Research On The Key Factors Impacting Insulator Hot Washing Cleaning Effect

Electricity is an indispensable energy in modern society,which closely related to people's daily life and industrial production,and also has the irreplaceable role of economic development.Guaranteeing the normal operation of electrical equipment is very important.With the rapid development of industry and agriculture,the external emission of various pollutants is also increasing,and the external insulation electrical equipment of power system is easy to be contaminated,which will affect the insulation performance,causing the pollution flashover accident,and bring great influence to the society,economy and people's life.Therefore,it has great significance for power equipment to be cleaned in time,the insulator is one of the most basic and widely used components in power system,it is more important to ensure its cleanliness.Theoretical research was carried out to analyze the adhesion force and removal mechanism of insulator contaminations.Numerical simulation was done by CFD software,analyzing the variation trend of the jet hitting force with parameters,such as the nozzle exit diameter,target distance,flushing angle and inlet pressure,the influence of subumbrella structure and splashing water on insulator hot washing was also be analyzed.Provided a reference for the insulator hot washing,to complete the cleaning work safely and efficiently.The main contents of this paper are as follows:1.The adhesion force is mainly composed of van der waals force and capillary force,and has been calculated by the simplified model:the adhesion force between contamination particles and the insulator surface is 2.2×10-5N the adhesion force between particles is 1.1×10-5N.The contamination particles had different removal mechanism under the action of hot washing,force analysis had been done of particles in hot washing,based on the adhesion force that calculated before,and it is considered that the contamination particles are more likely roll off from the surface of the insulator in pairs.2.The jet impact characteristics was analyzed by Fluent,and the hitting force function of three different nozzle diameters was obtained by Matlab fitting.It can be seen that the hitting force of jet increased with the increase of pressure,and decreased with the increase of the target distance,therefore,on the premise of ensuring safety,increasing the inlet pressure and shortening the target distance are effective way to improve the cleaning efficiency.Different flushing angle will result in the difference of cleaning effect near the axis of the jet,because the distribution of jet velocity,jet pressure and jet thickness are not uniform,and the flush angle of 20°?30° have a higher cleaning efficiency.The hitting force can be effectively improved with the increase of nozzle diameter,but will also lead to more water quantity and energy consumption,as water quantity and energy is less sensitive to the pressure,it is preferred to lifting pressure to obtain higher hitting force.3.Because of the structural characteristics of different subumbrella,there are some differences in the flow condition under different flushing angles,but the near wall velocity is consistent with the variation of pressure.With the large flushing angle,the kinetic energy of the jet was directly acting on the contaminations,and the vertical velocity component is large,the contaminations can be broken more effectively.The horizontal velocity component decreased with the increase of flushing angle,after the critical cleaning pressure was achieved,the small washing angle is selected to improve the cleaning efficiency.After comprehensive consideration of the flow characteristics,near wall velocity and effective cleaning area,the flush angle of 20° should be preferred to ensure a higher cleaning efficiency.4.The effect of splashing water on hot washing are in many ways,it can increasing the cleaning area and improving cleaning efficiency,but may also leads to higher insulator leakage current and cause flashover,affecting the safety of hot washing.Besides,splashing water will wetting contaminations before washing,changing their physical properties,the main reason of contaminations removal was changed from internal stress into the directly shear of water pressure.At the same time,splashing water caused the increase of relative humidity,which can increasing the adhesion force,but has little effect on the cleaning dynamic pressure.