Study on the Synergistic Enhancement of the DC Surface Flashover Performance and the Mechanism of the Superhydrophobic Coating Modified by Silicon Carbide
Xu Wenjie, Huang Zhengyong, Li Jian, Wang Feipeng, Su Fanyun
State Key Laboratory of Power Equipment & System Security and New Technology Chongqing University Chongqing 400044 China
Abstract：The insulation failure resulting from the wet and pollution surface flashover has become an obstacle to the safe and stable operation of electricity grid. Recently, the superhydrophobic coating has prospect in suppressing the wet and pollution surface flashover of the electrical facilities. Due to the ultra low adhesion, the water droplets disturbed by the external force such as wind could roll off from the superhydrophobic surface. The contamination on the surface of the electrical facility could be took away by the roll-off water droplet, hence the insulation of the electrical facility with a clean and dry surface is enhanced. However, the superhydrophobic coating tends to accumulate surface charge, leading to electric field distortion and surface flashover under DC voltage. A SiC/fluorocarbon resin superhydrophobic coating with excellent hydrophobicity and charge dissipation characteristics was developed, and the surface flashover performance and the enhancing mechanism of the coating were investigated. The surface topography of the fluorocarbon resin coating observed by the scanning electron microscope indicated that rough surface structure was constructed by the SiC fillers, thus superhydrophobicity of the SiC/fluorocarbon resin coating was obtained via the combination of the rough structure and low surface energy. The static water contact angle of the fluorocarbon resin coating with 40% SiC filler was 163.2°. Based on an artificial DC surface flashover platform, the surface flashover performance of the SiC/fluorocarbon resin superhydrophobic coating was investigated. The fluorocarbon resin coating with 40% SiC fillers shows the best surface flashover performance. Compared with those of silicone rubber, the dry and wet surface flashover voltages of the superhydrophobic coating can be improved by 62.1% and 90.6%, respectively. Water bind was formed on the silicone rubber after surface flashover, while large dry area appeared on the superhydrophobic coating due to the roll-off water droplet driven by the electric filed. The enhancing mechanism of the surface flashover performance was revealed via the surface charge dissipation and the superhydrophobicity of the coating. According to the surface potential measurement result, the surface charge dissipated faster on the fluorocarbon resin coating with more SiC fillers. Since the surface charge could hardly accumulated on the SiC/fluorocarbon resin coating, the electric filed distortion on the coating was relieved. The electrical trap distribution on the SiC/fluorocarbon resin coating was obtained via the isothermal surface potential decay method. The results show that the surface of the fluorocarbon resin coating with 40% SiC fillers was dominated by shallow-energy-level traps, and the trapped carriers were easy to escape, promoting the surface flashover voltage. Besides, the adhesion work between the water droplet and the superhydrophobic coating was proved to be low, and the water droplets driven by the electric field were easy to fall off the coating. And the dry area on the surface was expanded, enhancing the insulation strength of the coating. The SiC/fluorocarbon resin superhydrophobic coating with excellent hydrophobicity and charge dissipation characteristics shows an enhanced surface flashover performance under the DC voltage, which has an important reference value for improving the insulation strength of the electrical facilities under high humidity.
许文杰, 黄正勇, 李剑, 王飞鹏, 苏凡云. 碳化硅改性超疏水涂层协同增强直流沿面闪络性能及机理研究[J]. 电工技术学报, 2023, 38(9): 2480-2490.
Xu Wenjie, Huang Zhengyong, Li Jian, Wang Feipeng, Su Fanyun. Study on the Synergistic Enhancement of the DC Surface Flashover Performance and the Mechanism of the Superhydrophobic Coating Modified by Silicon Carbide. Transactions of China Electrotechnical Society, 2023, 38(9): 2480-2490.
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2023, Vol. 38 
