Comparative study of conductivity in mid-voltage cable XLPE insulation

It is well established that space charge conditions insulation lifetime. Because of this, space charge formation and relaxation processes characterization has become a very active research field, not only from an basic science point of view, but also in order to improve insulation performance in cable and other devices. In the case of mid-voltage power cable, crosslinked polyethylene is widely used as insulator. Service temperature of such cables is around 90degreesC, which in the case of the cable insulation studied is in the melting temperature range. In previous works it has been determined that at this temperature conductivity plays a relevant role in the space charge relaxation process, so that the characterization of conductive processes at service temperature may become important in order to enhance cable insulation performance. The aim of this work is to contribute to a better knowledge of the conductive properties of XLPE in both time and frequency domains.