Partial discharge deterioration of polypropylene films with different film-surface structure

This paper investigated the deterioration characteristics of polypropylene (PP) films due to partial discharge in a closed void filled with air as a basic study by focusing on the influence of the roughened PP-surface on the deterioration characteristics. The PD experiment was carried out under AC voltage application with the sphere-plane electrode system which had a closed void of PP films. The measurement of PD pattern for 10 hours revealed that the number of PD decreased monotonically and then fluctuated, which could be relate to the deterioration state of the film surface. On the surface of the deteriorated film, many deterioration products and through-holes were observed. FT-IR analysis of deterioration products could indicate oxidation degradation or decomposition of PP by PD exposure. The through-holes were found after the fluctuation of PD number started. The area of the hole on rough surface of PP was found to be larger than that on smooth surface, suggesting that the rough surface is easier to be damaged by PD.