| Long-span transmission lines play an important role in China’s modern economic construction as an important part of large-scale lifeline projects.As a large-span "tower-cable" connected structure,the transmission tower-line system has a small stiffness and uneven distribution along the tower height,and a complex tower-line coupling vibration effect,which makes the structure respond significantly under dynamic loads.Therefore,it is an urgent problem to study the dynamic response of the transmission tower line system and propose effective measures to reduce the structural dynamic response to ensure the normal use of the structure.This thesis takes a transmission line located in the coastal area of China as the research background,conducted field measurement of the transmission line,studied the coupled dynamic model of the transmission tower line system,and the dynamic response under the action of strong wind and strong earthquake loads.Established a dynamic analysis method for the coupling effect of transmission tower line systems equipped with energy dissipatting devices.In this thesis,a three-node isoparametric suspension element model with torsional degrees of freedom is used as a sub-conductor,a two-node space beam element model is used to simulate a spacer,and a multi-split conductor model is established.The process is derived in detail.Under the same conditions,the dynamic characteristics of a single suspension cable model and a split wire model are compared and analyzed,and the results show that the dynamic characteristics of the two have little effect on the low order.In this thesis,a multi-split conductor model and a suspension cable structure are used to simulate the transmission conductor and the ground wire respectively.Based on the serial multi-degree-of-freedom model,a coupled dynamic model of the transmission tower line system is established.The dynamic characteristics of the transmission tower line system were identified through field measurement,and the results were compared with the calculation of the tower line coupling dynamic model and the calculation of the finite element model.After comparison,the results show that the calculation results of the dynamic model are highly accurate and time-consuming.In this thesis,the coupled dynamic model of the transmission tower line system is taken as the research object,and its dynamic response under strong wind loads and earthquakes are studied respectively,and compared with the finite element results to verify the accuracy of the model and the rationality of the research method.At the same time,a comparative analysis of the transmission tower line system with and without the line is carried out.The results show that the calculation method of the dynamic model is accurate.Under the action of dynamic load,the transmission line has a great influence on the dynamic response of the transmission tower and cannot be ignored.Finally,considering the significant vibration of the transmission tower line system under the dynamic loads,a dynamic analysis method for the coupling effect of the transmission tower line system with vibration damping devices is established.Based on the passive friction damper,the research on the vibration control of the transmission tower line system is carried out.The vibration reduction effect of the transmission tower line system structure is analyzed,and the parameter analysis of the damper is performed.At the same time,the dynamic response of the transmission line with and without the damper is analyzed.The results show that the damper can effectively reduce the dynamic response of the transmission tower and has little effect on the transmission line. |
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