Effects of Adhesive Properties of Fine Particles on Surface Discharge of Outdoor Insulators in Fog-haze Conditions

With the acceleration of urbanization and rapid development of industry in China, the frequent appearance of fog-haze weather is becoming one of hazard conditions to affect the insulation reliability of outdoor insulators in power system. Due to the electric field induced by the operating voltage, the high electrostatic forces associated with the particle gravity will adsorb the surrounded floating particles onto the insulator surfaces, which can enhance the probability of surface discharges, even flashover. Therefore, the adhesive properties of these particles and their effects on surface discharges of outdoor insulators are essential to the safe operation of power system, which needs investigation from both theoretical and engineering viewpoints. An artificial contamination system was established to include the test power supply, artificial fog-haze chamber and data acquisition system. The fog-haze condition was simulated by the simultaneous wind-injection of saline fog and fine particles. The fog was generated by an ultrasonic vibration salt fog generator filled with saline water solution at different humidity and contamination levels. The fine particles were prepared conductive and non-conductive particles at different components. The quantitative analysis of adhesive particles and related discharges on the insulator surface were conducted in relation to the fog-haze parameters. The results obtained show that with the duration of fog-haze condition, the fine particles can result in the rapid increase of the equivalent salt deposit density (ESDD), and the ESDD on the top shed surface is larger than that on the bottom surface. The dissolvable electrolyte of fine particles can promote the contamination level. The contamination can cause the obvious decrease in the flashover voltage. The obtained results are helpful to understand the adhesive properties of fine particles and their effects on discharges of outdoor insulators in fog-haze conditions, which can enhance the operating reliability of outdoor insulators in power system.