CHEN Daoyuan, YANG Mingyuan, NIE Yongjie, HUANG Bo, WANG Jiayin, ZHAO Xuetong
With the development of power distribution systems and the acceleration of urbanization, power cable transmission is advancing toward higher loads, safety, and reliability. The cable branch box, as an essential component of the distribution network, houses the 10 kV T-type cable joint, which serves as a core element within the box. The operational state of the T-type cable joint directly affects the safety and reliability of the power system. Based on the finite element analysis method, this study employs COMSOL Multiphysics software to establish a three-dimensional electro-thermal-fluid coupling model of the cable branch box and its internal T-type cable joint. The work investigates the effects of current load, ambient temperature, airflow velocity, and the number of ventilation openings on the temperature field distribution of the joint. The results reveal that variations in current load lead to a nonlinear increase in the joint temperature, the rise in ambient temperature significantly amplifies the temperature increase of the joint, and ventilation conditions present a more pronounced effect on the temperature field distribution. Specifically, airflow velocity within a certain range greatly enhances cooling performance, but the cooling effect saturates beyond a threshold. Additionally, increasing the number of ventilation openings improves cooling efficiency, especially under high-load operating conditions. This study provides theoretical support for the optimization of cooling systems in cable branch boxes and offers valuable insights for the operational management and fault prevention of cables and T-type cable joints.