ICS27.100

P60

RecordNumber：J1954-2015

P

-

TechnicalCodefortheDesignofAuxiliary

PowerSystemofFossil-firedPowerPlant

火力發(fā)電廠廠用電設(shè)計技術(shù)規(guī)程

IssuedonOctober15，2014ImplementedonMarch1，2015

IssuedbytheNationalEnergyAdministration

ELECTRICPOWERINDUSTRYSTANDARD

OFTHEPEOPLESREPUBLICOFCHINA

TechnicalCodefortheDesinofAuxiliar

gy

PowerSstemofFossil-firedPowerPlant

y

/

DLT5153-2014

/

RelaceDLT5153-2002

p

：

ChiefDevelopmentDepartmentElectricPowerPlanningand

EnineerinInstitute

gg

：

ApprovalDepartmentNationalEnergyAdministration

：，

ImlementationDateMarch12015

p

ChinaPlanninPress

g

Beiin2022

jgChineseeditionfirstublishedinthePeolesReublicofChinain2014

ppp

EnglisheditionfirstpublishedinthePeoplesRepublicofChinain2022

byChinaPlanningPress

rd

，，

3FloorCTowerGuohongBuilding

，，

No.A11Muxidi-BeiliXichengDistrict

，

Beiin100038

jg

，

PrintedinChinabBeiinhouchenzeminPrintinTechnoloCo.Ltd

yjgggggy

?2014byNationalEnergyAdministration

Allrihtsreserved.Noartofthisublicationmabereroducedor

gppyp

，，，，

transmittedinanyformorbyanymeansgraphicelectronicormechanical

，，

includingphotocopyingrecordingoranyinformationstorageand

，

retrievalsstemswithoutwrittenermissionoftheublisher.

ypp

，

Thisbookissoldsubjecttotheconditionthatitshallnotbywayof

，，，

tradeorotherwisebelentresoldhiredoutorotherwisecirculated

withouttheublishersriorconsentinanformofblindinorcover

ppyg

otherthanthatinwhichthisispublishedandwithoutasimilarcondition

includinthisconditionbeinimosedonthesubseuenturchaser.

ggpqp

ISBN978-7-5182-1431-0Introduction

，

ThisEnglishversionwhosetranslationwasorganizedby

ChinaElectricPowerPlanninandEnineerinInstitute.

ggg

AuthorizedbNationalEnerAdministrationincomliance

ygyp

，

withrelevantproceduresandstipulationsisoneofChinas

enerindustrstandardsinEnlishseries.ThisEnlish

gyygg

versionwasublishedbNationalEnerAdministrationin

pygy

〔〕，

Announcement2021No.5datedNovember16th2021.

TheEnlishversionwastranslatedfromtheChinese

g

/

StandardDLT5153-2014TechnicalCodeortheDesino

fgf

AuxiliaryPowerSystemofFossil-firedPowerPlantpublished

byChinaPlanningPress.

ThecorihtisownedbNationalEnerAdministration.

pygygy

，

Intheeventofandiscreancintherocessofimlementation

ypypp

theChineseversionshallprevail.

Manthankswouldotothestafffromrelevantstandard

yg

develomentoranizationsandthosewhohaverovided

pgp

generousassistanceinthetranslationandreviewprocess.

，

ForfurtherimrovementoftheEnlishversionall

pg

commentsandsuestionsarewelcomeandshouldbe

gg

addressedtoChinaElectricPowerPlanningandEngineering

，，，

Institute.No.65AnderoadXichengDistrictBeijing100120

：

China.Websitewww.e.

pp

··

1：

Translatinoranizations

gg

，

EastChinaElectricPowerDesignInstituteCo.Ltd.of

，

ChinaPowerEnineerinConsultinGrouElectricPower

gggp

，

PlanninandEnineerinAssociationSUNTHERIndustr

gggy

，

DataBenchmarkingCo.Ltd.

：

Translatinstaffs

g

，

EastChinaElectricPowerDesignInstituteCo.Ltd.of

：，

ChinaPowerEnineerinConsultinGrouGUYuelinXU

gggpg

，，，，，

JianhaoLIXizhiWANGJianfanHANXiaohuiHEPin

gg

MIAOZhenkun

：

ElectricPowerPlanninandEnineerinAssociationSU

ggg

，

HonghongLIMengqiao

，：

SUNTHERIndustrDataBenchmarkinCo.Ltd.LI

yg

，，

JunLIUJianxiaLIUYuin

qg

：

Reviewpanelmembers

WEIXiananNortheastElectricPowerDesin

g

，

InstituteCo.Ltd.ofChinaPower

EngineeringConsultingGroup

LOUHuiboElectricPowerPlanninand

g

，

EngineeringInstituteCo.Ltd.

YAOWenCentralSouthernChinaElectric

，

PowerDesignInstituteCo.Ltd.of

ChinaPowerEngineeringConsulting

Grou

p

ZHANGHuanchangNorthwestElectricPowerDesign

，

InstituteCo.Ltd.ofChinaPower

EnineerinConsultinGrou

gggp

HUZhenxingSouthwestElectricPowerDesign

··

2，

InstituteCo.Ltd.ofChinaPower

EngineeringConsultingGroup

LIHeNorthChinaPowerEnineerin

gg

，

Co.Ltd.ofChinaPower

EngineeringConsultingGroup

WANGLiStateNuclearElectricPower

，

PlanninDesinandResearch

gg

，

InstituteCo.Ltd.

WANGShaoyongGuangdongElectricPowerDesign

，

InstituteCo.Ltd.

ZHANGNonCEECZheianElectricPower

gjg

，

DesignInstituteCo.Ltd.

··

3翻譯出版說明

本譯本為國家能源局委托電力規(guī)劃設(shè)計總院按照有關(guān)程序

，。

和規(guī)定統(tǒng)一組織翻譯的能源行業(yè)標準英文版系列譯本之一

年月日，國家能源局以年第號公告予以公布。

2021111620215

本譯本是根據(jù)中國計劃出版社出版的《火力發(fā)電廠廠用電設(shè)

計技術(shù)規(guī)程》/翻譯的，著作權(quán)歸國家能源局所

DLT5153-2014

。，，。

有在使用過程中如出現(xiàn)異議以中文版為準

，

本譯本在翻譯和審核過程中本標準編制單位及編制組有關(guān)

成員給予了積極協(xié)助。

為不斷提高本譯本的質(zhì)量，歡迎使用者提出意見和建議，并

反饋給電力規(guī)劃設(shè)計總院。

地址：北京市西城區(qū)安德路號

65

：

郵編

100120

：

網(wǎng)址

www.e

pp

本譯本翻譯單位：

中國電力工程顧問集團華東電力設(shè)計院有限公司、中國電力

規(guī)劃設(shè)計協(xié)會、北京雙澤維度信息技術(shù)有限公司

本譯本翻譯人員：

：、

中國電力工程顧問集團華東電力設(shè)計院有限公司顧越嶺

徐劍浩、李錫芝、王建芳、韓曉輝、何平、繆震昆

中國電力規(guī)劃設(shè)計協(xié)會：蘇紅紅、李夢喬

北京雙澤維度信息技術(shù)有限公司：李俊、劉建霞、劉玉晴

本譯本審核人員：

魏顯安東北電力設(shè)計院有限公司

··

1婁慧波電力規(guī)劃設(shè)計總院

姚雯中南電力設(shè)計院有限公司

張歡暢西北電力設(shè)計院有限公司

胡振興西南電力設(shè)計院有限公司

李和華北電力設(shè)計院有限公司

王麗國核電力規(guī)劃設(shè)計研究院有限公司

汪少勇廣東省電力設(shè)計研究院有限公司

張農(nóng)浙江省電力設(shè)計院有限公司

··

2NationalEnerAdministration

gy

Announcement

〔〕

2014No.11

Accordintothe＂NoticeoNationalEnerAdministration

gfgy

othePeolesReublicoChinaonPrintinandDistributin

fppfgg

（

RegulationsofEnergyIndustryStandardizationTrial

）（〔〕），

VersionandImlementinRules＂GNJKJ2009No.52

pg

theNationalEnerAdministrationhasaroved330industr

gyppy

standardssuchasCarbonSteelandLowAlloySteelfor

：

PressurizedWaterReactorNuclearPowerPlants-Part17

，

Push-moldedElbowsorMainSteamSstemafterreview

fy

（），

consistingof71energyindustrystandardsNB122electric

（），

powerindustrystandardsDLand137petroleumandnatural

（）

asindustrstandardsSY.Theareherebreleased.

gyyy

：

AendixListofIndustrStandards

ppy

NationalEnergyAdministration

，

October152014

··

1：

Appendix

ListofIndustrStandards

y

StandardStandardSuersededReferenceArovalImlementation

pppp

No.

No.NameStandardStandardDateDate

……

TechnicalCode

fortheDesign

//，，

DLTofAuxiliaryDLTOctober15March1

172

5153-2014PowerSstem5153-200220142015

y

ofFossil-fired

PowerPlant

……

··

2Foreword

AccordingtotherequirementsofNoticeonIssuanceo

f

PlanorDevelomentoElectricPowerIndustrStandards

fpfy

in2008issuedbytheGeneralOfficeofNationalDevelopment

（〔〕），

andReformCommissionFGBGY2008No.1242the

/

draftingteamhasrevisedDLT5153-2002TechnicalCode

ortheDesinoAuxiliarPowerSstemoFossil-ired

fgfyyff

，

PowerPlantbasedonwideinvestiationsandstudies

g

，

summarizationofexperienceandextensiveconsultations.

，

Thiscodecomrises9chatersand17aendices

pppp

maintainingtheframeworkofthe2002edition.Therevisions

：

mademainlincludethefollowin

yg

/

1.FororiinalarticlesinDLT5153-2002Technical

g

CodefortheDesignofAuxiliaryPowerSystemofFossil-

iredPowerPlantwhichrovideanincomleteictureofthe

fppp

，

designofauxiliarypowersystemfor600MWaboveunits

，

eseciallfor1000MWunitssucharticleshavebeen

py

，

modifiedsulementedandimrovedbasedontheexerience

pppp

gainedinrecentyearsinChinafromdesignofnearlyone

hundredofunitsratedat1000MWandnearlfiftofthem

yy

alreadyputintooperation.

2.ThenewsectionstitledAuxiliarPowerLoad

y

，

ClassificationAuxiliarPowerEnerQualitandHarmonic

ygyy

Suppressingareincludedtodealwiththenewsituationsfaced

··

1bthedesinofauxiliarowersstem.

ygypy

3.Thekeyaspectsinthedesignofauxiliarypower

，

sstemhavebeenudatedandsulementedincludin

ypppg

，

auxiliarowerloadclassificationauxiliarowersstem

ypypy

，

voltagelevelearthingmethodsofneutralpointofhighand

，

low-voltaeauxiliarowersstemwirinmodesofMV

gypyg

，，

auxiliarypowersystemstatisticsofauxiliarypowerloadsand

confiurationandconnectionofhih-voltaestandbower

gggyp

，

sulivinmorenormativeuidanceforthedesinof

ppygggg

auxiliarypowersystemoflarge-capacityfossil-firedpower

units.

4.Newarticlesregardingdeterminationofthecalculated

loadsoftwoLVtransformersservinasstandbforeach

gy

otherhavebeenaddedinthesectionStatisticsofAuxiliar

y

PowerLoadstooptimizethecapacityconfigurationofunit

（）

auxiliartransformerUAT.Theconfiurationandconnectionof

yg

HVstandbypowersupplyandthevoltageregulationmodesof

/

UATandHVstartupstandbytransformerincaseswherethe

eneratorcircuitbreakerisinstalledaresecifiedinamoreflexible

gp

way.Thearrangementrequirementsforauxiliaryswitchgear

includethoseforcurrentlcommonlusedmiddle-mountedte

yyyp

switchgearcabinet.

5.Basedontheoriginalcalculationformulafordesigning

，

auxiliarowerconsumtionrateAendixAresentsan

yppppp

estimationmethodwhichmakesstatisticsoftheauxiliary

，

consumtionratebweihtederiodsoftimetakininto

pygpg

accounttheactualoerationconditionsoftheunits.Aendix

ppp

Bupdatesthenamesofloadsofboilerandsteamturbine

··

2discilines.AendixMandAendixNudateshort-circuit

pppppp

currenttablesandcurvesforLVauxiliarypowersystemand

·

includethealicationof2500kVAdr-tetransformers.

ppyyp

/

ThiscodewillsuersedeDLT5153-2002Technical

p

CodeortheDesinoAuxiliarPowerSstemoFossil-

fgfyyf

iredPowerPlantasoftheimlementationdate.

fp

ThiscodeisadministeredbytheNationalEnergy

，

AdministrationofthePeolesReublicofChinaroosedb

ppppy

，

theElectricPowerPlanninandEnineerinInstituteand

ggg

routinelymanagedbythePowerGenerationDesign

StandardizationTechnicalCommittee.TheEastChinaElectric

PowerDesignInstituteofChinaPowerEngineeringConsulting

GrouCororationisresonsiblefortheinterretationofsecific

ppppp

technicalissues.Ancommentsandsuestionsraiseddurin

yggg

implementationofthiscodearetobereferredtotheElectric

PowerPlanninandEnineerinInstituteatNO.65Ande

ggg

，，，，

RoadXichengDistrictBeijingP.R.China100120.

，

Chiefdevelopmentorganizationchiefdraftingstaffsand

：

chiefreviewinstaffsofthiscodeareasfollows

g

：

Chiefdevelopmentorganization

EastChinaElectricPowerDesinInstituteof

g

ChinaPowerEngineeringConsultingGroup

Corporation

：

Chiefdraftinstaffs

g

GUYuelingXUJianhaoLIXizhiWANGJianfang

HANXiaohuiHEPinMIAOZhenkun

g

：

Chiefreviewinstaffs

g

SUNWanglinWANGYuyingHUANGShengrui

··

3ZHANGJunzhenLIHeWANGLi

WANGShaoyongZHANGNongZHOUJian

ZHANGZhaoanDAIQiuhuaWANGJion

yggg

YAOShaohonDUANZonzhouZHANGYuin

ggpg

ZHUMinZHANGYousheZHOUQingyuan

BAIWenguangJIMingHUZhenxing

··

4Contents

…………………（）

1GeneralProvisions1

………………（）

2Terms3

（）

……

3AuxiliarPowerSstemWirin4

yyg

……（）

3.1LoadClassification4

（）

…

3.2AuxiliarPowerSstemVoltaeClass6

yyg

……………（）

3.3ElectricalEnergyQuality8

3.4EarthingMethodsofNeutralPointofAuxiliaryPower

………………（）

Sstem9

y

………………（）

3.5WiringModesofAuxiliaryPowerBusbars10

……（）

3.6AuxiliarOeratinPowerSul12

ypgppy

（）

/…

3.7AuxiliaryStandbyandStartupStandbyPowerSupply14

…………（）

3.8ACEmerencPowerSul20

gyppy

（）

…………

3.9UninterrutiblePowerSul20

pppy

…………（）

3.10WiringandSupplyModeofAuxiliaryLoads21

（）

………………

3.11LVMaintenancePowerSulNetwork30

ppy

/

4SelectionofAuxiliaryTransformerReactorand

（）

…………

CheckofMotorVoltaedurinStartu32

ggp

……………（）

4.1LoadCapacityCalculation32

（）

/…………

4.2TransformerReactorSizin33

g

………………（）

4.3VoltageRegulationandRegulatingModes35

（）

………

4.4Short-circuitImedanceSelection36

p

4.5CheckofVoltaeofAuxiliarBusesandMotorsdurin

gyg

………（）

NormalStarting37

··

14.6CheckofVoltaeofAuxiliarBusbarsdurinGroued

gygp

（）

…………………

MotorsSelf-startin38

g

………………（）

4.7HarmonicsRestraining39

………………（）

5Motors42

（）

………

5.1TypeSelection42

………………（）

5.2RatingofVoltageandCheckofCapacity43

6Short-circuitCurrentCalculationandElectrical

………………（）

EquipmentandConductorSelection46

6.1Short-circuitCurrentCalculationinMVAuxiliary

………（）

PowerSystem46

……（）

6.2MVElectricalEuimentSelection48

qp

6.3Short-circuitCurrentCalculationinLVAuxiliar

y

（）

………

PowerSstem49

y

……（）

6.4LVElectricalEquipmentSelection50

…（）

6.5LVElectricalEuimentCoordination52

qp

（）

…

7ArranementofAuxiliarElectricalEuiment56

gyqp

………………（）

7.1AuxiliaryTransformer56

（）

…………………

7.2AuxiliarSwitchear57

yg

……………（）

7.3RequirementsonBuildingsandVentilation62

8RelaProtectionDevicesofAuxiliarPower

yy

（）

………………

Systems65

…………………（）

8.1GeneralRequirements65

8.2Single-phaseEarthingFaultProtectioninAuxiliary

………（）

PowerSstem67

y

（）

……………

8.3ProtectionforWorkinandBackuReactor71

gp

………………（）

8.4ProtectionforUnitAuxiliaryTransformer72

（）

………………

8.5ProtectionforLVAuxiliarTransformer77

y

……（）

8.6ProtectionforMVAuxiliaryMotor81

··

2……（）

8.7ProtectionforLVAuxiliarMotors84

y

……（）

8.8ProtectionforAuxiliaryFeeder-line86

（）

………

8.9ProtectionforDieselGenerator89

，，

9ControlSignalingInstrumentationandAutomatic

（）

………………

DevicesofAuxiliarPowerSstem92

yy

………（）

9.1ControlandSignalingofAuxiliaryPowerSystem92

（）

………

9.2InstrumentationofAuxiliarElectricalEuiment95

yqp

…………（）

9.3AutomaticDevicesofAuxiliarPowerSstem96

yy

，，

9.4ControlSinalinInstrumentationandAutomaticDevices

gg

…………………（）

ofDieselGenerator99

AendixADesinAuxiliarPowerConsumtion

ppgyp

…………（）

RateEstimation101

（）

……

AendixBLoadCharacteristicforReference107

pp

AendixCSelectionofNeutralPointEarthinDevice

ppg

（）

………

inMVAuxiliarPowerSstem156

yy

………（）

AendixDSelectionofDieselGeneratorSet160

pp

AppendixELocationandQuantityofMaintenance

………………（）

PowerDistributionBoxes165

………………（）

AppendixFLoadCapacityCalculation167

（）

…………

AendixGVoltae-reulationCalculation171

ppgg

AppendixHVoltageCalculationduringNormal

（）

………

StartinofMotor175

g

AppendixJVoltageCalculationduringSelf-starting

（）

………

ofGrouedMotors177

p

AendixKTemerature-riseCalculationofMotor

ppp

（）

…………

duringStarting180

AendixLPracticalCalculationofShort-circuitCurrent

pp

………（）

inMVAuxiliaryPowerSystem186

··

3AendixMPracticalCalculationofShort-circuit

pp

………（）

Currentin380VPowerCenters196

AendixNCalculationCurveofShort-circuitCurrent

pp

（）

…

in380VPowerSstem200

y

AppendixPLVFuseandCircuitBreaker

…………………（）

Selection284

AendixQ380VLVElectricalEuiment

ppqp

………（）

CombinationForm288

AppendixRCalculationofContinuousOperating

（）

………………

Currentin380VCircuit292

AendixSInstrumentsofAuxiliarElectrical

ppy

………………（）

Equipment294

（）

…

ExlanationofWordininthisCode297

pg

………………（）

ListofQuotedStandards298

··

41GeneralProvisions

1.0.1ThiscodeisdevelopedtoregulatethedesignofAC

（

auxiliarowersstemoffossil-firedowerlantshereinafter

ypypp

）

referredtoastheauxiliarypowersystemsuchthattheyare

，，

safeandreliabletechnicalladvancedandeconomicall

yy

viable.

1.0.2Thedesinofauxiliarowersstemshallcoml

gypypy

withthenationaltechnicalandeconomicoliciesinChinaand

p

ensurethenormaloperationofpowerplantsandthesafetyof

maintenanceersonnelandmaoreuiment.

pjqp

1.0.3Thiscodeisapplicabletothedesignofnewly-builtor

exandedfossil-firedowerlantsrovidedwithcondensin

ppppg

steamturbineeneratorunitswithacaacitof125MWor

gpy

aboveaswellasnewly-builtthermalpowerplantsinstalled

withheatsulunitswithacaacitof50MWorabove.

ppypy

1.0.4Thedesignofauxiliarypowersystemshalltakeinto

considerationthedevelomentlanandstaedconstructionofthe

ppg

，

entireowerlantsoastoensurethatitissafeandreliable

pp

economicallyviableandinlinewiththenationalsituationsofChina.

Newtechnoloiesandeuimentthathavebeensubectedto

gqpj

operationaltestandpassedtheappraisalshallbeactivelyand

rudentlaliedinthedesin.

pyppg

1.0.5Whentherearetwoormoreenerationunitswitha

g

，

capacityof200MWorabovetheauxiliarypowersystemsof

··

1theunitsshouldbeketindeendentofeachotherandthe

pp

，

relevancebetweenunitsshallbereducedthusimprovingthe

safetandreliabilitofunitoeration.

yyp

，

1.0.6Inadditiontothiscodethedesinofauxiliarowersstem

gypy

shallalsocomplywithrelevantcurrentnationalstandardsofChina.

··

22Terms

2.0.1Designauxiliarypowerconsumptionrate

Thedesinauxiliarowerconsumtionratemeanstheratio

gypp

betweenthewhole-earauxiliarowerconsumtionreuiredbthe

yyppqy

（）

unitsturbinesandboilerstogeneratepowerandsupplyheatand

theowerenerationandheatsulcontributedbthesameunits

pgppyy

resectiveldurinthesameeriodoftime.Itisusedtomeasureand

pygp

assessthepowerconsumptionbytheauxiliaryequipmentequipped

fortheentireowerenerationandheatsulrocessinthedesin

pgppypg

hase.

p

Thedesignauxiliarypowerconsumptionratemaybeestimated

usingthemethodsgiveninAppendixA.

··

33AuxiliarPowerSstemWirin

yyg

3.1LoadClassification

3.1.1Theauxiliarloadsinfossil-firedowerlantsmabe

yppy

classifiedintoClass0loadsandNon-class0loadsbasedontheir

imortancetothesafetofersonnelandeuiment.The

pypqp

imortanceofauxiliarloadsisdictatedbthemechanicalsstem

pyyy

，，

theybelongto.Class0loadsarethosewhichoncede-energized

willdirectlosedanertothesafetofersonnelormaor

ypgypj

equipment.Allotherauxiliaryloadsthanclass0loadsmaybe

reardedasNon-class0loads.Theclassificationandcharacteristics

g

ofusualauxiliaryloadsinfossil-firedpowerplantsshouldbe

determinedinaccordancewiththerelevantreuirementsin

q

AendixB.

pp

3.1.2Class0loadsshallbefurtherclassifiedasfollows

basedontheirimortancelevelsandtheirdemandsforower

pp

：

supplyincompliancewiththeprinciplesbelow

，

1Class0Ⅰloadswhichshallbecontinuouslowered

yp

（）

bACuninterrutibleowersulUPSdurinboththe

yppppyg

（）

operationandshutdownincludingemergencyshutdownprocess

，

ofunitsandeveninanextendederiodaftershutdown.Class0Ⅰ

p

；

loadsarealsoreferredtoasACuninterruptedlypoweredloads

，

2Class0Ⅱloadswhichshallbecontinuouslowered

yp

bDCowersulinthecaseofowerfailureinthewhole

ypppyp

plantorfailureofauxiliarypoweroftheunitssoastoensure

··

4safeshutdownofunitsortorotectthehumanbodaainst

pyg

hazards.Class0ⅡloadsarealsoreferredtoasDCemergency

；

loads

，

3Class0Ⅲloadswhichshallbecontinuouslowered

yp

byACemergencypowersupplyinthecaseofpowerfailurein

thewholelantorfailureofauxiliaroweroftheunitssoas

pyp

toensuresafeshutdownofunitsortoprotectthehumanbody

aainsthazards.Class0ⅢloadsarealsoreferredtoasAC

g

emerencloads.

gy

3.1.3Non-class0loadsshallbefurtherclassifiedbasedon

theirimortancelevelsinowerroductionrocessaccordin

ppppg

：

tothefollowingprinciples

，，，

1ClassⅠloadswhichifde-enerizedforashorttime

g

，

macomromisethenormalservicelifeofeuiment

ypqp

interruptnormalproductionorcausesignificantreductionof

；

owereneration

pg

，

2ClassⅡloadswhichmaytolerateshort-timepowerfailure

butmaycompromisethenormalservicelifeofequipmentorhave

adverseeffectsonthenormalroductionifde-enerizedforan

pg

；

extendedperiod

，

3ClassⅢloadswhichhavenodirecteffectsonroduction

p

inthecaseofpowerfailureforalongtime.

3.1.4Loadsirrelevanttotheproductionofpowerplantsshould

notbeconnectedtotheauxiliarowersstems.Asmallnumber

ypy

/，

ofloadsinauxiliarybuildingsstructuressuchasloadsin

，

administrationbuildinsanddormitoriesofattendantsmabe

gy

connectedtotheMVauxiliarowersstemthrouhadedicated

ypyg

LVauxiliarytransformer.

··

53.2AuxiliarPowerSstemVoltaeClass

yyg

3.2.1Thevoltaeofauxiliarowersstemmabedetermined

gypyy

，

asperTable3.2.1andmaybeclassifiedintothefollowingthree

：

types

，

1Sstemnominalvoltaewhichisaivenvalueusedto

ygg

；

indicateoridentifthesstemvoltae

yyg

，

2Sstemoerationvoltaewhichisthevoltaevalueof

ypgg

thesstemundernormaloerationconditions.Forauxiliar

ypy

，

owersstemthesstemoerationvoltaeis1.05timesthe

pyypg

；

systemnominalvoltage

，

3Systemmaximumvoltagewhichisthemaximumvoltage

valueofthesystemoccurringatanytimeandatanypointunder

normaloperationconditions.

Table3.2.1Voltaeofauxiliarowersstemandcorresondinreferencevalues

gypypg

（）

No.VoltaeofauxiliarowersstemReferencevalueV

gypy

，/，，，

1Sstemnominalvoltae3803802203000600010000

yg

，/，，，

2Sstemoerationvoltae4004002303150630010500

ypg

，，

3Sstemmaximumvoltae3600720012000

yg

3.2.2Thevoltaeofauxiliarowereuimentmabe

gypqpy

：

classifiedintothefollowintwotes

gyp

，

1Ratedvoltageofswitchingequipmentwhichisthe

voltagedeterminedbytheequipmentmanufacturertospecify

，

theratedworkingconditionofrelevantcomponentsdevicesor

，

equipment.For3kVandaboveelectricalequipmenttherated

voltageequalstothemaximumvoltageofthesystemtowhich

；

itisconnected

··

6，

2Maximumvoltaeofswitchineuimentwhichis

ggqp

themaximumvalueof＂systemmaximumvoltage＂thatmaybe

aliedontheelectricaleuiment.Themaximumvoltaeof

ppqpg

euimentrefersonltothesstemnominalvoltaeabove

qpyyg

1000V.

3.2.3MVauxiliarowersstemsinfossil-firedower

ypyp

，

plantsmayadoptnominalvoltagelevelsof3kV6kVand

10kV.ThevoltaelevelofMVauxiliarowersstemsshall

gypy

：

beselectedaccordintothefollowinrinciles

ggpp

1ForMVauxiliarypowersystemwiththesamewiring

，

confiurationthevoltaelevelwhichallowstheMVauxiliar

ggy

powerbusbarstohavealowershort-circuitcurrentshouldbe

selectedsothatswitchearswithlowershort-circuitratin

gg

；

mabealied

ypp

2ForMVauxiliarypowersystemwiththesamewiring

confiurationandthesameshort-circuitleveloftheMVauxiliar

gy

，

powerbusbarsalowervoltagelevelshouldbeselectedsothat

auxiliarypowerequipmentwithlowerinsulationrequirementscan

bealied.

pp

，

3.2.4Basedonthedifferentunitcapacitiesthevoltagelevelof

MVauxiliarowersstemshallbeselectedaccordintothe

ypyg

：

followingprinciples

，

1Forunitswithacapacityclassof50MWto60MW3kVor

10kVmabeselectedincaseofeneratorvoltaeat10.5kVand

ygg

；

6kVincaseofgeneratorvoltageat6.3kV

，

2Forunitswithacaacitclassof125MWto300MW6kV

py

（）；

one-levelshouldbeselected

，

3Forunitswithacapacityclassof600MWandabove6kV

··

7（），（），/（），

onelevelor10kVonelevelor10kV6kVtwolevelsor

/（）

10kV3kVtwolevelsmaybeselecteddependinguponthespecific

conditionsoftheroects.

pj

3.2.5TheLVauxiliarowersstemoffossil-firedower

ypyp

/

plantsmayuse380Vor380V220Vasitsnominalvoltage.For

，

unitswithacaacitclassof200MWandabovetheLVauxiliar

pyy

powersysteminthemainpowerbuildingshouldbeconfiguredin

suchamannerthattheowersstemandthelihtinsstemare

pyggy

oweredsearatel.Theowersstemshouldbesuliedata

ppypypp

/

voltagelevelof380Vor380220V.

3.3ElectricalEnerualit

gyQy

3.3.1Theelectricalenerualitoftheauxiliarowersstem

gyqyypy

infossil-firedowerlantsincludestheualitofvoltaeand

ppqyg

，：

frequencyandshouldmeetthefollowingrequirements

，

1UndernormaloerationthevariationraneofAC

pg

busbarvoltageshouldbewithin95%to105%ofthenominal

；

voltage

，

2UndernormaloerationthevariationraneofAC

pg

busbarfrequencyshouldnotexceed49.5Hzto50.5Hzwhen

，

theauxiliarowerbusbarissuliedbtheowerridand

ypppypg

shouldnotexceed49Hzto51Hzwhensuppliedbythein-plant

；

ACpowersupply

，

3Undernormaloerationthecontentofeachorderof

p

，

harmonicvoltageinACbusbarshouldnotbelargerthan3%

andthetotalharmonicsdistortionofvoltaeshouldnotbe

g

larerthan5%for380Vauxiliarowersstemand4%for

gypy

6kVand10kVauxiliarypowersystem.

··

83.4EarthinMethodsofNeutralPointofAuxiliarPowerSstem

gyy

3.4.1TheMVauxiliarowersstemmahavetheneutral

ypyy

ointunroundedorroundedviaresistance.Theearthinmethods

pggg

ofneutralointsandtheobectsoeratedbtherotectionsshall

pjpyp

bedeterminedinaccordancewithTable3.4.1.

Table3.4.1Determinationofearthinmethodsofneutralointsand

gp

theobectsoeratedbtherotectionsinMVauxiliarowersstem

jpypypy

Earthingmethodsofneutralpoints

EarthincaacitivecurrentI

gpc

andtheobjectsoperatedbyprotections

，

Groundedviahighresistance

，

Ungroundedtheprotection

1

I≤7Atherotectionoerates

cpp

operatestocausesignaling

tocausesignaling

，

Groundedvialowresistance

，

Unroundedtherotection

gp

2

7A＜Ic≤10Atheprotectionoperates

operatestocausesignaling

tocausetriin

ppg

，

Groundedvialowresistance

3

Ic＞10A

theprotectionoperatestocausetripping

：

Notes1WhentheearthingcapacitivecurrentinMVauxiliarypowersystemis

，，

7Aorlessitsneutralmabeunroundedormaberoundedthrouh

ygygg

hihresistancewhichshallberoerlselectedsuchthatthetotal

gppy

currentincaseofsinglephase-to-earthfaultisbelow10A.The

protectionoperatestocausealarmsignaling.

2WhentheearthincaacitivecurrentinMVauxiliarowersstemis

gpypy

，，

larerthan7Aanduto10Aitsneutralmabeunroundedormabe

gpygy

，

roundedthrouhlowresistance.Inthiscasethecorresondintotal

ggpg

currentincaseofsinglephase-to-earthfaultshallbedeterminedin

accordancewithNote1orNote3respectively.

3WhentheearthincaacitivecurrentofMVauxiliarowersstemis

gpypy

，

above10Aitsneutralshouldberoundedthrouhlowresistance.Such

gg

，

resistanceshallbeselectedsuchthatincaseofasinglephase-to-earth

，，

faulttheresistivecurrentisnotsmallerthancapacitivecurrentandthe

resultingtotalcurrentshallcausetheprotectiondevicestooperate

accuratelandsensitiveltocausetriin.

yyppg

··

93.4.2TheneutralointearthineuimentofMVauxiliar

pgqpy

powersystemmaybeselectedusingthecalculationmethods

iveninAendixC.

gpp

3.4.3TheearthinmethodsofneutralointsofLVauxiliar

gpy

powersystemshallcomplywiththerelevantrequirementsin

currentnationalstandardGB50660CodeorDesinoFossil

fgf

FiredPowerPlant.

3.5WirinModesofAuxiliarPowerBusbars

gy

3.5.1Single-busbarwiringshallbeappliedforMVauxiliary

busbars.ThenumberofMVauxiliarowerbusbarsectionsof

yp

eachunitshallbedeterminedtakingintoaccounttheratedcurrent

，

andshort-circuitcurrentlevelofbusbarsthevoltaedrolevel

gp

，

causedbthestartinofmotorandthereuirementsforvoltae

ygqg

regulationandtherequirementsthatdualsetsofauxiliary

euimentshallbesuliedbdifferentbusbarsections.TheMV

qpppy

auxiliarypowerbusbarsshallbeconfiguredinaccordancewiththe

：

followingprinciples

，

1Forunitswithacaacitof50MWto60MWeachunit

py

maybeprovidedwithonesectionofMVauxiliarypowerbusbar.

Whenthenumberofturbinesisnotthesamewiththatofthe

/，

boilersandtheboilercapacityisbelow400theachboilermaybe

；

providedwithonesectionofMVauxiliarypowerbusbar

，

2Forunitswithacaacitof125MWto300MWeach

py

unitshallbeprovidedwithtwosectionsofbusbarsforeach

，

voltaelevelofMVauxiliarowerandmotorsofdualsetsof

gyp

auxiliareuimentshallbesearatelconnectedtothetwo

yqppy

；

busbarsections

··

10，

3Forunitswithacaacitof600MWeachunitshallbe

py

，

providedwithatleasttwosectionsofbusbarsandmotorsof

dualsetsofauxiliareuimentshallbesearatelconnected

yqppy

；

tothetwobussections

，

4Forunitswithacapacityof1000MWoraboveeach

unitshallberovidedwithatleasttwosectionsofbusbarsfor

p

，

eachvoltagelevelofMVauxiliarypowerandmotorsofdual

setsofauxiliareuimentshallbesearatelconnectedtothe

yqppy

twobussections.

3.5.2Ifboththequantityandcapacityofcommonloads

withinthelantareaarelareandthecombinationofower

pgp

，

supplymodesisreasonablecommonMVbusbarsections

，

shouldberovidedandthenumberofcommonMVbusbar

p

sectionsacrosstheentirelantareashallnotbelessthantwo.

p

SuchcommonsectionsshallbepoweredfromtheMVauxiliary

，

owerbusbarsoftwounitsorfromsearateMVauxiliar

ppy

，

powertransformerssoastoensurethereliabilityofpower

supplyforimportantcommonloads.

3.5.3Sinle-busbarwirinmodeshallbealiedforLV

ggpp

auxiliarypowerbusbars.TheLVauxiliarypowerbusbarsshallbe

：

confiuredinaccordancewiththefollowinrinciles

ggpp

，

1Forunitswithacapacityof50MWto60MWwhenthe

LVauxiliarypowerbusbarsareconnectedwithClassIloadsof

，

turbinesandboilerssuchbusbarsshouldbesectionalizedbthe

y

，

boilersorturbinescorrespondingtothesectionalizationofMV

；

auxiliarowerbusbars

yp

，

2Forunitswithacaacitof125MWto200MWeach

py

unitmaybepoweredbytwosectionsofbusbarsandthe

··

11motorsofdualsetsofauxiliareuimentaresearatel

yqppy

connectedtotwosectionsofbusbarswhichmaybepoweredby

；

sinletransformer

g

，

3Forunitswithacaacitof300MWoraboveeachunit

py

，

shallbeprovidedwithbusbarsinpairbasedondemandsandthe

motorsofdualsetsofauxiliareuimentshallbesearatel

yqppy

，

connectedtothebusbarsinpaireachofwhichshouldbepowered

bsinletransformer.Iftheconfiurationofbusbarsinairmakes

yggp

，

itdifficulttoselecttransformercaacitandLVeuimentthe

pyqp

，

numberofbusbarsectionsmaybeincreasedorspecialstandby

modemabealied.

ypp

3.5.4Single-busbarconnectionshallbeadoptedforthelighting

busbarinthemainowerbuildinthatisoweredsearatel.Each

pgppy

oftheunitswithacaacitof200MWandabovemaberovided

pyyp

withonelightingtransformer.Ifamaintenancetransformeris

，，

rovideditmaactasthestandbowersul.Alsothelihtin

pyypppygg

transformersinstalledfortwounitsmaybackupeachother.An

（）

on-loadautomaticvoltageregulatorAVRwiththefunctionof

radedcomensationshouldbeinstalledonowersulincomin

gppppyg

，

feedersofthelightingbusbaroranon-loadtapchangershouldbe

aliedonthelihtintransformersothatthevoltaeofthe

ppggg

lihtinbusbarisautomaticallreulatedwithin100%to105%of

ggyg

/

380V220V.

3.6AuxiliarOeratinPowerSul

ypgppy

3.6.1MVauxiliaryoperatingpowersupplyshouldbefedas

：

follows

，

1IfgeneratorvoltagebusbarsareinstalledtheMVauxiliary

··

12owersourceshouldbefedfromthecorresondinbusbarsectionsto

ppg

theauxiliarypowerloadsoftheunitsinstalledonthecorresponding

；

busbarsections

2Iftheeneratorsandmaintransformersareconnected

g

，

inaunitmodetheMVauxiliarypowersourceshouldbefed

fromthelowvoltaesideofthemaintransformertoowerthe

gp

auxiliarypowerloadsoftheunits.

3.6.2TheconfiurationofMVauxiliaroeratinower

gypgp

：

sulshallcomlwiththefollowinrinciles

ppypygpp

，

1Forunitswithacapacityclassof50MWto125MWeach

unitshouldberovidedwithonedouble-windintransformeras

pg

theUAT.WhenthegeneratorvoltageisconsistentwiththeMV

，，

auxiliarowervoltaeUATmabeeliminatedorcurrent-

ypgy

limitinreactorsshallbeinstalledtolimittheshort-circuitcurrent

g

；

levelofMVauxiliarypowerbusbars

，

2Forunitswithacaacitclassof200MWto300MWeach

py

unitshouldbeprovidedwithonesplitwindingtypetransformeras

；

theUAT

，

3Forunitswithacaacitclassof600MWeachunit

py

，

maybeprovidedwithonesplitwindingtypetransformeror

oneslitwindintetransformerlusonedouble-windin

pgyppg

，；

transformerastheUAT

，

4Forunitswithacapacityclassof1000MWandabove

eachunitmaberovidedwithtwoslitwindinte

yppgyp

，

transformersoronesplitwindingtypetransformerplusone

，，

double-windintransformerastheUAToriftechnicalland

gy

，

economicallviableoneslitwindintetransformerma

ypgypy

suffice.WhentherearetwolevelsofMVauxiliarypower

··

13，

voltaethree-windintransformersmabealiedinrelace

ggyppp

ofsplitwindingtypetransformer.

3.6.3Theunitswithacaacitclassof125MWandbelow

py

shouldberovidedwithcircuitbreakersonauxiliarbranchlines.

py

Intheabsenceofcircuitbreakersmeetingtherequirementsfor

，

breakintheshort-circuitcurrentthecircuitbreakersthatmeet

g

，

peakwithstandcurrentrequirementmaybeappliedprovidedthat

relevantmeasuresshallbetakensuchthatthecircuitbreakersma

y

onlclearshort-circuitfaultswithintheallowableshort-circuit

y

，

current.Alternativelydisconnectorsorconnectionstrapswhich

meeteakwithstandcurrentreuirementmabealied.

pqypp

3.6.4Ifmetalenclosedisolated-phasebusbarisadoptedfor

，

auxiliarbranchlinesnocircuitbreakeranddisconnectorshall

y

beinstalledonsuchbranchlines.

3.6.5MVauxiliarypowerreactorsshouldbeinstalledbehind

，

thecircuitbreakerswhoseshort-circuitratinshort-timewithstand

g

，

currentpeakwithstandcurrentmaybecheckedundertheshort-

circuitconditionsoccurringbehindthereactors.Thereactorsmay

alsobeinstalledinfrontofthecircuitbreakersifthisarranement

g

isjustifiable.

3.6.6ForLVauxiliarowerbusbarssectionalizedbturbines

ypy

，，

orboilersorbdouble-circuitowersulchannelsitsoeratin

ypppypg

transformersshallbepoweredbycorrespondingMVauxiliary

busbarsections.

/

3.7AuxiliarStandbandStartuStandbPowerSul

yypyppy

3.7.1Theconfiurationandswitchovermodeofstandbower

gyp

supplyshallcomplywiththerelevantrequirementsincurrent

··

14nationalstandardGB50660CodeorDesinoFossilFired

fgf

PowerPlant.

3.7.2AuxiliarowerbusbarsofMVandLVowercenter

ypp

connectedwithClassⅠloadsshouldberovidedwithstandb

py

powersupplies.AuxiliarypowerbusbarsofMVandLVpower

centerconnectedwithClassⅡloadsmaberovidedwith

yp

standbypowersupplies.Auxiliarypowerbusbarsonly

connectedwithClassⅢloadsmanotberovidedwith

yp

standbowersulies.

yppp

/

3.7.3MVauxiliarystandbyorstartupstandbypower

suliesrovidedfortheentirelantshallhavethefollowin

ppppg

：

functions

，

1Ifnoeneratorcircuitbreakerorloadswitchisinstalled

g

/

MVstartustandbowersuliesmainlserveastheower

pypppyp

，

sourceforunitstartupandshutdownandconcurrentlyactas

auxiliarstandbowersourceandtheowersourceforunit

yypp

；

maintenance

2Ifgeneratorcircuitbreakersorloadswitchesare

，

installedMVauxiliarstandbowersuliesmainlserveas

yypppy

，

thepowersourceforunitemergencyshutdownand

concurrentlactasauxiliarstandbsourceandowersource

yyyp

forunitmaintenance.

，

3.7.4Forunitswithacapacityof50MWto125MWHV

（/）

auxiliarstandbstartustandbtransformersorreactorsshall

yypy

：

beconfiguredinaccordancewiththefollowingprinciples

1Iftheunitswithacaacitof100MWandbeloware

py

（），

rovidedwithsixormoreUATsreactorsanadditionalHV

p

（）；

auxiliarystandbytransformerreactormaybeinstalled

··

152Iftheunitswithacaacitof100MWto125MWare

py

arrangedinunitsystemandareprovidedwithfiveormore

，

UATsanadditionalHVauxiliarstandbtransformermabe

yyy

installed.

，

3.7.5Forunitswithacapacityof200MWto1000MWifno

，/

eneratorcircuitbreakerorloadswitchisinstalledHVstartu

gp

standbytransformersshallbeconfiguredinaccordancewiththe

：

followinrinciles

gpp

，

1Forunitswithacaacitof200MWto300MWone

py

/

HVstartupstandbytransformermaybeprovidedforevery

；

twounits

，

2Forunitswithacapacityof600MWto1000MWone

/

ortwoHVstartustandbtransformersmaberovidedfor

pyyp

；

evertwounits

y

/

3ThequantityandcapacityofHVstartupstandby

transformersshallbesufficienttomeetthefunctionalreuirements

q

ofstartuporstandbyofeitherofthetwounits.

，

3.7.6Forunitswithacapacityof300MWto1000MWif

，

eneratorcircuitbreakersorloadswitchesareinstalledHV

g

auxiliarystandbytransformersshallbeconfiguredinaccordance

：

withthefollowinrinciles

gpp

1Whenthehighvoltageauxiliarystandbypowersupplyof

theunitisconnectedfromthebusbarofhighvoltageswitchgearin

，

thelantfourorlessunitsthatmausehihvoltaeauxiliar

pyggy

standbypowersupplyofthesamecapacitymaybeprovidedwith

onehihvoltaeauxiliarstandbtransformer.Iffiveormoreunits

ggyy

mausehihvoltaeauxiliarstandbowersulofthesame

yggyypppy

，

capacitythentheymaybeprovidedwithonehighvoltageauxiliary

··

16oeratintransformerleftunconnectedinadditiontoonehih

pgg

；

voltageauxiliarystandbytransformer

2WhentheMVowersulforemerencshutdown

pppygy

oftheunitisconnectedfromtheauxiliarworkinbusbarat

yg

，，

theLVsideofUATofanotheruniti.e.atielineisprovided

betweenthecorresondinMVauxiliarowerbusbarsof

pgyp

unitssuchthattheyactasemergencyshutdownpowersource

，

foreachotherdedicatedHVauxiliarstandbtransformer

yy

mabeeliminatedandoneUATleftunconnectedmabe

yy

providedwherenecessary.

/

3.7.7WhentwoHVauxiliarstartustandbtransformersare

ypy

，

providedforeverytwounitsthecircuitbreakersanddisconnectors

attheHVsidesoftransformersshallbeconfiuredaccordinto

gg

therelevantreuirementsincurrentnationalstandardGB50660

q

CodeforDesignofFossilFiredPowerPlant.

/

3.7.8Thehihvoltaeauxiliarstandborstartustandb

ggyypy

：

powersupplyshallbeconnectedasfollows

，

1Ifthegeneratorvoltagebusbarisinstalledonestandby

；

owersulshouldbefedfromsuchbusbar

pppy

，

2Intheabsenceofgeneratorvoltagebusbarthesaid

owersulmabeconnectedfromtheMVbusbarwhichis

pppyy

atthelowestvoltagelevelacrosstheentireplantandprovided

（）

withreliablepowersupplyorfromthetertiaryLVwinding

，

oftietransformerandshallalsobeabletobesufficientl

y

poweredbyexternalpowersystemsinthecaseofpower

［

failureofthewholeowerlantincludinthecircumstance

ppg

（）

thattheMVmediumvoltaesidesofthree-windin

gg

］；

transformersarepoweredbytheHVsidesthereof

··

173Whentheeneratorcircuitbreakerisinstalledandthere

g

，

aretwoormoreunitstheauxiliaryworkingbusbaratLVsideof

theUATforoneunitmabeconnectedtotheMVstandbower

yyp

，，

sulofanotheruniti.e.atielineisrovidedbetweenthe

ppyp

correspondingMVauxiliarypowerbusbarsoftheunitssuchthat

theactastheowersourceforemerencshutdownforeach

ypgy

；

other

4Theowersulmabeoweredbdedicatedower

pppyypyp

linesconnectedtoexternalowerridsifustifiedthrouh

pgjg

；

techno-economicanalysis

5Iftwoormorehihvoltaeauxiliarstandbor

ggyy

/

startupstandbypowersuppliesareavailablefortheentire

，

owerlanttheowersuliesshouldbeconnectedfromtwo

ppppp

owersourcesindeendentofeachother.

pp

3.7.9Nodisconnectorshallbeinstalledonearthingwiresof

/

neutralointsofHVauxiliarstandborstartustandb

pyypy

transformerswhichareconnectedfromthepowergridata

voltagelevelofabove220kVwithneutralpointsdirectly

rounded.

g

3.7.10Whendedicatedstandbytransformerisadoptedfor

，

LVauxiliarstandbowerthestandbtransformershallbe

yypy

：

providedinaccordancewiththefollowingrequirements

1Iftheunitswithacapacityof125MWandbeloware

，

rovidedwitheihtormoreLVauxiliaroeratintransformers

pgypg

；

anadditionalLVauxiliarystandbytransformermaybeinstalled

2Evertwounitseachwithacaacitof200MWma

ypyy

；

shareoneLVauxiliarstandbtransformer

yy

3Eachunitwithacapacityof300MWandaboveshouldbe

··

18rovidedwithoneormoreLVauxiliarstandbtransformer.

pyy

3.7.11Iftwolowvoltageauxiliarytransformersareprovidedto

，

backueachothertheloadswhichserveasstandbforeachother

py

，

shallbeoweredbthesetwotransformersresectivelandno

pypy

automaticswitching-indevicesshallbeinstalledbetweenthetwo

transformers.

3.7.12TheClassⅡloadslocatedremotelyfromthemainpower

buildinshouldbeoweredbtwoneihborintransformerswhich

gpygg

serveasstandbforeachother.IftwoLVauxiliarower

yyp

，

transformerswhichserveasstandbyforeachotherareprovided

thennodedicatedstandbtransformershallbeinstalled.

y

3.7.13AnLVauxiliarystandbytransformerandanLV

auxiliaroeratintransformerwhosedutiesaretakenoverb

ypgy

theformerthrouhautomaticswitchinshouldnotbe

gg

connectedtothesameMVbusbarsection.

3.7.14Theconnectionrouofauxiliartransformersshallbe

gpy

selectedsuchthatphasesofauxiliaryworkingpowersuppliesare

consistentwiththoseofauxiliarystandbypowersuppliestoallow

arallelswitchinoftheauxiliarowersulies.LVauxiliar

pgypppy

，

powertransformersshouldbeconnectedinDynconfigurationand

，

wherereuiredotherconnectionconfiurationsmabeconsidered

qgy

instead.

3.7.15WhenonlyoneMVorLVauxiliarystandbyor

/

startustandbowersulisavailableforthewholeower

pypppyp

，

plantitshouldbeconnectedwithindividualauxiliarybusbar

：

sectionsasfollows

1Grouedbranchconnectionshouldbealiedforthe

ppp

，

auxiliarypowersupplyeachgroupconsistingfortwotofour

··

19；

busbarsections

2Isolatingdevicesshouldbeinstalledatthemainoutlet

/

atLVsidesofstandborstartustandbtransformers.

ypy

3.8ACEmergencyPowerSupply

3.8.1TheACemerencowersulforunitsrated

gypppy

200MWandaboveshallbeprovidedinaccordancewiththe

relevantreuirementsincurrentnationalstandardGB50660

q

CodeorDesinoFossilFiredPowerPlant.

fgf

3.8.2Thedieselgeneratorsetshallbeselectedinaccordance

withrelevantreuirementsinAendixD.

qpp

3.8.3ThevoltageandneutralearthingmethodofACemergency

owersulshallcomlwiththerelevantreuirementsin

pppypyq

currentnationalstandardGB50660CodeorDesinoFossil

fgf

FiredPowerPlant.

3.8.4Sinle-busbarconnectionshallbealiedforAC

gpp

emergencybusbarsectionsandshallbesectionalizedbyunits

andrespectivelysupplypowertoACemergencyloadsofthe

individualunits.

3.8.5EmergencybusbarsectionsshallbepoweredbyLV

secialormutualstandbowercenteroftheunitsdurin

pypg

，

normaloperationwhichshallbecapableofbeingswitchedto

ACemergencypowersuppliesonceitisdeterminedthatthe

owercenteroftheunitsreallfailstosulower.

pyppyp

3.9UninterrutiblePowerSul

pppy

3.9.1TheconfiurationandwirinmodeofACuninterrutible

ggp

powersupplyshallcomplywiththerelevantrequirementsin

··

20currentnationalstandardGB50660CodeorDesinoFossil

fgf

FiredPowerPlant.

3.9.2TheACuninterrutibleowersuloftheunitshould

ppppy

，

beoweredbonecircuitofACmainowersulonecircuitof

pypppy

ACbypasspowersupplyandonecircuitofDCpowersupply.The

ACmainowersulandACbassowersulshallbefed

pppyyppppy

fromdifferentauxiliarybusbarsections.Forunitsprovidedwith

，

ACemerencowersultheACmainowersulshouldbe

gypppypppy

fedfromsuchemerencowersul.TheDCowersulma

gypppypppyy

，

befedfromDCpowersupplyoftheunitorfromthebatterybanks

rovidedindeendentl.

ppy

3.9.3TheswitchingtimeofthebypassswitchesforAC

；

UPSshallnotbelonerthan5msinthecaseoflossoftheAC

g

，

auxiliarowersultheACUPSshallbeabletomaintain

ypppy

powersupplyfornolessthanhalfanhourunderfullload.

3.10WirinandSulModeofAuxiliarLoads

gppyy

3.10.1Auxiliarypowerloadsshallbeconnectedinaccordance

：

withthefollowinreuirements

gq

1Motorsusedfortheboilersandturbinegenerator

unitsshallberesectivelconnectedtotheircorresondin

pypg

MVandLVauxiliarypowerbusbarsections.Forunitswitha

，

capacityof50MWto60MWthemajorequipmentwhichback

ueachothermaeachbeoweredbtheowersulthat

pypypppy

；

servestheother

2Whereeachunitisrovidedwithtwosectionsofauxiliar

py

，

owerbusbarsdualsetsofauxiliariesshallberesectivel

ppy

connectedtothesetwobusbarsections.IfClassⅠMVandLV

··

21motorsareinterlockedinaccordancewiththetechnolo

gy

，

requirementstheyshallbeconnectedtothesamepowersupply

；

channel

，

3Intheabsenceofcommonbusbarsectionthecommon

loadsacrosstheentirepowerplantshallberespectively

connectedtoindividualauxiliarowerbusbarsections

yp

dependinguponloadcapacitiesanddemandsforpowersupply

，

reliabilitandshallbearoriatelmarshaled.Ifcommon

ypppy

，

busbarsectionsarerovidedthecommonl-usedmotorswhich

py

areclassifiedasClassⅠshallnotallbeconnectedtothesame

；

commonbusbarsection

4Wheneachunitrated200MWto1000MWwithout

turbine-drivenfeedwaterumsisrovidedwithtwoormore

ppp

，

motor-drivenfeedwaterumsthesemotor-drivenfeedwater

pp

pumpsshallberespectivelyconnectedtoindividualMV

workinbusbarsoftheunit.Ifthereisonesurlusmotor-driven

gp

，

feedwaterpumpthepumpshallbeconnectedtotwoMVworking

；

busbarsectionsoftheunit

5Forunitsrated300MWto1000MWwithturbine-

，

drivenfeedwaterpumpstheirmotor-drivenfeedwaterpumps

forstandbshouldbeconnectedtotheworkinbusbarof

yg

individualunits.

3.10.2MVauxiliarymotorsandLVauxiliarypower

transformersinthevicinitofthemainowerbuildinshould

ypg

beseparatelypoweredbytheMVauxiliaryworkingbusbar

，

sectionsinsidethemainowerbuildinormabeoweredb

pgypy

，，

acombinationofowersuliesi.e.twocommonbusbar

ppp

，

sectionsmaybeprovidedintheloadcenterwhichmaybe

··

22resectiveloweredbMVworkinbusbarsofdifferent

pypyg

units.

3.10.3IftheMVmotorsfarawafromthemainower

yp

，

buildinserveoneunitexclusiveltheshallbeconnectedto

gyy

；

MVauxiliarypowerworkingbusbarsectionsoftheunitif

，

thearesharedbtwounitsormorethefollowinwirin

yygg

：

modesmaybeapplied

1Switchearsmabeinstalledintheloadcenter.The

gy

workinandstandbowersuliesmabeoweredbtwo

gypppypy

ormorecircuitsofpowerlinesconnectedfromtheMV

auxiliarworkinbusbarsectionsofdifferentunits.The

yg

standbypowersupplymaybefedfromexternalpowergrid

；

instead

，

2Ifasubstationisrovidedattheloadcentertheworkin

pg

andstandbypowersuppliesmaybefedbytwocircuitsofpower

linesconnectedthrouhaste-utransformerfromtheMV

gpp

auxiliaryworkingbusbarsectionsbelongingtodifferentunitsor

，

thecommonbusbarsectionoftheunitsoralternativelyfedbytwo

circuitsofowerlinesconnectedtodifferentbusbarsectionsofthe

p

switchgearsratedbelow110kVinthepowerplant.

3.10.4Theowersulmodeofcentralumhouseshall

pppypp

：

bedeterminedinaccordancewiththefollowingprinciples

1Themotorsthatserveoneunitexclusivelymaybe

directlandsearateloweredbauxiliarowerworkin

ypypyypg

busbarsectionsofindividualunitsinsidethemainpower

；

buildin

g

2Ifonloneumhouseisconstructedintheentireower

yppp

，

planttwosectionsofdedicatedbusbarsmaybeprovidedinthe

··

23，

umhouseandthecirculatinwaterummotorsare

ppgpp

respectivelyconnectedtothetwobusbarsections.Twocircuitsof

workinowersuliesandonecircuitofstandbowersul

gpppypppy

areconnectedtotheauxiliarworkinbusbarsectionsofdifferent

yg

unitsinsidethemainpowerbuilding.Thestandbypowersupply

；

maalternativelbefedfromexternalowerrid

yypg

3Ifoneormorepumphousesareconstructedinthe

entireowerlantandthewatersulcaacitofthese

ppppypy

，

umhousesvariesinsinificantlonesectionofdedicated

ppgy

busbarmaybeprovidedineachpumphouse.Theworkingand

standbowersuliesareresectivelconnectedtoauxiliar

yppppyy

workingbusbarsectionsofdifferentunitsinsidethemain

owerbuildin.Thestandbowersulmaalternativel

pgypppyyy

；

befedfromexternalowerrid

pg

4Ifthepumphousesarefarawayfromthemainpower

，

buildinandtheloadsthereofarelareasubstationmaalso

ggy

beconstructedlocally.Theworkingandstandbypower

suppliesmaybefedbytwoormorecircuitsofpowerlines

connectedthrouhaste-utransformertoMVauxiliar

gppy

workingbusbarsectionsbelongingtodifferentunitsor

connectedtodifferentbusbarsectionsoftheswitchearsrated

g

below110kVinthepowerplant.

3.10.5LVmotorsinthemainpowerbuildingmaybepowered

（）

bsecialstandbowercenterPCandmotorcontrolcenter

ypyp

（），

MCCorbymutualstandbyPCandMCCandshallmeetthe

：

followinreuirements

gq

1TheowersulmodeofsecialstandbPCand

pppypy

：

MCCshallbedeterminedasfollows

··

24）

1ClassⅠmotorsaswellasClassⅡandClassⅢ

motorswithacapacityof75kWandaboveshouldbe

；

directloweredbthePC

ypy

）

2ClassⅡandClassⅢmotorswithacaacitbelow

py

；

75kWshouldbepoweredbytheMCC

）

3IncaseoftwoClassⅠmotorswithacaacitof

py

5.5kWandbelowwhichserveasstandbyforeach

，

otherthemabeoweredbMCCsindifferent

yypy

；

busbarsectionsofthePC

）

4TheMCCconnectedwithClassⅡloadsshallbe

（）

oweredbmanuallswitcheddulicateower

pyypp

supplies.TheMCCconnectedwithClassⅢloads

onlmabeoweredbasinleowersul.

yypygpppy

2TheowersulmodeofmutualstandbPCand

pppyy

：

MCCshallbedeterminedasfollows

），

1LVauxiliartransformersPCsandMCCsshouldbe

y

providedinpairssoastoestablishdouble-circuitpower

supplychannels.TwoLVauxiliarytransformersin

；

mutualstandbshallbemanuallswitched

yy

）

2MCCsinpairsshouldbepoweredbythesinglepower

sulofcorresondinPCs.Motorsinairsshallbe

ppypgp

respectivelypoweredbythecorrespondingPCsand

；

MCCs

）

3Motorswithacaacitof75kWandaboveshouldbe

py

poweredbyPCsandthosewithacapacitybelow

；

75kWshouldbeoweredbMCCs

py

）

4OneClassⅠorClassⅡmotorshallbeindividuall

y

providedwithonemotorcontrolcenterwithdual

··

25，

owersulieswhichshallbeconnectedtodifferent

ppp

；

PCsthedualpowersuppliesoftheMCCsconnected

toClassⅠloadsshallbeswitchedautomaticalland

y

thoseoftheMCCsconnectedtoClassⅡloadsma

y

bemanuallyswitched.

3.10.6TheowersulmodeofLVmotorsoutsidethe

pppy

：

mainpowerbuildingshallbedeterminedasfollows

，，

1Ifloadcentersofworkshossuchascoalhandlin

pg

，

ashhandlinandchemicalwatertreatmentworkshosoil

gp

（），

pumphousesandESPelectrostaticprecipitatorworkshops

arefarawafromthemainowerbuildinandhavelare

ypgg

，

capacitytheyshouldbeseparatelyprovidedwithtransformers

forowersulandthestandbowersulthereofshall

pppyypppy

berovidedwithautomaticormanualswitchin-indevices

pg

dependinguponimportanceoftheloads.Ifthesaidloadsareof

，

lowcaacitandnearthemainowerbuildinthemabe

pypgyy

；

directlypoweredbyPCsorMCCsinthemainpowerbuilding

2The380Vmotorgroupofdeep-wellpumpsshouldbe

oweredbtransformer-motorrouTbranchthrouh

pygpg

dedicatedMVandaboveoverheadtransmissionline.

3.10.7ThewirinmodeofMCCoweredbdualower

gpyp

suppliesthataremanuallyswitchedshallbedeterminedas

：

follows

1Iftwocircuitsofowersulincominlinesarefed

pppyg

，

fromthesametransformertwopairsofsingle-throwincoming

linedisconnectorscaableofinterrutintheratedcurrent

ppg

；

mabealiedforconnection

ypp

2Iftwocircuitsofpowersupplyincominglinesarefed

··

26，

fromdifferenttransformersoneairofdouble-throw

p

disconnectorscapableofinterruptingtheratedcurrentortwo

airsofsinle-throwdisconnectorscaableofinterrutinthe

pgppg

ratedcurrentandblockinforeachothershallbealiedfor

gpp

connection.

3.10.8Thecoalfeedermotorofdirect-firedulverizedcoal

p

systemanditscorrespondingcoalpulverizerandauxiliary

euimentshouldbeconnectedtothesameowersul

qppppy

channel.

3.10.9Thepowersupplymodeofpulverizedcoalfeeder

：

motorsshallbedeterminedasfollows

1IftheLVmotorsinthemainpowerbuildingare

，

oweredbsecialstandbPCsandMCCseachboilershallbe

pypy

rovidedwithtwodistributionboxesindeendentofeachother.

pp

Single-busbarconnectionshallbeappliedfordistributionboxes.

Theulverizedcoalfeedermotorsshallbeconnectedto

p

thetwodistributionboxesontheprinciplethatboilersshallbe

abletocontinuetooperateinthecaseoffailureofhalfof

ulverizedcoalfeedermotors.

p

Eachdistributionboxshallbeprovidedwithoneworking

owersulandonestandbowersul.Theworkin

pppyypppyg

powersupplyandstandbypowersupplyshallbeconnectedto

differentbusbarsectionsofthespecialstandbyPC.During

，

normaloerationtheworkinowersuliesoftwo

pgppp

distributionboxesshallbefedbydifferentbusbarsectionsof

thesecialstandbPC.

py

Iftheworkinowersulofthedistributionboxfails

gpppy

，

whilethestandbypowersupplythereofisstillavailablethe

··

27distributionboxshallbeautomaticallswitchedtothestandb

yy

powersupply.Incasethatbothworkingandstandbypower

，

sulfailsimultaneousltheshallbeswitchedoffwitha

ppyyy

timedelasoastoreventexlosionoftheboileralread

yppy

stoppedasaresultofre-feedingofpulverizedcoaloncethe

owersulisrestored.

pppy

2IftheLVmotorsinthemainpowerbuildingare

，

oweredbmutualstandbPCsandMCCsthedistribution

pyy

boxesoweredbsinleowersuliesmaberovidedfor

pygpppyp

eachboilerdependinguponthenumberoflayersorgroupsof

ulverizedcoalfeedinnozzles.Ifthesaidnumberoflaersor

pgy

，

groupsisanoddnumberoneadditionaldistributionboxmay

beinstalledsothatonelaerorrouofulverizedcoal

ygpp

feedinnozzlesisoweredbtwodistributionboxes.

gpy

Thedistributionboxesshallberespectivelyconnectedfrom

，

twomutualstandbPCs.Alternativeldeendinuonthe

yypgp

，

technologyrequirementsonelayerorgroupofthepulverizedcoal

feedingnozzlesmaybepoweredbyonedistributionboxandthe

distributionboxshallbeconnectedtotwomutualstandbPCs

y

whichareabletoautomaticallyswitchedtooneanother.

/

3Simleonofftwo-stateswitchesinsteadofbutton

p

switcheswithself-holdingshuntcircuitsshallbeappliedfor

ACcontactorsofpulverizedcoalfeedermotorcircuitsfor

uroseofreliableclosinthereofoncetheowersulis

ppgpppy

restored.

4Powersuliesofthesnchronousoeratorsofulverized

ppypp

coalfeedermotorsshallbeconnectedtocorresondinbusbarsof

pg

distributionboxesofpulverizedcoalfeeders.Powersuppliesof

··

28variableseedovernorandcontrollerofulverizedcoalfeeder

pgp

motorsshallbeconnectedtothepowersupplycircuitsthereof.

3.10.10TheowersulmodeofI&Cdistributionboards

pppy

：

shallbedeterminedasfollows

，

1Forunitswithacapacityof125MWandbelowthe

I&Cdistributionboardofeachturbineandboilershallbe

；

respectivelypoweredbytwocircuitsof380Vpowersupply

，

2Forunitswithacaacitof200MWandabovethe

py

I&Cdistributionboardofeachturbineandboilershallbe

，

respectivelypoweredbytwocircuitsof380Vpowersupply

oneofwhichshallbeconnectedfromPCsandtheothershall

；

beconnectedfromACemergencybusbarsections

3IfneutralointsofLVauxiliarowersstemsare

pypy

，

notdirectlroundedI&Cdistributionboxesshouldbe

yg

providedwithisolatingtransformerswhoseneutralpointsat

thesecondarsidearedirectlrounded.

yyg

3.10.11Thepowersupplymodeofnormallightingsystem

：

inthemainpowerbuildingshallbedeterminedasfollows

1IfneutralointsofLVauxiliarowersstemsare

pypy

directlygroundedandthecapacityoftheunitis125MWand

，

belowthenormallihtinsstemshouldbeoweredbLV

ggypy

；

auxiliarytransformerssharedbypowerandlightingnetworks

2IfneutralpointsofLVauxiliarypowersystemsarenot

，

directlroundedorthecaacitoftheunitis200MWandabove

ygpy

thenormallightingsystemshouldbepoweredbylighting

transformersconnectedfromMVorLVauxiliarowersstem.

ypy

ThelihtintransformersconnectedfromtheLVauxiliarower

ggyp

systemsmayalsobearrangedinadispersemanner.

··

293.11LVMaintenancePowerSulNetwork

ppy

3.11.1StationarACLVmaintenanceowernetworksshall

yp

berovidedinowerlantsandmaintenanceowersul

ppppppy

boxesshallbeprovidedatmaintenancesitesforsupplyof

，

owertoeuimentsuchaselectricweldinmachineselectric

pqpg

toolsandtestdevices.Thecapacityofthemaintenancepower

sulshallbedeterminedbasedontheloadsoftheelectric

ppy

weldinmachines.

g

3.11.2Themaintenancepowersupplynetworksshouldbe

oweredbrouedbranchesofsinleowersulandthe

pygpgpppy

：

wiringmodeshallmeetthefollowingrequirements

1Thenetworksshouldbeconnectedfromcorresondin

pg

PCsinthemainowerbuildin.Incaseofthree-hasethree-

pgp

，/

wire380Vauxiliarypowersystems380220Vtransformers

mabeinstalledinthemaintenanceowerdistributionboxes

yp

；

forsupplyof220Vmaintenancepower

2Unitswithacapacityof300MWandabovemaybe

rovidedwithdedicatedmaintenancetransformerswiththeir

p

；

LV-sideneutralsdirectlygrounded

3Themaintenanceowerdistributionboxesoutsidethe

p

mainpowerbuildingshouldbeconnectedfromthenearby

powerdistributionboards.

3.11.3Thelocationanduantitofmaintenancedistribution

qy

boxesmaybedeterminedinaccordancewithAppendixE.The

maximumlenthofleadlinesofelectricweldinmachinesma

ggy

betakenas50m.

3.11.4Thenumberofcircuitsofthemaintenancedistribution

··

30boxesinthemainowerbuildinshallnotbelessthanfourand

pg

，

enclosedswitchessocketsandreadilyreplaceablefusesshouldbe

installedinthedistributionboxes.

3.11.5Themaintenanceowersulnetworksshallbe

pppy

providedwithresidualcurrentoperatedprotectivedevices.

Residualcurrentoperatedprotectivedevicesmaybeinstalled

attheswitchesofincominowersuliesofmaintenance

gppp

，

boxesorrovidedforeachfeedercircuitresectivel

ppy

dependingonthenumberoffeedercircuits.Whenthenumber

，

offeedercircuitsisfourormoreeachcircuitshouldberovided

p

witharesidualcurrentoeratedrotectivedevice.

pp

··

31/

4SelectionofAuxiliarTransformer

y

ReactorandCheckofMotorVoltaedurinStartu

ggp

4.1LoadCaacitCalculation

py

，

4.1.1Todeterminethecaacitofauxiliarowersul

pyypppy

theauxiliarowerloadsoftheowerlantshallbefirst

yppp

calculatedbasedontheossiblemaximumoerationmodeof

pp

：

auxiliaryequipmentinaccordancewiththefollowingprinciples

1Theeuimentincontinuousoerationshallbetaken

qpp

；

intoaccountinthecalculation

2Euimentwhichoeratescontinuouslbutinfreuentl

qppyqy

；

durinoerationofunitshallalsobetakenintoaccount

gp

3Equipmentwhichoperatesfrequentlyforashorttimeor

oeratesfreuentlonintermittentbasisshouldbetakeninto

pqy

，

account.Incalculationtheloadsofsuchequipmentmaybe

roerlconvertedbconsiderintheiractualeffectson

ppyyg

；

temperatureriseoftransformer

4Equipmentwhichoperatesinfrequentlyandforashort

timeandoeratesinfreuentlonintermittentbasisshallnot

pqy

，

betakenintoaccount.Howeverallofsuchequipmentpowered

；

breactorsshallbeconsidered

y

5Fordevicesthatbackupeachotherandarepoweredbythe

，；

sameauxiliarowersulonlconsidertheoeratindevice

ypppyypg

6Devicesthatbackueachotherandareoweredb

ppy

differentauxiliarypowersuppliesshallbealltakeninto

··

32；

account

，

7Forotherdevicestheirloadsshallbecalculatedin

；

accordancewiththerelevantreulationsinAendixF

gpp

，

8Incaseofslit-windintransformerstheloads

pg

flowingthroughtheMVandLVwindingsshallberespectively

calculated.IfthetwoLVwindinsareconnectedtodevices

g

，

whichserveasstandbyforeachotherthentheMVwindings

shallbecalculatedinaccordancewithItem5ofthisSection

andtheLVwindinsmabecalculatedinaccordancewith

gy

；

Item6ofthisSection

9ThecalculatedcaacitofLV-sideloadsofworkinMV

pyg

auxiliarytransformersofaunitmaybetakentobethetotal

caacitofmutualstandbLVauxiliartransformersoftheunit

pyyy

multiliedb0.5lusthecalculatedcaacitoftheLVauxiliar

pyppyy

；

transformerwiththelargestcapacitymultipliedby0.5

，

10Incaseofslitreactortheloadflowinthrouheach

pgg

armthereofshallberespectivelycalculatedinaccordancewith

；

thesameprinciplesasthoseforordinaryreactors

11Theoeratinmodesofauxiliarowerloadsmabe

pgypy

determinedasperAppendixB.

4.1.2The＂conversioncoefficient＂methodor＂shaftower＂

p

methodmabealiedforloadcalculation.Thecalculation

ypp

methodsshallmeettherelevantregulationsinAppendixF.

/

4.2TransformerReactorSizin

g

4.2.1ThecapacityofUATsshouldbeselectedtobethe

sumofthecalculatedauxiliarowerloadsofMVmotorsand

yp

thecalculatedloadsofLVauxiliarypower.

··

334.2.2ThecaacitofLVauxiliaroeratintransformer

pyypg

withcoldstandbytransformersshouldhaveamarginof10%.

ThecaacitofLVauxiliaroeratintransformerswithhot

pyypg

standbtransformersmahaveazeromarin.

yyg

4.2.3Thecapacityofauxiliaryreactorsshallbeselectedin

/

comliancewithrelevantreuirementsinDLT5222Desin

pqg

TechnicalRuleforSelectingConductorandElectrical

，

Euiment.Inadditionaroriatemarinsshouldbereserved

qppppg

therefor.Alsothecaacitmabeincreasedbonelevelifitis

pyyy

economicallyviable.

4.2.4Thecaacitofstandbauxiliartransformers

pyyy

（）/

reactorsorstartupstandbytransformersshallbeselected

：

accordintothefollowinreuirements

ggq

，

1Inabsenceofeneratorcircuitbreakerorloadswitch

g

（）

thecapacityofHVauxiliarystandbytransformersreactors

/

orstartustandbtransformersshallnotbelessthanthatof

py

（）

thelargestunitauxiliarytransformerreactor.

，

2Ifgeneratorcircuitbreakerorloadswitchisprovided

（）

thecaacitofHVauxiliarstandbtransformersreactors

pyyy

/

orstartupstandbytransformersshallmeetthefollowing

：

reuirements

q

）

1IfadedicatedHVauxiliarystandbytransformeris

providedanditservesasnotonlythepowersupply

，

incaseofemerencshutdownbutalsothestandb

gyy

，

ofUATduringmaintenancethecapacityofthe

standbunitauxiliartransformershouldbetaken

yy

as100%ofthecaacitofthelarestworkinunit

pygg

；

auxiliarytransformerifitonlyservesasemergency

··

34，

owersulitscaacitmabetakenas60%of

pppypyy

；

thecapacityofthelargestworkingHVtransformer

），

2IfnoHVauxiliarstandbtransformerisrovided

yyp

MVshutdownowersulshallberovided.The

pppyp

capacityofMVshutdownpowersupplyshall

，

accommodateemerencshutdownoftheunitand

gy

thecapacityrequiredforemergencyshutdownofthe

unitshallbedeterminedaccordintotheactual

g

roectconditions.

pj

，

4.2.5IfcoldstandbyLVauxiliarytransformerisprovided

itscaacitshallbeeualtothatofthelarestLVauxiliar

pyqgy

operatingtransformer.

4.2.6WhendetermininthecaacitofdedicatedLVauxiliar

gpyy

transformerswhicharecentrallconnectedwithvariablefreuenc

yqy

，

converterstheconversioncoefficientusedforcalculatingload

caacitofthevariablefreuencconvertersshallbetakenas

pyqy

1.25.

4.3VoltaeReulationandReulatinModes

gggg

4.3.1Givennormalvariationofauxiliarypowersupply

，

voltaeandauxiliarowerloadsthefluctuationofvoltaeof

gypg

auxiliarypowerbusbarsatdifferentratingsshouldnotexceed

-5%to+5%ofnominalvoltage.Thecalculationofvoltage

reulationshallbeincomliancewithAendixG.

gppp

4.3.2Thefluctuationlimitsofpowersupplyvoltageshallbe

determinedbasedonthesecificconditionsofowerlant.

ppp

Thefluctuationlimitsofvoltaeateneratoroutletmabe

ggy

consideredtobe5%.

··

35，

4.3.3Inabsenceofeneratorcircuitbreakerorloadswitch

g

（）

transformerswithOLTCon-loadtapchangershallnotbe

aliedastheUATsconnectedtoeneratoroutletinorderto

ppg

imroveoerationreliabilitoftheunit.

ppy

，

4.3.4Ifgeneratorcircuitbreakerorloadswitchisprovided

UATormaintransformershoulduseon-loadtachaner

pg

（）

OLTCtransformerinordertoaccommodatethevoltage

deviationofauxiliarowerbusbarsatdifferentratinsdurin

ypgg

startuoftheunit.Ifthecalculationandcheckshowthat

p

auxiliarypowerbusbarvoltagemeettherequirementofArticle

，（）

4.3.1NLTCno-loadtachanertransformermaalsobe

pgy

applied.

/

4.3.5IftheimedancevoltaeofHVauxiliarstartu

pgyp

standbtransformersismorethan10.5%orthevoltaeatthe

yg

，

connectionnodefluctuatesbymorethan95%to105%OLTC

transformersshouldbealied.Ifthecalculationandcheck

pp

showthatauxiliarypowerbusbarvoltagemeetsthevoltage

deviationrequirementofauxiliarypowerbusbarsatdifferent

，

ratinsNLTCtransformermaalsobealied.

gypp

4.3.6Thevariationofvoltageattheconnectionnodeof

/

auxiliarstartustandbtransformersshallallowforthe

ypy

voltaefluctuationcausedbloadflowvariationinthecaseof

gy

blackoutofthewholepowerplant.

4.4Short-circuitImedanceSelection

p

，/

4.4.1TheimpedanceofUATHVstartupstandbytransformer

orMVauxiliarreactorshouldbesoselectedthattheauxiliar

yy

powersystemmayuseswitchgearswithlowershort-circuitrating

··

36androvidethevoltaelevelreuiredfornormalstartuofmotors

pgqp

andforself-startingofgroupedmotors.

4.4.2Tomeetthevoltaedeviationreuirementofauxiliar

gqy

，

owerbusbarsatdifferentratinstheimedancevoltaeof

pgpg

workingMVauxiliarytransformershouldnotbehigherthan

10.5%.

4.4.3Whendeterminingimpedanceofunitauxiliarytransformer

，

orreactortheeffectontheminimumthermostablecross-sectional

，

areaofcablesshallalsobeconsidered.Inadditiontheimedanceof

p

reactorsshallbeselectedtomeettheirownshort-timewithstand

currentandeakwithstandcurrentreuirements.

pq

4.4.4Asforhigh-capacitygeneratorsimposedwithleading

，

haseoerationreuirementstheimedanceselectionand

ppqp

voltaereulationmodeoftheauxiliartransformersshallbe

ggy

determinedthroughcomprehensivetechnicalandeconomical

comarisons.

p

4.4.5TheimpedanceofLVauxiliarytransformershallbe

determinedaccordingtoshort-circuitcurrentwithstandcapability

ofLVelectricalaaratuses.Aslonastheshort-circuitratinof

ppgg

，

LVelectricalapparatusissufficienttocutoffshort-circuitcurrent

thetransformerwithstandardimedanceshouldbeselected

p

preferablyamongtheoneswithdifferentcapacities.

4.5CheckofVoltaeofAuxiliarBusesand

gy

MotorsdurinNormalStartin

gg

4.5.1Duringnormalstart-upofthemotorwiththehighest

，

owerthevoltaeofauxiliarowerbusbarsshallnotbeless

pgyp

than80%ofratedvoltage.

··

374.5.2Theterminalvoltaeofthemotorswhichmabe

gy

readilstartedushallbenolessthan70%ofratedvoltae

ypg

duringstartup.Thestart-upvoltageofthemotorswhichare

extremeldifficulttobestartedushallbeincomliancewith

ypp

thereuirementsasexresslandreasonablsecifiedb

qpyypy

manufacturers.Calculationofstartingvoltageofrelevant

motorsshallbeincomliancewithAendixH.

ppp

（）

4.5.3IftheratedowerofthemotorsinkWismorethan

p

（·），

20%ofthepowersupplycapacityinkVAthevoltage

，

levelthereofduringnormalstartupshallbechecked.Howeverthe

/

voltaeof6kV10kVmotorswithacaacituto2000kWma

gpypy

notbecheckedintermsofthenormalstart-uvoltae.

pg

4.6CheckofVoltaeofAuxiliarBusbars

gy

duringGroupedMotorsSelf-starting

4.6.1Thevoltaeofauxiliarowerbusbarsdurinself-

gypg

startinofrouedmotorsshallbecheckedsoastoensure

ggp

successfulself-startingofClassⅠmotors.Thevoltageof

auxiliarypowerbusbarsduringself-startingshallnotbelower

thanthoseaslistedinTable4.6.1.

Table4.6.1Minimumvoltageofauxiliarypower

busbardurinself-startinofrouedmotors

gggp

（）

DesinationSelf-startinmodeSelf-startinvoltae%

gggg

MVauxiliarowerbusbar65to70

yp

Separateself-startingof

60

LVbusbars

LVauxiliarowerbusbar

yp

Startupofseries-connected

55

LVandMVbusbars

··

38，

4.6.2Forauxiliaroeratinowersulself-startinof

ypgpppyg

groupedmotorsaftervoltagelossmayonlybeconsidered.

/

Standbauxiliarorstartinstandbowersulshall

yygypppy

：

accommodatethefollowinthreestartinmodes

gg

：

1No-loadself-startingstandbypowersupplyunder

no-loadconditionisautomaticallswitchedintoservethe

y

；

workingsectionwherepowersupplyislost

：

2Self-startininthecaseoflossofvoltaereferstothe

gg

self-startinincaseswhereemerencundervoltaedurin

ggygg

；

operationisclearedandthevoltagerecovers

：

3On-loadself-startinafterthestandbowersul

gypppy

，

hasbeenservingsomeloadsitisautomaticallyswitchedinto

servetheworkinsectionwhereowersulislost.

gpppy

，

4.6.3AsforLVauxiliartransformerstheoeratin

ypg

conditionsduringsimultaneousself-startingofseries-connected

MVandLVauxiliarowerbusbarsshallbechecked.

yp

4.6.4Thevoltageofauxiliarypowerbusbarswhengrouped

motorsareself-startedshallbecalculatedaccordingtoAppendixJ.

4.7HarmonicsRestraining

4.7.1Theeffectsofvoltaeandcurrentharmonicsonower

gp

qualityofauxiliarypowersystemandrelevantelectrical

equipmentshallbefullyconsideredindesignofauxiliary

owersstemofowerlants.Aroriatemeasuresshallbe

pyppppp

takentoensuresafeandreliableoperationofelectrical

euimentinharmonicenvironment.

qp

4.7.2Voltaeandcurrentharmonicsofauxiliarower

gyp

/

systemmainlyoriginatefromrectificationinversionpartsof

··

39/

variousMVLVvariablefreuencconverters.Whenselectin

qyg

，

variablefrequencyconvertersthefrequencyconversion

rincilesofdifferentfreuencconversiondevicesshallbe

ppqy

，

analzedossibleharmonicharmsshallbeevaluatedand

yp

comparedsoastoselectsuitablefrequencyconversiondevices.

4.7.3TheLVvariablefreuencconverterscentrallrovidedin

qyyp

auxiliarypowersystemshallbepoweredbydedicatedLV

auxiliartransformerswhicharesolelintendedfortheloads

yy

ofvariablefreuencconverters.Otherloadsthanvariable

qy

frequencyconvertersshouldbepoweredbyotherLVauxiliary

transformers.

4.7.4ForspecialLVauxiliarytransformersthatarecentrally

，

connectedwithvariablefreuencconverterssuitablevectorrou

qygp

shouldbealiedtoeffectiveloffsettheodd-ordercurrent

ppy

harmonicsinMVauxiliarybusbar.

4.7.5Thefollowinharmonicssuressionmeasuresma

gppy

：

betakeniftheyaretechnicallyandeconomicallyfeasible

decreasetheproportionofharmoniccomponentsbyincreasingthe

，

caacitofLVtransformersreducintheimedanceofthe

pygp

；

transformersandincreasingthesystemsshort-circuitcapacityuse

electricaleuimentwithrelevantcaabilitiestoimroveits

qppp

harmonicswithstandingcapacity.

4.7.6ForLVbusbarsthatarecentrallyconnectedwiththeloads

，

ofvariablefreuencconvertersmeasuressuchasinstallin

qyg

additionalfiltersmaybetakentosuppresstheeffectsofharmonics.

，

4.7.7Tosuressharmonicsinauxiliarowersstemthe

ppypy

relevantelectricaleuimentshouldbereasonablselected

qpy

accordingtothetypeofvariablefrequencyconvertersthe

··

40，

harmonicseneratedbthem.Inadditionmeasuresshallbe

gy

，

takeninrespectofvariablefrequencyconverterselectronic

，，

devicesandtheircableaccessoriescablelainroutes

yg

，

shieldinmeasuresearthinsstemtominimizethesatial

ggyp

electromagneticinterferenceofhigherharmonicsonelectronic

devicesandachievesafeandreliableoperationofelectronic

devicesinharmonicenvironment.

··

415Motors

5.1TypeSelection

5.1.1HihefficiencACmotorsshouldbealiedforthe

gypp

auxiliarysystem.DCmotorsmaybeappliedfortheequipment

whichisreuiredtobecontinuousloeratedinthecaseof

qyp

lossofACauxiliarowersulies.

yppp

5.1.2SquirrelcagetypemotorsshouldbeappliedasAC

auxiliarmotors.Deeslotordoublesuirrelcaetemotors

ypqgyp

shallbeappliedfortheequipmentwhichrequireslargestarting

torue.AsforClassⅠmotorwhichisstartedwithheav

qy

，

dutythecoordinationmarginbetweenthemotorcapacityandthe

，

shaftowershallbecheckedwithvariousrocessdiscilinesor

ppp

，

secialmotorswithhihstartintorueshallbealiedsoasto

pggqpp

meetrequirementsofself-starting.Woundtypemotorsmaybe

aliedformachineswhicharestartedreeatedlorwithheav

pppyy

dutyorwhichrequirespeedgoverningwithinalimitedrange.

，

5.1.3Toenhanceoperationaleconomydouble-speedmotors

mabealiedorvariablefreuencdriveorotherseedreulation

yppqypg

measuresmaybetakenforlarge-capacityauxiliaryequipmentof

unitsrated200MWorabove.

5.1.4Whenprocesssystemplacesvariablefrequencydrive

，

reuirementsonauxiliareuimentaattentiontosuch

qyqppy

variablefreuencdrivereuirementsandthereuirementson

qyqq

motorsplacedbyvariablefrequencyconvertersdesignedwith

··

42differentfreuencconversionrinciles.Motorsseciall

qypppy

designedforvariablefrequencydrivemaybeappliedifnecessary.

5.1.5Theenclosurerotectionclassandcoolinmethodofmotors

pg

shallbeinconsistentwiththesurroundinenvironmentconditions.

g

TheenclosureprotectionclassshallbeIP54inmoistanddusty

workshosanditmabeIP23orhiherinotherordinarlocations.

pygy

Explosion-proofmotorsshallbeappliedatlocationswithpotential

exlosionhazards.

p

5.1.6Secialmotorsshallbealiedinsecialenvironment

pppp

，

suchasplateautropicsandoutdoors.

5.2RatinofVoltaeandCheckofCaacit

ggpy

，

5.2.1Whendeterminintheratedvoltaeofmotorsthecaacit

ggpy

，

andimedanceofworkinMVauxiliartransformersshort-circuit

pgy

currentlevelofMVauxiliarybusbarandotherrelevantfactors

，

shallbecomrehensivelconsideredwhilethefollowinrinciles

pygpp

：

shallalsobefollowed

，

1If6kVlevelisadoptedforMVauxiliarypowersystemthe

ratedvoltaeofmotorsof200kWorabovemabedeterminedto

gy

，

be6kVandthatofmotorsbelow200kWshouldbe380Vandthat

ofmotorsofaround200kWmabedeterminedaccordintoactual

yg

projectconditions.

2Ifonly10kVlevelisadoptedforMVauxiliarypower

，

sstemtheratedvoltaeofmotorsabove250kWmabe

ygy

，

determinedtobe10kVthatofmotorsbelow200kWshouldbe

，

380Vandthatofmotorbetween200kWand250kWmabe

y

determinedaccordintoactualroectconditions.

gpj

3Iftwolevels10kVand6kVareadoptedforMVauxiliary

··

43，

owersstemtheratedvoltaeofmotorsabove4000kWshould

pyg

，

bedeterminedtobe10kVthatofmotorsbetween200kWand

，

4000kWshouldbe6kVthatofmotorsbelow200kWshouldbe

，

380Vandthatofmotorsofaround200kWor4000kWmabe

y

determinedaccordingtoactualprojectconditions.

4Iftwolevels10kVand3kVareadotedforMVauxiliar

py

，

powersystemtheratedvoltageofmotorsabove1800kWshould

，

bedeterminedtobe10kVthatofmotorsbetween200kWand

，

1800kWshouldbe3kVthatofmotorsbelow200kWshouldbe

，

380Vandthatofmotorsaround200kWand1800kWmaybe

determinedaccordintoactualroectconditions.

gpj

5Formotorswhosecapacitiesareattheboundary

，

ointsoftheaboveranesthevoltaeratinofonelevellower

pggg

shouldbealiedrovidedthattheshort-circuitcurrentof

ppp

variousMVauxiliarybusbarsectionsisminimizedandthe

reuiredstartinvoltaemabeensured.

qggy

5.2.2Whenmotorsactualserviceconditionsareinconsistent

，

withtheconditionsspecifiedbythemotormanufacturerthe

caacitiesofmotorswithhihrotationalinertiaorthosewhich

pg

arestartedwithheavydutyshallbecheckedfortheirstarting

conditions.

5.2.3Thecapacityofsquirrelcagetypemotorsshallbe

checkedbycarryingouttwocoldstartsoronewarmstart.The

calculationsshallbeincomliancewithrelevantreulationsin

pg

AppendixK.

，

5.2.4Formotorsusedin1000mto4000mhih-altitudeareas

g

ifthehihestambienttemeratureintheareadecreaseswiththe

gp

，

altitudeandmeetsFormula5.2.4thentheratedpowerofmotor

··

44；

shallremainunchanedifthehihestambienttemeratureinthe

ggp

，

areadoesnotmeetFormula5.2.4thepartofFormula5.2.4

，

aheadof＂≤＂shallalandtheavailablecaacitofmotorshall

ppypy

bedecreasedb1%forever1℃bwhichthecalculationresultis

yyy

higherthan0℃orbedeterminedbyconsultingwiththemotor

manufacturer.

h-1000

（）（）

ΔQ-40-θ≤05.2.4

100

，—（）；

wherehaltitudeoftheaream

—

ΔQincrementoftemeratureriseofmotorforaltitude

p

，

increaseof100mwhichis1%ofratedtemerature

p

（）；

riseofmotor℃

—，

θthehihestambienttemeratureoftheareawhich

gp

mabetakenasthemeanhihesttemeraturein

ygp

thelocalhottestmonthplus5℃.

··

456Short-circuitCurrentCalculationand

ElectricalEuimentandConductorSelection

qp

6.1Short-circuitCurrentCalculationinMVAuxiliar

y

PowerSstem

y

6.1.1Thecalculationofshort-circuitcurrentofMVauxiliary

powersystemandselectionandcheckoftherelevantelectrical

euimentandconductorsshallcomlwiththerelevant

qppy

/

reuirementsinDLT5222DesinTechnicalRuleorSelectin

qgfg

ConductorandElectricalEquipment.

6.1.2Theshort-circuitcurrentofMVauxiliarower

yp

，

sstemissourcedfromtwoartsresectivelauxiliarower

yppyyp

suppliesandmotors.Itshallbecalculatedasthearithmetic

sumofthetwoshort-circuitcurrentswiththesamehase

p

anle.

g

6.1.3Normalwiringconfigurationwhichmaycausemaximum

short-circuitcurrentshallbetakenintoaccountforcalculationof

short-circuitcurrentandtheshort-timearalleloerationmode

pp

duringmanualorautomaticswitchoverneednotbeconsidered.

6.1.4Incalculationofshort-circuitcurrentofMVauxiliary

，

owersstemtheeffectoffeedbackcurrentofmotorsonthe

py

short-timewithstandcurrentandeakwithstandcurrentof

p

electricalequipmentandconductorsandthebreakingcurrent

，

ofcircuitbreakersshallbetakenintoaccountandtheneative

g

toleranceofshort-circuitimedanceofunitauxiliar

py

··

46transformersoriinatinfrommanufacturinrocessshallalso

gggp

beconsidered.Theshort-circuitcurrentallowingforfeedback

currentofasnchronousmotorsmabecalculatedusinthe

yyg

methodiveninAendixL.

gpp

6.1.5Symmetriccomponentoftheshort-circuitcurrent

suppliedbyauxiliarypowersuppliesmaybeconsideredtobe

notsubectedtoattenuationdurintheentireshortcircuit

jg

，

rocessandasmmetriccomonentthereofmabecalculated

pypy

byusingtheattenuationtimeconstantofauxiliarypower

sulies.

pp

6.1.6Thesmmetricandasmmetriccomonentsofthe

yyp

feedbackcurrentofasynchronousmotorsmaybecalculatedby

usinthesameeuivalentattenuationtimeconstant.

gq

6.1.7Ifthesumofoeratintimeofrimarrotection

pgpyp

deviceandtheinherentbreakingtimeofcircuitbreakeris

，

greaterthan0.15stheeffectofasymmetriccomponentof

short-circuitcurrentonshort-circuitratinofcircuitbreaker

g

，

manotbetakenintoaccount.Howeveritshallbeconsidered

y

：

underthefollowingconditions

1Thesumofoeratintimeofrimarrotectiondevice

pgpyp

andtheinherentbreakintimeofcircuitbreakerislessthan

g

；

0.11s

2Thesumofoeratintimeofrimarrotectiondeviceand

pgpyp

theinherentbreakintimeofcircuitbreakerisbetween0.11sand

g

，

0.15sandthesymmetriccomponentofshort-circuitcurrent

accountsformorethan90%oftheratedbreakingcurrentofcircuit

breaker.

··

476.2MVElectricalEuimentSelection

qp

6.2.1MVauxiliarcircuitbreakersshouldbeofoil-free

y

，

te.For125MWoraboveunitoil-freeMVauxiliarcircuit

ypy

breakersshallbeapplied.

，

6.2.2Forunitswithunitcaacitof200MWorabovevacuum

py

circuitbreakershouldbeappliedtogetherwithMVfuse-vacuum

contactorcombination.Forauxiliarowersulcircuitsthatare

ypppy

，

startedandstoedfreuentlMVfuse-vacuumcontactor

ppqy

combinationshouldbeemployed.

，

6.2.3IndoorLVauxiliartransformersshallbeofdrte

yyyp

whileoutdoorLVauxiliarytransformersshouldbeofoil-immersed

te.

yp

6.2.4SelectionofMVfuse-vacuumcontactorcombination

：

shouldbeinaccordancewiththefollowingprinciples

1SecialMVcurrent-limitinfusesshallbealiedas

pgpp

MVfusesdependinguponcharacteristicsoftheprotected

equipment.TheMVcurrent-limitingfusesshouldnotbe

，

aliedinarallelwitheachothernorbealiedinreduced

ppppp

；

voltageapplications

2RatedbreakincurrentofMVfusesshallbereater

gg

thanthermsvalueofsymmetriccomponentofthemaximum

；

short-circuitcurrentexpectedtooccurincircuit

3MVfuse-vacuumcontactorcombinationshouldnotbe

appliedasprotectionandoperatingdeviceinfeedersforoverhead

；

lineortransformer-overheadline

4Vacuumcontactorshallbeabletowithstandandclose

；

breakingcurrentofcurrent-limitingfuse

··

485ThescoeofalicationofMVfuse-vacuumcontactor

ppp

combinationshallbereasonablydeterminedaccordingto

，

voltaeratinsofMVauxiliarowerandnatureandworkin

ggypg

currentofMVauxiliarowersulcircuits.

ypppy

6.3Short-circuitCurrentCalculationinLVAuxiliarPowerSstem

yy

6.3.1Thecalculationofshort-circuitcurrentinLVauxiliary

owersstemandselectionandcheckofelectricaleuimentand

pyqp

conductorsinLVauxiliarowersstemshallbeincomliance

ypyp

/

withDLT5222DesignTechnicalRuleforSelectingConductor

andElectricalEuiment.

qp

6.3.2Theshort-circuitcurrentof380Vpowercenterissourced

，，

fromtwoartsresectivelLVauxiliartransformersand

ppyy

asnchronousmotors.Itshallbecalculatedasthearithmeticsumof

y

short-circuitcurrentsfromthetwopartswiththesamephase

anle.

g

6.3.3Thefollowingfactorsshallbetakenintoaccountin

：

calculationofshort-circuitcurrentinLVauxiliarypowersystem

；

1Resistanceshallbetakenintoconsideration

2ThevoltageonMVsideofLVauxiliarytransformer

；

mabeconsideredasconstantdurinshort-circuitin

ygg

，

3Whenshort-circuitoccursbelowfeederofpowercenter

theimpedanceofthefeedersshallbetakenintoaccountandthe

feedbackcurrentofasnchronousmotorsmabeexcludedfrom

yy

consideration.

6.3.4Whenshort-circuitoccursin380Vowercenterormotor

p

，

controlcenterthefeedbackcurrentofthemotorsdirectl

y

connectedtodistributionpanelsshallbetakenintoaccount.Refer

··

49toAendixMforthemethodforcalculatinfeedbackcurrent.

ppg

，

6.3.5Whenshort-circuitoccursoncablelinessymmetric

comonentoftheshort-circuitcurrentmabeconsultedin

py

（）

AendixN.Iftheratioofthelenthmtosectionalarea

ppg

2

（），

mmofcableisreaterthan0.5theasmmetriccomonent

gyp

ofshort-circuitcurrentmabenelected.

yg

6.4LVElectricalEuimentSelection

qp

6.4.1Theshort-circuitratinofcircuitbreakersandfusesshall

g

：

becheckedinaccordancewiththefollowingrequirements

1Theshort-circuitowerfactorsattheinstallationlocations

p

ofcircuitbreakersandfusesshallbenolessthantheratedshort-

circuitowerfactors.

p

2Thermsvalueofsymmetriccomponentoftheexpected

short-circuitcurrentvalueattheinstallationlocationsofcircuit

breakersandfusesshallnotbereaterthanallowableshort-circuit

g

breakingrating.Ifthepowersupplyincominglinesareconnectedat

，

thelowerartofcircuitbreakertheresultinimactontheshort-

pgp

circuitbreakinratinofcircuitbreakershallbeconsidered.The

gg

short-circuitbreakingratingofcircuitbreakersshallalsomeetthe

：

followinreuirements

gq

）

1Iftheinstantaneousover-currentreleaseofcircuit

，

breakerisusedforshort-circuitprotectionthe

short-circuitbreakinratinofthecircuitbreaker

gg

；

shallbeappliedforchecking

）

2Ifthetimedelaover-currentreleaseofcircuitbreakeris

y

，

usedforshortcircuitrotectiontheshort-circuit

p

breakingratingofcircuitbreakerforthecorresponding

··

50；

timedelashallbealiedforcheckin

yppg

）

3Ifcircuitbreakerisadditionallyprovidedwithrelay

rotectionandoeratintimethereofdoesnotexceed

ppg

themaximumtimedelaofthetimedelareleaseofthe

yy

，

circuitbreakerthentheshort-circuitbreakingrating

durinthetimedelatriinshallbetheshort-circuit

gyppg

breakingratingofcircuitbreaker.Iftheoperatingtime

oftherelarotectionexceedsthemaximumtimedela

ypy

，

ofthetimedelareleasetheshort-circuitratinof

yg

circuitbreakershallbeasspecifiedbythemanufacturer.

3Theexectedshort-circuitcurrentvalueattheinstallation

p

locationreferstormsvalueofthesymmetriccomponentinone

ccleattheinstantofbreakin.