Relay protection is an important measure to detect faults or abnormal conditions in power system, so as to send out alarm signals or directly isolate and remove the fault parts.

This paper studies the faults and abnormal working conditions that endanger the safe operation in power system, so as to explore its countermeasures and anti-accident automation measures. During its development, it is mainly used to protect the power system and its components (generators, transformers, transmission lines, etc.). ) from damage, so it is also called relay protection.

The basic task is to automatically cut off the faulty equipment from the power system in the shortest possible time and in the smallest possible area, or send a signal to the personnel on duty to eliminate the root causes of abnormal working conditions, so as to reduce or avoid the damage of equipment and the impact on the power supply in neighboring areas.