September 19, 2008 ARC Event

Friday September 19th 2008 21:05 EST through 21:15 EST ARC Event

Midwest ISO invoked the ARC procedure due to a 500 MW Net Schedule Interchange obligation change over a 10 minute period created by schedule changes and loss of generation for 600 MW. Up to 36 percent of the available ARC operating reserves were utilized during this period to assist in correcting the imbalance. There were no ARS events initiated during the event.