Response Analysis Of UHVDC Transmission Tower-Line System Under Multi-Component Ground Motion And Multi-Support Excitation

Earthquake disaster is an important natural disaster threatening the safety of transmission lines.UHVDC transmission lines are more seriously threatened by earthquake disaster,because of their long total mileage,complex terrain in the region,many seismic zones and great flexibility of towers.However,the existing researches mainly focus on the seismic response analysis of AC transmission lines,and rarely consider the impact of terrain conditions on the seismic response.In view of the above problems,this paper first discussed the forward dynamic of seismic analysis of transmission lines.Then,a section of the line in Yunnan Province was selected to establish the finite element analysis model of the tower line system,and the influence of topographic conditions was introduced by changing the height difference between transmission towers.The multi-dimensional and multi-support excitation of the tower line system were carried out respectively under the condition of secondary site soil as the load model,so the multi-component characteristics of the earthquake and the traveling wave effect were considered.The time-history response analysis method was adopted to calculate the seismic response of the tower line system,in order to explore the influence of seismic excitation dimension on the seismic response,and the influence of seismic traveling wave effect on the seismic response of the tower line system.The results show that the axial force of components under three-direction seismic excitation is greater than the axial force under horizontal bi-directional and unidirectional excitation,the axial force of components under variable height difference tower line system is greater than the axial force under no-height difference tower line system,and the axial force under the influence of seismic traveling wave effect is greater than that under the influence of seismic traveling wave effect.It can be seen that ignoring the multi-dimensional seismic characteristics and traveling wave effect,as well as the topographic changes,so the effects of multi-dimensional characteristics,traveling wave effect and terrain change should be considered in the actual transmission lines.