Particle simulation of streamer discharges on DC transmission conductors with the presence of multiple raindrops

Streamer discharges on conductors in the presence of multiple raindrops are investigated through particle-in-cell simulations with Monte Carlo collisions included. Three discharge models are proposed, in which both the surface raindrops and space raindrops have been considered. The effects of the distance of raindrops as well as the horizontal and vertical distributions of raindrops upon the discharge characteristics are presented. The evolution of streamer discharges including the associated electric fields, electron densities, discharge currents, and electron energy probability functions is demonstrated. It is shown that the reduced distances of raindrops induce stronger discharges characterized by advanced discharge time, enhanced electric field strength, and increased plasma density. With an increasing number of space raindrops, the electron density and electric field of streamer discharges are promoted significantly. Our results provide fundamental insights into the discharge behaviors with multiple raindrops and offer guidance for the protection of high voltage direct current transmission systems in rainy weather.