An essential part of electrical systems, a protection relay is responsible for spotting anomalies such as voltage fluctuations, short circuits, and overcurrent. Engineering use: Relays are used on feeders, transformers, buses, motors, generators, and transmission lines to protect equipment and improve system. 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. While this is bad, It's not a. New relays (right out of the package) may be tested for functionality at “minimum specified contact load” or above.