Wind Tunnel Testing on Coupling Mechanism of Wind-induced Vibration of Transmission Tower-line System

Wind-induced damages to the transmission tower-line system under the strong winds occur frequently. The wind-induced vibration response of the tower-line system has become the key issue in the investigation of the wind-induced damages of the transmission tower-line system. This paper carries out the investigation on coupling mechanism of the wind-induced vibration of the transmission tower-line system through an aeroelastic wind tunnel test. The wind-induced vibration responses of the single transmission tower and the transmission tower-line system under different wind attack angles and wind speeds are compared on the response statistics, distributions of power spectral density and the gust response factors. Test results show that the dynamic characteristics of transmission tower have changed due to the coupling effects of the transmission tower-line system. Not only are the natural frequencies along the longitudinal and lateral directions changed, but also the structural and aerodynamic damping ratios increase significantly. The analysis shows that, compared with the single tower, the gust response factors of the transmission tower-line system reduces significantly, and that the worst wind attack angle changes from 30° to 90°. The background component along the lateral direction increases significantly.