Numerical Investigation on Collision of Pollution Particles on Outdoor Insulators

Abstract

Accumulation of pollution particles on outdoor insulators is the premise of pollution flashover accidents in power systems. In this paper, according to the actual operating polymer insulators, the wind velocity, the concentration of pollution particles, the diameter of pollution particles, and the hanging angle of insulator were considered to investigate the accumulation characteristic of pollution particles by using FLUENT software. The pressure nephogram of polymer insulator, the velocity vector of air flow field, movement trajectory of pollution particles, and collision rate were obtained. It is found that the pressure of the insulator surface on the windward side is bigger than that on the leeward side, and the pressure difference increases with increasing the wind velocity. As the increase in particle diameter, the collision rate between pollution particles and insulator surface shows the increasing tendency. When the diameter of pollution particles is small, the easier the particles follow the airflow to bypass the insulator surface without colliding with it. However, due to the influence of gravity force and inertia, the collision rate of pollution particles increases significantly with the increase in particle diameter. Under the strong wind velocity, the air swirls are generated on the leeward side of the insulator surface, causing the collision rate of the pollution particles increases slowly with the increase in the wind velocity. While the concentration of pollution particle increases, the collision number between insulator surface and pollution particles shows the increasing tendency at different wind velocity. When the particle diameter is in range of 1 to 8 μm, with increasing the hanging angle of “V”type insulator from 0° to 60°, the collision rate of pollution particles shows the increasing tendency. When the particle diameter is 9 to 50 μm, the collision rate of particles shows the increasing tendency when the insulator angle is lower than 30°, but shows the decreasing tendency from 30°to 60°. As the humidity increases, the water vapor in the air prevents the movement of pollution particles, resulting in a decrease in the collision rate. With increasing the pollution particles diameter, the influence of air humidity on the collision rate of pollution particles is gradually weakened.