MOD-026-2 Transition

As inverter-based resources (IBRs), battery energy storage systems, renewable generation, and advanced transmission technologies continue to proliferate across the Bulk Power System (BPS), the importance of accurate systems modeling has never been greater. Recognizing this need, NERC has replaced Reliability Standards MOD-026-1 and MOD-027-1 with the new, consolidated MOD-026-2 Standard.

One of the most significant changes introduced by MOD-026-2 is the consolidation to separate model verification requirements into a single, comprehensive framework. Previously, MOD-026-1 focused on excitation systems and voltage/volt-ampere reactive controls, while MOD-027-1 addressed turbine-governor and active power of frequency control models.

The new Standard combines these requirements and expands applicability to transmission-connected dynamic reactive devices, high-voltage direct current (HVDC) systems, and IBR’s. By broadening the scope beyond traditional synchronous generation, MOD-026-2 provides a more complete representation of modern grid technologies.

Reliable planning and operational studies depend on the accuracy of the models used to evaluate system performance. MOD-026-2 strengthens verification and validation by requiring dynamic models to be compared against actual operation performance. This ensures that model parameters accurately reflect in-service equipment behavior and helps identify issues such as outdated settings, incorrect parameters, unmodeled control changes, or omitted protective functions. This will allow planners and operators to have greater confidence in studies used to assess system stability, voltage performance, frequency response, and resilience during disturbances.

Industry experience has demonstrated that inaccurate modeling of solar, wind, and battery storage facilities can lead to unexpected performance during system events. The new Standard directly addresses these challenges by supporting improved validation of IBR models and enhancing coordination among Planning Coordinators, Transmission Planners, Generator Owners, and Transmission Owners. Better data sharing and model consistency help ensure that all entities are working from the same validated information.

MOD-026-2 represents more than a routine Standards update; it is a significant advancement in NERC’s approach to model validation and reliability assessment. By expanding model verification to include modern grid technologies, requiring validation against actual equipment performance, and creating a unified framework for data coordination, the Standard strengthens the foundation of reliability planning across the BPS. As implementation continues following its April 1, 2026, effective date, MOD-026-2 will help the industry improve study accuracy, enhance grid resilience, and maintain the high level of reliability expected throughout North America.