Experimental investigation of surface flashover of PMMA, HDPE and PA in vacuum using 180 nanosecond quasi-square pulses

An experimental investigation of surface flashover characteristics in vacuum pressure of 1.3×10-2 Pa (10-4 Torr) was introduced by using a quasi-square pulse generated by an intense electron beam accelerator (IEBA) with duration of 180 ns and voltage of 180-300 kV, and the gap spacing length was varied from 100 to 210 mm. Polymethyl methacrylate (PMMA), High density Polyethylene plastics (HDPE) and Polyamide (PA) were chosen as the investigating insulator dielectrics in this paper. The effects of insulator material, applied voltage and gap spacing length on the surface flashover characteristics are presented. Meanwhile, the delay time, flashover current and impedance of the flashover channel are also discussed.