Assessing vulnerability to cascading outages

This paper addresses the testing and implementation of a fast process for sequential contingency simulation in order to identify potential cascading modes due to thermal overloads. It also presents computation of the vulnerability index of cascading, based on the estimated likelihood and consequences of cascading outages. The approach described in this paper offers a unique capability to automatically identify initiating events that may lead to cascading outages. It predicts the development of cascading events by automatically identifying and visualizing potential cascading tiers. The proposed approach was implemented using a 50,000-bus Eastern Interconnection power system network. The results of the study indicate that initiating events and possible cascading chains may be quickly identified, ranked and visualized in on-line and offline environments. This approach may be used to improve the reliability of a transmission grid and reduce its vulnerability to cascading outages. It may be added to the existing contingency analysis tools to assess the impact of cascading events in both on-line and off-line environments.