Meeting Summary - 02/21/2025 IBRWG Meeting

▶️1 - Antitrust Admonition / Announcement by Katie Rich

• Katie Rich (Vistra) reminded attendees about the direction from ROS regarding NOGRR272 and PGRR121, and that ROS decided to table these items pending further policy direction and review of a new NPRR.
• It was suggested to skip the agenda items not directly related to the goals advised by ROS, but some members prioritized getting technical insights from OEMs.
• Katie emphasized that today's input would not feed back into ROS or aid in making policy decisions.
• Caitlin Smith (Jupiter Power), although an interested party, noted that working groups can pursue relevant topics and that sharing information is acceptable, given it won't directly influence the NOGRR.
• There was a consensus to proceed with OEM speakers discussing capabilities without delving into specific language of PGRR and NOGRR.

▶️2 - PE’s GFM Capabilities and Perspective on ERCOT’s Advanced

• Stephen Giguere, VP of Engineering at Power Electronics (PE), discussed grid forming (GFM) capabilities, highlighting the challenges and advancements in the technology.
• Power Electronics, a Valencia, Spain-based company, focuses on solar and energy storage inverters, with significant work being done in grid forming, primarily in Australia and the UK.
• A key challenge is the extensive modeling required before project approval, which can take up to 18 months.
• Traditional inverters operate on constant current, but grid forming requires a shift to a constant voltage system, allowing better response to grid events.
• Growth in renewable energy is pushing the need for more advanced grid forming systems, evidenced by historic moratoriums on solar due to high renewable penetration.
• PE’s approach involves converting existing inverters to support both grid forming and grid following modes with minimal hardware changes, using a hardware kit to enhance system LC filters.
• Current models and implementations in Australia provide valuable lessons for potential adoption in the US.
• For grid forming, a penalty exists with a 90% output rating versus full output in grid following, due to the emphasis on overload capability and reactive power support.
• PE has various demo sites in operation, showcasing their technology in both grid forming and following modes.
• Stephen Giguere acknowledged questions and emphasized Power Electronics' capability to provide PSCAD and PSSE models under NDA for testing.
• Discussions included clarifications on inverter ratings and grid forming project tracking, highlighting PE's exclusive focus on their projects.

▶️3 - SUNGROW’s GFM Capabilities Perspective on ERCOT’s Advanced Grid

SUNGROW GFM Capabilities Perspective on ERCOT AGS-ESR_20250221 to ERCOT.pdf

• Introduction: Ling Chen, manager of modeling at SUNGROW USA, presented SUNGROW’s grid forming (GFM) capabilities and technologies, particularly their inverters' modeling and practical applications within ERCOT.
• SUNGROW's inverters utilize Virtual Synchronous Generator (VSG) technology, enhancing the response to grid voltage and frequency disturbances compared to grid-following inverters.
• GFM technology improves inverter responses to frequency disturbances, enhancing system stabilization.
• Discussed the low voltage ride-through capability of inverters under weak grid conditions, and how GFM technology aids in better stabilization and reduced oscillations.
• GFM's capability to help with oscillation damping improves grid stability and power transfer capacities.

• SUNGROW has developed second-generation GFM inverter models, which successfully passed multiple test scenarios as per ERCOT guidelines.
• Tests included flat ride-through test, phase angle jump test, and other frequency and oscillation response behaviors showing promising results.
• Real-world applications of SUNGROW’s GFM technology include projects in Indiana, USA, and Saudi Arabia, among others, showcasing various grid-forming configurations and capabilities.
• Daniel Friberg mentioned incorporating GFM does not require additional hardware upgrades but might entail software upgrades and modeling efforts.
• Stephen Giguere added that increasing costs could be around $4,000-$5,000 for additional components like filters.

▶️4 - NOGRR272 & PGRR121 Comments Discussion

• Not discussed

▶️5 - Including HRL as an aggregated value of a defined IRR Group

HRL Grouping units- Acciona Energy-2.21.2025.pdf

• Ismael Moral Diaz from Acciona Energy presented potential improvements to enhance power injection into the grid using installed capacity.
• Acciona Energy operates globally with extensive experience in renewable technologies.
• Acciona Operates five wind facilities, two PV plants, and one BESS in ERCOT.
• Issues were identified between the planning and operational phases of power generation, particularly regarding HRL (High Reasonability Limit).
• Currently, ERCOT focuses on individual unit HRLs, potentially leading to loss of power injection capacity during operations.
• The proposal suggests aggregating HRL for grouped resources to maximize renewable energy utilization without affecting ERCOT's planning process.
• Group HRL would allow plants to operate at maximum capacity even if individual units are limited by clouds or other factors.
• Such a change is compliant with ERCOT regulations and doesn't affect contracted power requirements.
• The proposal received support from a plant systems integrator, Seth Maslowski, who shared insights on current group resource functionalities.
• Next steps involve further discussions and possibly submitting a formal proposal to ERCOT.

▶️6 - NERC Updates

250221 IBRWG_PRC029_NOGRR245.pdf

• Mark Henry from Texas RE provided updates on NERC standards, specifically PRC-029 and NOGRR245.
• Discussion focused on the ride-through standards for inverter-based resources (IBRs), defining what IBRs are, and the applicability of standards.
• PRC-029-1 and PRC-029-4 are currently at FERC, open for comments until March 24th. It addresses ride-through conditions, including faults and voltage issues.
• Comparison made between PRC-029 and NOGRR245 standards, highlighting differences in requirements for maximum capability and exemptions.
• Discussion of requirements for IBRs to maximize capability, with existing differences in language between NERC and ERCOT standards.
• PRC-029 is consistent with IEEE 2800-2022, ERCOT preserves a portion of the legacy curve for low voltage conditions under NOGRR245 standards. Otherwise it is the same curve.
• Frequency ride-through requirements and the inclusion of additional steps by ERCOT were discussed.
• Exemption processes differ between NERC and ERCOT, with specific conditions outlined by NERC.
• Updates on generator registration programs affecting resources connected at certain voltages and capacities in Texas.
• Discussion of new requirements affecting solar with capabilities of 20 MW or higher under NERC's generated availability data systems.
• Feedback from stakeholders indicated changes and clarifications in the PRC-029 exemption processes to include both voltage and frequency requirements.

▶️7 - Other Industry Updates

ERCOT_IBRWG_Industry_Updates_022125.pdf

• Salt River Project (SRP) in Arizona released best practice specifications and test procedures for grid forming battery energy storage systems, effective from 02/14/2025, driven by the anticipated high percentage of inverter-based resources (IBRs) by 2030.
• Grid forming battery storage is deemed necessary for reliability and stability in SRP's system, especially in weaker grid areas, and will be required on a case-by-case basis.
• SRP recognizes the need to comply with multiple IBR performance specifications and allows exemptions for challenges in meeting the standards, partly based on IEEE 2800-2022.
• A collaborative study with ATC in Wisconsin and Michigan evaluated grid forming battery benefits in a realistic system, concluding it as a 'do no harm' solution that interoperates with existing grid devices and doesn't cause reliability issues.
• The study demonstrated successful interoperability across multiple OEMs and suggested that grid forming can help defer other options like synchronous condensers.
• An ESIG spring workshop in Austin will feature technical sessions on oscillation, stability, and NERC projects relevant to the group's focus.
• Large load integration is highlighted as a hot topic, despite not being directly relevant to the current scope.

▶️7.1 - DWG and IBRWG Collaboration

Dwg_Procedure_Manual_Revision_23_draft.pdf

• Presentation of the procedure manual revision for DWG, emphasizing collaborative updates from ERCOT operations and Dynamics for planning.
• Major update includes a restructured table in the initial section identifying technology types, required software, and relevant sections for each test.
• Introduction of new sections for AGS ESR outlining changes in tests and performance requirements compared to non-AGS ESR tests.
• Emphasis on the unchanged requirements like flat start and voltage ride-through but noting new presentation and readability improvements.
• Details on test structures covering description, setup, performance criteria, and acceptable performance from sections 3.1.5.11 onwards.
• Introduction of new tests including voltage test, frequency change, inertia test, system strength test, phase single jump, and loss of the last synchronous machine test.
• Amendments to unit model validation language to ensure AGS ESR models meet new test requirements and settings.

▶️8 - AGS ESR Model Quality Tests - 12:30 p.m.

ERCOT Response to Comments on AGS-ESR Test Requirement_02-2025 IBRWG.pdf

Frequently Asked Questions-AGS ESR_02-2025 IBRWG.pdf

• Focus remained on technical items; policy specifics were avoided.
• Stakeholders' comments were mostly addressed previously, but a FAQ document is available above.
• Discussion on plant control and the necessity of including relevant controls to represent dynamic characteristics.
• Clarification that model quality tests focus on ESR response at the POI and are a preliminary step in the interconnection process.
• ERCOT aims to cover adequate test scenarios; the seven specific tests provide a solid basis for AGS-ESR validation.
• Questions from Stephen Solis about planning study assumptions and policy were noted but sidestepped as they relate to NOGRR272.
• No mandate from ERCOT on maintaining any ESR headroom in planning studies.
• Emphasis on model testing, focusing on whether ESR can provide advanced characteristics.
• Exploration of fault types and scenarios in testing; it's a required process for IBRs.
• Loss of a synchronous machine test was discussed with a focus on appropriate power response.
• Clarification on the specific criteria for plant oscillation and converter control requirements.
• Phase angle jump test criteria details were discussed, including clarification on Tesla's inquiries.
• Discussion on the peak active power change and the assumptions regarding 10-degree and 25-degree angle jumps.
• Clarification provided on test criteria and the flexibility available in meeting ERCOT standards.
• A graph was presented to demonstrate theoretical initial p values against various plant impedances.
• Tesla's concerns about one-cycle rise time criteria were addressed.
• Acknowledgment that criteria apply under all conditions; language in the DWG manual was updated for clarity.
• FAQ document, slides, and redline documents have been posted on the IBR working group website for review.
• Steven emphasized technical queries related to MQT, referencing a December 2021 NERC paper for further consideration.

▶️9 - Adjourn