A Moth Flame–Pattern Search Optimized Fuzzy PIDN Controller for Load Frequency Control of a Two-Area Deregulated Power System

Abstract

Deregulated power systems face the difficulty of load frequency control due to different transaction situations and system uncertainties. This paper assesses a Fuzzy PIDN controller that is being tuned via a Moth Flame-Pattern Search (MFO-PS) algorithm to a two-area thermal-gas system under Poolco, bilateral and contract violation conditions. It is hypothesized that the proposed controller has better dynamic performance when compared to GA-PID, DE-PID, TLBO-PID, TLBO-TID, and TLBO-PS:TID. It is done with a MATLAB/Simulink model and the performance is evaluated through settling time, peak deviations, and an integral square error (ISE). Results confirm consistent improvement. In the Poolco case, the proposed controller achieves settling times of 4.07 s (ΔF1), 1.83 s (ΔF2), 1.32 s (ΔPTie) with ISE = 0.0135, outperforming TLBO-PS:TID (ISE = 0.0270). In the bilateral scenario, ISE reduces to 0.0075 compared to 0.0872, and under contract violation to 0.00251 compared to 0.1445. Sensitivity analysis shows stable performance with ISE varying from 0.0125 to 0.0135 under ±25% parameter changes. These findings indicate that the suggested approach can significantly improve damping and minimize frequency deviation compared to the existing best controller, which makes it highly applicable to operation of a deregulated power system.