A new method of fast assessment of transient stability margins

In this paper, novel and efficient stopping criteria for post-fault trajectory simulation are proposed for expediting the speed of transient stability assessment. Based on the criteria, an improved hybrid algorithm is developed to determine a stability margin for fast derivation of the transient stability limit. The algorithm combines the merits of fast speed of the potential energy boundary surface method and reliability of the time domain simulation method. Extensive tests are performed on several systems including the 10-generator New England test system, the 17-generator Iowa reduced system and the IEEE 50-generator test system. The result demonstrates that the proposed criteria are reliable, and that the algorithm is a potential tool for on-line calculation of transient stability limit and critical clearing time