Effective damping for SSR analysis of parallel turbine-generators

Damping is a dominant parameter in studies to determine SSR (subsynchronous resonance) problem severity and countermeasure requirements. To reach valid conclusions for multiunit plants, it is essential that the net effective damping of unequally loaded units be known. For the Palo Verde Nuclear Generating Station, extensive testing and analysis have been performed to verify and develop an accurate means of determining the effective damping of unequally loaded units in parallel. This has led to a unique and simple algorithm for calculating the effective damping which correlates well with two other analytic techniques. The features of this algorithm are discussed, and correlation results are presented