DLT 5551-2018 架空输电线路荷载规范：英文

ICS29.240

P62

RecordNumber：J2641-2019

ELECTRICPOWERINDUSTRYSTANDARDOFTHEPEOPLESREPUBLICOFCHINA

P

DL/T5551-2018

CodefortheDesignofOverhead

TransmissionLineLoading

架空输电线路荷载规范

IssuedonDecember25，2018ImplementedonMay1，2019

IssuedbytheNationalEnergyAdministrationELECTRICPOWERINDUSTRYSTANDARDOF

THEPEOPLESREPUBLICOFCHINA

CodefortheDesinofOverhead

g

TransmissionLineLoadin

g

/

DLT55512018

：

ChiefDevelomentDeartmentElectricPowerPlanninand

ppg

EngineeringInstitute

：

ArovalDeartmentNationalEnerAdministration

pppgy

：，

ImplementationDateMay12019

ChinaPlanninPress

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Beiin2024

jgChineseeditionfirstpublishedinthePeoplesRepublicofChinain2019

EnlisheditionfirstublishedinthePeolesReublicofChinain2024

gppp

bChinaPlanninPress

yg

th

，，

4FloorCTowerGuohonBuildin

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，，

No.A11Muxidi-BeiliXichenDistrict

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，

Beijing100038

jp

PrintedinChinabyPrintedinChinabyBeijinghouchengzeming

，

PrintinTechnoloCo.Ltd

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Ⓒ2019byNationalEnergyAdministration

Allrihtsreserved.Noartofthisublicationmabereroducedor

gppyp

，，，，

transmittedinanformorbanmeansrahicelectronicormechanical

yyygp

，，

includingphotocopyingrecordingoranyinformationstorageand

，

retrievalsstemswithoutwrittenermissionoftheublisher.

ypp

，

Thisbookissoldsubjecttotheconditionthatitshallnotbywayof

，，，

tradeorotherwisebelentresoldhiredoutorotherwisecirculated

withouttheublishersriorconsentinanformofblindinorcover

ppyg

otherthanthatinwhichthisispublishedandwithoutasimilarcondition

includingthisconditionbeingimposedonthesubsequentpurchaser.

ISBN978-7-5182-1732-8Introduction

，

ThisEnglishversionwhosetranslationwasorganizedby

，

ChinaElectricPowerPlannin&EnineerinInstituteCo.Ltd.

ggg

asauthorizedbNationalEnerAdministrationincomliance

ygyp

，

withrelevantproceduresandstipulationsisoneofChinasenergy

industrystandardsinEnglishseries.ThisEnglishversionwas

ublishedbNationalEnerAdministrationofthePeoles

pygyp

〔〕，，

ReublicofChinainAnnouncement2023No.2datedMa

py

2024.

TheEnlishversionwastranslatedfromtheChinese

g

StandardLoadCodeortheDesinoOverheadTransmissionLine

fgf

/

DLT55512018.

ThecorihtisownedbNationalEnerAdministration.

pygygy

，

Intheeventofandiscreancintherocessofimlementation

ypypp

theChineseversionshallprevail.

Manythankswouldgotothestafffromrelevantstandard

develomentoranizationsandthosewhohaverovided

pgp

enerousassistanceinthetranslationandreviewrocess.

gp

，

ForfurtherimprovementoftheEnglishversionallcomments

：

andsuestionsarewelcomeandshouldbeaddressedtoChina

gg

ElectricPowerPlanninandEnineerinInstitute.No.65

ggg

，，，：

AnderoadXichengDistrictBeijing100120China.Website

www.e.

pp

··

1：

Translatinoranizations

gg

，

EastChinaElectricPowerDesinInstituteCo.Ltd.of

g

，

ChinaPowerEngineeringConsultingGroupChinaElectric

PowerPlanninandEnineerinInstitute.

ggg

：

Translatingstaffs

，

EastChinaElectricPowerDesinInstituteCo.Ltd.of

g

：，

ChinaPowerEnineerinConsultinGrouXUEChunlin

gggp

，，，，

ZHAOZhengYUANZhileiWENZuomingFUPengcheng

，

ZHANGYinWANGYimin

ChinaElectricPowerPlanningandEngineeringInstitute

，：，，

Co.Ltd.YINPenYANGJinboDONGFeifei

gg

：

Reviewanelstaffs

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LIYongshuangChinaElectricPowerPlanningand

EnineerinInstitute

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LIXilaiChinaElectricPowerPlanningand

EnineerinInstitute

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LIAOZonaoChinaElectricPowerPlanninand

ggg

EngineeringInstitute

WANGHuchanChinaElectricPowerPlanninand

gg

EngineeringInstitute

HUANGChunChinaElectricPowerPlanninand

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EnineerinInstitute

gg

YANGLidongNortheastElectricPowerDesign

，

InstituteCo.Ltd.ofChinaPower

EngineeringConsultingGroup

WUGaoboCentralSouthernChinaElectric

，

PowerDesinInstituteCo.Ltd.of

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ChinaPowerEngineeringConsulting

··

2Grou

p

TANHaowenNorthwestElectricPowerDesin

g

，

InstituteCo.Ltd.ofChinaPower

EnineerinConsultinGrou

gggp

，

SHIJinhuaNorthChinaPowerEnineeriCo.

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Ltd.ofChinaPowerEngineering

ConsultinGrou

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DANHanboChinaEnerEnineerinGrou

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ZhejiangElectricPowerDesign

，

InstituteCo.Ltd.

YANGFenliChinaElectricPowerResearch

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，

InstituteCo.Ltd.

··

3翻译出版说明

本译本为国家能源局委托电力规划设计总院按照有关程序

，。

和规定统一组织翻译的能源行业标准英文版系列译本之一

，。

年月日国家能源局以年第号公告予以公布

202452420242

本译本是根据中国电力出版社出版的《架空输电线路荷载规

范》/翻译的，著作权归国家能源局所有。在使

DLT55512018

用过程中，如出现异议，以中文版为准。

本译本在翻译和审核过程中，本标准编制单位及编制组有关

。

成员给予了积极协助

为不断提高本译本的质量，欢迎使用者提出意见和建议，并

反馈给电力规划设计总院。

地址：北京市西城区安德路号

65

邮编：

100120

：

网址

：

本译本翻译单位

中国电力工程顾问集团华东电力设计院有限公司、电力规划

总院有限公司

本译本翻译人员：

中国电力工程顾问集团华东电力设计院有限公司：薛春林、

、、、、、。

赵峥袁志磊温作铭傅鹏程张颖王懿敏

电力规划总院有限公司：尹鹏、杨靖波、董飞飞。

本译本审核人员：

李永双电力规划设计总院

李喜来电力规划设计总院

··

1廖宗高电力规划设计总院

王虎长电力规划设计总院

黄淳电力规划设计总院

杨礼东中国电力工程顾问集团东北电力设计院有限公司

吴高波中国电力工程顾问集团中南电力设计院有限公司

谭浩文中国电力工程顾问集团西北电力设计院有限公司

施菁华中国电力工程顾问集团华北电力设计院有限公司

但汉波中国能源建设集团浙江省电力设计院有限公司

杨风利中国电力科学研究院有限公司

··

2NationalEnerAdministration

gy

Announcement

〔〕

2018No.16

Accordingtothe＂NoticeofNationalEnergyAdministration

onPrintinandDistributintheReulationsofEnerIndastr

ggggyy

（）

StandardizationTrialVersionandImlementationRules＂

p

（〔〕），

GNJKJ2009No.52theNationalEnergyAdministration

（

hasapproved204industrialstandardssuchasCodeor

f

EnineerinGeoloicalInvestiationoPhotovoltaicPower

ggggf

），（

ProectsConsistinof32enerstandardsindicatedb

jggyy

），（）

NB172electricpowerstandardsindicatedbyDL.Theyare

herebreleased.

y

：

AendixListofrofessionalstandards

ppp

NationalEnergyAdministration

，

December252018

··

1：

Aendix

pp

Listofprofessionalstandards

StandardStandardRelacedReferenceArovalImlementation

pppp

No.

codeNo.namestandardstandardNo.datedate

…

LoadCode

/

DLTfortheDesign

1922018-12-252019-05-01

55512018ofOverhead

TransmissionLine

…

··

2Foreword

〔〕

AccordingtotherequirementsofDocumentGNKJ2014

，

No.298issuedbNationalEnerAdministration＂Noticeon

ygy

ReleasingtheDevelopingandRevisingPlanoftheFirstBatch

，

ofEnerIndustrStandards＂.Durintherevisiontheanelhas

gyygp

，

conductedextensiveinvestiationsandstudiessummeduthe

gp

，

praticalexperienceinthefieldofoverheadtransmissionlineload

comrehensivelandsstematicallcombinandinteratin

pyyyggg

matureprovisionsofcurrentdomestictransmissionline

，

standardsmadereferencetorelevantstandardsbothathome

，

andabroadandcollectedcommentswidelfrominterests

y

concerned.

，

Thiscodeconsistsof10chatersand3aendixeswith

ppp

：，

themaincontentsasfollowsgeneralprovisionstermsand

，，

smbolsmeteoroloicalconditionsclassificationandcombination

yg

，，，，，

ofloadsermanentloadwindloadiceloadwiretension

p

，，

constructionandmaintenanceloadsandaccidentalLoadsetc.

ThiscodeisadministeredbtheNationalEner

ygy

，

AdministrationproposedbyChinaElectricPowerPlanning

，

andEnineerinInstituteroutinelmanaedbPower

ggygy

GenerationDesinStandardizationTechnicalCommitteeofthe

g

energyindustry.EastChinaElectricPowerDesignInstitute

，

Co.Ltd.ofChinaPowerEnineerinConsultinGrouis

gggp

responsiblefortheinterpretationofspecifictechnicalcontents

··

1herein.Ancommentsandsuestionsraiseddurinthe

yggg

imlementationofthiscodearetobereferredtotheElectric

p

，

PowerPlanningandEngineeringInstituteatNo.65Ande

，，，，

RoadXichenDistrictBeiinP.R.China100120.

gjg

，

Chiefdevelopmentorganizationparticipatingdevelopment

，

oranizationschiefdraftinstaffsandchiefreviewinstaffsof

ggg

：

thiscode

：

Chiefdevelomentoranization

pg

，

EastChinaElectricPowerDesinInstituteCo.Ltd.

g

ofChinaPowerEngineeringConsultingGroup

：

Particiatindevelomentoranizations

pgpg

ChinaElectricPowerPlanninandEnineerin

ggg

Institute

，

SouthwestElectricPowerDesinInstituteCo.Ltd.

g

ofChinaPowerEngineeringConsultingGroup

ChinaEnerEnineerinGrouGuandon

gyggpgg

，

ElectricPowerDesinInstituteCo.Ltd.

g

StateNuclearElectricPowerPlanningDesignand

，

ResearchInstituteCo.Ltd.

ChinaEnergyEngineeringGroupShanxiElectric

，

PowerConstructionCo.Ltd.

POWERCHINAGuizhouElectricPowerEnineerin

gg

，

Co.Ltd.

：

Chiefdraftinstaffs

g

XUEChunlinZHAOZhengZHANGDonghong

YINPengXIAOHongweiDUANChengyin

YUANZhileiJINXiaohuaLIShifen

g

YANTaoTANGJianXIABoRENZongdong

··

2XIAOLiunFUPenchenLIANGMin

qggg

HUANGXinZHUYinieMOZhenlu

ggjg

ZHAOHuyuanYANGJingboZHAOXueling

HEJianWANGZiinHEYunxian

gjg

LUODonlianXUXinWANGRui

ggg

DAIZhiqiangZHURuiyuanYUDengke

DONGFeifeiZHANGLonWENZuomin

gg

ZHANGXini

q

：

Chiefreviewers

LIXilaiMARenleLIYongshuangWANGJin

DUANSontaoLIAOZonaoZHAOJiantao

gggg

LIJinCHENJieDENGHonzhouFANWenlian

gg

HOUZhongweiWANGYongYANGLin

WANGHuchanZHAOQinbinBAOYonzhon

gggg

ZHUYoninZHAOQuanianYANGLi

gpgjg

LIZhiZHANGJianLUJingxingWANGZhiqiang

SHIJinhuaLIUHanshenDUANRanHEJian

gg

GUOYonSHIFan

gg

··

3Contents

…………………（）

1GeneralProvisions1

…………………（）

2TermsandSymbols2

（）

………………

2.1Terms2

（）

……………

2.2Smbols6

y

（）

……………

3MeteoroloicalCondition10

g

…………（）

4ClassificationandCombinationofLoads16

4.1ClassificationofLoadsandRepresentativeValueof

………………（）

Loads16

（）

…………………

4.2CombinationofLoads17

（）

……

5PermanentLoads29

…………（）

6WindLoads30

……………（）

6.1WindLoadsonConductorsandEarthwires30

………………（）

6.2WindLoadsonSupports34

………（）

6.3WindLoadsonInsulatorStrings38

……………（）

7IceLoads40

（）

…………

8WireTension41

（）

………………

9ConstructionandMaintenanceLoads44

（）

……

10AccidentalLoads47

AendixADescritionofTicalMeteoroloical

pppypg

……（）

District49

……………（）

AppendixBTableofLoadCombinations50

··

1AendixCLoadinfortheEffectofCurved

ppg

（）

……

Tower53

（）

…

ExlanationofWordininthisCode57

pg

………………（）

ListofQuotedStandards58

··

21GeneralProvisions

1.0.1Thiscodeisformulatedwithaviewtoimplementing

，

thenationalcaitalconstructionolicaswellastechnicaland

ppy

，

economicolicinthedesinofoverheadtransmissionlineandto

pyg

，，

ensuringsafetyandreliabilityadvancedusabilityeconomyand

，

rationalityresourceconservationandenvironmentalfriendliness.

1.0.2Thiscodeisalicabletothedesinof110kVandabove

ppg

overheadtransmissionlineandlarecrossininthelihticin

gggg

areas.

1.0.3Aroriatestrentheninmeasuresshouldbetaken

pppgg

forimortantlinesandseciallinesectionsforhihersecurit

ppgy

performance.

1.0.4Overheadtransmissionlineloadinshallconformto

g

therovisionsofthiscodeaswellastherovisionsofthe

pp

currentrelevantnationalstandards.

··

12TermsandSmbols

y

2.1Terms

2.1.1Overheadtransmissionline

Anelectriclinewhoseconductorsaresupportedabove

，

roundenerallbmeansofinsulatorsandaroriate

ggyyppp

suorts.

pp

2.1.2Largecrossing

，

Atensionsectionoflinescrossinwidenaviablerivers

gg

（）

lakesorstraitswithlongspanlengthabove1000morhigh

（），

towershiherthan100mwheresecialconsiderationshallbe

gp

iventoconductorselectionorsuortdesinandafailurema

gppgy

affectnavigationseverelyorbeextremelydifficulttorepair.

2.1.3Ultra-hihvoltaeoverheadtransmissionline

gg

Anoverheadtransmissionlinewithanominalvoltageof

，

1000kV±800kVandabove.

2.1.4Referencewindseed

p

Windspeedcorrespondingtoanaveragingperiodof

，，，

10minhavinareturneriodof3050or100earsand

gpy

determinedthroughprobabilitystatisticsaccordingtothe

observationdataofmaximumwindseedat10mheihton

pg

（

localoenandflatroundtheaveraeminimumwaterlevelin

pgg

）

windyseasonsovertheyearsshallbetakenforlargecrossing.

2.1.5Desinicethickness

g

3

/

Icethicknessconvertedintodensityof0.9gcmwitha

··

2returneriodsecifiedinthedesin.

ppg

，

2.1.6Rarewindseedrareicethickness

p

，

Severewindoriceeventswhichdidoccuraccordingto

historicalrecordsandsinificantlexceededthefreuenc

gyqy

curvesrecordedovertheyears.

//

2.1.7Lihtmediumheavicinarea

gyg

Alihticinareaisanareawithdesinicethicknessof

ggg

，

10mmandbelowamediumicingareawithdesignice

，

thicknesslarerthan10mmbutnotlarerthan20mmanda

gg

heavyicingareawithdesignicethicknessof20mmandabove.

2.1.8Permanentload

Loadwhichislikeltoberesentthrouhouttheservice

ypg

，

periodofoverheadtransmissionlineandforwhichthevariationin

，

manitudewithtimeisneliibleinrelationtothemeanvalueor

ggg

（）

forwhichthevariationisalwaysinthesamedirectionmonotonic

untiltheactionattainsacertainlimitvalue.

2.1.9Variableload

Loadwhichisvariablewithtimeintheserviceperiodof

，

structuresandforwhichthevariationinmanitudeisnot

g

negligibleinrelationtothemeanvalue.

2.1.10Accidentalload

，，

Loadusuallofshortdurationwhichisunlikeltooccur

yy

withasignificantmagnitudeduringthedesignworkinglife.

2.1.11Earthuakeaction

q

，

Structuredynamicactionduetoearthquakeincluding

horizontalseismicactionandverticalseismicaction.

2.1.12Reresentativevalueofload

p

，

Loadvalueadoptedinthedesigntocheckthelimitstate

··

3，，

e..characteristicvaluecombinationvalueetc.

g

/

2.1.13Characteristicvaluenominalvalue

，

Fundamentalrepresentativevalueofloadwhichdenotes

thecharacteristicvalueforthestatisticaldistributionofthe

（，

maximumloadinthedesignreferenceperiode.g.meanvalue

，，）

modemid-valuecertainfractile.

2.1.14Combinationvalue

，

Representativevalueofvariableloadforwhichthe

exceedinrobabilitforthecombinedloadeffectindesin

gpyg

referenceperiodtendstobeconsistentwiththecorresponding

，

robabilitwhilethevariableloadaearsaloneorforwhich

pypp

thestructuredesinedaccordintotheloadcombinationhasa

gg

uniformlyspecifiedreliabilityindex.

2.1.15Seismicfortificationintensit

y

，

Seismicintensityapprovedbystateauthoritytakenasthe

，

basisforseismicfortificationinacertainreionandsecified

gp

withanexceedinrobabilitof10%within50earsunder

gpyy

normalcircumstance.

2.1.16Limitstate

Aconditionbeyondwhichthestructureorapartofthe

structurenolonersatisfiesthedesinerformancereuirements.

ggpq

2.1.17Ultimatelimitstate

，

Stateassociatedwithcollapseorwithotherformsof

，，

structuralfailureduetoexcessivedeformationlossofstabilit

y

，，，

overturningrupturebucklingetc.

2.1.18Serviceabilitylimitstate

Statebeondwhichsecifiedserviceordurabilitcriteria

ypy

forstructureorstructuralelementisnolongermet.

··

42.1.19Desinvalueofload

g

Productofreresentativevalueofloadandartialfactor.

pp

2.1.20Loadeffect

Resonseofstructureorstructuralelementbalied

pypp

，，，

ernalforcedeformationcrack.

2.1.21Loadcombination

Setofdesinvaluesofsimultaneousloadsusedforthe

g

verificationofthestructuralreliabilityforalimitstate.

2.1.22Fundamentalcombination

Combinationofpermanentloadandvariableloadforthe

ultimatelimitstate.

2.1.23Accidentalcombination

，

Combinationofpermanentloadvariableloadandan

，

accidentalloadfortheultimatelimitstateorcombinationof

permanentloadandvariableloadforoverallstabilitycheckafter

accidentalevents.

/

2.1.24Characteristicnominalcombination

Combinationofcharacteristicvaluesorcombinationvaluesfor

theserviceabilitlimitstate.

y

2.1.25Referencewindpressure

WindressureobtainedwithBernoullisPrincialaccordinto

ppg

referencewindseed.

p

2.1.26Terrainroughness

Gradefordistributionconditionoftheirreularobstacles

g

，

onthegroundwithin2kmwherewindblowsoverbefore

reachingthestructure.

2.1.27Dnamicfactor

y

Equivalentfactoradoptedinstaticdesignforstructureor

··

5，

structueelementsubecttodnamicloadandthevalueof

jy

whichistheratioofthemaximumdnamiceffectandthe

y

correspondingstaticeffect.

2.2Smbols

y

：

2.2.1Representativevalueofloadandloadcombination

—；

Acharacteristicvalueofaccidentalload

d

—

Cspecifiedlimitvaluesatisfyingserviceabilityrequirements

；

ofstructureorstructuralelement

—；

Gcharacteristicvalueofermanentload

kp

—；

Qkcharacteristicvalueofvariableload

—

Rdesinvalueofresistanceofstructureorstructural

dg

；

element

—；

SAdcharacteristicvalueofaccidentalloadeffect

—；

Sdesinvalueofeffectofloadcombination

dg

—

SEhkcharacteristicvalueoftheeffectofhorizontalearthquake

；

action

—

Scharacteristicvalueoftheeffectofverticalearthuake

Evkq

；

action

—

Sreresentativevalueofermanentloadeffectforseismic

GEpp

；

fundamentalcombination

—；

SGkcharacteristicvalueofpermanentloadeffect

—；

Sreresentativevalueofithvariableloadeffect

QiRp

—

STRrepresentativevalueoftheeffectofconductorand

；

earthwiretension

—；

Scharacteristicvalueofwindloadeffect

wk

—；

γ0importancefactorforstructure

，—

γγartialfactorforhorizontalandverticalearthuake

EhEvpq

··

6；

actionresectivel

py

—；

γartialfactorforermanentload

Gpp

—；

γartialfactorforvariableload

Qp

—

γseismicadustmentfactorforload-carrincaacit

REjygpy

；

ofmember

—

γartialfactorforconductorandearthwiretensionin

ETp

；

seismicfundamentalcombination

—；

adjustmentfactorforvariableload

ψ

—

combinationvaluefactorforwindloadinseismic

wE

ψ

fundamentalcombination.

：

2.2.2Windload

—；

Awindressureareaofasinleinsulatorstrin

Ipgg

—；

ASprojectedareaofwindwardmember

—

Bamlificationfactorforwindloadonice-covered

1p

；

conductorsandearthwires

—

Bamlificationfactorforwindloadonice-covered

2p

；

suortmembers

pp

—

B3amplificationfactorforwindloadonice-covered

；

insulatorstrins

g

—；

Bbackroundfactor

Zg

—，

douterdiameterofconductororearthwireortheir

；

calculatindiameterwhencoatedwithice

g

—；

f1first-ordervibrationnaturalfrequencyofstructure

—；

eakfactororravitationalacceleration

gpg

—；

Inominalturbulenceintensitat10mheiht

10yg

—

IZturbulenceintensityattheaverageheightofzfor

；

conductorsandearthwires

—

—

Iturbulenceintensitdistributionfunctionalonthe

Zyg

··

7；

heiht

g

—；

Lwindsan

Pp

—；

Lintegralscaleforhorizontalcorrelationfunction

X

—

nnumberofinsulatorstrinsroectedonalane

gpjp

；

perpendiculartowinddirection

—；

Rresonancefactor

—；

Vreferencewindseed

0p

—；

W0referencewindpressure

—；

Wcharacteristicvalueofwindloadoninsulatorstrins

Ig

—；

WScharacteristicvalueofwindloadonsupports

—

Wcharacteristicvalueofhorizontalwindloaderendicular

Xpp

；

toconductorsorearthwires

—，

zaverageheightofconductororearthwireheightofa

；

suortsectionaboveround

ppg

—；

αterrainrouhnessindex

g

—；

αLspanfactor

—；

ustresonsefactorforconductorandearthwire

Cgp

β

—；

ustresonsefactorataheihtofz

Zgpg

β

—

γreductionfactorforwindloadonconductorsand

C

；

earthwires

—；

δLintegrationfactorforcorrelationofspanlength

—

εreductionfactorforfluctuationofwindloadonconductors

c

；

andearthwires

—；

εtreductionfactorforfluctuationofwindloadonsupports

—

reductionfactorforwindloadonleewardfaceof

η

；

latticetower

—；

1factorforthefirst-ordervibrationmodeofstructure

φ

—

λwindwardshelterinreductionfactorforwindload

Ig

··

8；

oninsulatorstrins

g

—；

drafactorforastructuralelement

g

μS

—；

SCdragfactorforconductororearthwire

μ

—；

drafactorforinsulatorstrin

SIgg

μ

—；

exosurefactorforwindressure

Zpp

μ

—

θincludedanglebetweenwinddirectionandconductorsor

；

earthwires

—

first-ordermodedaminratioofsteelsuort.

1pgpp

ζ

：

2.2.3Iceload

—；

cdesignicethickness

—；

douterdiameterofearthwireorasinleconductor

1g

—；

Icharacteristicvalueoficeload

k

—；

LVweightspanfordesignicingcondition

—；

nnumberofsub-conductor

S

—

densitofice.

Iy

ρ

：

2.2.4Accidentalload

—

Aareaoftheustreamfaceoffoundationwithconsideration

p

；

ofeneralscour

g

—

Fcharacteristicvalueofimpactforceofdriftingobjects

；

actingattheelevationofwaterlevel

—；

Fcharacteristicvalueoftheressureofwatercurren

wp

—；

Kdrafactorforfoundationier

gp

—；

mmassofdriftingobject

—；

Timacttime

p

—；

Vvelocitofwatercurrent

wy

—

wdensityofwater.

ρ

··

93MeteoroloicalCondition

g

3.0.1Thedesignmeteorologicalconditionofoverhead

transmissionlineshallbedeterminedaccordintothestatistical

g

meteorologicaldataalongtherouteandtheserviceexperiences

ofexistinlinesnearb.Ifthemeteoroloicalconditionsalon

gygg

theroutearesimilartotheticalconditionsiveninAendix

ypgpp

，

Athelistedtypicaldatashouldbeused.

3.0.2Thereturneriodofreferencewindseedanddesin

ppg

：

icethicknessshallbeinaccordancewiththefollowingrequirements

，

11000kV±800andabovetransmissionlinesandlare

g

：

crossins100ears.

gy

、

2500kV750kV±500kV±600kVtransmissionlines

：

andlarecrossins50ears.

ggy

：

3110kV330kVtransmissionlinesandlargecrossings

30ears.

y

4Thereturneriodshallbedeterminedaccordintothe

pg

highestvoltagelevelforlineswithvariousvoltagelevels.

3.0.3Themaximumannualwindseedwithanaverain

pgg

periodof10minfromthelocalmeteorologicalobservatory

shallbeusedasthesamletodeterminethereferencewind

p

，

seed.Inadditiontheextremevaluet