AUTOMATIC GENERATION CONTROL USING A FRACTIONAL ORDER CASCADE CONTROLLER

Abstract

The frequency stability of power systems depends on the active power balance between the generation and demand. The varying nature of the demand upsets this balance which consequently results in the deviation of the frequency of the system from its nominal value. In order to stabilize the frequency, the generation is continuously adjusted with the help of a controller to match the load at all times. This control process is called automatic generation control. This study proposes a new structure of fractional order cascade controller, namely fractional order proportional integral – fractional order tilt integral derivative (FOPI-FOTID) controller for automatic generation control (AGC) of a four-area deregulated power system. The parameters of the controller were optimized using the Grasshopper Optimization Algorithm (GOA). The superiority of the proposed controller was evaluated by comparing its performance against a non-cascade FOTID controller and a cascade tilt integral – tilt integral derivative (TI-TID) controller, under a step load perturbation in the power system. The recorded improvements over the cascade TI-TID controller are; 47%, 18.7%, 30.7% and 23.04% for the settling time, and 56.9%, 70.9%, 62.6% and 56.86% for the undershoot of the frequency deviations of area-1, area-2, area-3 and area-4 respectively; 32.86%, 3.13% and 23.0% for the overshoot of the frequency deviations of area-2, area-3 and area-4 respectively.