Fractional order PID control for LFC problem of a hydro-thermal power system

This paper presents a fractional order proportional integral derivative order controller, popularly known as FOPID controller for load frequency control problem of a two-area hydro-thermal power system. The objective of this study is to present a non-conventional way of robust control for the load frequency control problem. In this study, a performance index — Integral of absolute error has been used to formulate a cost function which is later minimized using differential evolution algorithm. The algorithm solves the optimization problem and determines the optimal value of parameters of FOPID controller. The FOPID controller has been tested under different operating conditions to verify its superiority over proportional integral (PI) controller. The system response obtained through simulation studies using FOPID controller has been compared with PI controller and the obtained response of system displays the effectiveness of FOPID control over PI control.