The North American bulk power system (BPS) is currently undergoing substantial transformation in technology, design, control, planning, and operation, and these changes are occurring more rapidly than ever. Technological advances in inverter-based resources (IBRs) are having a major impact on electric generation, transmission, and distribution systems. While the integration of IBRs connected to the BPS contribute to a resilient and sustainable energy future, IBRs also introduce significant risks to the reliability of the grid. This rapid evolution continues to pose challenges for grid planners, operators, protection engineers, and various other stakeholders within the electricity sector.
The North American Electric Reliability Corporation (NERC) conducted an analysis of ten significant BPS disturbances that resulted in substantial and unforeseen decreases in the output of IBRs since 2016. Collectively, these disturbances accounted for nearly 15,000 Megawatts[1] (MW) of unexpected reductions in IBR output, with around 10,000 MW occurring between 2020 and 2024. The rise in IBR-related incidents corresponds with an increase in the penetration of IBR on the BPS.
Two primary factors contributing to these occurrences are inadequate modeling and insufficient study practices for evaluating performance of IBR resources.
On June 4, 2024, NERC issued a Level 2 Alert: Inverter-Based Resource Model Quality Deficiencies.
The alert was sent to all Generation Owners (GOs) of Bulk Electric System (BES)-connected Inverter-Based Resources (IBRs), as the identified modeling deficiencies, best practices, and recommendations are relevant to all IBR technologies.
The level of complexity in IBR modeling requires enhancements in the core principles of dynamic modeling to effectively represent the performance of IBR plants.
The alert was also shared with Transmission Planners (TPs) and Planning Coordinators (PCs) to offer suggestions that can be adopted to improve existing modeling practices. TPs and PCs are expected to respond to a series of questions within the NERC alert system. GOs of IBRs will be required to fill out an additional Data Submission Worksheet.
Initial acknowledgement of receipt was required by June 11, 2024, Midnight Eastern Time via the NERC Alert System. Responses to the 15 questions in the alert were initially required to be submitted by September 2, 2024, Midnight Eastern Time. NERC has since granted a two-month extension for the completion of responses to the Alert. The revised deadline for submitting approved responses is now November 1, 2024.
Notable dates:
- Initial distribution of the Level 2 Alert was June 4, 2024.
- Acknowledgement of alert receipt was required by Midnight Eastern Time on June 11, 2024.
- Reporting is required by Midnight Eastern Time on November 1, 2024.
- This will include responses to alert questions, any supporting documentation, as well as approvals of the responses from appropriate entity personnel.
Questions on this Alert should be directed to Reliability Analysis.
– Max Desruisseaux, MRO Principal Power Systems Engineer
[1] A megawatt is a unit of measurement for electricity that is equal to one million watts.