NOTICE DATE: February 21, 2025

NOTICE TYPE: M-A022125-01 Operations

SHORT DESCRIPTION: Request for Information Needed to Prepare Geomagnetic Disturbance (GMD) Vulnerability Assessments

INTENDED AUDIENCE: Transmission Service Providers (TSPs), Resource Entities with Point of Interconnection (POI) voltage levels above 60-kV, and NERC-registered Transmission Planners, Transmission Owners, and Generator Owners

DAYS AFFECTED: May 31, 2025

LONG DESCRIPTION: In order to facilitate preparation of the GMD Vulnerability Assessments and pursuant to paragraph (2) of Planning Guide Section 6.11, Process for Developing Geomagnetically-Induced Current (GIC) System Models, ERCOT requests that TSPs and Resource Entities with POI voltage levels above 60-kV provide a list of equipment potentially removed from service as a result of protection system operation or misoperation due to harmonics that could result from the benchmark and supplemental GMD events as described in “Table 1: Steady State Planning GMD Event” of NERC Reliability Standard TPL-007-4, Transmission System Planned Performance for Geomagnetic Disturbance Events.

ACTION REQUIRED: TSPs and Resource Entities with POI voltage levels above 60-kV are required to assess the impact of the benchmark and supplemental GMD events on their Reactive Power compensation devices and other Transmission Facilities to develop and provide to ERCOT a list of equipment potentially removed from service as a result of protection system operation or misoperation due to harmonics that could result from the benchmark and supplemental GMD events. Complete the attached “ERCOT GMD Events Data Request” form and email it to GMDVA@ercot.com with “GMD Events Data Request” in the subject line by May 31, 2025. 

Any entity from which no response is received by May 31, 2025, will be presumed to have no equipment potentially removed from service as a result of protection system operation or misoperation due to harmonics that could result from the benchmark or supplemental GMD events.

ADDITIONAL INFORMATION: In addition to TSPs and Resource Entities, this Notice is also issued to compliance contacts for all NERC-registered Transmission Planners, Generator Owners, and Transmission Owners in the ERCOT Region.

On November 6, 2024, ERCOT posted the final Geomagnetically Induced Current (GIC) flow results for the benchmark and supplemental GMD events as described in Market Notice M-A110724-01 FINAL Geomagnetically Induced Current (GIC) flow results posted.

The NERC Geomagnetic Disturbance Planning Guide, located on the NERC website, and the Reliability and Operations Subcommittee-approved document titled, “Methodology for Assessing GMD Impacts on ERCOT Power Systems,” located on the Steady State Working Group landing page, can be used as references to help identify equipment potentially removed from service as a result of protection system operation or misoperation due to harmonics that could result from the benchmark and supplemental GMD events.

CONTACT: Please send any questions via email to GMDVA@ercot.com.

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