Ambient Adjusted Rating Platform
for Transmission Lines

Ambient Adjusted Ratings; Optimized


SMARTLINE AAR/881’s advanced approach to ambient adjusted transmission line ratings (AAR) ensures visibility to maximum line capacity while minimizing risk.  By computing AAR ratings for each hour of the next 10 days, SMARTLINE AAR/881 provides system operators with needed short-term rating visibility, while providing further-forward looking forecasts to power marketers.

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SMARTLINE AAR/881 provides insight into ambient temperature's impact on line ratings.

Hourly AAR. Updated Hourly.

SMARTLINE AAR/881 provides transmission operators with a simple, unified solution to implement ambient adjusted line rating requirements. Implemented on any line or your entire system within days, the system provides:

  • Up to 10‐days of hourly AAR forecasts, updated hourly, based on up-to-the hour weather forecasts.
  • Line ratings based on individual line characteristics.
  • Ability to import ratings directly to your EMS.
  • A traceable, proven, rating methodology.

Consistent with the spirit of AAR, no sensors are required to be installed on any transmission line.

More Capacity, Less Risk


Traditional AAR approaches commonly treat transmission lines as the same or very similar in the way the line behaves, and in the geography in which they are located.  This increases the risk of overstating capacity from inadequate modeling, and risks understating capacity by assuming uniform behavior.

SMARTLINE AAR/881 treats each line as a unique entity, by looking at each line’s physical and geographic characteristics.

The result is an optimal picture of your transmissions system’s ambient adjusted capabilities.

Transmission lines are as different as people.

The simple addition of Lindsey TLM transmission line monitors upgrades a line from AAR to DLR.
Future Proof

Simple Path to DLR

As part of the SMARTLINE transmission line rating platform, upgrading an individual line from AAR/881 to full dynamic line rating (DLR) is as simple as installing Lindsey TLM conductor monitors on select spans. No new software or further integration is required. SMARTLINE AAR/881 provides not only a comprehensive AAR solution, but a simple path to DLR when needed; a true future-proof system for developing operational transmission line ratings.

The SMARTLINE Advantage

Proven Methodology

SMARTLINE AAR/881 ratings are developed using a comprehensive and easily documented method based on a combination of industry standards and time proven processes.

All SMARTLINE line rating systems use time-proven methods.

IEEE Standard 738 or CIGRE TB601
Regardless of whether you use the IEEE or CIGRE heat exchange formulas, SMARTLINE ensures the developed rating will not heat the conductor beyond its maximum average conductor temperature (MACT) limit.

CIGRE Technical Brochure TB299
SMARTLINE AAR/881 uses this the principles in this guide – developed by a joint IEEE and CIGRE task force – in developing ambient adjusted ratings.

SMARTLINE Methodology
Proven in use by utilities for over a decade, the SMARTLINE method includes the use of multiple, carefully selected, AAR computations over the path of the line to ensure ratings reflect the impact of temperature and solar radiation differences across the length of the line.

Utility Analysis
Any parameters used in developing a line’s rating can be modified to reflect the transmission operator’s own engineering analysis of a line.

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Contact us to set up a discussion or presentation on how SMARTLINE AAR/881 can help you get the most from your system.