Effect of thermal poling treatment on conductance characteristics of DC insulation

In this paper, conductance characteristics of the two kinds of XLPE materials such as XLPE and XLPE/SiO₂ nano-composite were measured under high stresses (2-70kV/mm) and under different temperatures (e.g. 20°C, 50°C and 80°C), after both XLPE were treated through different thermal treatment methods including thermal treatment and thermal poling treatment. The test results show that nanodoped XLPE can increase charge injection threshold and decrease current density effectively, and pre-stressing is facilitate to improve charge injection threshold and reduce current density. Besides, the slopes of both XLPE curves in lgJ-lgE double logarithmic coordinates decrease with the increase of temperature under high fields, indicating the dependence of activation energy of XLPE materials on electrical stress.