On December 19, 2024, FERC issued a Notice of Proposed Rulemaking (NOPR) approving the addition of a new definition of the term “ride” to the North American Electric Reliability Corporation (NERC) glossary and approving proposed protection and control (PRC) standards PRC-024-4 (Frequency and Voltage Protection Settings for Synchronous Generators, Type 1 and Type 2 Wind Resources, and Synchronous Condensers) and PRC-029-1 (Inverter Bridge Resources (IBR) Frequency and Voltage Withstandability Requirements). According to FERC, these reliability standards are intended to address reliability deficiencies associated with IBR tripping or momentary outages. The new rules ensure that IBRs can “ride through” frequency and voltage excursions, such as faults in the transmission system or transmission subsystem. In the NOPR, FERC seeks comments on the proposed rules and informational document requirements that will assist FERC in analyzing the impact of the proposed exceptions to certain IBR rules.
NERC submitted two PRC standards and a “pass-through” determination to FERC on November 4, 2024, in response to the Commission’s Order 901, Consideration of Reliability Standards for Inverter Resources, Order 901, 185 FERC § 61.042 (2023). In Order 901, FERC found that some IBRs “are not configured or programmed to support grid voltage and frequency during system upsets and, as a result, reduce output power, experience momentary outages, or shut down due to changes in system voltage or frequency.” FERC argued that these problems are exacerbated when IBRs operate collectively. The standards established by FERC in Order 901 are intended to require registered IBRs to overcome certain system disturbances and protect IBR equipment, similar to the mechanisms used to synchronize the use of generating resources. Specific proposed reliability standards include the following:
PRC-024-4 is intended to “ensure that protection of synchronous generators, Type 1 and Type 2 wind resources, and synchronous condensers does not result in tripping during specified frequency and voltage excursions supporting the power system.” The proposed revisions retain the voltage and frequency setting requirements for synchronous generators, synchronous condensers, and Type 1 and Type 2 wind resources, and remove the performance requirements for IBR functionality that were already included in proposed PRC-029. According to NERC’s proposed definition of IBR in the Glossary (proposed in a separate document pending review in Docket No. RD25-1), Type 1 and Type 2 wind resources are not considered IBRs because they operate as asynchronous resources.
PRC-029-1 is intended to “ensure that IBRs can cope with disturbances to support power systems during and after specified frequency and voltage excursions. NERC’s definition of IBRs includes solar photovoltaic systems, Type 3 and Type 4 wind systems, battery storage systems, and fuel cell equipment.” Under proposed PRC-029, IBRs must meet or exceed the crossing requirements specified in the “areas to be crossed” specified in Institute of Electrical and Electronics Engineers (IEEE) 2800-2022, except for the following four conditions: (i) An interrupt is required to open to reset a faulty IBR, (ii) The voltage at the high-end of the transformer exceeds the allowable hardware limits, (iii) The instantaneous change in phase angle of the positive sequence voltage at the high-end of the main power transformer exceeds 25 kWh and is caused by a failure to transfer event on the transmission system, or (iv) The voltage at the high-end of the transformer exceeds 1.1 per unit for more than 45 seconds or exceeds 1.18 per unit for more than 2 seconds.
PRC-029 allows existing IBRs that were in service prior to the effective date of the standard to seek an exemption from the voltage and withstand requirements if equipment replacement is required to comply. Entities may apply for an exemption within twelve months of the effective date of PRC-029-1.
In PRC-029-1, the word “through” means that “the installation/facility remains connected and continues to operate despite voltage or frequency disturbances in the system.”
In addition to the reliability standards and definitions, NOPR proposes to require NERC to submit two informational documents detailing requests for waivers from frequency and/or voltage conservation requirements by owners of legacy IBR generators to better understand the actual impact of the proposed waivers. FERC seeks comment on all aspects of the proposed approval.
Entities must submit comments within 60 days of publication of the NOPR in the Federal Register. Responses must be submitted within 90 days of publication of the NOPR in the Federal Register. FERC’s order is available here, “Frequency and Voltage Protection Settings and Reliability Standards for Inverter Resources,” 189 FERC ¶ 61.212 (2024) (NOPR).
Disclaimer: Due to the general nature of this update, the information provided here may not apply to all situations and should not be acted upon without obtaining specific legal advice based on individual circumstances. Attorney Advertising.
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Post time: Jan-08-2025