The proposed reliability standard to require ride-through protection for inverter-based resources (IBR) cleared a major hurdle last week by passing a formal ballot round after multiple previous attempts to get it over the finish line ended unsuccessfully.  

Now the way is clear for NERC’s Board of Trustees to vote on it and four other standards whose passage is required to meet FERC’s deadline of Nov. 4 to submit the first of three tranches of IBR-focused standards. Those votes are set to take place at a special board meeting scheduled for Oct. 8.  

The formal ballot for PRC-029-1 (Frequency and voltage ride-through requirements for IBRs) concluded Oct. 4 with 158 votes cast in favor of passage and 50 votes against (with comment); 59 ballot pool members either abstained or did not vote. After applying NERC’s segment weighting, which lowers the impact from segments with fewer voters, the final result is a 77.88% weighted segment value supporting passage, comfortably above the two-thirds majority needed for passage.  

Failing to meet the two-thirds threshold would not necessarily have prevented PRC-029-1 from passage. Under Section 321 of the ERO’s Rules of Procedure — invoked for the first time by NERC’s board at its August meeting — the standard could have been considered approved with a 60% segment-weighted majority. (See “Board Invokes Standards Authority to Meet IBR Deadline,” NERC Board of Trustees/MRC Briefs: Aug. 15, 2024.) 

In that case, the board would have had to solicit written public comment on the proposed standard. If satisfied the standard was just, reasonable, not unduly discriminatory or preferential, and in the public interest, it then could file it with FERC. 

The Section 321 authority also required NERC’s Standards Committee to conduct a technical conference to solicit input from industry stakeholders. At the technical conference, held Sept. 4-5 in Washington, D.C., representatives from a range of industry segments — including original equipment manufacturers and utilities — discussed their objections to the proposed standard. (See NERC, Industry Discuss IBR Issues in Technical Conference.) 

Following the conference, NERC revised the standard to address attendees’ concerns, including the clarity of the definition of “ride-through,” criteria for frequency ride-through performance and exemptions to ride-through criteria for equipment with hardware limits. Most stakeholders commenting on the revised draft felt the changes reflected opinions expressed at the conference, though many also felt more could have been done to accommodate concerns.  

In a long comment, Jens Boemer of the Electric Power Research Institute said the new draft standard “appears to be improved” and expressed appreciation for the standard drafting team for taking the comments of EPRI and others on board. However, he also indicated “further improvements” would be welcome, including: 

• • further clarification of the definitions of IBRs and the term “ride-through,” and specific grid conditions for which the ride-through requirements apply. 

• • guidance for determining the maximum capability of an IBR. 

• • exemptions for legacy equipment that may be challenging to update because of lack of manufacturer support. 

At its meeting Oct. 8, NERC’s board will vote on submitting PRC-029-1 to FERC for approval, along with the other IBR standards approved in previous ballot rounds: 

• • PRC-024-4 — Frequency and voltage protection settings for synchronous generators, Type 1 and Type 2 wind resources, and synchronous condensers. 

• • PRC-028-1 — Disturbance monitoring and reporting requirements for inverter-based resources. 

• • PRC-002-5 — Disturbance monitoring and reporting requirements. 

• • PRC-030-1 — Unexpected inverter-based resource event mitigation. 

The board also will consider accepting revisions to the charter of NERC’s Reliability and Security Technical Committee (RSTC) that are intended to improve the balance of industry representation at meetings. The new rules will allow a sector to seek a special election to fill an open seat representing it, rather than have that seat convert to an at-large member as the current charter provides. 

In addition, they will remove the numerical cap on the number of representatives from a sector that can serve as at-large members and will direct the RSTC Nominating Subcommittee to prioritize balanced sector representation.