As electricity demand continues to grow and new transmission projects face long development timelines, utilities and grid operators are looking for ways to increase the capacity of the existing transmission system. In a new report prepared for ACORE, Ambient-Adjusted Ratings and Dynamic Line Ratings, Brattle Principal T. Bruce Tsuchida compares Ambient Adjusted Ratings (AAR) with Dynamic Line Ratings (DLR) from both a regulatory and technical standpoint.

AARs, now required under FERC Order 881 as a baseline operational practice, adjust line ratings primarily for ambient temperatures and can unlock meaningful capacity relative to static or seasonal ratings, often in the range of 5% to 15%. DLR can provide larger gains – often 10% to 40% or more – because it captures wind cooling and other localized conditions. In some cases, DLR can measure conductor temperature, sag, tension, or clearance. As a result, DLR provides a more accurate line rating together with better situational awareness.

The report draws on utility case studies and industry experience, demonstrating the differences between the technologies and how DLR, when applied properly, could better reduce congestion, lower costs, and improve operational awareness by giving grid operators better visibility into system conditions.

Read the full report, available below, to learn more.

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