A robust PID-based power system stabilizer for damping low-frequency oscillations in a single machine infinite bus system

Abstract

This paper proposes a robust PID-based power system stabilizer (PID-PSS) for damping low-frequency oscillations in a Single Machine
Infinite Bus (SMIB) system. The controller is developed from the linearized Heffron-Phillips model and uses a washout-assisted PID structure to enhance the damping torque associated with rotor-speed deviations. Controller parameters are selected using an eigenvalue-based objective function together with a damping-ratio constraint and transient-performance criterion. The proposed method is evaluated against AVR-only operation and a conventional Lead-Lag PSS through eigenvalue analysis and time-domain simulation. The simulation results show that the PID-PSS improves damping ratio, reduces overshoot, shortens settling time, and decreases electrical-power and voltage ripple over a range of operating conditions. To verify practical applicability, the controller is implemented on an external digital AVR/PSS platform at Ban Ve Hydropower Plant and tested according to EVN Circular 25 procedures. The experimental results confirm that the proposed PID-PSS achieves stronger damping and faster oscillation suppression than the existing stabilizer, demonstrating its effectiveness for practical power-plant operation.