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Regulatory Updates

NERC Prioritizes Inverter-Based Resources for Future Standards Development

Dylan Achey and Jim Whitaker, PE | October 19, 2020

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.


About TRC

TRC’s approach to power system planning and design balances solutions that incorporate the appropriate standards, regulatory requirements, best practices, operational goals and budgets. We help utilities to perform complex studies and advanced analyses in areas such as calculating optimal power flow, nodal/dynamic hosting capacity, DER placement, storage dispatch and investment optimization in a matter of minutes, even for large batches of networks. We also support utilities to improve, standardize, and automate advanced planning processes.

Our power system experts help you stay ahead of changing regulatory expectations because they stay engaged with the regulatory process and know how to plan, design and install programs that address your financial, technical and scheduling goals including compliance with changing NERC Operations and Planning standards and guidelines.

This regulatory update is a service to TRC’s utility clients, helping keep you informed of issues that impact your company’s electric system security risks along with related topics regarding future regulatory developments to help you achieve your company’s business goals.

Dylan Achey

Dylan Achey is TRC’s Manager of Generation Engineering Services. He has been leading the effort with TRC generation clients on evaluating and providing updates/information so that clients can meet applicable NERC standards. His highly technical staff perform NERC compliance standard evaluations as well as studies for both generation and transmission clients that need assistance on technical issues concerning NERC compliance. Contact Dylan at

Jim Whitaker, PE

Jim Whitaker, PE is Supervisor of Power Systems Studies at TRC. He has over 30 years of experience in Transmission and Distribution Planning, and Substation, Transmission and Distribution Engineering. His Transmission Planning projects include coordinating joint/regional 10-year transmission plans, generator interconnections, regional system assessments, as well as NERC compliance studies. His projects have included studies for both Utilities and Project Developers across the United States in the Eastern and Western Interconnection transmission systems as well as ERCOT. Prior to joining TRC, Jim worked for Xcel Energy, Peak Power Engineering, Tucson Electric Power and Virginia Power. Contact Jim at

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