微地形风场下架空输电导线风致振动特性分析

Analysis of wind-induced vibration characteristics of overhead transmission line in micro terrain wind field

为研究微地形下架空输电导线风振特性以完善输电线路抗风设计,采用计算流体动力学方法(CFD)模拟得出微地形下不同线路处风速及攻角变化规律,并推导输电导线相对运动时的脉动风荷载。建立跨越微地形的三跨输电导线有限元模型,利用谐波合成法(WAWS)模拟时间和空间相关的线路脉动风场,对导线施加风荷载,分析微地形下输电导线风振响应。研究结果表明:在微地形下,来流经谷口与山顶时加速明显,水平风速最大加速比达到1.42,坡前垂向风速不可忽略;相较平地风场,跨越山谷、山顶线路第二跨导线的跨中水平位移幅值分别增大58.27%和56.39%,导线水平张力和绝缘子风偏角度大幅增加,导线覆冰舞动可能导致空气间隙不足发生放电,在抗风设计时须增大设计风速;坡前线路风振位移减小,可适当减小安全裕度。研究结果可为复杂山地地形下输电导线抗风设计提供参考。

In order to study the wind-induced vibration characteristics of overhead transmission line under micro terrain to improve the wind-resistant design of transmission line,computational fluid dynamics(CFD)method was used to obtain the wind speed and angle of attack variation laws at different lines under micro terrain and to derive the pulsating wind and air dynamic loads during the relative motion of transmission line.The finite element model of three-span transmission line across micro terrain was established.The fluctuating wind field of the line with time and space correlation was simulated by using the harmonic synthesis method.The wind load was applied in the line and the wind vibration response of the transmission line under micro terrain was analyzed.The results show that under the micro terrain,the acceleration is obvious when the incoming flow passes through the valley and the top of the mountain.The maximum acceleration ratio of the horizontal wind speed reaches 1.42,and the vertical wind speed in front of the slope cannot be ignored.Compared with the flat wind field,the mid-span horizontal displacement amplitude of the second span conductor of the line across the valley and the mountain top increases by 58.27%and 56.39%,respectively.The horizontal tension of the line and the wind deflection angle of the insulator increase significantly,the ice galloping of the line may lead to insufficient air gap for discharge,and the design wind speed must be increased in the wind resistance design.The wind vibration displacement of the line before the slope is reduced,and the safety margin can be appropriately reduced.The research results can provide reference for the wind-resistant design of transmission line in complex mountainous terrain.