Over current protection is practical application of magnitude relays since it picks up when the magnitude of current exceeds some value (setting value ). There are four types of over current relays.
Instantaneous Over Current Relay
Instantaneous over current. Relays which operation criteria is only current magnitude (without time delay) as shown in figure (9). This type is applied to the out going feeders. The connection diagram of instantaneous over current relay is shown in figure (10).
Instantaneous over current. Relays which operation criteria is only current magnitude (without time delay) as shown in figure (9). This type is applied to the out going feeders. The connection diagram of instantaneous over current relay is shown in figure (10).
