空气中直流条件下聚甲基丙烯酸甲酯沿面闪络实验

为研究直流条件下沿面闪络现象及其对绝缘材料的影响,搭建沿面放电系统,对聚甲基丙烯酸甲酯（PMMA）进行了不同电极间距下的沿面放电实验,并对放电前后材料表面的形貌特征、水接触角和表面成分进行分析。结果表明：施加电压过程中,电极附近会出现浅紫色光晕,随着放电距离的增大,闪络电弧的波动性和强度增强。放电后,电极之间形成明显的放电痕迹,越靠近阴极,痕迹越明显。随着放电次数的增加,材料表面呈现淤泥状,粗糙度增大,水接触角降低。材料表面的C1s含量降低,O1s含量升高,大量的C-C键断裂,生成C-O键、O-C=O键等亲水性基团,进一步提高了材料的亲水性。分析表明：材料表面微观形貌和表面元素对闪络电压有一定影响,对材料改性以提高闪络电压具有一定指导意义。

Experimental Study on Surface Flashover of PMMA Driven by DC Voltage at Atmospheric Pressure

In order to study the phenomenon of surface flashover and its influence on the insulation material under DC condition, surface discharge experiments on PMMA surface are carried out with different electrode distances. The surface morphology, contact angle and surface composition of material are analyzed. The results show that lilac corona occurs near electrodes during discharge process. Flashover arc fluctuation and intensity increase with discharge distance. Discharge mark is formed between electrodes after discharge. The mark is more obvious at locations closer to cathode side. Material surface becomes muddy with increase number of discharge. Roughness is increased, and water contact angle decreases too. After discharge, C1s content is decreased, however O1s content is increased. A large number of C-C bonds are broken to generate C-O bond, O-C=O bond and other hydrophilic groups which increase material hydrophilicity. The analysis of this paper shows that the surface micro topography and surface elements have a certain influence on the flashover voltage, and it has a certain guiding significance to improve the flashover voltage.