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.
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.
