Direct synthesis-based optimal PIDD2 controller design for enhanced load frequency control in electrical power systems

Abstract

The increasing load demand in power system (PS) networks necessitates the improvement of system stability and the preservation of the reliability of electrical power systems (EPS). This case is critical for ensuring energy supply security and maintaining sustainable system performance. Specifically, sudden load changes cause deviations in frequency and tie-line power values from their nominal levels in interconnected power systems (IPS), making load frequency control (LFC) an essential requirement. This research presents a Proportional-Integral-Derivative plus Second Order Derivative (PIDD2 ) controller design for LFC in IPS, tuned using the Direct Synthesis Method (DSM). The design is developed for single, and two-area PS, encompassing both reheated and non-reheated thermal turbine models. In the proposed design method, controllers are designed for disturbance rejection. The controller parameters were obtained using a novel objective function that includes the settling time and Integral of Absolute Error (IAE). The results demonstrate that the proposed design surpasses the compared methods in terms of frequency and tie-line power deviations, and the robustness of the system is validated through testing under ±25% parameter variations. © 2025 Elsevier B.V., All rights reserved.