Power systems are in transition from large, vertically integrated utilities providing power at regulated rates to restructured systems with competitive companies selling unbundled power at lower rates. In new environment, a power system includes separate generation, transmission and distribution companies with an open access policy. The classical control methodologies do not satisfy new objectives and novel control strategies are needed to maintain system reliability and meet new demands. This paper presents a reduced-order robust load-frequency controller for a restructured power system using singular values theorem. The singular values of the system observability matrix of the high order µ-controller are analyzed, and a method is used to achieve a low order load-frequency controller without degradation of the closed loop system performance. The proposed technique is tested on a power system using computer simulation.
