THE LINE BETWEENPRC-023/PRC-025

What generator Owners need to know!

Daniel J HansenNRG Energy, Inc.3/31/2015

NERC Regions are separate Compliance Organizations.

Compliance Executed by Region

Clearly Needed are corrective actions to lessen the reliability impact of load responsive relays: avoid unnecessary cascading outages.

WHY RELAY LOADABILITY STANDARDS ARE IMPORTANT

2003 BLACKOUT• Transmission Lines Tripped for reasons other than clearing a

fault. Cascading separation and outages are caused by load responsive relays.

• 290 Generating Units Tripped (approximately 52,745 MW). The Primary Reason: the operation of protection relays for units connected to a system in distressed condition. As generating units trip prematurely, the cascading impact is accelerated.

TIMELINE of APPROVAL for RELAY LOADABILITY STANDARDS

• PRC-023-1 FERC ORDER 733 3/18/2010

• PRC-023-2 FERC ORDER 759 3/15/2012

• PRC-023-3 FERC ORDER 799 7/17/2014PRC-025-1

FERC ORDER 733

Applicability of PRC-023 as directed by FERC in Order No. 733, provides very explicit wording for application. Protection of specific Transmission is included; Generator Owner Facilities are excluded.

Compliance Scope Growth Reaching Into GO Facilities

HV GENERATION INTERCONNECTION

GENERATIONFACILITIES

PRC-023

Generator Owners contributed to the overreach either by ignorance or passive submission.

Generator Owners are included in the applicability section of the PRC-023 standard, even though protection of Generator Owner Facilities are excluded.

PRC-023 APPLICABILITY

TRANSMISSION OWNERS GENERATOR OWNERS

PRC-023 Requirements

WHAT SHOULD HAVE BEEN CLEAR TO SEE, BECAME BLURRED

• Generator Owners are included in the applicability section of PRC-023-1

• FERC recognized that Generator Relay Loadability is a complex issue; it presents distinctly different challenges

• PRC-023 applies to the Protection of Transmission Elements, regardless if primary or backup protection and regardless of physical location of the relay.

• FERC identified that Distance Back-up Protection located at Generating Units can be applied in two wayso Transmission Elements (as defined by applicability)o Generator and GSU

• Therefore, Relays for Transmission Protection located at a generating unit are within PRC-023 applicability.

FERC ORDER 733: WHERE DOES THE CONFUSION START?

Progression of “False” Logic• Generator Owners are in

applicability Section• Transmission Lines over

200kV are included in scope of PRC-023

• High Voltage Overhead Conductors are Transmission lines

• Generator Owner’s high voltage overhead conductors are Transmission lines

• Relays on those lines are in the scope of PRC-023

Further Complications - Incorrect Interpretation

PRC-023-1 applies: protection for transmission elements, regardless of physical location of relay, includes within scope.

CRUCIAL ISSUE - WHAT IS PROTECTED & BY WHOM

Generator Owner Transmission Owner

One Utility with GO & TO Registrations. Distance elements on generating units are integrated into backup transmission protection schemes.

Generator Owner & Transmission Owner have an obligation to coordinate, but no obligation to protect each other’s facilities.

CRUCIAL ISSUE - WHAT IS PROTECTED & BY WHOM

Generator Owner Transmission Owner

The GO & TO are independent. PRC-023 DOES NOT APPLY for GO distance elements, regardless of the reach into the transmission system. PRC-025-1 will apply to GO protection.

PRC-023 does not apply to Generator Owner, if GO high voltage facilities existing exist only for generation interconnection.

GENERATOR OWNER’S HV FACILITIES

Generator OwnerTransmission Owner

There was never an intentional blurring of the lines• FERC is abundantly clear, with no ambiguity, there is to be a

separation of transmission and generation loadable relays into different standards.

• PRC-023-1 excludes Generator relays susceptible to load; Generator step-up transformer relay loadability is intentionally omitted

• Generator, step-up and auxiliary transformer loadability will get address by NERC in a future reliability standard.

• FERC acknowledges “generator step-up and auxiliary transformer loadability” and “generator relay loadability” all to refer to the same thing.

FERC ORDER 733 ESTABLISHES A BRIGHT LINE

FERC Order No. 733

“Therefore, no generator owner that is not also atransmission owner and/or a distributionprovider will be subject to PRC-023-1.”

A DEFINITIVE, BRIGHT LINE OF SEPARATION

… (PRC-023-1) applies to facilities 100 kV above and to transformers with low-voltage terminals 200 kV and above. Because there are no commercial generators with a terminal voltage as high as 100 kV and all generator step-up and auxiliary power transformers have low-voltage windings well below 200 kV, PRC-023-1 excludes generators and all generator step-up and auxiliary transformers. Therefore, no generator owner that is not also a transmission owner and/or a distribution provider will be subject to PRC-023-1.

NERC COMPLIANCE PROCESS BULLETIN #2012-001

Clarifies the Separation between the Two StandardsPRC-023-3 Applicability:

Transmission lines operated at 200 kV and above, except Elements that connect the GSU transformer(s) to theTransmission system that are used exclusively to export energy directly from a BES generating unit or generatingplant.

PRC-025-1 Applicability:The converse of PRC-023-3 applicability is applied.

FERC Order No. 799:There is no compliance overlap between PRC-023-3 and PRC-025-1, i.e. the same relay element does not come under the requirements of both standards.

PRC-023-3 & PRC-025-1 DEVELOPMENT

1. All Versions of PRC-023 apply to protection of the networked Transmission Owner’s BES Facilities defined within applicability section , not Generator Owner’s equipment and circuits.

2. From the beginning, the application of PRC-023 to a Generator Owner was intentionally limited, restricted to relays protecting Transmission Owner Facilities.

3. FERC Order Nos. 733 and 733A each state in clear, unambiguous terms “no generator owner that is not also a transmission owner and/or a distribution provider will be subject to PRC-023-1.”

4. There is No Applicability Overlap between PRC-023 & PRC-025. A single relay is limited to the scope of one standard, but not both. Protection of Generator Interconnection Facilities was never intended to first comply with PRC-023, then later transition to PRC-025.

SUMMARY

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