| As the carrier of high voltage electric energy transmission,transmission line systems is an important lifeline project.Because of the characteristics of high flexibility and long span,the transmission line systems has very strong geometric non-linearity and is very sensitive to wind load.Transmission towers often collapse due to wind-induced vibration.The vibration of transmission tower and transmission line affects each other,which makes the vibration of transmission line systems more complicated under wind load.It is of great significance to analyze the wind-induced vibration response characteristics of transmission line systems and to study the wind-induced vibration control method.Based on the 110 KV high voltage transmission tower project,the main research contents are as follows:(1)The ANSYS fine modeling scheme of transmission line systems is studied.The transmission tower and transmission line are simulated by three-dimensional beam element and pole element respectively,and the accuracy of transmission line simulation is verified by the mechanical model of catenary.The finite element model of "three towers and two lines" for transmission line systems is established.The basic properties of wind load are analyzed,and the numerical simulation method of fluctuating wind load is studied.The average wind is simulated by exponential wind section and the fluctuating wind is simulated by Davenport spectrum.The wind field fluctuating wind velocity time history sample of transmission line systems is obtained by MATLAB program by linear filtering method,and the wind load of transmission line systems is calculated by wind velocity time history.(2)The dynamic characteristics of single tower and transmission line systems are analyzed based on the finite element model.The results show that the out-of-plane vibration mode of transmission tower is obviously influenced by the coupling effect,and the coupling effect has little effect on the in-plane vibration of transmission tower-line system.Based on the nonlinear timehistory algorithm,the wind-induced vibration response of transmission line systems at 0° and 90°wind direction angle is calculated.The response characteristics and the coupling mode of transmission line systems are analyzed.The root mean square(RMS)of tower top displacement response in each wind direction angle is much larger than that in single tower case.The background response component of tower top displacement in 90° wind direction angle is greatly increased,and the coupling effect of tower line is much greater than that of 0° wind direction angle.The in-plane coupling effect between the transmission tower and the transmission line is realized by the differential dynamic tension at the end of the transmission line.The main material stress of the transmission tower is similar to the top displacement of the tower.The second floor of thetransmission tower is the maximum stress of the main material,and the compressive stress is greater,which is the dangerous position of collapse.(3)the simplified multi-particle model of transmission tower is established.Based on the simplified model,the damping characteristics of tuned mass damper(TMD)are studied.According to the response characteristics of transmission tower,the parameters of tuned mass damper are optimized,and the optimal damping effect is obtained.The design scheme of bi-directional TMD is analyzed.The results show that the tuned mass damper has a good control effect on the vibration control of the transmission tower.The damping effect of tower top acceleration is obviously better than that of tower top displacement.The damping effect of main material stress on tower body is similar to that of tower top displacement,and the damping effect of each response quantity of0 °wind direction angle is greater than 90° wind direction angle.(4)The wind vibration control effect of viscoelastic damper on transmission tower is analyzed.Aiming at the first mode shape of transmission tower,the optimal control algorithm of LQR is used to optimize the parameters of viscoelastic dampers,and the effect of structural vibration control close to the active control device can be obtained.After optimizing the parameters of viscoelastic dampers,the displacement of tower top can achieve a good damping effect.The vibration reduction effect of acceleration is obviously greater than that of displacement,and the maximum stress damping rate of tower body is similar to that of top displacement of tower.By using particle swarm optimization algorithm,the number of viscoelastic dampers installed is only 41.6% of the full dampers,but the vibration reduction rate of each response of the transmission tower can reach more than 90% of the full dampers.The rational arrangement of passive control devices can greatly improve the utilization efficiency of dampers.(5)Based on the characteristics of wind-induced vibration response of transmission line systems,the design scheme of damper between transmission tower lines is studied.A viscoelastic damper is designed to reduce the vibration transfer between the transmission tower and the transmission line by controlling the large vibration of the transmission line.The damping method of transmission line-damper and the general design curve of damper are analyzed,and the principle of selecting the optimal parameters of damper for controlling in-plane and out-of-plane vibration of transmission line is determined.The results show that the vibration reduction of transmission line can effectively reduce the vibration of transmission tower.Under each wind direction angle,the displacement of the tower top and the stress of the main material of the tower body are very obvious.The damper increases the modal damping ratio of the transmission line and reduces the first order resonance response of the transmission line.Under the 90° wind direction angle,the power spectrum of the Y displacement and the dynamic tension difference at the end of the transmission line are obviously reduced at each resonance frequency point,and the vibration of Y-direction ofthe transmission tower and the transmission line are coupled with each other.Under the action of dampers,the mutual transmission of vibration is effectively reduced. |
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