Single-Phase Sliding Mode Control Design for Terminal Voltage and Load Frequency Control of Power Systems

Abstract

The increasing complexity of power systems places high demands on maintaining frequency stability and generator terminal voltage. Variations in operating conditions can degrade power quality while affecting operational reliability and safety. Therefore, coordinated control between load frequency control (LFC) and automatic voltage regulator (AVR) is considered a key approach to enhancing the system’s performance. For the first time, the single-phase sliding mode controller (SPSMC) is developed for the LFC-AVR model of a hydroelectric power plant, enabling the system to achieve the sliding mode from the initial time t = 0, thereby enhancing overall stability. The proposed method aims to improve response quality and robustness against disturbances compared to advanced controllers. The system’s performance is evaluated against the grey wolf optimizer-proportional integral derivative (GWO-PID), moth flame optimization-PID (MFO-PID), and fractional-order PID (FOPID) controllers to highlight the improvement in dynamic response. Results demonstrate that the SPSMC achieves the smallest frequency deviation of 0.098 Hz. Furthermore, under parameter variations combined with a 5% load variation, the controller ensures robust performance, with the frequency dropping to only 49.51 Hz. These findings indicate that the proposed controller is a promising solution for improving the dynamic performance of hydropower-based LFC-AVR systems, with faster response and reduced oscillations.