High-Current Vacuum Arc Shunted by a Semiconductor Switch on Kiloampere Current Interruption

This paper reports on the study of physical processes in a high-current vacuum arc shunted by semiconductor elements. The switching dynamics between a vacuum circuit breaker (VCB) and an assembly of several semiconductor elements connected in parallel to the VCB is investigated. The breaking capacity of a VCB-thyristor system is analyzed. It is found that at the instant of current switching, the arc can operate at a rather low voltage of 8-10 V. It is shown that there exists a certain limiting mode close to the conditions for current switching. In this mode, at least two cathode spots are observed.