Surface Charge and Flashover Voltage of Fluorinated Polypropylene Film under DC and Pulse Voltages

Abstract

Polypropylene (PP) film is extensively employed as the dielectric in film capacitor because of its advantages of low loss and high dielectric strength. Surface charge that accumulated on PP film can cause electrical filed distortion and induce surface flashover when under DC and pulse voltage, which accelerate electrical aging of a capacitor. This paper investigated the surface charge accumulation and surface flashover voltage under DC voltage and pulse voltage and a modification method to inhibit the accumulation of surface charge. Samples that were fluorinated for 15, 30, 45 and 60 min and original samples were prepared prior to the experiments. Samples were corona charged with a pair of needle-plate electrodes. The transportation of surface charges was analyzed by the calculation of the carrier mobility. The flashover experiments were performed under combination of DC voltage and pulse voltage in atmospheric air. The results indicate that the minimum surface charge accumulation and maximum flashover voltage can be obtained when the samples are surface modified for 45 min.