摘要
直流电场作用下绝缘聚合物老化演变的仿真研究,对促进计算高电压工程学的发展有重要的理论及工程价值。为此使用MATLAB自定义编程,在二维坐标中建立有限差分老化数值模型;用绝缘薄膜的老化寿命数据所拟合的小尺寸结构单元的通用参数,表征大尺寸绝缘样品的材料不均匀性;并基于化学反应速率理论,量化计算绝缘老化过程。通过仿真发现,绝缘聚合物内部的薄弱点率先发生微小劣化,导致局部电场畸变;增强的局部电场进一步加速局部区域的老化进程,引起劣化区域的扩大与延伸;最终当局部场强达到临界值时,绝缘内部发生快速的击穿过程,并形成贯穿上下电极的细丝状导电路径,在靠近极板时由于局部电场分散性而出现分形的失效结构。该研究提出的数值仿真模型可高效、直观地反映绝缘聚合物老化过程中,从随机性局部劣化演变到确定性宏观失效的物理规律,为深入理解绝缘老化失效提供了理论参考和依据。
The simulation of DC ageing evolution in insulating polymers is of an important significance in promoting the development of computational high voltage engineering(CHVE) both for theoretical understanding and practical application. We propose a numerical model of ageing with the finite difference grid in the two-dimension coordinate which is programmed by using MATLAB. The material inhomogeneity of large-size samples is characterized by generic features assigned to small-size elements based on fitting parameters obtained from life data of thin films. The quantitative simulations of ageing are carried out by using the chemical reaction rate theory to calculate theageing process. It was found that micro degradation occurs in weak spots at the early stage causing local electric field distortion. The local field enhancement further accelerates the local ageing process which leads to the growth and extension of degraded regions. Once the local field reaches the critical value, the final breakdown occurs to form a filamentary conducting path linking the two electrodes with a small volume of fractal structure due to the field divergence when approaching the electrode. The proposed simulation is efficient and visualized to reflect the physical pattern leading from stochastic micro degradation to deterministic macro failure in the ageing process of polymeric insulation, which provides theoretical reference and basis for in-depth understanding of ageing failure.
作者
左周
姚陈果
DISSADO L A
高岩峰
DODD S J
CHALASHKANOV N M
ZUO Zhou;YAO Chenguo;DISSADO L A;GAO Yanfeng;DODD S J;CHALASHKANOV N M(State Key Laboratory of Power Transmission Equipment&System Security and New Technology,Chongqing University,Chongqing 400030,China;Department of Engineering,University of Leicester,Leicester LE17RH,UK;State Grid Jibei Electric Power Co.Ltd.Research Institute,Beijing 100045,China;School of Engineering,University of Lincoln,Lincoln LN67TS,UK)
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2020年第3期832-842,共11页
High Voltage Engineering
基金
国家创新研究群体基金(51321063).
关键词
计算高电压工程学
化学反应速率理论
材料不均匀性
老化
击穿
绝缘聚合物
computational high voltage engineering
chemical rate theory
material inhomogeneity
ageing
breakdown
insulating polymers
