Research on the impact of water-ingression defects on the electromagnetic-thermal fluctuation and heat distribution characteristics of high voltage cable terminals

High voltage cable terminals (HVCT) usually work outdoors with water-ingression defect which affects the normal operation of the power system. This paper presents the study of the influence of different water-ingression depth on the temperature distribution of HVCT. Firstly, the model of EM-thermal-fluid coupling field of HVCT was established using finite element method in line with the structural parameters of YJZWC4 HVCT. Subsequently, the effectiveness of the model is verified by comparing the operation of the model under the actual HVCT. Then, the electromagnetic characteristics and temperature characteristics of HVCT are calculated, reacted and detected by the model. The analysis results of temperature show that the surface temperature of HVCT at inlet part is significantly higher than that of the insulating oil part. And the influent depth is positively correlated with surface temperature and temperature gradient. The distortion of the electric field will be more serious due to the deepening of the depth of the inlet water. The research results accurately reflect the electromagnetic thermal characteristics of the HVCT under the influent state. It provides a mathematical fitting expression for the cable terminal model, and provides a technical means for the state prediction and fault diagnosis of cable terminals.