Studies On Wind-induced Dynamic Response And Vibration Control Of Guyed Cat-head Transmission Tower-line System

High-voltage transmission tower-line system is all over the country, it is a lifeline engineering structure which is widely used. Its safe and reliable is directly related to the safe operation of the whole transmission systems. High-voltage transmission tower-line system has the common features of a high tower, a long span and a strong flexibility. Additionally, the period of the transmission tower-line system is quite long which is closer to the predominant period of the wind, so it is very sensitive to wind loads. The transmission tower-line system is often severely damaged due to the wind loads, and then it causes the paralysis of the entire power supply system, which are big losses to the social economics. Therefore, for transmission tower-line system, wind loads are very important design loads, the studies of its dynamic characteristics'responses and safety under wind loads have been the focuses of current research directions. Because guyed cat-head transmission tower-line system has the special structure, it has a very strong geometric nonlinearity that is leading to more complex mechanical properties, but now the studies of its dynamic characteristics'responses and safety under wind loads are really not many.Firstly, a finite element model of guyed cat-head transmission tower-line system is built, and then modal analysis is done. Natural frequencies and modes of different models are extracted, such as cat-head transmission single tower, guyed cat-head transmission tower and guyed cat-head transmission tower-line system. The results show that both the guyed and the transmission line affect natural frequencies of the whole transmission tower-line system.Secondly, dynamic response analysis of guyed cat-head transmission tower-line system under wind loads is calculated. Four different cases of wind loads including 0°,45°,60°and 90°are discussed, and then the values of displacement, velocity and acceleration responses are obtained under these pulsating wind loads. The results show that the maximum values of the vibration displacement, velocity and acceleration responses of transmission tower-line system under these pulsating wind loads are all too large, so the wind-induced vibration controlling is needed.Thirdly, after introducing the research, application and development of seismic energy dissipation, it mainly introduces mechanical properties and dynamic models of magnetorheological fluid dampers, then establishes the simulation model in Simulink based on modified Bouc-Wen model of this magnetorheological fluid damper, and at last it does the simulation analysis of mechanical properties.Finally, one simplified calculation method is used to obtain the overall mass matrix and stiffness matrix of guyed cat-head transmission tower-line system, and then it establishes the simulation model of wind-induced vibration of guyed cat-head transmission tower-line system under different cases of wind loads in Simulink. Based on the research of semi-active control algorithms of a structure and the specific installation locations of magnetorheological fluid dampers, it chooses two semi-active control methods which are the dual-modul control and the fuzzy control to control the wind-induced vibration of guyed cat-head transmission tower-line system by magnetorheological fluid dampers, and then establishes the wind-induced vibration control simulation model of guyed cat-head transmission tower-line system under different cases of wind loads in Simulink, analyzes and compares the control effects. The results propose new ideas and practices for the wind-induced vibration control of guyed cat-head transmission tower-line system.