IPWG: Proposed IBR Performance Requirements (20230620)

AES Clean Energy appreciates the opportunity to provide feedback on MISO’s proposed implementation of specific clauses of IEEE 2800 standard, and offers the following responses to MISO’s specific technical questions:

1.What is the preferred default setting for enter service intentional adjustable minimum delay and duration of enter service period? (Slide 9)

AES Clean Energy does not oppose the default settings proposed by MISO for enter service criteria. These values align with our current operational practices.

2. What specific concerns, if any, could arise from MISO’s proposal to define the Reference Point of Applicability (RPA) as the Point of Interconnection (POI)?

AES Clean Energy does not oppose the RPA as the POI but recommends that the RPA be more specifically defined as the high side of the GSU, which would make it easier for generators to comply with these standards.

3. MISO’s proposal to implement the Tariff changes for GIA’s resulting from DPP-2022-Cycle interconnection requests

AES Clean Energy does not oppose MISO’s decision to implement these changes on a forward basis and is optimistic that projects in DPP-2022-cycle should have sufficient time to become compliant with the new standards. AES Clean Energy expects projects in this cycle to reach COD between 2027-2029, which should be a sufficient runway. However, AES Clean Energy recommends that MISO offer some flexibility to delay implementation if generator owners are able to provide sufficient evidence that equipment manufactures do not offer products that are IEEE 2800 compliant.

Clean Grid Alliance Comments on Inverter Based Resource Requirements
July 14, 2023

Clean Grid Alliance appreciates the opportunity to provide feedback to MISO on the proposed IBR requirements.

Timing of Implementation: 

Several actions should be completed prior to implementation of new IBR requirements: 

1. Finalization of the IEEE 2800.2 standard 
2. Prospective implementation with advance notice prior to a DPP queue window closing
3. Transparent documentation that a majority of IBR manufacturers can meet the standards
4. Demonstration that MISO has explored deployment of alternative methods of addressing any IBR reliability issues/concerns such as through grid enhancing technologies and transmission improvements/upgrades

The timing of the implementation of any new policy or standard is an important factor to consider. For example, if MISO implements a new IBR standard and none of the IBR  manufacturers (or only a select few) are able to meet them, it will have significant impacts on the MISO market including preventing viable/ready projects from reaching COD. Stakeholders are looking to MISO for guidance in sharing a publicly available document demonstrating that a majority of IBR manufacturers can meet the new standards, to ensure that MISO itself will not be preventing generation interconnection projects from reaching COD by implementing policy that cannot be met. 

Additionally, new IBR requirements should only be implemented in forward DPP cycles, as projects currently queued up in the DPP 2022 cycle have already submitted engineering models and would face material modification and potentially supply issues in trying to change equipment after studies have officially been kicked off. New standards should be implemented with sufficient notice prior to a DPP queue cycle closing to similarly avoid market impacts and additional administrative burdens on MISO staff. 

Finally, implementation of new IBR requirements should be planned for after finalization of the IEEE 2800.2 standard for testing and verification. Otherwise, there will be issues with consistency among individual projects, particularly around self-certification and collection of operational data.

Sincerely, 

Rhonda Peters, Ph.D.
Technical Consultant for Clean Grid Alliance

NG Renewables notes that the IEEE 2800 has not been finalized, and that changes developed during this stakeholder process should not be applied until it is officially adopted. Therefore, the enter service criteria time should remain consistent with PRC24-002 until that time. 

NG Renewables also agrees that the Point of measurement or Point of Monitoring is the most appropriate place to locate the reference point of applicability (RPA). However, it would be helpful if MISO could clarify some of the elements in the IEEE 2800 diagram presented, specifically what a “supplemental IBR device” would mean in a MISO context.

Transmission Owner Feedback on Inverter-Based Resource Performance Requirements Proposed to IPWG

IPWG: Proposed IBR Performance Requirements (20230620)

July 14, 2023

In the June 20, 2023, meeting of the Interconnection Process Working Group (IPWG), stakeholders were invited to submit feedback on:

• Proposed changes to MISO’s draft Generator Interconnection Agreement (GIA) Tariff redline language
• Specific input on the following technical questions:
  • What is the preferred default setting for enter service intentional adjustable minimum delay and duration of enter service period? (Slide 9)
  • What changes, if any, should be made to the enter service criteria shown in the table of Slide 9?
  • What specific concerns, if any, could arise from MISO’s proposal to define the Reference Point of Applicability (RPA) as the Point of Interconnection (POI)?
  • MISO’s proposal to implement the Tariff changes for GIA’s resulting from DPP-2022-Cycle interconnection requests

Responses to MISO’s questions:

Proposed changes to MISO’s draft Generator Interconnection Agreement (GIA) Tariff redline language

• The Owners agree with the proposed tariff language, and agree that any applicable BPMs should be reviewed, as MISO has suggested.
• A header should be included for the table at the bottom of Section B, number 6, immediately before number 7.  As currently structured, the table appears to be tied to the final bullet of Section B, number 6.  As described in more detail below, a provision to allow for exceptions to section 7.2.2.6, included in the table, should be included in the tariff language that reflects the language in the Standard, which is provided below for reference.

Specific input on the following technical questions:

• What is the preferred default setting for enter service intentional adjustable minimum delay and duration of enter service period? (Slide 9)

• The Owners recommend intentional adjustable minimum time delay (T1) to be 0 s and duration of enter service period (T2) to be 300 s.  We believe that these values are reasonable without creating too much of a burden for IBR owners or TOs.
• A footnote should be added to the “Enter Service Criteria” that states the MISO default values may be modified within the IEEE 2800 range of allowable settings by Transmission Owner Local Planning Criteria (LPC).
• MISO should also consider including high level EMT modeling (PSCAD) which provides a more detailed representation of power system compared to standard phasor-based models (e.g. PSS/E models). PSCAD models are also useful for modeling generators in “weak” grid studies and sub-synchronous oscillation studies.
  • Inclusion of this requirement would support IC compliance with Owner interconnection standards that contain performance requirements, but these are limited control measures
  • The Owners recommend that the RPA remain the Point of Measurement (POM) on the high side of the plant GSU transformers to be consistent with NERC Standard PRC-024 and FERC Order 827. Requiring the Generator Owner to evaluate voltage and frequency ride-through at both the high side of the GSU transformers (POM) for PRC-024 compliance and the POI for IEEE 2800 compliance is burdensome without providing clear reliability benefits.

• What changes, if any, should be made to the enter service criteria shown in the table of Slide 9?

• What specific concerns, if any, could arise from MISO’s proposal to define the Reference Point of Applicability (RPA) as the Point of Interconnection (POI)?

MISO’s proposal to implement the Tariff changes for GIA’s resulting from DPP-2022-Cycle interconnection requests

• The Owners agree that these criteria should apply to DPP-2022-Cycle and beyond generator requests.

In conjunction with implementation of these IBR requirements, MISO should perform:

• a basic PSSE dynamic model review as part of the pre-kickoff application review that should include:
  • Ensure low/high voltage trip settings (VTGTPA models) are outside the ranges specified in Tables 11 and 12 of Section 7.2.2.1 of P2800.
  • Ensure sufficient active/reactive current injection during mandatory operation periods as described in Tables 11 and 12 of Section 7.2.2.1 (no momentary cessation) by reviewing the VDL1/VDL2 parameters of the REECA* model.
  • Ensure reactive current control priority is set (PQFLAG in REEC* model).
  • a review of the step response time for a distant fault that would reduce voltage at the POI to at least 50% as illustrated in the referenced example in Annex I of P2800. This analysis can be performed during DPP Phase 2/3 to ensure it meets the minimum requirement specified in Section 7.2.2.3.5 of P2800. This analysis would be similar to other model verification studies performed during the DPP (e.g. FERC Order 827 analysis).

MISO should indicate in Appendix G that TO-specific IBR requirements which are more stringent will supersede.

• While the TO can specify the nominal voltage for each voltage class, will a TO be able to specify different nominal voltages depending on the location and where will the nominal voltage be memorialized for each Interconnection Project for the transmission operators use? For example, a nominal voltage for a 500 kV system may be 510 kV in Louisiana and 520 kV in Arkansas.
• MISO should provide for exceptions to the response requirements for resources that are sited in weak grid locations through TO LPC.

IEEE2800 is to improve the reliability of IBR plants in weak grids so exceptions that may negatively impact reliability need to be considered carefully. MISO has included IEEE2800, section 7.2.2.6 “Restore output after voltage ride-through” (provided below for reference) provides for exceptions to the IBR performance requirements established in the standard and is included in the list of requirements for implementation with this proposed revision.

“Weak Grid” areas are areas of the system that do not have sufficient synchronous generation such that any change of real or reactive power can lead to large swings of angle and voltage.  Short circuit ratio is the primary consideration in identifying weak grid locations. 

IBRs that connect to Weak Grids may not be able to provide either fast frequency response or fast voltage control because doing so may lead to IBR control instability and cause protection mis-operations on transmission facilities.  For this reason, IEEE2800, section 7.2.2.6 “Restore output after voltage ride-through” allows for exceptions to some IBR requirements to achieve reliable transmission system operations and avoid the impacts that could result from the IBR performing according to the standard. 

In weak grid areas, IBR response requirements will need to be evaluated on a case-by-case basis.   Recommend that MISO work with Transmission Planners to establish a generic definition for Weak Grid but allow for TOs to provide their own definitions in their LPC, reflective of their own system’s conditions and the characteristics of the interconnecting resource(s).

• MISO should explicitly state in the tariff that exceptions to these requirements are permitted in weak grid areas, as defined by the Transmission Planner and agreed to by the impacted parties.

IEEE2800, section 7.2.2.6 “Restore output after voltage ride-through” 

The active power recovery time shall be configurable within a range between 1.0 s and 10 s. The default active power recovery time is 1 s; however, in weak grids, in order to reduce oscillatory behavior of the IBR plant upon fault recovery and maintain system stability, it may be desirable to reduce the average rate of active power recovery in consultation with the TS owner. Any modification of the recovery time from the default value shall be based on a mutual agreement between the IBR owner and the TS owner. The time to restore active power output shall be a target time with a tolerance that is the greater of ± 0.2 s or ± 10% of configured active power recovery time in seconds and shall not be interpreted as a maximum time.

July 14, 2023
Apex Clean Energy appreciates the opportunity to provide MISO feedback on the IPWG: Proposed IBR Performance Requirements.

NextEra Energy (NextEra) appreciates the opportunity to comment on MISO’s efforts to improve the grid reliability through implementing IEEE 2800 Inverter-Based Resource (IBR) Performance Requirements.   NextEra is aware of Original Equipment Manufacturer (OEM) comments submitted to other ISOs regarding the adaptation of the IEEE 2800 standards indicating the need for significant engineering effort to update the current products into compliance.  For that reason, we urge MISO to consider that the requirements be applicable to projects in DPP 2023 and beyond. 

Key comments/questions/recommendations from NextEra about MISO Interconnection Process Working Group's (IPWG) proposed IBR Performance Requirements:

• Applicability: NextEra agrees with MISO’s proposal that these requirements would not be enforced retrospectively and suggests that these be applicable to projects to be studied in DPP‑2023 onwards. The retrospective enforcement on legacy equipment poses challenges and add costs that in many cases cannot be recovered as the project is already locked in a Power Purchase Agreement (PPA). Retroactive application of standards sets a harmful precedent that undermines the business certainty necessary to develop and finance IBR projects and reduce the amount of generation capacity coming on the MISO system. Additionally, the potential design changes required to meet this requirement for the projects in DPP-2022 could trigger restudies and could cause potential project delays, on top of the already delayed interconnection study process.

• Enforcement: NextEra recommends the Transmission Owners and MISO coordinate to decide the applicability and timelines of these and other IEEE 2800-2022 requirements. Compliance should not be required for projects in-service, with equipment already on order or construction underway.

• Modifications/Repowers: Grandfathering should be allowed for projects with a modification or repower application in process to account for the already ordered/installed legacy equipment.

• Reference Point of Applicability (RPA): IEEE 2800-2022 Section 1, Figure 1 notes that moving the RPA from the point of measurement (POM) to the Point of Interconnection (POI) requires a consideration of the pros and cons. The example written into IEEE 2800 states, “The ability of IBR plants to meet the performance requirements in this standard may be impacted if the IBR owner is not allowed to install their measurement and control equipment at the POI substation.” It is recommended that MISO conduct a review of the feasibility and impact of moving the RPA to the POI.

• Queue Reform: MISO’s Generator Interconnection Queue Improvements process is currently ongoing. Has MISO considered what impact of its proposed IEEE 2800 adoption would have on the queue reform (if any)? Could the implementation of IEEE 2800-2022 before the queue reform is complete increase uncertainty around costs and timeline? NextEra would like to request that MISO coordinate the two efforts and consider the impacts to propose a clear timeline for implementation of the standard as well as clear guidance that minimizes impacts to IBR projects in the queue.

• OEM feedback: It is not known whether OEMs currently are able to comply with all aspects of IEEE 2800-2022 proposed for adoption. Requiring compliance with the proposed provisions within Appendix G may cause developers to either procure their inverters from a limited set of OEMs that can meet compliance with IEEE 2800 or potentially delay their schedules. It is recommended that MISO conduct a survey of IBR OEMs to assess their ability to comply with IEEE 2800 in the near term. If such a survey has been done, MISO is requested to share the survey results. NextEra proposes to apply the new requirements to GIAs resulting from the DPP-2023-Cycle thus giving OEMs more time to make the necessary software/hardware changes to be fully compatible with IEEE2800-2022 clauses.

• Upcoming verification guidelines: The ability of an OEM to meet IEEE 2800-2022 will likely be better understood following the publication of IEEE 2800.2. The current MISO DPP schedule expects GIAs stemming from DPP2022 cycle to be executed earlier, i.e., by July 2024. Self-certifying compliance without the verification/testing requirements is challenging for OEMs and developers. Testing and verification procedures are currently being developed under the IEEE 2800.2 standard, so the timing for implementation of IEEE 2800-2022 should be linked to the finalization of the IEEE 2800.2 standard. Additionally, clear guidance on the test and compliance demonstration is needed in the absence of P2800.2.

• Comment on the tariff language: Minor editing comment in the redline document to maintain consistency – please update the first sentence in “Section E. Transient Data Recording Equipment for Facilities above 20 MW” as follows – “Non-synchronous generating facilities IBR plants with generating capacities of more than 20 MW must monitor and record data for all frequency ride-through events, transient low-voltage disturbances that initiated reactive current injection, reactive current injection or momentary cessation for transient high-voltage disturbances, and inverter trips.”

Technical Feedback:

• Proposed changes to MISO’s draft Generator Interconnection Agreement (GIA) Tariff redline language (Attachment X redlines)

Based on industry feedback, a 10 mS requirement is recommended instead of 1 ms for data synchronization. 

• Specific input on the following technical questions:
• What is the preferred default setting for enter service intentional adjustable minimum delay and duration of enter service period? (Slide 9 PDF attachment)

NextEra recommends MISO reach out to OEMs for better feedback on these requirements including the time durations for enter service.

• What changes, if any, should make to the enter service criteria shown in the table of Slide 9?  Regarding the enter to service criteria, it is recommended to keep the buffer between the thresholds for fault ride through mode and return to service for a stable response. A recommendation for MISO’s consideration is enter Service limits between 0.95 < Vac < 1.05 and 59.5 Hz < F < 60.5 Hz