为间接测量土壤直埋电缆中间接头导体线芯的热点温度，通过运用COMSOL仿真软件建立电缆中间接头三维电．磁．热多物理场耦合仿真模型，基于土壤导热系数及其温度和负载电流变化，研究电缆中间接头的温度分布特征。首先通过建立电缆本体及其中间接头等效热路模型，利用轴向热阻构建整体热路模型。之后，将电缆本体及其中间接头表面温度作为输入量，反演计算电缆中间接头导体线芯的热点温度。研究结果表明：负载电流对导体热点温度的影响显著并呈指数增长，土壤导热系数的影响次之，土壤温度的影响相对较小。有限元模型和热路模型计算温度的平均误差为1.89 ℃，从而验证了组合热路模型的准确性和普适性。该研究结果可实现对直埋电缆中间接头导体温度的间接测量，为实时预测其绝缘状态提供有效参考。

In order to indirectly measure the hot spot temperature of the conductor core of the soil buried cable intermediate joint, the three-dimensional of the electromagnetic-thermal multi-physical field coupling simulation model of the cable intermediate joint was established by using COMSOL simulation software. Based on the thermal conductivity of soil and its temperature and load current changed, the temperature distribution characteristics of cable intermediate joints were studied by the multi-physical field coupling simulation model. Firstly, the equivalent thermal circuit model of the cable body and its intermediate joint was established, and the overall thermal circuit model was constructed by using the axial thermal resistance. After that, the surface temperature of the cable body and its intermediate joint were taken as the input to calculate the hot spot temperature of the conductor core of the cable intermediate joint. The results show that the influence of load current on the hot spot temperature of conductor is significant and increases exponentially, followed by the influence of soil thermal conductivity, and the influence of soil temperature is relatively small. The average error of the calculated temperature of the finite element model and the thermal circuit model is 1.89 ℃, which verifies the accuracy and universality of the combined thermal circuit model. The research results can realize the indirect measurement of the conductor temperature of the buried cable intermediate joint, and provide an effective reference for the real-time prediction of its insulation state.