PSO-Optimized IT2FLC for load frequency and VRFB control in two-area interconnected power system
Mohammed Hamouda Ali, Mostafa Bahaa, Mohammed Mehanna
Abstract
The integration of large-scale renewable energy sources into power systems poses significant challenges for load frequency control (LFC) due to variability and unpredictability. Additionally, sudden demand fluctuations further complicate LFC in modern power systems. This study proposes a novel Interval Type-2 Fuzzy Logic Controller (IT2FLC) to address these challenges. The IT2FLC is applied to a two-area power system with solar parks and Vanadium redox flow batteries (VRFBs) to act as LFC, where the IT2FLC is also utilized to adaptively control the VRFB gains, enabling real-time adjustments to enhance the dynamic performance of the power system. The gains of both the LFC and adaptive VRFB controllers are then optimized using particle swarm optimization (PSO) with the Integral Time-Squared Error (ITSE) cost function. Compared to IT2FLC with constant VRFB gain and T1FLC, the proposed controller reduced settling time by 20%, improved steady-state error by over 50%, and minimized overshoot and undershoot by approximately 30%. The 95% confidence interval (CI) analysis further validated its robustness by demonstrating lower performance variability. These findings highlight the effectiveness of adaptive IT2FLC with VRFB gain control in improving LFC performance for renewable-rich power systems, offering a promising solution for enhancing frequency stability in modern grids.