Answer / afrooz

Differential relay is a current sensing zone protection
relay.It is used to protect alternators,transformers from
internal short ckt,internal earth faults.

Answer / sudheer

DIFFERENTIAL RELAY is used to sense generator supply in two
different locations. in generator out put leads are six. in
three phase winding- three leads of begining of coils and
three leads of ends of coils.three leads are named R,Y,B
and other three leads are R1,Y1,B1. we make star connetion
by joint R1,Y1,B1 and make neutral point by this
junction.we ground this neutral.we provide three CT'S in
RYB side and three CT'S in R1 Y1 B1 side.
if any fault occurs in winding between RYB and R1 Y1 B1 the
resultant supply operates the differential relay and the
generator stops automatically.

Answer / gova

Diff relay compares the input current and output
current that flows through the equipment and if there is
any difference between them,then the relay will sense the
difference of two currents (called differential current)
and trip the equipment protected if the differential
current exceeds the setting.

diff relay used in transformer,Generator,lines,motors etc.

what is MDB.pl abbreviate it.

regards
gova

Answer / gova

Diff relay will trip not only for earth fault but for phase
fault occurring inside the transformer.

Diff relay should not operate for through faults or
external faults-(out zone fault,i.e beyond protected zone)

regards
gova

Answer / pinaky

the above guy is 100 percent rite.
i can prove the matter how to calculate for differential relays
but am not a member rite now if u guys think that i can
share my knowledge with u please ask me to join Ur world.
regards
pinaky

by the way its called differential protection relay
make
seamens
abb
and few reputed companies with their proper logic settings.
Its a tough job to calculate the ct ratios for ct of ht and
lt protections.
ok enough for now
please remember me and i shall be ur friend for ever.

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