Automatic Generation Control : A Decentralized Robust Approach 275 2 . AUTOMATIC GENERATION CONTROL

Automatic Generation Control (AGC) problem has been one of the major subjects in electric power system design/operation and is becoming much more significant today in accordance with increasing size, changing structure and complexity of interconnected power systems. In practice, AGC systems use simple proportional-integral (PI) controllers. However, since the PI controller parameters are usually tuned based on classical or trial-and-error approaches, they are incapable of obtaining good dynamical performance for a wide range of operating conditions and various load changes scenarios in a multi-area power system. In this paper, in order to design a robust PI controller for the AGC in a multi-area power system, first the problem is formulated as an static output feedback control problem, and then it is solved using a developed iterative linear matrix inequalities algorithm to get an optimal performance index. A three control area power system example with a wide range of load changes is given to illustrate the proposed approach and the results are compared with dynamic output feedback control design. ∞ H