Experiments and Simulations on Influencing Factors of Pulsed Surface Flashover in Vacuum

The pulsed flashover strength of epoxy composite material in vacuum is related to the vacuum level, the electrode material, the relative dielectric constant, and the surface charging quantity of the sample. By using a high power single pulse generator (65ns rise time, 600ns half-height pulse width time and 10-4Pa ultimate vacuum level), the vacuum surface flashover characteristics of epoxy and epoxy/Al2O3·3H2O composite material are studied by using the fingertype electrode with different materials (brass, duralumin and stainless steel). In the case of stainless steel-stainless steel fingertype electrode system, the flashover experiments under different vacuum level are investigated. Based on the ANSOFT Maxwell 3D software, E-field distribution of the electrode system, the effect of the relative dielectric constant of the sample on the maximum value of E-field magnitude and the role of surface charging of the sample on the maximum value of E-field magnitude are simulated and discussed.