摘 要 中间接头是电缆线路运行中事故多发的薄弱环节，研究电缆中间接头的传热机理，确定其温度场分布，准确计算载流量，对于保证电缆中间接头运行安全以及提高电缆线路整体可靠性具有重要意义。 本文首先详细说明了配网常用的10kV三芯电力电缆的结构组成，以及电缆接头的分类和发热机理，介绍了电缆的损耗计算方法和传热过程分析，为电缆温度场数值计算提供理论依据。在此基础上，本文利用ANSYS有限元分析软件建立了10kV三芯电缆接头的电磁-热耦合场计算模型，并进行了实例计算。对同一工况下的电缆接头截面温度场和电缆本体温度场分布结果进行了对比，最后又通过现场测量验证了模型的准确性。 进而通过设定电缆接头导体处的接触电阻系数k，建立了计及接触电阻的电缆接头温度场计算模型，研究了电缆接头在接头导体接触电阻过大时的温度特性分布规律，随着接触电阻的升高，接头线芯温度和接头表面温度均逐渐升高。并在温度特性分布规律的基础上，提取了对电缆接头接触电阻系数k进行表征的特征量。最终通过函数拟合的方法得到了对k值大小的表征方法。 本文最后在表征k以及接触电阻仿真模型研究的基础上，提出了考虑电缆接头的电缆载流量计算方法，并比较了数值计算方法和热路解析法的计算结果，最后就环境温度对电缆载流量的影响进行了分析。

ABSTRACT Cable intermediate joint is a weak link in the operation of cable line with many accidents. It is of great significance to study the heat transfer mechanism of cable intermediate joint, determine its temperature field distribution, and accurately calculate the carrying capacity to ensure the safety of cable intermediate joint and improve the overall reliability of cable line. In this paper, the structure and composition of 10kV three-core power cable commonly used in distribution network are described in detail, as well as the classification and heating mechanism of cable joints. The calculation method of cable loss and the analysis of heat transfer process are introduced, providing theoretical basis for the numerical calculation of cable temperature field. The basis of finite element calculation of heat transfer is heat conduction, heat convection and heat radiation. On the basis of this paper, by using ANSYS finite element analysis software established 10 kV three core cable joint electromagnetic-thermal coupling calculation model, and a calculation example is given. Compare the cable joint section temperature field and temperature field distribution of ontology cable results under the same conditions, then the accuracy of the model is verified by field measurement. Then, by setting the contact resistance coefficient k of the connector conductor, the temperature field calculation model of the cable connector that takes the contact resistance into account is established, and the temperature characteristic distribution rule of the cable connector when the contact resistance of the connector conductor is too large is studied. With the increase of the contact resistance, the temperature of the cable core and the surface of the cable connector gradually increases. Based on the distribution of temperature characteristics, the characteristic quantities of joint contact resistivity k were extracted. Finally, the representation method of k value is obtained by function fitting. In the end, based on the research of characterizing k and contact resistance simulation model, the calculation method of cable current-carrying capacity considering cable joints is proposed, and the results of numerical calculation method and thermal path analysis method are compared. Finally, the influence of ambient temperature on cable carrying capacity is analyzed.