Multi-objective Coordinated Optimization of PSS and FACTS-POD Controllers based on EWOA to Improve the Stability of wind-PV Hybrid System

Introduction: The integration of wind and photovoltaic power generation significantly impacts system stability, necessitating a coordinated design approach between Power System Stabilizers (PSS) and Flexible AC Transmission System (FACTS) devices to effectively mitigate Low-Frequency Oscillations (LFO) in hybrid power systems. Method: This study presents a comprehensive optimization strategy that coordinates PSS with additional power oscillation damping controllers for both Static Var Compensator (SVC-POD) and Thyristor Controlled Series Capacitor (TCSC-POD). The proposed multi-objective function incorporates critical stability indicators, including generator rotor speed deviation, eigenvalue real components, damping ratios associated with low-frequency oscillation modes, and system bus voltage deviations. To optimize the controller parameters, an Enhanced Whale Optimization Algorithm (EWOA) is implemented. Results: The effectiveness of this optimization strategy is validated through eigenvalue analysis and time-domain simulations conducted on the IEEE 4-machine 2-area test system under various operating conditions. Discussion: The proposed EWOA-based coordinated control effectively suppresses low-frequency oscillations while improving voltage stability in renewable-integrated power systems. Although validated on a standard test system, the approach shows promising potential for real-world applications. This work advances damping control strategies for modern power grids with high levels of renewable energy penetration. Conclusion: Simulation outcomes verify that the EWOA-optimized controller parameters substantially improve system stability, effectively attenuate low-frequency oscillations, and improve voltage regulation capabilities.