Influence of film surface on the void discharge deterioration of polypropylene films

This paper investigated partial discharge characteristics in a closed void and void discharge deterioration characteristics of polypropylene (PP) films. It focused on the influence of film-surface structure (rough-surface and smooth-surface) on the deterioration characteristics. The partial discharge characteristic was evaluated by measuring PD patterns (phase-charge-number) under AC voltage application. The PD observation for about 10 hours revealed that the number of PD decreased and then fluctuated, which could be related to the deterioration state of PP film. After the fluctuation, the through-holes of the film were observed. In particular, the area of the through-holes on the film with rough-surface was found to be larger than that with smooth-surface.