April 18, 2008 ARC Event

April 18, 2008 ARC Event

Friday April 18, 2008 from 05:00 EST through 05:10 EST the Midwest ISO invoked the ARC procedure due to ~1,000 MW of generation forced off line from an earthquake. Up to 15 percent of the available ARC operating reserves were utilized during this period to correct the imbalance. There were no ARS events during the ARC procedure.