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

Simulation Study on Interface Temperature and Stress Distribution of Cable Joints Based on Contact Resistance Model

为研究接触电阻过大而导致的压接缺陷对电缆接头温度及应力分布的影响,文中基于等效电导率的接触电阻理论,采用有限元软件建立了220 kV高压电缆接头压接缺陷下的电磁-热-应力多物理场耦合仿真模型,研究了电缆接头压接缺陷工况下预制件内硅橡胶绝缘/高压半导电复合材料界面温度和热应力特性的变化规律,并对不同负荷电流I和接触系数k下的温度、应力数据进行多元函数拟合,得到相应的计算方法。结果表明:高压电缆接头存在压接缺陷(如接触系数k=6)工况下,其复合材料界面热应力畸变了4.32倍,热应力的二次畸变程度大于温度的二次畸变程度;复合材料界面热应力分布的二次畸变是导致高压半导电管端头部位发生绝缘击穿故障的重要起因;压接缺陷下接头复合材料界面温度及应力可由拟合函数或图解法进行联合求解。

For studying the influence of crimping defects due to excessive contact resistance on the temperature and stress distribution of cable joints,in this paper,the electromagnetic-thermal-stress multi-physics coupling simulation model of 220 kV high voltage voltage joint under crimping defects is set up in accordance with contact resistance theory based on conductivity and by the use of finite element software.The variation of interface temperature and thermal stress characteristic of silicon rubber insulation in the prefabricated part/high voltage semiconducting composite material under the cable joint crimping defect is studied,the temperature and stress data under different load currents I and contact coefficient k are fitted with multiple functions so to obtain the corresponding calculation methods.The results show that,in case of crimping defect of high-voltage cable joints(for example,contact coefficient k=6),the thermal stress on the interface of the composite material is distorted by 4.32 times and the degree of secondary distortion of thermal stress is greater than that of temperature.The secondary distortion of the interface thermal stress distribution of composite material is an important cause of the insulation breakdown failure at the end of the high-voltage semiconducting tube.The interface temperature and stress of the composite material of the joint under the crimping defect can be jointly solved by the fitting function or the graphic method.