PJM Interconnection, the operator of the U.S. Eastern power grid, said on Tuesday it is considering strengthening grid connection reliability requirements for "computational loads" such as data centers and cryptocurrency mines. The move stems from an event on July 22 in which about 3,800 megawatts of data center load in Northern Virginia was disconnected, the largest such event in PJM's history.

PJM stated in a statement that the event was triggered by a fault on a 230-kilovolt line in Dominion Energy's territory, leading to a severe imbalance between generation and load, accompanied by significant fluctuations in voltage and frequency. The event occurred in two waves, with PJM's total load dropping from 99,984 megawatts to 96,205 megawatts, a decrease of about 3.8%.

PJM said it restored the Balancing Authority Area Control Error Limit within 9 minutes, while the North American Electric Reliability Corporation (NERC) standard is 30 minutes. Additionally, PJM dispatched reactive power resources to reduce system voltage.

PJM noted that Northern Virginia, where Dominion Energy is located, is home to the world's largest data center cluster, and two similar events occurred in 2025 and 2024, each causing a sudden shift of about 1,500 megawatts of load.

The issue was discussed at PJM's Operating Committee meeting on August 6. PJM staff said data centers may be overly sensitive to grid conditions. Emanuel Bernabeu, chairman of the Operating Committee, said at the meeting: "This was a normal-cleared fault. They should not have disconnected. These data centers are overly sensitive to the voltage they prefer, and we believe they disconnected too early."

As a result, PJM is evaluating potentially expanding its reliability requirements, "considering existing and future industry ride-through standards and practices," said Matthew Wharton, PJM's manager of reliability engineering.

PJM's move comes as NERC is beginning to develop reliability requirements for computational loads. Under a directive from the Federal Energy Regulatory Commission (FERC), NERC must complete registration criteria and preliminary reliability standards for incorporating computational loads into the bulk power system by December 31. NERC will also develop a plan for additional reliability standards for computational loads by March.

However, PJM noted that NERC will not address minimum voltage or frequency ride-through requirements until sometime next year. David Souder, PJM's executive director of system operations, said at the meeting: "These requirements really need to be in place before loads connect to the system."