高速气流环境交流电晕对硅橡胶表面憎水性分布的影响研究

Study on the Influence of AC Corona on Hydrophobic Distribution of Silicone Rubber Surface in High-speed Air Flow Environment

电晕是造成车顶绝缘子老化的主要因素之一。基于高速气流试验平台,试验研究了高速气流电晕环境下硅橡胶表面的憎水性分布,通过分析高速气流对电晕放电路径和放电电流的影响,讨论了憎水性分布发生偏移的原因。研究发现:高速气流环境下电晕强度较大时,憎水性丧失最严重的部位沿气流方向发生偏移。其原因是:当电晕放电沿针尖发展至针板间隙空间时,高速气流使得电晕放电路径沿气流方向偏转。气流速度一定时,离子所受电场力随电压的增大而增大,高速气流不易将其吹离针板间隙空间,电子在电场中运动的距离增长且电子平均自由程增大使得电子获得的能量增大,因而放电强度增大。研究结果可为高速铁路车顶高压绝缘设计与维护提供参考。

Corona discharge is one of the main factors causing the aging of the railway roof insulators.Based on an artificial experimental wind-tunnel platform,the influence of different intensity of AC corona on the distribution of hydrophobicity on the surface of silicone rubber was studied.The influence of airflow on corona discharge channel and current were analyzed.The reason for the deflection of the distribution of hydrophobicity in the high-speed airflow environment was discussed.The results reveal that the position of most serious hydrophobicity loss is offset along the direction of the airflow when the intensity of corona is large enough.Reason is that the main path of the discharge changes with the presence of high-speed airflow when the path developed in the gap of needle-plate.Meanwhile,when the speed of airflow is constant,electric field force acting on the particles raises with the increase of the corona discharge intensity,resulting the number of the particles blown away from the gap by the high velocity airflow decreasing.In addition,the distance that the electron moves in the gap is longer and mean free path of electrons increases,which makes the energy obtained by the electrons increased.Therefore the discharge intensity increases.The results can provide a reference for the design and maintenance of high-voltage insulation for high-speed railway.