Robust Fractional Order Proportional, Integral and Derivative Stabilizer for Power Systems

Abstract

This paper focuses on the application of a robust Fractional Order PID (FOPID) stabilizer tuned by Genetic Algorithm (GA). The system’s robustness is assured through the application of Kharitonov’s theorem to overcome the effect of system parameter’s changes within upper and lower limits. The FOPID stabilizer has been approximated during the optimization using the Oustaloup’s approximation for fractional calculus and using the “nipid” toolbox of Matlab during simulation. The objective is to keep robust stabilization with maximum achievable degree of stability against system's uncertainty. This optimization will be achieved with the proper choice of the FOPID stabilizer’s parameters (kp, ki, kd, l, and d) as discussed later in this article. The optimization has been done using the GA which limits the boundaries of the tuned parameters within the permissible region. The calculations have been applied to a single machine infinite bus (SMIB)power system using Matlab and Simulink. The results show superior behavior of the proposed stabilizer over the traditional PID.