Robust control design of power system stabilizers using multivariable frequency domain techniques

H_∞ and structured singular value optimization techniques are used to design robust power system stabilizers (PSSs) for a single-machine and a two-machine system with varying operating conditions. Realistic uncertainty models to represent the possible operating conditions as perturbations from a nominal condition are developed. System experience is used to select weighting functions to provide adequate damping and shape the controller frequency response. Computer simulations show that the PSS designed by using the proposed technique provides improved damping compared with a conventional PSS. Although the design is successful, the design process could benefit from the development of more systematic techniques for the selection of weights to shape controller frequency response, to affect closed-loop damping, and to eliminate controller right-half-plane zeros