Electrical conduction and space charge trapping in highly insulating materials

Abstract

The electrical conduction in low-density polyethylene (LDPE) was investigated in the temperature range from 20°C to 95°C and for applied fields up to 12 MV m−1. The objective was to study the effects of the space charge (SC) accumulated in the material on the low and medium field quasi-steady-state conductivity in LDPE. Very long time (a week or longer) isothermal current measurements were carried out to focus on the situation when the SC effects are dominant. Complementary results were obtained using the isothermal discharge current, the final thermally stimulated discharge current and the isothermal final discharge current measurements. The results are explained by taking into account the constraint imposed by the trapped SC on charge injection, trapping and transport processes.