarm signal



- 01 protection signal of Transformer Over Pressure for tripping




220kV switchyard:

02 sections for 220kV line to Thai Binh: 22 signals

Each section consists of 11 signals:

- 01 Differential protection signal for tripping

- 01 level 1 Distance protection signal for tripping



- 01 Directional Overcurrent protection signal for tripping (67)

- 01 Directional Earth Fault Overcurrent protection signal for tripping(67N)

- 01 Instantaneous Overcurrent protection signal for tripping (50)

- 01 IDMT Overcurrent protection signal for tripping (51)

- 01 Differential protection signal of Busbar for tripping

- 01 auto reclose relay signal



234

08 modules 220kV Circuit Breaker: 40 signals

Each module consists of 05 signals:

- 01 Circuit Breaker failure protection signal for tripping

- 01 SF6 low gas signal

- 01 unavailable Circuit Breaker signal


- 01 lock position signal Local/Remote

Transformer T1 including 21 Signals



- 01 Differential protection signal for Busbar


- 01 Directional Earth Fault Overcurrent protection signal for tripping (67N)

- 03 Instantaneous Overcurrent protection signals for tripping (50)

- 03 IDMT Overcurrent protection signals for tripping (51)

- 01 Transformer overload protection signal



- 01 OLTC pressure protection signal for tripping

- 01 Transformer over pressure protection signal for tripping




- 01 signal Local/Remote

220kV Busbar including 02 signals

- 01 Busbar protection signal for tripping

- 01 protection failure signal

3 Status Signal of Disconnectors, Circuit Breakers, Earthing blades (Double Input)

Plant

02 sections 19/6.6/6.6 kV Unit Transformer: 04 signals, each section

Signal 55


235

including:

- 02 Circuit Breaker signals close/open

02 Generator terminals Circuit Breakers : 02 Circuit Breaker signals close/open

220kV switchyard

02 sections of 220kV line : 06 signals each section of the line including:

- 01 Disconnector signal

- 02 Earthing blade signal

08 220kV Circuit Breaker modules : 40 signals

Each module includes:

- 01 Circuit Breaker signal

- 02 Disconnector signals

- 02 Earthing blade signals

01 section of T2 Transformer : 03 signals

Each section includes:



4 Control signal for Generator, Circuit Breaker (Double Output)

Plant

02 Generators G1, G2: 08 signals, each Generator including:

- 02 speed signals of increase capacity AGC High/Low

- 01 signal of increase/decrease Active Power P

02 Generator terminals Circuit Breakers : 02 signals each Circuit Breaker including:

- 01 signal open / close

Signal 9

No

Test Scope Unit Quantity

II Connecting test from 220kV switchyard to the Northern Region Load Dispatch Center A1 (End - to - End)

1 Setting database for measuring signal (Analog Input): Signal 25


236

220kV switchyard:

02 sections 220kV line: 08 signals, each section measuring: U, I, P, Q

02 (two) 220kV Busbars TC1 and TC2: 4 signals

Each Busbar measuring frequency f, voltage U

Transformer T1: 13 signals

- U, I, P, Q for the 220kV side

- U, I, P, Q for the 6.6 kV side

- Step position of the voltage regulator

2 Warning signal: (Single Input)

220kV switchyard:

Common Signal including 07 signals:

- 01 signal to administration control SCADA/Substation

- 01 fire alarm signal

- 01 alarm signal 48V DC

- 01 alarm signal 220V DC

- 01 alarm signal AC 220/400V

- 01 failure signal of information equipment

- 01 failure signal in the RTU system

02 sections for 220kV line to Thai Binh: 22 signals

Each section consists of 11 signals:

- 01 current Differential protection signal for tripping






- 01 Instantaneous Overcurrent protection signal for tripping (50)

- 01 IDMT Overcurrent protection signal for tripping (51)

- 01 Differential protection signal of Busbar for tripping

- 01 auto reclose relay signal

- 01 protection relay failure signal .

08 modules 220kV Circuit Breaker: 40 signals

Signal 92


237

Each module consists of 05 signals:

- 01 Circuit Breaker failure protection signal for tripping

- 01 SF6 low gas signal

- 01 unavailable Circuit Breaker signal

- 01 protection relay failure signal .

- 01 lock position signal Local / Remote

Transformer T1 including 21 Signals



- 01 Differential protection signal for Busbar



- 03 Instantaneous Overcurrent protection signals for tripping (50)

- 03 IDMT Overcurrent protection signals for tripping (51)

- 01 Transformer overload protection signal



- 01 OLTC pressure protection signal for tripping

- 01 Transformer Over Pressure protection signal for tripping




- 01 signal Local/ Remote

220kV bus bar including 02 signals

- 01 Busbar protection signal for tripping

- 01 protection failure signal

3 Status Signal of Disconnectors, Circuit Breakers, Earthing blades (Double Input)

220kV switchyard

02 sections 220kV line : 06 signals

each section of the line including:


Signal 49


238


08 220kV Circuit Breaker modules : 40 signals

Each module includes:




01 section T2 Transformer : 03 signals

Each section includes:



4 Control signal for Disconnectors, Circuit Breakers, Transformer (Double Output)

Plant

02 Generators G1, G2: 02 signals, each Generator including:

- 01 signal increase / decrease of reactive power

220kV switchyard

Two sections 220kV line: 02 signals

Each section of the line including:


08 220kV Circuit Breaker modules: 24 signals

Each section including:



1 section of T2 Transformer : 02 signals

Including:


- 01 signal Increase / Decrease voltage

Signal 30

III Connecting test (Point - to - point).

1 ANALOG INPUT (AI) Signal Signal 53

2 SINGLE INPUT (SI) signal Signal 178

3 DOUBLE INPUT (DI) signal Signal 55

4 DOUBLE OUTPUT (DO) signal Signal 39


239

IV RTU configuration declaration. Set 1

V Equipment Test

1 Transducer U, I, P, Q testing Set 10

2 Transducer U test Set 2

3 Intermediate relay test Set 188


240

APPENDIX 3: SPECIALIZED REPORT ON CONNECTION TO NATIONAL POWER GRID OF THAI BINH TTPP PROJECT

CHAPTER 1: THAI BINH POWER CENTRE CONNECTION ALTERNATIVE

Thai Binh Power Centre includes 2 Thermal Power Plants, with capacity of:

- Thai Binh Thermal Power Plant: 2×300 MW

- Thai Binh 2 Thermal Power Plant: 2×600 MW

Pursuant to Decision No 4409/QĐ-BCT dated August 20, 2010 of the Ministry of Industry and Trade on “Approval of plan of connecting Thai Binh Power Centre to the national grid”, Thai Binh Power Centre shall be connected to the national grid at a voltage level of 220kV. Constructing synchronous works connecting Thai Binh Power Centre to the national grid:

Substation:

- Tien Hai 220kV substation with capacity of 125MVA

- Truc Ninh 220kV substation with capacity of 2x250MVA (replacing Trinh Xuyen substation)

- Thai Thuy 220kV substation

220kV Transmission line:

- Thai Binh Power Centre – Thai Binh double circuit line with a length of 30km, 3x400mm2 conduct.

- Thai Binh Power Centre – Tien Hai – Truc Ninh double circuit line with a length of 68km, 2x400mm2 conduct.

- Double circuit line with a length of about 25km, 2x330mm2 conduct from Truc Ninh 220kV substation connecting to Ninh Binh-Nam Dinh line.

- Thai Binh– Kim Dong 220kV double circuit line with a length of about 47km, 3x330mm2 conduct.

- Thai Binh– Thai Thuy double circuit line with the length of about 20km

CHAPTER 2: LOCAL POWER NETWORK CONNECTING TO THAI BINH POWER CENTRE

The following substations and lines are around Thai Binh 1 Thermal Power Plant:

- Thai Binh 220kV substation with a capacity of 2×125MVA.

- Nam Dinh 220kV substation with a capacity of 2×125MVA.

- Ninh Binh 220kV substation with a capacity of 2×125MVA.

- Thai Binh-Dong Hoa 220kV transmission line


241

- Thai Binh– Nam Dinh – Ninh Binh 220kV transmission line

According to the national power development plan (Master Plan No 6), it is anticipated that the following works shall be implemented:

Increasing the capacity of the Substation:

- Thai Binh 220kV substation: up to 2015, the capacity of the substation will be increased to 2×250MVA.

- Nam Dinh 220kV substation: up to 2010, the capacity of the substation will be increased to 125 + 250MVA, up to 2020 the capacity of the substation will be increased to 2×250MVA.

- Ninh Binh 220kV substation: in 2010 the capacity of the substation will be increased to 125+250MVA.

Substations to be newly constructed:

- Bim Son 220kV substation: capacity of 1×125MVA (up to 2010), 2×125MVA (up to 2015).

- Truc Ninh (Trinh Xuyen) 220kV substation: capacity of 1×250MVA (up to 2015), 2×250MVA (up to 2020).

- Ninh Binh 2 220kV substation (replacing Ninh Binh 2 thermal power plant): capacity of 1×250MVA (up to 2020).

- Kim Dong 220kV substation: capacity of 1×250MVA (in 2010), up to 2015 the capacity shall be increased to 2×250MVA.

- 220kV Pho Cao substation: capacity of 1×250 (up to 2020).

- Hai Hau 220kV substation: capacity of 1×250 (up to 2020).

- Tien Hai 220kV substation: capacity of 1×250 (up to 2020).

Transmission lines to be newly constructed:

- Thai Binh- Nam Dinh - Ninh Binh second line.

- Pho Noi-Kim Dong 220kV transmission line (2010), Kim Dong-Thai Binh (up to 2015).

- Pha Lai-Thai Binh 220kV transmission line (2010).

The calculation and examination of alternative connections for Thai Binh Thermal power plant to the national grid is done based on the consideration of power generation alternative of large Power Centres in the region such as Nam Dinh Power Centre (1200MW in the period of 2016-2020 and 2400MW in the period of 2021-2025) and Hai Duong Power Centre (1200MW in the period of 2011-2015). These power centres directly affect the connection alternative of connecting Thai Binh thermal power plant to the national grid.

In which:

- Nam Dinh thermal power plant, capacity of 1200MW in the period of 2016-2020. With consideration to the period of 2021-2025 the capacity of Nam Dinh Power centre is 2400MW. Generating voltage level is 500kV (Nam Dinh 1 thermal power


242

plant) and 220kV (Nam Dinh thermal power plant. The power is mainly transmitted via Nam Dinh thermal power plant – Pho Noi 500kV transmission line. The 220kV side shall supply power to the regional 220kV substation: Bim Son 220kV substation, Ninh Binh 220kV substation and Ninh Binh 2 220kV substation.

- Hai Duong thermal power plant (1200MW) shall be connected to the national grid by 220kV voltage level, the power is transmitted via Hai Duong TPP– Gia Loc – Pho Noi, Hai Duong TPP – Pha Lai and Hai Duong TPP – Hai Duong 2 220kV transmission line.

CHAPTER 3: THE ONGOING POWER NETWORK WORKS ACCORDING TO THE PLAN

Thai Binh thermal power plant (Thai Binh TPP):

Works to be synchronous with Thai Binh TPP: AC3x400mm2 Thai Binh TPP – Thai Binh double circuit line has a length of 30km (according to Decision No 527B/QĐ-BCT dated September 29, 2008 on “Approval of Investment Project for construction of Thai Binh thermal power plant”).

The ongoing power network in the project area according to the master plan No VI:

- Thai Binh- Nam Dinh - Ninh Binh 220kV second line.

- Thai Binh– Kim Dong 220kV double circuit (to be implemented up to 2015).

- Thai Binh– Pha Lai 220kV single line.

CHAPTER 4. THAI BINH TPP SWITCHYARD

4.1 SCOPE OF CONNECTING SWITCHYARD

According to the Vietnam Power Network Master Plan as well as aforementioned power network calculation conditions and connection plan selection the 220kV switchyard of Thai Binh Power Centre shall be connected with the regional network under “Thai Binh Thermal Power Plant” project ( now changing name as “Thai Binh Thermal Power Plant” project following Decision No. 0823/BCT-NL dated January 20, 2010) and “Thai Binh 2 Thermal Power Plant” project approved by Ministry of Industry and Trade as follows:

- Two 220kV outgoing feeders to 220kV Thai Binh substation.

- Two 220kV outgoing feeders to Thai Binh TPP’s generators.

- One feeder to service the start-up supply for Thai Binh TPP.

- Two spare 220kV feeders for connection to Thai Binh 2 TPP’s generator transformer .

- One spare feeder to service the start-up supply for Thai Binh 2 TPP.

- Two 220kV outgoing feeders to 220kV Tien Hai substation

- Six 220kV spare feeders for connection to Thai Binh 2 TPP and development in the future


243

Through the results of calculation for connection alternatives Thai Binh TPP switchyard shall be connected with the national power network at a voltage level of 220kV and include the following feeders:

- Two 220kV outgoing feeders to 220kV Thai Binh substation.

- Two 220kV outgoing feeders to Thai Binh TPP’s generators.

- One feeder to service the start-up supply for Thai Binh TPP.

- One 220kV spare feeder for connection in the future

4.2 Main Technical solutions for the switchyard

4.2.1 Single line diagram

The 220kV switchyard of Thai Binh TPP shall operate under a 3/2 scheme complying with diagram of “Thai Binh Thermal Power Plant” project and “Thai Binh 2 Thermal Power Plant” project approved by Ministry of Industry and Trade.

The 220kV outgoing feeders will be equipped for Thai Binh TPP including 2 line sections, generator transformer bays and one start-up transformer bay which will be used for outdoor installation of circuit breakers, disconnectors, voltage transformers, current transformers ....

4.2.2 Equipment arrangement layout

The switchyard shall be designed as both outdoor and indoor. 220kV distribution equipment and transformer shall be located outdoor. Computer system, protection and control system, auxiliary systems and telecommunications shall be located indoors.

Thai Binh TPP 220kV Switchyard shall be constructed and operated independently from Thai Binh 2 TPP 220kV Switchyard. The operation of equipment of Thai Binh TPP 220kV Switchyard shall be carried out from the Centre Control Building of Thai Binh TPP 220kV Switchyard.

4.3 Solution for connecting primary part

4.3.1 Connection switchyard with the regional grid

4.3.1.1 Connection to Thai Binh 220 kV substation

Thai Binh TPP 220 kV switchyard to Thai Binh 220kV substation will be installed outdoors for both feeders. Thai Binh TPP 220kV double circuit transmission line AC3x400mm2 – Thai Binh 220kV substation will be connected from the transmission tower of the line to the gantry beam of the two feeders to Thai Binh of Thai Binh TPP 220 kV switchyard.

4.3.1.2 Connection to Thai Binh 2 TPP 220 kV switchyard

Thai Binh TPP 220 kV switchyard will be connected with Thai Binh 2 TPP 220 kV switchyard via a busbar circuit breaker section:

- In normal operation mode the busbar circuit breaker will be closed to support flexible capacity transmission between the two plants:

- In emergency mode the busbar circuit breakers will trip to reduce short circuit fault current and at the same time isolate the failure point with the other switchyard.


244

The busbar circuit breaker section will be equipped in Thai Binh TPP 2 area. The bus bar circuit breaker section between the two plants is also a very convenient location of the power metering for power purchasing.

4.3.2 Connection with Thai Binh TPP

4.3.2.1 The 220kV side

The 220kV switchyard will be connected with Thai Binh TPP via two 220kV feeders to the generator transformers and one 220kV feeder to the start- up transformer of Thai Binh TPP. At these feeders outdoor equipment such as circuit breakers, disconnectors, current transformers, voltage transformers ....will be installed. From the Thai Binh TPP switchyard a double circuit line ACSR500 connection to the high voltage terminals of the generator transformers in Thai Binh TPP will be built.

4.3.2.2 The 6.6 kV side

The 220kV outdoor equipment for the 44MVA- 220kV start-up transformer of the plant will be installed in the switchyard. The start-up source will supply electricity to the auxiliary system of the plant and start motors via the power cable system connections from the 6.6 kV side of the auxiliary transformer to the auxiliary system of the plant

4.4 Control and protection Solution

220kV switchyard components shall be equipped with control equipment & protection relays which are compatible with the control & protection system of Thai Binh TPP. The control equipment & protection relay shall be designed in compliance with the relevant Vietnamese standards, regulations of EVN and other popular international standards.

4.4.1 System control Solution

There are 4 levels of control and monitoring for 220kV switchyard:

- From the Northern Regional Load Dispatch Centre and National Load Dispatch Centre.

- From the Central Control Room of Thai Binh TPP

- From the Central Control Room of the 220kV switchyard (including two locations)

- Workstations of computerised control system.

- Back-up control cubicles.

- From the switching equipment (Circuit Breakers, disconnectors, etc).

The computerised control system and Remote Terminal Unit (RTU) for the 220kV switchyard shall be designed and integrated with the control and monitoring system of Thai Binh TPP. From the Central Control Room of the 220kV switchyard the main functions of the computerised control system for 220kV switchyard shall be:

- Closing/Opening of circuit breakers, disconnectors, motor controlled earthing switches with synchro-check and interlocking.

- Increasing/decreasing transformer voltage and transformer cooling system control.

- Position indication of circuit breakers, isolators, earthing switches and transformer tap changers.


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- Measurement of the main parameters A, V, W, VAR, Wh, VARh of transmission lines and every side of transformers as well as indication of oil temperature and winding temperature of transformers.

- Archiving and processing data, recording faults.

The backup for the computer system and backup control cubicle with logic hard wiring shall be equipped for 220kV switchyard.

4.4.2 Protection relay solution

In compliance with EVN regulations for protection of the 220kV switchyard equipment the adopted protection relays shall be digital relays with microprocessors and be capable of communicating with the computerised control and SCADA systems. The main solutions shall be considered and applied as follows:

a. 220kV transmission line:

Each line shall be equipped with two protection circuits. In each circuit the main protection shall be differential protection and distance protection. Backup protection shall include directional over current protection, overcurrent protection, etc. Auto-reclose with synchro-check functions shall be also installed.

Note: differential protection relays shall be equipped and compatible with the opposite ends

b. 220kV circuit breaker bay:

Each bay shall be equipped with breaker failure protection, busbar protection and synchro-check functions.

c. 225/6/6kV transformers:

Together with the buchholz relay, oil temperature relay, oil level relay, etc., each transformer shall be equipped with two protection circuits. In each protection circuit the main protection shall be differential protection. Back-up protection functions shall include directional over current protection, over current protection, etc. Auto voltage regulation shall also be installed.

d. 220kV busbars:

Differential protection shall be equipped with numerical distributed busbar protection.

4.5 SCADA system solution

Pursuant to the single line diagram of the Investment Project, based on the requirements of the load dispatching operation and based on the regulations for construction and equipment operation and management of SCADA of substations and power plants issued together with decision No. 1208/QD-EVN dated July 28, 2008 requiring minimum signal exchang between Thai Binh TPP and SCADA system as follows:

- Communication exchange between the plant and National Load Dispatch Centre (A0) and Northern Region Load Dispatch Centre (A1)

4.5.1 Northern Region Load Dispatch Centre will perform the following functions:

a. Monitoring:

Northern Region Load Dispatch Center will monitor all electrical equipment of the switchyard such as transformers, circuit breakers, disconnectors, earthing switches.


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Status signals:

- Circuit Breaker: “close / open"

- Disconnector: “close / open"

- Earthing switch: “close / open"

Warning, alarm signals, indication:

- The common signals such as AC, DC source failures; warning about communication systems, fire alarm ...

- Alarm signals when protections acting, failure of protector.

- The alarms, warnings and indicators of Local/Remote control mode of the switchyard.

The measurement signals:

- For busbar: voltage (kV), frequency (f)

- For transformer: voltage (kV), amperage (A), active power (MW), reactive power (MVAR) at different voltage levels of transformer, tapping of voltage regulator of transformer.

- For line feeder: voltage (kV), amperage (A), active power (MW), reactive power (MVAR).

b. Control:

Northern Region Load Dispatch Center will control transformers, circuit breakers, disconnectors of 220kV switchyard and reactive power of unit generators of Thai Binh TPP. Details are as follows:


- Adjust the increase/decrease of reactive power or setting the value to adjust reactive power of unit generators.

- Adjust the increase/decrease of transformer voltage.

4.5.2 National Load Dispatch Centre will perform the following functions:

a. Supervision:

National Load Dispatch Center will supervise all electrical equipments in the plant and switchyard such as generators, transformers, circuit breakers, disconnectors, earthing switches.

Status signals:

- Generator: "Operation/no operation"

- Circuit Breaker: "close/open"

- Disconnector: "close/open"

- Earthing switch "close/open"

Alarm signal, warning, indication:


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- Common signals such as AC or DC source failures; warning about communication systems, fire alarm ...

- Alarm signals when protection relays operate, failures of protections .

- The alarms, warnings and indicators of Local/Remote control mode of the plant.

Measurement signals:

- For busbar: voltage (kV)

- For line feeder: voltage (kV), amperage (A), active power (MW), reactive power (MVAR)

- For unit: active power (MW), reactive power (MVAR), terminal voltages (kV), high adjust limit (MW), Low adjust limit (MW)

- For transformer: voltage (kV), amperage (A), active power (MW), reactive power (MVAR) at different voltage levels of transformer, tapping of voltage regulator of transformer

- For the whole plant

Total active power of the plant (MW)

Total reactive power of the plant (MVAR)

b. Control:

National Load Dispatch Center will control the transformers, circuit breakers, disconnectors of Thai Binh TPP.



- Signal control type "Increase/Decrease" or set the value to adjust the active power of the generators.

4.6 Power metering system for power purchasing

4.6.1 Scale of the power metering:

To facilitate the purchase and sale of power between the plant and EVN a metering cubicle cabinet will be installed. Data collection and metering data services will be performed by the devices including:

- PC computer with software, power meters, modems, telephone subscribers, wiring boxes CT, VT and accessories ... From the PC at the plant or the meters the data from the meters will be transmitted to the communication Centre of EVN.

Pursuant to promulgated regulations the power metering system for power trading in Thai Binh TPP will be scaled as follows:

Main metering system located at:

- 02 points on the 220kV side of 02 transformers GT1, GT2


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- 01 point on the 220kV side of auxiliary transformer 225 / 6.6 / 6.6 kV T1

Standby metering system No.1 located at:

- 03 points adjacent to the metering point of the main metering system.


- Feeders for the 02 220 kV transmission lines to Thai Binh 220kV substation.

- 02 sections of the 220 kV (installed under Thai Binh 2 TPP project) N

4.6.2 Functions of power metering system

4.6.2.1 Main power metering system:

The main power metering system shall determine accurately and completely the measurable quantities of power trading as a basis for payment of power between Vietnam Electricity and Thai Binh TPP.

4.6.2.2 Standby metering system:

- Backup for the main metering system as a basis for calculating the quantity of power trading in the case where the main metering system is not working correctly or under failure.

- Supervise and cross check the results of the main metering system under normal operation of the main metering system.

- Combine with the main metering system and other standby metering systems to calculate power production capacity for payment in some special cases.

4.6.2.3 The requirements for the power metering system:

- Ensure sufficient supply of parameters and necessary data for the main metering system and standby metering systems to determine power for purchase / sale; to monitor operating condition, reliability of the metering system.

- Automatically record and store in the meters all the values and power index for both import and export at 24:00 hours on the last day of the billing period.

- Automatically collect metering data of main metering points and standby metering points.

- Metering data is collected automatically on computer for storage which is the basis for determining power purchasing / selling in the period.

- Automatic recording of quantities of active power at the identified metering points at a period every 30 minutes for both import and export of power.

- Power exchange data at metering points is collected daily, stored at Thai Binh TPP, then transmitted to the Communication Centre of EVN as a basis for management and system operation of the metering system and verifying the reliability of metering data.

4.6.3 Configuration of power metering system:

Configuration of power metering system in Thai Binh TPP shall include:

- Current transformers

- Voltage transformers


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- Connection boxes for power metering

- The power meters

- Metering circuits

- Metering cubicle

- Equipment for data collection and transmission of metering data

- Safety equipment, sealing position, seal

4.7 COMMUNICATION SYSTEM

4.7.1 Arrangement of optical transmission route.

The arrangement of the optical communication route from 220kV Thai Binh TPP to Thai Binh 220kV substation will provide communication channels for the 220kV transmission line Thai Binh TPP and Thai Binh 220kV substation protection relay system and incorporate communication channels for SCADA system from A0, A1 to Thai Binh TPP.

The arrangement of the optical communication route on NMOC cable between the 220kV Thai Binh switchyard and Thai Binh TPP Centre Control Building:

- Provide NMOC/12SM optical cable for connection of 220kV switchyard to the Centre Control Building with distance of 500m

- Provide for transmission channel capacity between the 220kV switchyard and the Thai Binh TPP Centre Control Building optical communication route at a bandwidth of STM-1 (Equivalent to speed of 155.52Mbps).

- The function of this communication route is to be a communication line connecting hotline system to A0, A1 and PABX room located in Centre Control Building to the Power sector communication network via forwarding at 220kV Thai Binh switchyard.

4.7.2 Communication channels arrangement.

4.7.2.1 Communication channel for control - supervision signals for Thai Binh TPP

Thai Binh TPP will be equipped with an RTU system at the 220kVswichyard. Signals from the SCADA/EMS system at the Plant and switchyard will be transmitted to the RTU and sent to A0, A1 by connection between the RTU at the Plant and preprocess computer (Front-End) at A0 and A1, using communication protocol IEC 60870-5-101.

Communication channels between the RTU and PCU will use a V24/RS-232 connection of the multiplexing equipment PCM-30. Signals from the RTU will be transferred through a modem to change into communication signals according to ITU-T V24 standard.

Thai Binh TPP will be controlled directly from A0, A1 through hotline telephone, using 2W channel of PCM-30 channel multiplexing equipment.

4.7.2.2 Communication channel for protection relay.

The signal circuits of the No.1 protection relays (Differential protection, directional earth – fault protection and inter-tripping signal) will be transmitted directly through optical fibre of optical communication route 220kV Thai Binh TPP switchyard– Thai Binh 220kV station.


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The signal of circuit of the No.2 protection relays (Distance protection, directional earth – fault protection and inter-tripping signal) will be transmitted via communication equipment from the protection relays (Teleprotection) and modified into a communication signal to be transmitted through the Digital E1(2Mbps) ITU-T G.703.6 channel of the optical transmission equipment SDH/STM-4 at the 220kV Thai Binh TPP switchyard – 220kV Thai Binh substation.

4.7.2.3 Channels connecting switchboards at Thai Binh TPP to Power sector switchboards:

Additionally provide trunking card 4W E&M for the HICOM300 switchboard at 220kV Thai Binh substation to connect to the switchboard at Thai Binh TPP through optical transmission route: Centre Control Building –220kV Thai Binh switchyard – 220kV Thai Binh substation.

Additionally provide trunking card E1 for the existing Flexible 6000 switchboard at Northern Telecommunication Center VT1 to connect with the switchboard at Thai Binh TPP through optical communication route: Centre Control Building – 220kV Thai Binh switchyard – 220kV Thai Binh substation and existing optical transmission routes of Power Sector.

Provision of trunking card 4W E&M for the HICOM300 switchboard at 220kV Thai Binh substation and trunking card E1 for the Flexicom 6000 switchboard at VT1 is considered part of the project “220kV Thai Binh TPP transmission line – 220kV Thai Binh substation and extension of bay at 220kV Thai Binh substation ”.

4.7.2.4 LAN/WAN Connection

Provision of Ethernet gate on SDH and PCM-30 equipment at Thai Binh TPP to connect LAN of Thai Binh TPP to WAN of Power sector.

5. CONCLUSION AND RECOMMENDATION

5.1. Conclusion.

After analyzing the calculation result of the connection alternative in Chapter 4 it can be concluded that the Thai Binh Power Centre connection alternative ensures the transmission t of power from Thai Binh Power Centre to the national grid.

5.2. Recommendation.

In order to safely and stably transmit power from Thai Binh Power Centre to the regional 220kV network it is recommended that:

Implement the works which are synchronous with Thai Binh 2 TPP:

- Truc Ninh 220kV substation (Trinh Xuyen): according to master plan No VI, Trinh Xuyen 220kV substation shall be constructed in the period of 2011-2015. It is recommended that the substation shall be constructed in Truc Ninh district, Nam Dinh province and changed into Truc Ninh 220/110kV substation. Truc Ninh 220kV substation and Thai Binh 220kV substation are key substations to transmit the power of Thai Binh 2 TPP to 220kV line and they are also the supply source substations for the 110kV substations in the area. Therefore, it is recommended that Truc Ninh substation should be put into operation in 2012.

- Tien Hai 220kV substation.


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- Thai Binh TPP – Tien Hai - Truc Ninh 220kV transmission line.

- 220kV Truc Ninh line connects to Nam Dinh-Ninh Binh line (4 circuits): connecting to Nam Dinh-Ninh Binh double circuit line. Currently Thai Bình-Nam Dinh-Ninh Binh 220kV line is a single circuit line. The Investment Project Report for the second line section from Thai Binh – Nam Dinh and Nam Dinh - Ninh Binh was approved (now it is in technical design period). The progress of the works should be sped up in order to connect 4 circuits from Truc Ninh connect to this line.


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APPENDIX 4: SPECIALIZED REPORT ON TARIFF METERING SYSTEM OF THAI BINH THERMAL POWER PLANT PROJECT

CHAPTER 1 GENERAL

1. Basis for preparing power metering project for power purchasing

Measurement Ordinance was issued on October 06, 1999 by the Ministry of Science, Technology and Environment.

Regulation of technical requirements of power metering equipment for power plants, issued together with Decision No. 02/2007/QD-BCN dated January 09, 2007 of the Minister of Ministry of Industry.

Letter No. 4894 CV / EVN-TTD-KD & DNT on: Design and install metering systems of power plants, substations, issued on September17, 2007 by Vietnam Electricity.

Circular No. 12/2010/TT-BCT on: Regulation of electricity transmission system, issued on April15, 2010 by the Ministry of Industry and Trade.

Letter No. 5276/QD-BCT on approval of the investment project of Thai Binh TPP construction, dated September 29, 2008 of the Ministry of Industry and Trade.

2. Brief description of Thai Binh TPP

Thai Binh TPP includes the Plant and 220 kV switchyard.

The Plant includes:

- Two generator – transformer units: G1-G2-GT1 and GT2. Each generator has a capacity of 300MW. Transformer has rate of 220/19kV

- Two generator terminals auxiliary transformers 19/6.6/6.6 kV+ 6.6 kV Bus bar

220kV switchyard includes:

- 8 breaker modules under bus bar diagram 3 / 2 for the sections:

Two 220kV transmission line bays to Thai Binh 220kV substation

One bay for start up transformer 225kV / 6.6 / 6.6 kV T1

Two feeders sections to the Plant (connected to two generator – transformer units)

- 220kV Bus bar

3. Scale of tariff metering part Pursuant to promulgated regulations the power metering system for power trading in Thai Binh TPP will be scaled as follows:

Main metering system located at:

- 02 points on the 220kV side of 02 transformers GT1, GT2

- 01 point on the 220kV side of auxiliary transformer 225 / 6.6 / 6.6 kV T1


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- 03 points adjacent to the metering point of the main metering system.


- Feeders for the 02 220 kV transmission lines to Thai Binh 220kV substation.

- 02 sections of the 220 kV (installed under Thai Binh 2 TPP project) N


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CHAPTER 2. TARIFF METERING SYSTEM

1. Functions of tariff metering system

a. Main tariff metering system :

The main power metering system shall determine accurately and completely the measurable quantities of power trading as a basis for payment of power between Vietnam Electricity and Thai Binh TPP.

b. Standby metering system :

- Backup for the main metering system as a basis for calculating the quantity of power trading in the case where the main metering system is not working correctly or under failure.

- Supervise and cross check the results of the main metering system under normal operation of the main metering system.

- Combine with the main metering system and other standby metering systems to calculate power production capacity for payment in some special cases.

c. The requirements for tariff metering system:

- Ensure sufficient supply of parameters and necessary data for the main metering system and standby metering systems to determine power for purchase / sale; to monitor operating condition, reliability of the metering system.

- Automatically record and store in the meters all the values and power index for both import and export at 24:00 hours on the last day of the billing period.

- Automatically collect metering data of main metering points and standby metering points.

- Metering data is collected automatically on computer for storage which is the basis for determining power purchasing / selling in the period.

- Automatic recording of quantities of active power at the identified metering points at a period every 30 minutes for both import and export of power.

- Power exchange data at metering points is collected daily, stored at Thai Binh TPP, then transmitted to the Communication Centre of EVN as a basis for management and system operation of the metering system and verifying the reliability of metering data.

2. Configuration of tariff metering system

Configuration of power metering system in Thai Binh TPP shall include:

- Current transformers

- Voltage transformers

- Connection boxes for power metering

- The power meters

- Metering circuits


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- Metering cubicle

- Equipment for data collection and transmission of metering data

- Safety equipment, sealing position, seal

3. Technical requirements for tariff metering system 3.1 Current Transformers

a. General requirement

- Having individual metering secondary coils used for metering equipment and tariff meters.

- Nominal secondary current to be 1A.

- Have a tamper seal location on the cover of the connection box for metering secondary coils supplied for metering equipment and tariff meters that ensures there has been no impact to the connection circuit if the seal is not broken.

- Current transformer for main metering shall have an accuracy level of 0.2 according to IEC-60044-1 or other equivalent standards.

- Current transformer for standby metering shall have an accuracy level of 0.5 according to IEC-60044-1 or other equivalent standards

b. Current transformers for main metering point and standby No.1 metering point

- Current transformer ratio: 400-800-1200/1A (for T1 220kV transformer side)

800-1200-2000/1A (for 02 of 220kV transformers side)

- Number of secondary coils: 06

- Accuracy level and rating:

Coil 1: Accuracy level 0.5-30VA for standby No.1 metering system & metering transducer

Coil 2: Accuracy level 0.2-30VA for main metering system

Coils 3,4,5,6: Accuracy level 5P20-30VA for protection

c. Current transformers for standby No.2 metering point

- Current transformer ratio: 800-1200-2000/1A.


- Accuracy level and rating:

Coil 1: Accuracy level 0.5-30VA for standby No.2 metering system

Coil 2: Accuracy level 0.5-30VA for metering transducer

Coils 3,4,5,6: Accuracy level 5P20-30VA for protection

3.2 Voltage transformers

a. General requirement


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- Having individual metering secondary windings for metering equipment and tariff meters.

- Nominal secondary system voltage is 110V AC

- Have a tamper seal location on the cover of the connection box for metering secondary windings supplied for metering equipment and tariff meters that ensures there has been no impact to the connection circuit if the seal is not broken.

- Voltage transformer for main metering shall obtain accuracy level of 0.2 according to IEC-60044-2 for induction voltage transformer, IEC-60044-5 for capacitor voltage transformer or other equivalent standards.

- Voltage transformer for standby metering shall obtain accuracy level of 0.5 according to IEC-60044-2 for inductive voltage transformer, IEC-60044-5 for capacitor voltage transformer or other equivalent standards.

b. Voltage transformers for main tariff metering point and standby No.1 tariff metering point

- Capacitance of capacitor: 4400pF

- Voltage transformer ratio: kV

3

11,0/

3

11,0/

3

11,0/

3

11,0/

3

220

- Number of secondary windings: 4

- Accuracy level, rating:

Coil 1: Accuracy level 0.2-50VA for main metering system



Coil 4: Accuracy level 3P-50VA for protection.

c. Voltage transformers for standby No.2 metering point

- Capacitance of capacitor: 4400pF

- Voltage transformer ratio : kV

3

11,0/

3

11,0/

3

11,0/

3

220


- Accuracy level, capacity:



Coil 3: Accuracy level 3P-50VA for protection.

3.3 Outdoor Marshalling Kiosk for tariff metering

- Intended use: to connect current circuits, voltage circuits for tariff metering. The voltage transformer and current transformer shall be in side by side compartments and connected in a single marshalling kiosk, details are as follows:


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- 01 marshalling kiosk for voltage transformer and current transformer of Thai Binh 220kV line bay

- 01 marshalling kiosk for voltage transformer and current transformer of Thai Binh 2 220kV line bay

- 03 marshalling kiosks for voltage transformer and current transformer conforming with 3 sections: 220kV side of T1 transformer and 02 Thai Binh TPP transformers.

- Method of lead sealing: clamp rows for current circuits, voltage circuits and the cubicle doors shall be lead sealed and protected.

- Cubicle shall have lighting provided and heating facilities,....

- Cubicle shall have protection level IP-55

- Dimensions:

Width: 400mm

Height: 600mm

Depth: 300mm

3.4 Tariff meters

a. General specifications

- Nominal Current : 1A

- Voltage (Neutral Phase):

- Meter type: 3 phases 4 wires

- Integrated function and programmable electronic Meter

- Various price schedules

- Metering active power and reactive power for both import and export according to 4 quadrant angles.

- Have the function of metering maximum power; recording total load diagram

- Have the function of connecting with computer, collecting and reading data at local and remote.

- Be energized from metering secondary voltage and keep operating upon loss of voltage of 1 or 2 phases and the meters shall be provided with internal battery supply for data storage.

- Having various hierarchies of passwords

- Have a tamper seal location for lead seals to prevent access to the wiring terminals or changing the setting data in the meters that ensures there has been no impact to the connection circuit if the seal is not broken.

- Have the function of storing metering data, load diagram for at least 60 (sixty) days with circulation of metering less than 30 (thirty) minutes and can be programmed for integral cycle.


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- Be able to auto record number and duration of voltage loss, number of programming and the time of programming.

- There is at least 01 RS232 standard communication port and 01 RS485 standard communication port.

- Implement multi-drop bus connection method.

- Complying with data collection, tariff metering software used in the center EVN.IT: IEE software of ITRON firm.

- Registered standard meter form to comply with the provisions of Measurement of Ministry of Science, Technology and Environment issued on 06/10/1999.

- The main meter shall reach accuracy level 0.2 with active power complying with IEC62053-22 and 2.0 for reactive power according to IEC62053-23 standard or other equivalent standards.

- The standby meters shall reach accuracy level 0.5 with active power complying with IEC62053-22 and 2.0 for reactive power according to IEC62053-23 standard or other equivalent standards.

b. Installation position

- The main meters shall be installed at the meter cabinet M1.

- The standby No. 1 and No. 2 meters shall be installed at the meter cabinet: M2.

3.5. Metering cabinets

Location of Installation: in the relay room of the control building.

- Type of cabinet: indoor, degree of protection IP-41.

- Intended use: To install the meters for tariff metering.

- Lead seal method: sealed at clamp rows for current circuit, voltage circuit, voltage circuit converter, cabinet doors in lead seal to protect.

- Cabinet shall be provided the lighting, drying facilities, cabinet cooling fan, ...

3.6. Tariff metering circuit:

- Secondary coils of CT, VT and secondary cables connected to tariff meters of the main metering system shall be not be used for any other purpose and shall be completely independent to the standby metering system.

- Secondary Cables of metering circuits shall be routed in the shortest path, with minimum number of points connected through the terminals and be provided with tamper seal locations for lead sealing of terminal strips or connection points. Secondary Cables of the main metering system shall be routed individually and directly connected with the connection box of CT, VT to metering cabinets without going through terminal stip of intermediate cabinets.

- If the meters source voltage is from one of the busbar VT’s through a voltage switch, the wiring terminals of the voltage switch shall be lead-sealed and the tariff meter shall be programmed to record the time and duration of voltage switching.

- Burden of the secondary circuit CT, VT, including tariff meter burden shall not exceed the nominal burden of CT, VT.


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- If the current circuit of the standby metering system is used in conjunction with other instrumentation devices it shall not affect the accuracy of the metering system and shall have provision for tamper sealing the entire current circuit, instrumentation equipment, tariff meters.

- Test connection boxes shall be installed for testing instrumentation equipment and under lead seal.

3.7. Data collecting and reading system of the tariff meter

- The tariff meters for power purchasing shall be installed so that the meter data can be remotely interrogated and comply with connections and having protocols with remote data collection software implemented in the data collect center.

- The meters for power purchasing shall be provided with communication ports, integrated communication equipment complying with RS232 standard (or RS485, Ethernet) and the modem in the meter shall allow remote connection to the meter via modem and data transmission line.

- Depending on the model of data collection communication equipment the mode of metering data transmission at a connection point shall be agreed between power buyer and seller. The data collection system shall be provided with a local computer to read and store data or via the centralized data collection device. Metering data collected at the local computer shall be transmitted to the database of the server located at the data collection center.

- Communication transmission environment shall use a dedicated telephone network. Environment and mode of communication transmission shall be secured to prevent unauthorized access.

- Communication equipment connected with the tariff meter shall be installed with appropriate lightning protection equipment to avoid the effects of lightning impulse spread through communication network causing damage.

- Transducers and isolation switches device test equipment connected network to a public service telecommunication network (PSTN) installed in the panel shall be in compliance with the safety requirements and facilitate system management.

3.8. Safety equipment, sealing position, lead seal and secure:

- The entire tariff metering system including secondary terminal boxes of the CT’s and VT’s, tariff meters, terminations, connections, current circuits, voltage circuits, auxiliary equipment, logic switches, meter cabinets and communication networks shall be tamper seals to prevent unauthorized access.

- Tariff meter Software shall be password protected with various hierarchy of access permissions.

- Tariff meter data after being read and transmitted to servers located in the metering position shall be encoded to prevent unauthorized changes.

- Management Software of tariff metering data reading, transmitting and collecting system shall be secured by various multiple levels of passwords to ensure the security, accuracy and reliability of metering data.


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CHAPTER 3: ESTABLISHING AND DEVELOPING DATA ACQUISITION FOR TARIFF METERING SYSTEM

1. Purpose of a data acquisition system establishment

- Implementing and establishing automatic data reading, collection and transmission system for metering power purchased between Thai Binh thermal power plant (Thai Binh TPP) and Vietnam Electricity.

- Monitoring operation status and reliability of tariff metering system for delivering and receiving power between Thai Binh thermal power plant and Vietnam Electricity.

2. Scope of data acquisition

Main power meters: TM-F1-2-1, TM-F2-2-1 and TM-F3-2-1

Standby tariff meters No1: TM-F1-2-2, TM-F2-2-2 and TM-F3-2-2

Standby tariff meters No 2: TM-F1-1-3 and TM-F2-1-3

3. Method of data acquisition and communication module connection of the meters:

3.1 Method of data collection:

For Thai Binh TPP data reading from meters shall be able to be performed according to the two following methods:

- Local data reading: read from the meters or via the computer used for collection of tariff metering data located at the station.

- Remote data reading: Tariff metering data of Thai Binh TPP can be read at Information technology center of EVN according to one of the two following ways:

Direct access to the meters

Access to the computer used for collecting tariff metering data located at the station.

Access, store and transmit the tariff metering data of Thai Binh TPP to 01 computer which has software installed for collecting tariff metering data.

- Access to load diagram data daily (every 30 minutes) of meters at Thai Binh TPP

- Store past data for checking, comparing and establishing the necessary capacity reports.

- Update data at the meters at Thai Binh TPP for treating meter failure.

- Data at 24:00h of the last day of the month shall be the base for NPT to issue power selling invoice and for payment.

Automatic data reading and collection system for tariff metering and power purchasing between Thai Binh TPP and Vietnam Electricity shall be designed to ensure the reading, transmitting and receipt of data from electronic meters is precise and stable.

Automatic data reading and collection system for tariff meters located at Thai Binh TPP and Vietnam Electricity can be cross-checked, monitored for proper operation of metering system and automatically update tariff data purchased between the two bodies continuously, quickly and precisely.


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3.2 Connecting communication module of the meters

Acquisition of local metering data:

Meters are connected via communication modules according to RS 485 standard and multi-drop bus connection. This type of connection allows connection of 32 meters. Tariff metering data shall be acquired and transmitted to 1 computer used for acquiring tariff metering data via 1 modem and PABX switchboard. This computer shall be equipped with software for accessing and analyzing the metering data.

Acquisition of remote metering data

For collecting remote metering data, Thai Binh TPP shall be equipped with 1 modem and telephone wires for the main meters, standby meter No. 1 and standby meter No. 2 which are connected by multi-drop bus connection.

The meters shall be connected in parallel with each other via UTP-CAT5 cable, RS 485 modules. Data shall be transmitted to the computer used for collecting tariff metering data at EVN and Thai Binh TPP via RS 232 module of master meter, 1 modem, PABX switchboard.

- Data from the meter will be read from the computer installed for the data collection, processing and analyzing software located in Thai Binh TPP and in EVN. The local and remote computers shall read data from meters and establish the charts, detailed and consolidated reports for the entire tariff metering system purchased between Thai Binh TPP and Vietnam Electricity.

- For the safety of the meters and communication equipment in the system, the telephone lines connected to the meters shall be fitted with special lightning protection equipment.

4. Operation specification

4.1. Auto data reading and collecting program:

- Through the data collection software of tariff metering, every day at specified time (not the same time among the entities) the auto data reading program installed in the computers of EVN and in the computers of Thai Binh TPP will automatically connect to all meters to read the tariff data, the capacity of this meter and transmit it to the database of the computer.

- From the data in the database, data collecting program will allow managing, setting diagrams, detailed reports for each individual metering point as well as summary reports for some meters depending on the specific requirements of the manager.

- Data required to be collected is as follows:

Daily monitoring data:

- Data and chart on active power (P), reactive power (Q) for import and generation in every 30 minutes.

- Total power for import and generation per day.

Monthly monitoring data:

- Chart on active power (P), reactive power (Q) for import and generation every 30 minutes in any day of the month.


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- The total power (P, Q) for import and generation each day of the month.

There are also summary reports as per the requirements for analysis and management (depending on the requirements to be agreed and supplemented later).

4.2. Manual meter data reading program:

Use the data collection program of tariff metering installed in tariff metering data collection computer of Thai Binh TPP to read the data in the meters, including the following parameters:

- Instant data of capacity and power recorder at the time of data reading connection.

- Closing data of capacity and power recorder of the meter at 0 hour of the first day of the month (meter is able to store closing data value of 13 last months).

- Information about the parameters of the meters metering circuit (current, voltage, phase angle, power,...).

- Information about meters security (number and timing of meter programming, the number and time of loss of voltage for meters, over current, meter hardware failure detecting, low battery,....)

- Data channels load chart (kWh and kVarh for import and export) of the meter.


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CHAPTER 4: LIST OF EQUIPMENT

List of equipment

No Name of equipment, material Unit Quanti

ty Notes

A Communication Equipment

1

PC Computer with configuration of at least: Intel Core Duo 3,0 GHz, RAM 2GB, HDD 320 GB, DVD-RW/CDROM-RW, 17” LCD Monitor, Keyboard, Mouse, Com, Serial port, 4USB port, Windows XP.

Set 01

2 Modem connecting computer to PABX switchboard.

Unit 01

3 Modem connecting meter to PABX switchboard.

Unit 01

4 Software: Windows-XP or modern version, Power Master, Unit Data Link Plus, Data Vision.

Set 01 Attached with the

computer

5 Postal telephone subscriber Listed in

Communication part

6 Communication cable and accessories, including:

At Control building of Thai Binh TPP 220kV switchyard

- Connecting from modem of the meter to PABX switchboard (at Center control building) : 500m

- Connecting from computer used for collecting tariff metering data to PABX switchboard (at Center control building) : 500m

At EVN headquarter-18 Tran Nguyen Han:

- Connecting from computer used for acquiring the tariff metering data of EVN IT to existing modem: 50m

- Connecting from existing modem to PABX switchboard of EVN Telecom VT1 : 150m

Set 01

B Equipment of secondary power part

1 Meter Cubicle M1 (including 3 meters and Cubicle 01


264

No Name of equipment, material Unit Quanti

ty Notes

accessories)

2 Meter Cubicle M2 (including 5 meters and accessories)

Cubicle 01

3 Outdoor connection box for current circuit and voltage circuit for tariff metering

Box 05

4 UTP-CAT5 communication cable and accessories (for multi-drop bus connection between meters) 8 pairs type, including:

At Control building of Thai Binh TPP 220kV switchyard:

- For multi-drop bus connection between meters and modem of meter: 20m

- For connecting meter to computer used for acquiring tariff metering data: 60m

Set 01

Volume 6 Electrical Equipment (Issuing Version of 27-01-2011)(1)

Documents

Transcript of Volume 6 Electrical Equipment (Issuing Version of 27-01-2011)(1)