WHY IS RESTRICTED EARTH FUALT PROTECTION NEEDED?? WHY CANT
DEIFFERENTIAL PROTECTION SUFFICE???

Answer Posted / sanjay

REF IS USED TO PROTECT THE SECONDARY WINDING (WYE
CONNECTED). IT GIVES SENSITIVE PROTECTION AS COMPARED TO
THE DIFF PROTECTION.
TO PREVENT MAL-OPERATION OF DIFF PROTN (DUE TO CT ERRORS /
DIFF IN SATURATION CONDITTIONS ETC) AS WELL AS THE
MIN.SETTINGS POSSIBLE IN THE RELAY, DIFF PROTN. CANNOT
OFFER SENSITIVE PROTN.

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