Facility Ratings Best Practices and Workbook Management

Accurate Facility Ratings are a risk element in the 2025 Compliance Monitoring and Enforcement Program (CMEP) Implementation Plan (IP) because they are crucial for ensuring the reliability of the Bulk Electric System (BES). It is imperative that Transmission Owners (TOs) and Generator Owners (GOs) maintain Facility Ratings that are based on accurate equipment inventories that yield adequate transmission planning and modeling results.

Prioritizing Consistency

Entities should ensure that their Facility Ratings workbook is consistent with the Facility Ratings Methodology (FRM). Ensuring the Facility Ratings workbook data is accurate and consistent will help confirm implementation of the methodology as it relates to the calculations and assumptions used. Consider implementing consistency checks as part of internal controls to ensure:

• Equipment manufacturer specifications, such as nameplate data, are consistent with the Facility Rating documentation/workbook.
• One-line and elevation diagrams match the Facility Rating documentation/workbook.
• Facility Rating documentation/workbook information matches what is provided to the Electric Reliability Council of Texas (ERCOT) for accurate modeling purposes.

Periodic Reviews

Entities should have internal controls to prompt a review of Facility Ratings with an emphasis on risk management.​ These reviews may take place during (but are not limited to) planned or unplanned maintenance work involving changes. Walk-down activities to assess the existing Facility Ratings are accurate should also be considered as part of periodic reviews and the periodicity of the walk-downs should be determined by a Facility’s age. Peer-review of these activities will further enhance this process.

Change Management

Below are some questions posed to entities that may be helpful regarding their change management processes:

• Does the entity have a change management process? ​Is the change management process addressed in the Facility Ratings Methodology?​
• When equipment is replaced, how does the entity ensure that the Facility Ratings remain accurate?​
• Does the entity have internal controls designed to prompt a review of Facility Ratings?​ Who is responsible for this review?

Incorporating internal controls in the entity’s change management process will ensure that field equipment inventories match the Facility Ratings workbook and documentation.​ Additionally, documenting roles and responsibilities will help ensure these processes flow smoothly and without interruption.

Workbook Best Practices

CMEP personnel encounter many types of Facility Rating documentation and workbooks. Some best practices for organizing Facility Rating data include:

• Acknowledge and identify the most limiting element (MLE) for each Facility​.
• When documenting Facility Ratings, include a column where supporting documents can be listed​. Doing so will allow entity personnel to easily access and confirm that its Facility Ratings are correct.
• Include all relevant equipment (BES and non-BES​) and consider adding a column labeling BES and non-BES equipment for clarity.

Including the complete scope of equipment helps ensure that all equipment Ratings are considered when identifying the MLE. Refer to the Standard language and make use of the Bulk Electric System Definition Reference Document as needed.

Record Management Best Practices

Entities should consider establishing revision tables in order to capture, review, and update details. Include relevant information such as dates, personnel name and title, and brief comments or descriptions of the changes made.

Accurate Facility Ratings are essential to the reliability of the BES. Entities can help ensure correct Facility Ratings are documented and maintained by implementing internal controls for change management, periodic reviews, and referencing of supporting documentation.