Partial discharge behavior of 220 kV prefabricated cable termination induced by inadequate interface pressure

Several high-voltage and extra-high-voltage cable termination failures have been reported in China. It is postulated that inadequate interface pressure between the stress cone and cable insulation played a major role in the breakdown. In this study, the researchers used a 220 kV silicon rubber integral prefabricated cable termination as the experimental sample. A pressure sensor made of thin film was deployed to measure the interface pressure under different cases that simulated the improper installation in which the termination contacted the cable with different pressures. The epoxy sleeve was stripped from the stress cone and the screws of the stress cone holder were adjusted to apply different interface pressures between the cable and the termination. Then, withstand voltage tests and partial discharge tests were conducted. The results indicate that the assembled termination with inadequate interface pressure could fail to pass the withstand test and partial discharge test. Based on these results, the authors proposed recommendations about the installation of 220 kV integral prefabricated silicone rubber cable terminations.