Effect of temperature on partial discharges activity and electrical trees propagation in XLPE

Abstract

Cross-linked polyethylene (XLPE) cables are commonly used for constructing urban power lines due to their superior properties. Insulation defects can cause partial discharge (PD) and electrical tree, which can negatively impact the insulation performance of the cable and even lead to insulation failure. During operation, cables undergo hot and cold cycles, and the temperature of the insulation layer can affect the PD and electrical tree. An experimental platform with a needle-plate electrode was developed to investigate this phenomenon. The platform was used to detect PD activity and electrical tree propagation in XLPE under a 50 Hz voltage at various temperatures. The results indicate that an increase in insulation temperature leads to an increase in the number of PDs and a decrease in the inception voltage. Simultaneously, it has been observed that a rise in temperature can facilitate the spread of electrical trees. To explicate the aforementioned PD result, a finite element analysis (FEA) model has been developed. Additionally, a molecular dynamics (MD) model of XLPE material was developed to clarify the phenomenon of electrical tree propagation. This study's findings aid in investigating the impact of temperature on XLPE defects, which is critical for assessing power cable performance.