The Influence of corona on the lightninig surge propagation along transmission lines

Corona is the partial discharge that occurs around the wires and edges in inhomogeneous electric field. Minimum intensity of the electric field for the impact ionization of the gas is around 2.6 MV/m in dry air. In power systems, the corona is the unwanted effect caused by overvoltages. In this study the propagation of the overvoltage wave due to negative lightning along the transmission line is numerically simulated. The effect of the corona is modelled by the drift-diffusion-reaction equations for the electrons, the positive and the negative ions.