Stability Analysis of Modern Electrical Power Systems

The increasing integration of renewable energy sources, distributed generation, energy storage systems, and flexible loads is significantly transforming the dynamic characteristics of modern electrical power systems. These developments introduce new challenges to power-system stability, including reduced system inertia, complex control interactions, voltage instability, frequency deviations, and oscillatory behaviour. This review paper presents a comprehensive overview of stability analysis techniques applicable to modern electrical power systems, covering rotor-angle stability, frequency stability, voltage stability, and converter-driven stability. Classical analytical approaches, including eigenvalue analysis, small-signal stability analysis, transient stability assessment, and time-domain simulation, are reviewed alongside emerging methods based on wide-area measurements, advanced control techniques, optimization, and artificial intelligence. Particular attention is given to the impact of inverter-based renewable generation and grid-forming and grid-following converter controls on system stability. The paper also discusses recent trends, computational challenges, and the applicability of data-driven and real-time stability assessment methods. Finally, key research gaps and future directions are identified to support the development of reliable, resilient, and flexible power grids capable of accommodating high levels of renewable and distributed energy resources.