Evaluation of a quasi-optimal state feedback excitation strategy for power system stability

A method is presented for finding time-optimal (or suboptimal) excitation control for power system stability. The control is found directly as a function of the states of the system, which can be measured. A closed-loop control is found for the linearized system first, then the method is extended to the nonlinear model. The results obtained for the single-machine infinite bus problem are compared with those obtained by a steepest descent method. For small disturbances where linearity holds, the closed-loop scheme gives optimal solutions, while, for large disturbances, it yields a sub-optimal solution.