Research On Wind-induced Vibration Response Of Crossing Transmission Line Under Downburst

The downburst strong wind field has great harm to overhead transmission lines,and the safe operation of crossing transmission line is of great significance to the crossing transmission line itself and the crossed line.In order to research on the wind-induced vibration response of crossing transmission line in downburst strong wind field and improve the safe operation level of crossing transmission line,the main contents of this paper are as follows:Based on the impinging jet model,two-dimensional numerical simulation of downburst wind field is carried out by using computational fluid dynamics software.The vertical and radial wind profiles of horizontal wind speed in downburst wind field are analyzed in detail.The characteristics of downburst wind and atmospheric boundary layer wind are compared to study the difference between them.By changing the initial outflow diameter and height of downburst wind field model,the influence of initial outflow conditions on the maximum horizontal wind speed(wind speed value and its location)in downburst wind field was studied.The finite element model of the tower-line system of the "strain-tangent-strain" crossing transmission line is established,and the wind-induced vibration response of the crossing transmission line under downburst current is numerically calculated.The windinduced vibration response of crossing transmission line under downburst is analyzed from three aspects: the top displacement of transmission tower,the variation curve of the peak of displacement response along tower height and the element axial force at the dangerous points of transmission tower.The wind-induced vibration response of crossing transmission line under the action of wind in the atmospheric boundary layer is numerically calculated and compared with that under the action of downburst.The results show that the downburst wind field poses a greater threat to the crossing transmission line than the atmospheric boundary layer wind field through the comparative analysis of the displacement response at different heights of transmission towers,the unit axial force response at dangerous points of transmission towers and the tension response of suspension strings under the two wind fields.Therefore,in order to improve the safe operation level of crossing transmission line,the impact of downburst strong wind field should be considered in the design stage of the lines.