Fractal dimensions analysis of branching streamers propagating in mineral oil

This article deals with the analysis of the fractal dimension of streamers propagating in mineral oil, under lightning impulse voltage, using the box counting method; the method and technique of calculation are described therein. In the considered experimental conditions, the average velocities of recorded streamers are of 2.4 km/s and 1.8 km/s for positive and negative streamers, respectively; these velocities correspond to the 2nd mode of streamers propagation. It is shown that the streamers present the fractal dimension D ; and the higher D is the bushier are the streamers (i.e. with high branch density). The positive streamers can have higher D than the negative ones, if they are bushier.