Major Blackouts of the Decade: Underlying Causes, Recommendations and Arising Challenges

Large disturbances in electric grids lead to severe load-generation imbalances, thus resulting in power outages or blackouts. Blackout is a phenomenon that occurs not because of a single cause, but due to multiple cascading disturbances. A critical review of such events can help in drawing preventive strategies and ensures readiness to mitigate the risk of blackouts. In this context, the work reviews the causes and severity of blackouts of various geographical locations in the past decade. An attempt has been made to summarize major blackouts and their effects. Some recommendations are also presented to provide strategies for grid protection and to mitigate the severity of blackouts. Further, an index to identify potential category of events that may cause a blackout in a geographical location is formulated. Finally, the work highlights few challenges arising due to transition in power systems. This work helps system operators and planners to develop grid technologies, electricity market models, and grid codes for improving system resilience.