Developed in response to Order No. 901, FERC’s recent approval of the second tranche of NERC Reliability Standards marks a pivotal shift in how the industry models, validates, and governs data for inverter-based resources (IBRs) connected to the Bulk Power System.
These standards formalize expectations that many organizations have treated as emerging best practice—especially around high-fidelity, event-aligned modeling—and elevate them to an enforceable reliability framework.
What Was Approved
The approved package includes foundational updates across planning and operations, with a strong emphasis on model integrity and data traceability:
- MOD-026-2 – Verification and Validation of Dynamic Models and Data: Strengthens requirements to ensure dynamic models accurately reflect installed equipment and performance
- MOD-033-3 – System Model Validation: Expands expectations for validating system models using real-world performance and post-event analysis
- MOD-032-2 – Data for Power System Modeling and Analysis: Significantly expands data requirements and documentation for modeling IBR behavior and characteristics
- IRO-010-6 and TOP-003-8 – Enhanced operational data specifications: Improves the consistency, completeness, and usability of operational model data exchanged across entities
- New glossary definitions for DER, Model Verification, and Model Validation: Clarifies key terms and reduces ambiguity in implementation and audit interpretation
Why This Matters: A Structural Shift in Grid Modeling
IBRs are control-driven technologies with dynamic behaviors that may not be captured sufficiently by traditional planning approaches alone. As penetration levels increase, the accuracy of IBR models becomes a primary determinant of planning study quality, operating strategy effectiveness, and event analysis credibility.
With this tranche, the industry direction becomes unmistakable:
1) EMT Modeling Expectations Are Now Formalized
Electromagnetic transient (EMT) modeling—long recognized as essential for analyzing fast controls and protection interactions—is now formalized for registered IBRs, with limited legacy exemptions. This change increases expectations for model availability, tool capability, and engineering workflow maturity.
2) Verification and Post-Event Validation Become Institutionalized
The standards reinforce two critical disciplines:
- Model verification (confirming the model matches the installed configuration)
- Model validation (confirming the model reproduces observed behavior during real disturbances)
That combination drives continuous model improvement—not just “model delivery at interconnection,” but model maintenance over the resource lifecycle.
3) IBR and Aggregated DER Data Requirements Expand
IBR modeling quality depends on detailed, timely, and well-governed data. The expanded requirements increase the focus on traceable parameters, documentation, and consistent data exchange among Generator Owners, Transmission Planners, Planning Coordinators, and operating entities.
4) Planning and Operations Modeling Frameworks Are More Tightly Aligned
By strengthening both planning standards (MOD) and operating data specifications (IRO/TOP), the approved package reduces gaps between how the system is planned and how it is operated—especially important as IBR behavior can be highly sensitive to disturbance conditions.
Timeline: The Work Starts Now
While full implementation is required before January 1, 2030, organizations with significant IBR portfolios should begin readiness efforts now. The modeling and validation workload—especially for EMT studies, data governance, and cross-entity coordination—can take years to scale effectively.
Readiness Priorities for Registered Entities
Organizations preparing for these requirements should focus on four practical areas:
- Model readiness: positive-sequence and EMT model availability, completeness, and version control
- Verification processes: repeatable workflows, responsibilities, evidence retention, and change management
- Data governance: parameter traceability, documentation standards, secure data exchange processes
- Resourcing and capacity planning: staffing, tool capability, and increased model review and coordination workload
The Bottom Line
FERC’s approval signals a new phase of reliability expectations: high-fidelity IBR modeling, verification, and validation are no longer optional. As the Bulk Power System becomes increasingly inverter-dominated, the industry’s modeling discipline must evolve from periodic study support to continuous lifecycle assurance.
Organizations that act early—building model governance, scaling verification and validation workflows, and aligning planning and operational data practices—will be best positioned for these changes. To find out how we can help you meet the standards efficiently and strengthen reliability in the process, reach out to our team of experts today using the form below.
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