POSTED BY: USGRIDSEC 2019-01-12
The Midcontinent Independent System Operator (MISO) sent a real time notification on Friday, January 11th of an observed large frequency swings that was picked up on measurement devices across the United States Eastern Interconnection. The divergent frequency observations began of 4:45 am eastern and continued to approximately 5:00 am.
In a related posting from the PowerIT Lab at University of Tennessee, Knoxville/Oak Ridge National Lab, the frequency swings can be observed from data collection through Phasor Measurement Units that are deployed across the nation. The cause of the Frequency swings has not yet been determined.