A qualitative approach to the transient stability analysis [of power systems]

With the growing stress on today's power systems, there is a urgent need for implementing online dynamic security assessment (DSA). Among the functions of DSA, the most time-consuming function is the dynamic contingency analysis. In this paper, it has been assumed that during this analysis, one is not interested in obtaining trajectories with a very high accuracy but is primarily interested in a qualitative answer to the question: is the power system stable or not? Subsequently, only unstable or marginally stable cases have to be considered for more detailed analyses and preventive control. This idea is applied to parallel-in-time algorithms for transient stability analysis in order to stop the simulation as soon as the stability is detected by the condition of potential energy boundary surface (PEBS) crossing. The effectiveness of the approach has been validated on the New England test system and a realistic-sized network with 662 buses. An implementation on the nCUBE multiprocessor of a particular parallel-in-time algorithm allows the speed up derived from the proposed approach to be assessed.