PJM Facilitating Dynamic Line Rating Implementation


PJM and its stakeholders are working to finalize the systems and procedures necessary to permit the acceptance of dynamic line rating systems as directed by the Federal Energy Regulatory Commission.

Through a series of special sessions of its Operating Committee dedicated to dynamic line ratings, or DLRs, changes to operation systems and procedures are being discussed to allow for regularly updated inputs of transmission line rating data from transmission owners’ DLR devices.  PJM held the first special session with stakeholders on Feb. 25.

FERC Focus on Transmission Efficiency

On Dec. 16, FERC issued Order 881, which added new definitions and requirements around ambient-adjusted ratings, including the allowance for “at least hourly” updates. The order also directed PJM to facilitate operational implementation of DLR systems to better reflect actual transfer capability.

“Transmission line rating practices in RTOs/ISOs that do not permit the acceptance of DLRs from transmission owners that use DLRs are contributing to unjust and unreasonable wholesale rates by acting as a barrier to accurate transmission line ratings,” FERC Order 881 stated. “We require RTOs/ISOs to establish and maintain the systems and procedures necessary to permit the acceptance of DLRs from transmission owners that use them.”

PJM has proposed an accelerated stakeholder process to accomplish the initial DLR work early in 2022 within the scope of the Operating Committee. This will allow a PJM TO with a production DLR deployment in June.

PJM DLR Experience

Dynamic line rating technology is not entirely new to PJM.

From 2016 to 2018, for example, PJM and AEP partnered on a pilot project to study DLR implementation on two transmission lines.

In the winter of 2020, PJM and PPL worked on a DLR program for its transmission lines. Data from that project suggested that DLR sensors could reduce realized congestion, eliminating the need for a market efficiency project to rebuild or construct a new transmission line.

FERC Order 881 arrived as PPL was actively engaged in implementing DLR for two of its PJM transmission lines to be used within PJM production operations and market systems that leverage facility ratings. As these are going to be utilized in day-ahead and real-time systems, from a PJM perspective, it is the first production deployment of such technology.

Exploring Benefits and Challenges of DLR Systemwide

In keeping with FERC orders, PJM and stakeholders will also discuss how introduction of regularly updated DLR data may contribute to optimization of PJM reliability.

Additional discussion within the stakeholder process is expected to include the treatment of new transmission line capacity data in PJM markets. DLR data may also affect ratings used in PJM transmission planning market efficiency analysis.  As directed by a recent FERC notice of inquiry on Feb. 17, PJM expects to respond with comments on whether and how required use of DLRs may be necessary to ensure just and reasonable rates within the comment period that ends April 25, 2022.