Dielectric breakdown of low density polyethylene film subjected to partial discharge in air gap

Polymeric materials such as polyethylene and polypropylenes are widely used as electrical insulating materials of power cables and capacitors because of their excellent electrical and mechanical properties. Normally, once they are charged, these charges are supposed to maintain for a long time and the possibility of various problems arises, which relate to the static or surface charges. In this paper, we investigated the dielectric breakdown and space charge formation of a low-density polyethylene (LDPE) film caused by partial discharge in air gap. The highest Fb was obtained with the specimen film without a gold evaporated electrode on the needle electrode side. When the gold evaporated electrode was deposited on the surface of the film, the Fb decreased with increased evaporated electrode area. The Fb decreased with relative humidity above 75%.