QUESTION
What does standby earth faulty protection do on a transformer and the circuit at large?
REPLIES
raghun
SBEF protection is connected to neutral CT of the transformer and works as standby protection to the earth faults downstream as well as for the incomer cable and transformer secondary winding earth faults.
REF protection is unit protection for a set of windings (primary or secondary, depending on CT locations).
SOURCE
https://www.eng-tips.com/viewthread.cfm?qid=442495
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