Investigation of tracking degradation by DC voltage application

Tracking tests of organic insulating materials of power apparatus for outdoor use have previously been carried out by AC voltage application using stainless steel electrodes. AC voltage has been used for all power engineering apparatus, namely, generation, transmission and household electric products. Recently, this type of apparatus using DC voltage has appeared in various fields. As a result, a solution seemed to be needed for tracking degradation under DC voltage application. This paper describes the investigation of tracking degradation of organic insulating materials for power engineering application. The following results were obtained. Time to tracking breakdown under DC voltage application was long than under AC voltage application. At plus polarity of top electrode, discharge phenomena were stronger than minus polarity. Time to tracking breakdown using a platinum electrode was shorter than that using a stainless steel electrode