Meeting Summary - 07/12/24 IBRWG Meeting

1 - Antitrust Admonition - Julia Matevosyan

2 - Preliminary Advanced Grid Support Inverter-Based ESR Functional Specification and Test Framework - ERCOT/Electranix - Fred Huang

• Update on status from a few months ago; Electranix contracted as SME consultants.
• Project aims to identify capabilities, performance, and test framework for grid forming technologies suitable for ERCOT.
• Collaboration with Electranix; Andrew from Electranix to present the project's summary.
• ERCOT staff working in parallel on assessment from the grid's stability and performance perspective.
• Discussion on adoption of new technology/features in the ERCOT grid.

2.1 - Advanced Grid Support BESS Functional Specification and Test Protocol - Andrew Isaacs

• Introduction
• Presentation by Andrew Isaacs
• Collaborative effort between consultants and the ERCOT team.
• Focus on testing grid forming battery energy storage systems (BESS).
• Grid Forming Battery Technology
• Technical functional specification and test framework developed.
• Four EMT models from commercial devices extensively tested.
• Functional definition and specification approach, avoiding specific control topologies.
• Project Team and Background
• Involved engineers from both consulting and ERCOT sides.
• Team members from operations, planning, and ERCOT personnel acknowledged.
• Previous experience with grid forming specification since 2021.
• Grid Forming vs. Grid Following
• Explanation of grid forming as maintaining a constant voltage phaser at the inverter terminals.
• Grid following tightly controls active and reactive currents by synchronizing with the external grid.
• Comparison of responses in island and grid-connected systems.
• Benefits of Grid Forming Technology
• Better performance in weak systems.
• Damping of subsynchronous frequencies.
• Enhanced voltage and frequency support.
• Testing Framework
• Four main test benches: Variable Impedance System (Single Machine Infinite Bus) , Double Battery, Variable Impedance System + series capacitor , and Perturbed Voltage Source.
• Tests evaluate grid forming characteristics, stability, energy response, and damping.
• IEEE 2800 compliance considerations.
• Specific Tests and Objectives
• Examples of tests: Loss of last synchronous machine, RoCoF tests, SCR step down with fault, angle step change, series compensation step test, energy response test, and frequency scan tests.
• Some tests designated as pass/fail, others informational.
• Tests designed to push inverters to their operational limits.
• Challenges and Observations
• Discussion on potential model improvements for grid following devices.
• Interactions between grid forming and grid following devices not included in mandatory tests.
• Importance of headroom and practical considerations for energy response.
• Conclusion and Follow-up
• Grid forming batteries show promising stabilization benefits.
• Ongoing collaboration and future work anticipated.
• Summary of OEMs’ performance and validation through tests.

3 - ERCOT Advanced Grid Support Inverter-Based ESR Assessment and Adoption Discussion - ERCOT, All - Fred Huang

• Presentation from Fred Haung
• ERCOT is in the early stages of assessing new inverter-based energy storage resources (ESRs) with advanced grid support capabilities.
• Feedback and industry collaboration are highly encouraged to improve the process.
• Upcoming proposals aim to set standards for advanced grid support inverter-based ESRs, focusing on functionality and performance.
• Initial focus is on voluntary adoption of new standards, with mandatory adoption considered for the near future.
• ERCOT has been in dialogue with various industry original equipment manufacturers (OEMs), including those from the wind and solar sectors, to gain insights and support.
• Preliminary results indicate that inverter-based ESRs can enhance grid stability with minimal hardware impact.
• Studies show positive impact on system stability, potentially increasing limits for existing Grid Transmission Constraints (GTCs).
• Considering global trends and activities, ERCOT aims to adopt advanced grid support inverter-based ESRs starting with energy storage and expanding to wind and solar.
• Tools and models will need to be accurately coordinated and monitored for optimal grid support.
• Future steps include submitting a revision request for adoption and potentially creating a new ESR support framework.
• Acknowledgement of collaborative efforts with academia and internal ERCOT teams in progressing this initiative.

Questions

Ryan Wu: Are there any considerations about the increased risk of islanding with grid forming adoption?

Answer: Currently under internal discussion with an emphasis on operating ERCOT as a single grid.

General Question: What's the timeline for protocol language adoption?

Answer: Plan to have protocol language by end of 2024, with potential for further group discussions before formal submission.

General Question: Is the work on specifications and testing finalized?

Answer: Electronics recommendation used as primary reference; internal reviews and potential adjustments based on feedback are ongoing.

5 - Draft DWG Procedure Manual Edits - John Schmall, Jonathan Rose - ERCOT, All

• Follow-up presentation regarding NOGRR245 and IEEE 2800 changes.
• Changes impact the DWG procedure manual, specifically voltage ride-through requirements.
• DWG procedure manual is a key document for model quality testing (MQT).
• Edits to the procedure manual incorporate new voltage ride-through curves from NOGRR245.
• Updated manual is available on the ERCOT Dynamics Working Group webpage.
• Presenting and seeking approval for language updates at the August ROS meeting.
• Reconciling old legacy curves with new preferred curves in the updated manual.
• Addressing modeling of switch shunts, transformer tap controllers, and testing for low/high voltage ride-through (LVRT/HVRT).
• Requesting additional details in the table format to document equipment capabilities.
• Ensuring alignment of provided models with actual operational practices and capabilities.
• Next steps: ERCOT intends to review comments from stakeholders before moving forward.

Key Comments:

• Request for stakeholders to provide comments within a week, potentially extending the deadline to allow more time for review.
• Stakeholders expressed concerns over time for reviewing complex changes.
• ERCOT agreed on extending the comment deadline to around July 24, with a target post date by July 26.
• Discussion on when new ride-through profiles from NOGRR245 would be effective.

Questions Addressed:

• Clarification on minor voltage changes and active power injection requirements.
• Details about the speed and control of transformer tap settings and initialization scripts.
• Requirement to model transformer tap controllers despite their time delay.
• Acknowledgement of the implementation date and procedural nuances for NOGRR245.

6 - Other Business - All

• Steven Solis deferred his item to the next meeting.
• There was a discussion item from March ROS related to reclosing close to IBRs. This will be discussed in the SPWG meeting on the 17th and will be brought to the August agenda.
• A market notice has been issued about switching to a single resource battery model starting from August 6, which will also be discussed in the next IBRWG meeting.
• No other business items were brought up.

7 - Adjourn