MAHARASHTRA STATE ELECTRICITY TRANSMISSION COMPANY LTD

VOL - II

TECHNICAL SPECIFICATION (MSETCL/JBIC/ICB/T0503/0208)

OF

50 MVA,

132KV CLASS

POWER TRANSFORMERS

2

TECHINICAL SPECIFICATION SECTION : TRANSFORMER

CONTENT

SR. Clause No. Description Page No. No. 1 1.0 Scope 3

2 2.0 Standards 4

3 3.0 Auxiliary power supply 5

4 4.0 Principal parameters 5

5 5.0 Duty requirements 5

6 6.0 Tests 35

7 7.0 Inspection 43

8 8.0 Quality Assurance Plan 44

9 9.0 Performance Guarantee 44

10 10.0 Documentation 45

11 11.0 Packing & Forwarding 46

12 12.0 Training 46

13 13.0 Supervisory Erection & Commissioning 47

14 14.0 List of Mandatory Spares 47

15 15.0 Information to be filled the Tenderer 47

16 Annexure-A1 Principal Technical Parameters

(50MVA, 132/33KV) 49

(50MVA, 132-110/33KV) 52

17 Annexure-B Schedule for Guaranteed Tech. Parameters

50MVA, 132/33KV 55

50MVA, 132-110/33KV 63

18 Annexure B1 Bill of Material 69

19 Annexure B2 List of Mandatory Spares 70

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MAHARASHTRA STATE ELECTRICITY TRANSMISSION COMPANY LTD.

TECHNICAL SPECIFICATION

GENERAL SPECIFICATION

1.0 SCOPE 1.1 This specification provides for design, manufacture, and inspection and testing

before dispatch, packing and delivery at destination sub-stations of power transformers complete with all fittings, accessories, associated equipments specified herein. The scope of work shall also include, at the option of the purchaser, supervision of Erection, Testing and Commissioning of all the equipments supplied under this specification.

1.2 It is not the intent to specify completely herein all details of the design and

construction of equipments. However, the equipment shall conform in all respects to standards of engineering, design and workmanship listed in clause no.2 and shall be capable of performing in continuous commercial operation up to the supplier's guarantee in a manner acceptable to the purchaser, who will interpret the meanings of drawings and specification and shall have the power to reject any work or material which, in his judgment, is not in accordance therewith .The equipments offered shall be complete with all components necessary for their effective and trouble free operation. Such components shall be deemed to be within the scope of supplier's supply, irrespective of whether those are specifically brought out in this specification and/or the commercial order or not.

1.3 The transformers shall conform in all respects to high standards of engineering,

design, Workmanship and latest revisions of relevant standards at the time of offer and the purchaser shall have the power to reject any work or material which, in his judgment, is not in full accordance therewith.

1.4 The equipment to be supplied against this specification shall be suitable for satisfactory Continuous operation under the following tropical conditions: -

a) Maximum ambient air temperature (0C) 50

b) Minimum ambient air temperature (0C) 3.5

c) Average daily ambient air temperature (0C) 40

d) Relative humidity (%) 10-100

e) Maximum rainfall per annum (mm) 1450

f) Maximum altitude above mean sea level (m) 1000

g) Maximum wind pressure (Kg./m2) 195

h) Isoceraunic level (days/year) 50

i) Seismic level (Horizontal acceleration) 0.39

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2.0 STANDARDS 2.1 The transformers, accessories and associated equipment shall conform to the latest

revision and amendments of standards as given below, except to the extent explicitly modified in the specifications.

2.2

Indian Standard No.

Title International & Internationally recognized Standard

IS-325 Three phase Induction motors IEC-34 IS-335 Insulating oils for Transformers and

Switchgear IEC-296, BS-148

IS-778 Gunmetal gate, globe-valves for general purpose.

IS-1886

Code of practice for installation and maintenance of transformers.

IS-2026 Power Transformers

IEC-76

IS-2099 Bushings for alternating voltage above 1000 V

IEC-137, BS-223

IS-2147 Degree of protection provided by enclosures for low voltage switchgear & control gear

IS-2705 Current Transformers IEC-185 IS-3203 Code of practice of climatic proofing of

electrical equipments.

IS-3347 Dimension for porcelain Transformer Bushings. IS-3401 Silica gel. IS-3637 Gas operated relays IS-3639 Fittings & Accessories for power transformers IS-4253 Cork and rubber. IS-5561 Electric Power Connector IS-5578 IS-11353

Marking & arrangements for Switchgear Bus bars, Main connections and auxiliary wiring.

IS-6272 Industrial cooling fans IS-6600 Guide for loading of oil immersed transformers BSCP-0160 IS-9434 Guide for sampling and analysis of dissolved

gas in oil filled equipments

IS-12676 Oil impregnated paper insulated Bushing Dimension and requirements.

Insulation Co-ordination.

IEC-71

Indian Electricity Rules, 1956

2.3 The standards mentioned above are available from:

Standard Name and address IS BUREAU OF INDIAN STANDARDS

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Manak Bhawan, 9, Bahadur Shah Zafar Marg, New Delhi 110 001 INDIA

IEC INTERNATIONAL ELECTROTECHNICAL COMMISSION Bureau Central de la Commission Electro Technique International, 1,Rue de Verembe, Geneva, SWITZERLAND

2.4 Equipment meeting with the requirements of other authoritative International

standards that ensure equal or better performance than the standards mentioned above shall also be considered. When the equipment offered by the supplier conforms to other standards, salient points of difference between standards adopted and the standards specified in this specification shall be clearly brought out in the offer. Two copies of such standards with authentic translation in English shall be furnished along with the offer.

3.0 AUXILIARY POWER SUPPLY

Auxiliary electrical equipment shall be suitable for operation on the following supply system: -

a) Power Devices 415 V, 3 Phase 4 wire like drive motors 50 Hz, neutral grounded AC supply.

b) Lighting, space heaters 240 V, single phase, and fractional kW motors. 50 Hz neutral grounded AC supply c) Alarm, control 110/220 V DC, 2 wire and protective devices

Each of the foregoing supplies shall be made available by the purchaser at the terminal point of each transformer for operation of accessories and auxiliary equipment. Supplier's scope include supply of interconnecting cables, terminal boxes etc. The above supply voltage may vary as below and all devices shall be suitable for continuous operation over entire range of voltages.

i) AC supply : Voltage +/-10% frequency +/- 5% ii) DC supply : - 15 % to +10% 4.0 PRINCIPAL PARAMETERS

The transformer shall conform to the PRINCIPAL TECHNICAL PARAMETERS indicated in Annexure ‘A’. Bidder should fill in & submit the Guaranteed Technical Parameters indicated in Annexure - B along with the technical bid.

5.0 DUTY REQUIREMENTS

5.1.1. The power transformer shall be suitable to be used for bi-directional flow.

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5.1.2. OLTC shall be provided on HV neutral end for HV compensation. For dual ratio

transformers, the primary winding is required to be suitable for operation at 132 KV or 110 KV/100KV, as per the purchaser's system requirement, it is desired to have series parallel arrangement in the H.V. winding for change over from 110KV/100 KV to 132 KV. For this purpose link board shall be provided inside the tank or in a separate chamber as the case may be for one time change over to 132 KV in future. The compensating winding with series-parallel arrangement shall be provided at the neutral end after the OLTC tapping windings. The main winding towards HV terminal shall remain unaltered for 110KV/100KV or 132 KV. The HV winding shall be insulated as 145 KV class winding. With this arrangement the complete HV winding will be in service irrespective of whether the transformer is operating at 110KV/100KV or 132 KV. Further, no appreciable change is expected in HV/LV impedance in the two cases.

5.1.3. The transformer and all its accessories like (bushing / neutral) CTs etc. shall be

designed to withstand without injury, the thermal and mechanical effects of any external short circuit to earth and short circuits at the terminals of any winding for a period of 2 sec. The short circuit level of the EHV (Primary) system to which the subject transformer will be connected shall be considered 40kA (Symm, rms, 3 phase fault) for design purpose. Transformer shall be capable of withstanding thermal and mechanical stress caused by symmetrical or asymmetrical faults on any winding.

5.1.4. The transformer shall be capable of being loaded in accordance with IS: 6600 clause

4 (a) up to loads of 150%. There shall be no limitation imposed by bushings, tap changer etc.

5.1.5. The transformer shall be capable of being operated without danger on any tapping at

the rated MVA with voltage variation of +/- 10% corresponding to the voltage of that tapping.

5.1.6. Radio interference and Noise Level:

i) The transformers shall be designed with particular attention for suppression of

maximum harmonic voltage, especially the third and the fifth so as to minimize interference with communication circuits.

ii) The noise level, when energized at normal voltage and frequency with fans running shall not exceed, when measured under standard conditions, the values specified in NEMA, TR-1.

5.1.7 Transformer shall be capable of operating under the natural cooled condition up to

the specified load. The forced cooling equipment shall come into operation by preset contacts of winding temperature indicator and the transformer shall then operate as a forced cooled unit, as ONAF up to specified load. Cooling shall be so designed that during total failure of power supply to cooling fans, the transformer shall be able to operate at full load for at least ten (10) minutes without the measured winding hot spot temperature exceeding 140 0C. Also stopping of one or two cooling fans should not have any effect on the cooling system. Transformers fitted with two coolers each capable of dissipating 50 percent of the heat at continuous maximum rating shall be capable of operating for 20 minutes in the event of failure of the oil circulating pump

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or blowers associated with one cooler, without the measured winding hot spot temperature exceeding 140 0C at continuous maximum rating.

5.1.8 Transformer shall withstand, without injurious heating the following, combined base

voltage and frequency fluctuation, which produces over fluxing condition: i) 125% for 1 minute) Base voltage and frequency refers to ii) 140% for 5 seconds) those mentioned in Principal Technical Parameters (at Cl. No. 4) 5.2 CAPITALIZATION OF LOSSES 5.2.1 For the purpose of cost evaluation, the capitalized cost of maximum guaranteed loss

of transformer quoted by the bidder shall be loaded in the F.O.R. destination price of the transformer as per the formula given below.

Capitalization of losses = 247608 Wi + 101016 Wc + 99048 Wp

(in Rs.)

Where

Wi = Maximum Iron losses in KW Wc = MaximumLoad losses in KW Wp = Maximum Auxillary losses in KW

5.2.2 Penalty Charges

The penalty charges shall be payable by the supplier to the purchaser in the event of losses and auxiliary consumption measured on the transformer after manufacturer exceeds guaranteed losses quoted by bidder in the offer as per formula given below:

Penalty = 247608 Wei + 101016 Wec + 99048 Wep in Rs.

Where

Wei = Excess no load losses in KW (measured value – quoted value)

Wec = Excess load losses in KW (measured value – quoted value) Wep = Excess auxiliary consumption in KW (measured value – quoted value) 5.3 CLEARANCES

The overall dimensions of the transformer shall allow for sufficient clearances for installation in 132 KV Switchyard: The overall dimensions shall be such that the axial length of transformer from centerline of the bay to the edges (on both sides) of transformers will not exceed 4.0 meters.

5.4 CONSTRUCTIONAL DETAILS

The features and constructional details of power transformer shall be in accordance with the requirements stated hereunder:

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5.4.1 Tank and Tank Accessories 5.4.1.1 Tank

a) Tank shall be of welded construction and fabricated from tested quality low Carbon steel of adequate thickness.

b) All seams and those joints not required to be opened at site shall be factory welded and wherever possible they shall be double welded. After completion of tank construction and before painting, dye penetration test shall be carried out on welded parts of jacking bosses, lifting lugs and all load bearing members. The requirement of post weld heat treatment for tank/stress relieving parts shall be based on recommendations of BS: 5500 table 4.4.3.1

c) Tank stiffeners shall be provided for general rigidity and these shall be designed to prevent retention of water.

d) The transformer shall be of bell type tank construction with the joint at about

500 mm above the bottom of the tank. In case the joint is welded, it shall be provided with flanges suitable for repeated welding. The joint shall be provided with a suitable gasket to prevent weld splatter inside the tank. Proper tank shielding shall be done to prevent excessive temperature rise of the joint.

e) The tanks shall be designed to withstand:

i) Mechanical shocks during transportation. ii) Vacuum filling of oil.

iii) Continuous internal pressure of 35 kN/m2 over normal hydrostatic pressure of oil.

iv) Short circuit forces

f) Wherever possible the transformer tank and its accessories shall be designed without pockets wherein gas may collect. Where pockets cannot be avoided, pipes shall be provided to vent the gas into the main expansion pipes.

g) Adequate space shall be provided at the bottom of the tank for collection of

sediments. h) The base of each tank shall be so designed that it shall be possible to move

the complete unit by skidding in any direction without injury when using plates or rails.

i) Tank shields shall be such that no magnetic fields shall exist outside the tank.

They shall be of magnetically permeable material. If required impermeable shields shall be provided at the coil ends. Tank shield shall not resonate when excited at the natural frequency of the equipment.

j) Suitable guides shall be provided in the tank for positioning the core and coil

assembly.

k) Each tank shall be provided with: - i) Lifting lugs suitable for lifting the equipment complete with oil.

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ii) A minimum of four jacking pads in accessible position at 500 mm height to enable the transformer complete with oil, to be raised or lowered using hydraulic or screw jacks.

iii) Suitable haulage holes shall be provided. 5.4.1.2 Tank cover

a) The tank cover shall be sloped to prevent retention of rainwater and shall not distort when lifted.

b) At least two adequately sized inspection openings, one at each end of the

tank shall be provided for easy access to bushings and earth connections. The inspection covers shall not weigh more than 25 kg. The inspection covers shall be provided with two handles.

c) The tank covers shall be fitted with pockets at the position of maximum oil

temperature corresponding to MCR (Maximum Continuous Rating) for RTD Sensors and bulbs of oil and winding temperature indicators. It shall be possible to remove these sensors bulbs without lowering the oil in the tank.

d) Bushings, turrets, covers of inspection openings, thermometer pockets etc.

shall be designed to prevent ingress of water into or leakage of oil from the tank.

e) All bolted connections shall be fitted with weather proof, hot oil resistant

gasket in between for complete oil tightness. If gasket is compressible, metallic stops shall be provided to prevent over-compression.

5.4.2 Axles and Wheels

a) The transformers are to be provided with flanged bi-directional wheels and axles. These shall be so designed as not to deflect excessively to interfere with the movement of the transformer. Wheels shall be provided with suitable bearings, which shall be rust and corrosion resistant. Fittings for lubrication shall also be provided.

b) Suitable locking arrangement along with foundation bolts shall be provided

for the wheels to prevent accidental movement of transformer.

c) The wheels are required to swivel and they shall be arranged so that they can be turned through an angle of 90o when the tank is jacked up to clear of rails. Means shall be provided for locking the swivel movements in positions parallel to and at right angles to the longitudinal axis of the tank.

d) The rail track gauge shall be (1676 mm) along longer axis as well as along

shorter axis.

5.4.3 Anti Earthquake Clamping Device:

To prevent transformer movement during earthquake, clamping device shall be provided for fixing transformer to the foundation. The Bidder shall supply necessary bolts for embedding in the concrete foundation. The arrangements shall be such that

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the transformer can be fixed to or unfastened from these bolts as desired. The fixing of the transformers to the foundations shall be designed to withstand seismic events to the extent that a static coefficient of 0.3g, applied in the direction of least resistance to that loading will not cause the transformer or clamping devices as well as bolts to be over stressed.

5.4.4 Conservator Tank

a) The conservator tank shall have adequate capacity between highest and lowest visible levels to meet the requirement of expansion of the total cold oil volume in the transformer and cooling equipment from minimum ambient temperature to100oC. Conservator shall be with volumetric capacity at least 7.5 percent of a total volume of oil in the main tank of the transformer.

b) The conservator tank shall be bolted into position so that it can be removed

for cleaning purposes.

c) The conservator shall be fitted with magnetic oil level gauge with electrically insulated contact for low oil level alarm.

d) Conservator shall be provided in such a position as not to obstruct the

electrical connections to the transformer.

e) Separate conservator tank/compartment in the main conservator shall be provided for OLTC.

5.4.5 Oil Preservation System 5.4.5.1 Conservator shall be fitted with a dehydrating filter breather. It shall be so designed

that: a) Passage of air is through a dust filter and silica gel. b) Silica gel is isolated from atmosphere by an oil seal. c) Moisture absorption indicated by a change in colour of the tinted crystals can

be easily observed from a distance. d) Breather is mounted not more than 1200 mm above rail top level.

e) Minimum quantity of silica gel will be 1 kg for every 3500 lts of oil in the tank

5.4.5.2 The Bidder shall provide diaphragm type oil sealing system (Balloon technology) in

the conservator. The requirements of this system are given below:

a) In this system, contact of the oil with atmosphere shall be prohibited by using a flexible or nitride rubber reinforced with nylon cloth air cell.

b) Diaphragm used shall be suitable for continuous operation at a temperature

of 100 0C, to which transformer oil is likely to rise.

c) The connection of the air cell to the top of the conservator shall be by an air proof seal permitting entrance of air into the cell only.

d) The Diaphragm of the conservator shall withstand the vacuum during

installation and maintenance. Otherwise provision shall be made to isolate

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the conservator from main tank during vacuum by providing vacuum sealing valve in the pipe connecting main tank with the conservator.

5.4.6 Pressure Relief Device

Adequate number of pressure relief devices shall be provided at suitable locations. These shall be of sufficient size for rapid release of any pressure that may be generated in the tank and which may result in damage to the equipment. The device shall operate at a static pressure, which is less than the hydraulic test pressure of transformer tank. It shall be mounted directly on the tank. One set of electrically insulated contacts shall be provided for alarm/tripping at the recommended settings.

5.4.7 Buchholz Relay

A double float type Buchholz relay shall be provided to detect the gases formed in the transformer. All the gases evolved in the transformer shall get collected in this relay. The relay shall be provided with a test cock suitable for a flexible pipe connection for checking its operation and taking gas sample. A copper or stainless steel tube shall be connected from the gas collector to a valve located about 1200 mm above ground level to facilitate sampling, even when the transformer is in service. The device shall be provided with two electrically independent ungrounded contacts, one for alarm on gas accumulation and the other for tripping on sudden rise of pressure.

5.4.8 Temperature Indicator

Temperature measurement of Oil and windings shall be done using Fiber optic sensors, meeting following criteria:

1. System shall be with fiber optic sensors with, proven and rugged technology.

The probes shall be directly installed in each phase / winding of power transformer to measure the winding hotspot and top oil temperature. There will be minimum eight probes inside the transformer, out of which one probe should be installed in top of the transformer for the detection of top oil temperature.

2. The remaining Fiber optic probes shall be installed in each phase / winding at the hottest spots of each of the phase windings. The locations of the probe shall be proposed by the Manufacturer and locations finalized by agreement of the Purchaser

3. Probes shall be suitable to be completely immersed in hot transformer oil; they shall withstand exposure to hot Kerosene vapor during the transformer insulation drying process.

4. Temperature range of the system should be -30°C to +200°C & accuracy of ± 2°C with no recalibration required.

5. Probes shall be 200μm all silica, double PFA Teflon jacketed, Kevlar cabled fiber with perforated outer jacket to allow complete oil filling and white Teflon protective Helix wrap for improved visibility and mechanical strength.

6. A microprocessor based monitoring and recording unit shall be a part of the system. System should include analog outputs for each measurement channel. Temperature resolution of the analog outputs shall be ±0.1°C and the systems shall offer a user programmable temperature alarm outputs with 6 relays, alarm lights and controller system status indicators. All inputs and outputs of the

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system shall meet the requirements of surge test of IEEE C37.90.1-1989 in which a 3000 V surge is applied to all the inputs and outputs without permanent damage to the instrument.

7. The system shall be capable of retaining temperature data of 90 days at one (1) reading/minute and should retain max temperature of each channel until reset.

8. The manufacturer should submit data showing that the probes are located in the hottest Point of the winding

9. The Fiber optic cables are to be brought out of the main tank through tank wall penetrator feed through plate. The Feed through plate shall be welded on the Tank. The external fiber optic extension cable shall then be run to main control cabinet, routed inside the conduits with large bend radiuses.

10. The controller shall be housed in cooler control cubicle or in a separate box of IP56 class mounted on the transformer tank. The position shall be clearly indicated in the GA drawings.

11. Temperature Rise Test Measurements shall be made with the FO Thermometers. The equipment shall be operational during temperature tests and demonstrated during these tests. During probe verification, the hottest probes for each phase shall be identified, and temperature data for all probes recorded and reported in the test report.

12. For remote indications on RTCC panel output of 4 to 20 mA shall be made available.

5.4.9 Earthing Terminals

a) Two (2) earthing pads (each complete with two (2) Nos. tapped holes, M 10

bolts, plain and spring washers) suitable for connection to 75 x 10 mm grounding flat shall be provided, each at position close to the two (2) diagonally opposite bottom corners of tank.

b) Two earthing terminals suitable for connection to 50 x 6 mm galvanized steel flat shall also be provided on cooler, marshalling box and any other equipment mounted separately.

5.5 INSULATING OIL

a) Oil shall be procured separately by the purchaser. The tenderer shall furnish following information in his offer to enable the purchaser to place order/s for oil.

i) Required technical parameters of oil. ii) Quantity required for first filling of transformer.

iii) List of manufacturers of oil who are preferred by the tenderer for the transformers offered by them.

b) The supplier shall dispatch the transformer of rating 50 MVA and above

filled with Nitrogen or dry air. The Bidder shall take care of the weight limitation on transport and handling facility at site. Necessary arrangement shall be ensured by the supplier to take care of pressure drop of nitrogen during transit and storage till completion of oil filling during erection. A gas pressure-testing valve with necessary pressure gauge and adapter valve shall be provided.

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5.6 Core

a) The core shall be constructed from high-grade non-ageing cold rolled Super grain oriented silicon steel laminations.

b) The design of the magnetic circuit shall be such as to avoid static discharges,

development of short circuit paths within itself or to the earthed clamping structure and production of flux component at right angles to the plane of laminations, which may cause local heating.

c) The insulation of core to bolts and core to clamps plates shall be able to

withstand a voltage of 2 kV RMS for one minute.

d) Core and winding shall be capable of withstanding the shock during transport, installation and service and adequate provision shall be made to prevent movement of core and winding with respect to tank during these conditions.

e) All steel sections used for supporting the core shall be thoroughly sand

blasted after cutting, drilling and welding.

f) When bell type tank construction is offered, suitable projecting guides shall be provided on core-assembly to facilitate removal of tank.

g) Each core lamination shall be insulated with a material that will not deteriorate due to pressure and hot oil.

h) The supporting framework of core shall be so designed as to avoid presence of pockets, which would prevent complete emptying of the tank through drain valve or cause trapping of air during oil filling.

i) The maximum flux density in any part of the core and yoke at rated MVA, voltage and frequency at any tap shall not exceed 1.6 Tesla.

j) Adequate lifting lugs shall be provided to enable the core (with winding) to be lifted.

5.7 Windings

a) The supplier shall ensure that windings of the transformers are made in dust proof environment. The conductors shall be of electrolytic grade copper.

b) The insulation of transformer windings and connections shall be free from

insulating compounds which are liable to soften, ooze out, shrink or collapse or be catalytic and chemically active in transformer oil during service.

c) Coil assembly and insulating spacers shall be so arranged as to ensure free circulation of oil and to reduce the hot spot of the winding.

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d) The stacks of windings shall receive adequate shrinkage treatment before and after final assembly. Adjustable devices if necessary shall be provided for taking up possible shrinkage of coils if any, in service. The provision made in this respect shall be clearly brought out in the Bid.

e) The conductors shall be transposed at suitable intervals in order to minimize

eddy current and to equalize the distribution of current and temperature along the windings.

f) The windings shall be so designed that all coil assembly of identical voltage rating shall be interchangeable and field repairs to the windings can be added without special equipment.

g) Fiber optic Sensors shall be embedded in each phase of the winding. The sensors shall be located where the Temperature is the highest.

5.8 TERMINAL ARRANGEMENTS 5.8.1 Bushings

a) The electrical and mechanical characteristics of bushings shall be in accordance with IS:2099 and IS:3347 (Part-III/Section-I). Dimensions and requirements of condenser bushings shall be in accordance with IS 12676, 1989.

b) 245 kV and 145 kV bushings shall be oil filled condenser type & 36 KV

bushings shall be of porcelain. No arcing horns shall be provided on any bushing. Bushing shall be as per technical particulars furnished. Bushings of identical rating shall be interchangeable.

c) Condenser type bushings shall be provided with: -

i) Oil level gauge.

ii) Oil filling plug and drain valve if not hermetically sealed;

iii) Tap for capacitance/tan delta measurement.

d) When bushings have an under-oil end of re-entrant form, the pull – through lead shall be fitted with a gas bubble deflector.

e) Where turret type current transformers are specified, the bushings shall be removable without disturbing the current transformers.

f) Porcelain used in bushing manufacture shall be homogenous, free from laminations, cavities and other flaws or imperfections that might affect the mechanical or dielectric quality and shall be thoroughly vitrified, tough and impervious to moisture. Glazing of porcelain / bushing shall be of uniform brown color and free from blisters, and burrs.

g) Special precaution shall be taken to eliminate moisture from paper insulation during manufacture, assembly, transport and erection of condenser bushings.

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h) Bushing turrets shall be provided with vent pipes that shall be connected to route any gas collection through the Buchholz relay.

5.8.2 Terminal Connectors

a) Bushing terminals shall be provided with terminal connectors of approved type and size for connection to external parts. Terminal connectors should have been successfully type tested strictly as per IS: 5561.

i) All connections with ACSR conductors shall be crimping type.

ii) Connectors shall be of electrolytic grade copper, forged and silver plated/tinned.

iii) No part of a clamp shall be less than 10 mm thick.

iv) Non-magnetic stainless steel nuts, bolts and plain washers shall be

used. Nuts and bolts shall have hexagonal head with threads as per IS and shall be fully threaded type. Instead of spring washers, check/lock nuts shall be provided.

v) The connectors shall be designed for minimum 120% of the maximum

current carrying capacity of the ACSR conductor and the temperature rise under these conditions shall not be more than 50% of that of the main conductor.

5.8.3 Bushing current transformers

a) Current transformers shall comply with IS: 2705.

b) It shall be possible to remove turret mounted CTs from the transformer tank without removing the tank cover. Necessary precaution shall be taken to minimize the eddy currents and local heat generated in the turret.

c) All secondary leads shall be brought to a terminal box near each bushing.

These terminals shall be wired up to the Cooler Control Cabinet using separate cables for each core/phase.

d) Bushing CT parameters indicated in the specification are tentative and liable

to change within reasonable limits. The Bidder shall obtain the Purchaser's approval before proceeding with design of Bushing CTs.

5.8.4 Terminal Marking

The terminal marking and their physical position shall be in accordance with IS: 2026 unless otherwise specified.

5.9 NEUTRAL EARTHING ARRANGEMENT

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a) The neutral terminals of the star connected windings shall be brought to the ground level by a copper grounding bar which shall be supported from the tank by porcelain insulators of highest system voltage of 24 KV.

b) The end of the copper bar shall be brought to the ground level, at a convenient point, for connection to the purchaser's ground network through two (2) 50x6 mm copper flats. The connection shall be made by using two (2) bolted neutral grounding terminals with necessary accessories.

c) Suitable flexible copper strip connection of adequate size shall be provided for connecting to Neutral Bushing terminals to avoid tensile load on the Bushings.

5.10 AUXILIARY POWER SUPPLY FOR OLTC, COOLER CONTROL AND POWER CIRCUIT

5.10.1 Auxiliary Power Supplies shall be as indicated in clause 3.0 and will be provided

by the purchaser at any one place for OLTC Control and Cooler Control. 5.10.2 All loads shall be fed by one of the two feeders through an electrically interlocked

automatic changeover scheme housed in any one of the local control cabinets for tap changer control and cooler circuits.

5.10.3 Design features of the changeover scheme shall include the following:

i) Provision for the selection of one of the feeders as normal source and the other as standby.

ii) Upon failure of the normal source, the loads shall be automatically

transferred, after an adjustable time delay, to the standby source. iii) Indication for ‘failure of normal source’ and for ‘transfer to standby source’

and also for ‘failure to transfer’ shall be provided in the local cubicle as well as in RTCC panel.

iv) Automatic re-transfers to normal source with an adjustable time delay

following re-energization of the normal source.

v) Both the transfer and the re-transfer shall be ‘dead transfers’ and AC feeders shall not be paralleled at any time.

vi) Necessary isolating switches, MCBs and other components for the above

power supply transfer arrangement shall be provided by the supplier. 5.11 TAP CHANGING EQUIPMENT

5.11.1 TAP CHANGER SWITCH (GENERAL REQUIREMENT):

a) For 50 MVA, , the OLTC shall be of the In Tank, Hi Speed, Resistor Type.

On-load tap changer shall be provided at the HV neutral end.

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b) OLTC gear shall be motor operated for local as well as remote electrical operation. An external hand wheel/handle shall be provided for local manual operation.

c) On load tap changer shall be sourced from reputed manufacturer and it

should be type tested as per relevant IEC 60214 including switching and transient resistance test of the relevant switch and test methods shall be in full conformance to the procedures indicated in IEC 60214.

5.11.2 On Load Tap Changing Gear (OLTC)

The details of the method of diversion of the load current during tap changing; the mechanical construction of the gear and the control features for OLTC gear shall be submitted with the bid. Information regarding the service experience, of the gear and a list of important users shall be furnished. The tap changer shall change the effective transformation ratio without producing phase displacement and shall meet the following requirements:

a) The current diverting contacts shall be housed in a separate oil chamber

not communicating with the oil in main tank of the transformer. For 50 MVA On load tap changer shall have maximum rated through current of 500Amps to meet the normal rated load as well as over load as per standards. The OLTC should also be suitable for an occasional switching at 200% of the OLTC Rating as per IEC 60214 which shall be validated with by the type test. The OLTC shall have BIL rating corresponding to 72.5 kV class and short circuit withstand current as per relevant IEC standards but not less than 8 kA for 3 seconds.

b) The contacts shall be accessible for inspection without lowering oil level in

the main tank. The contact tips shall be replaceable.

c) The supplier shall indicate the safeguards provided in order to avoid harmful arcing at the current diverting contacts in the event of operation of the OLTC gear under over-load conditions of the transformer.

d) The OLTC oil chamber shall have oil filling and drain plug, oil sampling

valve, and relief vent and oil level indicating glass. It shall also be fitted with a Surge relay, the outlet of which shall be connected to a separate conservator tank.

e) The diverter switch or arcing switch shall be so designed as to ensure that its

operation once commenced shall be completed independently of the control relays or switches, failure of auxiliary supplies etc.

f) Tap changer shall be so mounted that bell cover of transformer can be lifted

without removing connections between windings and tap changer.

g) Drive mechanism chamber shall be mounted on the tank in an easily accessible position. It should be adequately ventilated and provided with anti- condensation metal clad heaters. All contactors, relay coils and

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other parts shall be protected against corrosion, deterioration due to condensation, fungi etc.

h) Each transformer unit shall be provided with a local control cabinet and a

remote OLTC Control panel .The control feature shall provide the following:

i) Local-remote selector switch mounted in the local control cubicle shall switch control of OLTC in the following manner:

i) When the selector switch is in LOCAL position, it shall be possible to

operate the RAISE / LOWER control switch specified in section (iii) below. Remote control of RAISE/LOWER functions shall be prevented under this (local) condition.

ii) When the selector switch is in REMOTE, the local control cubicle

mounted RAISE/ LOWER switches specified in Section (iii) shall be inoperative. Remote control of the raise/lower function shall be possible from the remote control panel. The LOCAL-REMOTE selector switch shall have at least two spare contacts per position which are closed in that position but open in the other position.

iii) A RAISE/LOWER CONTROL SWITCH shall be provided in Local

Control Cubicle. The switch shall be spring loaded to return to the center 'OFF' position and shall require movement to the RIGHT to raise the voltage of the transformer. Movement to the left shall lower the voltage. This switch shall be operative only when ‘local remote', selector switch is in ‘local’ position.

iv) Operating mechanism for on load tap changer shall be designed to go through one step or tap change per command. Subsequent tap changes shall be initiated only on receipt of a new or repeat command. This should be ensured through Snap Action Mechanism in the Drive Mechanism

v) On-load tap changer shall be equipped with a time delay for "INCOMPLETE STEP" alarm consisting of a normally open contact which closes, if the tap changer fails to make a complete tap change. The alarm shall not operate for momentary loss of auxiliary power.

vi) The resistor based potentionmetric unit shall be installed in the local

OLTC control cabinet to provide tap position indication for the transformer. The supplier shall also provide a spare set of instruments as per clause for tap position indication on the RTCC panel in the control room. Complete mounting details shall be included with approved diagram.

vii) The OLTC shall be equipped with a fixed resistor network capable of providing discrete voltage steps for input to the supervisory system.

j) Limit switches shall be provided to prevent over-running of the mechanism

and shall be directly connected in the circuit of the operating motor. In addition, a mechanical stop shall be provided to prevent over-running of the

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mechanism under any condition. Limit switches may be connected in the control circuit of the operating motor provided that a mechanical-de- clutching mechanism is incorporated.

k) Thermal device or other means shall be provided to protect the motor and

control circuit. All relays, switches, MCBS etc. shall be mounted in the drive mechanism chamber and shall be clearly marked for the purpose of identification.

l) A permanently legible lubrication chart shall be fitted within the driving

mechanism chamber. m) A five-digit counter shall be fitted to the tap changing equipment to indicate

the number of operations completed. n) All relays and operating devices shall function correctly at any voltage

between the limits specified. o) It shall not be possible to operate the electric drive when the manual

operating gear is in use. p) OLTC Shall have a mechanical fuse incorporated in the design to ensure the

protection of divertor switch in the event of an undue mechanical stress on Tap Changer.

q) It shall not be possible for any two controls (i.e. manual, local electrical and

remote) to be in operation at the same time. r) The Tap Selector Contacts shall not be of the threaded type to ensure

positive, full face and firm contact from Transformer leads to Tap Changer. s) The equipment shall be suitable for supervisory control and indication with

make-before-break multi-way switch, having one potential free contact for each tap position. This switch shall be provided in addition to any other switch/switches, which may be required for remote tap position.

t) All electrical control switches and the local operating gear shall be clearly

labeled in a suitable manner to indicate the direction of tap changing. OLTC make proposed shall have proven record of installed population in similar ratings of not less than 3 years.

u) No continuity break shall be allowed during changeover between any two

taps. The OLTC shall be tested for the same by ensuring that there is no open circuit showing while changing two taps.

v) OLTC design should have been seismic tested and qualified. w) OLTC manufacturer shall conduct the following routine tests fully in

compliance with IEC 60214 on every unit, as given below, before dispatch to assure the quality of the product.

Sl. IEC Reference Test Description Acceptance level

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No. 01 60214 Cl. No. 5.3.1 Mechanical

Endurance Test Minimum 1000 operations

02.. 60214 Cl. No.5.3.2 Sequence Test Switching operation with timing less than 50 m.sec.

03. 60214 Cl. No.5.3.4 Pressure Test 10 PSI (0.7kg/sq.cm) for 8 hrs at room temperature.

04. 60214 Cl. No.5.3.4 Vacuum test Vacuum level as guaranteed by manufacturer.

05. Special Test Gas Tightness Test Helium based or any other mutually agreed method.

06. 60214 Cl. No.5.3.4 Auxiliary Circuits Insulation Tests.

Should withstand 2kV relative to earth for 1min

07. Special Test Contact resistance test

< 2 milliohms

08. Special Test Physical and dimensional Checks

As per approved drawing .

All the relevant test reports shall be submitted alongwith the test report of transformer for MSETCL’s approval.

x) The Tap Changer shall be suitably protected through Oil Surge Relay and it shall be of reed magnetic switch type. This surge relay shall be tested for an Oil flow velocity of 1.20 +/- 0.20 m/s.

5.11.3 Manual Control

The cranking device for manual operation of the OLTC gear shall be removable and suitable for operation by a man standing on ground level. The mechanism shall be complete with the following:

i) Mechanical tap position indicator which shall be clearly visible from near

the transformer.

ii) A mechanical operation counter. iii) Mechanical stops to prevent over-cranking of the mechanism beyond the

extreme tap positions. iv) The manual control, considered as back up to the motor operated tap

changer control, shall be interlocked with the motor to block motor-start-up during manual operation. The manual operating mechanism shall be labeled to show the direction of operation for raise / lower.

5.11.4 a) Electrical Control This includes the following: i) Local Electrical control. ii) Remote Electrical control from Remote Tap Changer Cubicle (RTCC)

b) Remote Electrical Group Control

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The OLTC control scheme offered shall have provision of remote electrical group control during parallel operation of transformers. This is in addition to independent control of OLTC.

i) A four position selector switch having MASTER, FOLLOWER,

INDEPENDENT and OFF position shall be provided in the remote OLTC control panel for each transformer. This shall be wired to enable operator to select operation of OLTC in Master, Follower or Independent mode.

ii) Out of step relays with timer contacts shall also be provided to give alarm

and indication in case of tap positions in all the transformers under group control being not in identical position.

iii) Master Position

If the selector switch is in MASTER position, it shall be possible to

control the OLTC units of other parallel connected transformers in the FOLLOWER mode by operating the controls of the MASTER unit. Independent operation of the units under FOLLOWER mode shall have to be prevented. However, the units under independent mode will be controlled independently.

iv) Follower Position

If the selector switch is in FOLLOWER mode, control of OLTC shall be possible only from the RTCC panel that is selected as MASTER.

v) Independent Position

In this position of Selector Switch, Control of OLTC of individual unit only shall be possible.

5.12 COOLING EQUIPMENT AND ITS CONTROLS 5.12.1 i) Cooling Equipment

a) Cooler shall be designed using 2x50% radiator banks. The radiator shall preferably be provided on both sides of the transformer main tank.

b) Each radiator bank shall have its own cooling fans, shut off valves, lifting

lugs, top and bottom oil filling valves, air release plug, a drain valve and thermometer pocket fitted with captive screw cap on the inlet and outlet.

c) One standby fan for each group shall also be provided and identified with

each radiator bank. d) Cooling fans shall not be directly mounted on radiator bank which may cause

undue vibration.

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e) The exhaust air flow from cooling fan shall not be directed towards the main tank in any case.

f) Cooling fans for each radiator bank shall be located so as to prevent ingress

of rain water. Each fan shall be suitably protected by galvanized wire guard. g) Cooling fans shall be suitable for operation from 415 volts, three phase 50

HZ power supply and shall conform to IS: 325. h) The cooler and its accessories shall be hot painted with corrosion resistant

paint. i) Each cooling fan shall be provided with starter, thermal overload and short

circuit protection. j) Each radiator shall be provided with: - One shut off valve at the top (80 mm size) - One shut-off valve at the bottom (80 mm size) - Air release device at the top. - Main & sampling device at the bottom. - Lifting lugs.

- Expansion joints, one each on top and bottom cooler pipe connections. - Air release device and oil plug on oil pipe connections.

5.12.2 Cooling Equipment Control (ONAN/ONAF COOLING)

a) Automatic operation control (switching in and out) of fans shall be provided (with temperature change) from contacts of winding temperature indicator. The supplier shall recommend the setting of WTI for automatic change over of cooler control from ONAN to ONAF. The setting shall be such that hunting i.e. frequent start/stop operations for small temperature differential do not occur.

b) Suitable manual electrical (non-auto) control facility for cooler fans with

manual/automatic selector switches and push buttons shall be provided.

5.12.3 Microprocessor based Numerical RTCC Unit for Tapchanger Control & Transformer Monitoring

Microprocessor based technology has been envisaged for the control of forced cooling equipment, condition monitoring and OLTC control of transformers.

Tenderers shall provide full description of the control system offered and details of deviations from specified requirement shall be brought out in the offer alongwith necessary justifications. The intent of this section is to describe the desired functional and environmental requirements in respect of microprocessor based Intelligent Transformer Control System (ITCS) without limiting the additional features that the tenderer may be able to include in the offer. The TCS should provide facilities such as SCADA links, transformer cooler control and data logging, control of the OLTC, remote OLTC tap

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position indication in digital form at local and the remote temperature indications for windings and top oil, temperature alarms and trip, marshalling of other control and alarm functions, emergency overload control, recording of accumulated “use of life” local display of status of control and alarm functions and selection of local and remote control etc. The TCS equipment (other than HMI and microprocessor unit) shall be located within the auxiliary marshalling cubicle and the Man Machine Interfacing (MMI) unit in the transformer RTC control panel in the control room.

a) FUNCTIONS:

i) Monitoring:

The TCS shall be capable of monitoring the analog data and status signals of the following:

Transformer LV load, voltage, tap changer status including tap position, tap changing in progress, status of control switches, OLTC motor current, OLTC motor trip, temperature difference between OLTC compartment and main tank. Temperature and condition of the transformer cooler status including top oil temperature, ambient temperature, winding hot spot temperature, run status of cooler fans and, fan trip, Interface with the fibre optic thermometer where fibre optics probe have been specified. This data shall be available for display, data logging and remote communication. For each analog value the TCS shall display the present and minimum and maximum value reached since the last time that the minima and maxima where reset to the current values. ii) Cooling Control:

The TCS shall be capable of controlling all cooling systems of the transformer including fans. The control function shall operate in such a way as to keep the transformer temperature within the limit set by the Purchaser.

The TCS shall be capable of : Predictive mode to turn on the cooling system based on predicted top oil and winding hot spot temperatures in addition to normal control based on actual temperatures. This should work in the event of a sudden sustained increase in load current, before the temperatures had risen to normal control settings, so as to keep the transformer cooler longer. Predicted temperature shall be based on a thermal model of each specific transformer ( based on actual heat run tests), ambient temperature and load. Periodic automatic testing : It shall be possible to automatically exercise testing of the cooler system at preset intervals to ensure that they are still functional, with an alarm if the test fails.

iii) OLTC Control:

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The control shall include selection of the following operating modes and features as applicable, by push buttons or keys at the controller or from SCADA. Manual OLTC control by pushbuttons or keys at the controller or from SCADA. AVR (automatic voltage regulation) Independent mode Master or follower parallel mode Circulating current parallel mode VAR sharing parallel mode Reverse reactance parallel mode AVR time delay shall be settable with definite time, fast – tap – down and inverse-time modes. AVR shall have the option of Line Drop Compensation (“LDC”). AVR shall be blocked, if the voltage drops below the under voltage set points, to prevent false operation in the event of supply line faults, VT fuse failure etc. OLTC operations shall be blocked if the current though the OLTC exceeds a preset value.

iv) Performance Calculations and Prediction:

The TCS shall be capable of calculating – Watts and VARs Accumulated number of tap changers from each tap position (discrete counter for each position) and total number of tap changers. Winding hot spot temperatures for each winding and maximum achieved. Winding hot spot insulation ageing rate (per unit) Accumulated insulation ageing (use of life) based on the winding hot spot (years) as per the loading guide for oil immersed power transformer. The use of life calculations shall also convey to the operator the amount of time available at the present over load rating and the amount of overload available for two hours duration from the time in question. Accumulated operating hours for each fan group. Accumulated number of starts for each fan group.

v) Alarms:

Alarms shall be extended to the SCADA system for : Voltage out of range for too long (AVR mode only) Voltage exceeds over-voltage alarm setting or is less than under-voltage alarm setting. OLTC auxiliary power failure OLTC fail (tap changed in progress too long or OLTC motor trip) Temperature abnormalities such as high oil temperature and high winding temperature. Top oil or winding hot spot temperature exceeds alarm settings. Top oil or winding hot spot temperature exceeds trip or stage to alarm settings Cooler auxiliary power failure Cooler fail (contactor failed to close when switched on, or motor trip, or oil flow failed)

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All OLTC and temperature trip signals shall be provided by means of voltage free contacts where the contacts have a rating of not less than 0.4A at 125 VDC resistive. All other trip signals such as Buchholz, pressure relief and OLTC surge shall be provided directly from the voltage free contacts of the respective device, not via the TCS. The alarms can however be wired via the TCS.

vi) Data Logging and Even Recording:

Monitored data shall be time and date stamped and logged in a format, which can be easily imported to data analysis software such as MS Excel/Access. The local data storage capability which can store all data at one minute intervals shall be stated by the tenderer. A separate event record is required to record the date and time (to nearest second) when the status of any alarm changes. The number of events that can be stored shall be stated by the tenderer. vii) Communication:

The TCS shall accept all Analogue / Digital quantities relevant to the control of the transformer or as required by the purchaser. These quantities shall be able to be interfaced to the purchaser’s SCADA equipment. The ITCS shall be capable of down loading data files via telephone line and GSM System. The protocol for communication shall be as per IEC 61850.

viii) Other capabilities:

Tenderers may also offer TCS which performs both Dissolved Gas Analysis and moisture in oil condition monitoring.

b) MAN MACHINE INTERFACE:

Access to control variables within the TCS shall be available to the personnel as required by the purchaser. The form of these interface should preferably be via a permanent front panel that contains a display and keypad. The menu facilities shall be as simple and intuitive as possible. Facilities to access the TCS via local RS-232 port and software running on a laptop PC under the latest version of Windows shall also be provided. A sample of the PC software shall be supplied to the purchaser for evaluation before proceeding with that method. Software supplied to the purchaser is not returnable and becomes the property of the purchaser.

c) ELECTRICAL ISOLATION AND TRANSIENT PERFORMANCE: All equipment shall be type tested, tested during manufacture and after completion of manufacturer in accordance with latest IEC 60255 and IEC 60068. a) POWER SUPPLIES: The TCS should be powered directly from the Sub-station battery bank.

b) INPUTS / OUTPUTS

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c) Digital Input and Output Modules

The “on” state of all digital inputs and outputs shall be indicated by Light Emitting Diodes (LED) on the front of the modules. These LEDs shall be visible from the front panel on which the TCS equipment is mounted. All inputs shall be electrically isolated from the external circuit and capable of being driven from 42 V dc to 240 V dc. All output shall be electrically isolated from external circuit and rated for switching 42 V dc to 240 V dc and 0.5 Amp. d) Communication ports: Communication ports shall be provided for the following – Connection to a local computer for down loading data files, uploading settings, software upgrade etc. Communication with SCADA RTU. Connection to a dial-in modem for down loading data files uploading settings, software upgrade etc. Communication with sensors and other auxiliary equipment. Serial communication with remote via a fibre optic links Connection to LAN to WAN or Intranet.

e) SELF-MONITORING: The TCS shall have a self-check of power on and shall continually monitor all functions and the validity of all input values to make sure the control system is in a healthy condition. In the event that the unit is unable to control the transformer, the device is to revert to a fail-safe condition. Any monitoring system problem shall initiate an alarm. f) MEMORY RETENTION: The TCS shall be capable of retaining its information in the event of a power failure. g) REAL TIME CLOCK: There shall be real time clock for time stamping the data log and event records. A long life battery shall be provided to keep the clock operating in the event of the power failure. An alarm shall be generated if the battery fails. It shall also be possible to synchronize the TCS clock with GPS system provided at the substations. h) SECURITY: Levels of security to limit access to authorized uses shall be provided for Viewing data and down loading data files (no access control) Changing control mode and manual control operations (password control) Changing settings and configuration (password control) Software upgrade (password control)

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i) MOUNTING: The TCS input/output modules /units shall be mounted within the auxiliary marshalling cubicle or in a separate cubicle with a similar construction located on the transformer. The cubicle shall be rated to IP56. The cubicle shall be capable of protecting the equipment contained within and keep it in operational condition at all times given the conditions described in the environmental section. The Man Machine Interface (MMI) unit will be mounted on the transformer Tap changer control panel in the control room. Cabling between the MMI unit and input / output modules / unit shall be supplied by the Purchaser. Any special cable if required, the details of the same shall be furnished. It shall be possible to have a second MMI mounted in the transformer control cubicle if required.

5.12.4 Cooler control cabinet

i) Each transformer unit shall be provided with a cooler control cabinet having a protection class IP56 or better.

ii) The cooler control cabinet shall have all necessary devices meant for

cooler control and local temp. Indicators. All the contacts of various protective devices mounted on the transformer shall also be wired up to the terminal board in the cooler control cabinet. All the secondary terminals of the bushing CTs shall also be wired up to the terminal board at the cooler control cabinet.

iii) The cooler control cabinet shall have two (2) sections. One section shall have

the control equipment exclusively meant for cooler control. The other section shall house the temperature indicators, and the terminal boards meant for termination of various alarm and trip contacts as well as various bushing CT secondaries. Alternatively, the two sections may be provided as two separate cubicles / kiosks, depending on the standard practices of the supplier.

iv) The temperature indicators shall be so mounted that the displays are not more

than 1600 mm from ground level Glass door of suitable size shall be provided for convenience of reading.

v) Controller of the Fiber optic Temperature Indicator shall be housed inside the

Cooler control cabinet or in a separate enclosure having degree of protection IP56.

5.12.5 Valves

1) All valves upto and including 100 mm size shall be of gun metal or of cast steel/cast iron. Larger valves may be of gun metal or may have cast iron bodies with gun metal fittings. They shall be of full way type with internal screw and shall open when turned counter clock wise when facing the hand wheel.

2) Suitable means shall be provided for locking the valves in the open and

close position. Provision is not required for locking individual radiator valves.

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3) Each valve shall be provided with the indicator to show clearly the

position of the valve. 4) All valve flanges shall have machined faces. 5) All valves in oil line shall be suitable for continuous operation with

transformer oil at 100ºC. 6) The oil sampling point for main tank shall have two identical valves to be

put in series. Oil sampling valve shall have provision to fix rubber hose of 10mm size to facilitate oil sampling.

7) A valve or other suitable means shall be provided to fix the on line

dissolved gas monitoring system to facilitate continuous dissolved gas analysis. The location and size of the same shall be finalized during detail engineering stage.

8) Suitable valves shall be provided to take sample of oil from the OLTC

chamber during operation of the transformer. 9) After testing, inside surface of all cast iron valves coming in contact with

oil shall be applied with one coat of oil resisting paint/varnish with two coats of red oxide zinc chromate primer followed by two coats of fully glossy finishing paint conforming to IS:2932 and of a shade (preferably red or yellow) distinct and different from that of main tank surface. Outside surface except gasket setting surface of butterfly valves shall be painted with two coats of red oxide zinc chromate conforming to IS:2074 followed by two coats of fully glossy finishing paint.

10) All hardware used shall be cadmium plated/electro galvanized.

5.13 TERMINAL BLOCK

i) The terminal block shall be stud type. The terminal blocks should be as per

IEC 60947/7-1. The insulating material should be polyamide and all the metal parts should be non ferrous. The screws should be captive and terminal should be shock protected. All terminal shall be clearly marked with identification numbers or letters to facilitate connection to external wiring.

ii) All internal wiring to be connected to the external equipment shall be

terminated on terminal blocks, preferably vertically mounted on the side of each panel. The terminal blocks shall be 800 V grade and have 10 amps continuous rating, moulded one piece, complete with insulated barriers, non-disconnecting stud type terminals, washers, nuts and lock nuts. Terminal block design shall include a white fiber-marking strip with clear plastic, slip-on/clip-on terminal cover. Markings on the terminal strips shall correspond to wire number and terminal numbers on the wiring diagrams.

iii) Terminal blocks for current transformer secondary leads shall be provided

with test links and isolating facilities. Also current transformer secondary leads shall be provided with short-circuiting and earthing facilities.

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iv) At least 20% spare terminals shall be provided on each cubicle and these

spare terminals shall be uniformly distributed on all terminal blocks. v) Unless otherwise specified, terminal blocks shall be suitable for connecting

the following conductors on each side.

a) For all circuits except current transformer circuits: minimum of two nos. of 2.5 mm2 copper.

b) For all CT circuits: minimum two nos. of 4 mm2 copper.

vi) There shall be a minimum edge-to-edge clearance of 250 mm between the

first row of terminal block and the associated cable gland plate. Also the clearance between two rows of terminal blocks shall be minimum 150 mm.

vii) Arrangement of the terminal block assemblies and the wiring channel within

the enclosure shall be such that a row of terminal blocks is run parallel and in close proximity along each side of the wiring duct to provide for convenient attachment of internal panel wiring. The side of the terminal block opposite the wiring duct shall be reserved for the owner's external cable connection. All adjacent terminal blocks shall also share this field-wiring corridor. A steel strip shall be connected between adjacent terminal block rows at 450 mm intervals for support of incoming cables.

5.14 PAINTING

The internal and external surfaces including oil filled chamber and structural steel work to be painted shall be shot or sand blasted to remove all rust and scale or foreign adhering matter or grease. All steel surfaces in contact with insulating oil shall be painted with two coats of heat resistant, oil insoluble, insulating varnish. All steel surfaces exposed to weather shall be given a primary coat of zinc chromate, second coat of oil and weather resistant varnish of a color distinct from primary coat. Two coats of glossy oil and weather resisting Olive Green paint in accordance with shade no.220 of IS-5 shall be given finally. All paints shall be carefully selected to withstand extremes of weather. The paint shall not scale off or crinkle or be removed by abrasion during normal handling. The minimum thickness of outside painting of tank shall be 20 microns and the total thickness shall be minimum 80 microns.

5.15 BOLTS AND NUTS

All bolts and nuts exposed to weather shall be hot dip galvanized. Bolts and nuts below M12 (12mm) size shall be stainless steel.

5.16 WIRING AND CABLING 5.16.1 a) Cable box/sealing end shall be suitable for the following types of cables:-

i) 415 Volt power : 1100 Volt grade PVC insulated aluminium conductor cable with armour.

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ii) Control : 1100 Volt grade PVC insulated 7/0.737 mm copper conductor cable with armour.

b) Compression type cable connector (lugs) shall be provided for termination of power and control cables.

c) All controls, alarms, indicating and relaying devices provided with the transformer shall be wired up to the terminal blocks inside the Local Control Cabinets (both Cooler and OLTC Control Cabinets.)

d) All devices and terminal blocks with the Cooler Control Cabinet shall be clearly

identified by symbols corresponding to those used on applicable schematic or wiring diagrams.

e) Not more than 2 wires shall be connected to one terminal. Each terminal shall

be suitable for connecting two nos. of 7/0.737 mm stranded copper conductors from each side.

f) All internal wiring shall be securely supported, neatly arranged, readily accessible

and connected to equipment terminals and terminal blocks.

g) Engraved code identification (plastic) ferrules marked to correspond with schematic diagrams shall be fitted at both ends of wires. Ferrules shall fit tightly on wires and shall not fall off when the wire is disconnected from terminal block.

5.16.2 EXCLUSION IN SCOPE OF CABLING:

Following cabling works are specifically excluded from the scope of the supplier. However, interconnection drgs. for the same are to be submitted by the supplier.

i) Cabling between Remote OLTC Panel/Microprocessor based Numerical

RTCC Unit for Tapchanger Control & Transformer Monitoring and the Cooler Control Cabinet.

ii) Cabling between Remote OLTC/Microprocessor based Numerical RTCC

Unit for Tapchanger Control & Transformer Monitoring panel and the Local OLTC Cabinet.

iii) Cabling between Remote OLTC/Microprocessor based Numerical RTCC

Unit for Tapchanger Control & Transformer Monitoring panels for Master/Follower operation.

iv) Cabling between Cooler Control Cabinet and Owner’s Auxiliary supply

panels.. v) Cabling between Local OLTC Cabinet and cooler control cubicle.

vi) All cabling between transformer MK (FCC) to the Owner's transformer C&R Panels.

5.17 FITTINGS

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The following fittings shall be provided with each transformer covered in this

specification. The bidder shall indicate the make, type & quantity of the following items.

a) Conservator for main tank, with oil filling hole and cap, isolating valves, drain valve, magnetic oil level gauge with low oil level alarm contacts and dehydrating breather: Buchholz relay, double float type, with isolating valves on both sides, bleeding pipe with petcock at the end to collect gases and alarm and trip contacts

b) Conservator for OLTC with drain valve, Buchholz (Oil Surge) relay, filling hole with prismatic oil level gauge and dehydrating breather.

c) Oil preservation equipment. d) Pressure relief device with alarm contacts. e) Air release plug. f) Inspection openings and covers g) Bushing with metal parts and gaskets to suit the termination arrangement. h) Oil temperature indicators. i) Covers lifting eyes, transformer lifting lugs, jacking pads, towing holes and

core and winding lifting lugs. j) Protected type mercury (or alcohol) in glass thermometer. k) Bottom and top filter valves with threaded male adaptors, bottom sampling

valve and drain valve. l) Rating and diagram plates on transformers and auxiliary apparatus. m) Earthing terminals. n) Flanged bi-directional wheels. o) Cooler Control Cabinet. p) On load tap changing equipment and OLTC control cabinet. q) Cooling equipment. r) Drain valves/plugs shall be provided in order that each section of pipe work

can be drained independently. s) Bushing CTs. t) Insulating oil. u) Terminal marking plate. v) Jacking pads. w) Lifting bollards. x) Haulage lugs. y) Cover Lifting lugs. z) Valve schedule plate. aa) Microprocessor based numerical RTCC Panel. ab) Temperature Indicator compatible with SCADA ac) Fibre optic based temperature measuring system complete ad) Transformer monitoring cum tap changer controller

Note: The fittings listed above are only indicative and any other fittings that generally are required for satisfactory operation of the transformer are deemed to be included.

5.18 LIMITS OF TEMPERATURE RISE

The temperature rise on any part of equipment shall not exceed the maximum temperature rise specified below under the conditions specified in test clauses. The permissible temperature rise indicated is for a maximum ambient temperature of 500

32

C. If the maximum ambient temperature rises, permissible values shall be reduced accordingly.

Maximum Value of Sl. No

Nature of the Part or of the liquid Temp. Temp. rise at a max.

ambient air temp. not exceeding 500C.

Contacts in air, silver-faced copper, copper alloy or aluminum alloy (see notes (i) and (ii)).

105 55/50 1

Bare copper or tinned aluminum alloy. 75 25

Contacts in oil: a)Silver-faced copper, copper alloy or aluminum alloy (see note ii)

90 40 2

b) Bare copper or tinned aluminum alloy 80 30

3 Terminals to be connected to external conductors by screws or bolts, silver faced (see note iii)

105 55

4 Metal parts acting as springs (See note iv)

(See note iv)

Metal parts in contact with insulation of the following classes:

Class Y: (for non-impregnated materials)

90 40

Class A: (for materials immersed in oil or impregnated)

100 50

Class E: in air in oil

120 100

70 50

Class B: in air in oil

130 100

80 50

Class F: in air in oil

155 100

105 50

5

Enamel: oil base synthetic, in air synthetic, in oil

100 120 100

50 70 50

6 Any part of metal or of insulating material in contact with oil, except contacts

100 50

7 Oil 90 40

Notes: i) When applying the temperature rise of 55/50 0C, care should be taken

to ensure that no damage is caused to the surrounding insulating materials.

ii) The quality of the silver facing shall be such that a layer of silver remains at the points of contact after the mechanical endurance test. Other wise, the contacts shall be regarded as "bare". iii) The values of temperature and temperature rise are valid whether or not

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the conductor connected to the terminals is silver-faced. iv) The temperature shall not reach a value where the elasticity of the material is impaired. For pure copper, this implies a temperature limit of 75 0C.

5.19 SPECIFICATION FOR CONTROL CABINETS:

a) Control cabinets shall be of the freestanding, floor-mounting type. b) Control cabinet of the operating mechanism shall be made out of 3mm thick

sheet steel or 10mm thick aluminum plate or casting. Hinged door shall be provided with padlocking arrangement. Sloping rain- hood shall be provided to cover all sides. 15mm thick neoprene or better type of gaskets shall be provided to ensure degree of protection of at least IP55 as per IS: 2147. The color of paint shall be Olive Green in accordance with shade no 220 of IS 5.

c) Bus bars shall be of tinned copper of adequate cross section to carry the

normal current, without exceeding the permissible temperature rise over an ambient temperature of 50 0C outside the cubicle. The bus bars shall be braced to withstand forces corresponding to short circuit current of 25 kA.

d) Fan Motors & Motors rated 1 kW and above being controlled from the

control cabinet shall be suitable for operation on a 415 V, 3 phase 50 Hz systems.

e) Isolating switches shall be group-operated units (3 pole for use on 3 phase

supply systems and 2 pole for single phase supply systems). The contacts shall be quick make quick break type, capable of breaking safely and without deterioration, the rated current of the associated circuit. Switch handle shall have provision for locking in both fully open and fully closed positions.

f) Push button shall be rated for not less than 6 Amps, 415 V A.C. or 2 Amps,

220V/110V D.C. and shall be flush mounted on the cabinet door and provided with appropriate nameplates.

g) For motors up to 5 kW, contactors shall be direct-on- line, air break, single

throw type and shall be suitable for making and breaking the starting current of the associated motor which shall be assumed to be equal to 6.5 times the full load current of the motor at 0.2 p.f. For motors above 5 kW, automatic star /delta type starters shall be provided. 3-pole contactors shall be provided for 3-phase motors and 2-pole contactors for single-phase motors. Reversing contactors shall be provided with electrical interlocks between forward and reverse contactors. If possible, mechanical interlocks shall also be provided. Contactors shall be suitable for uninterrupted duty and shall be of duty category class AC4 as defined in IS: 2959. The main contacts of the contactors shall be silver-plated and the insulation class for the coils shall be class E or better. The dropout voltage of the contactors shall not exceed 70% of the rated voltage.

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h) Contactors shall be provided with a three element. Positive acting, ambient temperature compensated, time lagged, hand reset type thermal overload relay with adjustable setting. Hand reset button shall be flush with the front door of the cabinet and suitable for resetting with starter compartment door closed.

i) Single phasing preventer relay shall be provided for 3 - phase motors to

ensure positive protection against single phasing.

j) Mini starters shall be provided with no- volt coils whenever required.

k) Purchaser's power cables will be of 1100/650 volts grade. PVC insulated/ PVC sheathed single steel wire armoured and PVC jacketed .All necessary cable terminating accessories such as glands, crimp type tinned copper lugs etc. for power as well as control cables shall be included in Bidder’s scope of supply. Suitable brass cable -glands shall be provided for cable entry.

l) Wiring for all control circuits shall be carried out with 1100/650 volts grade

PVC insulated tinned copper stranded conductors of size not smaller than 2.5 mm2. At least 20% spare terminal blocks for control wire terminations shall be provided on each panel. The terminal blocks shall be of non-disconnecting stud type .All terminals shall be provided with ferrules indelibly marked or numbered and these identifications shall correspond to the designations on the relevant wiring diagrams. The terminals shall be rated for adequate capacity, which shall not be less than 10 Amps.

m) Separate terminal blocks shall be provided for terminating circuits of various

voltage classes. CT leads shall be terminated on a separate block and shall have provision for short-circuiting the CT secondary terminals.

n) Control cabinet shall be provided with 240 V, 1- phase 50 Hz, 20 W

fluorescent light fixture and a suitably rated 240 V, 1 phase, 5 amps, 3 pin socket for hand lamps.

o) Strip heaters shall be provided inside each cabinet complete with thermostat

(preferably differential type) to prevent moisture condensation. Heaters shall be controlled by suitably rated double-pole miniature Circuit Breakers.

p) Signal lamps provided shall be of LED type with series resistors, enclosed in

bakelite body. q) Items inside the cabinet made of organic material shall be coated with a

fungus resistant varnish. 5.20 MOTORS:

Motors shall be "Squirrel Cage” type three / single phase induction motors of sufficient size capable of satisfactory operation for the application and duty as required for the driven equipment. Motors shall conform to IS 325

5.21 SPECIAL TOOLS AND TACKLES

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The Bidder shall include in his proposal any special erection and maintenance tools required according to the specialties of the Equipment. The list of such special tools shall be furnished in the offer and price of these shall be included in the proposed price.

5.22 SPARE PARTS AND MAINTENANCE EQUIPMENT 5.22.1 The Tenderer shall quote separately for mandatory spares specified at Annexure B1

for the transformer. 5.22.2 The make and types of spares offered shall be same as those offered along with the

main transformer. 5.22.3 Prices of these mandatory spares shall be taken into consideration for the purpose of

Bid evaluation. The purchaser shall decide the actual quantities of mandatory spares to be included in the order. These mandatory spares if ordered shall be supplied within six months from the date of order for the mandatory spares.

5.22.4 Bidder shall also indicate in his proposal optional spares required for the trouble free

operation of the equipment for five (5) years. Prices of these optional spares shall not be taken into consideration for the purpose of Bid evaluation. The purchaser shall decide the actual quantities of these optional spares to be included in the order. The optional spares if ordered shall be supplied within six months from the date of order for the optional spares.

6.0 TESTS

a) The transformer offered shall be fully type and special tested. In case the transformer offered has not been type and special tested in last 5 years as on the date of submission of offers, these tests shall have to be carried out by the successful bidder without any extra cost before commencement of supply. The purchaser reserves the right to demand repetition at purchaser's cost of some or all the type and special tests. Type and special tests to be carried out are listed hereunder.

b) The supplier shall carry out all type tests and routine tests on the transformers as

per the relevant standard. Type tests and special tests shall be carried out on one-transformer and routine tests on all transformers. Additional tests required to be carried out are also listed hereunder.

6.1 ROUTINE TESTS

All standard routine tests in accordance with IS:2026, with dielectric tests corresponding to Method 2 as per amendment No.1 issued in September,1980 to IS:2026 shall be carried out on each transformer. Operation and dielectric testing of OLTC shall be carried out as per IS: 2026 Clause no.16.9

Following additional routine tests shall also be carried out on each transformer:

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a) Magnetic Circuit Test After assembly, each core shall be tested for 1 minute at 2000 Volts between all bolts, side plates, and structural steel work.

b) Oil leakage test on transformer tank as per details given in this Clause subsequently. c) Magnetic balance test. d) Measurement of no-load current with 415V, 50 Hz a.c. supply on LV side. e) Frequency response analysis (FRA). f) High voltage withstand test shall be performed on auxillary equipment and

wiring after complete assembly. 6.2 TYPE TESTS Following type tests shall be conducted on one transformer of each rating: a) Temp-rise test as per IS: 2026 (Part-I).

The temperature rise test shall be conducted at extreme tap corresponding to maximum temperature rise. In case tested losses and / or quoted losses at extreme tap are more than the maximum losses specified at normal tap, the transformer shall be tested by feeding the tested losses or quoted losses whichever is higher. The supplier, before carrying out such tests, shall submit detailed calculations showing the alternatives possible on various taps and for the three different ratings (ONAN/ONAF) of the transformer and shall recommend the combination that results in highest temperature rise for the test.

Gas Chromatographic analysis on oil shall be conducted along with the test and the value shall be recorded in the test report. The sampling shall be in accordance with IEC-567. For the evaluation of the gas analysis in temperature rise test, a method will be proposed which is based on the rate of increase of particular gases and the permissible limits of minimum detectable value of gases. The maximum limit will be mutually discussed and agreed upon between the Owner and Supplier. This shall be treated as reference during future maintenance of the transformer.

Temperature Rise Test Measurements shall be made with the Fiber Optic Thermometers. The equipment shall be operational during temperature tests and demonstrated during these tests. During probe verification, the hottest probes for each phase shall be identified, and temperature data for all probes recorded and reported in the test report.

b) Tank vacuum test as per details given in this clause subsequently. c) Tank pressure test as per details given in this clause subsequently.

d) Pressure Relief Device Test:

The pressure relief device of each size shall be subjected to increase in oil pressure. It shall operate before reaching the test pressure specified in 'Tank tests' subsequently in this clause. The device shall seal off after the excess pressure has been released.

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e) Following special tests other than type and routine tests shall also be carried out as per IS: 2026 Part-I and Part-III as applicable on one unit of each type.

i) Measurement of zero sequence reactance as per CL.16.10 of IS : 2026. ii) Measurement of acoustic noise level as per Cl.16.12 of IS : 2026. iii) Measurement of power taken by fans. iv) Measurement of harmonic level in no load current.

v) Measurement of capacitance and tan delta to determine capacitance between winding & earth. This measurement shall be carried out before and after series of electric tests.

vi) Lightning impulse with chop on tail on all 3 - phases of HV and LV for

terminals as per IS 2026 (Part III) vii) Measurement of transferred surge on LV winding due to HV lightning

impulse.

f) One Cooler Control Cabinet and OLTC cabinet of each type of transformer shall be tested for IP: 55 protection in accordance with IS: 13947 (Part I) 1993.

g) Routine tests on bushings i) Test for leakage on internal fillings.

ii) Measurement of creepage distance, dielectric dissipation factor and capacitance. iii) Dry power frequency test on terminal and tapping. iv) Dry power discharge test followed by dielectric dissipation factor and

capacitance measurement.

h) Type Tests on fittings:

All the following fittings shall conform to type tests and the type test reports shall be furnished by the contractor along with the drawings of equipment/fittings as per the Clause No. 9.2 of the Section-GTR. The list of fittings and the type test requirement is: 1) Bushing (Type Test as per IS:2099/IEC:137). 2) Buchholz relay (Type Test as per IS:3637 and IP-55 Test on terminal

box). 3) OLTC (Temperature Rise of contact, Short circuit current test,

Mechanical test and Dielectric Test as per IEC:214 and IP-55 test on driving mechanism box).

4) Cooler Control Cabinet (IP-55 test). 5) Pressure Relief Device Test.

The pressure Relief Device of each size shall be subjected to increase in oil pressure. It shall operate before reaching the test pressure specified in transformer tank pressure test at Clause No.5.2.7.2 (ii) below. The

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operating pressure shall be recorded. The device shall seal off after excess pressure has been released. The terminal box / boxes of PRD should conform to degree of protection as per IP-55 of IS:13947.

6) Magnetic Oil Level gauge and terminal box for IP-55 degree of protection.

7) Air Cell (Flexible air separator) – Oil side coating, air side under coating, air side outer coating and coated fabric as per IS:3400 / BS:903 /IS:7016.

8) OTI and WTI – Switch setting and operation, switch differential, switch rating.

9) Cooling fan and motor assembly – Free air delivery, temperature rise, sound level, running at reduced voltage, IP-55 degree of protection for terminal box.

In case of manufacturers of foreign origin, reports for all the type test specified under clause No. 6.4.4 of this specification conducted internationally accredited laboratories (accredition based on ISO/IEC vide 25/17025 or EN 450001 by the National accredition body of the country where laboratory is located) or at the manufacturer’s work in presence of user’s representative can also be submitted alongwith the offer as evidence to establish the fulfillment of above requirement. However in such a case, all type tests as specified under clause No 6.4.4 of this specification shall be organized by the successful tenderer, after award of contract in presence of Purchaser’s representative, at the cost of bidder. The arrangement of to & fro journey of purchaser’s representative from his headquarter to place of testing shall be made by bidder at his (bidder’s) cost.

6.3 TANK TESTS a) Routine Tests Oil leakage test

All tanks and oil filled compartments shall be tested for oil tightness by completely filling with air or oil of a viscosity not greater than that of insulating oil conforming to IS: 335 at the ambient temperature and applying a pressure equal to the normal pressure plus 35 kN/m2 measured at the base of the tank. The pressure shall be maintained for a period of not less than 12 hours for oil and one hour for air during which time no leak shall occur.

b) Type Tests i) Vacuum Test

Where required by the Owner one transformer tank shall be subjected to the specified vacuum. The tank designed for full vacuum shall be tested at an internal pressure of 3.33 kN/m 2 absolute (25 torr) for one hour. The permanent deflection of flat plate after the vacuum has been released shall not exceed the values specified below.

Horizontal length of flat plate(in mm)

Permanent Deflection (in mm)

Up to and including 750 5

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751 to 1250 6.5

1251 to 1750 8

1751 to 2000 9.5

2001 to 2250 11

2251 to 2500 12.5

2501 to 3000 16

above 3000 19

ii) Pressure Test

Where required by the Owner, one transformer tank of each size together with its radiator, conservator vessel and other fittings shall be subjected to a pressure corresponding to twice the normal head of oil or to the normal pressure plus 35 kN/m2 whichever is lower, measured at the base of the tank and maintained for one hour. The permanent deflection of flat plates after the excess pressure has been released shall not exceed the figure specified above for vacuum test.

c) Pre-Shipment Checks and Manufacturer’s Works

1) Check for interchangeability of components of similar transformers for mounting dimensions.

2) Check for proper packing and preservation of accessories like radiators,

bushings, dehydrating breather, rollers, buchholz relay, fans, control cubicle, connecting pipes, conservator etc.

3) Check for proper provision for bracing to arrest the movement of core and

winding assembly inside the tank.

4) Gas tightness test to confirm tightness.

5) Derivation of leakage rate and ensure the adequate reserve gas capacity. 6.4 Inspection and Tasting at site

The Contractor shall carry out a detailed inspection and testing programme for field activities covering areas right from the receipt of material stage upto commissioning stage. An indicative programme of inspection as envisaged by the employer is given below and in the document No.OS/T&C/Bay/95 (Pre-commissioning Procedures and Formats for sub-station bay equipment), which will be available in the respective sites and shall be referred by the contractor. However, it is contractor’s responsibility to draw up and carry out such a programme duly approved by the employer. Testing of oil sample at site shall be carried out as per Clasue No. 3.4 above.

6.4.1 Receipt and Storage Checks. 6.4.1.1 Check and record condition of each package, visible parts of the transformer etc., for

any damage.

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6.4.1.2 Check and record the gas pressure in the transformer tank as well as in the gas cylinder.

6.4.1.3 Visual check for wedging of core and coils before filling-up with oil and also check

conditions of core and winding in general. 6.4.1.4 Check and record reading of impact recorder at receipt and verify the allowable

limits as per manufacturer’s recommendations. 6.4.2 Installation Checks 6.4.2.1 Inspection and performance testing of accessories like tap changers, cooling fans etc. 6.4.2.2 (i) Check the direction of rotation of fans.

(ii) Check the bearing lubrication. 6.4.2.3 Check whole assembly for tightness, general appearance etc. 6.4.2.4 Oil leakage test. 6.4.2.5 Capacitance and tan delta measurement of bushing before fixing/connecting to the

winding, contractor shall furnish these values for site reference. 6.4.2.6 Leakage test on bushing before erection. 6.4.2.7 Measure and record the dew point of nitrogen in the main tank before assembly. 6.4.3 Commissioning Checks: 6.4.3.1 Check the colour of silica gel in silica gel breather. 6.4.3.2 Check the oil level in the breather housing, conservator tanks, cooling system,

condenser bushing etc. 6.4.3.3 Check the bushing for conformity of connection to the lines etc. 6.4.3.4 Check for correct operation of all protection devices and alarms:

(i) Buchholz relay. (ii) Excessive winding temperature. (iii) Excessive oil temperature. (iv) Low oil flow. (v) Low oil level indication. (vi) Fan failure protection.

6.4.3.5 Check for the adequate protection on the electric circuit supplying the accessories.

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6.4.3.6 Check resistance of all windings on all steps of the tap changer. Insulation resistance measurement for the following:

(i) Control wiring. (ii) Cooling system motor and control. (iii) Main waindings.

(iv) Tap changer motor and control. 6.4.3.7 Check for cleanliness of the transformer and the surroundings. 6.4.3.8 Continuously observe the transformer operation at no load for 24 hours. 6.4.3.9 Gradually put the transformer on load, check and measure increase in temperature in

relation to the load and check the operation with respect to temperature rise and noise level etc.

6.4.3.10 Phase out and vector group test. 6.4.3.11 Ratio test on all taps. 6.4.3.12 Magnetizing current test. 6.4.3.13 Capacitance and tan delta measurement of winding and bushing. 6.4.3.14 DGA of oil just before commissioning and after 24 hours energisation at site. 6.4.3.15 Frequency response analysis (FRA). 6.4.3.16 Contractor shall prepare a comprehensive commissioning report including all

commissioning test results and forward to employer for future record.

6.4.4 SEQUENCE OF TESTS:

The sequence of type tests, special tests (whenever applicable) and routine tests required to be conducted on each transformer is as mentioned hereunder :

S NO. TEST

CATEGORY DESCRIPTION

1 Type Parameters as per drawings. 2 Type Tank pressure test with measurement of deflection.

3 Type Tank vacuum test with measurement of deflection 4 Type Pressure relief device test. 5 Type Degree of protection IP55 for OLTC & cooling control

cabinets. 6 Type Magnetic circuit insulation test 2KV - 1 Min. core to

Yoke clamp, core to flith plate, core bolt to Yoke 7 Type Oil DGA test (before and after HV & TR tests) 8 Type No load loss and current (before & after HV & TR

Routine tests) at 90% , 100% and 110% of rated voltage with 3W, 3A & 3V meters method.

9 Type Impulse test: One reduced full wave One full wave

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One reduced chopped wave Two full chopped wave Two full waves

10 11

Type Type

Temperature rise test at ONAN & ONAF ratings & quoted max. losses. ----- Repeat tests at sr. nos. 8,9,11,12, and 14 -----

12 Type Oil leakage test at 35 KN/m2 (0.357kg/sq.cm) over max. static head of oil measured at the base for 12 hrs.

13 Type Jacking test 14 Type Bushing current transformer ratio & polarity tests. 15 Routine Magnetic balance test at any one tap 16 Routine IR value at 10/60/600 sec (before & after HV & TR

Tests) 17 Routine Winding resistance at all taps. 18 Routine Oil BDV test (before and after HV & TR tests) 19 Routine Voltage ratio at all taps & polarity/phase displacement

at normal tap. 20 Routine Separate source voltage withstand test 21 Routine Induced over voltage withstand test 22 Routine Load loss at extreme taps & normal tap & impedance

at all taps by 3W, 3V, 3A meter method. 23 Routine Tests on OLTC:

1) Circuit insulation test 2 KV - 1 Min. 2) Operations tests: 8 Cy, 1 Cy at 85% V, 1 Cy at no load and rated V, 10 Cy +/- 2 steps from normal Tap and rated current.

24 Routine Cooling control test: 1) Circuit insulation test 2 KV- 1 Min. 2) Operation test.

25 Routine SFRA 26 Special Capacitance and tan delta (before & after HV & TR

tests.) at 5 KV & 10 KV: HV to LV + TANK; HV + LV to TANK under grounded and guarded specimen modes.

27 Special Harmonic analysis of no load current at 90%, 110% of rated V

28 Special Zero sequence impedance test at 10% / 20% / 60%/ 80% / 100% of test current at extreme taps and normal tap.

29 Special Acoustic noise level test. 30 Special Measurement of power consumption by fans

NOTE: 1) CT,PT, Ammeter, Voltmeter, Wattmeter, Frequency meter shall be of appropriate class of accuracy and shall have valid calibration certificate.

2) T.R – Temperature Rise Test. 6.4.5 The manufacturer shall carry out the Sweep Frequency Response Analysis (SFRA)

Test at their works and also during pre-commissioning at site. The values / data shall be furnished to MSETCL for future reference.

6.5 TEST REPORTS

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a) Six (6) sets of certified test reports and oscillograms shall be submitted for

approval prior to despatch of the equipment. The equipment shall be dispatched only when all the required type and routine tests have been carried out and test reports have been approved by the purchaser.

b) Four (4) copies of the test reports for the tests carried out on the auxiliary

apparatus shall be furnished to the purchaser for approval prior to dispatch. All auxiliary equipment shall be tested as per the relevant standard. Test certificate shall be submitted for bought out items.

6.6 Apart from rejection due to failure of the transformer to meet the specified test

requirements, the transformer shall be liable for rejection on account of any one of the following reasons.

a) No load loss exceeds the values mentioned in Principal Technical parameters of

this specification. (Cl. No. 4 Sr. no. 31) b) Load loss exceeds the specified values mentioned in Principal Technical

parameters of this specification. (Cl. No. 4 Sr. no. 32)

c) Impedance voltage value exceeds the Guaranteed value plus tolerances. 7.0 INSPECTION

i) The purchaser shall have access at all reasonable times to the works and all other places of manufacture where the transformers are being manufactured and the supplier shall provide all facilities for unrestricted inspection of the supplier's works, raw materials, manufacture of all the accessories and for conducting necessary tests.

ii) The supplier / Bidder shall keep the purchaser informed in advance of the

time of starting and of the progress of manufacture of equipment in its various stages so that arrangements could be made for stage inspection, if desired by purchaser / owner.

iii) No material shall be dispatched from its point of manufacture unless the material

has been satisfactorily inspected and tested.

iv) The acceptance of any quantity of equipment shall in no way relieve the supplier of his responsibility for meeting all the requirement of this specification and shall not prevent subsequent rejection if such equipment are later found to be defective.

v) The supplier shall inform the purchaser at least thirty days in advance,

about the manufacturing programme so that arrangement can be made for inspection.

vi) The purchaser reserves the right to insist for witnessing the

acceptance/routine testing of bought out items. The supplier shall communicate to the purchaser the details of such testing programme at

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least three weeks in advance. The testing shall not be postponed even if the purchaser is unable to depute his representative for witnessing the testing.

8.0 QUALITY ASSURANCE PLAN: 8.1 The Bidder shall invariably furnish the following information along with his offer,

failing which the offer shall be liable for rejection.

i) Statement giving list of important raw materials, names of sub-suppliers for the raw material, list of standards according to which the raw material are tested, list of tests normally carried out on raw material in the presence of the transformer manufacturer’s representative and copies of test certificates.

ii) Information and copies of test certificates as in (i) above in respect of bought out

items. iii) List of manufacturing facilities available.

iv) Level of automation achieved and list of areas where manual processing exists.

v) List of areas in manufacturing process, where stage inspections are normally carried out for quality control and details of such tests and inspections.

vi) Special features if any are provided in the equipment to make it maintenance

free. vii) List of testing equipment available with the transformer manufacturer for final

testing of equipment specified and test plant limitation, if any, vis-à-vis the type, special, acceptance and routine tests specified in the relevant standards. These limitations shall be very clearly brought out in "Schedule of Deviations".

8.2 The supplier shall within 30 days of placement of order, submit the following Information to the purchaser.

i) Descriptive list of the raw material as well as bought out accessories and the names of sub- suppliers selected from those furnished along with the offer.

ii) Type test certificates of the raw material and bought out accessories.

iii) Quality Assurance Plan (QAP) with hold points for purchaser’s inspection. The QAP and hold points shall be discussed between the purchaser and the supplier before the QAP is finalized.

8.3 The supplier shall submit the routine test certificates of bought out items and raw

material at the time of routine testing of the fully assembled equipment. 9.0 PERFORMANCE GUARANTEE:

The transformer shall be guaranteed for satisfactory performance for a period of 24 months from “ the date of commissioning “ or 30 months from the date of receipt at

45

site whichever is earlier. For the purpose of this guarantee, the delivery date is reckoned as the date of receipt of the last consignment of accessories/fittings in good condition at site/stores and also receipt of Operation, Maintenance & Erection Manuals at the office of the Chief Engineer, CRA, Department, Mumbai.

10.0 DOCUMENTATION: 10.1 All drawings shall conform to relevant International Standards Organization (ISO) specification. All drawings shall be in ink and suitable for microfilming. All dimensions and data shall be in S.I Units. 10.2 The Bidder shall furnish along with the bid dimensional drawings of Transformer,

and all other accessories. These drawings shall include the following information. a) Dimensions. b) Tolerances on dimensions.

c) Material designation used for different components with reference to standards.

d) Fabrication details such as welds, finishes and coatings.

e) Catalogue or part numbers for each component and the total assembly with bill of materials.

f) Identification marking.

g) Weight of individual components and total assembled weight.

h) Foundation drawing.

i) G.A. drawings of cooler control cabinet and RTCC panels.

j) Schematic drawings of OLTC, RTCC and cooler control.

10.3 The supplier shall, within 2 weeks of placement of order, submit three sets of final

version of all the above drawings for purchaser's approval. The purchaser shall communicate his comments/approval on the drawings to the supplier within reasonable period. The supplier shall, if necessary, modify the drawings and resubmit three copies of the modified drawings for purchaser's approval within two weeks from the date of comments.

10.4 The supplier shall also furnish three copies (per unit of transformer) to the office of

Chief Engineer, Tr. O&M. Department, Mumbai, of bound manuals covering erection, commissioning, operation and maintenance instructions and all relevant information and drawings pertaining to the main equipment as well as auxiliary devices. Marked erection drawings shall identify the component parts of the equipment as shipped to enable purchaser to carryout erection. Each manual shall also contain one set of all the approved drawings, type test reports as well as acceptance reports of the corresponding consignment dispatched. One set of good

46

quality reproducible of all approved and as-built drawings shall also be supplied for each rating of transformer.

10.5 The manufacturing of the equipment shall be strictly in accordance with the

approved drawings and no deviation shall be permitted without the written approval of the purchaser. All manufacturing and fabrication work in connection with the equipment prior to the approval of the drawing shall be at the supplier's risk.

10.6 Test Reports

i) Four copies of type test reports shall be submitted to the purchaser within one month of conducting the tests. One copy will be returned duly certified by the purchaser to the supplier within three weeks there after and on receipt of the same the manufacturer shall commence commercial production of the remaining similar units.

ii) Four copies of acceptance test reports shall be submitted to the purchaser. One

copy will be returned duly certified by the purchaser and only thereafter shall the materials be dispatched.

iii) All records of routine test reports shall be maintained by the supplier at his

works for periodic inspection by the purchaser. iv) All test reports for tests conducted during manufacture shall be maintained

by the supplier. These shall be produced for verification as and when requested for by the purchaser.

11.0 PACKING AND FORWARDING: 11.1 The equipment shall be packed in crates suitable for vertical/horizontal transport as

the case may be and suitable to withstand handling during transport and outdoor storage during transit. The supplier shall be responsible for any damage to the equipment during transit due to improper and inadequate packing. The easily damageable material shall be carefully packed and marked with the appropriate caution symbol. Wherever necessary, proper arrangement for lifting, such as lifting hooks etc. shall be provided. Any material found short / damaged inside the packing cases shall be supplied / made good by supplier without any extra cost to the purchaser.

11.2 Each consignment shall be accompanied by a detailed packing list containing the

following information: a) Name of the consignee b) Details of consignment c) Destination d) Total weight of consignment e) Sign showing upper/lower side of the crate. f) Handling and unpacking instructions. g) Bill of material indicating contents of each package. 11.3 The supplier shall ensure that the packing list / bill of material are approved by the

purchaser before despatch.

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12.0 TRAINING

The successful tenderer shall be required to impart in plant training, at no extra cost to the purchaser including to & fro charges, lodging & boarding etc, to at least five engineers to be nominated by the purchaser for a period of one week at his works, where the equipments offered shall be manufactured. The scope of the training shall cover assembly, factory testing, site testing, periodical maintenance, and operation and possible trouble shooting of the transformers. The owner reserves the right to depute all / any / no engineer for the training.

13.0 SUPERVISORY ERECTION AND COMMISSINING

The Tenderer shall quote the per day rates for the services of the Testing and Commissioning Engineer. The Tenderer are requested to quote lump sum charges inclusive of lodging, Boarding, T.A., D.A., other incidental charges etc. per Power Transformer for Supervision of only erection work of Power transformer and Inspection of erected Power transformer, testing and commissioning as under in given format. i) Charges for Supervision of erection work of Power Transformer and Inspection of erected Power Transformer, testing and commissioning in Rs./in $_______per day. Theses price shall not be considered for bid evaluation. The charges will be on firm price basis and valid for 2 years.

14.0 LIST OF MANDATORY SPARES

The bidder shall offer for one bushing of each class as a mandatory spares. 15.0 INFORMATION TO BE FILLED INVARIABLY BY THE TENDERER

For ready reference of the tenderer, the information required to be invariably furnished by the tenderer in his offer, are listed below:

Following information is to be submitted physically along with offer (Techno commercial bid).

i) GTP ii) List of type test conducted iii) Certificate of accreditation of the testing laboratory where the type test

are conducted. iv) Drawings, test certificate & documents as per Qualifying requirement

clause of this specification. v) Performance certificates vi) Type Test reports vii) Undertaking in the form of affidavit regarding CRGO as per clause no:

5.6(a) Offers without the above information or with incomplete information may be rejected.

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49

Annexure ‘A1’

PRINCIPAL TECHNICAL PARAMETERS

50MVA, 132/33 Power Transformer (YNyn0) 4.0 PRINCIPAL PARAMETERS

The transformer shall conform to the PRINCIPAL TECHNICAL PARAMETERS indicated as below.

SR. NO.

DESCRIPTION 50MVA, 132/33,

1. Type of power transformers/installation 3 Phase core type 2 winding T/F suitable for outdoor installation and suitable for bi-directional flow of power.

2. Type of mounting 0n wheels mounted on rails

3. Suitable for rated system frequency 50 Hz

4. a) Voltage Class 145 kv

b) Voltage Ratio 132/33KV.

5. No. of phases Three

6. No. of windings Two

7. Type of cooling ONAF

8. MVA rating corresponding to cooling system.

a) ONAN cooling 40

b) ONAF cooling 50

c) OFAF Cooling -

9. Method of connection

HV Star

IV -

LV Star

10. Connection symbol (Vector group) for all transformers YNynO

11. System earthing Effectively solidly Earthed

12. Percentage impedance, voltage on normal tap and at rated MVA with 10% tolerance applicable

a) HV-IV

b) HV-LV 10% on base MVA and 132/33kV ratio

13. Anticipated continuous loading of windings

a) HV and LV Not to exceed 110% of its rated capacity

b) Tertiary N.A.

14. Tap changing gear:

i) Type In Tank, Hi Speed Resistor Type, On-load.

ii) Provided on HV Neutral end for HV compensation

iii) Tap range +5% to -15%

iv) Step voltage 1.25% of 132KV

v) Rated voltage of on load Tap Changer. 72.5kV

vi) Rated current of on load Tap Changer. 500 Amps

50

vii) Short circuit withstand current and duration 8 kA for 3 seconds.

15. Over voltage operating capability and duration i) 125% of rated voltage for 60 seconds

ii) 140% of rated voltage for 5 seconds

16. Minimum Air Core reactance of HV windings 20%

17. Max.flux density in any part of core and yoke at rated MVA, normal voltage (Tesla)

1.6

18. Current density of HV/IV/LV windings Not exceeding 3 Amp. Per Sq.mm

19. Insulation levels for windings:

a) 1.2/50 micro- second wave shape impulse withstand (kVp) HV LV HV (N) 550 170 95

b) Separate source with stand voltage (kV rms) HV LV 38 70

c) Power frequency voltage withstand (kVp) HV LV 230 70

20. Type of winding insulation:

a) HV/IV winding Graded

b) LV winding Full

21. System short circuit level and duration for which the transformer shall be capable to withstand thermal and dynamic stresses (kA rms/sec)

40 KA for 2 seconds

22. Noise level at rated voltage and frequency As per latest NEMA std. Tr-1

23. Permissible temperature rise over ambient temp of 50 DC.

i) Of top oil measured by thermometer 400C

ii) Of winding measured by resistance 450C

24. Minimum clearance in air (mm)

a) HV

a) Phase to phase 1430

b) Phase to ground 1270

b) IV

a) Phase to phase -

b) Phase to ground -

c) LV

a) Phase to phase 800

b) Phase to ground 480

25. Terminals:

a) HV winding Line end 145KV class OIP condenser bushing

b) IV winding Line end NA

c) HV/IV/LV winding Neutral end 36 KV porcelain bushing.

d) LV winding 36 KV porcelain bushing

26. Bushing current rating

HV 800 Amp

IV/LV 2000 Amp

27. Max.Radio interference voltage level at 1MHZ & 1.1 times max. rms phase to ground voltage for HV Terminal connector.

500 Micro volts

28. Cooling Equipments:

a) Number of Banks. Tank mounted radiators .Two nos. of 50% bank.

b) No. of pumps N.A.

51

c) No. of Fans Adequate number of fans of 18"/24" sweep with one no. stand by fan in each group.

29. Insulation level of bushings.

a) Lightning impulse withstand (kVP) HV LV 650 170

b) Switching impulse withstand (kVP) N.A.

c) 1 Minute power frequency withstand voltage (kV rms) HV LV 270 70

d) Creepage distance (mm) 25 mm per KV for highest system voltage

30.a Bushing current transformers for purchaser’s use (for restricted E/F protection)

HV side bushings only

i) Type Single phase ring type turret mounted

ii) Current Ratio (A/A):(A/A) 400/1

iii) Knee point voltage (V) 600 V

iv) Accuracy class P.S.

v) Secondary resistance (Ohms) 5 Ohms

vi) Turns ratio Identical to the ratio provided on HV neutral.

vii) No. of cores 1

30b HV Neutral side CT for owner's use

i) Type Single phase ring type turret mounted

ii) Quantity 1

iii) Voltage class 24KV

iv) No. of cores 1

v) Current Ratios (A/A) 400/1

vi) Turn ratio Identical to the ratio provided on HV side

vii) Knee point voltage 600V.

viii) Class of accuracy

ix) Max.secondary winding resistance (rms) 5 Ohms

x) Location for mounting In neutral lead before connection to station earth.

31. Maximum no load loss (Iron loss) at rated voltage and at rated frequency at 75 D C in KW.

To be filled by the supplier in GTP

32. Maximum load loss including cooler loss because of consumption by the cooler fans, motor pump sets etc. at rated current and at rated frequency at 75 D C in KW.

To be filled by the supplier in GTP

Note:

HV: High voltage

IV :Intermediate voltage

LV: Low voltage

52

Annexure ‘A1’

PRINCIPAL TECHNICAL PARAMETERS

50MVA, 132-110/33KV Power Transformer (YNyn0) 4.0 PRINCIPAL PARAMETERS

The transformer shall conform to the PRINCIPAL TECHNICAL PARAMETERS indicated as below.

SR. NO.

DESCRIPTION 50MVA, 132-110/33 KV

1. Type of power transformers/installation 3 Phase core type 2 winding T/F suitable for outdoor installation and suitable for bi-directional flow of power.

2. Type of mounting 0n wheels mounted on rails

3. Suitable for rated system frequency 50 Hz

4. a) Voltage Class 145 kv

b) Voltage Ratio 132-110/33KV.

5. No. of phases Three

6. No. of windings Two

7. Type of cooling ONAF

8. MVA rating corresponding to cooling system.

a) ONAN cooling 40

b) ONAF cooling 50

c) OFAF Cooling -

9. Method of connection

HV Star

IV -

LV Star

10. Connection symbol (Vector group) for all transformers YNynO

11. System earthing Effectively solidly Earthed

12. Percentage impedance, voltage on normal tap and at rated MVA with 10% tolerance applicable

a) HV-IV

b) HV-LV 10% on base MVA and 132/33kV ratio

13. Anticipated continuous loading of windings

a) HV and LV Not to exceed 110% of its rated capacity

b) Tertiary N.A.

14. Tap changing gear:

i) Type In Tank, Hi Speed Resistor Type, On-load.

ii) Provided on HV Neutral end for HV compensation

iii) Tap range +5% to -15%

iv) Step voltage 1.25% of 132KV

v) Rated voltage of on load Tap Changer. 72.5kV

vi) Rated current of on load Tap Changer. 500 Amps

vii) Short circuit withstand current and duration 8 kA for 3 seconds.

53

15. Over voltage operating capability and duration i) 125% of rated voltage for 60 seconds

ii) 140% of rated voltage for 5 seconds

16. Minimum Air Core reactance of HV windings 20%

17. Max.flux density in any part of core and yoke at rated MVA, normal voltage (Tesla)

1.6

18. Current density of HV/IV/LV windings Not exceeding 3 Amp. Per Sq.mm

19. Insulation levels for windings:

a) 1.2/50 micro- second wave shape impulse withstand (kVp) HV LV HV (N) 550 170 95

b) Separate source with stand voltage (kV rms) HV LV 38 70

c) Power frequency voltage withstand (kVp) HV LV 230 70

20. Type of winding insulation:

a) HV/IV winding Graded

b) LV winding Full

21. System short circuit level and duration for which the transformer shall be capable to withstand thermal and dynamic stresses (kA rms/sec)

40 KA for 2 seconds

22. Noise level at rated voltage and frequency As per latest NEMA std. Tr-1

23. Permissible temperature rise over ambient temp of 50 DC.

i) Of top oil measured by thermometer 400C

ii) Of winding measured by resistance 450C

24. Minimum clearance in air (mm)

a) HV

a) Phase to phase 1430

b) Phase to ground 1270

b) IV

a) Phase to phase -

b) Phase to ground -

c) LV

a) Phase to phase 800

b) Phase to ground 480

25. Terminals:

a) HV winding Line end 145KV class OIP condenser bushing

b) IV winding Line end NA

c) HV/IV/LV winding Neutral end 36 KV porcelain bushing.

d) LV winding 36 KV porcelain bushing

26. Bushing current rating

HV 800 Amp

IV/LV 2000 Amp

27. Max.Radio interference voltage level at 1MHZ & 1.1 times max. rms phase to ground voltage for HV Terminal connector.

500 Micro volts

28. Cooling Equipments:

a) Number of Banks. Tank mounted radiators .Two nos. of 50% bank.

b) No. of pumps N.A.

54

c) No. of Fans Adequate number of fans of 18"/24" sweep with one no. stand by fan in each group.

29. Insulation level of bushings.

a) Lightning impulse withstand (kVP) HV LV 650 170

b) Switching impulse withstand (kVP) N.A.

c) 1 Minute power frequency withstand voltage (kV rms) HV LV 270 70

d) Creepage distance (mm) 25 mm per KV for highest system voltage

30.a Bushing current transformers for purchaser’s use (for restricted E/F protection)

HV side bushings only

i) Type Single phase ring type turret mounted

ii) Current Ratio (A/A):(A/A) 400/1

iii) Knee point voltage (V) 600 V

iv) Accuracy class P.S.

v) Secondary resistance (Ohms) 5 Ohms

vi) Turns ratio Identical to the ratio provided on HV neutral.

vii) No. of cores 1

30b HV Neutral side CT for owner's use

i) Type Single phase ring type turret mounted

ii) Quantity 1

iii) Voltage class 24KV

iv) No. of cores 1

v) Current Ratios (A/A) 400/1

vi) Turn ratio Identical to the ratio provided on HV side

vii) Knee point voltage 600V.

viii) Class of accuracy

ix) Max.secondary winding resistance (rms) 5 Ohms

x) Location for mounting In neutral lead before connection to station earth.

31. Maximum no load loss (Iron loss) at rated voltage and at rated frequency at 75 D C in KW.

To be filled by the supplier in GTP

32. Maximum load loss including cooler loss because of consumption by the cooler fans, motor pump sets etc. at rated current and at rated frequency at 75 D C in KW.

To be filled by the supplier in GTP

Note:

HV: High voltage

IV :Intermediate voltage

LV: Low voltage

55

Annexure-B

50 MVA, 132/33KV

Guaranteed Technical Parameters: 1 Name of the Manufacturer and country of origin

2 Conforming to standard

3 Service (Indoor/outdoor)

4 Ratings: With ONAN cooling-MVA

5 Ratings:With ONAF cooling-MVA

6 Rated no load voltage: HV, in KV

7 Rated no load voltage: LV, in KV

8 Temperature rise of top oil, in Deg. C

9 Temperature rise of winding measured by resistance : With ONAN cooling, in Deg. C

10 Temperature rise of winding measured by resistance : With ONAF cooling, in Deg. C

11 Period of operation of transformer at full load without calculated winding hot spot temperature exceeding 140 Deg. C with 50% cooler system not working (in minuites)

12

Period of operation of transformer at full load without calculated winding hot spot temperature exceeding 140 Deg. C with 100% cooler system not working (in minuites)

13 Rated frequecy (HZ)

14 No. of windings

15 Number of phases

16 Connection symbol & vector group

17 Tappings:-Type of tap changer

18 Tappings:-Tap step (percent)

19 Tappings:-Total tap range (+) percent to (-) percent

20 Tappings:-Tappings provided at

21 Magnetisation data at no load : Current in Amps

22 Magnetisation data at no load : Power factor

23 Magnetisation data at no load : Max. Loss in kW(core loss + dielectric loss)

24 Magnetisation data at no load : Max. flux density in lines/ sq. cm .at 100% rated no load voltage

25 Magnetisation data at no load : Max. flux density in lines/sq. cm. at 110% rated no load voltage.

26 Magnetisation data at no load : Max. flux density in lines/sq. cm at maximum rated primary voltage (i.e. 105% rated no load voltage)

27 Load loss at rated current at 75 Deg. C : For ONAN Rating, Cu loss, in KW

28 Max. Load loss including cooler loss at rated current at 75 Deg. C : For ONAF Rating, Cu loss + Cooler loss, in KW

29 Impedance at rated current and frequency at 75 Deg. C on rated MVA: At normal tap, in % (HV to LV)

30 Impedance at rated current and frequency at 75 Deg. C on rated MVA: At Max. voltage tap, in % (HV to LV)

31 Impedance at rated current and frequency at 75 Deg. C on rated MVA: At Min-voltage tap, in % (HV to LV)

32 Reactance at rated current and frequency and normal tap on rated MVA base :- HV to LV - in %

33 Resistance at 75 Deg. C of : HV Winding (in ohms)

34 Resistance at 75 Deg. C of : LV Winding (in ohms)

56

35 Efficiency at 75 Deg. C, taking into account input to cooling plant as loss : At 125% full load and unity p.f. - in %

36 Efficiency at 75 Deg. C, taking into account input to cooling plant as loss : At 100% full load and unity p.f - in %

37 Efficiency at 75 Deg. C, taking into account input to cooling plant as loss : At 75% full load and unity p.f - in %

38 Efficiency at 75 Deg. C, taking into account input to cooling plant as loss : At 50% full load and unity p.f. - in %

39 Efficiency at 75 Deg. C, taking into account input to cooling plant as loss : At 125% full load and 0.8 p.f. - in %

40 Efficiency at 75 Deg. C, taking into account input to cooling plant as loss : At 100% full load and 0.8 p.f. - in %

41 Efficiency at 75 Deg. C taking into account input to cooling plant as loss : At 75% full load and 0.8 p.f. - in %

42 Efficiency at 75 Deg. C taking into account input to cooling plant as loss : At 50% full load and 0.8 p.f. - in %

43 Maximum efficiency and load at which it occurs : At 125% full load (percent at percentage full load and p.f.) - in %

44 Maximum efficiency and load at which it occurs : At 100% full load (percent at percentage full load and p.f.) - in %

45 Maximum efficiency and load at which it occurs : At 75% full load (percent at percentage full load and p.f.) - in %

46 Maximum efficiency and load at which it occurs : At 50% full load (percent at percentage full load and p.f.) - in %

47 Regulation at full load & at 75 Deg. C : At Unity p.f.(lag), in %

48 Regulation at full load & at 75 Deg. C: At 0.8 p.f.(lag), in %

49 System short circuit level and duration for which the transformer shall be capable to withstand thermal and dynamic stresses (kA rms /sec)

50 Overload capacity for 2 hours after continuous full load run (Please mention temperature & MVA capacity as per IS 6600)

51 Thermal time constant, in hours

52 Test Voltages : Lightning impulse withstand, kV (Peak) (HV)

53 Test Voltages : Power frequency voltage withstand, kV(rms) (HV)

54 Test Voltages : Switching surge withstand, kV (peak) (HV)

55 Test Voltages : Lightning impulse withstand, kV (Peak) (LV)

56 Test Voltages : Power frequency voltage withstand, kV(rms) (LV)

57 Test Voltages : Switching surge withstand, kV (peak) (LV)

58 Partial discharge level at 364 kV as per IEC 44(4)

59 RIV at 1.1 times minimum phase to ground voltage (in micro Volts) .

60 Noise level when energized at normal voltage and normal frequency at no load, in db.

61 Approximate weight : Core (in Kg)

62 Approximate weight : Windings (in Kg)

63 Approximate weight : Tank & Fittings (in Kg)

64 Approximate weight : Oil (in Kg)

65 Approximate weight : Total weight (in Kg)

66 Approximate required quantity of oil, in Litres

67 Terminal connectors type and drawing no : HV

68 Terminal connectors type and drawing no : LV

69 Net core area in sq. metre

70 Type of transformer (Shell/Core)

71 Material of Laminations

57

72 Maximum flux density at rated voltage and frequency in lines/sq. cm

73 Type of joints between core limb and yoke

74 Conductor area in sq. cm and current density in Amp/sq. cm : HV

75 Conductor area in sq. cm and current density in Amp/sq. cm : LV

76 Type of Windings: HV

77 Type of Windings: LV

78 Winding insulation : HV : Type and Class/ Graded or Ungraded

79 Winding insulation : LV : Type and Class/ Graded or Ungraded

80 Insulating material : Turn Insulation : HV side

81 Insulating material :Turn Insulation : LV side

82 Insulating material : Between HV and LV

83 Insulating material : Between core & LV side 84 Insulating material : For core bolts, washers and end plates

85 Insulating material : Tapping connection

86 Type of axial support : HV winding

87 Type of axial support : LV winding

88 Type of Radial Coil Support :-HV winding

89 Type of Radial Coil Support :-LV winding

90 Details of special arrangement provided to improve surge voltage distribution in the windings

91 Clearance in oil between HV windings (in mm)

92 Clearance in oil between LV windings (in mm) 93 Clearance in oil between Ph. To Ground, HV windings (in mm)

94 Clearance in oil between Ph. To Ground, LV windings (in mm) 95 Clearance out of oil between HV windings (Ph. to Ph.) (in mm) 96 Clearance out of oil between LV windings (Ph. to Ph.) (in mm) 97 Clearance out of oil between Ph. To Ground, HV windings (in mm) 98 Clearance out of oil between Ph. To Ground, LV windings (in mm)

99 Details of Tank: Material for main tank

100 Details of Tank: Type of the tank

101 Details of Tank: Thickness of sides (in mm)

102 Details of Tank: Thickness of Bottom (in mm)

103 Details of Tank: Thickness of Cover (in mm)

104 Details of Tank: Thickness of Radiators (in mm)

105 Details of Painting at works and site

106 Minimum clear height for lifting bell and for lifting core and windings from tank (in mm) (Untanking height)

107 Shipping details :- Parts detached for transport

108 Shipping details :- Weight of heaviest package (kgs)

109 Shipping details :- Weight of other heavy packages (kgs. )

110 Shipping details :- Dimensions of largest package ( Length x Breadthx Hight) in mm

111 Dimensions of other heavy packages ( Length x Breadthx Hight) in mm

112 Details of HV Bushings: Type

113 Details of HV Bushings: Power frequency, visible corona discharge voltage, kV (rms.)

114 Details of HV Bushings:.One minute dry power frequency withstand voltage, kV (rms)

115 Details of HV Bushings: One minute wet power frequency withstand voltage, kV (rms)

58

116 Details of HV Bushings: Under oil Flashover or Puncture power frequency voltage, kV (rms)

117 Details of HV Bushings: 1.2/50 ms. lightning impulse withstand voltage, kV (peak)

118 Details of HV Bushings: Switching surge withstand voltage, kV(peak)

119 Details of HV Bushings: Under oil Flashover or puncture impulse voltage, kV(peak)

120 Details of HV Bushings: Creepage distance, in Air (mm)

121 Details of HV Bushings: Weight of assembled bushings (kg)

122 Details of HV Bushings: Phase to earth clearance in Air of live parts at the top of bushings,in mm

123 Details of HV Bushings: Maximum current rating of the bushings, in Amps.

124 Details of HV Bushings: Grade of oil in the bushings

125 Details of HV Bushings: Quantity of oil in the bushings, in Litres

126 Details of HVN Bushings: Type

127 Details of HVN Bushings: Power frequency, visible corona discharge voltage, kV (rms.)

128 Details of HVN Bushings:.One minute dry power frequency withstand voltage, kV (rms)

129 Details of HVN Bushings: One minute wet power frequency withstand voltage, kV (rms)

130 Details of HVN Bushings: Under oil Flashover or Puncture power frequency voltage, kV (rms)

131 Details of HVN Bushings: 1.2/50 ms. lightning impulse withstand voltage, kV (peak)

132 Details of HVN Bushings: Switching surge withstand voltage, kV(peak)

133 Details of HVN Bushings: Under oil Flashover or puncture impulse voltage, kV(peak)

134 Details of HVN Bushings: Creepage distance in Air (in mm)

135 Details of HVN Bushings: Weight of assembled bushings (in kg)

136 Details of HVN Bushings: HV Neutral Terminal to earth clearance in Air in mm

137 Details of HVN Bushings: Maximum current rating of the bushings, in Amps.

138 Details of HVN Bushings: Grade of oil in the bushings

139 Details of HVN Bushings: Quantity of oil in the bushings (Litres)

140 Details of LV Bushings: Type

141 Details of LV Bushings: Power frequency, visible corona discharge voltage, kV (rms.)

142 Details of LV Bushings:.One minute dry power frequency withstand voltage, kV (rms)

143 Details of LV Bushings: One minute wet power frequency withstand voltage, kV (rms)

144 Details of LV Bushings: Under oil Flashover or Puncture power frequency voltage, kV (rms)

145 Details of LV Bushings: 1.2/50 ms. lightning impulse withstand voltage, kV (peak)

146 Details of LV Bushings: Switching surge withstand voltage, kV(peak)

147 Details of LV Bushings: Under oil Flashover or puncture impulse voltage, kV(peak)

148 Details of LV Bushings: Creepage distance, in Air (mm)

149 Details of LV Bushings: Weight of assembled bushings (kg)

150 Details of LV Bushings: Phase to earth clearance in Air of live parts at the top of bushings, in mm

151 Details of LV Bushings: Maximum current rating of the bushings, in Amps.

152 Details of LV Bushings: Grade of oil in the bushings

59

153 Details of LV Bushings: Quantity of oil in the bushings, in Litres

154 Details of LV Neutral Bushings: Type

155 Details of LV Neutral Bushings: Power frequency, visible corona discharge voltage, kV (rms.)

156 Details of LV Neutral Bushings:.One minute dry power frequency withstand voltage, kV (rms)

157 Details of LV Neutral Bushings: One minute wet power frequency withstand voltage, kV (rms)

158 Details of LV Bushings: Creepage distance, in Air (mm)

159 Details of LV Bushings: Weight of assembled bushings (kg)

160 Details of LV Bushings: Phase to earth clearance in Air of live parts at the top of bushings, in mm

161 Details of LV Bushings: Maximum current rating of the bushings, in Amps.

162 Details of LV Bushings: Grade of oil in the bushings

163 Details of LV Bushings: Quantity of oil in the bushings, in Litres

164 Details of LV Neutral Bushings: Type

165 Details of LV Neutral Bushings: Power frequency, visible corona discharge voltage, kV (rms.)

166 Details of LV Neutral Bushings:.One minute dry power frequency withstand voltage, kV (rms)

167 Details of LV Neutral Bushings: One minute wet power frequency withstand voltage, kV (rms)

168 On Load Tap Changing gear : Make and Type

169 On Load Tap Changing gear : Rating: Rated voltage, in kV

170 On Load Tap Changing gear : Rating: Rated current Amps

171 On Load Tap Changing gear : Rating: Step voltage kV

172 On Load Tap Changing gear : Rating: No.of steps Nos.

173 On Load Tap Changing gear : Approximate over all dimensions (Width x Breadth x Depth) in mm

174 On Load Tap Changing gear : Approximate over all weight in kgs.

175 On Load Tap Changing gear : Approximate over all quantity of oil in litres

176 On Load Tap Changing gear : Time to complete one tap- change step, in seconds

177 Cooling System: Grade of Oil

178 Cooling System: Quantity of oil in Transformer (litres) 179 Cooling System: Weight of oil in Transformer( Kg)

180 Cooling System: Total radiating surface, in sq. metre

181 Cooling System: Method of drying out transformer at site

182 Cooling System: Type and make of material used for the radiators

183 Cooling System: Total number of Radiators/ Banks for transformer and dimensions of tubes

184 Cooling System: Total weight of Radiators (kg)

185 Cooling Equipment : Fan Motor: Make and Type (Details)

186 Cooling Equipment : Fan Motor: Number connected

187 Cooling Equipment : Fan Motor: Nos. in standby 188 Cooling Equipment : Fan Motor: Rated Power, in KW

189 Cooling Equipment : Fan Motor: Rating of driven equipment (kW)

190 Cooling Equipment : Fan Motor: Rated voltage (Volts) 191 Cooling Equipment : Fan Motor: Locked rotor current (Amps)

60

192 Cooling Equipment : Temperature over which control is adjustable

193 Overall dimensions of transformer including cooling gear, tap changing gear etc. (LengthX BreadthX Height), in mm

194 Overall dimensions of transformer: Reference drawing No. 195 Whether oil temperature indicator provided (Yes/No.)

196 Type and size of oil temperature indicator and whether supervisory alarm contacts provided

197 Type of oil level indicator and whether supervisory alarm contact for low oil level provided

198 Type and size of Gas operated relay and whether supervisory alarm and trip contacts provided and their ratings and Nos.

199 Whether winding temperature indicator with supervisory alarm and trip contacts provided (yes/no)

200 If winding temperature indicator with supervisory alarm and trip contacts provided, their sizes (lxbxd), in mm

201 If winding temperature indicator with supervisory alarm and trip contacts provided , their Nos

202 Ratio of C.T. used for winding temperature indicator :

203 Type of C.T. used for winding temperature indicator :

204 Type and size of thermostat used

205 No. of Breathers provided (No.)

206 Type of dehydrating agent used for breathers

207 Capacity of conservator vessel (Litres)

208 Drain valve size required/ fitted : in mm

209 Drain valves required/ fitted, in Nos.

210 Filter Valve size required/ fitted : in mm

211 Filter Valves required/ fitted : in Nos

212 Sampling valve size required/ fitted : in mm

213 Sampling valves required/ fitted : in Nos

214 Size of Rail gauge for installation (in mm): Longer axis

215 Size of Rail gauge for installation (in mm): Shorter axis

216 Wheel base

217 Particulars of the heaviest package for transport, in Kg.

218 Particulars of the heaviest package for transport : Dimentions (Length x Breadth x Height), in mm

219 Type and Make of Pressure relief device 220 No. of Pressure relief devices per transformer unit (Nos.)

221 Minimum pressure at which the Pressure device operates (kPa)

222 Details of turret mounted HV bushing current transformer for REF Protection. : Type and voltage class

223 Details of turret mounted HV bushing current transformer for REF Protection. : No. of cores (Nos.)

224 Details of turret mounted HV bushing current transformer for REF Protection. : Ratio

225 Details of turret mounted HV bushing current transformer for REF Protection. : Accuracy class

226 Details of turret mounted HV bushing current transformer for REF Protection. : Burden in (VA)

227 Details of turret mounted HV bushing current transformer for REF Protection. : Accuracy limit factor

228 Details of turret mounted HV bushing current transformer for REF Protection. :Knee point voltage (Volts)

229 Details of turret mounted HV bushing current transformer for REF Protection. :Maximum resistance of secondary winding (in ohms)

61

230 Details of turret mounted bushing current transformer in Neutral connection to earth for REF protection . : Type and voltage class

231 Details of turret mounted bushing current transformer in Neutral connection to earth for REF protection . : No. of cores (Nos.)

232 Details of turret mounted bushing current transformer in Neutral connection to earth for REF protection . : Ratio

233 Details of turret mounted bushing current transformer in Neutral connection to earth for REF protection . : Accuracy class

234 Details of turret mounted bushing current transformer in Neutral connection to earth for REF protection . : Burden (VA)

235 Details of turret mounted bushing current transformer in Neutral connection to earth for REF protection . : Accuracy limit factor

236 Details of turret mounted bushing current transformer in Neutral connection to earth for REF protection . :Knee point voltage (Volts)

237 Details of turret mounted bushing current transformer in Neutral connection to earth for REF protection . :Maximum resistance of secondary winding (in ohms)

238 Characterstics of Insulating oil to be used : Density in gms/ cu. cm at 29.5 Deg. C 239 Characterstics of Insulating oil to be used : Kinematic viscocity in cSt at 27 Deg. C

240 Characterstics of Insulating oil to be used : Interfacial Tension at 27 Deg. C in N/M 241 Characterstics of Insulating oil to be used : Flash point in Deg. C (Min.)

242 Characterstics of Insulating oil to be used : Pour Point in Deg. C (Max.)

243 Characterstics of Insulating oil to be used : Neutralisation Value: Total Acidity Max., in mg of KOH/gm

244 Characterstics of Insulating oil to be used : Neutralisation Value: Inorganic Acidity Alcalinity

245 Characterstics of Insulating oil to be used : Corrosive Sulphur

246 Characterstics of Insulating oil to be used : Electric strength (Break down voltage) Min., in kV

247 Characterstics of Insulating oil to be used : Dielectric dissipation factor (tan delta) at 90 Deg. C Max.

248 Characterstics of Insulating oil to be used : Water content, in ppm

249 Characterstics of Insulating oil to be used : Specific resistance at 90 Deg. C (Min.), in ohms-cm

250 Characterstics of Insulating oil to be used : Specific resistance at 27 Deg. C (min.), in ohms-cm

251 Characterstics of Insulating oil to be used : Oxidation stabality Neutralisation Value after oxidation , in mg KOH/gm

252 Characterstics of Insulating oil to be used : Oxidation stabality Total sludge value percentage by weight after oxidation

253

Ageing characterstics after accelerated aging (open breaker method with copper catalist) As per Appendix -C of IS-335-1983: Specific resistance at 27 Deg. C (Min.), in ohms-cm

254

Ageing characterstics after accelerated aging (open breaker method with copper catalist) As per Appendix -C of IS-335-1983: Specific resistance at 90 Deg. C (Min.), in ohms-cm

255 Ageing characterstics after accelerated aging (open breaker method with copper catalist) As per Appendix -C of IS-335-1983: Tan delta at 90 Deg. C (Max.)

256 Ageing characterstics after accelerated aging (open breaker method with copper catalist) As per Appendix -C of IS-335-1983: Total Acidity Max., in mg of KOH/gm

257 Ageing characterstics after accelerated aging (open breaker method with copper catalist) As per Appendix -C of IS-335-1983: Total sludge value percentage by weight

258 Characterstics of Insulating oil to be used : Presence of oxidation inhibitors

259 SCADA Compatibility (Provisions available)

260 Whether T/F is suitable for Bi-directional Flow of power as per Clause 5.1.1

261 Maximum axial length of the transformer from the center line of the transformer bay to the extreme edge of the transformer (including accessories) in metres. (as per

62

Clause 5.3)

262

Do you have proven experience of not less than 5 years in the design, Manufacturer, Supply and Testing at the works of equipment offered for equal or higher voltage class (Clause 10.1)

263 Whether transformers supplied by you are in successful operation for atleast two years as per Clause 10.1

264 Do you have adequate in-house testing facilities for conducting acceptance tests as per Clause 10.2

265 Do you have minimum turn-over of 15 crore in any one financial year during last three years as per Clause 10.3

266 Do you have any valid ongoing collaboration conforming to Clause 10.4 and submitted documentary evidence in support thereof.

267 Whether documentary evidence confirming requirement under Sr.No.72 to 75 above.

268 Is the transformer type tested as per Clause No.10.6

269 Whether the transformer offered is type tested within last five years

270 Are you ready to repeat type test which are conducted earlier than five years from the date of tender opening without any extra cost to MSETCL.

271 Whether valid undertaking in the form of Affidavit on Stamp Paper of Rs.100/- denomination as per Clause 5.6(a) is submitted

272 Details of OLTC as per Clause 5.11.1(a), 5.11.1(c) , 5.11.2 (a) & 5.11.2 (r)

273 Maximum no load loss (Iron loss) at rated voltage and at rated frequency at 75 Deg C in KW

274 Maximum load loss including copper loss because of consumption by the cooler fans, motor pump sets etc at rated current and at rated frequency at 75 Deg C in KW

275 Maximum auxiliary losses at rated MVA in KW

63

Annexure-B2

50 MVA, 132-110/33KV

Guaranteed Technical Parameters:

1 Name of the Manufacturer and country of origin

2 Conforming to standard

3 Service (Indoor/outdoor)

4 Ratings: With ONAN cooling-MVA

5 Ratings:With ONAF cooling-MVA

6 Rated no load voltage: HV, in KV

7 Rated no load voltage: LV, in KV

8 Temperature rise of top oil, in Deg. C

9

Temperature rise of winding measured by resistance : With ONAN cooling, in Deg. C

10

Temperature rise of winding measured by resistance : With ONAF cooling, in Deg. C

11 Rated frequecy (HZ)

12 No. of windings

13 Number of phases

14 Connection symbol & vector group

15 Tappings:-Type of tap changer

16 Tappings:-Tap step (percent)

17 Tappings:-Total tap range (+) percent to (-) percent

18 Tappings:-Tappings provided at

19 Magnetisation data at no load : Current in Amps

20 Magnetisation data at no load : Power factor

21

Magnetisation data at no load : Max. Loss in kW(core loss + dielectric loss)

22

Magnetisation data at no load : Max. flux density in lines/ sq. cm .at 100% rated no load voltage

23

Magnetisation data at no load : Max. flux density in lines/sq. cm. at 110% rated no load voltage.

24

Magnetisation data at no load : Max. flux density in lines/sq. cm at maximum rated primary voltage (i.e. 105% rated no load voltage)

25

25) Load loss at rated current at 75 Deg. C : For ONAN Rating, Cu loss, in KW

26

Max. Load loss including cooler loss at rated current at 75 Deg. C : For ONAF Rating, Cu loss + Cooler loss, in KW

64

27

Impedance at rated current and frequency at 75 Deg. C on rated MVA: At normal tap, in % (HV to LV)

28

Impedance at rated current and frequency at 75 Deg. C on rated MVA: At Max. voltage tap, in % (HV to LV)

29

Impedance at rated current and frequency at 75 Deg. C on rated MVA: At Min-voltage tap, in % (HV to LV)

30

Reactance at rated current and frequency and normal tap on rated MVA base :- HV to LV - in %

31 Resistance at 75 Deg. C of : HV Winding (in ohms)

32 Resistance at 75 Deg. C of : LV Winding (in ohms)

33

Efficiency at 75 Deg. C, taking into account input to cooling plant as loss : At 125% full load and unity p.f. - in %

34

Efficiency at 75 Deg. C, taking into account input to cooling plant as loss : At 100% full load and unity p.f - in %

35

Efficiency at 75 Deg. C, taking into account input to cooling plant as loss : At 75% full load and unity p.f - in %

36

Efficiency at 75 Deg. C, taking into account input to cooling plant as loss : At 50% full load and unity p.f. - in %

37

Efficiency at 75 Deg. C, taking into account input to cooling plant as loss : At 125% full load and 0.8 p.f. - in %

38

Efficiency at 75 Deg. C, taking into account input to cooling plant as loss : At 100% full load and 0.8 p.f. - in %

39

Efficiency at 75 Deg. C taking into account input to cooling plant as loss : At 75% full load and 0.8 p.f. - in %

40

Efficiency at 75 Deg. C taking into account input to cooling plant as loss : At 50% full load and 0.8 p.f. - in %

41

Maximum efficiency and load at which it occurs : At 125% full load (percent at percentage full load and p.f.) - in %

42

Maximum efficiency and load at which it occurs : At 100% full load (percent at percentage full load and p.f.) - in %

43

Maximum efficiency and load at which it occurs : At 75% full load (percent at percentage full load and p.f.) - in %

44

Maximum efficiency and load at which it occurs : At 50% full load (percent at percentage full load and p.f.) - in %

45

Regulation at full load & at 75 Deg. C : At Unity p.f.(lag), in %

46

46) Regulation at full load & at 75 Deg. C: At 0.8 p.f.(lag), in %

47

Overload capacity for 2 hours after continuous full load run (Please mention temperature & MVA capacity as per IS 6600)

48 Test Voltages : Lightning impulse withstand, kV (Peak) (HV)

49

Test Voltages : Power frequency voltage withstand, kV(rms) (HV)

50 Test Voltages : Switching surge withstand, kV (peak) (HV)

51 Test Voltages : Lightning impulse withstand, kV (Peak) (LV)

52 Test Voltages : Power frequency voltage withstand, kV(rms) (LV)

53 53) Test Voltages : Switching surge withstand, kV (peak) (LV)

65

54

Noise level when energized at normal voltage and normal frequency at no load, in db.

55 Approximate weight : Core (in Kg)

56 Approximate weight : Windings (in Kg)

57 Approximate weight : Tank & Fittings (in Kg)

58 Approximate weight : Oil (in Kg)

59 Approximate weight : Total weight (in Kg)

60 Approximate required quantity of oil, in Litres

61 Terminal connectors type and drawing no : HV

62 Terminal connectors type and drawing no : LV

63 Net core area in sq. metre

64 Type of transformer (Shell/Core)

65 Material of Laminations

66

Maximum flux density at rated voltage and frequency in lines/sq. cm

67 Type of joints between core limb and yoke

68 Conductor area in sq. cm and current density in Amp/sq. cm : HV

69 Conductor area in sq. cm and current density in Amp/sq. cm : LV

70 Type of Windings: HV

71 Type of Windings: LV

72 Winding insulation : HV : Type and Class/ Graded or Ungraded

73

Winding insulation : LV : Type and Class/ Graded or Ungraded

74 Insulating material : Turn Insulation : HV side

75 Insulating material :Turn Insulation : LV side

76 Insulating material : Between HV and LV

77 Insulating material : Between core & LV side

78 Insulating material : For core bolts, washers and end plates

79 Insulating material : Tapping connection

80 Type of axial support : HV winding

81 Type of axial support : LV winding

82 Type of Radial Coil Support :-HV winding

83 Type of Radial Coil Support :-LV winding

84 Clearance out of oil between HV windings (Ph. to Ph.) (in mm)

85 Clearance out of oil between LV windings (Ph. to Ph.) (in mm)

86 Clearance out of oil between Ph. To Ground, HV windings (in mm)

87 Clearance out of oil between Ph. To Ground, LV windings (in mm)

66

88 Details of Tank: Material for main tank

89 Details of Tank: Type of the tank

90 Details of Tank: Thickness of sides (in mm)

91 Details of Tank: Thickness of Bottom (in mm)

92 Details of Tank: Thickness of Cover (in mm)

93 Details of Tank: Thickness of Radiators (in mm)

94

Minimum clear height for lifting bell and for lifting core and windings from tank (in mm) (Untanking height)

95 Details of HV Bushings: Type

96

Details of HV Bushings:.One minute dry power frequency withstand voltage, kV (rms)

97

Details of HV Bushings: 1.2/50 ms. lightning impulse withstand voltage, kV (peak)

98

Details of HV Bushings: Switching surge withstand voltage, kV(peak)

99 Details of HV Bushings: Creepage distance, in Air (mm)

100

Details of HV Bushings: Weight of assembled bushings (kg)

101

Details of HV Bushings: Phase to earth clearance in Air of live parts at the top of bushings,in mm

102

Details of HV Bushings: Maximum current rating of the bushings, in Amps.

103 Details of HV Bushings: Grade of oil in the bushings

104

Details of HV Bushings: Quantity of oil in the bushings, in Litres

105 Details of HVN Bushings: Type

106

Details of HVN Bushings:.One minute dry power frequency withstand voltage, kV (rms)

107

Details of HVN Bushings: 1.2/50 ms. lightning impulse withstand voltage, kV (peak)

108

Details of HVN Bushings: Switching surge withstand voltage, kV(peak)

109

Details of HVN Bushings: Creepage distance in Air (in mm)

110

Details of HVN Bushings: Weight of assembled bushings (in kg)

111

Details of HVN Bushings: HV Neutral Terminal to earth clearance in Air in mm

112

Details of HVN Bushings: Maximum current rating of the bushings, in Amps.

113 Details of HVN Bushings: Grade of oil in the bushings

114

Details of HVN Bushings: Quantity of oil in the bushings (Litres)

115 Details of LV Bushings: Type

116

Details of LV Bushings:.One minute dry power frequency withstand voltage, kV (rms)

67

117

Details of LV Bushings: 1.2/50 ms. lightning impulse withstand voltage, kV (peak)

118 Details of LV Bushings: Switching surge withstand voltage, kV(peak)

119 Details of LV Bushings: Creepage distance, in Air (mm)

120 Details of LV Bushings: Weight of assembled bushings (kg)

121

Details of LV Bushings: Phase to earth clearance in Air of live parts at the top of bushings, in mm

122

Details of LV Bushings: Maximum current rating of the bushings, in Amps.

123 Details of LV Neutral Bushings: Type

124

Details of LV Neutral Bushings:.One minute dry power frequency withstand voltage, kV (rms)

125 Details of LV Bushings: Creepage distance, in Air (mm)

126

Details of LV Bushings: Weight of assembled bushings (kg)

127

Details of LV Bushings: Phase to earth clearance in Air of live parts at the top of bushings, in mm

128 Details of LV Bushings: Maximum current rating of the bushings, in Amps.

129 Details of LV Neutral Bushings: Type

130

Details of LV Neutral Bushings:.One minute dry power frequency withstand voltage, kV (rms)

131 On Load Tap Changing gear : Make and Type

132 On Load Tap Changing gear : Rating: Rated voltage, in kV

133 On Load Tap Changing gear : Rating: Rated current Amps

134 On Load Tap Changing gear : Rating: Step voltage kV

135 On Load Tap Changing gear : Rating: No.of steps Nos.

136

On Load Tap Changing gear : Approximate over all dimensions (Width x Breadth x Depth) in mm

137 On Load Tap Changing gear : Approximate over all weight in kgs.

138 On Load Tap Changing gear : Approximate over all quantity of oil in litres

139 On Load Tap Changing gear : Time to complete one tap- change step, in seconds

140 Cooling System: Grade of Oil

141 Cooling System: Quantity of oil in Transformer (litres) 142 Cooling System: Weight of oil in Transformer( Kg)

143 Cooling System: Total radiating surface, in sq. metre

144 Cooling System: Total number of Radiators/ Banks for transformer and dimensions of tubes

145 Cooling System: Total weight of Radiators (kg) 146 Cooling Equipment : Fan Motor: Make and Type (Details) 147 Cooling Equipment : Fan Motor: Number connected

148 Cooling Equipment : Fan Motor: Nos. in standby

149 Cooling Equipment : Fan Motor: Rated Power, in KW 150 Cooling Equipment : Fan Motor: Rated voltage (Volts)

151 Type and size of oil temperature indicator and whether supervisory alarm contacts provided

152 Type of oil level indicator and whether supervisory alarm contact for low oil level provided

153

Type and size of Gas operated relay and whether supervisory alarm and trip contacts provided and their ratings and Nos.

68

154 No. of Breathers provided (No.) 155 Type of dehydrating agent used for breathers

156 Capacity of conservator vessel (Litres)

157 Drain valve size required/ fitted : in mm

158 Drain valves required/ fitted, in Nos.

159 Filter Valve size required/ fitted : in mm

160 Filter Valves required/ fitted : in Nos

161 Sampling valve size required/ fitted : in mm

162 Sampling valves required/ fitted : in Nos

163 Size of Rail gauge for installation (in mm): Longer axis

164 Size of Rail gauge for installation (in mm): Shorter axis

165 Wheel base

166 Particulars of the heaviest package for transport, in Kg.

167 Particulars of the heaviest package for transport : Dimentions (Length x Breadth x Height), in mm

168 Type and Make of Pressure relief device 169 No. of Pressure relief devices per transformer unit (Nos.)

170 Minimum pressure at which the Pressure device operates (kPa)

171

Details of turret mounted HV/HV neutral bushing current transformers for REF Protection. : Type

172

Details of turret mounted HV/HV neutral bushing current transformers for REF Protection. : No. of cores (Nos.)

173

Details of turret mounted HV/HV neutral bushing current transformers for REF Protection. : Ratio

174

Details of turret mounted HV/HV neutral bushing current transformers for REF Protection.: class

175

Details of turret mounted HV/HV neutral bushing current transformers for REF Protection. :Knee point voltage (Volts)

176

Details of turret mounted HV/HV neutral bushing current transformers for REF Protection. :Maximum resistance of secondary winding (in ohms)

177 Insulating oil to be used (IS Standard) 178 SCADA Compatibility (Provisions available) 179 Whether T/F is suitable for Bi-directional Flow of power

180

Maximum axial length of the transformer from the center line of the transformer bay to the extreme edge of the transformer (including accessories) in metres. (as per Clause 5.3)

181 Whether the transformer offered is type tested within last five years

182 Are you ready to repeat type test which are conducted earlier than five years from the date of tender opening without any extra cost to MSETCL.

183 Maximum no load loss (Iron loss) at rated voltage and at rated frequency at 75 DC in KW

184 Maximum load loss including copper loss because of consumption by the cooler fans, motor pump sets etc at rated current and at rated frequency at 75 DC in KW

185 Maximum auxiliary losses at rated MVA in KW

69

Annexure B1

Bill of Material

S.No. Particulars Make Type Quantity 1 Conservator for main tank, with oil filling hole and cap, isolating

valves, drain valve, magnetic oil level gauge with low oil level alarm contacts and dehydrating breather: Buchholz relay, double float type, with isolating valves on both sides, bleeding pipe with petcock at the end to collect gases and alarm and trip contacts

2 Conservator for OLTC with drain valve, Buchholz (Oil Surge) relay, filling hole with prismatic oil level gauge and dehydrating breather.

3 Oil preservation equipment. 4 Pressure relief device with alarm contacts. 5 Air release plug. 6 Inspection openings and covers 7 Bushing with metal parts and gaskets to suit the termination

arrangement. 8 Oil temperature indicators. 9 Covers lifting eyes, transformer lifting lugs, jacking pads, towing

holes and core and winding lifting lugs. 10

Protected type mercury (or alcohol) in glass thermometer. 11 Bottom and top filter valves with threaded male adaptors, bottom

sampling valve and drain valve. 12 Rating and diagram plates on transformers and auxiliary

apparatus 13 Earthing terminals. 14 Flanged bi-directional wheels. 15 Cooler Control Cabinet. 16

On load tap changing equipment and OLTC control cabinet. 17 Cooling equipment. 18 Drain valves/plugs shall be provided in order that each section of

pipe work can be drained independently. 19 Bushing CTs. 20 Insulating oil.

21 Terminal marking plate. 22 Jacking pads. 23 Lifting bollards. 24 Haulage lugs. 25 Cover Lifting lugs. 26 Valve schedule plate. 27 Microprocessor based numerical RTCC Panel. 28 Temperature Indicator compatible with SCADA 29 Fibre optic based temperature measuring system complete 30 Transformer monitoring cum tap changer controller

70

Annexure B2

List Of Mandatory Spares

1) 220 kV Bushings : 39

2) 132 kV L.V Bushings : 39

3) 24 kV neutral Bushings : 39

4) Bushing CTs : 39