Study On Preparation And Properties Of Condensation And Anti-Pollution Flashover Of A Methyl Silicone Resin Superhydrophobic Coating

Under the influence of atmospheric pollution,pollution flashover of insulators seriously affects the operation safety of electrical power system.Superhydrophobic coating has the ability of self-cleaning,and the insulators coated with superhydrophobic coating are effective in improving the anti-pollution performance and pollution flashover voltage of insulators.However,the micro-nano structure of superhydrophobic coating is easy to wear,which hinders the engineering application of superhydrophobic coating.In this paper,a methyl silicone resin superhydrophobic coating was developed.The dielectric properties,surface flashover voltage under power frequency,condensation characteristics and anti-pollution flashover of methyl silicone resin superhydrophobic coating were investigated.The main contents of the paper are as follows:(1)A novel methyl silicone resin superhydrophobic coating was fabricated and the abrasion resistance of the coating was studied.To solve the issue of low abrasion resistance,methyl silicone resin and nano silica were selected to prepare superhydrophobic composite coating,and the effect of methyl silicone resin on improving the stability of dual micro-nano structure was qualitatively analyzed.The methyl silicone resin superhydrophobic coating was prepared by air spraying method.The hydrophobicity,surface hardness,adhesion and abrasion resistance of the superhydrophobic coating were studied.Results show that methyl silicone resin superhydrophobic coating has a good abrasion resistance.(2)The dielectric properties and surface flashover characteristics under power frequency of methyl silicone resin superhydrophobic coating were studied.Relative dielectric constant,dielectric loss factor and volume resistivity of the superhydrophobic coating under different frequencies were measured and analyzed.The power frequency flashover voltage and leakage current of the glass slide coated with methyl silicone resin superhydrophobic coating under dry and wet conditions were investigated.The influence of the trap depth of coating and electric field distribution of droplet on flashover voltage under dry and wet conditions were analyzed,respectively.Results show that methyl silicone resin superhydrophobic coating has a good insulation performance and increases the dry and wet flashover voltage under power frequency.(3)The condensation characteristics of methyl silicone resin superhydrophobic coating under a tangential AC electric field were studied.The condensation process of the superhydrophobic surface under a tangential AC electric field was observed,and the surface coverage,diameter and number of droplets were measured and analyzed.The electric-field-induced jumping of droplets under a tangential AC electric field was observed with a high-speed camera,and the relationship between the instantaneous direction of AC electric field and droplet jumping direction was analyzed.Results show that droplets are easy to jump out of the superhydrophobic surface under a tangential AC electric field,and the surface coverage of condensed droplets significantly reduces,which helps to improve the anti-pollution flashover performance of insulators.(4)The anti-pollution flashover performances of methyl silicone resin superhydrophobic coating were studied.The deposition process of artificial contamination on insulator surface was observed.The influence of the surface wetting state of insulators on pollution flashover characteristics under power frequency was studied and analyzed.The microscopic morphology of contamination on superhydrophobic surface and the dynamic process of self-cleaning were studied.The self-cleaning mechanism of superhydrophobic coating,which trapped the contamination particles,was deeply analyzed.Results show that methyl silicone resin superhydrophobic coating significantly reduces the contamination and wetting degree of insulator surface,and increases the pollution flashover voltage of insulators with different contamination degrees.The polluted superhydrophobic surface,which losses hydrophobicity,has the ability of superhydrophobcity recovery.The above results indicate that the methyl silicone resin/silica superhydrophobic coating with favourable abrasion resistance and stability is prepared by improving the surface hardness and adhesion of coating.The coating has good insulating properties,and shows superior anti-pollution flashover performances in artificial contamination test.