Charge injection and storage in cross-linked polyethylene insulated cable

The authors present measurements of the trapped charge in short samples of commercial XLPE (cross-linked polyethylene) insulated power cable. Charge injection was investigated for both AC and DC electric stressing of the samples, for various conditions of temperature and gaseous environment. The injected space charge was examined using three techniques: thermally stimulated discharge current (TSDC), field-assisted TSDC, and the thermal transient current method. These results are compared and the viability of the latter, nondestructive technique to monitor the process of aging in commercial cables is discussed. The presence of a space-charge peak at 60°C in prestressed XLPE insulation is clearly seen using the TSDC method. Field-assisted TSDC illustrates strong ionic conduction at higher temperatures