大档距/高差线路非均匀覆冰下的脱冰跳跃特性研究

Research of Ice Shedding Jump Characteristics of Transmission Lines with Lager Span and High Elevation under Non-uniform Accreted Ice

摘要:

冰区输电导线上的覆冰脱落会减小绝缘间隙，可能引发闪络跳闸，威胁线路安全运行。针对目前基于有限元法的非均匀覆冰下导线脱冰跳跃特性研究的不足，采用有限元方法建立3档四分裂导线计算模型，研究非均匀覆冰和均匀覆冰对导线脱冰跳跃特性的影响，分析非均匀覆冰导线在档距、高差、覆冰厚度等参数下对最大脱冰跳跃高度的影响规律，并对现有经验公式进行改进。结果表明，最大脱冰跳跃高度与非均匀覆冰密切相关，非均匀覆冰下导线的脱冰跳跃高度可能大于均匀覆冰下的脱冰跳跃高度，且最大脱冰跳跃高度所在位置可能不在档距中点，更容易引发闪络跳闸事故。因此，所提非均匀覆冰下导线的脱冰跳跃特性对重冰区线路绝缘设计具有重要工程价值。

Abstract:

Ice shedding on transmission conductors in ice areas can reduce the insulation gap, which may trigger a flashover trip and threaten the safe operation of lines. At present, the research on ice shedding jump characteristics of conductor under non-uniform accreted ice based on finite element method is insufficient, so the calculation model of continuous three-span transmission line with quad bundle conductor is established by the finite element method. The effects of non-uniform accreted ice and uniform accreted ice on ice shedding jump characteristics of the conductor are studied, and the dynamic characteristics of transmission line conductors with non-uniform accreted ice after ice shedding under different parameters such as the span length, elevation difference and ice thickness are analyzed, and the existing empirical formula is improved. The results show that the maximum ice shedding jump height is closely related to non-uniform accreted ice, the ice shedding jump height of the conductor under nonuniform accreted ice may be larger than that under uniform accreted ice, and the position of the maximum jump height of transmission line conductors after ice shedding may not be at the midpoint of the span, more likely to cause flashover and trip accident. Therefore, the proposed ice shedding characteristics of conductor under non-uniform accreted ice have important engineering value for the insulation design of transmission line in heavy ice areas.