地震作用下输电线路塔线耦合的动力响应数值分析

NUMERICAL SIMULATIONS ON DYNAMIC RESPONSES OF A TRANSMISSION TOWER-CONDUCTOR COUPLING SYSTEM UNDER EARTHQUAKE ACTION

输电线路由基础、杆塔和架空导线组成,杆塔和架空导线的塔线耦合作用显著。为了研究地震作用下的塔线耦合作用,结合某220 kV输电线路工程,建立杆塔的单塔模型和三塔两跨的塔线耦联体系模型,并分别进行动力特性分析和地震时程响应分析,通过对比两个有限元模型的计算结果,发现:1)塔线耦联体系模型中杆塔频率小于单塔模型;2)低地震烈度下塔线耦联体系中杆塔地震响应高于单塔模型,而在高地震烈度下塔线耦联体系中杆塔地震响应出现低于单塔模型的情况;3)架空导线的质量效应使杆塔地震响应增大,同时架空导线可通过自身振动耗散一定的地震能量,这种非线性振动耗能减震效应随着地震动强度的增大而越发明显。

Electricity transmission lines consists of transmission tower structure and conductors as well as ground wires.Coupling effects of the system are prominent.In order to study the influence of transmission lines on transmission tower under earthquake actions,two finite element models were established based on a 220 kV transmission project,including a single tower model and a tower-line coupling model.Dynamic characteristics analysis and seismic time history analysis were carried out for the two models.By comparing the results of the two models,it can be found that the frequency of transmission tower in the tower-line coupling model was less than that of single tower model.Seismic responses of the transmission tower in the tower-line coupling model with low seismic intensity was higher than that of the single tower model,while the result could be the opposite with high seismic intensity.The mass of transmission lines would amplify the seismic responses of transmission tower,while the nonlinear vibration of them could also dissipate some seismic energy,thus reducing the seismic responses of transmission tower.The nonlinear energy dissipation effects would become more and more obvious with the increase of seismic input intensity.