Abstract：As an important part of the prefabricated cable terminal, the stress cone structure can alleviate the concentration of the electric field strength at the cut-off of the insulation shielding layer during the operation of the cable terminal. However, in the installation and construction of the cable terminal, due to the influence of the installation process and operating conditions, the cable terminal will have a stress cone dislocation defect, which will affect the uniform distribution of the terminal electric field; at the same time, the increase in cable core and insulation temperature will lead to a change in the thermal stress distribution in the terminal and affect the thermal stress distribution in the terminal. At present, the research on cable terminal defects mainly focuses on electro thermal aspects, while there are few studies on their internal stress distribution. In this paper, the electro-thermal-mechanical multi-physical field coupling simulation analysis of the dislocation defect cable terminal is carried out to analyze the changes in electric field strength, temperature distribution, and stress distribution in the operation of terminal defects. During the operation of the cable terminal, the heat source is formed due to the electromagnetic loss, which leads to the change of the internal temperature of the terminal, and then the thermal stress and deformation of the terminal are generated by the thermal expansion of the material. Firstly, the physical field control equations of the cable terminal are established and the coupling relationship between the physical fields is analyzed. Then, the cable terminal model and the stress cone dislocation defect model are established, and the material parameters and boundary conditions are set and simulated. Finally, by comparing the maximum electric field strength, temperature change, and interface pressure distribution under the condition of a cable terminal defect, the influence of a stress cone dislocation defect on terminal temperature and stress is obtained, and suggestions are given for cable terminal installation, operation and maintenance. The simulation results show that when the cable terminal is in normal operation, the electric field strength of the insulation interface changes abruptly at the cut-off position of the shielding layer. The maximum temperature of the terminal cable core is 312 K, and the maximum thermal stress is 1.37×107 N/m2. The terminal interface temperature and interface pressure are abruptly changed at the cut-off position of the insulation shielding layer. When the installation size of the cable terminal is too small, the maximum electric field strength of the insulation interface is 2.25 MV/m, and the electric field rise zone appears between the cut-off of the insulation shielding layer and the root of the stress cone. When the dislocation size of the cable terminal is -7.5 mm, the temperature of the insulation interface reaches its highest value. When the terminal dislocation size is -2.5 mm, the insulation surface pressure value is the largest, reaching 3.78×105 N/m2. When the dislocation size of the cable terminal is +7.5 mm, the maximum electric field intensity of the insulation interface increases to 2.42 MV/m, and distortion occurs at the truncation of the insulation shielding layer. When the installation size of the terminal is too large, the sudden change in the interface temperature will increase, the pressure of the cable terminal on the insulation surface will increase, and the pressure of the insulation interface will be obviously distorted. When the dislocation size of the cable terminal is +5.0 mm, the insulation interface pressure reaches a maximum of 3.46×105 N/m2. According to the above conclusions, the dislocation defect of the cable terminal will seriously affect the stress distribution of the terminal and superimpose with the electric field and temperature field, resulting in terminal insulation damage and aging. Therefore, the design and installation of the cable terminal should pay attention to the occurrence of stress cone dislocation defects, especially to avoid the electric field distortion and stress distortion caused by the excessive installation size of the terminal.
[1] 李国倡, 梁箫剑, 魏艳慧, 等. 配电电缆附件复合绝缘界面缺陷类型和位置对电场分布的影响研究[J]. 电工技术学报, 2022, 37(11): 2707-2715. Li Guochang, Liang Xiaojian, Wei Yanhui, et al.Influence of composite insulation interface defect types and position on electric field distribution of distribution cable accessories[J]. Transactions of China Electrotechnical Society, 2022, 37(11): 2707-2715. [2] 刘凯, 张鹏鹏, 高波, 等. ZnO@PS粒子分散特性及改性乙丙橡胶绝缘性能研究[J]. 电工技术学报, 2023, 38(8): 2265-2276. Liu Kai, Zhang Pengpeng, Gao Bo, et al.Research on the dispersion characteristics of ZnO@PS particles and the insulation characteristics of modified ethylene propylene rubber[J]. Transactions of China Electrote-chnical Society, 2023, 38(8): 2265-2276. [3] 何金良, 杨霄, 胡军. 非线性均压材料的设计理论与参数调控[J]. 电工技术学报, 2017, 32(16): 44-60. He Jinliang, Yang Xiao, Hu Jun.Progress of theory and parameter adjustment for nonlinear resistive field grading materials[J]. Transactions of China Electrotechnical Society, 2017, 32(16): 44-60. [4] 韩宝忠, 傅明利, 李春阳, 等. 硅橡胶电导特性对XLPE绝缘高压直流电缆终端电场分布的影响[J]. 高电压技术, 2014, 40(9): 2627-2634. Han Baozhong, Fu Mingli, Li Chunyang, et al.Effect of silicone rubber’s electric conductance characteristic on electric field distribution inside XLPE insulated HVDC cable termination[J]. High Voltage Engineering, 2014, 40(9): 2627-2634. [5] 胡军, 赵孝磊, 杨霄, 等. 非线性电导材料应力锥改善电缆终端电场强度分布[J]. 高电压技术, 2017, 43(2): 398-404. Hu Jun, Zhao Xiaolei, Yang Xiao, et al.Improving the electric field strength distribution of cable terminals by stress cone of nonlinear conductivity material[J]. High Voltage Engineering, 2017, 43(2): 398-404. [6] 李长明, 伍国方, 李春阳, 等. XLPE绝缘高压直流电缆终端内缺陷对电场分布的影响[J]. 电机与控制学报, 2018, 22(12): 62-67. Li Changming, Wu Guofang, Li Chunyang, et al.Effect of the defects inside XLPE insulated HVDC cable termination on the electric field distribution[J]. Electric Machines and Control, 2018, 22(12): 62-67. [7] 黄韬, 郝艳捧, 肖佳朋, 等. 10kV XLPE电缆终端典型安装缺陷的工频局部放电特征对比研究[J]. 电网技术, 2022, 46(6): 2420-2428. Huang Tao, Hao Yanpeng, Xiao Jiapeng, et al.Comparative study on partial discharge characteristics of typical installation defects in 10 kV XLPE cable terminals under power frequency[J]. Power System Technology, 2022, 46(6): 2420-2428. [8] Ciuba M, Wojciechowski M, Owsiński M, et al.Excitation type and results of simulated electric field distribution in MV cable termination[J]. Przegląd Elektrotechniczny, 2020, 96(4): 119-122. [9] 李国倡, 王家兴, 魏艳慧, 等. 高压直流电缆附件XLPE/SIR材料特性及界面电荷积聚对电场分布的影响[J]. 电工技术学报, 2021, 36(14): 3081-3089. Li Guochang, Wang Jiaxing, Wei Yanhui, et al.Effect of material properties of XLPE/SIR and interface charge accumulation on electric field distribution of HVDC cable accessory[J]. Transactions of China Electrotechnical Society, 2021, 36(14): 3081-3089. [10] 魏艳慧, 郑元浩, 龙海泳, 等. 绝缘层厚度对高压直流电缆电场和温度场分布的影响[J]. 电工技术学报, 2022, 37(15): 3932-3940. Wei Yanhui, Zheng Yuanhao, Long Haiyong, et al.Influence of insulation layer thickness on electric field and temperature field of HVDC cable[J]. Transactions of China Electrotechnical Society, 2022, 37(15): 3932-3940. [11] Zachariades C, Peesapati V, Gardner R, et al.Electric field and thermal analysis of 132 kV ceramic oil-filled cable sealing ends[J]. IEEE Transactions on Power Delivery, 2020, 36(1): 311-319. [12] Yang Fan, Cheng Peng, Luo Hanwu, et al.3-D thermal analysis and contact resistance evaluation of power cable joint[J]. Applied Thermal Engineering, 2016, 93: 1183-1192. [13] 郭蕾, 李丽妮, 邢立勐, 等. 基于电-热场联合分析的EPR中压电缆终端异常热点仿真分析及优化[J]. 电力自动化设备, 2020, 40(7): 211-224. Guo Lei, Li Lini, Xing Limeng, et al.Simulation analysis and optimization based on electric-thermal field for abnormal distortion hot spots of EPR medium voltage cable terminal[J]. Electric Power Automation Equipment, 2020, 40(7): 211-224. [14] 周远翔, 张征辉, 张云霄, 等. 热-力联合老化对硅橡胶交联网络及力学和耐电特性的影响[J]. 电工技术学报, 2022, 37(17): 4474-4486. Zhou Yuanxiang, Zhang Zhenghui, Zhang Yunxiao, et al.The effect of combined thermal-mechanical aging on the cross-linking network and mechanical and electrical properties of silicone rubber[J]. Transactions of China Electrotechnical Society, 2022, 37(17): 4474-4486. [15] 刘昌, 惠宝军, 傅明利, 等. 机械应力对硅橡胶高压电缆附件运行可靠性的影响[J]. 高电压技术, 2018, 44(2): 518-526. Liu Chang, Hui Baojun, Fu Mingli, et al.Influence of mechanical stress on the operation reliability of silicone rubber high voltage cable accessories[J]. High Voltage Engineering, 2018, 44(2): 518-526. [16] 王霞, 余栋, 段胜杰, 等. 高压电缆附件设计环节中几个关键问题探讨[J]. 高电压技术, 2018, 44(8): 2710-2716. Wang Xia, Yu Dong, Duan Shengjie, et al.Dealing with some key design problems in HV cable accessory[J]. High Voltage Engineering, 2018, 44(8): 2710-2716. [17] 梁振, 彭杰, 胡军. 基于接触电阻模型的电缆接头复合材料界面温度及应力分布仿真研究[J]. 高压电器, 2021, 57(12): 147-155. Liang Zhen, Peng Jie, Hu Jun.Simulation study on interface temperature and stress distribution of cable joints based on contact resistance model[J]. High Voltage Apparatus, 2021, 57(12): 147-155. [18] 贾志东, 张雨津, 范伟男, 等. 10kV XLPE电缆冷缩中间接头界面压力计算分析[J]. 高电压技术, 2017, 43(2): 661-665. Jia Zhidong, Zhang Yujin, Fan Weinan, et al.Analysis of the interface pressure of cold shrinkable joint of 10 kV XLPE cable[J]. High Voltage Engineering, 2017, 43(2): 661-665. [19] 谢强, 王晓游, 傅明利, 等. 高压电缆接头过盈配合及硅橡胶附件力学性能计算[J]. 高电压技术, 2018, 44(2): 498-506. Xie Qiang, Wang Xiaoyou, Fu Mingli, et al.Interference fit and mechanical property computation of silicone rubber accessory in HV cable joint[J]. High Voltage Engineering, 2018, 44(2): 498-506. [20] 杨鑫, 刘真, 梁振, 等. 电-热耦合作用下高压电缆接头运行中复合界面热应力分布的仿真计算[J]. 电机与控制学报, 2020, 24(10): 100-108. Yang Xin, Liu Zhen, Liang Zhen, et al.Simulation calculation of thermal stress distribution of composite interface in operation of high voltage cable joint under electro-thermal coupling[J]. Electric Machines and Control, 2020, 24(10): 100-108.
2024, Vol. 39 
