106 / 2021-06-05 23:49:10

SIMULATION OF SPACE AND INTERFACE CHARGE ACCUMULATION BETWEEN EPOXY RESIN AND SILICON RUBBER

With the rapid development of high voltage direct current (HVDC) projects in China, there is a growing trend in the demand for cable accessories. Cable accessories are usually insulation systems which consist of several kinds of dielectrics. However, the charges are probable to accumulate in the bulk of dielectrics and between the interface of different dielectrics, which will cause electric field distortion and insulation failures. More than 70% accidents that occurred in power cable systems was caused by the faults of cable accessories according to statistics. It is necessary for us to investigate the mechanism of accumulation of space charges and interface charges. Here, the bipolar charge transport model was used to investigate the properties of injection, transportation and accumulation of space and interface charge in the simplified double-layered insulation system consists of epoxy resin (EP) and silicon rubber (SiR) by considering the parameters such as interfacial potential barrier and carrier mobility in EP. It was found that interfacial potential barrier, carrier mobility and charge injection barrier would all influence the distribution of space and interface charge in dielectric insulation systems while the influences of different parameters are different. According to the simulation results, the decrease in carrier mobility and increase in charge injection barrier between electrodes and dielectrics will decrease space charge accumulation. The injection barrier will influence injection of carriers and hence influence the accumulation of space and interface charges. And electrons and holes are more likely to go through the interface regardless of interfacial potential barrier.