Influence of Diameter on the Contamination Accumulation Characteristics of Composite Insulators

In recent years, the use of composite station insulators has increased significantly. Field experience shows that the pollution accumulation on the surface of these insulators with larger diameters is less than that of composite line insulators with smaller diameters. The less pollution accumulation is beneficial for increasing pollution flashover voltage and improving long-term performances of the insulators. But at present, the experience in the influence of diameter on the pollution accumulation is only based on some measurement results, and its mechanism has not been analyzed in depth. In this paper, the three-dimensional CFD models of composite insulators with different diameters were built. The air flow field around the composite insulator was simulated by Fluent software. The collision rate between pollution particles and insulator surface was calculated. The simulation results show that the larger the insulator diameter is, the smoother the air flow around the insulator is, and the smaller the collision rate becomes. This can explain the less pollution accumulation of composite station insulators observed in the field.