Pole-placement designs of power system stabilizers

Four pole-placement techniques for the design of power system stabilizers are examined, with emphasis on their frequency-response characteristics. A link between the modal frequency-response method and the closed-loop system electromechanical modes is established. It is shown that to provide the same amount of damping enhancement, the controllers should have similar gains and phases at the model frequency, provided that a resonance condition is avoided. The effect of low and high-frequency response of the controllers on both interarea mode damping and potentials of torsional interactions is examined. A simple procedure is presented to obtain controllers exhibiting desirable frequency-response characteristics that are suitable for multiple operating conditions