输电线路绝缘子串防冰闪措施研究

Study on Measures to Prevent Icing Flashover of Insulation Strings

2008年1—2月,南方地区严重的冰灾事故给部分地区电网造成了巨大的损失,绝缘子串冰闪是造成这次冰灾事故的主要因素之一,因此预防绝缘子冰闪对于保证覆冰地区输电线路安全运行十分重要。通过对绝缘子冰闪机理进行分析,文章比较了3种预防输电线路绝缘子串冰闪措施的特点,指出绝缘子串发生冰闪的主要原因是绝缘子串电压分布畸变和冰凌桥接导致融冰时形成了连续高电导水膜,并指出在一些防冰闪措施中,防污闪复合涂料(permanent room temperature vulcanized anti-contamination flashover composite coating,PRTV)并不能有效防止绝缘子覆冰,且会降低绝缘子冰闪电压,因此笔者不推荐采用PRTV预防冰闪。同时,因V型串和间插方式可有效调高绝缘子冰闪电压,这种方式在覆冰地区输电线路设计和改造中较实用。

In January and February 2008, serious ice disaster brought tremendous loss to some regional power networks in Southern and Central China. The icing flashover of insulator stings is one of the principal factors causing this ice disaster, thus the prevention of icing flashover of insulator strings is significant for the secure operation of transmission lines located in ice-covered regions. Through the analysis on icing flashover of insulator strings, the paper compares the characteristic of measures to prevent icing flashover of insulator strings of transmission lines, point out that the main reasons causing icing flashover of insulator strings are the aberration of voltage distribution along insulator string and the continuous high conductive water film that appears while the bridged ice icicles are molten. Moreover, it is also pointed out that in some measures to prevent icing flashover, the PRTV coating （permanent room temperature vulcanized anti- contamination flashover composite coating） cannot effectively prevent ice coating on insulator surface, meanwhile, PRTV coating may reduce the icing flashover voltage of insulators, thus it is not recommended to use PRTV coating to prevent icing flashover. The V-type insulator string and the insulator string composed by insulators with larger and smaller shed diameters alternatively can effectively increase the icing flashover voltage of insulator strings, so they are practicable approaches for the design and renovation of transmission lines in ice-covered regions.