Groups Urge FERC To Hold Off On Dynamic Line Ratings Requirement Consideration

by Paul Ciampoli
APPA News Director
May 2, 2022

The Federal Energy Regulatory Commission (FERC) should hold off on considering a requirement to utilize dynamic line ratings (DLRs) while the power industry implements a closely related ambient adjusted line ratings requirement, the American Public Power Association (APPA) and the Large Public Power Council (LPPC) recently said in joint comments filed at FERC.

The April 25 comments were submitted in response to a notice of inquiry (NOI) issued by FERC earlier this year (Docket No. AD22-5).

The NOI sought comment on whether DLR is needed to ensure just and reasonable wholesale rates.  The Commission also sought comments on (1) whether the lack of DLR requirements renders current wholesale rates unjust and unreasonable; (2) potential criteria for DLR requirements; (3) the benefits, costs, and challenges of implementing DLRs; (4) the nature of potential DLR requirements; and (5) potential time frames for implementing DLR requirements.

APPA and LPPC said that they agree that cost-effective deployment of DLR technology has the potential to improve the economic efficiency and reliability of the grid.

But they strongly recommended that the Commission hold off on considering a requirement to utilize DLRs while the industry implements the ambient adjusted line ratings requirement that was just mandated in FERC Order No. 881.

Issued in late 2021, the final rule reforms both the pro forma Open Access Transmission Tariff and the Commission’s regulations to improve the accuracy and transparency of transmission line ratings, which represent the maximum transfer capability of each transmission line. 

The trade groups said that ambient adjusted line ratings are an element of a DLR system that will test grid operations in similar if less complex ways and promises to capture a significant portion of the benefits offered by substantially more involved and costly DLR systems.   

APPA and LPPC said that the experience their members have had with DLR systems suggests that implementation will be complicated and costly, while incremental benefits vis-à-vis ambient adjusted line ratings are not fully understood.  

“Implementation will involve a complex set of sensors, monitoring systems, communications links and analytics engines, in addition to personnel expert in the administration of these systems. Further, the automation of these systems and the necessary communications links offer new vectors for cybersecurity attacks,” the groups said.

They said that if FERC should decide to proceed with deployment of DLRs, it would be wise to limit the implementation of DLR to congested transmission facilities, with a focus on lines of 100 kV or higher, where consequential benefits are likeliest to materialize.