| High voltage transmission tower line system is a very important part of the power system.It has made significant contributions to our country’s economic construction.If the high voltage transmission tower line system is damaged,it will not only cause huge property loss,but also seriously affect everyone’s daily life.Therefore,it has great significance to ensure the safe operation of the transmission towers.High voltage transmission tower is a tall building.When subjected to strong winds,the tower cause complex vibrations or even collapse due to the coupling effect of the wires and towers.The spacer not only limits the relative movement between the splitting wires,but also maintains the geometry of the splitting wires,which facilitates the normal operation of the split wires.Therefore,it is necessary to study the dynamic characteristics of the transmission tower-line system,the wind-induced vibration response under the influence of wind load and the fatigue life of the spacers,helping to get some conclusion with reference value for practical applications.The following is the main content of this thesis:(1)Based on the AR method,this thesis,choose the most widely used Davenport wind speed spectrum to edit the program for simulating pulsating wind in MATLAB software.The program simulates the wind speed curves along different heights of the transmission tower line system and verifies the correctness of the simulation results.It provides the conditions for the subsequent calculation of the wind-induced vibration response.(2)According to the main force characteristics of the transmission tower,the BEAM188 beam element in the ANSYS software is used to construct the refined finite element model of the transmission tower.Based on the principle of parabolic shape finding,the LINK10 element is used to simulate the transmission wire and complete the shape-finding calculation of the transmission wire under the effect of gravity.Conductor isolation-string and spacer elements,a refined finite element model of the "two towers and three lines" transmission tower line system are established with conductor isolation-string,spacer,simulated by LINK8 and transmission towers,wires.The modal analysis find that the weak part of the transmission tower is the tower leg and the cross arm,which are prone to premature deformation.(3)This thesis calculate the load schedule of each node in the tower line system with the pulsating wind speed obtained in the simulation in Chapter 2Wind vibration response analysis are completed for single-tower and the "two towers and three lines" transmission tower line system according to Newmark-β method in ANSYS.The wind-induced vibration response of displacement,velocity and acceleration of single tower is compared with the tower-line system.It is found that the coupling of transmission lines,Conductor isolation-string,spacer bars and transmission towers has a certain amplification effect on the vibration of the structure.(4)The time-history curve of spacer bars at split conductors is obtained by analyzing the wind-induced vibration response of the tower line system,and the load spectrum and stress amplitude cycle number of the spacer is obtained by using the rain-flow counting method.Finally,the fatigue life of the spacer is estimated. |
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