PRC-019-1 Rel Standard

Standard PRC-019-1 — Coordination of Generating Unit or Plant Capabilities, Voltage
Regulating Controls, and Protection
A. Introduction
1.

Title:
Coordination of Generating Unit or Plant Capabilities, Voltage Regulating
Controls, and Protection

2.

Number:

3.

Purpose: To verify coordination of generating unit Facility or synchronous
condenser voltage regulating controls, limit functions, equipment capabilities and
Protection System settings.

4.

Applicability:

PRC-019-1

4.1. Functional Entities

4.1.1

Generator Owner

4.1.2

Transmission Owner that owns synchronous condenser(s)

4.2. Facilities

For the purpose of this standard, the term, “applicable Facility” shall mean any
one of the following:

5.

4.2.1

Individual generating unit greater than 20 MVA (gross nameplate rating)
directly connected to the Bulk Electric System.

4.2.2

Individual synchronous condenser greater than 20 MVA (gross nameplate
rating) directly connected to the Bulk Electric System.

4.2.3

Generating plant/ Facility consisting of one or more units that are
connected to the Bulk Electric System at a common bus with total
generation greater than 75 MVA (gross aggregate nameplate rating).

4.2.4

Any generator, regardless of size, that is a blackstart unit material to and
designated as part of a Transmission Operator’s restoration plan.

Effective Date:
5.1. In those jurisdictions where regulatory approval is required:

5.1.1

By the first day of the first calendar quarter, two calendar years following
applicable regulatory approval, or as otherwise made effective pursuant to
the laws applicable to such ERO governmental authorities, each Generator
Owner and Transmission Owner shall have verified at least 40 percent of
its applicable Facilities.

5.1.2

By the first day of the first calendar quarter, three calendar years following
applicable regulatory approval, or as otherwise made effective pursuant to
the laws applicable to such ERO governmental authorities, each Generator
Owner and Transmission Owner shall have verified at least 60 percent of
its applicable Facilities.

5.1.3

By the first day of the first calendar quarter, four calendar years following
applicable regulatory, or as otherwise made effective pursuant to the laws
applicable to such ERO governmental authorities, approval each

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Standard PRC-019-1 — Coordination of Generating Unit or Plant Capabilities, Voltage
Regulating Controls, and Protection

Generator Owner and Transmission Owner shall have verified at least 80
percent of its applicable Facilities.
5.1.4

By the first day of the first calendar quarter, five calendar years following
applicable regulatory approval, or as otherwise made effective pursuant to
the laws applicable to such ERO governmental authorities, each Generator
Owner and Transmission Owner shall have verified 100 percent of its
applicable Facilities.

5.2. In those jurisdictions where regulatory approval is not required:

5.2.1

By the first day of the first calendar quarter, two calendar years following
Board of Trustees approval, or as otherwise made effective pursuant to the
laws applicable to such ERO governmental authorities, each Generator
Owner and Transmission Owner shall have verified at least 40 percent of
its applicable Facilities.

5.2.2

By the first day of the first calendar quarter, three calendar years following
Board of Trustees approval, or as otherwise made effective pursuant to the
laws applicable to such ERO governmental authorities, each Generator
Owner and Transmission Owner shall have verified at least 60 percent of
its applicable Facilities.

5.2.3

By the first day of the first calendar quarter, four calendar years following
Board of Trustees approval, or as otherwise made effective pursuant to the
laws applicable to such ERO governmental authorities, each Generator
Owner and Transmission Owner shall have verified at least 80 percent of
its applicable Facilities.

5.2.4

By the first day of the first calendar quarter, five calendar years following
Board of Trustees approval, or as otherwise made effective pursuant to the
laws applicable to such ERO governmental authorities, each Generator
Owner and Transmission Owner shall have verified 100 percent of its
applicable Facilities.

B. Requirements
R1.

At a maximum of every five calendar years, each Generator Owner and Transmission
Owner with applicable Facilities shall coordinate the voltage regulating system
controls, (including in-service1 limiters and protection functions) with the applicable
equipment capabilities and settings of the applicable Protection System devices and
functions. [Violation Risk Factor: Medium] [Time Horizon: Long-term Planning]
1.1. Assuming the normal automatic voltage regulator control loop and steady-state

system operating conditions, verify the following coordination items for each
applicable Facility:

1

Limiters or protection functions that are installed and activated on the generator or synchronous condenser.
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Standard PRC-019-1 — Coordination of Generating Unit or Plant Capabilities, Voltage
Regulating Controls, and Protection

R2.

1.1.1.

The in-service limiters are set to operate before the Protection System of
the applicable Facility in order to avoid disconnecting the generator
unnecessarily.

1.1.2.

The applicable in-service Protection System devices are set to operate to
isolate or de-energize equipment in order to limit the extent of damage
when operating conditions exceed equipment capabilities or stability
limits.

Within 90 calendar days following the identification or implementation of systems,
equipment or setting changes that will affect the coordination described in Requirement
R1, each Generator Owner and Transmission Owner with applicable Facilities shall
perform the coordination as described in Requirement R1. These possible systems,
equipment or settings changes include, but are not limited to the following [Violation
Risk Factor: Medium] [Time Horizon: Long-term Planning]:


Voltage regulating settings or equipment changes;



Protection System settings or component changes;



Generating or synchronous condenser equipment capability changes; or



Generator or synchronous condenser step-up transformer changes.

C. Measures
M1. Each Generator Owner and Transmission Owner with applicable Facilities will have

evidence (such as examples provided in PRC-019 Section G) that it coordinated the
voltage regulating system controls, including in-service2 limiters and protection
functions, with the applicable equipment capabilities and settings of the applicable
Protection System devices and functions as specified in Requirement R1. This
evidence should include dated documentation that demonstrates the coordination was
performed. 
M2. Each Generator Owner and Transmission Owner with applicable Facilities will have

evidence of the coordination required by the events listed in Requirement R2. This
evidence should include dated documentation that demonstrates the specified intervals
in Requirement R2 have been met.
D. Compliance
1.

Compliance Monitoring Process
1.1. Compliance Enforcement Authority

The Regional Entity shall serve as the Compliance enforcement authority unless
the applicable entity is owned, operated, or controlled by the Regional Entity. In
such cases the ERO or a Regional entity approved by FERC or other applicable
governmental authority shall serve as the CEA.

2

Limiters or protection functions that are installed and activated on the generator or synchronous condenser.
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Standard PRC-019-1 — Coordination of Generating Unit or Plant Capabilities, Voltage
Regulating Controls, and Protection
1.2. Evidence Retention

The following evidence retention periods identify a period of time an entity is
required to retain specific evidence to demonstrate compliance. For instances
where the evidence retention specified below is shorter than the time since the last
compliance audit, the Compliance Enforcement Authority may ask an entity to
provide other evidence to show that it was compliant for the full time period since
the last audit.
The Generator Owner and Transmission Owner shall retain evidence of
compliance with Requirements R1 and R2, Measures M1 and M2 for six years.
If a Generator Owner or Transmission Owner is found non-compliant, the entity
shall keep information related to the non-compliance until mitigation is complete
and approved or for the time period specified above, whichever is longer.
The Compliance Enforcement Authority shall keep the last periodic audit report
and all requested and submitted subsequent audit records.
1.3. Compliance Monitoring and Assessment Processes

Compliance Audit
Self-Certification
Spot Checking
Compliance Investigation
Self-Reporting
Complaint
1.4. Additional Compliance Information

None
2.

Violation Severity Levels
R#
R1

Lower VSL

Moderate VSL

High VSL

Severe VSL

The Generator
Owner or
Transmission Owner
coordinated
equipment
capabilities, limiters,
and protection
specified in
Requirement R1
more than 5 calendar

The Generator
Owner or
Transmission Owner
coordinated
equipment
capabilities, limiters,
and protection
specified in
Requirement R1
more than 5 calendar

The Generator
Owner or
Transmission Owner
coordinated
equipment
capabilities, limiters,
and protection
specified in
Requirement R1
more than 5 calendar

The Generator
Owner or
Transmission Owner
failed to coordinate
equipment
capabilities, limiters,
and protection
specified in
Requirement R1
within 5 calendar
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Standard PRC-019-1 — Coordination of Generating Unit or Plant Capabilities, Voltage
Regulating Controls, and Protection

R2

years but less than or
equal to 5 calendar
years plus 4 months
after the previous
coordination.

years plus 4 months
but less than or equal
to 5 calendar years
plus 8 months after
the previous
coordination.

years plus 8 months
but less than or equal
to 5 calendar years
plus 12 months after
the previous
coordination.

years plus 12 months
after the previous
coordination.

The Generator
Owner or
Transmission Owner
coordinated
equipment
capabilities, limiters,
and protection
specified in
Requirement R1
more than 90
calendar days but
less than or equal to
100 calendar days
following the
identification or
implementation of a
change in equipment
or settings that
affected the
coordination.

The Generator
Owner or
Transmission Owner
coordinated
equipment
capabilities, limiters,
and protection
specified in
Requirement R1
more than 100
calendar days but
less than or equal to
110 calendar days
following the
identification or
implementation of a
change in equipment
or settings that
affected the
coordination.

The Generator
Owner or
Transmission Owner
coordinated
equipment
capabilities, limiters,
and protection
specified in
Requirement R1
more than 110
calendar days but
less than or equal to
120 calendar days
following the
identification or
implementation of a
change in equipment
or settings that
affected the
coordination.

The Generator
Owner or
Transmission Owner
failed to coordinate
equipment
capabilities, limiters,
and protection
specified in
Requirement R1
within 120 calendar
days following the
identification or
implementation of a
change in equipment
or settings that
affected the
coordination.

E. Regional Variances

None.
F. Associated Documents

“Underexcited Operation of Turbo Generators”, AIEE Proceedings T Section 881, Volume
67, 1948, Appendix 1, C. G. Adams and J. B. McClure.
,”Protective Relaying For Power Generation Systems”, Boca Raton, FL, Taylor & Francis,
2006, Reimert, Donald
“Coordination of Generator Protection with Generator Excitation Control and Generator
Capability”, a report of Working Group J5 of the IEEE PSRC Rotating Machinery
Subcommittee
“IEEE C37.102-2006 IEEE Guide for AC Generator Protection”
“IEEE C50.13-2005 IEEE Standard for Cylindrical-Rotor 50 Hz and 60 Hz Synchronous
Generators Rated 10 MVA and Above”

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Standard PRC-019-1 — Coordination of Generating Unit or Plant Capabilities, Voltage
Regulating Controls, and Protection

Version History
Version
1

Date

Action

February 7, 2013

Adopted by NERC Board of Trustees

Change Tracking
New

G. Reference

Examples of Coordination
The evidence of coordination associated with Requirement R1 may be in the form of:


P-Q Diagram (Example in Attachment 1), or



R-X Diagram (Example in Attachment 2), or



Inverse Time Diagram (Example in Attachment 3) or,



Equivalent tables or other evidence

This evidence should include the equipment capabilities and the operating region for the
limiters and protection functions
Equipment limits, types of limiters and protection functions which could be coordinated
include (but are not limited to):


Field over-excitation limiter and associated protection functions.



Inverter over current limit and associated protection functions.



Field under-excitation limiter and associated protection functions.



Generator or synchronous condenser reactive capabilities.



Volts per hertz limiter and associated protection functions.



Stator over-voltage protection system settings.



Generator and transformer volts per hertz capability.



Time vs. field current or time vs. stator current.

NOTE:

This listing is for reference only. This standard does not require the installation or
activation of any of the above limiter or protection functions.

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Standard PRC-019-1 — Coordination of Generating Unit or Plant Capabilities, Voltage
Regulating Controls, and Protection

For this example, the Steady State Stability Limit (SSSL) is the limit to synchronous
stability in the under-excited region with fixed field current.
On a P-Q diagram using Xd as the direct axis saturated synchronous reactance of the
generator, Xs as the equivalent reactance between the generator terminals and the
“infinite bus” including the reactance of the generator step-up transformer and Vg as the
generator terminal voltage (all values in per-unit), the SSSL can be calculated as an arc
with the center on the Q axis with the magnitude of the center and radius described by the
following equations
C = V2g/2*(1/Xs-1/Xd)
R = V2g/2*(1/Xs+1/Xd)
On an R-X diagram using Xd as the direct axis saturated synchronous reactance of the
generator, and Xs as the equivalent reactance between the generator terminals and the
“infinite bus” including the reactance of the generator step-up transformer the SSSL
is an arc with the center on the X axis with the center and radius described by the
following equations:
C = (Xd-Xs)/2
R = (Xd+Xs)/2

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Standard PRC-019-1 — Coordination of Generating Unit or Plant Capabilities, Voltage Regulating Controls, and
Protection

Section G Attachment 1 – Example of Capabilities, Limiters and Protection on a P-Q Diagram at nominal voltage and
frequency

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Standard PRC-019-1 — Coordination of Generating Unit or Plant Capabilities, Voltage Regulating Controls, and
Protection

Section G Attachment 2 – Example of Capabilities, Limiters, and Protection on an R-X Diagram at nominal voltage and
frequency

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Standard PRC-019-1 — Coordination of Generating Unit or Plant Capabilities, Voltage Regulating Controls, and
Protection

Section G Attachment 3 - Example of Capabilities, Limiters, and Protection on an Inverse Time Characteristic Plot

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* FOR INFORMATIONAL PURPOSES ONLY *
Enforcement Dates: Standard PRC-019-1 — Coordination of Generating Unit or Plant Capabilities,
Voltage Regulating Controls, and Protection
United States
Standard

Requirement

PRC-019-1

All

Enforcement Date

Inactive Date

This standard has not yet been approved by the applicable regulatory authority.

Printed On: August 23, 2013, 08:02 AM