Answer / jk

Dear MMK. What's wrong UR posting. Ammeter reading from
left to right(0 to 90DEgree). It's starting point is
leftside only. then how it possible.

I think, for messuring CT it may work. but in
cause of protection CT, defenitly it will cause for
tripping the relay & system

Answer / k.prakashchandra

Only the meters which require voltage input also show the
negative readings.Directional and distance relays(on reverse
zone) trip.

Answer / sanjay sharma

It is depend on type of scheme, in protection , if three phase ckt then reversal of 1 CT polarity relay will (if set value Reach), reversal of all three phases will not effect for normal protection (except to directional protection). In case of metering Ameter will not effect, but energy meter will not work,if single CT reverse in case of three phase, mode (import/export) will change.

Answer / mkk

sorry jk i mean torque produced in the reverse direction
i.e. needle is in left position and it still tries to move
to left position.

Answer / chadu

CT refferce to current transformer to sence the current.
if u reverse the ct treminals ur the same current reading
but with opposite polararity.

Answer / badusha

for metering CT, it will not read the actual readings.
but in the case of protection CT, surely it will trip the relay.

Answer / aggarwala111

Ammeter show the opposite reading as previous.

Answer / grg

If we reverse the polarity the relay will see reverse
direction.The protected zone will get reversed.(incase of
distance protection)

Answer / sanj

CT polarity is vital part. if polarity changes of any ct out of 3 impact will be there both for measuring and protection ckt.
For measuring ckt please watch
https://www.youtube.com/watch?v=FqLVEeoaXws&t=181s

and for protection ckt impact watch
https://www.youtube.com/watch?v=p-cuvTe8sX8&t=129s

Answer / sunil pund

Ammeter showing the reverse direction

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