Can I use measuring current transformers in protection
purposes?

Answer Posted / ramesh kumar k

Mr.Mohit & Ms. Minnu...

both of u be cool specially... it is not a war field
yaar... ha.. ha...

What ms.minnu said is correct...

u cant use the measuring CT for protection purpose...and
protection ct also can't be used for measuring purpose...
it is not safe...

So Mr. Mohit, from my point of view what you have might
done is.. u have used a CT which u have purchased for
measuring purpose, but still having a additional core for
protection and u might have shorted the metering core
terminals and used the protection core only.. if you have
not used so... I think your system is still safe because
there is not shortcircuit fault tilltime... its very
dangerous if any short circuit occurs... because a metering
CT core is designed in such a way that if there is any
shortcircuit.. it gets saturated and doesnot deliver any
output... if u use this for protection purpose your relay
will not get current(i.e. it gets 0 A which is nothing but
no load condition..). But your relay is set to operate only
in over current conditions... so now what happend.. even in
over current condition, your relay is not getting over
currents hence it will not send any signal to the circuit
breaker...

I suggest, in this regards, u please consult ur higher
authorities...

Ms. minnu, i think we have not studied enough on CTs & PTs
n our basic engineering study...

P.S:
I welcome u both for further clarifications, mail me at
rammy_233@yahoo.com

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