Resilience of Transmission Line Structures to Extreme Weather Events

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The reliance of all infrastructure operation on electrical power has made electricity a vital component of modern life. Power disruptions during a hazard event can thus have devastating effects on safety, economic security, and public health. The proposed work will focus on the impact of extreme wind events on transmission line (TL) structures: the grid elements most vulnerable to wind hazards. In Canada and other countries, incidents involving the failure of those structures during extreme wind conditions are annual events, and the effects of climate change are exacerbating the frequency and intensity of their occurrence. The applicant's pioneer research led to the creation of the world's first specification that enables the effective design of new TL structures to resist tornadoes and downbursts (thunderstorm wind), which was incorporated into the 2020 American Society of Civil Engineers guidelines. However, the greatest challenge lies in assessing the structural behaviour of existing structures. The proposed work will involve developing and validating a state-of-the-art numerical model that will include the simultaneous simulation of the towers in a TL segment while considering the interaction that happens between the towers through the in-between conductors. The model will accurately predict the failure mode of a tower during a wind event, compute the dynamic forces induced on adjacent towers during the failure mechanism, simulate the collapse as it progresses from tower to tower, and forecast the extent of the cascading collapses. The model will incorporate synoptic dynamic wind loads determined from computational fluid dynamics (CFD) simulations of real conditions at the line area plus downburst and tornado loads. All components of this numerical model will be validated experimentally at the $30M WindEEE dome, the world's only three-dimensional wind chamber. This research will provide a breakthrough advance in knowledge related to TL structural behaviour under various types of extreme wind events and will produce highly beneficial tools for utility companies in particular and society in general. Upgrading an entire TL network is impossible. The developed tool will enable the most accurate assessment of the failure risk for individual network segments and will facilitate informed and cost-effective upgrade decisions based on the importance of the line, the level of redundancy, and the connectivity with other utilities. Since electricity forms the backbone of an urban system, the proposed studies represent a key milestone in achieving the applicant's long-term goal of creating tools for evaluating community resilience to weather-related hazards, taking into account the dependencies among infrastructure components. The studies will provide eight graduate students with training in state-of-the-art numerical and experimental techniques, while addressing a serious practical and pressing problem.