TY - JOUR TI - Joint optimization of system hardening and restoration for resilience enhancement against cascading failures DO - https://doi.org/doi:10.7282/t3-3rsq-zv71 PY - 2020 AB - This dissertation presents a framework that determines the optimal integrated system hardening and system restoration strategies. The objective is to improve system resilience while minimizing total cost including investment cost and system damage cost in the event of system failure propagation. The successful functioning of modern society is increasingly dependent upon various crucial infrastructure systems, such as power grids and communication systems, which all comprise a large collection of interconnected sub-systems. The reliability and resilience of these network systems becomes a matter of great concern due to the inevitable occurrence of system failures and their probable disastrous aftereffects. Although it is uncommon for many applications, there are still many examples of massive cascading failures in various real-world network systems. In this research, the mechanism of cascading failures in network systems is investigated, taking into account practical network load dynamics as well as multiple dependencies between and inside systems. A new resilience metric which can be used to evaluate system resiliency loss caused by system disruptions is proposed. Then focusing on electricity system, the influence of cascading failures in power generation and transmission system is extended to local power distribution systems to analyze the resilience of the entire electrical power system. System hardening strategies and system restoration strategies are jointly optimized with the consideration of the existing interaction between each other. The effects of installing distributed energy resources to end users in electricity system, for instance solar array and battery storage, as a type of system hardening measure to improve electric power system resilience are investigated. The effectiveness of restoration strategies with different restoration prioritizations on reducing the influence of cascading failures on resilience is explored. Finally, an approach to relate the improved system resilience to the reduction in economic losses is developed. Optimization methods are proposed to achieve a balance between the investment of resilience enhancement driven actions, such as system hardening planning and restoration decisions, and system damage cost, for example, unsatisfied customer demand cost. As a result, system resilience targets are better integrated into the investment of resilience enhancement measures. The proposed methodology can be utilized as a decision-making tool for future resilient network systems, for example, electric power system, design and restoration. Together, this research is useful to mitigate and rescue the system from the next cascading failures with the application of effectively integrated system hardening and restoration strategies for resilience enhancement with minimized total cost. KW - Cascading failures KW - Industrial and Systems Engineering LA - English ER -