The grid doesn't stop during a disturbance. Your inverters shouldn't either.
As solar, wind, and battery storage make up an ever-larger share of the Bulk Power System, one question becomes increasingly critical: when the grid gets stressed — a voltage dip, a frequency swing, a fault — will your inverter-based resources stay online and keep supporting the system? Or will they disconnect at exactly the moment reliability needs them most?
That's the question NERC PRC-029-1 was written to answer. Driven by FERC Order No. 901 and years of post-disturbance event analysis showing IBRs tripping or curtailing during grid events, PRC-029-1 establishes mandatory frequency and voltage ride-through performance requirements for Inverter-Based Resources — and it's one of the most operationally complex standards the IBR space has seen.
With an effective date of October 1, 2026, the compliance window is open now. Design requirements come first, and operational requirements follow as disturbance monitoring equipment comes online under PRC-028-1.
What PRC-029-1 Actually Requires
PRC-029-1 applies to Generator Owners of BES IBRs and non-BES IBRs with an aggregate nameplate capacity of 20 MVA or more connected at voltages of 60 kV or higher. The standard centers on three performance requirements and one exemption pathway:
R1 — Voltage Ride-Through: IBRs must remain connected and continue exchanging current during voltage disturbances, as defined by the ride-through zones in Attachment 1. Critically, momentary cessation is prohibited in the must-ride-through zone — IBRs that historically stopped injecting current during low-voltage events to protect equipment will need to be reconfigured or replaced. After voltage recovery, real power must return to pre-disturbance levels within five cycles.
R2 — Frequency Ride-Through: IBRs must remain online through frequency deviations across a defined range, including continuous operation between 58.8 Hz and 61.2 Hz, and sustained operation through excursions into the 56–57 Hz and 61.8–64 Hz bands for at least 6 seconds. Rate of Change of Frequency (RoCoF) ride-through is required up to 5 Hz/second.
R3 — Current Injection and Voltage Support: During disturbances, IBRs must actively inject current and provide voltage support to the Bulk Power System — not simply stay connected passively. Reactive current priority during voltage events is the default, though Transmission Operators may require active power prioritization instead.
R4 — Hardware Limitation Exemptions: Legacy IBRs already in service before the effective date that physically cannot meet ride-through requirements due to hardware constraints may qualify for a limited exemption — but only with thorough documentation submitted to the Compliance Enforcement Authority, Planning Coordinator, Transmission Planner, and Reliability Coordinator within 12 months of the standard's effective date. This is not a free pass; it is a documented, auditable process with strict evidence requirements.
All compliance documentation and disturbance data must be retained for 3 to 5 years depending on the specific requirement.
Why This Standard Is Different
PRC-029-1 is primarily performance-based — meaning compliance isn't just demonstrated on paper through simulation studies. It has to show up in how your IBRs actually behave during real grid events, validated through the disturbance monitoring data your equipment collects under PRC-028-1. Design compliance and operational compliance are separate tracks, and both require organized, ongoing evidence management.
Add to that the sheer breadth of what needs to be assessed: protection settings, inverter control configurations, Phase-Lock Loop behavior, dynamic model currency, legacy hardware evaluations, exemption documentation, multi-party notifications, and post-event performance records — across potentially dozens of facilities. For compliance teams already stretched thin, this is a significant lift.
Introducing dp: PRC-029
dp: PRC-029 brings data phleet's AI-driven automation to the full compliance lifecycle of PRC-029-1. Our solution:
- Inventories your IBR fleet against PRC-029-1 applicability criteria, distinguishing BES from non-BES assets and flagging those approaching design compliance deadlines
- Tracks design compliance status for each unit — ride-through settings, momentary cessation configuration, current injection capability, and control mode documentation
- Monitors operational compliance by linking to PRC-028-1 disturbance data, automatically flagging events where IBR performance should be reviewed against ride-through requirements
- Manages the R4 exemption process for legacy assets — organizing hardware limitation evidence, tracking submission deadlines, and maintaining audit-ready records of all notifications sent to required parties
- Maintains dated compliance evidence packages for R1 through R4 across your entire fleet, structured for NERC audit readiness from day one
- Alerts your team to post-disturbance review obligations so no grid event becomes a missed compliance action
As always with data phleet, human review stays at the center. dp: PRC-029 handles the tracking, evidence organization, and deadline management so your engineers can focus on the technical decisions — not the administrative burden.
PRC-029-1 is a standard that lives or dies on operational evidence. It's not enough to configure your IBRs correctly and file away a study — you have to demonstrate, event by event, that your fleet is actually performing. That's exactly the kind of continuous, data-intensive compliance work that data phleet was built to automate.