Measuring the endurance of films in partial discharges

A new test assembly for measuring the endurance of polymeric and ceramic films under the action of partial discharges (PDs) is presented. If experiments are performed under controlled ambient conditions (i.e., relative humidity), the test procedure gives times to breakdown which show low scatter. The effects of different test conditions on the times to breakdown and relevant data scatter are presented. The adoption of a phase reference PD analyzer (PRPDA) system, together with a video recording system, also gives information relevant to discharge mechanisms and film degradation processes. The test assembly is described and some results, relevant to polymeric films of different thickness, are presented