TO-HQ-02-013 Rev 00 Philosophy for Emergency Generator and S.pdf

OMV Exploration & Production

00 Final Issue JS 31/5/05 JEA 31/5/05 PZ 03/6/05 MF 03/6/05

A2 Client Comments Incorporated JS 28/5/05

A1 Issued for Comment /Approval RH 22/12/04 JS 31/12/04

Issue Rev

Issue or Revision Description Origin By

Date Chkd By

Date Appd By Date Appd By

Date

Philosophy for

Emergency Generator and Switchboard Onshore

Document Number

TO-HQ-02-013-00

OMV Exploration & Production GmbH

Document Number Rev Page Philosophy for Emergency Generator and Switchboard

Onshore TO-HQ-02-013 00 2 of 22

Revision Description of revision A1 For Comment/Approval

A2 Client Comments Incorporated

00 Final Issue




Contents

1.0 PREFACE .......................................................................................................................4

2.0 DEFINITIONS .................................................................................................................4

3.0 ABBREVIATIONS...........................................................................................................4

4.0 INTRODUCTION.............................................................................................................4

5.0 APPLICABLE CODES, STANDARDS AND REGULATIONS........................................5 5.1 Codes and Standards list.......................................................................................................... 5 5.2 References ................................................................................................................................. 6

6.0 SYSTEM GOAL ..............................................................................................................6

7.0 SYSTEM BOUNDARIES ................................................................................................7

8.0 DESIGN PHILOSOPHY..................................................................................................7

9.0 DESIGN CONSIDERATIONS .........................................................................................8 9.1 General ....................................................................................................................................... 9 9.2 Prime Mover ............................................................................................................................. 10 9.3 Starting Methods ..................................................................................................................... 11 9.4 Generator.................................................................................................................................. 12 9.5 Generator control panel .......................................................................................................... 14 9.6 Emergency Switchboard......................................................................................................... 16

10.0 DESIGN CRITERIA.......................................................................................................20

11.0 DOCUMENTATION REQUIREMENTS.........................................................................20

12.0 REGULATORY AUTHORITY REVIEW REQUIREMENTS ..........................................20




1.0 PREFACE

This Philosophy defines the OMV Exploration & Production GmbH corporate policy on the design of Emergency Generators and Switchboards for onshore hydrocarbon production and processing facilities. The document specifies basic requirements and criteria, defines the appropriate codes and standards, and assists in the standardisation of facilities’ design across all onshore operations.

The design process needs to consider project specific factors such as the location, production composition, production rates and pressures, the process selected and the size of the plant. This philosophy aims to address a wide range of the above variables, however it is recognised that not all circumstances can be covered. In situations where project specific considerations may justify deviation from this philosophy, a document supporting the request for deviation shall be submitted to OMV E&P for approval.

Reference should be made to the parent of this philosophy, document number TO-HQ-02-001 for information on deviation procedures and Technical Authorities, general requirements and definitions and abbreviations not specific to this document

2.0 DEFINITIONS

There are no definitions with particular relevance to this document.

3.0 ABBREVIATIONS

The following abbreviations are relevant to this document:

AVR Automatic Voltage Regulator

UL Underwriters Laboratory

4.0 INTRODUCTION

The tenets of this philosophy are enshrined in the belief that upon loss of mains supply the following requirements must be secured by the transfer from mains supply to emergency supply.

• Safety of Personnel. • Security of the surrounding environment.




• Mitigation of the destruction of equipment.

Services necessary to secure these requirements shall be identified in Document No TO-HQ-02-011 - Philosophy for Electrical Design Onshore and plant-specific risk analyses.

5.0 APPLICABLE CODES, STANDARDS AND REGULATIONS

Codes, standards and regulations referred to in this philosophy shall be of the latest edition and shall be applied in the following order of precedence: -

• Local Regulations,

• The provision of this document,

• International standards (e.g. ISO, IEC etc),

• National standards. Design of the emergency generator system shall comply with the standards listed within this philosophy, however, for instances where local standards are more onerous local standards shall apply.

5.1 Codes and Standards list NFPA 70 National Electrical Code API RP 540 Electrical Installations in Petroleum Processing Plants Institute of Petroleum Model Code Of Safe Practice, Part

1, Electrical Safety Code NEMA MG1 Motors and Generators NEMA MG2 Safety Standard for Construction and Guide for

Selection, Installation, and Use of Electric Motors and Generators

IEC 60034-1 Rotating electrical machines – Part 1: Rating and performance

IEC 60204-1 Electrical equipment of industrial machines – Part 1: General rules

IEC 60439-1 Low-voltage switchgear and control gear assemblies - Part 1: Type-tested and partially type-tested assemblies

IEC 60947-1 Low-voltage switchgear and control gear - Part 1: General rules

IEC 60947-4-1 Low-voltage switchgear and control gear - Part 4-1: Contactors and motor-starters - Electromechanical

http://www.techstreet.com/cgi-bin/detail?product_id=8310




contactors and motor-starters IEEE C37.20.1 IEEE Standard for Metal-Enclosed Low-Voltage Power

Circuit Breaker Switchgear UL 891 Dead-Front Switchboards UL 1558 Metal-Enclosed Low-Voltage Power Circuit Breaker

Switchgear ISO 3046-1 Reciprocating internal combustion engines --

Performance -- Part 1: Declarations of power, fuel and lubricating oil consumptions, and test methods -- Additional requirements for engines for general use

BS 5514-3 Reciprocating internal combustion engines: performance. Specification for test measurements

ISO 3046-4 Reciprocating internal combustion engines -- Performance -- Part 4: Speed governing

ISO 3046-5 Reciprocating internal combustion engines -- Performance -- Part 5: Torsional vibrations

BS 5000-11 Specification for rotating electrical machines of particular types or for particular applications. Small-power electric motors and generators

BS 5000-3 Specification for rotating electrical machines of particular types or for particular applications. Generators to be driven by reciprocating internal combustion engines

5.2 References

TO-HQ-02-011 Philosophy for Electrical Design Onshore TO-HQ-02-012 Philosophy for Main Generators and Switchboard

Onshore TO-HQ-02-039 Philosophy for Rotating and Reciprocating Equipment

Onshore

6.0 SYSTEM GOAL

The emergency generator and switchboard are intended to provide a secure electrical supply, independent of any external supply and the main generation




system for the installation, for vital services for which a short break in supply is tolerable. Typically, the services will be those that present a load of a magnitude such that a no-break battery UPS would not be practicable, or economically justified by the risk mitigated by the provision of such a system, such as emergency lighting or HVAC for buildings housing equipment essential for the restoration of normal conditions following a power failure. Alternatively, the emergency system will act as a back-up for systems which have a no-break supply, but for which it would not be practicable to install batteries having a capacity sufficient to maintain power autonomously for the duration of all foreseeable power outages, such as fire fighting systems, plant control systems, aircraft warning systems, etc. The analysis of which services which will require an emergency supply, and for what duration, is dealt with in more depth in Document No TO-HQ-02-011 - Philosophy for Electrical Design Onshore.

7.0 SYSTEM BOUNDARIES

The boundaries of the emergency generator and switchboard system are the:

• interface to the main electrical system

• Interface to the PCS and HMI

• connections for power supplies to emergency services

8.0 DESIGN PHILOSOPHY

The emergency generator set and switchboard shall be of types accepted as providing a high degree of reliability, within the capabilities of normal industrial equipment: It is not envisaged that any system requiring a higher level of integrity should be reliant solely upon an emergency generator. The emergency switchboard shall be supplied, by an interconnector circuit, from the main power distribution system, to reduce the running hours required of the emergency generator. Nevertheless, the arrangements should facilitate regular on-load testing. In normal operation, the emergency generator shall start automatically, then be connected automatically to the emergency switchboard, on detection of loss of voltage at the main switchboard from which the emergency switchboard is normally fed.




The starting and control arrangements shall be totally independent of the main power system, as should be the fuel supply. The capacity of the emergency fuel supply shall be determined following consideration of the duration for which the emergency supply is required to be available. The emergency generator and switchboard shall be located outside any hazardous area or high fire risk location. Consideration should also be given to locating the equipment so as to enhance the likelihood of it remaining operational in the event of a major incident, where the normal hazardous area classification boundaries no longer apply. Consideration should also be given to the benefits of configuring the emergency power distribution network as a non-earthed (IT) system, so that a single earth fault does not result in loss of services on the faulted circuit. The Philosophy is structured on the basis of the elements shown below, each of which shall be allocated to a specific sub-section. Within each sub-section, the reader shall be directed to the associated clause within the NEC for core philosophy information and be provided with detail on specific issues.

• General Design Considerations and Placement

• Prime Mover

• Starting Method

• Generator

• Generator Control Panel

• Alarms and Shutdowns

• Emergency Switchboard

• Busbars

• Circuit Breakers

• Generator incomer

• Interconnector Circuit

• Feeder Circuits

9.0 DESIGN CONSIDERATIONS

The ratings of the generator set and switchboard depend upon the loads determined by the risk analyses and system design studies, and the applicable regulations, as requiring an emergency supply. It is expected that these would not fall into a band where High Voltage generation would be appropriate: the




detailed references within this document to equipment design and standards relate, then, to Low Voltage systems. The emergency switchboard should be supplied from the main power supply system by an interconnecting feeder during normal operation. The emergency switchboard should, preferably, supply only emergency loads. However, when non-emergency loads are supplied from this switchboard, arrangements are to be made for their disconnection to prevent overloading of the generator.

9.1 General For core Philosophy guidance, refer NEC, Articles 700 and 705. Specific Issues: This philosophy considers that: The generator set shall consist of a diesel reciprocating engine prime mover, mounted on a bedplate with, and directly coupled to, an a.c. generator. The maximum voltage delivered by the generator shall be below 1000V at 50/60Hz and is, subject to compliance with regulatory requirements, regulatory requirements and in accordance with the system design philosophy (see Document No TQ-HQ-01-011 – Philosophy for General Electrical Design Onshore), ungrounded or grounded (earthed). The Interconnector feeder shall be protected against short-circuit and overload at the point of connection to the main system, and as a minimum, short-circuit at the emergency board. The Interconnector feeder shall be disconnected automatically at the emergency switch board upon loss of mains power. Upon loss of mains supply the emergency Generator shall start and shall be connected to emergency switch board when its output voltage has reached between 85% and 95% of its nominal value: this operation shall be completed within 10 to 45 seconds. All non-emergency loads shall have been automatically disconnected from the emergency switch board. The rating of the emergency generator shall be based on continuous operation with no diversity factor assumed. The Emergency Generator and Switchboard shall be housed in a building or Enclosure having passive fire protection to a level determined by a previously conducted risk assessment. The design of the building or enclosure shall take into account blast overpressure, so that the risk of loss of the emergency supply,




as a result of explosion, is reduced to a level which is as low as is reasonably practicable. A fuel-oil tank, having a capacity sufficient to support the emergency generator set for the period of autonomous operation required for the installation, shall be located within the building or close to it: if externally located, it should have the same level of passive fire protection as the emergency generator building. Building and equipment design should allow for earthquake protection in areas of known high risk.

9.2 Prime Mover For core Philosophy guidance, refer NEC Article 700-12. Account is also to be taken of the relevant requirements of Document No TO-HQ-02-039 - Philosophy for Rotating and Reciprocating Equipment Onshore Specific Issues: This philosophy considers that: The engine should be selected from the Manufacturer’s standard range, and should be of a type, rating and method of manufacture for which satisfactory service experience can be confirmed. The engine should generally be of the water cooled type, with a water to air heat exchanger (radiator), although consideration could be given to the use of direct air cooled engines for small installations. For either type of engine, an electric sump heater shall be provided where necessary to ensure reliable starting under the coldest conditions encountered at the site. Water cooled engines shall also be provided with a jacket heater in order to ensure rapid starting and acceptance of load under these conditions. Coolant radiators mounted externally or in the wall of the generator building shall be provided with suitable louvres or shutters for weather protection. Where the generator building is required to provide a given level of passive fire protection, this should be maintained by the provision of fire dampers and suitable insulation for the radiators. Externally mounted radiators shall also be protected similarly. The rated power of the engine, for continuous operation and overload conditions, determined in accordance with ISO 3046-1, shall be sufficient to meet the duty required of the emergency generator set as determined by the system design studies. Any likely deterioration under the proposed maintenance regime for the installation should be taken into account in determining the rating. The prime mover ratings shall be adjusted for the highest expected ambient temperatures and derated, where necessary, for total system inlet and exhaust pressure losses.




Special consideration should be given, when sizing the prime mover, for service where large motors are to be started across the line. Drive belts for auxiliary equipment shall be guarded appropriately, with full allowance being made for adjustment throughout the life of the belt. Combustion air filtration shall be provided as required by local conditions and the point from which air is drawn. Provision shall be made, by means of a blow-in door or similar, for the engine to be able to continue running if the intake filter should become blocked. Where the generator building is required to provide a given level of passive fire protection, this should be maintained by the provision of fire dampers and suitable insulation for the ventilation air intakes for the building and the combustion air intake for the engine, if ducted through the wall of the building. The engine should be provided with an aspiration air intake valve, activated under emergency shutdown conditions, to ensure safe shutdown in the event of a major release of flammable gas. Means should be provided, if the engine is turbo-charged, for automatically draining, or preventing the formation of, condensate within the inlet manifold.

9.3 Starting Methods For core Philosophy guidance, refer NEC Article 700. Specific Issues: This philosophy considers that: Compressed air, hydraulic, or electric start methods are acceptable, provided that the engine manufacturer can confirm satisfactory field experience for the arrangement offered. Where justified by the economic or safety consequences of failure to start, consideration should be given to the provision of redundant starting arrangements, preferably of different types. Whichever system or combination of systems is employed, two independent sources of stored energy, each sufficient for at least three consecutive start attempts, shall be provided. The electrical supplies for the necessary pumps, compressors and battery chargers shall be taken from the emergency switchboard. The pumps, compressors or battery chargers should be rated so as to be capable of recharging one of the sources of stored energy to a level sufficient to provide a further three start attempts within an acceptable period. 15 minutes would be appropriate for hydraulic and compressed air systems, and one hour,




or as short a period as permitted by the battery type employed, would be appropriate for battery start arrangements. Air start systems shall be of the air driven starting motor type, rather than cylinder air injection, and shall be provided with an electrically driven air compressor, one or two air receives with all necessary valves and drains, pressure gauges and control arrangements. Provision should be made for connecting an external compressed air supply for initial start. Hydraulic start systems shall include one or two accumulators, provided with a pressure gauges and automatically charged by an electrically driven pump. Provision should be made for charging the accumulator by a manually operated pump, or other means, for initial start. Electric start systems shall be provided with batteries of a type specifically recognised as suitable for float charging, preferably without need for regular equalising, and deep discharge. Nickel-Cadmium batteries are generally preferred, although suitably specified Lead–acid batteries (Lead – Calcium or Lead – Selenium) may also be accepted. The batteries should be housed in suitably robust battery boxes of non-conducting material, with ventilation openings sized so as to prevent the accumulation of an explosive atmosphere during charging. It may be assumed that openings at top and bottom of the box, each having a total area of 50 cm2 for each 1 m3 of battery box volume would suffice.

9.4 Generator For core Philosophy guidance, refer NEC Articles:- 445, 700. Specific Issues: This philosophy considers that: The generator shall be designed to perform in accordance with NEMA Standards Publication MG1 or an equivalent IEC or national standard. The generator should be of the revolving field, brushless, type, so as to eliminate all arcing contacts and to reduce maintenance requirements. The use of a permanent magnet exciter is the preferred method, to avoid risk of failure, to achieve excitation after a lengthy period out of service. The generator should have a design temperature rise of 80°C, by resistance, (NEMA Class B), but be constructed with a minimum of NEMA Class F insulation to provide optimum balance between initial cost and long-life operations. The generator shall be derated in accordance with manufacturer’s recommendations if operated in a higher ambient temperature than for which its rating has been determined (normally 40°C).




The generator shall be capable of an overload power of not less than 10 per cent at its rated power factor for a period of 15 minutes without injurious heating. It shall also be capable of withstanding on test, without injury, the following momentary overload: an excess current of 50 per cent for 15 seconds after attaining the temperature rise corresponding to rated load, the terminal voltage being maintained as near the rated value as possible. This does not apply to the overload torque capacity of the prime mover. The Enclosure of the generator may be of the open, drip-proof, type, provided that the generator set is housed in a building, as recommended. However, if the building has a water spray or water mist fire extinguishing system, an enhanced degree of protection, sufficient to allow the generator to continue to function in the event of spurious operation of the fire extinguishing system, shall be specified. For optimum protection of the windings of a generator installed outdoors, a totally enclosed type of construction would be required. Anti-condensation heaters should be provided to keep windings dry when the generator is not operating. The lubrication arrangements for bearings shall include effective means to ensure that lubricant does not reach the machine windings or other conductors and insulators. Where the shaft voltage of the generator, measured between shaft ends, may exceed a value acceptable for the type of bearing employed (250 mV for rolling element bearings), suitable bearing insulation arrangements shall be provided, with a single, disconnectable, earth connection for equipotential bonding purposes. The generator shall be constructed such that, under any operating conditions, it is capable of withstanding the effects of a sudden short-circuit at its terminals without damage. The generator shall be provided with automatic means of voltage regulation; voltage build-up is not to require an external source of power. Provision shall be made to safeguard the distribution system should there be a failure of the voltage regulating system resulting in a High Voltage. Solid state voltage regulators are preferred for high reliability, long life, fast response and stable regulation. The voltage regulators for machines rated in excess of 200kVA should be protected by the provision of under-frequency and overvoltage sensors. The voltage regulator should have an adjustable droop characteristic, or be otherwise arranged, to allow parallel operation with the main power system. Consideration may also be given to automatic power factor control, if extended periods of parallel operation are anticipated.




If necessary for operation of protective devices under short-circuit conditions, the regulator should be equipped with series boost support equipment, or should be provided with a separate source of power such as a permanent magnet generator. Similar measures may be desirable for coordinating protective devices or starting large motors. The generator and its voltage regulation system shall be capable of maintaining, under steady state short-circuit conditions, a current of at least three times the full load rated current for a duration of at least two seconds or, where precise data is available, for the duration of any longer time delay which may be provided by a tripping device for discrimination purposes. The voltage regulation of the generator, with its regulating equipment, shall be such that, at all loads, from zero to full load at rated power factor, the rated voltage is maintained within ±2,5 per cent under steady conditions. There is to be provision at the voltage regulator to adjust the generator no load voltage. The generator and excitation system, when operating at rated speed and voltage on no-load, shall be capable of absorbing the suddenly switched, balanced, current demand of the largest motor or load at a power factor not greater than 0,4 with a transient voltage dip which does not exceed 15 per cent of rated voltage. The voltage shall recover to rated voltage within a time not exceeding 1,5 seconds. The transient voltage rise at the terminals of the generator is not to exceed 20 per cent of rated voltage when rated kVA, at a power factor not greater than 0,8, is thrown off.

9.5 Generator control panel For core Philosophy guidance, refer NEC Articles 445 and 700: for matters of electrical safety, refer NEC Articles 110, 408 and 409, as far as relevant: otherwise, the panel shall be constructed in accordance with the requirements of the manufacturer of the generator set. The control panel shall be supplied either as a free-standing panel or a panel to be incorporated in the switchboard. The generator should be arranged to operate in parallel with the main supply, for periods sufficient to facilitate transfer of load between main and emergency supply. This is to aid testing the emergency system and restoration of services after a power outage. The generator control panel should be equipped with:

• control logic (preferably utilising hard wired relay logic, for ease of fault finding and rectification, and predictable operation under all conditions);




• annunciator panel including audible alarm;

• electronic governor and AVR (may be incorporated in skid control unit);

• metering;

• synchronising equipment;

• external control switches;

• battery charger (may also be supplied as separate free standing unit). The following features should be provided on the front of the panel:

• annunciator panel, complete with audible alarm and accept/reset/lamp test

• push-buttons (see Alarms and Shutdowns)

• auto/manual start selector switch;

• start-stop push buttons;

• lamp test button;

• emergency stop push-button;

• controls for manual electric and hydraulic cranking;

• synchroscope and synchronising lights;

• excitation switches: manual/auto and on/off;

• engine tachometer;

• generator metering (volts, amps, kW, power factor, frequency, excitation

• current);

• circuit-breaker trip/neutral/close switches (if required);

• hours-run meter;

• raise/lower speed switch with spring return to neutral position;

• raise/lower volts switch with spring return to neutral position;

• battery voltage meter and battery charging ammeter. The ingress protection of the panel shall be suitable for its location. Drip proof/NEMA type 2/IP22 shall be suitable if located within the generator room and not subject to water spray from fire extinguishing system; NEMA Type 3 or 4/IP55 or better, otherwise.




The power supply for the panel shall have a battery backup, which should be separate from the engine start batteries.

Alarms and Shutdowns The generator set shall shut down automatically upon loss of lubricating oil pressure, overspeed, or operation of a fixed fire extinguishing system in the emergency generator room. The overspeed shutdown shall operate independently of the governor system and should be set at no more than 115% of rated speed. Alarms shall be provided for low oil pressure and high cooling water temperature. Consideration may also be given to the inclusion of the following alarms, according to the rating of the set and the recommendations of the manufacturer:

• Low lubricating oil level;

• Low jacket water level;

• Underspeed;

• Vibration;

• High lubricating oil temperature;

• Undervoltage;

• Underfrequency;

• Loss of excitation;

• Generator differential;

• Overfrequency;

• High Stator Winding Temperature

• Fuel System (Low, Low Low, High and High High)

9.6 Emergency Switchboard For core Philosophy guidance, refer NEC Articles:- 110, 480, 700 and 705. Specific issues are addressed below.




General requirements The switchboard should be arranged to provide convenient and safe access to qualified personnel to operate and perform maintenance on the equipment. An unobstructed space not less than 1 m wide shall be provided in front of the switchboard. Where the switchboard contains withdrawable equipment, the unobstructed space shall not be less than 0,4 m wide with this equipment in its fully withdrawn position. Where necessary, the space at the rear of the switchboard is to be ample to permit maintenance and in general not less than 0,7 m. In any event, the arrangements are to comply with the relevant statutory requirements, e.g. those of the NEC, Art.110. The spaces required for access shall have non-slip surfaces, electrically insulated, or provided with insulating mats. The switchboard should, preferably, meet the requirements of ANSI C37.20.1 or UL 1558 for Low Voltage metal enclosed power circuit breaker switchgear. Consideration may also be given to the use of a switchboard compliant with UL Std 891 for dead-front switchboards or international standards such as IEC 60439, Low Voltage switchgear and control gear assemblies. The ingress protection (IP) of the switchboard shall be suitable for its location. Drip proof/NEMA type 2/IP22 shall be suitable if located within the generator room and not subject to water spray from fire extinguishing system; NEMA Type 3 or 4/IP55 or better, otherwise. The short-circuit ratings of the switchboard busbar system shall be adequate for the prospective fault level at the switchboard. The rated short-circuit making and breaking capacity of every protective device shall be adequate for the prospective fault level at its point of installation. The construction of the switchboard should be of a type that confines an internal fault in a busbar dropper, feeder or starter compartment to the affected unit, so that other parts of the switchboard remain fit for service. Consideration should be given to the provision of windows or removable panels to allow safe on-load thermographic examination of the internal load current carrying parts of the switchboard.




Where the emergency generation and distribution system is to operate as an insulated or high resistance grounded system, ground fault indication and alarm should be provided.

Busbars Busbars and their connections shall be of copper or aluminium, all connections being so made as to inhibit corrosion/oxidization between current-carrying mating faces, which may result in poor electrical contact giving rise to overheating. Busbars and their supports shall be designed to withstand the mechanical stresses which may arise during short-circuits. For bare conductors, where no precautions are taken against surface oxidization, the temperature rise limit at rated normal current shall not to exceed 45°C. Where suitable precautions are taken against surface oxidization, e.g. by using silver, nickel or tin coated terminations, a temperature rise limit not exceeding 60°C is permitted. Where the busbar temperature rises are above 45°C it is to be ensured that there is no adverse effect on equipment adjacent to and/or connected to the busbars and that the temperature rise limits of any materials in contact with the busbars are not exceeded. Circuit-breakers Circuit-breakers shall comply with one of the following Standards, amended where necessary for ambient temperature: ANSI C37.13 (air power circuit breakers); UL489 (moulded case circuit breakers) or international standards such as IEC 60947-2: Low Voltage switchgear and Control gear, Pt 2: Circuit-breakers; the devices and the standards with which they comply shall be compatible with the standards for construction of the switchboard and the applicable regulatory requirements. Generator incomer The generator incomer circuit shall be provided with a circuit-breaker arranged to open simultaneously, in the event of a short-circuit, an overload or an under-voltage condition. This circuit-breaker shall be provided with reverse power protection with time delay, selected or set within the limits of 2 per cent to 15 per cent of full load to a value fixed in accordance with the characteristics of the prime mover.




The generator circuit-breaker short-circuit and overload tripping arrangements, or fuse characteristics, shall be such that the machine's thermal withstand capability is not exceeded. A synchronising relay should be provided in the breaker closing circuit or undervoltage release circuit of generator and interconnector circuit breakers to prevent out-of-phase paralleling. Consideration should be given to the installation of automatic synchronising controls, particularly where the rating of the unit is greater than 300kVA.

Interconnector circuit The interconnector circuit shall be provided with a circuit breaker offering, at least, short-circuit protection. Interlocking controls should be provided to ensure that the circuit breaker is open when the generator breaker is closed onto a dead bus. Feeder circuits Isolation and protection of each feeder circuit shall be ensured by a multipole circuit-breaker or linked switch with a fuse in each insulated conductor. Protection against short-circuit currents shall be provided by circuit-breakers or fuses. The rated short-circuit making and breaking capacity of every protective device shall be adequate for the prospective fault level at its point of installation. Motors shall be protected individually against overload and short-circuit. Every electric motor shall be provided with efficient means for starting and stopping so placed as to be easily operated by the person controlling the motor. Every motor above 0,5 kW shall be provided with the following control apparatus:

• means to prevent undesired restarting after a stoppage due to low volts or complete loss of volts, except where a dangerous condition might result from the failure to restart automatically;

• means for automatic disconnection of the supply in the event of excess current due to mechanical overloading of the motor.

Where fuses are used to protect polyphase motor circuits, means shall be provided to protect the motor from unacceptable overcurrent in the case of single phasing. The motor control gear shall be suitable for the starting current and for the full load rated current of the motor.




In order to ensure the ready availability of the emergency source of electrical power to supply emergency circuits, arrangements shall be made for the disconnection of any non-emergency loads to prevent overloading of the generator. The arrangements may, when the generator is overloaded, automatically disconnect sufficient non-emergency circuits from the emergency switchboard to ensure its continued safe operation. Additionally or alternatively, the arrangements may include automatic disconnection of non-emergency loads from the emergency switchboard upon loss of the main supply.

10.0 DESIGN CRITERIA

The essential design criteria are referenced in Sections 8 and 9. It is recommended, however, that the ratings of emergency generator and switchboard and the design of the switchboard should allow for the expansion of the plant and additional or enhanced loads.

11.0 DOCUMENTATION REQUIREMENTS

Technical manuals including the following information shall be provided:

• Drawings and leading particulars, including data sheets giving performance data, operating parameters, etc., for all items.

• Installation information, sufficient to enable correct installation of the equipment.

• Commissioning information, sufficient to allow initial putting into service and re-commissioning after a major overhaul.

• Operating particulars, such that operators not having familiarity with the equipment can operate it safely.

• Maintenance data and procedures.

12.0 REGULATORY AUTHORITY REVIEW REQUIREMENTS

Generally, works test certificates showing compliance with the relevant constructional and performance standard(s) shall be required for all major items of equipment.

Engine and Mechanical Arrangements




It is preferable that the engine be constructed under a quality assurance scheme approved by the relevant authority. In this case, details of manufacturer, type and rating of the engine may suffice. Otherwise, full constructional details may be required. Apart from drawings and details of the engine itself, the following is required:

• Schematic drawings of starting air or hydraulic system

• Schematic drawings of oil fuel system

• Schematic drawings of lubricating oil system

• Schematic drawings of cooling water system

• Torsional vibration calculations for the generator set, demonstrating that natural frequencies of vibration are removed from firing impulse frequencies, vibration stresses in shafting and coupling do not exceed acceptable values and that generator rotor vibratory torques and amplitudes do not exceed acceptable values.

Control and Alarm Arrangements

• Description of operation with explanatory diagrams.

• Line diagrams of control circuits.

• List of monitored points.

• List of control points.

• List of alarm points.

• Test schedules (for both works testing and commissioning) Switchboard and Power Distribution Single line diagram of emergency power and lighting systems which is to include:

• ratings of machines, transformers, batteries and semiconductor converters;

• all feeders connected to the emergency switchboard;

• make, type and rating of circuit-breakers and fuses.

• Simplified diagrams of generator circuits, interconnector circuits and feeder circuits showing:




protective devices, e.g. short-circuit, overload, reverse power protection; instrumentation and synchronising devices; load shedding arrangements; remote stops; earth fault indication/protection arrangements.

• Calculations of the minimum and maximum value of short-circuit currents at the emergency switchboard, when fed from the emergency generator and when fed from the main power system;

• Details of circuit-breaker and fuse operating times and discrimination curves demonstrating co-ordination of the protective device characteristics.

• Arrangement plans of the emergency switchboard.

• Schedule of normal and emergency operating loads on the system estimated for the different operating conditions expected.

The following may also be required:

• A test report or calculation to verify the short-circuit withstand strength of the busbar system;

• A test report or calculations to verify the rated current assigned to the busbar system;

• Documentation confirming that protection systems have been developed using a systematic design procedure incorporating verification and validation methods

TO-HQ-02-013 Rev 00 Philosophy for Emergency Generator and S.pdf

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