The North American Electric Reliability Corp.’s independent Board of Trustees approved an important standard addressing a key recommendation from the U.S. – Canada Joint Task Force on the Aug. 14, 2003 blackout last week. Developed through a two-year, ANSI-accredited process, the standard, PRC-023-1 "Transmission Relay Loadability" is now mandatory in New Brunswick and Ontario and will move to the Federal Energy Regulatory Commission for approval in the United States.

NERC standards are designed to ensure the reliability of the bulk power system in North America by preventing system disturbances and enabling the rapid containment of these incidents when they do occur. The PRC-023-1 standard specifies technical requirements for setting protective relays – equipment designed to automatically protect transmission lines from damage during extreme system conditions – so that operators are better able to manage disturbances.

“Relay loadability has been a contributing factor in major system disturbances since 1965, and was a major contributor to the severity of the 2003 blackout,” commented Bob Cummings, NERC’s director of event analysis and information exchange. “Following the 2003 event, the industry completed a detailed review of protection system loadability to ensure relays will not prematurely operate during extreme conditions, thereby allowing operators enough time to make system adjustments. This standard makes the improvements made at that time both permanent and enforceable."

“The approval of this standard represents a major milestone in ensuring system reliability as we continue to follow through on the recommendations issued by the U.S. – Canada Joint Task Force,” said Rick Sergel, NERC president and CEO. “We look now to federal authorities to quickly pass this critical standard.”