*** BULLETIN ***
At about 12:30 p.m. (eastern) a major disturbance on the transmission system in the Pepco area caused several power plants and transmission lines to shut down. As a result, some retail customers lost electric service. Local utilities will have details on those outages. At the transmission level, the outages of customers equaled between 200 and 500 megawatts of power. The problems seem to be limited to the D.C.-Maryland area.
PJM and local utilities are restoring power supplies and electric service. The transmission grid is stable. The cause of the disturbance is under investigation.
Three generating units shut down, totaling about 2,000 MW.
No other information has been confirmed at the grid level.