Reactive Resources Impact Generator Facility Ratings

Reactive Resources Impact Generator Facility Ratings

Through audits, webinars, workshops and a variety of communications, NERC and the Regional Entities have made it clear to the industry that Facility Ratings and FAC-008 compliance are important to BES Grid Reliability. Registered Entities have instituted better controls, such as improved Change Management, third-party Mock Audits, multiple levels of reviews, and Facility walkdowns to better ensure Facility Ratings are accurate. In theory, rating your generation Facility seems pretty straightforward. Include every electrical component from the generator to the point of interconnection in the ratings documentation and analysis. However, not every Facility is the same, or quite that simple.

In recent conversations with PCS, an auditor from a Regional Entity spoke of a compliance gap that their auditors are seeing more frequently, in particular in the Facility Ratings for renewable generation Facilities. Because of their grid location and the need for Voltage Support capabilities, many renewable generation resources are required to install additional reactive resources, such as capacitor banks or DVAR banks, as a part of the Generation Interconnection Agreement. Compliance audits are finding that the reactive resources may not be included in the Facility Ratings on a consistent basis.

The total MVA output capabilities of a generation Facility must be considered in the Facility Ratings. This includes the generator output and the potential output of any reactive resources that are a part of the generation Facility. Even if control systems limit the total MVA output of the generation Facility, any reactive resources in the Facility must be a part of the Ratings Methodology and documentation.

PCS takes steps to assure that our client’s applicable reactive resources are appropriately considered in their Facility Ratings analysis and documentation. If your organization would like to learn more about Facility Ratings compliance assurance and controls, or if you’d like to have your Facility Ratings program reviewed, please contact Dale Zahn at or (262) 436-4116.


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