Identifying Electrical Ageing in Polymeric Insulation

A brief review of the random nature of the processes involved in producing a breakdown path through an insulator suggests that breakdown may occur spontaneously, i.e. without any physical ageing/degradation, especially at high electric fields. This can be supported by considering the distribution function of the times-to-breakdown and, in particular, the shape parameter of the Weibull distribution. The work is supported by data from tests on PET and XLPE and from a preliminary computer simulation.