Partial pole placement of H_∞ based PSS design using numerator-denominator perturbation representation

A new H_∞ PSS design method which uses the numerator-denominator perturbation representation and includes the partial pole placement technique and a new weighting function selection method is proposed. This overcomes certain conventional H_∞ PSS design algorithm limitations. A sixth-order machine model is used to increase the accuracy of selected weighting functions. A robust PSS has been successfully designed for single and two-machine systems by treating the highly nonlinear characteristic of the power system as model 'uncertainty'. The design is verified to have better performance for a wide range of system operating conditions when compared with the conventional PSS designs.