摘要
为了揭示直流电场下交联聚乙烯(XLPE)电力电缆中水树生长特性与直流电场极性的关系,进行了XLPE样本正/负极性直流电场下加速水树老化实验,分析了不同极性直流电场下XLPE/溶液界面结构对离子、水分向XLPE材料中迁移过程的影响,并进行了不同极性直流电场下水树区域的仿真分析,提出了直流电场极性影响水树生长特性的一种可能解释。研究结果表明:水树在负极性直流电场下比正极性直流电场下更长、老化更严重;在负极性直流电场下由于迁移至XLPE样本表面的氯离子存在特性吸附现象,界面结构中没有水偶极层阻碍氯离子进入XLPE材料中,所以迁移进入XLPE材料的离子、水分含量比正极性直流电场下更大;负极性直流电场下水树区域中有较多的离子、水分,使水树前端电场强度更大,有利于水树生长。因此基于XLPE/溶液界面结构的双电层理论分析,水树生长存在负极性直流电场下比正极性直流电场下长度更长、老化更为严重的现象。
To reveal the relationship of water tree propagation characteristics and DC electric field in XLPE power cables, accelerated water tree aging experiments of XLPE samples were performed under positive/negative DC electric field, and the influences of the XLPE/solution interface structure under different polarities DC electric field on the migration of ions and water molecules into XLPE material were investigated. Moreover, the electric field distribution of water tree regions under different polarities DC electric field was analyzed, and a possible mechanism was presented to explain how polari- ties of DC electric field affected water tree propagation. The results show water trees under negative DC electric field are significantly longer than those under positive DC electric field. Because of the characteristic adsorption of chloride ions on the XLPE material＇s surface under negative DC electric field, there is no water dipole layer of the interface to impede chloride ions migration. Therefore, the numbers of ions and water molecules in XLPE samples are greater, which lead to greater electric field strength at water tree tips and serious water treeing aging under negative DC electric field. Conse- quently, based on the electrical double-layer theory of the XLPE/solution interface, water trees under negative DC electric field propagate longer and more seriously than those under positive DC electric field.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2017年第11期3543-3550,共8页
High Voltage Engineering
基金
国家自然科学基金(51477106)~~
关键词
交联聚乙烯
直流电场
水树
离子
双电层
特性吸附
XLPE
DC electric field
water treeing
ions
electrical double layer
characteristic adsorption
