Simulation Analysis of the Electrical and Thermal Characteristics of Water Ingress Defects Within High-Voltage Direct Current Cable Terminals

For maintaining the stable operation of power systems, there is an urgent need to master the electro-thermal characteristics of DC cables. This paper establishes a three-dimensional electric-thermal coupling simulation model of 220 kV cable terminals, and simulates three kinds of operating conditions (no defects, small amount of water intake, and large amount of water intake) of the cable terminals respectively. Based on the simulation results, the electrical-thermal characteristics of cable terminals under defects are analyzed and summarized. The results show that the water ingress defects mainly affect the localized electrical and thermal characteristics of the cable terminal, with less influence on the overall affectivity. Slight increase in average temperature in the area around the defect, accompanied by a distorted electric field with a higher field strength (10% increase for small amounts of water intake, 15% increase for large amounts of water intake). The results of this paper can provide a reference for temperature rise phenomena and insulation design of DC cable terminals.