Prevention of cascading outages in Con Edison's network

This paper describes the framework for prevention of cascading outages caused by thermal overloads. The approach presented in this paper is a fast, flexible and automated process for assessment of cascading outages and their prevention. It helps to prevent the cascading outages by optimizing the existing available controls in the transmission network. Optimal remedial actions are applied first after the occurrence of an initiating event, and then at each cascading Tier, until the cascading event is mitigated. The paper also presents the ranking of cascading outages that is based on a minimum amount of load curtailment which is needed to alleviate the steady-state stability violations caused by cascading events. The approach was implemented using the Con Edison's 50,000-bus planning case. The study results show that this approach is very effective in improving the reliability of Con Edison's network and preventing major blackouts, caused by the cascading outages. The analysis may also be included as part of NERC-compliance studies. Con Edison is planning to extend the assessment of cascading outages by incorporating transient stability analysis.