输电线路绝缘子表面积污是污闪事故发生的前提，本论文从微观角度出发分阶段研究了绝缘子表面污层形成的过程，对于完善绝缘子的积污机理以及更加合理地预测绝缘子的积污特性具有重要意义。 综合考虑空气流场、电场和重力场的影响，研究了绝缘子周围污秽颗粒的输运过程。通过建立污秽颗粒运动和沉降模拟试验平台和两相流仿真计算模型，分析了流体曳力、极化力、电场力和重力对荷电污秽颗粒运动特性的影响。绝缘子周围的流场分布和电场分布共同影响污秽颗粒的运动特性，低速涡流区和强场区污秽颗粒的沉积量较大。 首次利用原子力显微镜精确测量了绝缘子表面对污秽颗粒的粘附力，确定了数十微米的污秽颗粒所受的粘附力为μN量级，比污秽颗粒在运动过程中的受力高数个数量级。硅橡胶在污秽颗粒与其碰撞的过程中易变形，对污秽颗粒的粘附力较大，由颗粒碰撞模型可得污秽颗粒在复合绝缘子表面的粘附概率较高。绝缘子表面的电荷积聚还会对污秽颗粒产生长程吸引力的作用从而吸附更多的污秽颗粒。 提出微尘颗粒沉积在绝缘子表面以后还会发生放电固着的过程，通过放电试验模拟了该过程，并利用“胶带试验”对污层固着的程度进行了半定量的评价。通过对固着前后污层的微观形貌和微观结构进行深入分析，发现污层固着是多次放电活动的累积效应，表面放电局部小电弧产生的高温对污秽颗粒的烧结作用是导致污层固着的主要原因。开展了降雨对表面污层清洗作用的试验研究，结果表明雨强、绝缘子表面憎水性和污层固着等因素共同影响降雨的清洗效率。 微尘颗粒在电场力作用下的沉积、在绝缘子表面的粘附、在放电条件下的固着以及在降雨条件下的清洗四个环节共同起作用，导致带电绝缘子比不带电绝缘子积污严重、直流绝缘子比交流绝缘子积污严重、复合绝缘子比瓷\玻璃绝缘子积污严重以及绝缘子积污量沿串分布不均匀。 通过模拟微生物的生长环境，利用真菌孢子在硅橡胶试片表面培养了生物污层，发现硅橡胶材料可为真菌生长提供营养物质。生物污层可自行生长，在绝缘子表面的分布与其生长条件有关。潮湿的生物污层可显著降低硅橡胶试片的电气性能，在硅橡胶材料中添加抗微生物剂可有效抑制生物污层的生长。
The contamination of the transmission line insulator surface is the premise of the pollution flashover accidents. This dissertation studied the forming process of the pollution layer on transmission line insulators by stages from microscopic view. It will be of great significance for perfecting the contamination mechanism of the insulators and forecasting the contamination characteristics of the insulators more reasonably.The transport process of the pollutional particles was studied by considering the effects of the air fluid field, the electric field and the gravitational field comprehensively. An experiment platform and a simulation model of two-phase flow were set up to analyze the influences of the fluid drag force, the polarization force, the electric force and the gravitational force on the motion characteristics of the charged particles. The fluid field distribution and the electric field distribution around the insulators influence the motion characteristics of the particles jointly. The contamination will be heavier where the low-speed vortexes form and where the electric field is stronger.The adhesion force of the pollutional particles on the insulator surface was measured precisely for the first time. The adhesion force of the particles with diameters of several tens of micrometers was confirmed to be with the magnitude of micro-Newton. The adhesion force is several orders of magnitudes higher than the forces acting on the moving particles. The collision with the pariticles will deform the silicone rubber, producing stronger adhesion force on the particles. According to the particle collision modle, the adhesion probability of the particles on the composite insulators will be higher. It was put forward that dust particles would be fixed under the effect of the discharge activities after they deposited on the insulators. The fixation process was modeled by discharge experiments. The fixation degree was characterized by tape tests semiquantitatively. By deep analysis of the microtopography and microstructure of the pollution layer before and after fixation, it was found that the fixation of the pollution layer was induced by the accumulative effect of repeated discharge activities. And it was considered that the sintering of the particles under the high temperature produced by the arc discharge was the main reason causing the fixation of the pollution layer. Then the cleaning effect by rain was studied by experiments. The rainfall intensity, the hydrophobicity of the insulator surface and the fixation of the pollution layer influence the cleaning efficiency jointly.The four successive steps, which are deposition under the electric force, adhesion on the insulator surface, fixation under the discharge activities and cleaning by the rainfall, work together and will lead to the following contamination results. The contamination of the live-line insulators will be severer than the insulators which are not subjected to high voltage. The contamination of the DC insulators will be severer than the AC insulators. The contamination of the composite insulators will be severer than the porcelain insulators. The distribution of the contamination will be non-uniform along the insulator string.Biological contamination layer was cultivated on the silicone rubber samples using fungal spores by imitating the growing environment of the microorganism. It was found that the silicone rubber can provide nutrient substance for the growth of the microorganism. Biological contamination layers can grow by themselves and their distribution on the insulator surface is related to the growing conditions. It was shown that the wet layer could reduce the electrical property of the samples greatly, and the addition of anti-biological agents to the silicone rubber could suppress the formation of the biological contamination layer effectively.
