The PJM Interconnection has proposed changes to interconnection reliability requirements for large loads, specifically, computational loads that include data centers and crypto-mining facilities, the grid operator reported on Sept. 10.
The PJM action follows a July 22 event during which nearly 4,000 MW of data center load unexpectedly disconnected from the grid in northern Virginia. As data centers disconnected from the PJM grid, they switched to run on their own backup generation facilities.
PJM and Dominion operators had to respond quickly to manage resulting imbalances between load and generation and spikes in transmission voltage and system frequency.
While the grid did not experience unresolvable reliability impacts that day, this is the third separate measurable event in the last two years, said David Souder, Executive Director – PJM System Operations.
“This type of operation is unsustainable and needs to be addressed,” Souder told the PJM Planning Committee Tuesday.
The PJM proposal, introduced at the Sept. 8 Planning Committee meeting, would establish new standards that require Large Load facilities to stay connected to the system during normally cleared transmission system disturbances, “riding through” resulting voltage and frequency excursions beyond acceptable operating limits without creating additional reliability risks for the grid.
While new proposed standards address minimum voltage and frequency ride-through requirements for existing and future Large Loads, PJM staff also intends to collaborate with existing facilities on a transition plan to adjust their existing operational parameters to comply, said Byoungkon Choi, Principal Engineer – PJM Generator Modeling & Dynamic Studies.
“PJM plans to establish these requirements as soon as possible,” Choi said.
PJM’s actions are also in response to a June 18 Federal Energy Regulatory Commission Order requiring PJM to identify gaps in processes for evaluating the reliability impacts of Large Loads.
“We are concerned that the Tariff does not specify ramp rate or ride-through requirements with which the transmission customer taking transmission service on behalf of the large load must comply,” the FERC order states.
PJM plans to file proposed solutions to FERC in November.
Next up, PJM will discuss plans in greater detail at a PC Special Session – Large Load Ride Through Education on Sept. 15.
PJM noted its proposal comes amid industrywide efforts to manage the reliability impacts of Large Load disconnections during and after normally cleared transmission system disturbances.
The PJM proposal follows standards advanced by other grid operators, including MISO and ERCOT, and PJM transmission owners, including Dominion and American Electric Power.
On a broader scale, the North American Electric Reliability Corporation (NERC) is developing Large Load reliability guidance and ride-through recommendations and standards.
NERC President and CEO Jim Robb discussed how NERC is responding to large loads in a recent episode of the Public Power Now podcast.
