Fractal characteristics of single PD pulse in electrical tree

A concept of sub-fractal dimension was put forward to describe the property of single PD pulse in an electrical tree which started from the needle tip and propagated along the tree channels. Our experiments on the light emission of single pulses showed that a single PD tended to have more branches in a bushlike tree with a larger base-fractal dimension than in a tree-like tree with a smaller base-fractal dimension. This agreed with the general consideration that larger sub-fractal structure should be formed in a framework with a larger base-fractal dimension. Further studies were carried out on the relation between the sub-fractal and the base-fractal dimensions by computer simulation. And we suggested that the tree growth rate was related to the difference between these two fractal dimensions