MEASURING THE ENDURANCE OF FILMS IN PARTIAL DISCHARGES

A new test assembly for measuring the endurance of polymeric and ceram ic coated films under the action of partial discharges (PD) is present ed. If experiments are performed under controlled ambient conditions ( i.e. relative humidity), the test procedure gives times to breakdown w hich show low scatter. The effects of different test conditions on the times to breakdown and relevant data scatter are presented. The adopt ion of a phase reference PD analyzer (PRPDA) system together with a vi deo recording system also give information relevant to discharge mecha nisms and film degradation processes. In the paper the test assembly i s described and some results, relevant to polymeric films of different thickness, are presented.