Fault development on water ingress in damaged underground Low Voltage cables with plastic insulation

Abstract

Increased pressure on condition monitoring of Low Voltage (LV) underground power cables can be expected due to rising penetration of de-central generation. Digging damage plays a large role in LV cable failure statistics while those damages do not necessarily lead to an outage directly. Artificially damaged cable sections of two commonly used LV cable types have been tested on water exposure. Upon water evaporation, partial discharges occur causing degradation of the insulation material. In one case this was found to lead to breakdown. Several dependencies can be identified that need further investigation. These results enhances the understanding of failure behavior as it may take place underground for cables in service, and can be used in the development of condition monitoring techniques and lifetime predictions.