Isolation switch (commonly known as "knife gate"), generally refers to the high-voltage isolating switch, that is, the isolating switch with rated voltage of 1kV and above, usually referred to as the isolating switch, is an electric appliance used in high-voltage switchgear, it is more The working principle and structure of the system are relatively simple, but due to the large amount of use and high reliability requirements, the impact on the design, establishment and safe operation of substations and power plants is large. The main feature of the isolating switch is that it has no arc extinguishing capability, and can only divide and close the circuit without load current. The isolating switch is used for voltages at various stages. It is used to change the circuit connection or isolate the line or equipment from the power supply. It has no current-breaking capability. It can only be disconnected before operation by other equipment. Generally, there is an interlock device that prevents the switch from being erroneously operated with a load, and sometimes a pin is required to prevent the switch from being opened under the action of a large fault magnetic force.