A Coordinated Electric System Interconnection Review—the utility’s deep-dive on technical and cost impacts of your project.

Challenge: Frequent false tripping using conventional electromechanical relays
Solution: SEL-487E integration with multi-terminal differential protection and dynamic inrush restraint
Result: 90% reduction in false trips, saving over $250,000 in downtime

The electric power industry is entering a new reliability era driven by the rapid growth of inverter-based resources (IBRs). Solar photovoltaic plants, battery energy storage systems (BESS), wind facilities, and hybrid renewable projects are no longer considered peripheral contributors to the North American grid. They are now central to generation adequacy, system stability, and operational reliability.

As the penetration of inverter-based generation increases, the Federal Energy Regulatory Commission (FERC) and the North American Electric Reliability Corporation (NERC) have fundamentally changed the compliance landscape through the Category 2 IBR Registration Initiative.

Beginning May 15, 2026, qualifying non-BES inverter-based resources connected to the Bulk Power System (BPS) will become subject to mandatory NERC registration and compliance requirements. For many owners and operators, this represents the first time they will operate within the NERC Compliance Monitoring and Enforcement Program (CMEP).

Keentel Engineering provides comprehensive Category 2 IBR compliance services designed to help asset owners navigate this evolving regulatory environment with technical precision and operational confidence.

Category 2 registration applies to non-BES inverter-based generating resources that:

Have or contribute to an aggregate gross nameplate capacity of 20 MVA or greater
Are connected through a system designed primarily for delivering power to a common point of connection
Are interconnected at 60 kV or greater

This includes:

Solar PV plants
Wind generation facilities (Type 3 and Type 4)
Battery Energy Storage Systems (BESS)
Hybrid renewable facilities
Co-located inverter-based resources

Historically, many of these facilities operated outside mandatory NERC Reliability Standards because they did not meet the BES definition. However, NERC determined these resources could materially impact bulk power system reliability and therefore required regulatory oversight.

Keentel Engineering evaluates whether facilities qualify under Category 2 registration thresholds.

Our assessments include:

Aggregate MVA analysis
Hybrid resource evaluation
Point of interconnection review
Voltage threshold analysis
BES and non-BES determination
Aggregation boundary review

This process is critical because incorrect applicability assumptions can lead to:

Registration failures
Expanded compliance scope
Enforcement exposure
Audit findings

GO/GOP Functional Role Mapping

One of the most misunderstood aspects of Category 2 registration is the distinction between:

Generator Owner (GO)
Generator Operator (GOP)

Keentel Engineering performs detailed functional responsibility evaluations to identify:

Asset ownership responsibilities
Operational control responsibilities
Third-party operator obligations
Joint ownership exposure
Registration coordination requirements

This becomes particularly important in:

Hybrid facilities
Tax equity structures
Asset-managed projects
Third-party operations agreements

CMEP-Ready Documentation Development

Regional Entities are heavily relying on documentation during registration and compliance evaluations.

Keentel Engineering develops:

Single-line diagrams
Registration support packages
Functional relationship diagrams
Interconnection documentation reviews
Asset verification spreadsheets
Compliance evidence repositories

Our documentation approach aligns with:

ERO Enterprise CMEP Practice Guide
NERC registration RFIs
Regional Entity audit expectations

Reliability Standards Gap Analysis

Keentel Engineering helps clients understand which Reliability Standards currently apply and which future standards may become applicable.

Current enforceable standards include:

BAL-001-TRE-2
IRO-010-5
MOD-032-1
PRC-012-2
PRC-017-1
TOP-003-6.1
VAR-001-5
VAR-002-4.1

Future evolving standards include:

PRC-028-1
PRC-029-1
PRC-030-1
MOD-026
MOD-033
EMT modeling requirements

IBR Modeling and Order No. 901 Engineering Support

FERC Order No. 901 significantly expands technical obligations for inverter-based resources.

Keentel Engineering supports:

Dynamic model validation
MOD-032 data preparation
PSCAD studies
EMT modeling
Ride-through assessments
Disturbance monitoring evaluations
PRC-029 readiness
PRC-028 event recording support

These services help clients align with:

Model validation requirements
Planning study expectations
Reliability coordinator data needs
Future NERC standards

Case Study 1 – Solar + BESS Hybrid Registration Assessment

Challenge

A utility-scale solar developer operating a 150 MW solar PV facility with a co-located 80 MW BESS system needed to determine whether the hybrid configuration triggered Category 2 registration obligations.

The client faced uncertainty regarding:

Aggregation methodology
DC-coupled versus AC-coupled evaluation
Ownership responsibility allocation
GOP designation

Keentel Engineering Solution

Keentel Engineering conducted:

Aggregation boundary analysis
Single-line diagram review
Gross aggregate MVA evaluation
Functional GO/GOP responsibility mapping
CMEP Practice Guide alignment review

Outcome

Keentel Engineering identified that the hybrid facility met Category 2 applicability thresholds and developed:

Registration support documentation
Updated one-line diagrams
Functional registration matrix
Compliance readiness roadmap

The client successfully initiated Regional Entity coordination with reduced registration risk.

Case Study 2 – Wind Facility PRC-029 Readiness Review

Challenge

A wind generation owner operating multiple Type 4 wind facilities needed to evaluate future PRC-029 ride-through compliance obligations.

The owner lacked:

Verified inverter ride-through settings
Disturbance response documentation
PPC coordination validation
Dynamic model consistency

Keentel Engineering Solution

Keentel Engineering performed:

Ride-through capability assessment
Inverter control evaluation
Dynamic model review
Protection coordination assessment
Voltage and frequency tolerance analysis

Outcome

The client received:

PRC-029 readiness gap report
Recommended settings adjustments
Compliance evidence templates
Future modeling roadmap

The project significantly reduced future enforcement and operational risk.

Case Study 3 – Multi-Owner Hybrid Registration Support

Challenge

Two independent entities jointly owned a solar + storage hybrid project interconnected at 115 kV.

The owners incorrectly assumed only one entity required registration.

Keentel Engineering Solution

Keentel Engineering analyzed:

Functional ownership responsibilities
Common point of interconnection
Aggregate MVA contribution
GOP operational obligations

Outcome

Keentel Engineering determined both owners required Category 2 GO registration and developed:

Registration coordination strategy
Compliance role matrix
Supporting technical documentation

This prevented future registration conflicts and potential compliance violations.

FAQ 1: How is gross aggregate nameplate capacity calculated for Category 2 IBRs?
Gross aggregate nameplate capacity is determined using the apparent power rating (MVA) of inverter equipment contributing to the common point of connection. Operational limitations, export restrictions, and dispatch constraints are generally not considered in the calculation.
FAQ 2: Do reactive compensation devices count toward Category 2 aggregation thresholds?
No. Dynamic or static reactive devices such as STATCOMs, capacitor banks, and reactors do not contribute toward gross aggregate nameplate capacity calculations.
FAQ 3: Can separate ownership structures avoid Category 2 applicability?
No. Ownership does not eliminate aggregation obligations. Multiple owners contributing to the same qualifying common point of connection may each require registration.
FAQ 4: How are DC-coupled solar and BESS systems evaluated?
DC-coupled systems are evaluated based on the inverter-based export capability delivered through the common point of interconnection. Certain DC/DC converter ratings may not independently contribute toward aggregation totals depending on configuration.
FAQ 5: Why are EMT studies becoming more important for IBRs?
EMT studies are increasingly necessary because inverter controls operate on very fast timescales that traditional transient stability models cannot fully represent. Weak grid conditions, inverter interactions, and protection issues often require EMT analysis.
FAQ 6: What is the relationship between PRC-028 and model validation?
PRC-028 disturbance monitoring requirements support event analysis and provide data necessary for validating dynamic and EMT models following grid disturbances.
FAQ 7: How does PRC-029 affect inverter settings?
PRC-029 requires IBRs to maintain ride-through capability during abnormal frequency and voltage conditions. This often requires coordination between inverter firmware, plant power controllers, and protection settings.
FAQ 8: What is the purpose of MOD-032 for Category 2 IBRs?
MOD-032 ensures planners and operators receive accurate modeling data necessary for power system analysis and reliability assessments.
FAQ 9: Why are Regional Entities requesting one-line diagrams during registration?
Single-line diagrams are used to evaluate:

Aggregation boundaries
Voltage levels
Common points of connection
Functional relationships
Hybrid resource configurations

These diagrams directly affect applicability determinations.
FAQ 10: What is considered the common point of connection?
The common point of connection is generally where the collector system connects to the 60 kV or higher Bulk Power System. This location is often identified in interconnection agreements.
FAQ 11: Can a BESS alone trigger Category 2 registration?
Yes. A standalone battery energy storage system interconnected at 60 kV or higher with aggregate inverter capacity of 20 MVA or greater may independently qualify as a Category 2 resource.
FAQ 12: How does hybrid aggregation differ from BES aggregation?
Category 2 aggregation focuses specifically on inverter-based resources and does not aggregate with synchronous generation for registration threshold determination.
FAQ 13: What are the biggest engineering risks for Category 2 entities?
Common risks include:

Inaccurate models
Improper ride-through settings
Incomplete documentation
Protection coordination errors
Failure to understand aggregation rules
FAQ 14: Why is model validation becoming a regulatory priority?
Multiple grid events demonstrated that modeled IBR behavior often differed significantly from actual field performance, creating planning and operational reliability concerns.
FAQ 15: How does Keentel Engineering support technical compliance?
Keentel Engineering combines NERC compliance expertise with:

Power system studies
Protection engineering
Dynamic modeling
EMT analysis
Registration strategy
Audit readiness

This integrated approach helps clients manage both technical and regulatory risk.

In 1995, Sonny Patel earned his Electrical Engineering degree from the University of Illinois. But degrees don't build legacies — action does.

For three decades, he has worked the power industry from every side of the table: 16 years as a utility engineer at Exelon/Commonwealth Edison; generation leadership across hydroelectric, industrial steam turbine, and a 9 GW renewable fleet; NERC Regional Entity Senior Compliance Engineer and Audit Team Lead, auditing some of the nation's largest utilities; and testing and commissioning lead on equipment up to 765 kV — the very top of the North American grid.Utility. Generator. Regulator. Consultant. Few engineers have seen all four seats. Fewer still have sat in them.

His experience spans nuclear, hydro, conventional generation, renewables, oil and gas, mining — and today's data centers, where he is authoring a three-book series on data center design. He is a Licensed Professional Engineer in six states and a Licensed Electrical Contractor in Florida (Unlimited EC) — he doesn't just design the work; he's qualified to stand behind its execution.Today, as Founder and CEO of Keentel Engineering, Sonny leads a nationwide team of engineers delivering substation design, power system studies, NERC compliance, and commissioning — done right, coast to coast.Three decades. Every side of the table. One standard: accountable engineering.

In 1995, Sonny Patel earned his Electrical Engineering degree from the University of Illinois. But degrees don't build legacies — action does.

Utility. Generator. Regulator. Consultant. Few engineers have seen all four seats. Fewer still have sat in them.

Today, as Founder and CEO of Keentel Engineering, Sonny leads a nationwide team of engineers delivering substation design, power system studies, NERC compliance, and commissioning — done right, coast to coast.Three decades. Every side of the table. One standard: accountable engineering.