• Prok Devices Private Limited

Earth Fault Relays

Prok Devices offers Earth Fault Relay. This is a current sensing device, which is tropicalised, professionally designed and tested for protection of generators, transformers and feeders. The magnitude of the earth fault current depends on the fault impendence and invariably the fault impedance for earth fault is higher than that for phase faults, hence the earth fault current is low compared to the phase fault currents. The fault impedance depends on the system parameter and also on type of earthing. The neutral may be solidly grounded through resistance or reactance. During the occurrence of earth fault the residual current is non-zero and when it exceeds the pick-up value, the earth fault relay trips. Theoretically during balanced load conditions the EFR carries no current hence its current, setting may be any value greater than zero, but in practice such ideal system do not exist.