基于微逾渗理论的电树枝引发和生长特性  

Initiation and Growth Characteristics of Electric Tree Based on Micro-percolation Theory

作　　者：李长云 王伟 王翰林 LI Changyun;WANG Wei;WANG Hanlin(College of Electrical Engineering and Automation,Shandong University of Science and Technology,Qingdao 266590,Shandong Province,China)

机构地区：[1]山东科技大学电气与自动化工程学院,山东省青岛市266590

出　　处：《中国电机工程学报》2021年第13期4720-4730,共11页Proceedings of the CSEE

基　　金：山东省重点研发计划(2019GGX102049)。

摘　　要：为研究绝缘介质内电树枝的引发与生长机理,该文提出微逾渗理论,进而建立电树枝的微逾渗模型,并利用环氧树脂CY1311的数值模拟与实测结果进行了有效性验证。数值模拟结果显示,微逾渗模型针对环氧树脂CY1311在7、10和15kV下的电树枝仿真图像与实验结果非常贴近,且7、10kV时数值模拟结果的分形维数与实验结果间的最大误差仅为5.8%。结果表明,在工频电压作用下,由针尖注入的电子增加了微区域的键逾渗概率,以及热电子对聚合物分子链的撞击,二者共同引发电树枝,并形成绝缘失效区;而邻近微区域中高能电子的冲击可进一步确定电树枝的生长方向。进一步地,外加电压与温度的升高均会增大微逾渗概率。所得结果有助于从微观层面理解电树枝的引发及生长过程,为探究电树枝的抑制措施提供参考。To study the initiation and growth mechanism of electrical tree in dielectrics, the micro-percolation theory was proposed in this paper. Then the micro-percolation model of the electric tree was established, and its validity of the proposed model was verified through the numerical simulation method compared to experimental results of epoxy resin CY1311. Numerical simulation results show that the simulation images of electric trees of the micro-percolation model for epoxy CY1311 at 7, 10 and 15 kV are very close to those obtained experimentally, and the maximum fractal dimension error between the numerical simulation results and the experimental results at 7 and 10 kV is only 5.8%. Under the action of alternative voltage with power frequency, the electrons injected into the dielectrics by the needle tip increase the probability of bond percolation in the micro-area, and the ramming of the hot electrons into the polymer molecular chain, the combination of the above two causes the electric tree initiation, and hence, insulation ineffective region will be formed. The impact of high-energy electrons in the adjacent micro-area can further determine the direction of the growth of the electric tree. Furthermore, the probability of micro-percolation is increased with the increase of the voltage and temperature. The obtained results in this paper are helpful to understand the initiation and growth process of electric trees from the microscopic level, meanwhile, it can provide reference for exploring the inhibition measures of electric trees within polymers.

关 键 词：电树枝 微逾渗理论 键逾渗 逾渗阈值 绝缘失效区 

分 类 号：TM85[电气工程—高电压与绝缘技术]