高寒车载柔性电缆终端放电通道延伸与击穿过程的研究

电力机车在高寒地区运行时,会出现车载电缆柔性终端炸裂故障。为了研究击穿过程并探究击穿机理,首先在实验室内通过搭建低温实验平台模拟还原了电缆终端低温运行的实际工况,进而实施了局部放电及低温耐压试验。试验结果表明,低温下电缆终端发生局部放电,并在耐压试验中发生击穿,与实际情况相符。通过解剖电缆终端发现,应力管内部有明显的放电通道,外半导体层边缘及应力管末端有大范围烧蚀痕迹,击穿点位于应力管末端。在此基础上本文建立了电缆终端的三维立体模型,并基于有限元仿真软件进行仿真分析计算,仿真结果表明电缆终端存在大范围烧蚀痕迹位置,电场畸变同样严重,与试验结果吻合。最后本文探讨了放电通道延伸与击穿过程。

Study on Extension and Breakdown of Discharge Channel in Flexible Cable Terminal in Electric Locomotive Operating in Alpine Region

During the operation of a locomotive in the alpine region,a fault of onboard flexible cable terminal crack may appear.In order to study the process and mechanism of breakdown,the actual working condition of the cable terminal at low temperature was simulated by the low temperature experiment platform built in the laboratory.Then the partial discharge test and the low temperature voltage withstand test were carried out.The results show that the occurence of partial discharge at the cable terminal at low temperature and the occurence of breakdown in the voltage withstand test,are consistent with the actual situation.By dissecting the cable terminal,it is found that the stress tube has clear discharge channels,and a wide range of ablation traces exist in the outer edge of the semiconductor layer and the end of the stress tube with the breakdown point located at the end of the stress tube.Based on the research above and the finite element analysis and simulation software,the three-dimensional model of the cable terminal was established.The simulation results show that the electric field distortion of the cable terminal where there are a wide range of ablation traces is the same as the experimental results.Finally,the process of discharge channel extension and breakdown was discussed.