Proposal of General Fragility Curve Variables for Korean Transmission Towers on Wind Load

With the increasing frequency and intensity of extreme weather events driven by climate change, damage to power grids caused by typhoons and hurricanes accompanied by strong winds has been escalating worldwide. Consequently, assessing the wind-resistant safety of transmission towers, which are key components of the power grid, has become increasingly important. However, conducting fragility analysis for individual towers across an entire power grid presents substantial practical challenges due to significant time and cost constraints. To overcome this limitation, this study proposes fragility curve parameters that can be broadly applied to various transmission tower configurations and employed in power grid safety assessments. For this purpose, nonlinear static pushover analyses were performed on transmission tower models representing the standard 154 kV, 345 kV, and 765 kV configurations used in Korea, and the corresponding load–displacement capacity curves were derived. Based on these results, the median failure wind speed (Vm) and logarithmic standard deviation (β) were calculated for each voltage class and for an integrated model. These values were then used to develop generally applicable fragility curve parameters for transmission towers subjected to strong winds. The proposed parameters are expected to serve as an efficient and reliable tool for probabilistic safety evaluations of power grids and risk assessments under extreme wind events.