Numerical Simulation Study on the Influence of Temperature and Humidity on Streamer Discharge in Rod-Plane Air Gap

Distribution lines in mountainous forest regions are susceptible to high temperatures and humidity, resulting in a significant decline in their insulation performance. This frequently leads to air gap breakdowns, which have been the cause of numerous wildfire incidents. In this study, the collision reaction between particles is comprehensively considered from the microscopic point of view. The rod-plate discharge model based on the hydrodynamic is used to explore the influence of environmental temperature and humidity changes on the generation, development, and evolution of discharge plasma particles and their effects on electron density, electric field intensity, streamer propagation rate, and streamer radius. The simulation results indicate that within the temperature range of 300-400 K and the relative humidity range of 20%-60%, there is a notable increase in streamer electron density and electric field intensity. However, at higher temperature and humidity levels, this increase results in a slight decrease in streamer electron density and electric field intensity. The streamer propagation velocity follows a three-stage pattern of "fast-slow-fast", with a significant acceleration due to the increase in temperature and humidity. With rising temperatures, the streamer radius also expands. Similarly, within the relative humidity range of 20%-60%, the streamer radius increases as humidity levels rise, while excessive humidity reduces the channel's radius. The simulation results presented in this article offer valuable insights for assessing the distribution air gap discharges and preventing resultant wildfires.