Transient Stability Enhancement of Single-Machine Infinite Bus System Using Hybrid PSS Design with Particle Swarm Optimization

Power system stability is critical for reliable grid operation. This paper presents a two-stage hybrid design method for Power System Stabilizers (PSS) to improve transient stability in Single-Machine Infinite Bus (SMIB) systems. The first stage uses analytical phase compensation to design an initial PSS that ensures system stability. The second stage applies Particle Swarm Optimization (PSO) to fine-tune the PSS parameters for optimal performance. The method was tested on a 900 MVA generator system under severe fault conditions. Results show that the optimized PSS reduces settling time by 9.83% and decreases the Integral of Time-weighted Absolute Error (ITAE) by 47.98% compared to the analytical design. The hybrid approach combines the reliability of classical control theory with the performance benefits of modern optimization, making it suitable for practical power system applications.Index Terms—particle swarm optimization, phase compen- sation, power system stabilizer, single-machine infinite bus, transient stability