By Kristina Hannum, Senior NERC Reliability Specialist
Understanding PRC-028 & the Unique Challenges for Generator Owners
The NERC Reliability Standard PRC-028-1, titled “Disturbance Monitoring and Reporting Requirements for Inverter-Based Resources,” directly impacts Generator Owners (GO) with solar, wind, battery storage, and other inverter-connected generation facilities. This standard mandates comprehensive data collection and reporting capabilities during grid disturbances, extending beyond simple data collection and providing more sophisticated monitoring and analytical capabilities. So, what impact will this have on Generator Owners? To answer that, we must first take a deeper dive into what PRC-028 really requires.
PRC-028 requires applicable IBR facilities to install, maintain, and operate disturbance monitoring equipment capable of capturing detailed electrical and control system data during specified triggering events. These “monitoring systems” must capture both steady-state and transient behavior of IBRs, including voltage and current measurements; active and reactive power output; inverter control system status; and protection system operations. This requires sophisticated monitoring systems that exceed traditional SCADA capabilities.
The standard further specifies additional data recording requirements, including electrical measurements; control system parameters; and inverter operational data which must be captured with sufficient resolution and duration, to enable meaningful analysis of IBR performance during system events.
While this may sound as though one can “flip a switch” to be compliant, the truth of the matter is that the complexity of modern IBR control systems presents significant implementation hurdles.
Wind turbines with multiple inverters, solar farms with distributed inverter architectures, and battery storage systems with complex power management systems each require tailored monitoring approaches. Additionally, integrating with existing plant control systems presents technical challenges that require careful planning. Monitoring equipment must interface with diverse inverter platforms, communication protocols, and control architecture without compromising operational reliability, all the while ensuring that the monitoring systems can capture data from primary inverter controls, plant-level controllers, and grid-interface equipment simultaneously.
Coordination between original equipment manufacturers (OEMs) and Owners is critical, now more than ever, as many existing IBR installations lack adequate disturbance monitoring capabilities. Some OEMs have long been gone and retrofitting monitoring equipment often requires extended outages, specialized technical expertise, and careful coordination to avoid impacting generation availability.
But wait! There’s more! We haven’t even scratched the surface of data management infrastructure yet, which represents another significant challenge. PRC-028 requires high-resolution data capture that can generate substantial data volumes, necessitating robust data storage, processing, and data transmission capabilities. Meaning Owners must ensure their systems can handle continuous monitoring while providing reliable data retrieval and reporting functionality.
Strategic Implementation Approaches
So how does an entity even begin to handle tackling such a large, demanding, implementation? Any successful implementation requires a phased, systematic approach that prioritizes critical system areas while building towards full compliance. Leading entities have adopted comprehensive project management frameworks that address technical, operational, and regulatory requirements simultaneously. Simply put, with a very strategic phased approach, piece by piece.
The initial phase typically involves stake holder engagement, resource planning, and conducting detailed system studies that include a comprehensive assessment of existing generator capabilities, identifying system inventory and gaps pertaining thereof. This analysis must consider both steady-state and dynamic system conditions, incorporating various contingency scenarios.
Following the analytical phase, entities should prioritize facilities based on system impact and reliability benefits. Critical generating units that provide essential reliability services or serve load pockets may require expedited compliance measures, while other units may be addressed through longer-term improvement programs.
Generator Owners must carefully balance compliance costs with system reliability benefits when developing PRC-028 implementation strategies. Economic analysis should consider not only direct equipment costs but also outage expenses, ongoing maintenance requirements, and potential revenue impacts from enhanced grid support services.
Compliance Extension Requests: When and How
Despite best efforts, some utilities may find that achieving full PRC-028 compliance within the established timeframe presents insurmountable challenges. In such cases, requesting a compliance extension may be necessary and appropriate; and yes, PRC-028 does allow for compliance implementation extensions. However, these requests must be well-substantiated and demonstrate good faith efforts toward compliance.
Valid grounds for extension requests typically include technical challenges beyond the entity’s control, such as equipment delivery delays, local regulatory approval processes, or coordination difficulties with third parties. Financial constraints alone generally do not constitute sufficient justification, though demonstrated resource allocation toward compliance efforts strengthens any request.
Extension requests should include detailed project timelines, specific implementation challenges encountered, mitigation measures already undertaken, and realistic completion schedules. Documentation of progress made toward compliance and ongoing efforts demonstrates commitment to achieving the standard’s reliability objectives.
When preparing extension requests, entities should engage early with their Regional Entity and maintain transparent communication throughout the process. Requests submitted well before compliance deadlines are generally viewed more favorably than last-minute appeals.
Entities should also demonstrate how lessons learned from the implementation process will improve future compliance efforts and contribute to overall system reliability. This forward-looking perspective helps regulatory bodies understand the long-term value of granting extensions.
Conclusion
PRC-028 implementation represents a significant undertaking that requires careful planning, stakeholder coordination, and technical expertise. While compliance extensions should be requested judiciously, they can provide necessary flexibility when legitimate implementation challenges arise. The key to successful outcomes lies in proactive planning, transparent communication with regulators, and unwavering commitment to the standard’s underlying reliability objectives.
Entities that approach PRC-028 implementation strategically, while maintaining open dialogue with regulatory bodies about potential challenges, position themselves for successful compliance while contributing to overall Bulk Electric System reliability. The standard’s complexity demands respect, but with proper planning and execution, it represents an important step forward in preventing voltage collapse events that could have catastrophic consequences for electric grid reliability.
