switchgear refers to the voltage of 1 kv and above krag system running in indoor and outdoor ac switch toerusting, mainly used in electric power system (including power plants, substation, transmission and distribution lines and industrial and mining enterprises and other users) of the control and protection, as well as the werking of the power grid need to be part of the electrical equipment or lines into or out of operation,  Can also be in the power equipment or line failure when the fault part from the power grid quickly cut, so as to ensure the normal operation of the power grid without fault part and the safety of equipment, operation and maintenance personnel.