Study On Seismic Responses Of UHV Transmission Tower-line System

According to the regulation of current Code for design of seismic of electrical installations, when the seismic intensity is eight below, seismic checking for self-supporting tower may not execute. Seismic checking for tower can be also without considering of the effects of ground wires and conductors. However, recent studies have shown that it is necessary to consider the coupling effect between the towers and lines in the seisimic response analysis. Especially for the under-construction Ultra-high Voltage(UHV) transmission line in our country, of which the whole height of transmission towers are over 100m, it is important to study the seismic response of the tower-line system.In this thesis, the seismic responses of 1000kV transmission towers are numerically simulated comprehensively. Firstly, the finite element models, including a strain tower, a tangent tower and a typical transmission tower-line system are created in ABAQUS/CAE. Secondly, modal analysis is applied to the towers and tower-line system, low-order frequencies and modal shapes have been obtained.Response spectrum analysis is applied to the two towers, the preliminary results show that the towers have sufficient seismic capacity in variety of seismic intensities and site conditions. Then, the numerical simulation method of ground motion is discussed, accounting into the traveling wave effect and spatial coherence effect, the simulation of sparial correlative time histories of multi-point ground motion is realized. Finally,time history analysis to towers and tower-line system are finished in various working conditions. The statistical results suggest that the stress obtained by tower-line system analysis is larger than the single tower models.It is necessary to use tower-line system to study seismic performance of transmission tower, the two towers have sufficient seismic capacity.