海岛大跨越输电塔线体系风振响应及动力失稳分析

Analysis of Wind Vibration Response and Dynamic Instability of Large Crossing Transmission Tower Line System Between Islands

跨海输电塔线体系具有铁塔高、跨度大、风速大、恢复困难等特点,是岛屿电网的关键薄弱位置,尤其受台风等灾害天气影响严重,为进一步认识跨海输电塔线体系的风振响应特点和强风作用下的铁塔风致失稳特征,以温州洞头某线路典型跨海段(耐—直—直—耐)线路为研究对象,采用ABAQUS软件建立该跨海段两塔三线有限元分析模型。首先分析导线、裸塔及塔线体系的动力特性参数,然后开展不同风向角下的风振响应分析及位移风振系数计算,最后,采用增量动力分析方法(incrementaldynamicanalysis,IDA)模拟强风作用下考虑塔线耦合效应的铁塔非线性倒塌过程。研究表明:大跨越导线、地线对输电塔在不同风向角下的风振响应影响存在差异,0°风向角下,大跨越导线、地线增大体系的阻尼,降低风振响应;90°风向角下,大跨越导线、地线在横向风作用下产生较大面外位移,增大塔线体系的风振响应;强风作用下,输电塔斜材相较于主材更容易发生动力失稳,引起结构内力重分布,使得塔身中上部受力集中,最终导致输电塔发生渐进式倒塌。

The cross sea transmission tower system has the characteristics of high tower height,large span,high wind speed,and difficult recovery,making it a key weak point in the island power grid,especially severely affected by disasters such as typhoons and strong typhoons.In order to further understand the wind vibration response characteristics of the cross-sea power transmission tower line system and the tower wind destabilization characteristics under the action of strong winds,to a line in Dongtou,Wenzhou,a line of the typical cross-sea section(resistant-straight-straight-resistant)line was taken as the research object.The ABAQUS software was used to establish a finite element analysis model of two towers and three lines in this cross sea section.Firstly,the vibration modes and dynamic parameters of the tower and wire system,the ground wire,the bare tower and the tower system were analyzed.Then,the wind vibration response analysis and displacement wind vibration coefficients of the bare tower and the tower system under the wind angles of 0°and 90°were carried out.Moreover,the incremental dynamics analysis(IDA)was used to simulate the tower wind destabilization characteristics and wind vibration coefficients of the towers under strong winds,taking into account the coupling effect of the ground wire.Finally,IDA was used to simulate the nonlinear collapse process of the tower under strong wind considering the coupling effect of the guide wire.The study shows that there are differences in the influence of the large spanning guide wire on the wind vibration response of the transmission tower under different wind angles.Under 0°wind angle,the large spanning guide wire increases the damping of the system and reduces the wind vibration response,and under 90°wind angle,the large spanning guide wire produces a larger out-of-plane displacement under the action of the transverse wind,which increases the wind vibration response of the tower and wire system.Under strong wind,the diagonal steel of the tower is relatively strong compared to the diagonal steel of the tower,and the displacement and wind vibration coefficient are also different.Under strong winds,the inclined material of the transmission tower is more prone to dynamic instability than the main material,which causes the redistribution of structural internal forces,resulting in the concentration of forces in the middle and upper parts of the tower,and ultimately leading to the gradual collapse of the transmission tower.