Resilience vs. reliability metrics in power systems

Power systems are intricately designed to deliver electricity to customers in a cost-effective and dependable manner. The reliability of the electricity system is reinforced through regulatory frameworks, incentives for compliance, and established quantitative measures. However, the occurrence of extreme events such as hurricanes, tornadoes, floods, earthquakes, cyberattacks, and various other challenges is becoming increasingly prevalent. The occurrence of large-scale power outages and the realization that routine reliability evaluations fail to account for the sustainability and robustness of power systems have raised concerns regarding implicit financial losses. Consequently, system planners, operators, and policymakers have recognized the significance of system resilience. However, the evaluation of power system resilience is a relatively new concept, lacking widely accepted standards, methodologies, or metrics for assessment. To address this gap, Resilience Metrics or indicators that gauge the adaptability of a power system have been employed for cost-benefit analysis in planning and operations. These adaptability metrics serve various purposes in different scenarios. For instance, understanding the impact of adaptability on economic losses resulting from disasters may be crucial for public or indigenous stakeholders. On the other hand, a refinery operator might prioritize knowledge about available spare corridors in stock and backup power generation options. This chapter aims to provide an introductory overview of resilience metrics, highlighting their distinctions from other core concepts such as reliability in power systems.