What is a Protection relay?

A protection relay is a device that instantly detects a sudden change in current or voltage that occurs in power system equipment and sends a control signal to a circuit breaker to isolate the faulty part. Protection relays not only prevent the spread of damage due to overcurrent by quickly isolating the faulty location when an accident occurs in the power system, but also minimize the duration of power outages and provide a stable supply of power. For this reason, equipment accident removal relays for isolating faulty equipment and accident spread prevention relays for preventing the spread of the effects of accidents are distributed in the power system. A reclosing device for quick recovery from an accident is also treated as a type of protection relay.

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