Study on the transformation of electrical tree from water tree degradation in XLPE

During the experiments, peroxide cross-linked polyethylene is chosen as the experimental material, liquid needle electrode and high frequency accelerated aging method are used for water tree development, and real-time digital microscopic camera system is used for observation of water-tree-transformed electrical treeing. In this paper, the transformation of electrical trees from wetting and drying water tree samples with different electrodes (water needle electrode, steel needle electrode) is studied at different voltages (15kV, 20kV). Three experimental results are obtained. (1) The average electrical tree initiation time of non-deterioration samples is shortest, that of wetting water tree samples is longest, while that of drying water tree samples is the medium of the two mentioned above. (2) The electrical tree initiation rates of drying water tree samples is highest, that of wetting water tree samples is lowest, and that of non-deterioration samples is the medium of the two mentioned above. (3) When water needle electrode is used in the three kinds of samples, the electrical trees initiated are all branch-like. The different mechanisms of electrical treeing in the three kinds of samples are studied.