We are habituated to use REF protection at the "Y" side of the transformer whose neutral is either solidly ground or resistance ground & ultimately during the fault within the zone the delta side breaker to be isolated.
Recently few consultants are asking to provide REF protection at Delta side also. Now my questions are as under:
1. Is it really a REF to be called as there is no neutral CT for biasing?
2. Instead of REF can we call it high impedance balance earth fault ?
3. How the relay settings vary from "Y" & Delta or both can be same?
4. Any other information with you?
Kindly throw some light.
Restricted Earth Fault Protection at Delta Side 
Re: Restricted Earth fault Protection at Delta side
