What Is Earth Fault Relay How It Works. These relays are capable of sensing greater fault currents. System at load end in this case is disconnected form source in in case of radial power.
Earth Fault Relay EFR It is a safety device used in electrical installations with high earth impedance. And earth fault relay measures the 3 phases of a Load instead of implementing one current transformer per phase it uses one ground current transformer where the three wires of each phase R S T pass through it. The first stage is arranged to trip the unit transformer circuit-breaker.
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The working principle is allmost same just this relay is capable of sensing greater fault currents. Standby earth fault relays are set to grade with all 11 kV interconnector earth fault protection. The major function of an earth fault relay is to operate for the leakage currents to the earth. And earth fault relay measures the 3 phases of a Load instead of implementing one current transformer per phase it uses one ground current transformer where the three wires of each phase R S T pass through it.
