【作者】 陈刚；

【导师】 苑舜； 蔡志远；

【作者基本信息】 沈阳工业大学 ， 高电压与绝缘技术， 2011， 博士

【摘要】 近年来,全世界各地的输电线路均遭受了覆冰带来的危害。相对电力系统遭遇的其他自然灾害,持续的覆冰气候常带来更严重的后果,轻则发生冰闪,重则导致杆塔倒塌,线路断线,甚至电网瘫痪。如何有效地减少绝缘子上冰闪的发生,阻止绝缘子上冰柱的桥接,提高绝缘子覆冰闪络电压,这些已经成为了亟需解决的难题。本论文从绝缘子覆冰的形成过程及主要影响因素的分析出发,回顾了国内外对于绝缘子防覆冰措施的研究成果,总结了目前绝缘子防覆冰的措施。为了研究绝缘子的覆冰问题,文中介绍了人工覆冰气候室的平台搭建,具有良好的可控、可调及实时监测功能。绝缘子的覆冰是一个非常复杂的过程,本文从热平衡的角度出发建立了覆冰的热平衡方程出发,研究了绝缘子覆冰的热力学过程,分析了空气中的液水含量以及风速等因素对于覆冰形成过程的影响。同时提出了应用组合RTV涂层的方式来防止绝缘子覆冰的新方法,既能在平时的运行中降低泄漏电流,又能够在覆冰期达到较大的泄漏电流,从而弥补了目前单一应用半导体硅橡胶在绝缘子表面会长期产生较大泄漏电流而引发大量电能损耗及硅橡胶易热老化的主要缺点。并且在RTV基础上研制出半导体RTV,与RTV共同应用在绝缘子上形成组合RTV,并测试了涂料的憎水性能、半导电性能,并且在大型的覆冰气候试验箱中进行了大量的覆冰模拟试验,测试涂料的实际防冰性能。本论文建立了基于有限元法的长串悬式瓷绝缘子模型,通过对绝缘子表面分别涂覆不同厚度的半导体硅橡胶、普通RTV、组合式硅橡胶后的电场分析,在理论上分析了涂覆不同种类涂料后的防覆冰效果,分析了各种涂料对于绝缘子的电场的均匀化效果,并优化计算得出了各种类涂层的最佳厚度。更多还原

【Abstract】 In recent years, the transmission lines were suffered from ice disaster all over the world. Compared with other natural disasters, long-term snow always brought more serious damages.In this paper, the causes of ice formation on power lines and insulators are studied. Some methods used to prevent icing on insulators are summarized. The construction of the climate room is described in detail.Ice coating is a complex process of the collision between overcooling water drops and insulators. Thus based on the thermal equation of ice covering, this paper had a research in the thermodynamics process of ice covering, analyzed the water loading of the air and the wind speed’s impact on the ice coating process. In this paper, a combined method of silicone rubber with different volume resistivity was proposed for de-icing. The volume resistivity of RTV was adjusted by adding conductive fillers. The method was focused on the problem that if the insulators were coated merely by semiconducting silicone rubber, in the days without snow, the large leakage current will bring enormous energy loss and cause thermal ageing of coatings. With this method, the leakage current will be small in the normal operation days and increase rapidly in snowy days, the energy loss and thermal ageing will be both weakened. This kind of silicone coating is developed successfully based on the RTV silicone coating. The coating’s characteristics of hydrophobicity and semiconductivity were tested by experiments. Experiments were carried out to validate the effectiveness of the semiconducting RTV coating in a climate-controlled chamber.In this paper, a finite element model of long porcelain insulator string was calculated to explain the mechanism of combined RTV, normal RTV and semiconducting silicone rubber on de-icing and electric field homogenization. The best thicknesses of coatings which should be painted were also discussed.更多还原