有限元法分析交联聚乙烯电缆水树生长机理  

Mechanism of Water Tree Growth in XLPE Cables Based on Finite Element Method

作　　者：陶文彪[1] 马振国[1] 宋述勇 周凯[2] 黄明[2] 杨明亮[2] 

机构地区：[1]国网山西省电力公司电力科学研究院,太原030001 [2]四川大学电气信息学院,成都610065

出　　处：《绝缘材料》2016年第12期70-75,共6页Insulating Materials

基　　金：国家自然科学基金资助项目(51477106)

摘　　要：为了研究交联聚乙烯(XLPE)电缆中水树的生长机理,采用水针电极、高频高压的方法对XLPE薄片试样进行加速水树老化实验,通过显微镜观察经硅油加热处理前后的水树形态,构建有限元仿真模型,分析水树生长与电-机械应力的关系,并建立了水树生长的数学模型。结果表明:电-机械应力是导致水树生长的主要原因。在交变电场的作用下,环境中的水分在电缆绝缘中的杂质或缺陷处聚集,形成一系列充水微孔,并对其周围XLPE材料形成交变的Maxwell应力,导致XLPE分子链因应力疲劳而发生断裂,疲劳断裂的累积导致微孔体积增大、数量增多,这些微孔通过水树通道相连形成树枝状的水树形态。To study the mechanism of water tree growth in the cross-linked polyethylene （XLPE） cables, the XLPE slice samples were conducted accelerated water tree ageing test by liquid needle electrode and high-frequency high-pressure method, and the morphology of water trees before and after heating in silicone oil were observed by microscope. The relationship between water tree growth and electrical-mechanical stress was studied by finite element simulation model, and the water tree growth mathematical model was set up. The results show that the electrical-mechanical stress is the main cause of water tree growth. The moisture in environment gather at the impurities or defects of cable insulation under the action of alternating electric field, then the voids with water are formed. The alternating Maxwell stress is formed surrounding the water filled voids in XLPE materials, which causes the fracture of XLPE molecular chain because of stress fatigue. The accumulation of fatigue fracture results in the increase of volume and number of micro voids. The micro voids are connected by water tree channels, and the morphology of water tree is formed.

关 键 词：水树 XLPE电缆 有限元仿真 电-机械应力 屈服强度 

分 类 号：TM215[一般工业技术—材料科学与工程] TM247[电气工程—电工理论与新技术]