On the statistical testing of solid dielectrics

The statistical nature of high voltage testing of electrical insulation has long been recognized . A brief overview of the application of statistical methods to establish the insulation strength and life time of solid dielectrics is reported. Accelerated aging tests on solid dielectrics are statistical tests which have to be rigorously analyzed in order to justify any valid conclusions. The application of Weibull statistics for the description of dielectric breakdown is presented. The breakdown probability of the test voltages is a function of the test method, of their parameters, of the nature of the breakdown probability function, and of the assumed physical processes. Proper test methods and their parameters can be selected to determine the breakdown voltages and time to breakdown.