The Mainly use in the electric power system of 50Hz, 40.5kV alternating current, and use in breaking negative current, empty load transformer, cable current, electric capacity current, controlling short-circuit breakdown current.

It forms transformer protection switch in cooperation with fuse box, and the transformer protection switch has stronger switching capability, vacuum arc quench, longer mechanical life, which can be operated by hand and electrodynamic force. It forms intellectual separator equipped with controller, the intellectual separator is widely used in the distribution automatic system, transformer substation watched by nobody.