Influence of amortisseurs on stabiliser design requirements for damping local oscillations of a generator

This paper introduces a new small perturbation model for the well known "generator/infinite bus" system, that includes explicit representation of amortisseur windings. The major points of difference between this model and the conventional Heffron-Phillips small perturbation model are discussed by a comparison of synchronising and damping torque coefficients obtained from them. The design and tuning requirements of a conventional generator power system stabiliser (PSS), principally intended to damp out local oscillations, are reconsidered to accommodate amortisseur effects as reflected in the new generator model. It is shown that the PSS transfer function may now assume a different generic form, as well as a different set of compensatory time constants.