单回路500kV输电塔风致响应参数分析

Parametric Analysis of Wind-Induced Responses of Typical 500 kV Single-Circuit Transmission Tower

首先,对典型单回路500kV高压输电塔进行了有限元模态分析;然后,利用基于非定常风荷载的风致动力响应频域分析方法,对单回路高压输电塔风致响应进行了参数分析;最后,详细探讨了参振模态数目、模态交叉项、结构阻尼比等参数对响应的影响。结果表明:输电塔上部节点考虑前三阶整体振型(两水平向侧弯和扭转)就能保证足够高的位移计算精度;参振模态数目对加速度响应值有较大的影响,随模态阶数的增加,加速度响应单调增大;基底弯矩主要由各方向一阶侧弯振型贡献。输电塔对阻尼比的变化敏感,随着阻尼比的增大共振响应明显减小,阻尼比对响应低频部分的影响基本可以忽略。此外,在单回路酒杯型输电塔频域响应分析中,可不考虑模态交叉项的影响。

The finite element modal analysis of a typical single-circuit 500 kV high-voltage transmission tower is carried out.Then,the computing method based on the non-steady wind forces in frequency domain is applied to the wind-induced responses calculation of the transmission tower,the effects of main frequency domain parameters such as number of modes numbers,cross terms of modes and damping ratio of structures on the response are discussed in detail.The results show that for the superstructure of tower,the calculation accuracy of displacement response can be ensured only by taking into account the bending(x 1 direction)and torsional(z direction)first order integral mode shape.And the mode numbers have great influence to the calculation of acceleration responses,the accelerations of transmission tower are monotonously increasing with the mode numbers.And the contribution for base bending moments mainly comes from the first bending mode.Furthermore,t he wind-induced responses of transmission tower are sensitive to the structural damping ratio,especially,the resonant responses obviously decreased with the increasing of damping ratio,but the change of damping ratio has little influence on low frequency part of responses.What is more,the cross terms of modes can be neglected for the responses calculation of typical single-circuit transmission tower in frequency domain.