(6) 6.6 kv 415 v transformer

JSW Energy Limited STANDARD CHECKLIST: SYSTEM COMMISSIONING SHEET 1 OF 9

STATION: UNIT: _____

Date:

PLANT ITEM: 6.6 KV / 415 V TRANSFORMER Ref.No.:

Name of the system: ___________________ Plant area: ________________________

System Drawing No: __________________ Manufacturer’s Name:__________________

Location :_____________________ Serial No: ________________________

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1. GENERAL INSPECTION AND CHECKS

1.1 Check that the transformer and oil its accessories are erected completely and the pre-ELECTRICAL inspection & testing certificates are available.

1.2 Check that the transformer has adequate ventilation and free access from all sides.

1.3 If the transformer is situated indoors, see that transformer room is well ventilated.

1.4 Check that transformer, bushings, insulators, cables, tap changer are free from any damage.

1.5 Check that all foundation bolts and other fixing arrangements/ of equipments are properly tightened.

1.6 Check that stops are provided where the transformer is mounted on rollers.

1.7 Check that the marking of terminals are correct.

1.8 Check that the tightness of all cable and wiring connection.

1.9 Check the colour code of the cables for correctness.

1.10 Check that all cable and wiring connections are done as per wiring drawings.

1.11 Check that name plate are clear and are properly fixed.

JSW Energy Limited

STANDARD CHECKLIST: SYSTEM COMMISSIONING SHEET 2 OF 9


Date:


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1.12 Labeling & identifications of different parts are correct and satisfactory.

1.13 Fire fighting system is adequate and satisfactory.

1.14 Surrounding areas are clean and safe for commissioning operation and maintenance.

1.15 Check the clean lines of all contact surfaces, insulator surfaces.

1.16 Check the explosion vent and its diaphragms if any.

1.17 Check the breather system and its desiccant’s conditions.

1.18 Check that bushing arcing horns (if provided) are fixed properly and their gap adjusted as per drawing.

1.19 Check all protective covers and shields are fixed properly.

1.20 Release any air trapped in the buchholz relay, Mercury switches of buchholz relays if clamped for transportation should be put into service condition check for correct mounting.

1.21 Check all indicating and controlling instruments are properly placed in their respective positions.

1.22 Check the transformer oil tank levels.

1.23 Check that all drain line valves and plugs are properly tightened and there is no oil leak.

1.24 Check that all vent plugs are properly tightened after releasing trapped air.

1.25 Check that all the earthing points of the transformer are solidly grounded.

JSW Energy Limited



Date:

PLANT ITEM: 6.6 KV / 415 V TRANSFORMER Ref.No.

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1.26 Check the operation of the tap changer lever satisfactory.

1.27 Ensure that the transformer and its components are properly painted.

1.28 HV, LV, and Neutral bushings are to be checked for cleanliness, proper take off connections and clearances. The take off connections should not impose any undue strain on the terminals.

1.29 Ensure that cable glands are properly earthed.

1.30 Ensure proper earthing of HV Neutral to Earth and LV Neutral to Earth either directly or through resistances with earth strips properly supported and held away from main tank and radiators.

1.31 Ensure station earth resistance is less than 0.5 ohm, by testing with an earth megger.

JSW Energy Limited



Date:


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2.0 TESTS AND TESTING PROCEDURES:

2.1 IR TESTS:

With a 1000 V or 2.5 Megger measure the following insulation resistances.

IR Value with : _________________ V . Megger.Ambient temp. : _________________ deg C

BETWEEN HV TO E :

i. ___________________ Mega-ohms.ii. ___________________ Mega-ohms.iii. ___________________ Mega-ohms.

BETWEEN LV TO E :


BETWEEN HV TO LV :


After the above tests put back all connection properly.

2.2 Check for proper insulation resistance of all control and Protective wirings after removal of earth link and fuses which are to be put back after tests.

JSW Energy Limited



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2.3 Check the continuity of windings

HV ___________________ LV ____________________

2.4 VOLTAGE RATION RESTS:

With a LT 3 phase supply applied on the HV side, measure the corresponding LV side voltages on all taps and on all phases by operating the tap switch. (the values should be similar for all the phases)

2.5 Magnetizing current test with LT voltage applied to the HV side, measure the magnetizing current on all taps and on all phases. These values should be in the order of a few mill-amps.

2.6 Vector group tests.

Carry out vector group tests of the transformer by applying 3 phase, 415 V to the HV terminals with normal earth connections to the star point removed.

Connect one HV terminal to one LV terminal.

With transformer on nominal taps measure the following voltages.

JSW Energy Limited



Date:


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2.6TABLE

HV TO LV =

Bet- Volts Bet- Volts Bet- Volts Bet- Volts Bet- Voltsween ween ween ween ween

A-B A-a A-b A-c a-bB-C B-a B-b B-c b-cC-A C-a C-b C-c c-a

Where A, B, & C = HV Terminals. a, b, & c = LV Terminals.

Draw the vector diagrams from the results so obtained during the tests and compare the same with that given or the manufacturer.

All connections are to be normalized after the tests.

2.7 Samples of oil will be taken and sent to the chemical laboratory to be tested.

2.8 Winding temperature CT is to be tested for ratio, magnetizing and polarity checks.

2.9 All the alarm contacts when closed should initiate the visual and audio indications.

2.10 The trip contacts when closed should trip the trip relay and given the visual indication and alarm,

JSW Energy Limited



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2.11 BUCHHOLZ DEVICE TESTS :

i. Inclination (degrees)

Longitudinal (3 deg – 7 deg ) _____________________ Lateral (0 deg – 5 deg ) _____________________

ii. Quantity of air to operate the alarm contacts.

C.C.S. make __________________ C.C.S. Breaks __________________

iii. Surge contacts : Approximate minimum air pressure required to operate the surge contacts __________________ .

iv. Make the gas contacts to operate alarm relay.

v. Make the trip contacts to operate flag relay and trip relay simultaneously.

vi. Release all air from Buchholz Relay.

2.12 W T I TESTS :

- Heater coil circuits :

Coil resistance = ______________________ Ohms.Shunt resistance Across heater = _____________________ Ohms.

JSW Energy Limited



Date:


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2.12 - Heater coil tests:

Current injected (F.L.C.) _______________ amps. Initial temperature _______________ deg C. Top oil temperature _______________ deg C. Temperature increment ________________ deg C. / mins. Steady state temperature _________________ deg C.

- Calibration test on WTI indicator :

Test Temperature WTI

25 deg C 30 deg C 40 deg C 50 deg C 60 deg C 70 deg C 80 deg C 90 deg C 100 deg C

- Check alarm contact by operating alarm relay.

- Check trip contacts by operating flag relay and trip relay.

A. - Alarm contact settings ________________ .B. - Trip contact settings ________________ .

JSW Energy Limited



Date:

PLANT ITEM: 6.6 KV / 415 V TRANSFORMERRef.No.:

SN ACTIVITYSTATUS

2.13 OFF LOAD TAP CHANGER TESTS :

Tap changer counter reading :

Initial _________________ Final _________________

Raise and lower the handle locally in full range manually and see the circuit continuity at each tap position and check also the handle interlock.

REMARKS :

Name Signature Date

Contractor - Erection

Contractor - Commg.

JSWEL - Erection

JSWEL - Commg.

(6) 6.6 kv 415 v transformer

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