Strengthening Grid Reliability: New Dynamic Modeling Requirements for Large Loads in Texas

As large scale data centers, cryptocurrency mining facilities, and other power-intensive operations continue to grow, maintaining grid stability has become a critical priority. In response, ERCOT has introduced Planning Guide Revision Request (PGRR) 144, establishing enhanced requirements for dynamic modeling and stability analysis of large loads.

This update is designed to ensure that large electrical facilities are accurately represented in system studies, helping prevent voltage collapse, frequency instability, and large-scale outages.

Understanding PGRR 144

PGRR 144 focuses on improving how large loads—especially Large Electronic Loads (LELs)are modeled in ERCOT’s planning and operational tools.

These models must now:



• Accurately represent real-world equipment behavior
• Be compatible with PSS/E, PSCAD, and TSAT platforms
• Demonstrate voltage and frequency ride-through capability
• Include hardware validation for converter-based systems

With more than 200 GW of large loads seeking interconnection, ERCOT has identified dynamic modeling as essential for grid reliability.

Why Dynamic Modeling Matters

Dynamic models simulate how electrical systems respond to disturbances such as:

• Transmission faults
• Voltage sags
• Frequency excursions
• Sudden load changes

Poor quality models can underestimate risks, leading to cascading failures. Since 2022, ERCOT has observed repeated incidents where large loads tripped during minor disturbances, highlighting the need for better modeling standards.

New Requirements for Large Load Developers

1. Comprehensive Dynamic Data

Facility owners must submit detailed models covering:

• Cooling systems
• Power electronics
• Control systems
• Protection relays
• Computer-based loads

These models must reflect actual field settings and operating conditions.

2. Mandatory Model Quality Testing

Each submitted model must pass standardized tests, including:

• Flat start (no-disturbance) test
• Large voltage disturbance test
• Frequency disturbance test
• System strength test (for inverter-based systems)

These tests verify that models initialize correctly and remain stable under stress.

3. Converter and Inverter Validation

For Large Electronic Loads, ERCOT now requires:

• PSCAD hardware benchmarking
• Voltage ride-through verification
• Subsynchronous oscillation testing

This ensures that power electronic devices behave in simulations the same way they do in the field.

4. Review Checkpoints Throughout Development

Model reviews are required at three major stages:

1. Before dynamic stability studies
2. Before Quarterly Stability Assessment (QSA)
3. Before initial energization (LELs only)

These checkpoints help identify issues early and reduce costly redesigns.

Impact on Project Schedules and Costs

While ERCOT estimates no direct capital cost impact, it anticipates:

• $200K–$250K annual staffing costs
• Additional review time
• Increased documentation effor

One full-time engineering position will be added to support these activities.

Regulatory Oversight

PGRR 144 becomes effective after approval by the Public Utility Commission of Texas (PUCT). Once approved, all new and modified large loads must comply.

How Keentel Engineering Supports Compliance

Keentel Engineering assists large load developers by providing:

Dynamic model development (PSS/E, PSCAD, TSAT)
Model quality and validation testing
LLIS documentation support
ERCOT submission management
Stability study coordination
As-built model certification

Our team ensures that projects meet regulatory requirements while minimizing delays.

Frequently Asked Questions (FAQs)