运行复合绝缘子伞裙的力学特性及分子动力学模拟研究

Study on mechanical characteristics and molecular dynamics simulation of composite insulator sheds in service

为更精细化评估伞裙的微观结构和材料组成等因素对绝缘子宏观性能的影响,本文结合分子动力学模拟方法对不同运行年限的交流复合绝缘子进行力学性能、热失重、傅里叶红外光谱等测试。结果表明:随着运行年限的增加,绝缘子从低压端到高压端的伞裙抗撕裂强度、拉伸强度、断裂伸长率整体呈下降的趋势;伞裙外层有机硅和SiO2的含量大幅下降,可造成宏观力学性能下降;在电-热环境下,伞裙的体积模量、杨氏模量和泊松比随温度的升高整体呈下降的趋势,随电场强度的升高整体呈波动性;绝缘子高压端的电场畸变最严重,力学性能最差。本文建立的复合绝缘子伞裙老化的多尺度模型,可为评估绝缘子老化状态提供参考。

In order to more finely evaluate the influence of factors such as the microstructure and material composition of the shed on the macroscopic performance of insulators,the mechanical properties,thermal weight loss,and Fourier infrared spectrum of AC composite insulators with different operating years were tested combined with the molecular dynamic simulation method in this paper.The results show that with the increase of operating years,the tear strength,tensile strength,and elongation at break of the insulator shed from low-voltage end to high-voltage end show a decreasing trend.The content of organic silicone and SiO2 in the outer layer of shed significantly decrease,which can cause a decrease in macroscopic mechanical properties.In the electro-thermal environment,the bulk modulus,Young′s modulus,and Poisson′s ratio of the shed decrease with the increase of temperature and fluctuate with the increase of electric field strength.The high-voltage end of insulator has the most severe electric field distortion and the worst mechanical properties.The multi-scale model of the composite insulator shed ageing established in this paper can provide a reference for evaluating the ageing state of insulator.