Structural Response of Power Transmission Line Towers to Extreme Wind Events- A Critical Review

Abstract

Transmission line towers are lifelines of modern power grids, yet their vulnerability to extreme and non synoptic wind events - downbursts, tornadoes, hurricanes, and combined multi-hazard conditions - remains poorly addressed in current design practice. This review synthesizes findings from experimental testing, finite element modelling, computational fluid dynamics, probabilistic fragility analysis, machine learning surrogates, and a patent survey spanning 1990–2025, to critically assess where knowledge stands and where standards fall short. Quasi-static design codes consistently underestimate peak demand: downburst dynamic amplification factors reach 3.5, maximum skewed wind loading occurs at 30° rather than the code-assumed 45°, and sandstorm conditions alone inflate structural demand by up to 25.6%. Structurally, collapse initiates at compressed members below the lower cross-arm through bidirectional instability - a failure mode that geometric imperfections can trigger even in code-compliant towers. Foundation flexibility, tower-line coupling, and multi-hazard loading introduce further demand that no current standard explicitly captures. Patent filings have grown sharply since 2010 - yet the gaps are striking. Downburst load methods, tornado-resilient geometries, probabilistic fragility tools, and interoperable digital twin standards all remain absent from the IP landscape. Five targeted code modifications are proposed, alongside a tiered site-specific hazard assessment framework. Priority research needs include full-scale non-synoptic wind measurements, coupled system modelling, and reliability-based design approaches tailored to regional hazard profiles.