2010 04 TDM Monday 5 Miller, Hank and Taitro, Phil

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Protection Coordination

Phil Tatro – NERC Senior Performance and Analysis Engineer

Hank Miller – AEP Staff Electrical En ineer

EEI 2010 Apr Transmission, Distribution and Metering Conference

April 12, 2010



2

System Protection and Control Performance



3

The InitiativeThe Initiative

System Protection and Control Performance

Im rovement Initiative – aka SPI

Launched April 24, 2009

NERC Board recognition of the importance of

system protection to reliability Goal: Improve BES reliability

system Protection Systems through fostering

technical excellence in protection and control

system design, coordination, and practices.



4

The InitiativeThe Initiative

Elevate System Protection and ControlTask Force to Subcommittee status

• Increased emphasis on the importance of protection

• IEEE Power & Energy Society

•

• Bridge between IEEE standards and NERC systemperformance requirements (in NERC standards)

Coordinate Protection Standards Philosophies andStandards Work

• Technical basis for all protection standards changes

• Reduce discrepancies



5

SPI Targeted AreasSPI Targeted Areas

PRC Standards Technical Support

•

process

Rela Loadabilit

• Standard PRC-023 – Relay Loadability

• SPCS Technical Reference Document & SAR

Generator Frequency and Voltage Protective RelayCoordination

• ra ng o an ar - - — enera or requency

and Voltage Protective Relay Settings



6


Transmission and Generation Protection S stem

Misoperations

• SPCTF 2007 Technical Reference Document on

Protection S stem Maintenance



7


BES System Performance & Protection

Coordination with Turbine/Boiler Controls

• Next thrust of the SPI

•

• Largely uncharted area for modeling by planners• Discussions with industry experts and turbine control

manufacturers on appropriate level of modeling (detailed

modelin not a ro riate

• New control models need to be applied

• o e va a on o ac ua sys em per ormance essen a



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Power Plant and Transmission Systemro ec on oor na onThe Technical Reference Document



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A Technical Reference Document A Technical Reference Document

Protection Coordination

•

Control Subcommittee (SPCS)

• A roved b the NERC Plannin Committee on

December 8, 2009



10

BackgroundBackground

Generation – Transmission protection

protection misoperations that were causal or contributor to si nificant disturbances 2005-2009

Technical Reference Document published in

Technical bridging document between IEEE

A series of workshops and webinars are planned to

ssem na e n orma on



11

Introduction and BackgroundIntroduction and Background – –

Blackout Recommendation TR Blackout Recommendation TR--2222

SPCS’s Assi nment:

• Recommendation TR–22 - “NERC should evaluate theseprotection schemes and their settings for appropriateness

within a coherent generation area (but weakly connected to an

interconnection) or within an electrical island. Generators directly

consider the use of an impedance relay instead.”

• The SPCS adopted a 0.85 per unit voltage at the system high-

-voltage condition for an extreme system event in this document.



12

History and Concerns Driving the EffortHistory and Concerns Driving the Effort

challenges driving this effort.• ,

• Subsequent Events



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August 14, 2003 Blackout August 14, 2003 Blackout

The record of generator trips (290 units, about 52,745 MW) duringthe North American disturbance on August 14, 2003.

Included thirteen types of generation-related protection functionsthat operated to initiate generator tripping.

of those generator trips were appropriate for the Bulk ElectricSystem (BES) conditions, and which were undesired trips.

of the blackout.



14

Subsequent EventsSubsequent Events

concerns have been observed and analyzed:•

Transmission System protection

• Tri s due to auxiliar s stems

• Power Plant design concerns

contactor actuation

• - -



15

InterrelationshipsInterrelationships -- ProtectionProtection

and Controls Coordination Goalsand Controls Coordination Goals“ A reliable electric system requires: proper protection and control

coordination between power plants and transmission system.”

System

Conditions

System

Conditions

System

Conditions

Gen Protection

Trans

ProtectionPRC-001 Coordination

Gen ProtectionGen ProtectionGen Protection

Trans

Protection

Trans

Protection

Trans

ProtectionPRC-001 Coordination

Gen Controls System

ControlsGen ControlsGen ControlsGen Controls System

Controls

System

Controls

System

Controls

Turbine / Boiler Turbine / Boiler Turbine / Boiler Turbine / Boiler



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What is Coordination for Purposes of What is Coordination for Purposes of

this Technical Reference Documentthis Technical Reference Document

Coordination of generation and transmission protection

,

power plant protection and related control elements must

be set and configured to prevent unnecessarily trippinge genera or pr or o any ransm ss on pro ec on an

related control systems acting first, unless the generator

is in jeopardy by exceeding its design limits due to

operating conditions, generator system faults, or other adverse potentially damaging conditions.



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Power Plant and Transmission SystemPower Plant and Transmission System

Coordination Ob ectivesCoordination Ob ectives

The goal of this document is to explore all generating plant,

undesired trips during system disturbances or extreme stressedsystem conditions.

the transmission system.

Promote information exchange requirements between the Generator Owner, Transmission Owner, and Planning Coordinator.

Provide a technical basis to evaluate coordination betweengenerating plant and transmission system protection, with examples.

Provide a self-examination and coordination rocess that will

significantly reduce the number of undesired trips in future events,thus improving system reliability.

Provide Technical Reference support for NERC Protection andon ro an ar s.



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ScopeScope

Focus is on the reliability of the Bulk Electric System.

This Technical Reference Document is applicable to all generators,but concentrates on those generators connected at 100 kV andabove.

• Note that the Technical Reference Document was developed with afocus on synchronous generators, and discussion for some protection

functions may not be applicable to asynchronous generators.

Distributed Generation (DG) facilities connected to distributionsystems are outside the scope of this document.

Information exchange requirements between Generator Owners and

Transmission Owners to facilitate coordination between their protection schemes.



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PRC Standards SupportPRC Standards Support

Support of the Following Standards

• - – -

Purpose: To ensure that System Protection Coordination is achieved and to ensure thatreal-time operating personnel have the information needed to react to the operations of Protection Systems and Transmission Planners have Protection System information toperform planning functions.

• PRC-006 – NERC Project 2007-01: Automatic Underfrequency LoadShedding

Purpose: To establish design and documentation requirements for automaticunderfrequency load shedding (UFLS) programs to arrest declining frequency andass s recovery o requency o ow ng un er requency even s.

• PRC-023: Relay Loadability

Purpose: Protective relay settings shall not limit transmission loadability; not interferewith system operators’ ability to take remedial action to protect system reliability and; be

faults.

• PRC-024 – NERC Project 2007-09: Generator Frequency and VoltageProtective Relay Settings

Purpose: Ensure that generator frequency and voltage protective relays are set tosupport transmission system stability during voltage and frequency excursions.



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Benefits of CoordinationBenefits of Coordination

to the Generator Ownerto the Generator Owner

Continuin to enerate ener and roduce revenue

during these system events instead of unnecessarilytripping the unit.

Avoiding a unit trip and start-up as well as associated

costs.

Not placing undue burden on other generating units in

the fleet with the unnecessary loss of a given unit – both

MW and Mvar loadin .

Reduction in start/stop cycles potentially reducing

maintenance cycle frequencies.



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to the Transmission Ownerto the Transmission Owner

power transfer.

system.

e uc on o ransm ss on ne over oa s.

Reduce unnecessary breaker and other

equipment operations.

Reduce likelihood of islanded s stem conditions.



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to the Plannin Coordinatorto the Plannin Coordinator

Im roved accurac of simulated s stem

response. Increased confidence in results of lannin

studies.

Achieved b :

• Reducing the likelihood of generation tripping duringstable system swings and other recoverable system

con ons, an• Identifying conditions for which generators may trip,

consequence of such trips.



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Reliability of the Bulk Electric System andReliability of the Bulk Electric System and

Reliabilit of Power Deliver to the CustomerReliabilit of Power Deliver to the Customer

system events and associated impacts to lostproduction and power utilization.

More reliable infrastructure and power supply.



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Review of Technical Reference Table 2Review of Technical Reference Table 2

Table 2 provides an executive summary for the protection system functioncoordination described in this technical document. The three columns

• Column 1 — the protective functions that require coordination by theGenerator Owner.

• — coordination by the Transmission Owner.

• Column 3 — the system concerns the Transmission Owner and

Generator Owner must, as a minimum, jointly address in their .

Table 2 Excerpt — Device 21 Protection Coordination Data Exchange Requirements

Transmission System Protection Relays

–

21

87B

Both 21s have to coordinate,

Trip dependability,

Breaker failure time,

System swings (out‐of ‐step blocking),

87T

50BF

Protective Function Loadability for extreme

system conditions that are recoverable

System relay failure

Settings should be used for planning and system studies



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Review of Technical Reference Table 3Review of Technical Reference Table 3

Table 3 provides the detailed information required from each entity tobe exchanged for each function, such as the protection set points, timedelays and other detailed data. The three columns provide thefollowing information:

• Column 1 — the detailed data the Generator Owner must provide to theTransmission Owner

• —

Table 3 Excer t — Device 21 Data To be Provided

Generator Owner

• Column 3 — concerns that need to be addressed with the Planning Coordinator

Generator Owner Transmission Owner Planning Coordinator

Relay settings in the R‐X plane in primary ohms

at the generator terminals.

One line diagram of the transmission system up

to one bus away from the generator high‐side

bus[1].

Feedback on coordination problems found in

stability studies.

Relay timer settings.Impedances of all transmission elements

connected to

the

generator

high

‐side

bus.

None

Total clearing times for the generator breakers.Relay settings on all transmission elements

connected to the generator high‐side bus.None

Total clearing times for all transmission

‐

bus.

None

Total clearing times for breaker failure, for all

transmission elements

connected

to

the

generator high‐side bus.None



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General Data Exchange RequirementsGeneral Data Exchange Requirements – –

Generator Owner Data and InformationGenerator Owner Data and Information

The following general information must be exchanged in addition to,

• Relay scheme descriptions

• Generator off nominal frequency operating limits

• CT and VT/CCVT configurations

• Main transformer connection configuration

• Main transformer tap position(s) and impedance (positive and zerosequence) and neutral grounding impedances

• High voltage transmission line impedances (positive and zerosequence) and mutual coupled impedances (zero sequence)

• enera or mpe ances sa ura e an unsa ura e reac ances ainclude direct and quadrature axis, negative and zero sequenceimpedances and their associated time constants)

• Documentation showing the function of all protective elements listedabove



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General Data Exchange RequirementsGeneral Data Exchange Requirements – –Transmission or Distribution Owner Data and InformationTransmission or Distribution Owner Data and Information

The following general information must be exchanged in addition to,

• Relay scheme descriptions• Regional Reliability Organization’s off-nominal frequency plan

• CT and VT/CCVT configurations

• Any transformer connection configuration with transformer tap

position(s) and impedance (positive and zero sequence) and neutral

• High voltage transmission line impedances (positive and zerosequence) and mutual coupled impedances (zero sequence)

• Documentation showin the function of all rotective elements

• Results of fault study or short circuit model

• Results of stability study

-



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Document FormatDocument Format – – Seven SubSeven Sub--SectionsSections

for Each Protection Functionfor Each Protection Function

Purpose

Coordination of Generator and Transmission System

• Faults

• Loadability

• Other Conditions, Where Applicable

Considerations and Issues

Setting Validation for the Coordination• Test Procedure for Validation

• Setting Considerations

Examples

• Proper Coordination• Improper Coordination

Summary of Detailed Data Required for Coordination of the ProtectionFunction

Table of Data and Information that Must be Exchanged



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Functions Covered in theFunctions Covered in the

Technical Reference DocumentTechnical Reference Document

Phase Distance Protection (Function 21)

Overexcitation or V/Hz (Function 24)

Undervoltage Protection (Function 27)

•

• High Side Protection Applied at Point of Common Coupling

• Generating Plant Auxiliary Power Supply Systems Reverse Power Protection (Function 32)

Loss-of-Field Protection (LOF) (Function 40)

46)

Inadvertent Energizing Protection (Function 50/27)



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Functions Covered in theFunctions Covered in the

Technical Reference DocumentTechnical Reference Document

(Function 51TG)

Voltage-Controlled or -Restrained Overcurrent Relay (Function 51V)

Stator Ground Relay (Function 59GN/64G)

Out-of-Step or Loss-of-Synchronism Relay (Function 78)

Over and Underfrequency Relay (Function 81)

Transformer Differential Relay (Function 87T), Generator Differential Relay(Function 87G) Protection and Overall Differential Protection (Function 87U)



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Sharing the InformationSharing the Information

-

Standing Committee meetings to inform theindustry on the contents of the Technical

Reference Document

A series of Webinars are lanned for Ma -June

• Seven weekly sessions – a different topic each week

oor na ng reg ona presen a ons These future sessions will be announced soon



32

uestion & Answer

Contact:

Phil Tatro, System Analysisand Reliability Initiatives

[email protected]

. .

2010 04 TDM Monday 5 Miller, Hank and Taitro, Phil

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