绞线带电雨凇覆冰后的起晕电压下降趋势研究

Research on Decrease Regularity of stranded conductor Corona Onset Voltage after Energized Glaze Icing

雨凇会在导线表面生产出较长且尖锐的冰柱,从而影响导线的电晕起始特性;国内外研究机构已针对输电线路覆冰以及覆冰对导线电气特性的影响等问题做了大量且深入的研究,但大多忽略了运行导线发生带电覆冰的事实,且未针对带电覆冰后的起晕电压下降等问题进行深入研究;为研究不同电场带电覆冰形态对起晕电压的影响规律,在人工气候室针对四种绞线进行带电雨凇覆冰后的工频电晕试验,利用紫外光子数和拟合法测量了不同覆冰形态所对应的起晕电压值,并建立有限元电场分布模型以验证试验的正确性。结果表明:覆冰后的导线表面起晕电压会严重下降;不同场强覆冰后的起晕电压也不同;覆冰时间的增加会使起晕电压持续下降,但速度变慢且饱和;直径越粗的导线覆冰后的起晕电压越高;电导率不会改变雨凇覆冰形态,但较高的盐浓度会降低起晕电压值;雨凇冰棱越尖细则对电场的畸变作用越大,相应的起晕电压值也会越低。所得结论可为冰区的架空线路电晕放电特性研究提供一定的参考。

Sharp glaze icicles growing on surface of stranded conductor will impact corona onset voltage（COV）. Although the domestic and foreign scientists have done much research on icing conductor, they always ignore the fact that operating conductor energized icing when studying actual wires. In addition, there has been no in-depth analysis of how glaze influents COV of conductor. Therefore, a series AC corona test of energized glaze icing on four kinds of wires was implemented in Artificial Climate Chamber, UV imaging technology and/-U curve fitting were adopted to measure and analyze COV under different icicle shape, then finite element model was established to analyze distortion regularity of field. Results show that glaze can decrease COV of wires significantly. Glaze icicle in diverse shapes lead to different COV values. Increasing in icing extent will reduce COV continuously while the speed of decline slows down gradually. In the same icing time, thicker conductors will get higher COV than thinners. High conductivity water will cause COV to decrease obviously but has no effect on glaze shape. Longer and sharper Glaze icicle will make electric field distorted more seriously. Conclusion of this paper can provide selection and design reference for transmission line in glaze area.