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Regulatory Updates

FERC Issues Notice of Inquiry Regarding Dynamic Line Ratings

Jim Whitaker, PE | April 25, 2022

On February 17, 2022, the Federal Energy Regulatory Commission (FERC) issued a Notice of Inquiry (NOI) to explore the issues that could result by shifting from the seasonally-fixed facilities ratings currently used in utility operations to the more complex implementation of Dynamic Line Ratings (DLR).

FERC defines DRL as a transmission line rating that: “(1) applies to a time period of not greater than one hour; and (2) reflects up-to-date forecasts of inputs such as (but not limited to) ambient air temperature, wind, solar heating intensity, transmission line tension, or transmission line sag.”

The order requests comment on whether and how the required use of DLR is needed to ensure just and reasonable whole sale electric rates. There are significant technical challenges involved in implementing DLR in the planning and operation of utility systems. Utilities are encouraged to consider how they would implement a DLR based system.

About the NOI

FERC’s NOI seeks comment on whether the current lack of DLR requirements renders wholesale rates unjust and unreasonable; potential criteria for implementing DLR requirements; the benefits, costs, and challenges of implementing DLR; the nature of potential DLR requirements; and potential timeframes for implementing DLR requirements.

The NOI builds upon FERC Order No. 881 issued on December 16, 2021 where FERC found that the use of only seasonal static temperature assumptions in developing transmission line ratings would result in ratings that do not accurately represent the transfer capability of the transmission system. In its previous order, FERC mandated that all utilities implement ambient adjusted ratings.

Next Steps

Utilities should carefully review the FERC Notice of Inquiry and seek advice on how to implement a dynamic line rating program that minimizes both operating reliability risk and compliance risk. Companies should be prepared to modify their NERC compliance programs as necessary to address the potential introduction of DLR in their businesses.

With expertise in all areas of power system planning and power delivery, protection system engineering, TRC can provide independent project management services to review your company’s facilities ratings  program.


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.

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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