Wind Vibration Response Analysis And Vibration Suppression Of Transmission Tower-line System

This paper studies two aspects of the dynamic characteristics of the transmission tower and line system and the vibration suppression of the transmission tower.First,based on the transmission tower test model,the finite element models of transmission tower,transmission line and transmission tower line system(two towers and three lines)were established,and modal analysis was carried out.Based on WAWS method,the fluctuating wind load was simulated,and the wind-induced response time history analysis of those two finite element models was carried out.The results show that the wind induced vibration responses of the models all have the characteristics of little response to the bottom and large response to the top of the tower,and the suppression of transmission tower's vibration should start from the top of tower.Modal test of the transmission tower was carried out by hammering method,and compared with the theoretical calculation results,the results show that the beam and rod hybrid model can better reflect the dynamic characteristics of the transmission tower.The same method was used to study the influence of the suspended transmission line,the tightness of the insulator and the sag of the transmission line on the first 3 order modes of the tower.It is found that when the insulator is in a tight state,the suspended conductor will reduce the first 2 modal frequencies of the tower,and the greater the sag of the transmission line,the greater the influence on the first 2 order frequency.The transmission line has no effect on the third order modal frequency.The transmission line will increase the first 3 order modal damping,the greater the sag of the line,the greater the influence on the damping.When the insulator is in a relaxed state,transmission line and the sag of the line has no effect on the first third order frequency of the tower,only increasw the modal damping.And the greater the sag of the line,the greater the damping effect.The state of insulators will affect the modal damping of the transmission tower.The tighter the insulators,the greater the modal damping of the transmission tower.According to the characteristics of wind vibration response and the spatial structure of the test model,a suspended TMD device was designed to suppress the first vibration mode of the tower.Through the optimization analysis of TMD parameters,the optimal frequency ratio(?_d=0.96)and the optimal damping ratio(?_d=0.10)were obtained on the premise of fixed mass ratio(?=0.03)and constant wind load.The experiment shows that the first step vibration of the transmission tower can be suppressed effectively by the designed TMD damping device,and the damping rate is 50.8%.