Power system mainly includes two categories: power generation equipment and power supply equipment. Power generation equipment mainly includes power station boilers, steam turbines, gas turbines, water turbines, generators, transformers, etc. Power supply equipment mainly includes transmission lines, transformers, contactors, etc. of various voltage levels. There are many power equipment in the power system, and according to their different roles in operation, they are usually divided into electrical primary equipment and electrical secondary equipment. Electrical primary equipment refers to equipment that directly participates in the production, transformation, transmission, distribution, and consumption of electrical energy. It mainly includes equipment that produces and transforms electrical energy, such as generators, motors, transformers, etc; Switching appliances that connect and disconnect circuits, such as circuit breakers, isolating switches, contactors, fuses, and other current carrying conductors, as well as gas insulated equipment. Equipment such as busbars, power cables, insulators, wall bushings, etc. that limit overcurrent or overvoltage, such as current limiting reactors, lightning arresters, and other transformer type equipment: Reduce the high voltage and high current in the primary circuit for use in measuring instruments and relay protection devices, such as voltage inductors and current transformers. In order to protect and ensure the normal operation of electrical primary equipment, secondary equipment measures and monitors its operating status Equipment for control and regulation is called electrical secondary equipment. There are mainly various measuring meters, various relay protection and automatic devices, DC power supply equipment, etc