This summary explains the Potential Planning Guide Revision Request (PGRR) presented at the February 19th, 2026, Large Load Working Group (LLWG) meeting. It outlines the new requirements for Large Loads (LLs) and Large Electronic Loads (LELs) to ensure the Texas power grid remains reliable as these facilities grow.
Large Load Interconnection Background
ERCOT is proposing these changes because there are currently over 200 GW of Large Load interconnection requests in the queue. Since 2022, several LEL tripping events have occurred during grid disturbances, posing a potential reliability risk to the ERCOT system. The PGRR aims to clarify the requirements for dynamics data and the milestones for reviewing these models.
Purpose: Dynamic Data Requirements and Model Quality Tests
The primary purpose of this PGRR is to clarify dynamic data requirements and mandate Model Quality Tests (MQT). It establishes clear milestones for data submission during the interconnection process and defines the formal review process for material changes made to existing LELs.
Dynamic Data Requirements
Submission Standards: Owners must provide models, parameters, and supporting documentation that accurately represent the behavior of LL equipment like cooling systems, computer-based loads, and control systems.
Software Compatibility: Data must be compatible with ERCOT’s planning and operations tools.
- PSS/E: Required for all Large Loads for large-scale interconnection studies.
- PSCAD: While previously limited to specific studies, PSCAD is now required for all Large Loads to allow for detailed “Electromagnetic Transient” studies, which are crucial for analyzing weak areas of the grid.
- TSAT: Required for all LLs if a “User Defined Model” (UDM) is submitted for PSS/E to support real-time analysis.
Model Quality Testing (MQT) Framework
The PGRR establishes a framework to verify that the dynamic models provided by facility owners actually work correctly:
- Site-Specific MQT (All LLs): Includes a Flat Start Test (verifying the model is stable when there is no disturbance) and a Large Voltage Disturbance (VRT) Test (modeling how the facility handles voltage “ride-through” at the point of connection).
- Converter Model Validation (LELs Only): This is a hardware-type test to ensure the PSCAD model accurately reflects the behavior of the specific power electronics (like UPS converters) used in the facility.
- Performance Goals: For LELs, MQTs must prove the project meets specific ride-through criteria (such as those in ongoing NOGRR282). For non-LEL facilities, the purpose is to improve ERCOT’s general understanding of their voltage ride-through capabilities.
Dynamic Data Submission Milestones
The interconnection process includes three mandatory review points for data submission:
- Stability Study (LLIS): Before the lead Transmission Service Provider initiates the stability study for any LL, they must receive and review the MQT and VRT performance data.
- Quarterly Stability Assessment (QSA): Prior to entering the QSA, all LLs must have their model performance tested. ERCOT checks for consistency against the data used in the initial stability study and ensures performance is consistent across different software platforms (e.g., matching PSS/E results against PSCAD).
- Initial Energization (LEL Only): Before energization, an LEL must submit “as-built” data. This is reviewed for consistency against the “as-studied” (QSA) data, and the owner must provide an attestation confirming the as-built data aligns with the actual field settings.
Material Changes to Existing LELs
Existing Large Electronic Loads through the LLIS process again if they undergo a material change. This is defined as any modification that “materially changes dynamic characteristics or operating behavior in a manner that may affect system performance or ride-through capability”. Examples of Material Changes:
- Changes in technology (e.g., converting a cryptocurrency mining load into a data center) or
- Changes in controls (e.g., protection schemes or relay settings) that affect how the facility responds to voltage or frequency events at the POI.
Next Steps
ERCOT intends to formally submit this PGRR for review by the Reliability and Operations Subcommittee (ROS) in March 2026, allowing stakeholders to provide comments.
