考虑台风非平稳性和竖向风影响的输电杆塔风荷载模型

There is an inconvenient vertical wind component in cloud wall zone. Furthermore, the wind speed of typhoon reveals a significant temporal trend. However, the traditional overhead transmission line wind load model only taken horizontal wind component into account, and wind was treated as a stationary-Gaussian stochastic process, so that the essential characteristics of typhoon can’t be reflected. Aims at setting up a transmission tower wind load model with consideration of non-stationary and vertical wind, some research contents are planned as follows. Firstly, ascertain typhoon wind field characteristics by the non-stationary sample, and contrast the characteristics reflected by non-stationary sample with the characteristics reflected by stationary sample. Then, under combined effect of horizontal and vertical wind, design a wind tunnel test method for the identifying of shape coefficient of transmission tower segment, and obtained three dimensional shape coefficient matrix depending on wind attack angle and yaw angle. Finally, in time domain, analyze the wind induced vibration response of transmission tower-line system with consideration of non-stationary and vertical wind, and estimate the reliability level of wind induced vibration response achieved by traditional analyzing method. The purpose of this project is to improve the calculation precision of transmission tower wind load under typhoon, moreover, a more realistic static and dynamic response results can be expected.

台风云墙区内存在着量值可观的竖向风速分量，且风速样本具有较强的非平稳性。但传统的架空输电线路风荷载模型仅考虑了水平风荷载的作用，且将脉动风作为平稳随机过程来处理，无法真实反映台风作用下杆塔风荷载的特异性。本项目拟建立考虑台风非平稳性和竖向风影响的杆塔风荷载模型，主要研究内容包括：基于非平稳样本确定的台风风场特性，对比分析其与平稳样本确定的风场特性之间存在的差异；设计水平与竖向风联合作用下杆塔节段体型系数识别风洞试验方法，获取依存于风偏角和风攻角的三维体型系数矩阵；在时域内实现考虑台风非平稳性和竖向风影响的塔线体系风振响应分析，评估非平稳性和竖向风计入与否，对响应计算结果的影响程度。本项目旨在提高台风荷载作用下输电杆塔风荷载的计算精度，以得到更为真实的杆塔静动力响应计算结果。

台风云强区内存在着量值可观的竖向风速分量，且风速样本具有较强的非平稳性。但传统的架空输电线路风荷载模型仅考虑了水平风荷载的作用，且将脉动风作为平稳随机过程来处理，无法真实反映台风作用下杆塔风荷载的特性。本项目通过分析实测台风苏力的风速数据，并借助风洞试验，针对上述问题开展的研究工作主要包括：.①采用游程检验法对台风苏力风速样本的平稳性进行了评估；.②对没有通过游程检验的，采用10s间隔短样本取平均值，分离了非平稳平均风速；.③对去除时变平均风后的脉动风速时程，以600s为采样间隔，分析了样本随EMD分解次数的平稳性。.④设计制作了可调风偏角在0～360度范围，可调风攻角在-90～90度范围之间的测力试验支架。.⑤在ANSYS中建立了3个依存于风攻角和风偏角的三维table数组，分别用于存储试验测得的铁塔节段横线向力系数、顺线向力系数和竖向力系数，可实现任意攻角和任意偏角下铁塔节段横向、顺向和竖向节点力的插值生成。.⑥在时域内实现了考虑台风非平稳性和竖向风影响的输电杆塔风荷载模型，比较了考虑台风非平稳性与否、考虑竖向风与否对输电线路铁塔塔脚剪力、弯矩、导地线跨中位移的影响趋势和影响幅度。.研究表明，台风非平稳性对输电铁塔安全性能有一定的影响，需要建立统一的台风荷载计算方法，以便更准确的评价非平稳性对输电铁塔安全性能的影响程度；台风竖向风速分量导致导线跨中横向、竖向位移影响量值分别增大2%和7%，考虑相间振动非同步性可能导致相间安全距离缩小4%和14%，沿海台风多发地区有必要在进行电气间隙圆设计时予以考虑。