Research on the Influence of Transverse and Axial Magnetic Field Contacts in Vacuum Interrupters on Prestrike Characteristics

Vacuum circuit breakers (VCBs), renowned for their environmentally friendly characteristics, maintenance-free operation, excellent breaking capabilities, and prolonged mechanical and electrical lifespan, are particularly well-suited for reactive power compensation in power systems, thereby possessing significant engineering value. This paper delves into the prestrike behavior of inrush currents when switching back-to-back capacitor banks, utilizing vacuum interrupters (VIs) with two distinct contact structures: transverse magnetic field (TMF) and axial magnetic field (AMF). In the course of the experiments, both types of interrupters were exposed to various magnitudes of inrush currents multiple times, with the prestrike gap and arcing time being recorded during each closing operation. The findings reveal that, under identical conditions, the prestrike gap observed in the cup-shape TMF interrupter is narrower than that in the cup-type AMF interrupter. Nevertheless, when the magnitude of the inrush current reaches 20 kA, the cup-type AMF interrupter demonstrates superior arc extinguishing capabilities. This study serves as a stepping stone for enhancing the prestrike performance of vacuum circuit breakers in the switching of back-to-back capacitor banks in engineering applications.