Thin solid silicone layers on the surface of model insulators made of resin and their influence on the wet surface performance under high electrical stress

The paper presents investigations on processes occuring on wet and electrically stressed surfaces of insulators made of different epoxy resin systems. When manufacturing insulators in industry a silicone layer covers the surface of the metallic tool in order to enable the separation of the epoxy resin component and the tool. However, due to this a thin layer of solid silicone covets the cured epoxy resin surface as well and superimposes the properties of the insulators surface. This effect is of special importance, when diagnosing the surface conditions of new test specimen and influences the ageing performance of an electrically stressed wet surface. The investigations reported in this paper deal with stressed epoxy resin surfaces manufactured with and without any silicone layer by using special manufacturing technologies