Behaviour and design procedures for transmission towers under high intensity wind loads

包括龙卷风和下击暴流在内的高强度风(HIW)是全球80%以上与天气有关的输电线路故障的原因。尽管如此，输电线路的设计规范是基于与大范围事件相关的传统风廓线。HIW具有不同的剖面，这影响了风荷载在铁塔和线路上的分布。UWO与马尼托巴省水电(MH)和其他公用事业公司合作开展了一项研究计划。开发了一种用于预测输电线路对HIW响应的数值工具。它结合了从计算流体力学分析中获得的模拟HIW的风场。对该数值模式的各个组成部分分别进行了验证。研究表明，位于塔楼不同区域的结构构件可能具有特定的关键HIW特征，这些特征由事件的大小和位置定义，从而导致这些构件的最大受力。在本研究中，将对输电线路系统的风速和振动进行连续监测。结果将提供更多关于HIW领域和塔楼对这些事件的反应的洞察力。它们也将被用来验证整个数值模式。将对具有各种结构配置的许多传输线系统进行数值建模。结果将被用来提出一组设计荷载工况，模拟各种结构系统的临界高强度荷载工况的包络。数值模型中将包含输电线路各部件的准确失效模型。这将使研究在高强度焊接期间塔楼的逐步倒塌成为可能。这一扩展模型与现有的HIW气候数据一起，将导致开发一种设计程序，其中将包括建议的风速和设计载荷情况。设计程序将确保输电线路在中等HIW期间不受损坏，同时防止在强HIW期间完全坍塌。这将有助于减轻与高强度焊接期间输电线路故障相关的经济和社会损失。三名博士和两名理学硕士。学生将参与到这个提案中来。

High Intensity Winds (HIW), which include tornadoes and downbursts, are responsible for more than 80% of all the world's weather-related transmission line failures. Despite this fact, the codes of design for transmission lines are based on a conventional wind profile associated with large scale events. HIW have different profiles, which impact the distribution of wind loads over the towers and lines. A research program was conducted at UWO in collaboration with Manitoba Hydro (MH) and other utility companies. A numerical tool was developed to predict the response of transmission lines to HIW. It incorporates wind field simulating HIW obtained from a computational fluid dynamic analysis. Various components of this numerical model were validated separately. The study revealed that structure members located at various regions of a tower can have specific critical HIW characteristics, defined by the size and location of the event, that lead to maximum forces in these members. In the current study, continuous monitoring for the wind velocity and the vibrations of a transmission line system will be conducted. The results will provide more insight about the HIW fields and the response of the towers to those events. They will also be used to validate the entire numerical model. A number of transmission line systems, having various structural configurations, will be numerically modeled. The results will be used to propose a set of design load cases simulating an envelope for the critical HIW cases for various structural systems. An accurate failure model for various components of the transmission lines will be incorporated into the numerical model. This will allow studying the progressive collapse of the towers during HIW. This extended model, together with available climate data for HIW, will lead to the development of a design procedure that will include recommended wind speeds and design load cases. The design procedure will ensure that transmission lines remain undamaged during moderate HIW, while preventing a total collapse during strong HIW. This will help in mitigating the economical and social losses associated with the failures of transmission lines during HIW. Three Ph.D. and two M.Sc. students will be involved in this proposal.