Analysis and Control of Frequency Stability in Low-Inertia Power Systems: A Review

Power electronic-interfaced renewable energy sources (RES) exhibit lower inertia compared to traditional synchronous generators. The large-scale integration of RES has led to a significant reduction in system inertia, posing significant challenges for maintaining frequency stability in future power systems. This issue has garnered considerable attention in recent years. However, the existing research has not yet achieved a comprehensive understanding of system inertia and frequency stability in the context of low-inertia systems. To this end, this paper provides a comprehensive review of the definition, modeling, analysis, evaluation, and control for frequency stability. It commences with an exploration of inertia and frequency characteristics in low-inertia systems, followed by a novel definition of frequency stability. A summary of frequency stability modeling, analysis, and evaluation methods is then provided, along with their respective applicability in various scenarios. Additionally, the two critical factors of frequency control-energy sources at the system level and control strategies at the device level-are examined. Finally, an outlook on future research in low-inertia power systems is discussed.