Extended equal area criterion revisited

A case study is conducted on the EHV French power system in order to revisit the extended equal area criterion and test its suitability as a fast transient stability indicator. The assumptions underlying the method are reexamined, causes liable to invalidate
them are identified, and indices are devised to automatically circumvent them. The selection of candidate critical machines is also reconsidered and an augmented criterion is proposed. The various improvements are developed and tested on about 1000 stability scenarios, covering the entire 400-kV system; the severity of the scenarios, resulting from the combination of weakened both pre and post-fault configurations, subjects the method to particularly stringent conditions. The obtained results show that the devised tools contribute to significantly reinforce its robustness and reliability.