Self-consistent modeling of electrical tree propagation and PD activity

The self-consistent model of electrical tree propagation and partial discharge (PD) activity within growing tree channels is presented. The local electric field and the damage accumulation in the dielectric material surrounding the channels govern the tree growth. The damage increment is proportional to the energy release in the channels due to PD. The electric field distribution is determined by the charge deposition within the tree structure and the electrode geometry. The charge distribution changes within the channels during PD. PD starts when the electric field along the channels exceeds threshold inception value and stops when the field falls below the threshold quenching value. The numerical three-dimensional realization of the model has been used for simulation of electrical treeing with sinusoidal and triangular voltages in a needle-plane geometry. The spatial-temporal dynamics of the tree growth and phase-resolved characteristics of the PD have been studied for various magnitudes of the applied voltage. The simulation results have been compared with experimental data given in the literature.