交联聚乙烯绝缘电缆中多树枝状缺陷联合劣化及相互影响机制分析  

Analysis of Joint Deterioration and Interaction Mechanism of Multiple Dendritic Defects in XLPE Insulated Cables

作　　者：姜茜 欧阳希 周湶[1] 李勇 罗振辉 陈明浩 JIANG Qian;OUYANG Xi;ZHOU Quan;LI Yong;LUO Zhenhui;CHEN Minghao(State Key Laboratory of Power Transmission Equipment&System Security and New Technology(Chongqing University),Shapingba District,Chongqing 400044,China)

机构地区：[1]输配电装备及系统安全与新技术国家重点实验室(重庆大学),重庆市沙坪坝区400044

出　　处：《中国电机工程学报》2021年第19期6806-6815,共10页Proceedings of the CSEE

基　　金：高等学校学科创新引智计划资助(BP0820005);国网湖南省电力公司科技项目(5216A517000Z)。

摘　　要：在实际运行环境中,湿度与过电压分别作为电缆绝缘中水树枝、电树枝缺陷引发及生长的关键性诱导因素,却因季节性波动变化与非连续作用的特点,导致水树、电树以协同生长方式加速绝缘劣化,研究树枝状缺陷联合劣化及其相互影响规律对提高电缆在复杂恶劣条件下绝缘寿命及运行可靠性具有学术价值。该文搭建水树-电树联合老化实验平台,开展水树-电树相互转化与协同发展试验,获取多树枝状缺陷的形貌特征、微观结构及电气性能参量,并分析出多树枝状缺陷联合劣化机制。研究发现:当电树生长过程中引入水树时,湿润水树可阻碍电树持续生长,并抑制内部局部放电;而干燥水树会加速电树的劣化;同时,历史性电树的存在会加速水树的生长,且在一定区域范围内,对水树的促进作用随电树的劣化程度递增。分析认为,湿润水树缺陷区的介电驰豫及枝状导电通道的分压作用是局部强电场削弱的原因,并且水分子对高能粒子的捕捉、约束作用也是导致电树生长得以抑制的原因;而干燥水树空腔结构及导电粒子的沉积为电树生长提供了供氧通道和高能粒子的运输通道;历史性电树生长时高温、光辐射等因素导致外围区域分子链断裂及无定形区的增加,会诱发亲水微通道并加速离子扩散,进而加速水树生长。In the actual operating environment, cable, humidity and overvoltage are the key inducing factors for the initiation and growth of water tree branches and electric tree branches. But due to seasonal fluctuations and discontinuous function characteristic, water tree and electrical tree both accelerated insulation degradation in coordinated growth. Therefore, studying the joint degradation of dendritic defects and their mutual influence has outstanding academic significance for improving the insulation life and operating reliability of cables under complex and severe conditions. In this paper, a water tree-electric tree joint aging experiment platform was built, and water tree-electric tree mutual conversion and collaborative development experiments were carried out, and the morphological characteristics, microstructure, and electrical performance parameters of multiple dendritic defects were obtained. The joint degradation mechanism of multiple dendritic defects was analyzed. The study found that when water tree is introduced during the growth of the electric tree, the wet water tree can hinder the continuous growth of the electric tree and inhibit the internal partial discharge. The dry water tree will accelerate the deterioration of the electric tree;at the same time, the existence of historical electric trees will accelerate the growth of water trees, and in a certain area, the promotion of water trees increases with the degree of deterioration of electric trees. The analysis believes that the dielectric relaxation of the wet water tree area and the partial pressure effect of the branch-shaped conductive channel are the reasons for the weakening of the local strong electric field, and the trapping and confinement of high-energy particles by water molecules is also the reason why the growth of the electric tree is inhibited. The dry water tree cavity structure and the deposition of conductive particles provide an oxygen supply channel and a high-energy particle transport channel for the growth of the electric tr

关 键 词：XLPE绝缘电缆 水树枝 电树枝 协同发展 相互影响 

分 类 号：TM215[一般工业技术—材料科学与工程]