Research On Dynamic Response Of Transmission Tower-Line System Based On Beam-Column Model

With the rapid development of the national economy,the scale of the power system has also grown rapidly.As an important link in the process of large-capacity and long-distance power transmission,transmission lines have grown rapidly in length.Compared with the past,the condition monitoring of transmission lines is more important to ensure the safe and stable operation of the power system.The transmission tower s have a large number of components,and the flexibility of the tower-line system is large,resulting in elements in great number and time-consuming dynamic calculation,which makes it difficult to meet the requirements of rapid calculation.Therefore,it is very important to find a method for calculating the equivalent stiffness of the tower that has a wide range of applications and is more convenient to operate.This paper proposed a method based on finite element model for calculating the stiffness matrix of transmission towers,and the dynamic response of transmission tower-line system under wind load was analyzed.The main contents include the following aspects:1.According to the structural characteristics of transmission towers,a method for inversely calculating the stiffness matrix based on the finite element calculation results is proposed,and the main principles and calculation steps of the method are given.Then MATLAB calculation scripts are written according to the calculation steps.2.The method was applied to drum-shaped transmission towers.Using the displacement of key nodes as an index,the calculation error of the equivalent beam-column model and the original truss-beam model is analyzed,thus the applicability of the stiffness equivalent method in the transmission tower structures is verified.3.On the basis of reasonable calculation results of a single tower,the equivalent beam-column model is used to establish a transmission tower-line system model,and its validity in the calculation of the wind-vibration response of the tower-line system is verified.From the horizontal displacement of the tower top and of the lowest point of the wire,the beam-column model has good accuracy in the dynamic simulation of the tower-line system.Using the equivalent beam-column model instead of the truss-beam model can significantly reduce the number of elements and shorten the dynamic calculation time by 70%.4.The equivalent beam-column model is utilized to study the dynamic response of the tower-line system under different wind loads.The data fitting of the simulation results under different basic wind speeds show that: for the top of the tower,the relationship between the mean displacement and the basic wind speed can be depicted approximately by a quadratic function;for the lowest point of the wire,the relationship between the mean downwind displacement and the basic wind speed approximates a quartic function.