Answer / pillay

The sample oil to be tested for dielectric test is collected
and put into the tester and the average of 6 tests is
taken.The minimum withold voltage is as per local regulations.
causes of low dielectric results are usually exposure of the
insulating oil to moisture through the breather or there is an
exposed opening, poor quality oil being used. high acidic
content.The insulating oil should be replaced or dehydrated.
breathers silica gels should be maintained good all the time
and check for any leaks or any exposure to atmosphere must be
rectified.

Answer / ravikumar.g

The transformer Oil testing to be done in filtration unit
by checking the Oil Testing Kit in KV

20 KV low

when the voltage are not balancing properly and the taps
are changing regurly the oil becomes carbonsied this
carbonsied oil is acts as conductor.

So these problem so we change the Oil.

The salution for this changing the oil the transformer has
to be oilfilteration in once in a year.

Answer / saroj

TRF oil is tested in a glass pot where high voltage,KV is
applied between two electrodes and sparking at electrode to
be observed. For good oil , it comes about 40~60KV/mm .If
it comes lower then filteration is required. Those TRF
having tap changing is frequently required it is
recommended to do filteration in once in year.Also its
value goes low because of moisture ingress in oil .

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