Design of Fractional Order PID Controller for Load Frequency Control in Perturbed Two Area Interconnected System

The vital concern of the load frequency control in an interconnected system is to minimize the frequency and tie-line scheduled power variations. A robust controller is required to overcome these concerns in a power system. This paper presents an interval fractional-order proportional integral derivative controller design technique for load frequency control in power system. The controller has been designed for frequency control of two area interconnected system using stability boundary locus method. The controller design involves perturbation in the system parameters (+/- 50%) using the Kharitonov theorem rather than using fixed values. The analysis of the designed controller has been performed by changing system parameters such as governor constant, turbine time constant and step load perturbation (magnitude and location). Further, the performance of the controller has also been monitored under the effect of non-linearities (GRC and GDB). Simulation results illustrate that proposed controller gives better results than the conventional methods.