Investigation of effects of short-term thermal stress on pvc insulated low voltage distribution cables

Abstract

The main aim of this study is to investigate the ageing process of Low Voltage cables in smart grid. In addition, the behavior of ageing phenomenon has also been investigated. The Low Voltage cable networks were developed decades ago and it is of utmost importance to make comprehensive study over the health of existing Low Voltage cable networks so as to avoid any unprecedented damage. Incessantly increasing energy demand and distributed generation makes it among top priorities to investigate the ageing process of Low Voltage cables. The effect of thermal stress over dielectrics was investigated as a part of research. To be able to determine these effects the measurements were done on PVC insulated (both cores and jacket) cable by measuring tanδ (dissipation factor), capacitance, return voltage of cable and hardness of insulations. In order to determine thermal effects on dielectric, the measurements were done in different ageing temperature ranges i.e. at 110 °C, 125 °C and 140 °C. The results of this study support the expectations. The mechanical and the electrical parameters of cable insulation are affected by thermal stress. The dissipation factor and the hardness are increased while the decay voltage slope ( Sd ) is decreased by ageing.