运行复合绝缘子表面憎水特性及微观结构研究

表面憎水性和憎水恢复性是复合绝缘子的重要性能,可以有效减少输电线路沿面闪络事故的发生。为了更好地理解运行复合绝缘子的表面状态,采用多种材料表征方法系统研究了两支运行10年的复合绝缘子伞裙的表面微观结构及憎水特性,并与未运行的样品进行对比。结果表明:由于小分子的扩散,在表面纳米级的深度范围内,运行样品与未运行样品具有相同的化学结构。运行样品的老化发生在表面深度为56~94μm处。此外,运行样品表面形貌粗糙程度、孔隙率显著增加,导致其表面接触角较大,憎水性恢复速率较快。然而运行样品的饱和吸水率也较高,是未运行样品的5~8倍。老化形成的裂纹、孔隙是运行样品憎水性恢复速率加快与吸水率上升的主要原因,但这些孔隙也为小分子的扩散和水分的入侵提供了通道。

Study on Surface Hydrophobic Properties and Microstructure of Serviced Composite Insulator

Surface hydrophobicity and recovery of hydrophobicity are important properties of composite insulators, which can effectively reduce the probability of flashover accidents on transmission lines. In order to understand the surface states of serviced insulators, several material characterization techniques were used to investigate the surface microstructure and hydrophobicity of two composite insulator skirts serviced for ten years, and then compared with the un-serviced insulator. The results show that due to the diffusion of micromolecule, the serviced and un-serviced samples have similar chemical composition in nanoscale depth from the surface. The ageing of serviced samples is happened in the depth range from 56 μm to 94 μm from the surface, and the roughness and porosity of serviced samples increases obviously, which would lead to the increase of contact angle and hydrophobicity recovery rate. The saturated water absorption of serviced samples is about 5 to 8 times higher than that of the un-serviced sample. The cracks and holes generated after ageing are the main reasons for the increase of hydrophobicity recovery rate and water absorption of the serviced samples, however, these holes provide paths for the diffusion of micromolecule and invasion of water at the same time.