Meeting Summary – 09/16/24 IBRWG Meeting

1 – Antitrust Admonition Julia Matevosyan

2 – DWG Procedure Manual S.-W. Kang

• ERCOT appreciates stakeholder support and addressed all comments on the DWG precision manuals.
• Draft DWG procedure manual posted on DWG website.
• PUCT decision on NPRR245 expected in September; effective date likely October 1.
• ROS approval sought on October 3, previously planned for September.
• Updated DWG manual available on the website as a draft for familiarization.
• ERCOT updated PMV and DMV tools for NPRR245 writethrough test.
• Tools are linked in previous meeting presentations and ERCOT model quality guide.
• Confirmations received from Jonathan on PMV and DMV tool updates with latest NOGRR245 test proposals.

3 – NERC Standards Update FERC Order 901 M. Henry TRE

• Brief update on NERC standards related to FERC order 901
• FERC directives to NERC in October 2023 to address IBR integration challenges
• Four focus areas: data sharing, model validation, planning, operational studies, IVR performance requirements
• Milestone 2 projects to be completed by November 4
• Three projects involved in Milestone 2
• Details on the first project: Disturbance monitoring equipment (2021-04) leading to PRC-028-1 standard
• PRC-024 version 5 IBR-related material moved to PRC-029, consensus issues
• Technical Conference held by NERC to gather feedback on PRC-029
• Workshop findings: difficulty meeting requirements with older equipment, technical challenges, and OEM feedback
• New standard PRC-030 asking entities to evaluate and mitigate issues
• New standards expected to be issued for final ballot
• NERC board may step in if consensus is not reached

Questions Asked:

• Name: John Schmall
  Question: Who is responsible for drafting the revised standard for PRC-029?
  Answer: NERC staff most likely driving it with the standards committee.
• Name: Ken Donohoo
  Question: Clarification on proposed standards exceeding IEEE 2800 and concerns over legacy equipment
  Answer: Acknowledgment that proposed standards go beyond IEEE 2800; consideration for legacy equipment being discussed.

Next Steps:

• NERC to issue new standard for ballot with a quick turnaround
• Further outreach and discussions to address concerns
• Update on implementation timelines after FERC approval

4 – Draft Proposal for Advanced Grid Support Energy Storage Resource F. Huang ERCOT

• Fred Huang from ERCOT provided an update on a planned revision request.
• Three key documents were posted: draft NOGRR, draft PGRR, and the pace framework report.
• Electronics consultant recommended eleven tests for gridforming technology; narrowed down to seven proposed test requirements.
• Potential impact on the grid includes improved system voltage and frequency response during events, and increased stability in areas with advanced grid support energy storage.
• The proposal mainly focuses on energy storage resources currently but may extend to other inverter-based resources like wind and solar in the future.
• ERCOT aims to reinforce system reliability and support, responding to the growing penetration of inverter-based resources.
• New requirements will apply to energy storage with SGIS agreements signed on or after April 1, 2025.
• Seven model quality tests to be introduced for energy storage resources to assess and verify advanced grid support.
• The proposed tests include:
  • Flat start test
  • Small voltage disturbance test
  • Large voltage disturbance test
  • Frequency change and inertia response test
  • System strength test
  • Phase angle jump test
  • Loss of synchronous machine test
• The pace framework report elaborates on the functional specifications and the setup for the seven proposed tests.
• Future directions include exploring similar requirements for wind and solar resources.
• Further details may be presented in a work session in the next IBR working group meeting.
• Stakeholders are encouraged to provide feedback before formal submission in October.

5 – PFR from IBRs under “Deep” Curtailment M. Cova Acosta Vestas, Nick Miller Hickory Ledge, All

• Miguel Acosta from Vestas highlighted key concerns regarding primary frequency response (PFR) from IBRs during deep curtailment.
• Current frequency response standards like BAL TRE and its four defined zones were discussed.
• Main issues identified: IBRs’ failure to respond to under-frequency events when high curtailment or no power production exists.
• Explanation of turbine operations during full curtailment and the time it takes to resume active power production.
• ERCOT’s expectation is for primary frequency response within 16-60 seconds, which isn’t met by turbines in a fully stopped state.
• Miguel suggested two solutions: listing this situation as an exemption and creating realistic expectations for turbine capabilities in centralized systems.
• Potential improvement with realistic telemetry data to facilitate grid operator expectations.
• Nick Miller and other participants discussed the impact of NTON/NTOFF telemetry in relation to turbine readiness and its effect on grid support during frequency events.
• The impact of mechanical wear and tear due to frequent start-stop cycles of turbines was highlighted.
• A second limitation discussed was the technical minimum operating points and the need to configure plants to avoid turbines frequently pausing and restarting due to minor frequency deviations.
• Potential solutions include setting a low sustained limit above zero or implementing filtering mechanisms to handle small frequency deviations.
• Need for understanding how other OEMs handle frequency sampling and the importance of forums for open discussion.
• A final enhancement suggestion to improve IBR response, focusing on faster response capability and lack of inertia in IBRs.
• Questions from participants covered issues such as commercial considerations, impact on models, and specific vendor differentiation.

6 – NOGRR245 Update S. Solis ERCOT

• NOGRR245 is expected to be reviewed by the commission this month, with hopes for approval.
• One of the commissioners had previously commented on monitoring NERC activities. Conversations with FERC staff about timelines were also noted.
• If regional needs exceed NERC standards, it’s acceptable. There’s a history of avoiding duplication of NERC rules but adapting them to meet ERCOT region requirements.
• Internal drafts exist. Feedback from the commission will shape the next set of language. A new NOGRR will be submitted soon after approval.
• Discussions will likely be held in the IBRWG for a month, but crucial conversations will occur in ROS and TAC forums.
• Updates will be provided monthly to the IBRWG to keep all parties informed of developments.
  
  

7 – RoCoF and Phase Jump Measurement Discussion M. Cova Acosta Vestas, S. Solis ERCOT, All

• Discussed the importance of measurement methods for Rate of Change of Frequency (RoCoF) and phase angle jumps for determining protection system responses.
• Previous presentations and literature indicate that measurements during transients/faults may not be reliable for RoCoF monitoring and tripping.
• IEEE 2800 suggests an averaging window of at least 0.1 seconds, but recent events showed this might not be sufficient.
• Discussion on adopting an appropriate averaging window for the region, with ERCOT suggesting 0.5 seconds.
• Highlighted that phase angle jumps should not trip during faults and require a different consideration for averaging windows.
• Lacking feedback from generator owners, prompting further discussions and feedback collection.
• Vestas shared their internal process for frequency calculation using LabVIEW software, highlighting the need to understand different measurement methods.
• Concerns raised about moving averaging windows and how different calculation methods might affect RoCoF measurements and subsequent actions.
• Emphasis on standardizing methods for calculating frequency and RoCoF to avoid different measurement expectations and improve coordination.
• Understanding how frequency readings are processed from instantaneous waveforms is critical before determining new standards.
• Comments on practical difficulties related to aligning different manufacturers’ measurement methods.
• Suggestion for OEMs to align with ERCOT’s measurement methods to ensure consistent communication and compliance.
• Need for transparency in methodology used by ERCOT for its RoCoF conclusions based on available PMU data.
• Discussion on the potential pros and cons of extending or reducing the moving average filter window.
• Importance of standardized methodologies to avoid discrepancies and ensure accurate RoCoF measurements across different equipment.
• Planning a working session to further discuss and define methodologies and implementations for consistent measurement standards.
• Acknowledgment of the need to progress towards solutions in a timely manner to align with implementation timelines.