Coherency Reduction in the Epri Stability Program

The implementation of coherency-based system reduction within the EPRI stability program is described. The objective of the implementation is to reduce the effort of simulations out to tens of seconds, by accurately reducing the model size. It has been tested on 49, 443 and 1454 bus test systems. Computational savings of around 50% have been demonstrated with essentially insignificant loss of simulation accuracy.