why middle phase should used for earth fault and other
phases used for over current in overcurrent and earth fault
relay?

Answers were Sorted based on User's Feedback



why middle phase should used for earth fault and other phases used for over current in overcurrent..

Answer / prasun bhaumik

It is a convention there will not be any problem
technically if we change that arrangement

Is This Answer Correct ?    7 Yes 4 No

why middle phase should used for earth fault and other phases used for over current in overcurrent..

Answer / vishal ingle

Not necessary to use only the middle phase.
our Back up protection cosist of two overcurrent elements
and one earth fault element.
under normal condition vector (IR + IY + IB) = 0
in fact middle phase is not used for earth fault prot.
Earth fault relay is connected between the star point of
all three phases (after O/C Relay) and the earth. if any
unbalance occurs, the unbalance current will flow through
the e/f relay.

Is This Answer Correct ?    1 Yes 1 No

why middle phase should used for earth fault and other phases used for over current in overcurrent..

Answer / gunasekaran

on that point resiudual current is zero normally current sum
is zero at thatt point whenever balance is distrubed current
will flow

Is This Answer Correct ?    2 Yes 3 No

why middle phase should used for earth fault and other phases used for over current in overcurrent..

Answer / j.dev singh

for balancing of two phases current in relay.

Is This Answer Correct ?    0 Yes 1 No

why middle phase should used for earth fault and other phases used for over current in overcurrent..

Answer / amrander singh

Please tell the answer Clearly......waiting..

Is This Answer Correct ?    0 Yes 4 No

why middle phase should used for earth fault and other phases used for over current in overcurrent..

Answer / pragnesh patel

This kind of arrangement is use for saving one over current
relay.

Is This Answer Correct ?    0 Yes 4 No

why middle phase should used for earth fault and other phases used for over current in overcurrent..

Answer / vinuram

first and 3rd phases are having voltage and current
flactuation.

Is This Answer Correct ?    0 Yes 7 No

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