Simulation of electrical tree growth in solid dielectrics containing voids of arbitrary shape

In this paper the electrical tree growth in solid insulating materials containing voids of arbitrary shape is modelled using von Neumann's cellular automata (CA). The model is based upon the assumption that the electric stress at the end of a conducting tip quite often approaches the dielectric strength of the material and that progressive breakdown may occur by electrical tree formation. Because of tree advancement, the potential distribution within the insulating material changes with time, and it is calculated at each time step. An algorithm, based on this model, for the simulation of electrical tree growth in solid dielectrics containing voids of arbitrary shape has been developed. Simulation results show that voids constitute a danger for solid insulation, because they act as sources of secondary electrical trees. An interaction mechanism between voids within a dielectric is proposed and discussed.