Dynamic responses analysis and disaster prevention of transmission line under strong wind

Abstract

Dynamic analysis of a typical transmission line section under strong wind was carried out. Firstly, according to the design conditions of the typical transmission line section, a three dimensional finite element analysis model of cup tower-stay frame tower-conductor-ground wire-insulator system was established in ANSYS. The initial tension force of the conductors was applied by the cooling method. Before the wind-induced vibration analysis, the form-finding analysis of conductors under self weight was carried out. Secondly, time history of the impulsive wind velocity was generated by spectral representation method. Time history of the impulsive wind velocity can be obtained by Fourier transformation in MATLAB program. The average wind pressure is applied to the tower line system by static method, and the impulsive wind pressure is applied by transient dynamic method. Thirdly, for the wind load case of design velocity, the wind-induced responses of the typical transmission line section were analyzed. Effect of the structural damping was considered by Rayleigh damping coefficients. Nonlinear transient analysis was employed for the wind-induced dynamic analysis of transmission line system. Under different wind velocities and directions, some wind-induced responses were obtained, which includes the tension forces of the conductors and the ground wires, axial forces of the towers, and the tension forces of the stray frame tower. Lastly, based on the analyzed results, the prewarning wind velocity for the typical transmission line section was determined. Some strengthen suggestions for the tower design in the strong wind zone was presented.