Protective Relay

 Solution:

The device detect the fault and initiate the operation of the circuit breaker to isolate the defective element from the power system.

Types: 

1. Directional relay

    i.Induction type over current relay

    ii.Induction type reverse power relay

2. Differential relay

3. Distance relay (Based on transmission line distance)

    i.Impedance relay

    ii.Reactance relay

    iii.Admittance relay