Temperature-dependent effect of gas pressure on electrical tree in XLPE cable

Cross-linked polyethylene (XLPE), which is an important material in the cable insulation, faces the challenge of high temperature with high internal gas pressure during the process of overload. To clarify the impacting mechanism of temperature and gas pressure, this study presents the characteristics of electrical trees and partial discharge (PD) under different gas pressure and different temperature in XLPE cable. Experiments were conducted using XLPE cable insulation as samples. The results show that gas pressure has different effects on the initiation and propagation of electrical trees at different temperatures. XLPE is in the glassy state at low temperature, and the gas pressure suppresses the development of electrical trees during the growth period. When XLPE is in the elastomeric state, the high temperature accelerated the PD under high gas pressure. The analysis shows that more trapped charge and more branch channels will exist at high temperatures with high gas pressure, which is the primary cause behind the development of streamer, thus accelerating the progress of PD. XLPE cable in the case of high temperature and high gas pressure should cause more attention.