Massive power disconnect roiled largest US electric grid

A significant power disconnection occurred on the largest U.S. electric grid on Wednesday, causing a voltage disturbance that was felt across multiple states, according to experts and data from grid operator PJM Interconnection.

The event, which happened around 7:55 a.m. ET in northern Virginia, a major hub for data centers, lasted about 10 minutes before the grid was fully stabilized. Bob Marshall, CEO of Ting Labs, described it as a "massive event" and noted that his company's network of 1.4 million sensors recorded voltage disturbances extending from Washington, D.C., to Chicago.

PJM Interconnection reported that more than 3 gigawatts of power demand went offline, approximately 3% of the grid's total demand at the time. While PJM registered the sudden drop in demand and a change in grid frequency, it stated there were no impacts to its reliability. Customers in northern Virginia reported flickering lights and noises from appliances, indicating a significant hit to power quality.