Rotor Angle Stability Analysis of Hybrid Wind Energy Source Integrated with Conventional Grid

Abstract

This paper investigates the design and optimization of a Power System Stabilizer (PSS) to enhance rotor angle stability in a hybrid wind energy system integrated with a conventional grid (single machine infinite bus) under a 50% step disturbance in mechanical torque (Tm). Low damping torque, extended electromechanical oscillations, and rotor instability were the outcomes of the disturbance's torque mismatch between the mechanical input and electrical output. In order to optimize damping performance, the PSS parameters were ideally tuned using the Artificial Ecosystem Based Optimization (AEO) and Secretary Bird Optimization (SBO) algorithms. MATLAB/Simulink 2023a was used to model and simulate the hybrid system, which consists of SMIB, Doubly-Fed Induction Generator (DFIG), and Permanent Magnet Synchronous Generator (PMSG) wind farms. Without a PSS, the system exhibited poor damping with rotor speed deviation and actual rotor speed and system rotor angle settling times of 9.98 s, 8.61 s, and 9.41 s, respectively. The AEO-PSS reduced these to 3.49 s, 2.98 s, and 3.59 s, while the SBO-PSS achieved superior responses of 1.99 s, 2.20 s, and 2.21 s. In the hybrid wind-integrated configuration, the SBO-PSS achieved a rotor speed deviation settling time of 2.20 s, outperforming AEO-PSS at 2.51 s. Eigenvalue analysis confirmed enhanced damping ratio. The optimized SBO-PSS effectively mitigated these effects, improving synchronizing torque and shifting system poles deeper into the left half-plane to ensure stable and robust operation. The 50% Tm torque disturbance, low excitation damping torque, and inertia from wind integration were the main causes of the instability; however, the optimized controller successfully reduced these effects by enhancing synchronizing torque and moving system poles deeper into the left half-plane to guarantee stable and reliable operation.