▶️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
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.
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.
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.
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.
