Breakdown strength at the interface between epoxy resin and silicone rubber-a basic study for the development of all solid insulation

As a key component for a future power substation system entirely consisting of solid insulating materials, a special connection system between different pieces of power equipment has to be developed. A soft dielectric such as silicone rubber and a hard one such as epoxy resin are to be used for this connection. This paper describes the interfacial breakdown strength between silicone rubber and epoxy resin using two types of model samples on which the electric field can be applied in parallel or perpendicularly to their interface. Partial discharge characteristics at the interface and the effect of air penetration on the breakdown voltage along the interface are discussed.