纵向地震下1000kV出线构架的输电导线耦合作用振动台试验研究

Shaking table test on 1000kV frame by considering coupling effect of transmission lines under longitudinal excitations

为研究纵向地震作用下输电导线的动力耦合作用对1000kV出线构架地震响应的影响机理并讨论不同输电导线垂跨比的影响,开展了缩尺比为1∶15的考虑输电导线动力耦合作用的单跨1000kV出线构架振动台试验研究,其中输电导线采用基于等效动力刚度的无质量弹簧模拟。试验采用人工质量相似模型并使用原材料,设计、加工了高精度的构架试验模型和输电导线等效试验模型,选取20条真实地震记录对试验模型进行纵向激励并采用白噪声记录进行扫频分析以检测结构的完好性。结合试验现象对比分析考虑与不考虑输电导线动力耦合作用的两类模型的结构响应,分析发现:输电导线与构架的动力耦合作用较强,削弱了构架的地震响应;随着垂跨比的减小,被悬挂系统耗散的能量增大,输电导线对构架的弹性约束增强,构架的地震响应进一步被削弱。此外,对试验模型进行数值重现分析,发现试验与数值所得的位移时程曲线拟合较好,结构最大位移误差较小,说明有限元方法可以较好地模拟输电导线的动力耦合作用。

To figure out the influence mechanism of the dynamic coupling effect of transmission lines on seismic responses of the 1000 kV outgoing line frame under longitudinal excitations and discuss the influence of sag-span ratios of transmission lines, shaking table tests were performed on a single-span 1000 kV outgoing line frame by considering the dynamic coupling effect of transmission lines with a scale factor of 1∶15.Moreover, transmission lines were simulated by the massless springs with equivalent dynamic stiffness.Test results indicate that the seismic responses of 1000 kV frame are reduced by the strong dynamic coupling effect of transmission lines;with the decrease in sag-span ratio, the energy dissipated by the suspended system increases and the elastic constraints of transmission lines on the frame enhance,resulting in further reducing the seismic responses of 1000 kV frame.Furthermore, the results of numerical reconstruction analysis of the experiments indicate that the finite element analysis can simulate the dynamic coupling effect between transmission lines and 1000 kV frame very well.