Three-Dimensional Fractal Structure Analysis of Branch-Type Electrical Trees in XLPE Materials Based on XCT Technology

The phenomenon of the electrical tree, as a key cause of insulation performance degradation in cross-linked polyethylene (XLPE) cables, is of great significance for understanding and predicting insulation failure mechanisms via the exploration of its three-dimensional (3D) fractal structural characteristics. In this study, X-ray computed tomography (XCT) technology was used to reconstruct the 3D structure of electrical trees in XLPE insulation, and the fractal characteristics of the electrical trees were studied from two aspects: branch diameter and branch length. The distribution law of the diameter and length of each branch was explored by extracting the 3D skeleton structure of the electrical tree. The results show that the diameter and length of each branch of the electrical tree were found to follow lognormal distributions, with average values of 2 ~ 3 and 20 ~ 30 μm, respectively. These results yield a new experimental basis for the quantitative numerical analysis, growth characteristics, and mechanism research of electrical trees, helping to better evaluate the insulating properties and predict the insulation life of XLPE cables.