染污硅橡胶在不同憎水性时的污闪特性

研究了硅橡胶平板模型在不同憎水性条件下的污闪特性。试品以定量涂刷的方式染污,通过控制迁移时间,使固体污层获取不同程度的憎水性能。以污层表面的液滴面积最大值来代表污层的憎水性强度,分析污层憎水性能对平板模型的污闪电压、污层电导以及电弧发展过程的影响。随着污层憎水性能的改善,试品污闪电压逐步上升。污闪电压与液滴面积最大值存在关联,但两者间的分散性随污层憎水性能的改善而增加。污层表面水珠形态对电弧发展过程有重要影响,当污层表面水珠能形成连续水膜时,电弧通道集中且污闪电压低;当污层表面水珠呈离散分布时,放电区域分散且污闪电压高。根据污闪试验结果以及不同憎水性强度污层表面的液滴形态,将亲水性表面HC7细分为HC7A、HC7B、HC7C和HC7D四种状态。HC7B状态下,污层憎水性能虽然很微弱,但相对污层完全没有憎水性的情形(HC7C和HC7D),试品的污闪电压有明显的上升。因此,依据HC7B状态下的污闪电压设计复合绝缘子结构,可以在保证绝缘子安全裕度的同时,优化绝缘子的结构高度。

Flashover Characteristic of Polluted Silicone Rubber with Different Hydrophobicity

This paper introduces the flashover characteristics of polluted silicone rubber plate samples with different hydrophobic properties. By virtue of quantitative brushing method, samples were polluted by controlling hydophobicity transfer time to obtain different hydrophobic properties . The maximum value of droplet area on the pollution layer stood for the state of surface hydrophobicity. The impacts of hydrophobicity on flashover voltage, pollution resistance and the development of arc were studied. Test results show that flashover voltages of samples increase with the improvement of surface hydrophobicity. A correlation exists between flashover voltage and the maximum value of droplet area. However, deviation increases from hydrophilic state to hydrophobic state. The morphology of droplets has a great effect on arc development. When drops form continuous water film, the number of arc paths is limited and the value of flashover voltage is low. However, when the drops on the surface are spherical and scattered, discharge areas are scattered s and the flashover voltages are high. According to the results of flashover tests and the different patterns of droplets, hydrophilic surface HC7, is subdivided into HC7A, HC7B, HC7C and HC7D respectively. Despite very unobvious hydrophobicity of HC7B, flashover voltages of samples with HC7B are obviously higher than those with totally hydrophilic states, such as HC7C and HC7D. Therefore, if the configuration structure is designed according to the flashover voltage related to the HC7B state, structure height of composite insulators can be shortened with the ensured safety.