有限元法分析交联聚乙烯电缆水树生长机理

发布时间：2019-06-14 21:30

【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。
[Abstract]:In order to study the growth mechanism of water tree in crosslinked polyethylene (XLPE) cable, the aging experiment of XLPE sheet was carried out by means of water needle electrode and high frequency and high voltage. The morphology of water tree before and after heating with silicone oil was observed by microscope, the finite element simulation model was constructed, the relationship between water tree growth and electro-mechanical stress was analyzed, and the mathematical model of water tree growth was established. The results show that electro-mechanical stress is the main cause of water tree growth. Under the action of alternating electric field, the moisture in the environment accumulates at the impurities or defects in cable insulation, forming a series of water-filled micropores, and forming alternating Maxwell stress on the surrounding XLPE material, which leads to the fracture of XLPE molecular chain due to stress fatigue, and the accumulation of fatigue fracture leads to the increase of micropore volume and the increase in the number of micropores. These micropores are connected by water tree channels to form dendritic water tree morphology.
【作者单位】：国网山西省电力公司电力科学研究院;四川大学电气信息学院;
【基金】：国家自然科学基金资助项目(51477106)
【分类号】：TM247;TM75

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