THE DISTRIBUTION OF TRAPPED CHARGES IN LDPE AND HDPE BY ISOTHERMAL POTENTIAL DECAY METHOD

Charactering the distribution of trapped charges and analysis the root causes of the traps within polyethylene is of great significance to control the space charge accumulation and improve the safe and reliable operation of the dc cables. In this paper, the distribution of trapped charges in low density polyethylene (LDPE) and high density polyethylene (HDPE) were investigated based on isothermal surface potential decay (ISPD) method. A non-contact setup was established to conduct corona charging measurement, by which the decay characteristics of the films with varied charging polarity can be obtained. The trapped charge distribution of LDPE and HDPE was obtained by a proposed model. The effects of morphological characteristics of LDPE and HDPE were further analyzed. It is shown that there…