NOTICE DATE: December 19, 2025

NOTICE TYPE: M-C121925-01 NPRR

SHORT DESCRIPTION: Implementation Details of NPRR1283, Modification of SSR Mitigation Timeline

INTENDED AUDIENCE: All Market Participants

DAYS AFFECTED: January 1, 2026

LONG DESCRIPTION: On January 1, 2026, Protocol language associated with Nodal Protocol Revision Request (NPRR) 1283, Modification of SSR Mitigation Timeline, will be implemented. 

NPRR1283 changes the current requirement that any required Subsynchronous Resonance (SSR) studies be complete and mitigation be in place prior to Initial Synchronization of a new Generation Resource, Energy Storage Resource (ESR), or Settlement Only Generator (SOG). Based on recognition that Subsynchronous Ferroresonance (SSFR) can be a risk upon energization, this NPRR requires that these steps now be completed prior to Initial Energization to ensure that SSFR risk has been evaluated and mitigated.

ADDITIONAL INFORMATION: Pursuant to Protocol Section 21.6, Nodal Protocol Revision Implementation, ERCOT is required to provide notice as soon as practicable, but no later than ten days prior to implementation.  

NPRR1283 and the associated documents can be found on the ERCOT website.

CONTACT: If you have any questions, please contact your ERCOT Account Manager. You may also call the general ERCOT Client Services phone number at (512) 248-3900 or contact ERCOT Client Services via email at ClientServices@ercot.com.

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