Design of a Linear Optimal Quadratic Regulator for Frequency Control in a Two-Area Deregulated Power Market

Meeting the load demand on an electric power system, safety and reliability have been of the utmost importance for transmission system operators worldwide. Even with the deregulation of the electricity market, this priority is still in place. The Transmission System Operator (TSO) needs to keep the frequency in the permissible interval to avoid load shedding. Since loads in a power system is a random variable, a power system is never in steady-state condition. Its frequency is fluctuating constantly. At each instance, the load balance equation should be met to keep the frequency in safe ranges. On each generator is installed an Automatic Generation Control (AGC) control system to regulate the frequency. The control of the AGC is tuned to follow the change in load demand to keep the frequency in the prescribed ranges. The design of the controller is crucial to meet these requirements. In this paper, the popular design method called Linear Quadratic Regulator (LQR) will be implemented to regulate the frequency of a two-area electricity market when the load is fluctuating in one of the areas. The results will be compared with the case when the LQR is not used to portray its role in the frequency regulation of the power system.