October 06, 2022

The “NATF Risk Construct for Prioritizing Facility Ratings Reviews” document has been posted for industry use on the NATF public website. This document supplements the publicly posted “Key NATF Practices for Facility Ratings” document (a summary of the NATF member-confidential practices for facility ratings and how the practices address the issues and align with the controls identified by the ERO Enterprise in the November 1, 2019, ERO Facility Ratings Problem Statement) by providing a risk-based approach for prioritizing implementation of the practices, specifically baseline reviews and periodic reviews to confirm ongoing accuracy of ratings and effective operation of controls.

Given the magnitude of performing comprehensive reviews of all facilities, a Transmission Owner may want to consider a phased approach, with an emphasis on higher-risk facilities as the starting point. A good starting point is to conduct a review of a limited sample of facilities, evaluate the results, and, if necessary, expand the sample for review. This is best accomplished by initially targeting facilities with higher risk to BES reliability or higher likelihood for facility ratings error and continuing until all facilities have been reviewed.