Analysis Of Icing Mechanism Of Distribution Lines And Anti-icing Performance Of Hydrophobic Coating

In the power grid system,icing is a destructive natural disaster,which does great harm to the transmission and distribution lines and other equipment.At present,the current deicing technology and mechanical deicing method widely used in the system are difficult to achieve the maximum deicing potential due to the limitation of power and current in low voltage distribution lines.According to the principle that the hydrophobic surface has anti icing performance,the method of adding coating on the outside of the line is adopted to prevent the occurrence of ice cover disaster.The research improves the operation status of distribution lines affected by icing under extreme weather conditions,provides reliable technical support for the future anti icing scheme of power grid,and reduces the economic losses caused by extreme rain and snow weather.Based on the study of the mechanism of material surface hydrophobicity and deicing,the hydrophobic coating was constructed on the surface of aluminum wire,and its anti-icing performance and weather stability were tested.In order to test the icing performance of distribution lines,a simulation platform of icing environment was built.This test platform consists of an environment simulation test box and a control circuit.The test box equipped with semiconductor refrigeration plate chip,fan unit,cooling water pump,atomizing vibration humidifier and dripping rain device,which can simulate the low temperature rain environment with temperature of-20～0℃and relative humidity of more than 80%.Through the control of the circuit,it can simulate the icing of transmission line under various freezing rain conditions.The hydrophobic coating is based on epoxy resin coating and modified by adding polydimethylsiloxane（PDMS）or Si O₂.The coating can be formed on the metal surface by stirring and spraying.The surface contact angle of the epoxy coating containing PDMS is109.2°and the maximum contact angle of the epoxy coating containing PDMS and Si O₂is146.7°with excellent hydrophobicity.The coating has good bonding performance with aluminum alloy and is not easy to fall off,and it is easy to be coated on the surface of aluminum stranded wire structure.The hydrophobic coating has shown excellent anti icing performance in the line icing test conducted in the environmental simulation test box.Among them,the epoxy resin coating modified with PDMS and Si O₂ has the best hydrophobicity,which can push the freezing time of 10μm water drop on the surface of aluminum plate to 900 s at-10℃,and extend the freezing time of water drop to more than 1800 s at-5℃.In the low temperature rain test with relative humidity of 80～90%,ambient temperature of-15℃and dripping rate of 3000μL/min,the icing mass of the epoxy resin coating with PDMS and Si O₂ is 12.4%less than that of the original aluminum strand without coating.When the ambient temperature is-10℃and-5℃,the coating quality of hydrophobic outer layer can be reduced by 27.5%and 66.8%respectively.This shows that the ability of hydrophobic coating to slow down ice accumulation is more significant in the higher temperature range below freezing point.In addition,the hydrophobic coating can also change the icing morphology on the outside of the line,and increase the proportion of ice mass in the total icing by 4～6%.These icicles gathered under the line are easier to be removed by current heating or mechanical vibration.In the weathering test of the coating,the epoxy resin coating with PDMS has better hydrophobic stability,while the surface roughness of the epoxy coating with PDMS and Si O₂will be destroyed in the rain impact and high temperature aging tests.However,the contact angle of the coating can always be kept above 130°,which also has a certain hydrophobic stability and engineering application potential.