Research on Contact Structure in Vacuum Interrupter for DC Breaking Capability

The fast DC vacuum circuit breaker is required that the vacuum interrupter can not only break large current within several milliseconds, but also guarantee the required mechanical life under the condition that the mechanical impact is much larger than that of the AC vacuum interrupter. This paper investigates the DC breaking capability of three typical vacuum interrupters with axial magnetic field contact structure-without slots, with radial slots and with parallel slots by simulation. And the current breaking capability of contacts without slots is proved by prototype test. A test circuit and a method for current breaking capability of fast switchgears are proposed. The research results can provide technical reference for the engineering application of fast DC vacuum switchgears.