Study On Surface Trap And Vacuum Surface Flashover Characteristics Of Typical Polymeric Materials

Surface trapping of insulation materials can participate in the secondary electron emission avalanche (SEEA) development and then affect the surface flashover characteristics in vacuum. To study the relationship between surface trapping and surface flashover, the trap parameters of several typical polymeric materials were deduced based on the isothermal relaxation current (IRC) theory. The surface charging was fulfilled by needle-to-plate corona discharge, and the surface potential was measured by the method of static capacitance probe. The experiment of vacuum surface flashover in direct current (DC) and pulsed voltage was developed, and the relationship between trap parameter and flashover voltage was analyzed. The research results indicate that the trap energy level and trap density of polymeric materials have relation to their flashover characteristics. The shallow trap parameter has more important effect on the flashover voltage, and the flashover voltage decreases with the increase of shallow trap density. The deep trap parameter mainly affects the flashover characteristics after several times of discharges, namely conditioning. The trap parameters have more important effect on the flashover characteristics in DC voltage than in pulsed voltage.