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Performance Issues Related to Inverter Based Resources

NERC report shares findings to drive improvement of Solar, Wind and Battery Storage

NERC issued a Level 2 alert, Inverter-based Resource Performance Issues, in March of 2023 after the ERO Enterprise received numerous event reports that showed deficiencies in Inverter Based Resource (IBR) performance during grid events. The alert provided recommendations for Generator Owners of IBR facilities to improve performance. The alert also emphasized that modeling and study inaccuracies exist in solar, wind and battery storage systems, with the greatest performance and modeling issues in solar resources.

Entities were asked to respond to the Level 2 alert and provided additional information and data for NERC to assess. The following are some of the initial key findings:

  • Voluntary recommendations from NERC guidelines related to IBR’s are not being implemented.
  • Generator Owners did not have fundamental IBR facility data settings readily available and are relying on the Original Equipment Manufacturer for the information.
  • 5200 MW of Bulk Electric System (BES) IBRs have voltage and frequency protections settings that are set within the NERC PRC-024 “no trip zone”.
  • One out of four IBR facilities use a fault ride through mode that does not support BES reliability.
  • One third of the entities’ IBRs use only a portion of the full reactive capability curve. The resources are set to use a smaller “triangle” portion of the capability curve (limited to 0.95 power factor at all power levels).

The initial findings indicate that Generator Owners and Generator Operators of IBRs are not implementing voluntary recommendations from NERC guidelines and are only performing the minimum requirements in FERC Orders, NERC Reliability Standards, and regional requirements. This is creating a risk to reliability of the North American bulk power system. Improvements are necessary to ensure that IBRs meet more than the minimum requirements and can be relied upon like synchronous generation.

Based on NERC’s assessment of the data provided by registered entities, the following activities address the key findings.

  • The NERC Inverter Based Resource Performance Subcommittee (IRPS) will develop a standard authorization request (SAR) to revise FAC-001 to include uniform IBR performance requirements.
  • NERC Reliability Standards Projects, 2020-02 Modifications to PRC-024 and 2023-02 Performance of IBRs will be developed to implement performance and post-disturbance requirements and address the existing performance issues. (These projects will lead to a more reliable IBR fleet.)
  • NERC will issue a level 2 alert in 2024 to gather modeling and study data from Generator Owners and Transmission Providers.

Additional details and information can be found in the NERC Inverter-Based Resource Performance Issues Public Report 2023

Eric Graftaas, Principal Power Systems Engineer, Midwest Reliability Organization