NERC Prioritizes Inverter-Based Resources for Future Standards Development

As inverter-based resources found in wind and solar generation technologies continue to rapidly penetrate the U.S. power delivery system, NERC remains focused on managing the potential reliability consequences. Building on NERC’s 2019 analysis of several major power disturbances and its report outlining the risks of inverter-based renewable energy resources, the Inverter-Based Resources Task Force (IBRTF) recently issued an industry survey, the results of which will serve as a roadmap for future standards or guidance activities.

Priorities for Existing or Future Activity

The survey results reveal the collective industry opinion regarding the priority of the NERC activities as follows. Note that a number of these efforts are currently underway:

1. Reliability Guideline: BESS and Hybrid Plant Performance, Modeling, and Studies (underway)
2. Reliability Guideline: Electromagnetic Transient (EMT) Modeling and Simulation (underway)
3. Follow-Up and Tracking: Positive Sequence Modeling Issues (underway)
4. Technical Report: Energy Transition to High IBR Penetrations (underway)
5. White Paper: TP/PC Stability Criteria in High IBR Penetrations (possible future)
6. Technical Report: BPS Protection System Impacts from Increasing Penetrations of IBRs (underway)
7. White Paper: Grid Forming Technology (possible future)
8. White Paper: Frequently Asked Questions for Newly Interconnecting BPS-Connected Inverter-Based Resources (possible future)
9. White Paper: Technical Challenges with the Existing BES Definition Criteria (possible future)
10. White Paper: Utilizing Overbuilt IBRs for Frequency Response (possible future)

Additional Topics of interest to the industry

As part of its survey, NERC asked an open-ended question to identify any additional topics that should be considered by NERC in the future. The following items are listed in terms of the priority of those responses:

1. Recommended performance requirements of power oscillation damping controls
2. IBR and recommended ways to develop interconnection requirements around these controls.
3. Modeling, screening studies, and detailed simulation methods for studying potential risks of subsynchronous control interactions and subsynchronous resonance with increasing penetrations of IBR.
4. Guidance around IBR commissioning and model development/validation during and after plant commissioning.
5. More detailed guidance and case studies regarding modeling, studies, and performance requirements in areas of low short-circuit strength
6. Standardized IBR controls and capabilities
7. New simulations methods (e.g., hybrid simulations or co-simulations) that combine positive sequence simulations with short-circuit and electromagnetic transient simulation tools
8. Cybersecurity implications of growing levels of inverter-based resources on the BPS
9. Inverter-based resource modeling for short-circuit studies, and considerations for short-circuit related standards requirements where advanced modeling practices are needed (e.g., PRC-026-1)
10.  Additional specifications for criteria or requirements such as sub-transient versus transient performance requirements, protection of synchronous generation during ramping periods, and minimum reserve requirements with increasing penetrations of IBR
11. Impacts of new distribution-connected technologies (i.e., Internet of Things, electric vehicles) and growing distributed energy resource penetrations combined with growing penetrations of Bulk Power System (BPS) connected IBR.
12. System model validation for past disturbances such as the Blue Cut Fire, Canyon 2 Fire, or Palmdale Roost disturbances.

TRC transmission and distribution owner clients are advised to carefully review these priorities related to generation interconnection requirements for new inverter-based generation resources. TRC generation clients are also advised to review these same documents to understand NERC’s future direction a potential impact on compliance and generation interconnection requirements.  TRC can assist your company with any related implementation issues whether your company is a generation owner or a connecting transmission, distribution service provider.

Resources:

• NERC BPS-Connected Inverter-Based Resource Priorities Whitepaper – June 2020
• Transmission Engineering 
• Power Systems Studies
• Integrated Distribution Planning 
• NERC Compliance Support
• Electric Utilities Solutions

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