NERC is requesting comments from industry through Sept. 10 on four proposed reliability standards aimed at satisfying FERC’s directive on inverter-based resources.
The ERO posted the standards in its Standards Balloting System on Aug. 8, along with the latest update to the ERO’s Reliability Standards Development Plan (RSDP), which lays out the planned schedule of standards development from 2026 to 2028. Comments on the RSDP are due by Sept. 5.
The following standards are up for comment:
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- MOD-032-2 — Data for power system modeling and analysis;
- IRO-010-6 — Reliability coordinator data and information specification and collection;
- TOP-003-8 — Transmission operator and balancing authority data and information specification and collection; and
- MOD-033-3 — Steady-state and dynamic system model validation.
All of the standards were developed under Project 2022-02 (Uniform modeling framework for IBRs) except for MOD-033-3, which originated from Project 2021-01 (System model validation with IBRs). NERC’s Standards Committee approved all of them for posting at its April 16 meeting. (See NERC Standards Committee Approves IBR Posting.)
In Order 901, issued in October 2023, FERC directed NERC to develop requirements pertaining to the reliable connection and operation of IBRs, grouped into four milestones to be submitted over the following three years (RM22-12). (See FERC Orders Reliability Rules for Inverter-Based Resources.) Included in Milestone 3, due Nov. 4, are requirements for providing data on IBRs and distributed energy resources to entities responsible for planning and operating the grid.
To satisfy this mandate, the standard development team for Project 2022-02 decided to update MOD-032-2 to include language from the ERO Unacceptable Models List, renamed Aug. 1 from the ERO Acceptable Models List Criteria Document. A new requirement allows planning coordinators and transmission planners to specify whether they will accept standard-library dynamic models, user-written models or both.
NERC said the requirement is “responsive to FERC concerns about model usability and non-convergence by requiring PCs and TPs … to specify usability requirements and require appropriate model documentation and instructions,” while also allowing a level of flexibility requested by stakeholders in industry engagement workshops.
Another requirement was rewritten “to require estimation of modeling data if the responsible entity … is unable to gather required data.” This is intended to give entities a way to meet FERC’s directive of submitting data even if the actual information is unavailable; however, entities that submit estimates must explain the “limitations of the estimated data” — such as legal prohibitions on requesting certain data, incomplete records of connected facilities and lack of mechanism to enforce collection — “and the method used for estimation.”
The final revisions recorded by the SDT apply to TOP-003-8 and IRO-010-6, and state that “entities responsible for developing and distributing data specifications shall include requirements for model submissions consistent with the model submitted for planning purposes, as applicable.”
The drafting team for Project 2021-01 said that “no substantive changes are needed” for MOD-033, but members did note “opportunities to improve the clarity of both the [standard’s] requirements and measures.” To this end, they proposed to add the glossary term “model validation” — approved in May by industry ballot for inclusion in NERC’s Glossary of Terms — to the standard, along with a requirement that the PC implement a model validation process for its “portion of the existing system.”
Team members also updated additional language in the standard to correspond with the “model validation” definition and to reduce redundancy and wordiness.
