Cyclonic resilience method developed off Texas power system

Based on a model of the Texas power system, scientists from the Potsdam Institute for Climate Impact Research PIK have developed a new method to identify and harden critical lines against tropical cyclones and increase power system resilience.

The scientists developed a model that simulates storm damages to the Texas power grid and studied 10,000 realisations of potential damages for each of seven historical tropical cyclones, including the major hurricanes Harvey (2017) and Ike (2008). Their approach allowed them to reproduce observed supply failures.

The Texas electric power system was chosen due to its high frequency of exposure to hurricanes and weaker tropical storms, providing the perfect context to study these complex effects and potential resilience adaptation options in depth.

The researchers, who published their findings in Increasing the resilience of the Texas power grid against extreme storms by hardening critical lines, find that large-scale power outages caused by tropical cyclones can be prevented almost entirely if small but critical sets of power lines are protected against storm damages.

Study author and PIK scientist Christian Otto commented in a release on their analysis: “We found that the failures of certain lines can trigger large-scale outages affecting whole regions or cities. Regions or cities fail in one major cascade, rather than gradually.

“Our research shows that such cascades can be avoided almost entirely if less than 1% of the overall grid – this is 20 lines in the case of the Texas power grid – is protected against storm damages, for example by reinforcing transmission towers or using underground cables. This way, the risk of outages in major population centres can be significantly reduced. Notably, protecting the same small set of relevant lines works for all seven historical hurricanes considered.”

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Modelling grid to storms

Based on a model of the Texas power grid, the scientists coupled a model of the evolution of tropical clones’ wind fields with a dynamic model of the Texas power grid in a spatio-temporal approach, allowing it to describe the evolution of storm-induced cascading power outages.

“For the first time, our analysis shows how an electric network reacts to evolving storms. By simulating the co-evolution of wind-induced failures of high-voltage transmission lines and the resulting cascading power outages, we discovered which parts of the electricity network are most critical as their failures have cascading impacts leading to major power outages,” said PIK scientist and study author Frank Hellmann.

“This appears to be a property of the network itself, rather than the storm’s precise path.”

“This is a challenging task, as the time scales at which storms and power outages evolve can be very different,” added scientist Mehrnaz Anvari, who conducted the research at PIK and is now group leader of Network Evaluation Technologies at the Fraunhofer Institute for Algorithms and Scientific Computing.

“By combining PIK expertise on the event-based modelling of tropical storms and power grids, we managed to identify the critical lines, whose failure can trigger large blackouts.”

“Tropical cyclones are one of the most destructive category of extreme weather events,” said Katja Frieler, scientist and head of the Research Department, Transformation Pathways, at PIK.

“As peak wind speeds of the most intense storms are projected to increase with global warming, the damage caused by these storms is likely to increase unless we adapt accordingly. Our new method gives grid operators a crucial tool to identify effective adaptation options and can help make our infrastructure networks fit for a new climate reality.”