NERC report summarizes key findings from Level 2 Recommendations to Industry
Inverter-based resources (IBRs) continue to become an increasingly prominent part of the generation resource mix. Accurate and validated modeling of IBR resources is essential for maintaining grid reliability. A 2024 NERC report, Inverter-Based Resource Model Quality Deficiencies Alert, highlights industry-wide challenges that require greater coordination and shared responsibility among Generator Owners (GOs), Transmission planners (TPs), and Planning Coordinators (PCs). Many of the current IBR modeling issues stem from a lack of ownership, accountability, and technical rigor.
Published in April 2025, the Aggregated Report on NERC Level 2 Recommendation to Industry highlights issues with model quality, insufficient verification or validation, and not enough engagement with modeling best practices. This has led to inaccurate power system studies and poses risks to system operations.
The NERC report found that some generator models used in planning studies fail to accurately reflect real-world behavior under system conditions, partly because they are not always validated against commissioning data or performance data from disturbance events. Some GOs primarily depend on Original Equipment Manufacturers (OEMs), consultants, or vendors to provide modeling data and develop models, but the report notes that there is often limited follow-up or quality assurance before these models are submitted to TPs or PCs. This allows errors to go undetected.
IBR models have been submitted to planners and coordinators with default parameters or values that do not reflect the actual plant configuration, control settings, or expected performance. In some cases, the IBR controls lacked tuning, and the models used outdated templates or failed to include site-specific details, configurations or protection logic. All these details are important to continued reliable operation of the power grid.
Two thirds of the protection settings implemented by the GO respondents were configured below the maximum capability of their inverters. This creates an artificial limitation of ride though capability decreasing the IBRs ability to withstand transients and faults. Approximately twenty percent of the IBR facilities that responded are operated with a “triangle” capability curve, limiting the IBRs power factor to 0.95 at all levels of operation. As a result, a substantial portion of IBR reactive power capability remains unused and impacts the operation, efficiency and stability of the bulk power system.
Accurate and validated IBR modeling is fundamental to the reliable operation of the bulk power system. Poor modeling practices erode confidence in planning studies, increases the risk of misoperations, and compromise system resiliency. Enhancing modeling requirements and study procedures will be further addressed in an upcoming level 3 alert from NERC to further reduce these risks and mitigate the deficiencies.
– Eric Graftaas, MRO Principal Power Systems Engineer