Power transformer insulation test
Power transformer insulation test
(OP)
We have old power transformer working since 1976. It is 33/11 kV, we change its oil, and treat all leaking in its body, but when we test its insulation using 5 kV Megger its insulation value was just 80 M ohm, but the temperature was 50 degree centigrade.
According to the tables this value is acceptable because its temperature is very high and its very old, but we are hesitated to energize it with the power because of this low value (80 M ohm), so could any one help?
Thanks in advanced
Kind regards,
Safy
According to the tables this value is acceptable because its temperature is very high and its very old, but we are hesitated to energize it with the power because of this low value (80 M ohm), so could any one help?
Thanks in advanced
Kind regards,
Safy






RE: Power transformer insulation test
RE: Power transformer insulation test
According to the attached file in the link below at the last page this value is acceptable, but we are just worried!
Actually we didnt change all the oil at one time but we change it in steps to avoid the leakage of the humidity to the coils, the oil has been filtered and tested and its breakdown value was 70 KV at 2.5 cm gap.
Safy
RE: Power transformer insulation test
RE: Power transformer insulation test
RE: Power transformer insulation test
Thanks a lot for your point of view but could you tell me please exactly what is the minimum acceptable water content in PPM in such case
Regards
RE: Power transformer insulation test
RE: Power transformer insulation test
your informations are valuable