The role of the arrester is to protect various electrical equipment in the power system from lightning An electrical appliance that is damaged by voltage, operating overvoltage, and power frequency transient overvoltage surge. The types of arresters mainly include protection gaps, valve arresters and zinc oxide surge arresters. The protection gap is mainly used to limit atmospheric overvoltage, and is generally used for protection of power distribution systems, lines, and substation incoming segments. Valve arresters and zinc oxide surge arresters are used for protection of substations and power plants. Systems used in 500KV and below are mainly used to limit atmospheric overvoltage. In ultrahigh voltage systems, they will also be used to limit internal overvoltage or internal overvoltage. Backup protection.