Temperature Field Calculation and Thermal Circuit Equivalent Analysis of 110 kV Core Cable Joint

In order to indirectly calculate the core temperature of a cable joint, an equivalent transient thermal circuit model of single-core cable joint by considering axial heat dissipation is proposed. Firstly, the temperature field of the middle joint of a 110 kV single-core cable is calculated by finite element method. Based on the heat dissipation path of the core, an improved equivalent thermal circuit model is proposed. The axial heat dissipation of the cable joint core is simplified to a thermal resistance and the temperature rise of the cable body core, the temperature calculation of the cable joint transient process is realized. Compared with the results of finite element simulation, the steady-state temperature errors of the thermal circuit model are within 1 degrees C, while the maximum temperature errors of the transient process shall not exceed 3 degrees C, which proves the validity of the model. This method can provide reference for temperature inversion and the dynamic current-carrying capacity prediction of cable joints.