热老化对Nomex绝缘纸表面电荷积聚消散特性的影响研究  

Effect of Thermal Aging on Surface Charge Accumulation and Dissipation of Nomex Paper

作　　者：李奕萱 高波[1] 李晓楠 杨雁[1] 郁郁 吴广宁[1] LI Yixuan;GAO Bo;LI Xiaonan;YANG Yan;YU Yu;WU Guangning(School of Electrical Engineering,Southwest Jiaotong University,Chengdu 610031,Sichuan Province,China)

机构地区：[1]西南交通大学电气工程学院,四川省成都市610031

出　　处：《中国电机工程学报》2020年第17期5707-5716,共10页Proceedings of the CSEE

基　　金：国家重点研究计划项目(2017YFB0902704)。

摘　　要：为研究变压器用Nomex绝缘纸在热老化过程中电荷的积聚消散特性,在实验室搭建加速热老化实验系统,制备试样,采用针-板电极向不同老化周期绝缘纸表面充电,测量电荷消散过程中绝缘纸表面电位分布情况,根据测得的表面电位衰减曲线计算得到不同老化周期绝缘纸表面陷阱分布特性。研究结果表明,施加电压后绝缘纸表面电荷呈钟形分布,消散过程中可以保持形貌;绝缘纸中电荷存在向绝缘纸内部消散和沿绝缘纸表面消散两种方式;随着老化程度的增加,绝缘纸表面积累的电荷量呈先减小后增加的趋势;未老化的绝缘纸以沿面消散为主,老化后绝缘纸表面电荷消散速度随老化周期而增加,但正电荷与负电荷消散速度增加的原因不同。研究结果为深入理解变压器高温运行过程中油纸绝缘系统电荷输运特性提供理论依据。In order to understand the evolution of charge accumulation and dissipation characteristics of Nomex paper during thermal aging progress,an experiment system of accelerated thermal aging was designed and the samples were prepared.The samples in different aging circles were charged by the needle plate model and then the surface charge decay progress was measured.The trap distribution of Nomex paper was calculated according to the surface potential attenuation curve.The results show that the initial surface potential distribution of insulation paper remains bell shaped during its decay.The volume conductivity and the surface conductivity contribute to the charge decay.The total amount of accumulated charge tends to decrease at first and then increase with the aging of insulation paper.In addition,the conduction through the surface of the unaged paper is the main reason for charge decay,the dissipation rate of positive charge and negative charge increase with the aging time for different reasons.The theoretical support was provided to understand the influence of thermal aging on charge transport characteristics of oil-paper insulation.

关 键 词：NOMEX纸 热老化 电荷积聚 电荷消散 陷阱分布 

分 类 号：TM855[电气工程—高电压与绝缘技术]