Protective relays are used to detect abnormal electrical conditions, such as short circuits, overloads, and ground faults, in power systems. They are intended to quickly identify a fault and isolate it so the balance of the system continue to run under normal conditions. This prevents damage to equipment, reduces downtime, and safeguards. A protective relay is an intelligent electrical device designed to detect faults in power systems and initiate corrective actions such as tripping a circuit breaker. Advantages, over current relays, directional relays, distance relays.