Earth Leakage Relay

Additional Details

Description :

This relay is used on AC systems and is a sensitive electronic protective device. Its operation on Earth fault is independent of the system voltage imbalance. This relay can detect Earth fault currents as low as 1 amp. This is 0.25% in a 400 amps feeder system. This can be used on a single phase or on a three-phase network.

Principle of operation :

This relay operates on the core balance principle wherein the currents in the three phase of the system are summed by a core balance C.T. which for normal conditions equates to zero. In case of a leakage current to earth this balance is disturbed causing the electronic circuit to operate a relay within the unit. In this event the relay that is generally connected to circuit breaker operates thus tripping the main circuit. The electro mechanical relay operates on fault. The Earth Leakage Relay is provided with a TEST push button for checking its operation and a RESET button to reset the relay on operation. This helps in checking the proper functioning of the relay.