NOTICE DATE: April 8, 2025

NOTICE TYPE: M-A040825-01 Operations 

SHORT DESCRIPTION: Annual Under-Frequency Load Shedding (UFLS) survey of Transmission Operators (TOs)

INTENDED AUDIENCE: ERCOT Transmission Operators (TOs)

DAYS AFFECTED: May 8, 2025; July 8, 2025.

LONG DESCRIPTION: In accordance with Nodal Operating Guides Section 2.6.1, Automatic Firm Load Shedding, ERCOT requests that all TOs in the ERCOT Region complete the attached Under-Frequency Load Shedding (UFLS) survey.  

The survey must be completed for a test hour on May 8, 2025, at 11:00 a.m. Central Prevailing Time (CPT). Each TO is required to plan to secure the measured load for the above test hour.

ACTION REQUIRED: The attached survey must be completed and submitted no later than July 8, 2025 via e-mail to Compliance@ercot.com.

ADDITIONAL INFORMATION: To complete the survey:

• If the data cannot be collected for the selected test hour for any reason, including equipment failure, please submit the information for an hour that is as close to the selected test hour as possible and include an explanation.
  
  

• Please include the total load to shed for Under- Frequency Relay set points of 59.3, 59.1, 58.9, 58.7, and 58.5 hertz (Hz) corresponding to load relief of at least 5%, 15%, and 25%.
  
  

• If utilized, please include the optional load relief requirements for the Supplemental Anti-Stall UFLS Stages to shed at each of the three thresholds of 90, 120, and 150 seconds at 59.5 Hz of at least 1.5%, 3.0%, and 4.5% of the TO load, respectively.
  
  

• TOs must list the ERCOT-registered TDSPs included in their survey for which they are the designated TO. Please list these TDSPs by Load area using the comment section of the survey in Column AB.
  
  

• Please complete both tabs on the survey form. The second tab requests additional relay information.
  
  

• Please use the attached “UFLS_Survey_Spreadsheet 2025 (TO Copy).xlsx” and the same naming convention for any other supporting documentation submitted with the survey.
  

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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