The Preparation Of Super-hydrophobic Coating And The Research On Its Icing Characteristics

In the power transmission system,icing is widespread phenomenon,which can cause bounce and rupture of transmission line and even lead to the fall of iron tower.With icing,the external insulation characteristics are always deteriorated to the extent that the flashovers of insulators can easily occur,which means the safety and stability of power transmission system are strongly chanllenged by icing.Notwithstanding the fact that super-hydrophobic coatings like RTV are widely used in power transmission system,they,with their contact angler not bigger than 110o,can't prevent icing at all,therefore the AC flashover voltage of insulators can't be increased when icing occurs.In order to prevent icing accendents and to decrease flashovers in icing,it is necessary to study and develop super-hydrophobic coating,on which the contact angle of water is bigger than 150o so that the waterdrops easily roll and fall from the surface of coating.On the surface of insulators painted with superhydrophobic coating,the water rolls and falls,which means that the waterdrops are scarecely captured,so icing can hardly happen.From this point of view,super-dydrophobic coating is a good method to prevent icing accidents and AC flashover of insultors.Based on lotus effect,the technics of preparing the super-hydrophobic coating is studied and its hydrophobicity properties analyzed.One glass-plate with this super-hydrophobic coating,one with RTV coating,and one without any coating are put together in the artificial climate chamber for icing test.Their surface ice morphology,their icing weight,their leakage current's frequency spectrum and their AC flashover voltage are tested,compared and studied.In order to know the anti-icing effects of this super-hydrophobic coating when used for isulators,3 insulators with this super-hydrophobic coating,3 with RTV coating and 3 without any coating are put in artificial climate chamber for icing test and based on the test results,the methods of developing the superhydrophobic coating and the auxiliary methods which can make anti-icing of this super-hydrophobic coating more effective are studied.The following conclusions are made based on test results:1) Micro-nano roughness structure is found on the super-hydrophobic coating,which leads to lotus effect and super-hydrophobicity.Only 6.6% of this surface is in contact with waterdrop on it and 93.4% with air; 2) The super-hydrophobic coating can evidently delay the icing process on glass-plate samples and insulators,and due to its super-hydrophobicity,the larger the inclination angle of the glass-plate sample with super-hydrophobic coating is,the less the weight of ice on it;3) Because the super-hydrophobic coating inhibits the forming of continuous ice film and on the surface of super-hydrophobic coating are only separated ice particles,the leaking current of the glass-plate sample with super-hydrophobic coating is much smaller than that of glass-plate sample with RTV coating and without any coating and the number of photons of the sample with super-hydrophobic coating discovered by ultraviolet imaging spectrograph is much less than that of sample with RTV coating and without coating;4) It is found that the flashover voltage of the sample with super-hydrophobic coating after icing is much higher thant that of the sample with RTV coating and without coating;5) It is very important for the safety of power transmission system to increase the inhibition time of super-hydrophobic coating against icing by replacing nano-particles of the same size with composite particles in making the coating or by developing auxiliary anti-icing measures.