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Ambient-Adjusted Ratings

A transmission facility rating.

Definition by MISO

Source: 1 (p10)

A transmission facility rating that: (1) applies to a time period of not greater than one hour; (2) reflects an up-to-date forecast of ambient air temperature across the time period to which the rating applies; (3) reflects the absence of solar heating during nighttime periods where the local sunrise/sunset times used to determine daytime and nighttime periods are updated at least monthly, if not more frequently; and (4) is calculated at least each hour, if not more frequently.

Last modified: 2025-11-02

Related: dynamic-line-ratings

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  1. MISO (2023). FERC Order 881 Update. https://cdn.misoenergy.org/20230822%20RSC%20Item%2005%20FERC%20Order%20881%20Update%20(RSC%202018%2054A)%20(RSC%202021%2054B)629904.pdf ↩