Study on Insulation Performance of Thermal Aging XLPE Cables by Direct Current Integrated Charge Technique

Abstract

The effect of thermal aging on the insulation performance of XLPE cables is studied using a new diagnosis technique-direct current integrated charge (DCIC-Q(t)). The influence process of thermal aging on crosslinked polyethylene (XLPE) and the measuring principle of DCIC-Q(t) were described. Several thermal aged XLPE cables were obtained for DCIC-Q(t) experiments. The dynamic charge curve of cables under different thermal aging conditions is obtained, and charge ratio $R$ is proposed to compare the charge injection and accumulation. The permittivity $\varepsilon_{r}$ and conductivity $\gamma$ of XLPE insulation are calculated to analyze the aging level of XLPE cable insulation. It can be concluded that this technique can be useful to monitor the aging of the full-sized cable and has potential to applying in other insulation system.