Analysis of Electrical Tree Growth and Partial Discharge Stagnation in Epoxy Resin

The aging of electrical branch tree is an important cause for the degradation of the insulation performance of cable accessories. There are many studies on the electrical tree of epoxy modified materials, but there are few reports on the phenomenon of partial discharge (PD) stagnation of epoxy resin electrical tree. In this paper, an “integrated” epoxy resin needle-board model is made to produce electric tree. The effect of radius of curvature of the needle tips on electric tree is studied, include tree initial voltage, tree growth morphology, tree growth rate and partial discharge intermittent phenomena of electric tree. A set of experimental platform was built, and the detection sensitivity of partial discharge can reach 0.1pC. The test results show that: the larger the radius of curvature of the needle tip of the steel needle, the higher the tree initial voltage, and the higher the probability that it will develop into a vine-shaped electrical tree. The smaller the radius of curvature of the needle tip of the steel needle, the lower the tree initial voltage, and the greater the probability that it will develop into a branch-like electrical tree. The vine-shaped electrical tree has a partial discharge “stay period”, about ten minutes, while the branch-shaped electrical tree does not have a more obvious discharge stagnation phenomenon.