Abstract
Recently, the need of using of direct molded (DM) air bushing in cable end terminals and transformers are increasing due to its merits of lighter weight and simpler structure comparing to the porcelain bushing. It uses epoxy resin as the main insulation material around the main conductor. Despite several merits of using epoxy resin, the field concentration around the shield fittings occurs which may cause electricity failure and insulation degradation. For the field controlling, an approach has started to use the Zinc Oxide (ZnO) microvaristors in epoxy resin. However, the measurement of electrical properties of epoxy resin filled with ZnO microvaristors exposed in high voltage (HV) is not easy. So, we have approached with circuit simulation method to understand the electrical properties of ZnO particles while injected in epoxy sheet by LTspice circuit simulator. Epoxy sheets with different volume fraction of ZnO particles were proposed and their equivalent circuits were prepared. The simulation results showed the relationship between their electrical properties with the amount and distribution of ZnO particles in epoxy sheet under HV application.
