NOTICE DATE: April 6, 2026 

NOTICE TYPE: M-A040626-01 Operations 

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

INTENDED AUDIENCE: ERCOT Transmission Operators (TOs) 

DAYS AFFECTED: May 6, 2026, 11:00 a.m.; July 6, 2026. 

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

The survey must be completed for the test hour on May 6, 2026, at 11:00 a.m. Central Prevailing Time (CPT). Each ERCOT TO is required to plan to secure the measured load for the above test hour.

ACTION REQUIRED: The attached survey must be completed and emailed to Compliance@ercot.com no later than July 6, 2026. 

ADDITIONAL INFORMATION: ERCOT has prepared the attached survey form for use by ERCOT TOs to report data collected from the test hour of May 6, 2026, at 11:00 a.m. CPT. 

• 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. 

• Include the total load to shed for Under-Frequency Relay set points of 59.3, 59.1, 58.9, 58.7, and 58.5 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 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.  

• Each ERCOT TO must list the ERCOT-registered TDSPs included in its survey for which it is the designated ERCOT TO. List these TDSPs by Load area or using the comment section of the survey. 

• Complete both tabs on the survey form. The second tab includes additional relay information. 

• Use the attached "UFLS_Survey_Spreadsheet 2026 (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. 

If you are receiving email from a public ERCOT distribution list that you no longer wish to receive, please follow this link in order to unsubscribe from this list: http://lists.ercot.com. 

dg