雨凇对导线起晕电压影响规律的研究

Influence of Glaze on Corona Inception Voltage of Stranded Conductor

雨凇对输电线路的安全威胁极大,形成的冰柱会使得导线表面电场发生畸变进而影响电晕起始特性,国内外针对导线电晕特性进行了大量研究,但大多采用铝管来模拟实导线,且尚未深入分析覆冰对导线起晕电压的影响规律。利用人工气候试验室完成对LGJ-185/25钢芯铝绞线雨凇覆冰后的交流电晕试验,采用紫外成像仪及曲线拟合法对导线起晕电压进行测量并分析,并根据雨凇冰柱形态建立有限元模型进行最大场强计算。结果表明:雨凇会导致绞线起晕电压值的降低;覆冰程度的增加会使得绞线起晕电压持续下降但逐渐趋于饱和;雨凇形态不随电导率的不同而发生改变,但盐浓度的增加会使得绞线起晕电压继续下降。所得结论可为雨凇频发区的输电线路设计及选型提供依据。

Glaze affects secure operation of transmission line seriously,and icicles caused by glaze makes the electric field on conductor surface distorted and then the corona onset voltage characteristic of conductor is affected.A lot of researches on corona characteristics of conductors are performed home and abroad,most of them utilize aluminum pipes to simulate actual conductors and the influences of ice-coating on corona onset voltage of conductor are not analyzed in depth.A series of AC corona tests for ice-covered steel cored aluminum stranded wire LGJ-185/25 due to glaze are implemented in artificial climate chamber,in the tests the ultraviolet imager and curve fitting method are used to measure and analyze the corona onset voltage of stranded conductor,and according to the form of glaze-caused icicles a finite-element model is established to calculate the maximum field strength.Test results show that glaze leads to the decrease of corona onset voltage of stranded conductor;the increase of ice-coating thickness makes the corona onset voltage of stranded conductor continuously decreased and finally it gradually decreases to its steady value;the form of glaze does not changed with different conductivities of freezing water,however the increase of salinity makes the corona onset voltage of stranded conductor continuously decreased.The obtained results are available for reference to the design of transmission lines located in the region where the glaze frequently occurs.