Is the Differential Protection on transformer provides protection outside the protection zone ?

Generally Differential protection of a transformer is designed to operate fault within the protected zone. It will not operate out side Zone fault, but if outside zone fault is to huge & to avoide Saturation of CT's may mal operation the Relays, to prevent that we tend to use slope/bias characteristics or stabilizing resistor or metrosil etc according to nature of protection

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No, Differential Protection does not provide protection otuside the zone. It compares the phase difference and magnitude entering and leaving the protected zone. Differential relay works on the principle of Kirchoff's current law, the differential current measured between incoming and outgoing current must be negligible during stable condition, in case of fault the relay will sense the differential current and initiate breaker trip.

The Differential Protection does not Provide protection outside the differential zone.

No the Differential Protection provides protection to Inside the differential Zone Only. any fault outside the zone will not be protected.