山区输电线路跳线风偏状态方程及临界风速研究

为研究山区微地形中的竖向风速对跳线风偏的影响,基于刚性直棒法对导线、跳线及绝缘子串增加竖向风荷载分析,确定跳线处最大风偏位移值作为风偏指标,建立风荷载作用前后跳线静力平衡平面的几何变换关系,提出了考虑竖向风速影响的跳线风偏状态方程。建立半径5 km的地形模型,包含跳线风偏事故地点与微气象站点,采用数值模拟方法将微气象站点风速推演到事故地点风速,获得了考虑微地形影响的跳线风偏闪络事故风速。将事故线路参数及竖向风速代入跳线风偏状态方程,得到跳线风偏临界水平风速,通过与事故风速进行比较验证了跳线风偏状态方程的可靠性。最后根据风偏状态方程分析竖向风速的变化对跳线风偏临界水平风速的影响。结果表明:随着竖向风速的增大,跳线风偏临界水平风速线性减小,当风攻角为20°时临界水平风速可降低16%。考虑竖向风速影响的跳线风偏临界水平风速取值较为安全,建议在山区输电线路跳线设计过程中加以考虑。

Study on wind-induced swing state equation and critical wind speed of jump lines in mountainous areas

To study the influence of vertical wind speed on the wind-induced swing of jump lines in mountainous micro-topography, the vertical wind load on the conductors, jump lines, and insulator strings was analyzed based on the rigid bar method. The maximum displacement of wind-induced swing at the jump lines was determined as the index of wind-induced swing. The geometric transform relation of the static balance plane of jump lines was established before and after the wind load. Then the wind-induced swing state equation was proposed considering the influence of vertical wind speed. A terrain model with a radius of 5 km was established, including the accident site of the wind-induced swing of jump lines and the micrometeorological station. The wind speed of the accident site was deduced from the wind speed of the micrometeorological station by using the numerical simulation method to obtain the accident wind speed of wind-induced swing considering the influence of the micro-topography. The parameters of the accident line and the vertical wind speed were substituted into the wind-induced swing state equation to obtain the critical horizontal wind speed of the wind-induced swing. Then the reliability of the wind-induced swing state equation was verified by comparing the accident wind speed and the critical horizontal wind speed. Finally, the influence of variable vertical wind speed on the critical horizontal wind speed of wind-induced swing was analyzed according to the wind-induced swing state equation. The results showed that with the increase in vertical wind speed, the critical horizontal wind speed of wind-induced swing decreased linearly. When the wind attack angle was 20°, the critical horizontal wind speed could be reduced by 16%. Therefore, the critical horizontal wind speed of the wind-induced swing was much safer considering the influence of vertical wind speed which should be considered in the design of jump lines for mountainous areas.