PRC-029-2 Turns Compliance into a Closed-Loop Discipline: Unify Design, Models, and Events

FERC approved PRC-029-1 in July 2025, and its successor, PRC-029-2, took effect October 1, 2026. PRC-029-2 keeps the R1 to R3 ride-through requirements and their compliance dates, apart from new Attachment 1 relief for certain HVDC-connected IBRs, and rewrites the R4 hardware-limitation exemption. It sets ride-through performance requirements for inverter-based resources (IBRs) and expects evidence that plants perform in the field, not only that settings are right on paper. That evidence depends on disturbance data and on models that match the plant, so protection settings, dynamic models and event records need to be managed together.

Why PRC-029-2 Is Different: Three Proofs, One Outcome

PRC-029-2 introduces performance-based ride-through obligations for IBRs, and its implementation plan ties the operational requirements to PRC-028-1 disturbance monitoring, while PRC-030-1 covers analysis of unexpected events. That means your evidence chain must connect:

1. how the plant is configured,
2. how the model behaves, and
3. how the units actually performed during grid events.

Key details to internalize:

• No momentary cessation in the continuous or mandatory operation regions: IBRs must keep exchanging current to support voltage, and may block current only in the permissive region below 0.10 per unit. A non-fault phase jump of more than 25 electrical degrees is an R1 exception: the plant is not required to ride through it.
• Evidence retention is required; PRC-029-2 specifies minimum retention periods for R1-R4 materials.

Applicability covers BES IBRs and Category 2 IBRs, which are non-BES IBRs that have or contribute to 20 MVA or more delivered to a common point of connection at 60 kV or above. Plan for both populations. 

The Closed-Loop Workflow PRC-029-2 Demands

1) Design Intent: Protection & Control Review Across Relays, PPCs, and Inverters

GridStrong centralizes "as-left" settings and automates PRC-029-2 compliance checks across inverter controls, feeder relays, and the plant controller. The PRC-029-2 module packages the required procedure, design evaluation, settings analysis, and ongoing evidence capture, so reviews are kept in one place. 

Why this matters: PRC-029-2 is about performance zones, not just setpoint lists. Automated checks catch transcription mistakes and protection logic that would trip inside the must Ride-through zone. 

2) Model Fidelity: PSS®E/PSCAD Studies That Match As-Left Settings

Compliance hinges on models that reflect reality. GridStrong aligns plant models to field settings, runs required ride-through cases, and overlays simulated vs. measured responses in tools like PSS®E, PSCAD, and TSAT - closing the loop between design and study. 

Practical advantages:

• Connect once and keep models in step with the plant. Live data keeps model assumptions current, and validation runs against recorded events are set up once and repeated as needed.
• Consistent reporting. Standard exports for internal reviews and audits.

For ERCOT sites, GridStrong's MQT workflow plans, executes, benchmarks, and reports all required legacy and preferred cases - with side-by-side overlays and pre-/post-mod comparisons. 

3) Operational Proof: Event Monitoring, Detection, and Reporting

PRC-029-2 expects the plant to ride through events that PRC-028-1 equipment records, and PRC-030-1 requires the owner to analyze qualifying output losses and then either correct the cause or justify why not. GridStrong ingests SCADA, DFR, SER, and PMU data; auto-identifies ride-through failures; and generates the required evidence packages and corrective action tracking.

Design parameters, model parameters and event performance are kept in one system so they can be compared directly.

Timelines and Scope: What to Expect

• Regulatory status. FERC approved PRC-029-1 on July 24, 2025 (Docket No. RM25-3-000) and PRC-029-2 on September 30, 2026 (Docket No. RD26-10-000).
• Effective date. PRC-029-2 took effect October 1, 2026. PRC-029-1 never took effect; PRC-029-2 replaced it on October 1, 2026, and deadlines still count from that date. BES IBRs meet the R1-R3 design requirements from that date and registered Category 2 IBRs from January 1, 2027; R4 applies to both from October 1, 2026. The operational parts of R1-R3 apply once PRC-028-1 disturbance monitoring is in place, and R4 hardware-limitation documentation is due to the listed entities no later than 12 months after October 1, 2026, that is October 1, 2027, for an IBR that was in service, with a Generator Owner responsible for compliance with Reliability Standards for it, by October 1, 2026.
• Registration thresholds. Category 2 IBRs (non-BES IBRs that have or contribute to 20 MVA or more at a common point of 60 kV or above) are now registered, and BES IBRs (under BES inclusion I4, more than 75 MVA gross nameplate aggregated to a common point of connection at 100 kV or above) remain covered.

Implication: BES design evaluations are due now, Category 2 design compliance starts January 1, 2027, and operational proof depends on PRC-028-1 recording, which phases in through January 1, 2030.

What "Unified" Looks Like in Practice

GridStrong covers PRC-028-1, PRC-029-2 and PRC-030-1 compliance, modeling and event analysis in one platform.

• PRC-029-2 Module: Compliance procedure, design evaluation, ongoing settings analysis, model management, and event reporting.
• Modeling Modules (MOD-026-2 and MOD-032): Study automation, model validation, and benchmarking across PSS(R)E, PSCAD, and TSAT.
• Event Identification & Analysis (PRC-028-1 / PRC-030-1): Equipment inventory, event data management, automated analysis, and corrective action reporting.

A Practical PRC-029-2 Readiness Plan

1. Map the fleet. Identify BES and Category 2 IBRs and confirm PRC-028-1 recording coverage per collector bus and feeder priorities.
2. Baseline "as-left." Centralize inverter, relay, and PPC settings; flag settings that would trip inside the PRC-029-2 must Ride-through zone; eliminate momentary-cessation risks.
3. Align models. Synchronize PSS®E/PSCAD parameters with settings; run required ride-through scenarios; benchmark and retain overlays.
4. Automate event analytics. Ingest SCADA, DFR, SER and PMU data; flag ride-through failures and any complete loss of output or change of at least 20 MW and 10 percent of gross nameplate within 4 seconds; draft PRC-030-1 analyses and corrective action plans.
5. Harden evidence. Use an evidence locker, standardized workflows, and standard exports to meet retention and audit expectations.  

The Upshot

PRC-029-2 touches protection engineering, dynamic modeling and operational event analysis, so its evidence has to be consistent across all three. GridStrong keeps settings, models and event records together so that evidence comes from one place.