there is a power transformer 66/11kV in delta-delta connection has 5 feeder com

there is a power transformer 66/11kV in delta-delta
connection has 5 feeder coming out from the secondary side.
One of the feeder in it normally loaded (loaded than other
feeder)and this feeder usually trips with double OCR causing
the bank transformer to trip. Now if the load of this feeder
is put on other transformer then that no problems occurs on
that transformer or the load. However normally all the
test(IR, PI, short ckt, open ckt,grounding test and other )
has been conducted for this but evertything transformer.....
I am not geting what is the actual problem...

Question Posted / ajit152007

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there is a power transformer 66/11kV in delta-delta connection has 5 feeder coming out from the sec..

Answer / parin patel

This thing happened dew to %Z of transformer.lesser the %Z current supplied by transformer will be more.
example:- there are two transformer
transformer 1: 66/11 kv,%Z= 5% ,15 kVA
transformer 2: 66/11 kv,%Z= 7%, 15kVA
If load is constant(same), current supplied by transformer 1 at 11 kv is more than current supplied by transformer 2 at 11 kv.

In your case ,you have to check the value of feeder current when it's supplied by two different transformer.in both case it might be different.

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there is a power transformer 66/11kV in delta-delta connection has 5 feeder coming out from the sec..

Answer / k.prakashchandra

More data is required for analysis.If the transformers are
of same capacity and relays are identical ,interchange the
relays of transformer banks and watch.

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