Differential Relay

Differian Relay input is from CT's connected at Transformer both winding like for 11/0.440KV transformer 3 CT's on 11kV I/C and 3 CT at 440V O/G and relay in coordiantes between this and monitors paramers like U,I,F & Impedence of Winding . Main purpose of this relay is to monitor impedance of both the windings which effects on parameters like U,I,F & give protection in case mismatch of windings.

Differntial relay input is from CT's connected at both the windings like on 11/0.440KV transformer ct's are connected at 11 KV and 440V side of the transformer. This relay monitors the impedance of all windings and if any winding goes outof sync it will trip the 11kv breaker and save the transformer.

Differential protection is a unit-type protection for a specified zone or piece of equipment. It is based on the fact that it will operate only in the case of faults internal to the zone that the differential current (difference between input and output currents) will be high. Differential elements compare an operating current with a restraining current. The operating current (also called differential current), Id, can be obtained from the phasor sum of the currents entering the protected element:

Id = W₁+W₂

Differential protection is used to protect the windings of a transformer by comparing the current between the primary and secondary of transformer. if the currents are

equal then the differential protection relay will not operate; if there is a current imbalance then the differential protection relay operates.

Vinu, you have been advised before.

When using material from some source you must give credit to that source, or, better still, give the link to that document so that the OP can get full benefit of that document/webpage.

Like this : http://www.emo.org.tr/ekler/ff75f52998a477f_ek.pdf

Thanks, your suggestion will be considered. Like this,

Follow links:

http://xnet.rrc.mb.ca/janaj/differential_protection.htm

http://electricalandelectronics.org/2009/03/19/differential-protection-in-transformers/

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