垭口微地形下档内线路不均匀覆冰研究

Research on Uneven Icing of Lines in Adjacent Towers Under Pass Micro-topography

明确垭口地形因子对垭口输电线路覆冰的影响规律,对山区输电线路的差异化防冰非常关键。该文基于水文分析中反地形理论提出山腰垭口,建立垭口风场数值模型,并通过风洞实验验证该模型。依据垭口风场分布,选定3类垭口线路的架设路径,得出垭口线路的风速区间。将初始状态下导线单次覆冰冰层厚度不得超过线径的7%作为覆冰步长取值依据,循环计算流场、粒子传输模型、热力学方程得出线路风速区间内导线的覆冰情况,进而得出垭口线路的冰荷载曲线,山腰、山脉、双山垭口线路冰荷载曲线在弧垂区分别出现了弯折、下行、下凹的走势。通过野外垭口线路自然覆冰实验,验证了覆冰计算的有效性,证实横跨垭口线路的不均匀覆冰性,不均匀覆冰规律与计算冰荷载曲线类似。计算不同地形因子组合下3类垭口的冰荷载曲线,并提出最大应力比概念,作为评判覆冰所引起线路事故可能性的标准,量化了不同垭口地形因子与线路最大应力比之间的关系。

Clarifying the impact of pass topographical factors on the icing of transmission lines in pass is crucial for the differential anti-icing of transmission lines in mountainous places.Based on the anti-terrain theory in hydrological analysis,the mountainside pass is initially suggested in this work,and a numerical model of the pass wind field is established.The model is then verified by wind tunnel test.According to the distribution of the pass wind field,the erection paths of three types of pass transmission lines are selected,and the wind speed range of the pass transmission lines is obtained.In the initial state,the thickness of the single ice coating on the wire should not exceed 7%of the wire diameter as the basis for the value of the ice-covering step.The flow field,particle transport model,and thermodynamic equations are cycled through calculations to determine the icing situation of the wire in the wind speed range.Then the ice load curve of the pass line is obtained.In the sag region of the line,the ice load curves of the mountainside,mountains,and mountain pass,respectively,have bending,falling,and concave trends.The pass line's natural icing experiment validates the accuracy of the ice model and confirmes the uneven icing over the pass line,and the law of uneven icing and the computed ice load curve are similar.The ice load curves of three types of passes under different combinations of pass topographic factors are calculated,and the concept of maximum stress ratio is proposed as a criterion for judging the possibility of line accidents caused by ice coating.The relationship between different pass topographic factors and the maximum stress ratio of the pass line is quantified.