Operational risk assessment of electric power grids exposed to straight-line winds

Weather-related events are the most dominant cause of power grid failures. In addition, climate change is expected to increase the frequency and intensity of extreme weather events and thus increase the risk to the aging power grids worldwide. The current state-of-the-art lacks approaches that perform an integrated grid assessment that spans from a component-level to a full-scale system security analysis. In this work, we propose a framework to assess the probability of transmission line outages due to straight-line winds in a selected region and to quantify their impact on power system security. The framework provides an end-to-end approach that comprises of i) an assessment of the grid exposure to regional wind profiles, ii) power line segment-level fragility analyses representing physical vulnerabilities, iii) power line outage probability estimation, and iv) n-k system security analyses. Overall, the approach allows us to quantify the country-level impact of straight-line winds on the power grid. We exemplify the approach on the power grid of Switzerland, where windstorms are one of the main factors for line outages. The results show a non-negligible difference in the risk of cascading failures when considering the wind effects compared to when we do not.