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