EMT Modeling for CAISO Compliance: Expert Guide by Keentel Engineering

A Coordinated Electric System Interconnection Review—the utility’s deep-dive on technical and cost impacts of your project.

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Result: 90% reduction in false trips, saving over $250,000 in downtime

As the energy landscape continues to evolve with increasing integration of inverter-based resources (IBRs), battery energy storage systems (BESS), and advanced power electronics, California ISO (CAISO) mandates robust Electromagnetic Transient (EMT) modeling to ensure the reliability of the bulk electric power system. At Keentel Engineering, we specialize in developing, validating, and submitting EMT models that comply with CAISO’s stringent standards for both synchronous and inverter-based generators.

1. What is the primary reason CAISO requires EMT modeling?
To capture high-frequency transients and control dynamics not addressed in traditional RMS-based models, especially with increased inverter-based penetration.
2. What PSCAD files must be included in an EMT model submission?
File includes .pswx, .pscx, .pslx, along with associated .dll, .lib, and configuration files (.txt, etc.).
3. Is EMT modeling required for legacy Type 1 and 2 wind turbines?
No. These are currently exempt unless repowered or integrated with new IBR tech.
4. What’s the difference between “real-code” and standard models?
Real-code refers to firmware or compiled control logic directly used in models; standard models may require validation against field data.
5. How detailed must generator protections be in EMT models?
All AC and DC protections must be represented, including under/over voltage, frequency, loss-of-field, SSO mitigation, and more.
6. How should inverter inner controls be modeled?
Use a full IGBT switching model or average source with complete inner control detail; standard block models require performance validation.
7. What is the Multi-Mass Shaft Model requirement?
EMT models must reflect inertia constants, shaft spring constants, torque distribution, and damping—single-shaft approximations are disallowed.
8. What testing is required for model validation?
Flat run, three-phase fault test, step changes in voltage/reactive power and frequency/active power, and MOD-026/027 validation if applicable.
9. Can protection functions be disabled during simulations?
Yes. Temporarily disabling protections aids in diagnostic and comparative testing scenarios.
10. Are aggregate plant models acceptable for multi-resource sites?
Yes. An aggregated model may be submitted with each generating unit’s EMT model for holistic representation.
11. What are the usability requirements for EMT models?
Models must accept reference signals mid-simulation, support scaling, and dispatch below nameplate, and be capable of autonomous initialization.
12. What SCR value is used in test case configurations?
A typical SCR value of 3 is used for validation unless site-specific studies dictate otherwise.
13. Can models be submitted with manufacturer default settings?
No. All model parameters must reflect actual field-installed settings.
14. How fast must EMT models initialize?
Less than 5 seconds to full output with user-supplied terminal conditions is recommended.
15. What compiler and software versions are supported?
Models must be compiled with Intel Fortran v12+ and be compatible with PSCAD v4.6.3 or later.

In 1995, Sandip (Sonny) R. Patel earned his Electrical Engineering degree from the University of Illinois, specializing in Electrical Engineering . But degrees don’t build legacies—action does. For three decades, he’s been shaping the future of engineering, not just as a licensed Professional Engineer across multiple states (Florida, California, New York, West Virginia, and Minnesota), but as a doer. A builder. A leader. Not just an engineer. A Licensed Electrical Contractor in Florida with an Unlimited EC license. Not just an executive. The founder and CEO of KEENTEL LLC—where expertise meets execution. Three decades. Multiple states. Endless impact.