Performance analysis of WOA optimised PID controllers for LFC of interconnected thermal power systems

Abstract

Nature inspired whale optimisation algorithm (WOA) has been implemented for load frequency control (LFC) of two-area interconnected non-reheat thermal power systems in order to maintain the system frequency at a prescheduled value in the presence of disturbances. Two similar PID controllers have been used in each area and control optimisation problem for proper tuning of controllers' parameters is defined by considering the integral of time multiplied absolute error (ITAE) as an objective function. The superiority of WOA optimised PID controllers has been established by comparing the results with other existing approaches such as; BFOA/PI, DE/PI, NSGA-II/PI, GSA/PI and GWO/PI for the same system in the presence of load changes of different magnitude and location. For performance analysis, the percentage reduction in ITAE, settling times of frequency & tie line power deviations and minimum damping ratio (MDR), etc. have also been calculated. The simulation results show that the WOA/PID approach gives far better results in terms of system dynamic responses, ITAE, MDR, settling times and overshoots of Δf1, Δf2 and ΔPTie for the same system under study when compared with some existing approaches.