Research on surface charge accumulation characteristics of post-composite insulators in polluted environments

Post insulators are commonly used in DC converter stations. Studying their contamination accumulation characteristics is crucial for reducing pollution flashover accidents and ensuring power systems’ safe and stable operation. This paper takes the FZSMW-75/8-Z post-composite insulator as the research object. Natural contamination accumulation tests are carried out under DC voltage. Group sampling of contamination accumulation on the upper and lower surfaces of insulator umbrella skirts resulted in a greater accumulation of dirt on the lower surface of the insulator skirt than on the upper surface. Based on the results of natural contamination accumulation tests, an FZSMW-75/8-Z insulator model is developed using COMSOL multiphysics simulation software. The simulation results are basically consistent with the natural contamination accumulation test results, verifying the rationality of the simulation model. Subsequently, aiming at the phenomenon of surface conductivity differences and surface charge accumulation caused by uneven contamination on the insulator surface, the surface charge accumulation situation is characterized by changes in surface charge density distribution. Analysis is carried out on how wind speed, the diameter of contaminating particles, and the inclination of wind direction impact the distribution of surface charge density on post-composite insulators. The results show that when the wind direction is fixed, the insulator’s surface charge density has a positive association with the wind velocity, and it first declines and then ascends as the diameter of the contaminated particles enlarges. When the wind direction changes, the surface charge density of the insulator slowly rises with the increase in airflow inclination.