Coherency Based Dynamic Equivalent Application Experience - Eastern Us Data Base

The results of calculating an equivalent for transient stability studies from a data base for the large, tightly coupled eastern US power system are presented. The method was based on generator coherency, the tendency for groups of generators to swing together. Previously developed computer programs were expanded to accommodate system sizes up to about 8,000 buses. Program input parameters controlling the calculations were varied somewhat to determine their effect. The final result was an equivalent which was significantly smaller than the original system and reasonably accurate.