This paper presents the design of an intelligent fuzzy
gain scheduled proportional-integral (FGSPI) controller as the
supplementary controller for load frequency control (LFC) of
two-area interconnected power system with reheat type thermal
unit of equal capacity in each area. The dynamic response has
been studied for 1% step load perturbation in area-1. The
proposed FGSPI controller is compared against conventional
proportional-integral (PI) controller and state feedback linear
quadratic regulator (LQR) controller using settling times,
overshoots and undershoots of the tie-line power and frequency
deviations as performance indices. Comparative analysis
indicates that the proposed intelligent controller gives better
performance than conventional controllers.