The Roof Cable Terminal Simulation Calculation Study Based on Electric-Thermal Coupling Physical Field

The roof cable accessories of the motor train unit are affected by various factors such as electricity, heat and airflow. Conducting simulation and calculation research based on electric-thermal coupled can effectively guide product development. Also, it can provide technical support for product fault operation and maintenance. The electrothermal coupled simulation model of roof cable terminal is established. The electric field distribution and temperature field distribution of the cable terminal at room temperature and the influence of ambient temperature on the electric-temperature field are studied respectively. The simulation shows that the change of terminal electric field caused by temperature is not significant, and the maximum distortion point occurs at the triple junction point, which is 4.54 kV/mm. The electric field is mainly distributed at the main insulation of the cable, and the electric field strength is 4.10 kV/mm. At steady state, the maximum temperature near the wire core is 47.0 °C. The temperature of the insulating layer decreases in a gradient from the inside to the outside. The temperature of the umbrella skirt part was 26.2 °C. In addition, the ambient temperature has a large impact on the temperature distribution at the terminals. Temperature differences and differences in the thermal conductivity of different materials can create temperature gradients inside the terminals. The change in the internal electric field of the terminal due to temperature change is small in comparison. The work is a guideline for the design and fault analysis of roof cable terminals for motor train units.