Partial Discharge Behavior of 110 kV Silicone Rubber Premoulded Cable Joint Induced by Pre-Expanding Installation and Temperature

Several failures of high-voltage and extra-high-voltage cable joints have been reported in China. It is postulated that improper pre-expansion of the cable joints before installation on the cables played a major role in the breakdowns. In this study, the researchers used two 110 k V silicon rubber premolded cable joints as experimental samples. They were subjected to different expansion rates before installation onto a cross-linked polyethylene cable cross-linked polyethylene. Two different specifications of expanding tube were used to expand the joints. Then, withstand voltage tests and partial discharge (PD) tests were done at room temperature and high temperature (95 to 100°C) according to IEC 60885-2. Statistical parameters and patterns were recorded during the test. The joint assembled with an improper expansion rate during pre-expansion installation failed to pass the PD test. The PD behavior was clearly affected by the voltage and temperature during the test. On the basis of these results, the authors propose recommendations for the installation of 110 kV silicone rubber premolded cable joints.