46428300 Testing of Power Transformer

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TESTING OF POWER TRANSFORMERS

KT 80 GB 2000-01 ABB Oy Power transformer

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TESTING POWER TRANSFORMERS Test procedures and equipment used for the testing of large power transformers at ABB Oy, Power transformer, Vaasa Works are dealt with in the following sections. The measuring equipment differens from those explained herein. The priciples of routine, type and special tests are however similar and thus this booklet is applicable for testing of distribution transformers too. The electrical characteristics and dielectric strenght of the transformers are checked by means of measurements and tests defined by standards. The tests are carried out in accordance with IEC Standard 76, Power Transformers, unless otherwise specified in the contract documents.

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Contents 1.

Summary of dielectric tests

Pages 4

Routine tests 2.

Measurement of voltage ratio and check of connection symbol

5...6

3.

Measurement of winding resistance

7…8

4.

Measurement of impedance voltage and load loss

8…11

5.

Measurement of no-load loss and current

12…13

6.

Induced AC voltage test (ACSD)

14…15

7.

Separete-source voltage withstand test

16

8.

Operation tests on on-load tap-changer

17

9.

Lighting impulse test

18...24

10.

Partial discharge measurement

25...30

Type tests and special tests 11.

Measurement of zero-sequence impedance

31

12..

Capacitance measurement

32...33

13.

Insulation resistance measurement

34

14.

Loss factor measurement

35…36

15.

Measurement of the electric strengh of the insulating oil

37

16.

Temperature-rise test

38…41

17.

Test with lightning impulse, chopped on the tail

42…43

18.

Switching impulse test

44…46

19.

Measurement of acoustic sound level

47…48

List of equipment

49...55

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1. SUMMARY OF DIELECTRIC TESTS According to the Standard IEC 76-3 the dielectric test requirements for a transformer winding depend on the highest voltage for equipment Um applicaple to the winding and on whether the winding insulation is uniform or non-uniform.

Lightning impulse (LI) (see

Switching impulse (SI) (see

Long duration AC (ACLD)

Short duration AC (ACSD)

Separate source AC

clause 13 and 14)

clause 15)

Um ≤ 72,5

Type (note 1)

Not applicable

Not applicable (note 1)

Routine

Routine

72,5