Characteristics of leakage current and flashover on epoxy resin insulator

Insulation is an important part in an electric power system. There are many materials used as insulation in electric power equipment. Epoxy resin is a kind of polymeric insulation which is used as indoor as well as outdoor insulators. Under operating condition and polluted environment a large leakage current (LC) may flow on the surface. The LC may degrade the insulator surface and in the long time it may lead to the flash over. This paper reports experimental results on the LC characteristics of epoxy resin insulation. The samples used are epoxy resin blocks with dimension of 250 × 50 × 20 mm³. The samples were tested in a chamber with controllable artificial environment. AC voltage was applied and LC waveforms were measured. The digital data of LC was transferred to a computer for further analysis. The correlation between LC waveforms and dry band arching phenomenon under various environmental conditions was elaborated.