Partial discharge test for oil cooled transformers
Partial discharge test for oil cooled transformers
(OP)
Anyone pl. discuss :Is it possible to carry Partial Discharge test for oil cooled transformers (400kV/16,5kV)? And also pl. inform if any standard available for the above test for oil cooled transformer.
Thanks a lot.
Thanks a lot.






RE: Partial discharge test for oil cooled transformers
RE: Partial discharge test for oil cooled transformers
RE: Partial discharge test for oil cooled transformers
Gunnar Englund
www.gke.org
RE: Partial discharge test for oil cooled transformers
Thanks..
RE: Partial discharge test for oil cooled transformers
Gunnar Englund
www.gke.org
RE: Partial discharge test for oil cooled transformers
http:/
Sorry for the short link...
RE: Partial discharge test for oil cooled transformers
The list of papers is as short as the link ;)
A star for you.
* If money can buy happiness, who is selling it ? *
RE: Partial discharge test for oil cooled transformers
A wise transformer guy once told me to check for high water if you see the partial discharge pattern. It can turn normally satisfactory clearances into unsatisfactory clearances which allow partial discharge.
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RE: Partial discharge test for oil cooled transformers
RE: Partial discharge test for oil cooled transformers
RE: Partial discharge test for oil cooled transformers
When testing dry type transformers, the partial discharge start voltage is very repeatable.
When testing oil cooled transformers, if the test voltage is held for any length of time (partial discharge for seconds or less) the corona start voltage decreases drastically. What happens is the partial discharge breaks the oil (but not the solid insulation) into a gas and the gas breaks down at a much lower voltage than the oil. The partial discharge start voltage increases to it's original value if the transformer is not energized for some time. The time required for the transformer to return to it's original partial discharge start voltage depends on how long it takes for the gas to disolve into the oil, which depends on the insulation scheme. This time can be minutes or days.
An interesting question is, if you have a cast type transformer with an inclosed gas pocket, will the partial discharge increase the gas pressure, so that the longer there is partial discharge, the higher the partial discharge start voltage?
(I don't know the answer)