Dependence of Short Circuit Breaking Current on its Minimum Arcing Times of a Fast Vacuum Circuit Breaker

The objective of this paper was to investigate the influence of root-mean-square value of a short-circuit breaking current on its minimum arcing times of a fast vacuum circuit breaker (FVCB), when it was engaged to clear a short-circuit fault. A vacuum interrupter with a pair of cup-type axial magnetic field contacts was used. A Weil synthetic test circuit was used to provide a test current ranging from 20 to 40 kArms, and a transient recovery voltage (TRV) of 92 kV/ 120 μs. An electromagnetic repulsion actuator was used to drive the vacuum interrupter, with an opening velocity ranging from 2.67 m/s to 4.13 m/s. Furthermore, the postarc current was measured by a high-resolution current-zero diagnostic system. Experiment results showed that with the increase of the root-mean-square value of the short-circuit breaking current, the minimum arcing time of the FVCB increased. However, the lasting time of the post-arc current has little been influenced by the breaking current rather than the arcing time in short-circuit interruption process. Test results would contribute to a controlled short-circuit interruption of a FVCB.