Electrical Test Question for larger transformers

[Rodmcm]

A question has been raised on whether there is a need to check for deterioration of winding insulation after impulse tests, possible through partial discharge testing?
Transformer size 132kV/11kV 52MVA

Comments?

 

[PDAGuru]

I would say no. The impulse test itself is already a test for deterioration of winding insulation. It does contribute somewhat to aging but applying another surge, even a large one like that endured in an impulse test, should not significantly deteriorate the insulation.

 

[ciobanj]

The distructive test performed on transformers of any size has either pass or fail result.
Once the result of a specific test has been estabilished as "passed" there is not a need to investigate any further.

 

[prc]

Correct sequence of testing is impulse test followed by induced overvoltage test with or without PD.Any hidden defect during impulse test will come out in AC test.PD test is usually insisted for voltgae class 220 kV and above.

 

[Rodmcm]

Thanks