Title: Next-Generation Power System Strength Metrics: Quantification, Equivalents, and Applications

Program: Electrical and Computer Engineering PhD

Committee Chair: Eklas Hossain

Committee: Eklas Hossain, Kurtis Cantley, Said Ahmed-Zaid, Andres Valdepena Delgado

Abstract: The electric power industry worldwide shares a common goal of achieving clean energy in both short- and long-term planning as a unified response to climate change. This goal is being pursued through an increasing integration of non-carbon-emitting generation and renewable energy sources. The transition from conventional generation to this evolving energy mix, combined with the emergence of complex loads such as data centers and electric vehicles, defines the new power system.

The underlying physics of this new power system differs significantly from that of conventional systems dominated by large rotating generators. As a result, maintaining reliable and clean power requires a renewed understanding of system behavior and performance.

This thesis focuses on the technical aspects of power system strength within the new power system paradigm. First, the quantification of system strength is revisited. A next generation of empirical system strength metrics is then developed, led by the Dynamic Grid Strength Index (DGSI), which addresses limitations of existing steady-state, time-domain, and frequency-domain characterizations. Building on this, a modified DGSI (mDGSI) is proposed to incorporate the effects and interactions of hybrid grid-following and grid-forming inverter-based systems. In addition, a clustering-based framework is introduced to determine equivalent strength metrics across different domains.

In the second part of the thesis, these next-generation strength metrics are applied to key power system studies relevant to system planners, including energy storage siting and the identification of unique credible contingencies.