Seismic Response Analysis Of UHV Steel Tubular Tower

Transmission line plays a decisive role in power construction as an important lifeline engineering.UHV transmission line will gradually become the main mode of China's power supply to satisfy the large-scale,long-distance,high-efficiency power transmission requirements.UHV transmission line has the characteristics of high tower,large span and high flexibility,and is more susceptible to earthquake loads.Therefore,it is necessary and meaningful to analyze the seismic response of the UHV transmission tower-line system in order to ensure the safe operation of the power system.In this paper,1000 kV UHV steel tubar tower and tower-line system as the research object.the finite element models of UHV steel tubar tower and tower-line system are established by using finite element software ANSYS.By comparing the horizontal stress and sag of the conductor and ground wire in the self-weight equilibrium state,the theoretical and numerical results show the validity of the model.Block Lanczos method is used to analyze the two models of single tower and tower line system.The natural frequencies and modal shapes of the two models are extracted.The influence of conductor and ground wire on the self-vibration characteristics of single tower is analyzed.Based on the theory of response spectrum,the response spectra of different seismic intensity and site conditions are obtained according to the seismic design code.The seismic response of the maximum value of control variables such as tower top displacement,bearing reaction force and structural stress is analyzed,and the seismic capacity of steel tube tower is analyzed.Three typical seismic waves under different site conditions are selected,and the minimum square velocity method is used to modify the seismic wave baseline,and obtain closer to the actual seismic wave.The seismic response characteristics and laws of transmission tower and tower-line system model control variables,such as tower top displacement,rod internal force and base bearing reaction force,are compared and analyzed under the conditions of 8 degree fortification and rare seismic intensity,Which provides a certain theoretical basis and reference for seismic analysis and design of UHV transmission towers.In addition,This paper also analyzes the response regular of vertical earthquake to transmission-line system control parameters.Under the action of vertical earthquake,the displacement value of vertical conductor and ground wire and the bearing reaction force value have more significant increase than those of horizontal the direction.Therefore,it should pay attention.