PO-optimized cascaded FOIAN-PTD strategy for frequency control of wind-PV-thermal power system with energy storage systems

In today's evolving energy landscape, hybrid power systems integrating renewable and conventional sources are increasingly adopted to enhance sustainability. However, maintaining frequency stability remains a challenge due to the intermittent and unpredictable nature of renewable energy sources (RESs). This study presents a robust control strategy to enhance frequency regulation in a wind–solar–thermal hybrid grid using an advanced load frequency control (LFC) scheme. The proposed approach combines a novel fractional-order controller, termed fractional order integral accelerated with low-pass filter (N)-proportional tilt derivative (FOIAN-PTD), with coordinated capacitive energy storage (CES) and superconducting magnetic energy storage (SMES) systems. The FOIAN-PTD controller is fine tuned using the newly developed puma optimizer (PO), which outperforms existing algorithms such as GWO, ALO, AOA, ASO, QIO, and WOA in both convergence speed and control performance. Extensive simulations validate the superiority of the proposed method. The FOIAN-PTD controller achieves up to 89.3% improvement in overshoot and 88.9% in undershoot for frequency deviation in area-1 (Δf₁), 90.7% and 84.3% improvement for area-2 (Δf₂), and 95.1% and 90.6% improvement in tie-line power deviation (ΔP_tie), respectively, when compared with traditional PID and recent FO controllers. Moreover, the CES integrated with FOIAN-PTD significantly outperforms SMES in dynamic response, further enhancing grid reliability under varying renewable penetration scenarios. Overall, this research provides a scalable and high-performance LFC framework for modern hybrid power grid, offering enhanced frequency stability and resilience.