EPCN: Quantifying the Resilience of Power Systems to Natural Disasters

University Of Washington, Seattle WA

Investigators

Abstract

Power systems are not likely to remain unscathed by natural disasters such as hurricanes, earthquakes, ice storms or floods. Power outages lasting days or even weeks might ensue and will affect not only the well-being and the economy of the affected communities but could also threaten their very fabric. Recent events, such as Super-storm Sandy and hurricane Katrina, have highlighted the need to improve the resilience of the electricity grid. Some utility companies, such as Consolidated Edison, have embarked on massive investment programs aimed at hardening parts of their network. The design changes that these companies are implementing are based on observations of which components failed during past disasters. While such measures will undoubtedly be useful, they tend to focus on the resilience of individual components but do not necessarily represent the most effective way to enhance the resilience of the system. Large infrastructure investments may therefore not be targeted at the most effective solutions. To overcome this problem, electric utilities and government agencies in all areas that could be affected by a natural disaster need a rigorous method for assessing the relative value of various investments. This proposal describes how the overall resilience of a power system could be quantified. It also outlines a technique to assess the relative value of measures aimed at hardening various components or facilitating the repair and restoration of the system. Quantifying the resilience of a power system turns out to require the solution of a very complex optimization problem. New optimization algorithms will be needed to solve this problem and hence to answer the pressing practical issue that this project addresses. This project will produce advances in two directions: 1. The development of quantifiable models of the power system repair and restoration process following a natural disaster. These models will support the optimization of investments aimed at improving the resilience of the power system. 2. The quantification of the resilience of a power system to natural disasters involves the solution of a new type of multistage optimization problem where the cost function depends on the cumulative time required to reach each node in a graph. As illustrated in the proposal, this can lead to counterintuitive optimal recovery schedules. For example repairing first the branches connecting to nodes with the largest number of consumers may not constitute the optimal strategy. The availability of a technique to quantify the resilience of a power system to natural disasters will help electric utilities decide how best to direct the vast sums of money required to improve this resilience. It will also be useful to governments and regulatory agencies when they consider how much money should be spent on power system resilience as opposed to other priorities. Emergency management agencies could also use these models and tools to study the interdependencies between the electricity grid and other critical infrastructures, with the aim of better coordinating the post-disaster recovery process. The ultimate beneficiaries of this project will be the people and communities affected by a natural disaster because its results should help reduce the human suffering and the economic hardships that they are bound to suffer. Since this research topic is apt to capture the imagination of young people, the investigators will organize related undergraduate research projects for students from underrepresented minorities at one of the participating institutions. They will also discuss resilience issues at a symposium on energy-related technologies for high school and community college students.