"Fault Cleared Properly": PJM Reviews Its Load Transfer Events

The document is a slide deck from PJM, the grid operator, titled "PJM Large Computational Load (LCL) Operational Review." Its cover reads Planning Committee, October 6, 2026.

The agenda has the deck discuss the "Operational Impetus for Large Load Ride-Through Requirements," review PJM's customer-initiated load reduction events, which it shortens to CILR, and review what FERC and NERC are doing on large loads.

Normal Cleared Faults

One slide carries the line "Large Load disconnections during and post normal cleared faults." Under it are three dates.

• "July 10, 2024, approximately 1,500 MW of load transferred to backup generation."
• "February 17, 2025, approximately 1,800 MW of load transferred to backup generation."
• "July 22, 2026, approximately 3,900 MW of load transferred to backup generation."

Below the list sits one more line: "Events raising system reliability and regulatory concerns."

Fault Cleared Properly

Each date has a slide of its own. Each of those slides carries the same short line.

"Fault cleared properly."

July 10, 2024. The slide describes "a permanent 230 kV transmission line fault due to a lightning arrestor failure." Three auto-reclosing attempts at each end of the line "resulted in six successive system faults within an 82-second period." Frequency increased to 60.047 Hz. Voltage went to 1.07 per unit, and "operators removed shunt capacitor banks to return voltages to normal operating values."

February 17, 2025. "A sustained Single Line-to-Ground (SLG) 230 kV transmission line fault." One terminal locked out immediately, and the opposite terminal completed its auto-reclosing sequence. The slide records four voltage sags across the area and a fault clearing time of "5.9 cycles (0.0983 seconds)." Frequency increased to about 60.042 Hz, and voltage to about 1.05 per unit.

July 22, 2026. "This was the largest CILR event to date," the slide says. "It was precipitated by a fault on a 230 kV transmission line following a mechanical failure." The load transferred in two stages, "with about ~2,900 MW transferring initially followed by roughly ~1,000 MW of CILR a minute later."

The next slide lists that event's "Impacts to the Grid." Reporting ACE reached +3,928 MW. Frequency in the Eastern Interconnection reached 60.092 Hz. The highest voltage recorded was about 1.138 per unit, which the slide gives as about 261.74 kV. The energy management system alarms are counted too: 655 rate of change alarms and 428 frequency alarms.

FERC & NERC Large Load Efforts

The last part of the deck is headed "NERC & FERC."

A slide on NERC's large load action plan lists white papers, one of them "Large Load Disturbance Performance (Expected December 2026)." It says "NERC issued a Level 3 Alert: Essential Actions to Industry." And under proposed reliability standards it lists "FERC Docket RD26-7-000 directing NERC to file by Dec. 31, 2026."

Two slides are headed "Draft LLWG Recommendations." The action plan slide lists a "NERC LLWG" among its items.

One recommendation asks for criteria for applicability and implementation timelines, "including consideration of both new and existing computational load sites." The next begins "Ensure existing sites are addressed," and asks that compliance be required unless technical limitations are documented. It gives its reason: "all observed Customer Initiated Load Reduction (CILR) events have involved already operational facilities and excluding them would leave the identified reliability risk unmitigated."

On voltage, the draft says to consider ERCOT's voltage ride-through requirements as the minimum baseline, while extending ride-through obligations to cover the full duration of credible disturbances.

After a fault, it gives "a default recovery level of at least 90% of pre-disturbance consumption," with modification based on system studies.

It also asks for requirements on the maximum current consumption of the computational load site during a disturbance.

The last slide before the questions is about FERC. "On June 18, 2026, FERC issued a Section 206 Show Cause Order to determine whether PJM's Tariff adequately addresses Large Loads integration." Among other things, the slide says, the order asks whether additional requirements are needed for "ride-through performance during system disturbances" and for "ramp-rate limitations and load restoration behavior."

Then one line more: "PJM plans to file revisions to address FERC's concerns (target: November 2026)."