Simulation on the development progress of positive glow corona discharge from ground wire of AC/DC transmission lines under thunderstorm condition

In thunderstorm weather, lightning induction appears on the surface of ground objects, and then the positive glow corona is initiated, which influences the selection of lighting targets by lighting leader. So, it has great research value for lightning protection of AC/DC transmission lines. Here, a two-dimensional model of positive glow corona is established in COMSOL Multiphysics. From the simulation results of its development progress, corona current, ion distribution, and migration are revealed. The positive ions are in a round symmetric distribution at the initial stage of migration, but when the ions move farther away, ions become an elongated oval distribution. Also, most of the ions move to the thundercloud in the end. The positive ions accumulate above the transmission line and form a positive background, which has confinement and attenuation to electronic beam. Therefore, the probability of the electron avalanche converted into flowing is reduced. Meanwhile, the positive background promotes the compound of ions and electrons. As a result, the initiation of upward leader is suppressed and so the selection of lighting targets by lighting leader is influenced.