Research on the Insulation Performance of XLPE Cables with Different Service Years

XLPE cables, as key equipment for transmitting electrical energy in power systems, have insulation performance that directly affects the safe and stable operation of power grids. This paper takes 110 kV retired XLPE cable segments that have not been in service, have been in service for 3 years, 10 years, and 20 years as the research objects. Through power frequency dielectric loss measurement, breakdown experiments, and differential scanning calorimetry (DSC), the variation law of insulation performance with service years is explored. The results show that the overall power frequency dielectric loss increases with the service years; the breakdown voltage shows significant differexnces at a low voltage rise rate of 1 kV/min, with the 20-year cable being 8.01% lower than the unaged cable, while the difference is only 1.28% at a high voltage rise rate; DSC tests show that the peak temperature of the thermal history of the 20-year cable reaches 96.28 °C, significantly higher than that of cables of other service years, indicating that long-term service experiences higher thermal stress. The study reveals the aging law of XLPE cable insulation performance and provides a reference basis for cable condition assessment.