At the time of 1st charging of transformer, there were huge inrush curre

At the time of 1st
charging of
transformer, there
were huge inrush
current, so why at
that diffrential relay
are not operated? Why?

Question Posted / hardipengg12

3 Answers
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At the time of 1st charging of transformer, there were huge inrush current, so why at that..

Answer / m.s prabhu

THE TIME DURATION OF THE INRUSH CURRENT IS LESS SO THE CTs
WILL SATURATE, TIME DURATION OF THE INRUSH CURRENT IS LESS
THEN THE PICKUP DELAY OF THE DIFFRENTIAL RELAY.

Is This Answer Correct ?

13 Yes

1 No

At the time of 1st charging of transformer, there were huge inrush current, so why at that..

Answer / vinod

During the first charging of transformer the magnetising
inrush current is second harmonic, differential relay is
provided with second harmonic trip by pass with sufficient
time. Also 87 relay having 5 th harmoninic by pass during
lightning surges.

Is This Answer Correct ?

5 Yes

1 No

At the time of 1st charging of transformer, there were huge inrush current, so why at that..

Answer / k.prakashchandra

The currents in both primary and secondary for the same
phase are balanced.

Is This Answer Correct ?

2 Yes

10 No

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