Study of a 40.5kV/50kA Vacuum Interrupter Used for the Current Limiter

Vacuum circuit breakers are widely used in medium and low voltage power system. This article is based on the national key R&D project "Development of economical high-voltage AC current limiter for voltage levels of 500kV and above", which mainly studies a 40.5kV/50kA vacuum interrupter(VI). The special VI was used for the current limiter to interrupt the arc under the conditions of higher DC component and shorter arcing time. In order to obtain the structures of the contacts and the repulsion mechanism, lots of magnetic simulating calculations were carried out. A 2/3 coil-type contact structure was used in this paper. Then, a 40.5kV/50kA VI with the 2/3 coil-type contact structure was designed by electric field simulating calculations. A fast repulsion mechanism was used as the driving component to carry out the rated symmetric short-circuit current breaking test (T100s) and the rated asymmetric short-circuit current breaking test (T100a) under the parameters described in the paper. At present, the VI designed in this paper could successfully break the rated short circuit current of 50kA, and the DC component of T100a was 78%.