Partial discharge characteristics of three different epoxy resin potting microdefects

Epoxy resin polymer materials have many advantages, such as high insulation strength, high resistivity, small relative dielectric constant, chemical stability and easy processing. Therefore, it is widely used as external insulation of electrical equipment and made into various insulators or devices. However, due to the limitations of the manufacturing process of the electrical equipment and the curing characteristics of the epoxy resin, there always exist voids inside the epoxy resin or at the interface between the epoxy resin and the metal electrode. Partial discharge (PD) is one of the main reasons for damaging the insulating properties of materials, so it is necessary to study the PD characteristics of epoxy resin microdefects. In this paper, three kinds of epoxy resin defects, namely internal cavity defect, internal crack defect and surface delamination defect, are studied. The experimental results are helpful for the identification of defects of epoxy resin and the evaluation of risk degree in actual production.