Introduction
Inverter-Based Resources (IBRs) have become common in the Bulk Power System (BPS) within North America, playing a critical role in meeting clean energy demands. The unique operational characteristics of IBRs, however, present new challenges to grid stability and reliability. For dealing with dangers related to protection, control, and performance that emerge as a result of such dynamics, the North American Electric Reliability Corporation (NERC) has developed several requirements within its Protection and Control (PRC) series of standards. These include new standards PRC-028, PRC-029, and PRC-030. Together, these standards address disturbance monitoring, inverter performance during system events, and mitigation of unexpected IBR behavior.
PRC-028-1: Disturbance Monitoring and Reporting Requirements for Inverter-Based Resources
PRC-028 establishes new requirements for IBRs to ensure that disturbance data is available for evaluating ride-through performance and supporting model validation. It applies to Generator Owners(GO) of both Bulk Electric System (BES) and qualifying non-BES IBRs with a nameplate rating of 20 MVA or greater that interconnect at 60 kV or above, ensuring that disturbance monitoring and reporting requirements cover all material IBRs impacting system reliability. Standard PRC-028 became effective on April 01, 2025.
Key Compliance Requirements
The following requirements define the core monitoring and recording obligations for Generator Owners:
- Generator Owners must document Sequence of Event Recording (SER) data for IBRs, including breaker status, fault codes, alarms, and ride-through status where applicable.
- Generator Owners must maintain Fault Recording (FR) data at main transformers, collector feeders, and reactive devices. Recordings must activate upon voltage, frequency, and overcurrent events.
- Continuous Dynamic Disturbance Recording (DDR) is required for voltage, current, power, and frequency at specified locations. All SER, FR, and DDR data must be time-synchronized to Coordinated Universal Time for accurate event correlation.
Data Retention and Reporting Obligations
The table below summarizes the key data retention, reporting, and corrective action obligations for Generator Owners.
| Compliance Obligation | Required Action |
|---|---|
|
Data Retention |
Disturbance data must be retrievable for 20 calendar days. |
|
Data Submission |
Requested data must be provided within 15 calendar days. |
|
Data Submission |
CSV or IEEE COMTRADE formats are required. |
|
Recording Failures |
Restore recording capability or submit a Corrective Action Plan (CAP) within 90 calendar days. |
|
Evidence Retention |
Compliance evidence must be retained for three years. |
PRC-029-1: Frequency and Voltage Ride-Through Requirements for Inverter-Based Resources
PRC-029-1 establishes mandatory requirements to ensure IBRs remain connected and support the BPS during defined voltage and frequency disturbances. PRC-029-1 becomes effective on October 01, 2026.
Key Compliance Requirements
The following requirements define how IBRs must perform during voltage and frequency disturbances:
- Generator Owners must ensure that IBRs ride through defined voltage and frequency excursions within the required operating zones.
- The IBRs must continue delivering real and reactive power during voltage disturbances, subject to specified limits and priority rules.
- The IBRs must meet frequency ride-through requirements, including tolerance for frequency excursions.
- Generator Owners must retain disturbance monitoring data to demonstrate actual ride-through performance.
Hardware Limitation Exception
PRC-029 allows a limited exception for IBRs that were in service by the effective date and cannot meet ride-through requirements because of verified hardware limitations. The limitation must be hardware-based and not resolvable through software or setting changes. Once the limiting hardware is replaced, the exception no longer applies.
Documentation and Reporting Obligations
The table below summarizes additional compliance obligations related to hardware limitations, documentation, and evidence retention:
| Compliance Obligation | Required Action |
|---|---|
|
Information Sharing |
Provide hardware limitation documentation to applicable planning and operating entities, as well as the Compliance Enforcement Authority. |
|
Requests for Information |
Respond to additional information requests from applicable entities within 90 days. |
|
Hardware Replacement |
Communicate the replacement of limiting hardware within 90 days, after which the exemption no longer applies. |
|
Evidence Retention |
Retain compliance evidence for 36 months and five years for approved hardware limitations. |
PRC-030-1: Unexpected Inverter-Based Resource Event Mitigation
PRC-030-1 establishes requirements to identify, analyze, and mitigate unexpected changes in real power output from IBRs to reduce system-wide reliability risks. Standard PRC-030-1 becomes effective on October 01, 2026.
Key Compliance Requirements
The following requirements define how Generator Owners must detect, analyze, and mitigate unexpected IBR events:
- Generator Owners must detect unexpected real power changes of 20 MW and 10 percent of the gross nameplate rating within 4 seconds.
- Within 90 calendar days of an event or request, Generator Owners must analyze the event, identify root causes, document performance, and assess applicability to other facilities.
- If issues are identified, Generator Owners must develop a CAP or provide a technical justification within 60 calendar days of completing the analysis.
- Generator Owners must implement the CAP, update it if actions or timelines change, and notify applicable Reliability Coordinators(RC) when updates occur or when the CAP is completed.
Documentation and Reporting Obligations
The table below summarizes documentation, mitigation, and evidence retention obligations following an unexpected IBR event:
| Compliance Obligation | Required Action |
|---|---|
|
Event Analysis |
Complete and document event analysis within 90 calendar days. |
|
Corrective Action Plan (CAP) |
Complete and document event analysis within 90 calendar days. |
|
CAP Communication |
Provide CAP or justification to the Reliability Coordinator, Balancing Authority, and Transmission Operator. |
|
CAP Implementation |
Implement and update CAP; notify entities of changes or completion. |
|
Evidence Retention |
Retain compliance evidence for 36 months. |
Certain routine or planned power changes, including those caused by normal variability in wind or solar resources, planned outages or testing, dispatch or ramping actions, and transmission or collection system losses, are excluded from PRC-030 event analysis requirements.
IBR Compliance Implementation Roadmap
The table below outlines a structured approach for implementing and sustaining IBR compliance with PRC-028, PRC-029, and PRC-030:
| Roadmap Stage | What to Do | Related PRC Standard(s) |
|---|---|---|
|
Gap Assessment |
Compare existing monitoring, modeling, and event response practices against PRC requirements. |
PRC-028, PRC-029, and PRC-030 |
|
Disturbance Monitoring Readiness |
Confirm disturbance monitoring, recording, time synchronization, and data retention capabilities are in place. |
PRC-028 |
|
Model Validation and Performance Alignment |
Confirm disturbance monitoring, recording, time synchronization, and data retention capabilities are in place. |
PRC-029 |
|
Event Detection and Analysis |
Detect qualifying unexpected real power changes and analyze IBR performance. |
PRC-030 |
|
Corrective Action and Verification |
Develop and implement corrective actions or technical justifications and verify resolution. |
PRC-030 |
|
Training and Documentation |
Ensure operations, engineering, and compliance teams understand requirements and documentation expectations. |
PRC-028, PRC-029, and PRC-030 |
Best Practices for Sustainable Compliance
Take action now to ensure compliance. Register your inverter-based resources with Certrec and avoid last-minute risk. Visit www.certrec.com to learn more and secure your NERC compliance today.
The following practices reflect common industry approaches for meeting and sustaining compliance with NERC inverter-based resource standards:
- Integrate IBR requirements into existing protection and model management programs.
- Conduct cross-functional reviews across protection, modeling, operations, and compliance teams.
- Use automated monitoring and disturbance analysis tools to support validation and reporting.
- Apply a continuous improvement approach by reviewing post-disturbance data and corrective actions.
Conclusion
The PRC-028, PRC-029, and PRC-030 standards mark a major shift in IBR monitoring, validation, and control within BPS. They constitute an integrated compliance approach that spans monitoring, performance, and disturbance mitigation. It is better formulated as a consideration within a single integrated program rather than an individual obligation. This approach supports clearer compliance demonstrations, more effective responses to system events, and reliable grid operations as inverter-based resources continue to expand.
For information on how Certrec can assist with NERC compliance, visit www.certrec.com or contact us at NERCExperts@certrec.com.
