Comparison of DE optimized PID controllers for AGC of interconnected power system

Abstract

The Differential Evolution (DE) algorithm has been employed for tuning the parameters of the PID controllers existing into the load frequency control (LFC) system of standard interconnected thermal power system by considering the minimization of three objective functions based on the ITAE, damping ratio of dominant eigen values and settling times of frequency and tie line power deviations. The disturbance of 0.1 p.u. step load change is considered in to the area-1 at time t=0 second by keeping no change in area-2 and the system performance has been evaluated in terms of damping ratio, ITAE value, the dynamic responses and time domain specifications. The system performance with PID controllers tuned using DE, are also compared with the performance of the same system optimized by the different techniques in literature such as: BFOA tuned PI controllers, GA tuned PI controllers and DE tuned PI controllers. In the present work, the results show that the better dynamic responses have been obtained by the proposed DE tuned PID controllers with less settling times, smaller overshoots, good damping behavior for the oscillations and less ITAE value as compared to some other techniques mentioned above.