The Electrical Behaviors of the Interface in Solid-Insulated Distribution Equipments

Solid-insulated distribution equipment has several design advantages when considering benefits for environmental protection, maintenance-free operation, compact-design, light weight etc. In such equipment, interfaces between different solid insulating materials are generally inevitable. The interface, depending on the placement in the equipment, is not only subjected to high electric field stress perpendicular to the interface but also to electric field stress parallel to the interface. It is therefore very important to achieve an interface with robust electrical performance in both directions. In this paper, the electrical properties of the interface subjected to the parallel electric field have been investigated. Two different types of interface samples were intentionally chosen: one composed of silicone rubber and EPDM rubber - a soft-soft type interface and the other composed of silicone rubber and fiber reinforced epoxy resin - a soft-hard type interface. Samples were evaluated for leakage current and electrical breakdown behaviors. The purpose of the research is to determine if there is a significant difference in electrical performances between the two types of interface samples accordingly. The results have been discussed.