I have connected 04nos. earthings to a transformer through
04nos. earthing pits seperately. 02nos. earthings are
connected to T/F body, and 02nos. earthings are connected to
T/F neutral.T/F capacity is 2000KVA, 11KV/415V. But after
completing of 02 years successful operation ,we are
facing following problems-

1. CT/PT occured blast one time
2. HT cable box occured blast two times
3. One body earthing strip and one neutral earthing strip of
transformer are overlapping at some places. Whenever these
two strips are pressed at overlapped points, they made spark.

What is the reason of spark?

Please explain the reason & rectification of above problems

Answer Posted / k.bhaskar

I think your neutral earth pits resistance is not
good,ensure each earth pit resistance with out grid.The
reason for sparking may be body earth is good and some
potential is there in the neutral path.

Second ensure transformer core channel to earth connection
(inside).Measure the winding resistance and unbalance load
distribution may also cause developing voltage in Neutral.

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