Prestrike inrush current arc behavior in AMF vacuum interrupters subjected to contact plate slots

Abstract Inrush current prestrike arcs can cause local surface melting of contacts in vacuum interrupters (VIs) and cause strong contact welding during capacitive load operations. The contact welding rupture would seriously damage the appearance of the contact surface and lead to a high restrike possibility during the next opening operation. The slots on the contact plate can remarkably influence the inrush current prestrike arc behavior. The objective of this paper is to research the influence of contact plate slots on prestrike inrush current arc behavior during the capacitive-making processes of VIs. The experimental results showed that the no-plate-slot VIs had better performance than the VIs with plate slots during the prestrike arcing process. In addition, according to the simulation results, the AMF flux density in the arc region is lower in the VIs with plate slots than in the VIs without plate slots at the peak of 20-kA amplitude inrush current, which together with the effect of the slots contributes to the stationary intense arcs in the VIs with plate slots.