Simulation and Performance Analysis of a Synchronous Generator Excitation System: Case of the IEEE ST1A

This paper presents a simulation-based performance analysis of the IEEE ST1A static excitation system for a synchronous generator. This system plays a crucial role in ensuring optimal generator operation by regulating the output voltage and maintaining network stability under disturbances. The main objective is to evaluate the stability, speed, accuracy, and damping characteristics of the voltage regulator. The methodology is based on MATLAB/SIMULINK simulations, enabling a detailed analysis of the ST1A model's dynamic behavior under various fault conditions, including single-phase, two-phase, and three-phase faults within an IEEE 9-bus network. The results show that the ST1A system provides fast and precise voltage regulation, minimizing oscillations and enhancing overall system robustness. However, its ability to damp low-frequency electromechanical oscillations is limited. The integration of a multi-band Power System Stabilizer (PSS4B) proves essential to significantly improve damping, reduce settling times, and enhance transient stability. The coordinated ST1A–PSS4B configuration thus represents an effective solution for reliable voltage control and stability enhancement.