Study On Wind-induced Response And TMD Damping Effect Of Long-span Transmission Tower

Long-span transmission tower is the main carrier of electri c energy transmi ssion in China which is also a major project related to the life line of the coun try.Compared with the conventional transmission tower structure,the safety of t he transmission tower is more easily affected by wind-induced vibration becaus e the it is taller and more flexible.In this paper,the wind-induced vibration res ponse and vibration control scheme of the Yangtze River transmission tower inthe Nanyang-Jingmen-Changsha 1000kV UHV AC transmission line project aresystematically studied by wind tunnel test and numerical calculation of the aer oelastic model.The main research works are as follows:(1)This paper reviews the research status of wind-induced response analysis and vibration control methods of transmission towers or tower-line coupling systems,and introduces the necessity of such research es.Based on the existing theories,the main direction and content of the analysis are put forward.(2)In the finite element software,the beam element,rod element and mass element are used to simulate the rods,insulators and transmission lines of the transmission tower,and then the single tower structure,the tower-line coupling system and the simplified tower-line coupling system model are successively established.Modal analysis is used to study and compare the dynamic characteristics of the three structures,which provides a basis for the subsequent wind-induced response calculation and test.(3)In order to study the wind-induced vibration response results of long-span transmission towers,the parallel methods of numerical calculation and wind tunnel test were used to obtain the wind-induced vibration coefficients at different wind direction angles and the variation of wind-induced vibration coefficients at different parts of the tower body,and the comparison was made with the standard values.Compareing the single tower structure and line coupling system of displacement and acceleration response,the response is divided into background response and resonant response.This paper analyzes the features of them and combining the double tower,tower-line coupling system and simplify the tower-line coupling system of the wind vibration response of the contrast results and figures out some beneficial conclusion to the actual transmission line engineering design safety and reliability which provide guidance and basis for the subsequent design of T MD.(4)A tuned mass damper(TMD)is designed to control the first-order bending vibration mode of a long-span transmission tower based on the wind vibration response results and dynamic characteristics.The method proposed by Den Hartog is used to design the optimal parameters of TMD.Combined with wind tunnel test and numerical simulation calculation,the comparison of wind vibration response under the conditions with or without TMD is obtained.It can be seen that TMD can effectively reduce the displacement and acceleration responses of the transmission tower top under different wind direction angles and wind speeds.In addition,when the mass ratio range is between 0.5 and 5%,the greater the value is,the better the vibration reduction effect will be.However,when the mass ratio is 2%,it is more economical.In addition,the spectrum analysis of the response time history results can confirm the good control effect of TMD on the resonant response part of the transmission tower,which also verifies the correctness of the parameter selection.Combined with the test and calculation,a feasible wind vibration control scheme is provided for the long-span transmission tower structure which can provides a theoretical basis for the installation and use of the damper in the actual structure.