A recent cyber disruption to the U.S. grid involved a “denial of service condition” at a Western utility, according to a Department of Energy official. On March 5, an unidentified power company fell victim to a “cyber event” that interfered with operations but stopped short of causing blackouts, according to a DOE filing this week. A DOE official confirmed yesterday that the event “did not impact generation, the reliability of the grid or cause any customer outages.”