This paper addresses a robust control method to decentralized PI-based load-frequency control (LFC) synthesis in a multi-area power system. The LFC problem is reduced to a static output feedback H∞ control problem and then it is solved using a developed iterative linear matrix inequalities (ILMI) 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. The obtained controllers are compared with full dynamic H∞ controllers. The results show the proposed controllers guarantee the robust performance for a wide range of operating conditions as well as full-dynamic H∞ controllers.
