A FO-PID controlled Automatic Generation Control of multi area power systems tuned by Harmony Search

Background: Power system stability demands minimum variation in frequency, so that load generation balance is maintained throughout the operation period. An Automatic Generation Control (AGC) monitors the frequency and varies the generation to maintain the balance. A system with multiple energy sources and use of a fractional controller for efficient control of stability is presented in the paper. At the outset a 2-area thermal system with governor dead hand, generation rate constraint and boiler dynamics have been applied. Methods: A variation of load is deliberated for the study of the considered system with Harmony Search (HS) algorithm, applied for providing optimization of controller parameters. Integral Square Time Square Error (ISTSE) is chosen as objective function for handling the process of tuning controller parameters. A study of similar system with various lately available techniques such as TLBO, hFA-PS and BFOA applied to PID, IDD and PIDD being compared to HS tuned fractional controller is presented under step and dynamic load change. The effort extended to a single area system with reheat thermal plant, hydel plant and a unit of wind plant is tested with the fractional controller scheme. Results: The simulation results provide a clear idea of the superiority of the combination of HS algorithm and FO-PID controller, under dynamically changing load. The variation of load is taken from 15 to 5% of the connected load. Conclusion: Finally, system robustness is shown by modifying essential factors by +/- 30%.