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Regulatory Updates

FERC Order No. 881-A Has Implications for NERC Compliance Programs

Dylan Achey | Jim Whitaker, PE | June 23, 2022

What is FERC and NERC Compliance?

At its May 2022 meeting, the Federal Energy Regulatory Commission (FERC) issued Order No. 881-A, to clarify a December 2021 order that represented a major change in utility operating practices and planning. In the new order, FERC denied requests for rehearing Order No. 881, and reaffirmed its Ambient Adjusted Ratings (AAR) pronouncements. These actions will have a significant impact on NERC compliance programs related to both PRC standards and facilities ratings. Utilities should review the Order’s requirements and prepare for changes needed to remain compliant.

Order 881-A Requirements

The new FERC order specifically requires:

  • Public utility transmission providers to deliver transmission service;
  • Regional transmission organizations and independent system operators (RTO/ISO) to establish and implement the systems and procedures necessary to allow transmission owners to electronically update transmission line ratings at least hourly;
  • Public utility transmission providers to use uniquely determined emergency ratings
  • Public utility transmission owners to share transmission line ratings and transmission line rating methodologies with their respective transmission provider(s) and with market monitors in RTOs/ISOs; and
  • Public utility transmission providers to maintain a database of transmission owners’ transmission line ratings and transmission line rating methodologies on the transmission provider’s Open Access Same-Time Information System (OASIS) site or other password-protected websites.

Carry Over Effects into NERC Compliance Programs

There are significant implications for NERC compliance programs, with mandatory  requirements in the areas of facilities ratings, transmission planning and power system modeling.

For example, in paragraph 26 of the Order, FERC states that:

“ [A] transmission provider establishes a higher transfer capability than the currently determined maximum facility ratings, the transmission provider must evaluate its applicable protection systems for that facility in order to comply with Reliability Standard PRC-023-4 and prevent protection settings from limiting transmission loadability. In those instances, some relay settings might require changes to maintain reliability and to accommodate the additional power transfer capability based on AARs.”

Beyond the PRC family of NERC standards, as utilities migrate toward AARs to comply with FERC’s Orders, they must review and possibly update their facilities ratings methodology documents, which are required as part of the FAC-008 compliance efforts to identify that AARs are being employed. Ratings changes through ambient weather-based adjustments may also carry over into the documentation prepared for compliance with the NERC MOD standards.

Next Steps

Utilities should carefully review the most recent FERC Order and their current facilities rating compliance process documents. Companies should be prepared to modify their facilities ratings methods and other affected NERC compliance processes program documents as necessary to maintain compliance.

With expertise in all areas of power system planning and power delivery, along with protection system engineering, TRC can provide independent technical advice and project management services to review your company’s affected compliance related documents.


Your Trusted Regulatory Advisor

TRC closely follows the national and state regulatory trends in all regions of North America. Our approach to power system engineering, planning, design,  construction and commissioning testing balances solutions that incorporate appropriate industry trends, mandatory standard requirements, regulatory guidance, compliance obligations, best practices, operational goals and budgets. With expertise in both power system planning and operations, TRC supports public utilities and private energy providers in their effort to stay ahead of the curve and to meet regulatory requirements as they evolve.

This regulatory update is provided as a service to TRC’s utility clients, helping to  keep you informed of forward-looking issues that will impact your company’s electric system reliability risks along with related topics regarding regulatory developments to help you achieve your company’s business goals.

Dylan Achey

Dylan Achey is TRC’s Manager of Generation Engineering Services. He has been leading the effort with TRC generation clients on evaluating and providing updates/information so that clients can meet applicable NERC standards. His highly technical staff perform NERC compliance standard evaluations as well as studies for both generation and transmission clients that need assistance on technical issues concerning NERC compliance. Contact Dylan at

Jim Whitaker, PE

Jim Whitaker, PE is Supervisor of Power Systems Studies at TRC. He has over 30 years of experience in Transmission and Distribution Planning, and Substation, Transmission and Distribution Engineering. His Transmission Planning projects include coordinating joint/regional 10-year transmission plans, generator interconnections, regional system assessments, as well as NERC compliance studies. His projects have included studies for both Utilities and Project Developers across the United States in the Eastern and Western Interconnection transmission systems as well as ERCOT. Prior to joining TRC, Jim worked for Xcel Energy, Peak Power Engineering, Tucson Electric Power and Virginia Power. Contact Jim at

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