Long term reliability tests of 500 kV XLPE cable system

The prequalification test of 500 kV XLPE cables and accessories has been successfully finished at CEPRI(China Electric Power Research Institute)in partnership with two cable & accessory manufacturers, HANHE and VISCAS. The prequalification test program was aimed at assessing, for the first time in China, the long-term reliability of the 500 kV cable system and in particular the prefabricated joints. The cable system were installed in representative arrangement simulating actual installation conditions used in the underground cable network of China. During more than 8760 h long term test with daily thermal cycling to a maximum temperature of 95°C, key parameters like the voltage, heating current, surface temperature, and SF₆ pressure were monitored. Following the long term test at 493 kV, lightning impulse tests were performed on the complete cable system. The final examination showed that no macroscopical electrical degradation, moisture ingress, leakage, corrosion or harmful shrinkage was found in the cable and accessories.