Investigation of the Partial Discharge Behavior in the Border and Edge Area of thin Film Electrodes in Layered Isolation Systems

One typical problem in the development of layered insulation system (e.g. electrical bushing) is the border and edge areas of the electrode (e.g. aluminium foil) which are known as the weak point for the electrical behaviour. Because of the geometry of the design results an air area as a triple point between the aluminium and plastic-film. A partial discharge at the triple point can lead to damage in this insulation system, so it is necessary to test the partial discharge behaviour at the border and edge area under the influences of different filling materials. With the results of partial discharge tests, the influencing factors and behaviour of the electrical field strength can be described.