Surface Texture Design Of The Superhydrophobic Composite Insulator Sheds

Composite insulators are widely applied in power systems because of their excellent insulating properties and hydrophobic properties.However,the composite insulator sheds will be polluted by acid rain,haze,dust and industrial pollution,resulting in pollution flashover.Besides,insulators will also cause ice accretion during high humidity and cold weather,which can easily cause icing flashover and even cause serious accidents such as tower collapse.Therefore,the design of the superhydrophobic composite insulator sheds can increase the hydrophobicity of the surface,reduce the fouling,delay and improve icing accretion of the composite insulator,which is of great significance to reduce the fault of transmission line.With the help of the existing Young equation,Cassie equation and Wenzel equation,and the modified equations,the relationship between the advancing contact angles,receding contact angles,contact angle hysteresis,free energy change,adhesion work,the spreading coefficient and the apparent contact angles during the wetting process on the rough surface are analyzed.And then,the corresponding analytical relations are established.Furthermore,these relationships are extended to different texture surfaces to provide theoretical verification for the difference of hydrophobic properties of the actual texture surface.In this paper,two kinds of coatings were prepared on the surface of composite insulator sheds which are superhydrophobic flower-like PDES-MoO₃/CMF coating and superamphiphobic FOTS-SiO₂ coating respectively to change its hydrophobicity by forming random micro-nano texture.The surface morphology and chemical composition of the samples were characterized by means of scanning electron microscopy?SEM?and FTIR spectrum.Additionally,the contact angle and sliding angle were measured under different test conditions by contact angle measuring instrument to research the hydrophobicity,chemical durability,mechanical stability and self-cleaning properties of coatingsThe texture with different shapes,sizes,spacing and height were prepared on the sheds surface by laser engraving,and the relationship between the texture parameters and hydrophobicity were discussed respectively.At the same time,the changes of the contact angles and the rolling angles were used to analyze the variation law of the surface hydrophobicity of all kinds of texture with soaking time,pollution time,UV-irradiation time and the number of the mechanical wear.In addition,the motion state,time of movement and jumping height of droplets on the texture surface are obtained through high-speed camera to explore the motion law of the droplets on the texture surface,and it helps to find which surface structure is conducive to the rolling of droplet.The results show that both the superhydrophobic coating and the sheds surface texture formed by processing can greatly improve the hydrophobic properties of the surface of the composite insulator.Although the coating method can get better superhydrophobicity?contact angles>157°,sliding angle<5°?with great chemical stability and self-cleaning performance.However,the skirt samples via photolithography not only has good superhydrophobic,self-cleaning,anti-fouling,corrosion resistance and other properties,but its insulation and mechanical strength are also high,especially for rhombic texture surface.