摘要
电树枝现象作为交联聚乙烯(XLPE)电缆绝缘性能退化的关键诱因,深入探究其三维分形结构特征对于理解绝缘失效机制具有重大意义。本文采用X射线计算机断层扫描(XCT)技术重建XLPE绝缘层内电树枝的三维结构,并从分形维数及分叉角度两个方面研究了电树枝的分形特征,建立了电树枝三维分形维数与二维分形维数之间的数量关系。同时,通过提取电树枝的三维骨架结构,探究了其各分支分叉角度的分布规律。结果表明:XLPE材料中枝状电树枝的三维分形维数与二维投影的分形维数之间满足线性关系;电树枝各分支的分叉角度服从正态分布,三维分形维数小于2的枝状电树枝的分叉角度均值约为60°,三维分形维数大于2的丛状电树枝的分叉角度略小,约为50°,且随着电树枝向地电极生长,各分支的分叉角度的平均值呈现先增大后减小的趋势。
The phenomenon of electrical tree is a key factor inducing the degradation of insulation performance in cross-linked polyethylene(XLPE)cables,an in-depth exploration of its three-dimensional fractal structural characteristics is of great significance for understanding the insulation failure mechanisms.In this paper,the three-dimensional structure of electrical trees inside XLPE insulation layer were reconstructed by using X-ray computed tomography(XCT)technology,and the fractal characteristics of electrical trees were studied from two aspects:fractal dimension and bifurcation angle.The quantitative relationship between the three-dimensional fractal dimension and two-dimensional fractal dimension of electrical tree was established.At the same time,by extracting the three-dimensional skeleton structure of electrical trees,the distribution pattern of bifurcation angles among their brunches was explored.The results show that there is a linear relationship between the three-dimensional fractal dimension and the fractal dimension of two-dimensional projection of the branch-type electrical trees in XLPE material.The bifurcation angles of each electrical tree branch follows a normal distribution.The average bifurcation angle of the branch-type electrical tree with a three-dimensional fractal dimension less than 2 is about 60°,while the average bifurcation angle of the bush-type electrical tree with a three-dimensional fractal dimension greater than 2 is slightly smaller,about 50°.As the electrical trees grow towards the ground electrode,the average value of the bifurcation angles of their branches first increases and then decreases.
作者
赵洋
薛强
刘青
郭甜
尚英强
马宪伟
ZHAO Yang;XUE Qiang;LIU Qing;GUO Tian;SHANG Yingqiang;MA Xianwei(State Grid Beijing Electric Power Company Cable Branch,Beijing 100031,China)
出处
《绝缘材料》
北大核心
2025年第9期109-117,共9页
Insulating Materials
基金
国家电网公司总部科技项目(5500-202211398A-2-0-ZN)。
关键词
电树枝
交联聚乙烯
分形结构
X射线计算机断层扫描技术
分叉角度
electrical tree
cross-linked polyethylene(XLPE)
fractal structure
X-ray computed tomography(XCT)technology
bifurcation angle
