基于电-热-力场的10 kV电缆终端典型缺陷仿真研究

Simulation study on typical defects of 10 kV cable terminal based on electro-thermo-mechanical field

为了研究电缆终端硅橡胶/交联聚乙烯(SR/XLPE)复合界面典型缺陷对电场、温度场以及应力场分布的影响,采用COMSOL Multiphysics仿真软件建立了10 kV电缆终端仿真模型,对复合界面存在金属微粒、半导电微粒以及划痕缺陷时的电-热-力场分布情况进行仿真。结果表明:电缆终端复合界面存在金属微粒或半导电微粒时,界面缺陷区域的电场、温度场以及应力场存在不同程度的畸变,金属微粒对界面各物理场分布的影响更加明显。对于外半导电层截断处因交联聚乙烯划伤导致气隙缺陷的情况,发现界面气隙缺陷处电场发生畸变进而产生局部热点。界面涂覆硅脂对划痕处电场和温度场的畸变具有明显的改善作用,但划痕区域由于硅脂的填入导致应力分布不均匀,应力呈现两端高中间低的分布规律。

In order to study the influence of typical defects at the silicone rubber/cross-linked polyethylene(SR/XLPE)composite interface of cable terminal on the electric field, temperature field, and stress field distribution, a 10 kV cable termination simulation model was established by using COMSOL Multiphysics simulation software. The electric-thermalforce field distribution with metal particles, semiconducting particles, and scratch defects on the composite interface was simulated. The results show that the electric field, temperature field, and stress field on the interface defect area are distorted to different degrees when metal particles or semi-conductive particles exist on the composite interface of cable terminal, and the influence of metal particles on the physical field distribution at the interface is more obvious. For the air gap defect caused by the scratch of XLPE at the truncation of outer semiconductive layer, it is found that the electric field at the interface air gap defects is distorted and local hot spots are generated. The coating of silicone grease on the interface can obviously improve the distortion of electric field and temperature field at the scratch, but the stress distribution in the scratch area is not uniform due to the filling of silicone grease, and the stress is high at both ends and is low in the middle.