PROJECT TITLE :

A Two-Level Probabilistic Risk Assessment of Cascading Outages

ABSTRACT:

Cascading outages in power systems can cause major power disruptions and blackouts and involve a giant range of different mechanisms. The typical development of a cascading outage can be split in 2 phases with completely different dominant cascading mechanisms. As an influence system is usually operated in security, an initiating contingency cannot entail a fast collapse of the grid. But, it can trigger a thermal transient, increasing considerably the probability of extra contingencies, during a “slow cascade.” The loss of extra parts can then trigger an electrical instability. This is the origin of the following “quick cascade,” where a fast succession of events will lead to a major power disruption. Several models of probabilistic simulations exist, however they have an inclination to focus either on the slow cascade or on the quick cascade, in keeping with mechanisms thought-about, and infrequently on both. We tend to propose during this paper a decomposition of the analysis in 2 levels, ready to mix probabilistic simulations for the slow and therefore the quick cascades. These two levels correspond to those two typical phases of a cascading outage. Models are developed for every of those phases. A simplification of the general methodology is applied to two test systems to illustrate the concept.