Ambient Adjusted Rating Platform
for Transmission Lines

Simplify Compliance to FERC Order 881


Building on 10‐years experience in providing transmission line rating systems, SMARTLINE AAR/881 adds Ambient Adjusted Rating (AAR) capability to the SMARTLINE platform. This sensor free system supports all the requirements for AAR as set forth in FERC Orders 881 and 881‐A, “Managing Transmission Line Ratings”, while providing fully operation transmission capacity forecasts.

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

A Complete FERC Order 881 Solution

SMARTLINE AAR/881 provides transmission operators with a simple, unified solution to implement the ambient adjusted line rating requirements as set forth in FERC Order 881.

Implemented on any line or lines within days, the system provides:

  • The required 10‐days of hourly AAR ratings with the required duration and frequency of updates.
  • The use of all required environmental parameters.
  • The ability to provide ratings directly to system operators as well as RTOs/ISOs.
  • A traceable, proven, rating methodology.

The SMARTLINE AAR/881 system develops ambient adjusted ratings for any line.  Consistent with the spirit of AAR, no sensors are required to be installed on any transmission line.


Time Proven Methodology

FERC Order 881 requires line ratings be “computed in accordance with a written transmission line rating methodology.”


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

Elements Required by Order 881
As required AAR/881 uses continuously updated ambient and forecast ambient temperatures and distinguishes between daytime and nighttime hours.

IEEE Standard 738
The standard heat exchange formulas identified in IEEE Standard 738 are used to ensure 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 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.


A Complete FERC Order 881 Solution

SMARTLINE AAR/881 is a comprehensive, highly secure, cloud-based system that is easy to integrate into utility applications, while providing useful graphical tools for engineering analysis.

Cyber Secure
Two-factor authentication, regular penetration testing and more ensures a highly secure operating environment.

Application Programming Interface Included
SMARTLINE AAR/881 includes an easy to use API to allow for quick integration in EMS and other utility applications.

Weather Data
Use SMARTLINE’s or your own preferred weather feeds with AAR/881. All line rating weather data is also made available through the API.



Simple Upgrade to Dynamic Line Rating

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.

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Contact us to set up a discussion or presentation on how SMARTLINE AAR/881 can help you meet the requirements of FERC Order 881.