DLT 252012 ±800kV直流架空輸電線路檢修規(guī)程

ICS27.100

F23

Recordnumber:36421-2012

ElectricPowerIndustryStandardofthe

People’sRepublicofChina

DL/T251—2012

MaintenanceCodefor±800kVDCOverheadTransmissionLine

±800kV直流架空輸電線路檢修規(guī)程

(EnglishTranslation)

Issuedate:2012-04-06Implementationdate:2012-07-01

IssuedbyNationalEnergyAdministration

Foreword

DL/TC12isinchargeofthisEnglishtranslation.IncaseofanydoubtaboutthecontentsofEnglishtranslation,

theChineseoriginalshallbeconsideredauthoritative.

ThisstandardwasproposedbyChinaElectricityCouncil.

ThisstandardwaspreparedbytheTechnicalCommitteeforStandardizationofHVDCTransmissionTechnology

inthePowerIndustry(DL/TC12).

PleasesendanyopinionsorsuggestionsputforwardduringtheexecutionofthisstandardtotheStandardization

ManagementCenterofChinaElectricityCouncil(No.1,Lane2,BaiguangRoad,Beijing,100761).

TranslationunitofEnglishversionofthisstandard:StateGridInternationalDevelopmentCo.,Ltd.

Maintranslatorsandeditorsofthisstandard:SunXiaolong，LiQiongjiu,GuoXuejian.

I

MaintenanceCodefor±800kVDCOverheadTransmission

Line

1Scope

1.1

Thiscodespecifiesthemaintenanceitems,content,andcycle,etc.of±800kVDCoverheadtransmissionlines.

1.2

Thiscodeisapplicableto±800kVDCoverheadtransmissionlines,auxiliarygroundingpolesandlines.

2NormativeReferences

Thefollowingreferenceddocumentsareindispensablefortheapplicationofthisdocument.Fordatedreferences,

onlytheeditioncitedapplies.Forundatedreferences,thelatesteditionofthereferenceddocument(includingany

amendments)applies.

GBJ50233Codeforconstructionandacceptanceof110~500kVoverheadtransmissionline

DL409Safetycodeofelectricpowerindustry(powerlines)

DL/T436Technicalguidelinesforhighvoltagedirectcurrentoverheadtransmissionlines

DL/T437Technicalguidelinesforhighvoltagedirectcurrentgroundingpoles

DL/T627Roomtemperaturevulcanizedsiliconrubberanti-pollutionflashovercoatingforinsulators

DL/T683Nomenclatureforfittingsmodel

DL/T741Operationregulationsforoverheadtransmissionlines

DL/T763Technicalrequirementsforpre-twistedfittingsforoverheadlines

DL/T881Technicalguideforliveworkingin±500kVDCtransmissionline

DL/T1069Guidelinesforrepairinggroundwiresofoverheadtransmissionlines

DL/T5092Technicalspecificationfordesignof110~500kVoverheadtransmissionline

DL/T5235Codeforconstructionandacceptanceof±800kVandunderDCoverheadtransmissionline

SDJ226Specificationforhydraulicconstructionprocessofoverheadtransmissionlineconductorand

lightningconductorprotectionline

3BasicRequirements

3.1

Theproductionmanagementdepartmentaswellastheoperationmaintenanceandoverhauldepartmentmust

strengthenthemanagementofequipmentoverhaul,earnestlycarryouttheoverhaulofequipment,andkeepthe

powertransmissionequipmentinasoundstate.

3.2

Equipmentmaintenanceinvolvesboth“inspectionandrepair”.Maintenanceshalladheretotheprinciplethat“the

equipmentwhichshallberepairedmustberepairedsufficiently”,analyze,concludeandsummarizetheequipment

defectsandallkindsofabnormalitiesfoundbyinspection,detectionandonlinemonitoringdevices.

3.3

Equipmentmaintenanceshalladoptliveworkingasfaraspossibletoreducetheequipmentmaintenanceoutage.

4

3.4

ThemaintenanceoperationmustbecarriedoutinaccordancewiththeprovisionsofDL409,andtheorganizational,

technicalandsafetymeasuresshallbeimplementedsufficiently.Theworkticketsystem,workpermitsystem,work

interruptionsystem,workguardianshipsystem,workterminationandpowerrecoverysystemshallbeexecutedina

strictmanner.

3.5

Equipmentmaintenanceshallactivelyapplyadvancedmaterials,processes,methodsandmaintenancetoolsand

instruments,andstrivetoimprovethequalityofmaintenance,shortenthemaintenanceperiod,ensurethesafetyof

maintenance,soastoprolongtheservicelifeofequipmentandimprovethesafeoperationlevel.

3.6

Themaintenancetoolsandinstrumentsmustbequalifiedproductsandusedwithinthevalidityperiodofinspection.

Theuse,storage,inspectionandtestofthetoolsandinstrumentsshallcomplywiththerequirementsofDL409.

3.7

Afterequipmentmaintenanceandemergencyrepair,ifthemodel,quantityandothertechnicalparametersofthe

equipmentarechanged,thetechnicalfilesofthecorrespondingequipmentshallbechangedintime.Itstechnical

datamanagementshallconformtothecorrespondingprovisionsinDL/T741.

3.8

Forpreventionandmaintenanceofspecialsections(specialsectionreferstothebig-spanlinesandthoselocatedin

heavily-pollutedarea,heavy-icearea,thunderstorm-pronearea,flooderosionarea,unfavorablegeologicalarea,

miningsubsidencearea,theft-pronearea,wire-gallopingarea,areavulnerabletoexternalforcedamage,

micro-climatearea,bird-strikearea,areaspanningwoodsorbamboogrove,anddenselypopulatedareas,etc.),

correspondingmeasuresshallbetakenintermsofmaintenancematerials,toolsandtechnologyaccordingtothe

characteristicsofthesectionwherethelineislocated.

3.9

Theoperationandmaintenancedepartmentshalldeterminetheplannedmaintenanceitemsaccordingtothephysical

statusoflineequipment,inspection,anddetectionresults,maintenancecycleandDL/T436requirements,andmake

quarterlyandmonthlymaintenanceplansaccordingtotheannualmaintenanceplanissuedbythesuperior,

conscientiouslymakepreparationsformaintenance,andstrictlyimplementthemaintenanceaccordingtotheplan.

3.10

Themaintenanceoftheequipmentshallbeconductedinaccordancewithstandardizedmanagementregulations

completewithmaintenanceitem,andtheoperationinstructionsthatconformtotheactualsituationandare

practicallyoperableshallbeprepared,studiedandobservedbythemaintenancepersonnelcarefully.

3.11

Thecomplexmaintenanceitemsshallbeinvestigatedbyworkticketsignerandresponsiblepersononsiteaccording

tothemaintenancecontent.Theon-siteinvestigationshallinspecttheequipmentcondition,operationenvironment,

dangerpoint,hazardsourceandcrossingsituationofthemaintenancesite,etc.,whichshallbedocumentedwell.

3.12

Forlarge,complexanddifficultmaintenanceitems,themaintenanceplanshallbepreparedandapprovedbythe

competentleader.

3.13

5

Personnelengagedinmaintenanceoperationsmustbehealthyphysicallyandmentally,toensurethemaintenance

itemcanbecompletedinasafeandsmoothmanner.

3.14

Priortomaintenanceonthepower-cutline,verifywhetherthelineislive.Afterconfirmingthepowerofthelineis

cut,thededicatedgroundwireof±800kVDCoverheadlineshallbeconnectedtothetowersatbothendsofthe

workingsection.Forworkingonaninsulatedoverheadgroundwire,thepersonalsecurityropesmustbehungto

preventinductiveelectricitybeforeworking.

3.15

Duringtheinterruptionmaintenance,theworkshouldbestoppedincaseofsevereweathersuchasthunder,rainor

galegreaterthanLevel5.

3.16

Forgroundpotentialworkonlivetowers,operatorsmustwearqualifiedelectrostaticprotectiveclothing(orscreen

clothes)ofthecorrespondingvoltagelevel.Forequipotentialworkonlivewire,theoperatormustwearqualified

screenclothesofcorrespondingvoltagegrade.

3.17

LiveworkshallbecarriedoutingoodweatherinaccordancewithDL409,DL/T881.Stopworkingincaseof

lightningorairhumiditygreaterthan70%.IntheeventgalegreaterthanLevel4,liveworkingshouldbestopped

too.

3.18

Attheendofrelevantmaintenanceitems,qualityinspectionmustbecarriedoutaccordingtotheprovisionsofDL/T

5235,andtheoperationcannotberesumeduntilitpassestheinspection.

4GroundWire(includingOPGW)

4.1GeneralRequirements

4.1.1

Groundwiresofdifferentmaterials,specificationsandtwisteddirectionsarestrictlyprohibitedtobeconnectedin

onetensioningsection.

4.1.2

Allkindsofgroundwireshallberepairedwithdifferentrepairmaterialsaccordingtothedegreeofdamage.Forthe

repairmethodandprocess,refertoDL/T1069.Allkindsofgroundwireshallmeettherelevantrequirementsof

electricalandmechanicalcharacteristicsafterrepair.

4.1.3

Ifthedamageofsingle-strandaluminumandaluminumalloywirereaches1/2ormoreofdiameter,itshallbe

regardedasbrokenstrand.

4.1.4

Nomorethanoneslicingsleeveandtworepairsleevesshallbeinstalledoneachgroundwirewithinonepitchafter

thegroundwireisrepaired.Thefollowingrequirementsshallbemetwhentensionisreleasedandgroundwireis

repaired:

4.1.4.1

Thedistancebetweenslicingsleeveorrepairsleeveandtensionwireclampshallnotbelessthan15m;

6

4.1.4.2

Thedistancebetweentheslicingsleeveorrepairsleeveandthesuspensionclampshallnotbelessthan5m;

4.1.4.3

Thedistancebetweenslicingsleeveorrepairsleeveandspacershallnotbelessthan0.5m;

4.1.4.4

Thedistancebetweenslicingsleeveandrepairsleeveshallnotbelessthan15m.

4.1.5

Toreplacethegroundwireoradjustsag,thestressshallbecalculated,andthetoolsandequipmentshallbecorrectly

selectedaccordingtothemodelofthegroundwireandthetractiontension.Aftersagadjustment,thegroundwire

shallmeettherequirementsofDL/T5235.

4.2Maintenanceitemofgroundwire(includingOPGW)

4.2.1Openthewireclampforinspection

4.2.1.1

Intheeventoflightningdamage,pollutionflashover,icecoveringofgroundwireandgallopingofgroundwireon

theline,thegroundwireclamp(suspensionclamp,spacer,etc.)intheabnormalsectionshallbeinspected

particularlyintime.

4.2.1.2

Whenthelinerunsunderheavyloadforalongtime,thewireclampshallbeopenedforspotcheckaccordingtothe

monitoringresults.

4.2.1.3

Thewireclampshallbeopenedforinspection(keyforspotcheck)every5years.Incaseofhugeheightdifference

orload,thewireclampshallbeopenedforinspection(keyforspotcheck)accordingtotheoperationcondition.

4.2.2Polishing

Iftheouteraluminumstrandofthewirehasslightabrasion,andthedamagedepthatthesameplaceislessthan1/4

ofthediameterofthesinglestrand,andthedamageofthecross-sectionalareaisnotgreaterthan2%ofthe

cross-sectionalareaoftheconductivepart,repairisnotrequired,andonlytheedgesandburrsofthedamagedpart

arepolishedwith0#sandpaper.

4.2.3Monofilamentwindingtreatment

4.2.3.1Incaseofthefollowingcircumstancesthatthedamageofthebrokenstrandofthegroundwirehas

reducedthecross-sectionalarea,singlewirewindingtreatmentshallbecarriedout.

a)Thedamagedcross-sectionalareaofaluminumstrandofaluminumcablesteelreinforcedisnotgreaterthan7%

ofthetotalcross-sectionalareaofaluminumstrand;thedamagedcross-sectionalareaofaluminumalloystrandsof

aluminumalloyconductorsteelreinforcedisnotgreaterthan7%ofthetotalcross-sectionalareaofaluminumalloy

strands;

b)Thedamagedcross-sectionalareaofaluminumstrandedwireandaluminumalloystrandedwireisnotgreater

than7%ofthetotalcross-sectionalarea;

c)1of19strandsofgalvanizedsteelstrandisbroken.

4.2.3.2Thetreatmentmethodofmonofilamentwindingisasfollows:

a)Smooththedamagedstrand;

b)Thewindingmaterialofthegroundwireshallbeadaptedtothematerialoftherepairedgroundwire,tightly

7

wound,andfullycoverthedamagedpart.Thelengthofonesidefromtheedgeofthedamagedpartshallnotbeless

than50mm.

4.2.4Repairpre-twistedwireorrepairsleevetreatment

4.2.4.1Inthefollowingcasesthatthecross-sectionalareaofgroundwireisreducedduetobrokenstrand,repair

pre-twistedwireorrepairsleeve.

a)Thedamagedcross-sectionalareaofaluminumstrandofaluminumcablesteelreinforcedis7%-25%ofthetotal

cross-sectionalareaofaluminumstrand,andthatofaluminumcablesteelreinforcedis7%-25%ofthetotal

cross-sectionalareaofaluminumstrand;

b)Thedamagedcross-sectionalareaofaluminumstrandedwireandaluminumalloystrandedwireis7%-17%of

thetotalcross-sectionalarea;

c)1of7strands,or2of19strandsofgalvanizedsteelwirearebroken.

4.2.4.2Externalprocessingmethodofrepairingpre-twistedwireisasfollows:

a)Handleandsmoothandpolishthedamagedstrand;

b)Thelengthofpre-twistedwireshallnotbelessthan3pitchesandconformtotheprovisionsofDL/T763:

c)Thepre-twistedwireshallbeinclosecontactwiththewire,itscentershallbelocatedatthemostserious

damage,andthedamagedpartshallbecompletelycovered.

4.2.4.3Repairsleevetreatmentmethodisasfollows:

a)Restorethedamagedstrandtotheoriginaltwistedstate

b)Therepairsleeveshallcoverthedamagedpartcompletely,itscentershallbelocatedatthemostserious

damagedpart,andbothendsshallexceedtheedgeofthedamagedpartbymorethan20mm;

c)Therepairsleeveshallbeconstructedbyhydraulicpressure,anditsoperationshallcomplywiththe

provisionsofSDJ226.

4.2.5Treatmentofelongatedrepairsleeves

4.2.5.1Inthefollowingcircumstancesthatthecross-sectionalareaofgroundwireisreducedduetobroken

stranddamage,elongatedrepairsleevesshallbeprocessed.

a)Thedamagedcross-sectionalareaofaluminumstrandofaluminumcablesteelreinforcedis25%~60%ofthe

totalcross-sectionalareaofaluminumstrand;thedamagedcross-sectionalareaofthealuminumalloystrandsofthe

steelcorealuminumalloystrandis25%~60%ofthetotalcross-sectionalareaofthealuminumalloystrands;

b)Thedamagedcross-sectionalareaofaluminumstrandedwireandaluminumalloystrandedwireis17%~25%of

thetotalcross-sectionalarea.

c)2of7strandsor3of19strandsofgalvanizedsteelstrandarebroken.

4.2.5.2Thetreatmentmethodofelongatedrepairsleeveisasfollows:

a)Restorethestrandatthedamagedparttotheoriginaltwistedstate;

b)TherepairprocessshallcomplywithrelevantprovisionsofDL/T1069.

4.2.6Cutoffandreconnect

4.2.6.1Inthefollowingcasesthatthegroundwirestrandsarebroken,itmustbecutoffandre-connected.

a)Thedamagedcross-sectionalareaofaluminumstrandofaluminumcablesteelreinforcedisgreaterthan60%or

moreofthetotalcross-sectionalareaofaluminumstrand;Thedamagedcross-sectionalareaofthealuminumalloy

strandsofaluminumalloyconductorsteelreinforcedisgreaterthan60%ormoreofthetotalcross-sectionalareaof

thealuminumalloystrands;

8

b)1ormorestrandsofthesteelcoreofaluminumcablesteelreinforcedisbroken;1ormorestrandsofsteelcore

ofthealuminumalloyconductorsteelreinforcedisbroken;.

c)3of7strandsor4of19strandsofgalvanizedsteelwirearebroken.

d)Thefittingdamageandbrokenstrandscausepermanentdeformationofsteelcoreorinneraluminumstrands

thatcannotberepaired.

4.2.6.2Cut-offandreconnectingcanbehandledasfollows:

a)Beforeusingtheslicingsleeveforrepair,thehydraulicequipmentandmaterialsshallbecarefullychecked,and

theirspecificationsshallbeconsistentwiththegroundwiretoberepaired;

b)Forcut-offandreconnectingthegroundwire,thesteelcorecanbeconnectedbymeansofbuttjointorlapjoint.

Clean-up,drawing-inwire,hydraulicoperationandqualityinspectionoftheslicingsleeveandthegroundwireshall

becarriedoutinstrictaccordancewiththeprovisionsofSDJ226.

5Tower

5.1Generalrequirements

5.1.1Theperformanceofpartsandcomponentsofthetowerreplacedoraddedshallnotbelowerthanthe

designvalues.

5.1.2ThetighteningtorqueofboltsshallconformtotheprovisionsofDL/T5235.

5.1.3Theanti-unloadingandanti-looseningmeasurestakenforthemaintainedtowersshallnotbelowerthan

theoriginaldesignstandards.

5.2Towermaintenanceitem

5.2.1Theanti-corrosionconstructionoftowersshallbecarriedoutinstrictaccordancewiththetechnological

proceduresof“rustremovalprimerfinish”.

5.2.2Anti-dismantlingandanti-looseningtreatmentrequirementsfortowers:Forallboltsbelow8mofthe

towerandallboltsbelowthecrossarmofthetowerinareaswheretheftoccursfrequently,takeanti-theftmeasures;

forotherbolts,takeanti-looseningmeasures.Theinstallationofanti-unloadingandanti-looseningboltsshallmeet

therequirementsofDL/T5092.

5.2.3Addandreplacetowercomponents.

5.2.3.1Toaddtowercomponents,theholespacingandholelayoutofmissingcomponentsshallbemeasuredon

site.Forthespecificationsoftowercomponents,refertothedesigndrawings.Boltsofcorrespondingspecifications

andmodelsshallbeaddedaccordingtotherequirementsofthedrawingsafterprocessing.Thecomponentsto

replaceshallnotbeuseduntilgalvanized.

5.2.3.2Boltsofnewlyreplacedoraddedtowerpartsshallbetightenedtothespecifiedtorque.

5.2.3.3Thetowercomponentswithdeformationgreaterthanthespecifiedlimitcanbecorrectedbymeansofcold

correction.

6Foundation

6.1Generalrequirements

Afterthefoundationisrenovatedorrepaired,thestandardshallnotbelowerthantheoriginaldesignvalues.

6.2Foundationmaintenance

6.2.1Thefoundationwithcementfallingoff,crackandtheexposedsteelbarsshallberepaired,andthe

9

foundationseriouslyscouredbyfloodshallbereinforced.

6.2.2Beforereformingthefoundation,mixtestshallbeconductedaccordingtotheconcretestrengthspecified

inthedesign,andthetestresultsshallnotbeappliedforconstructionuntiltheymeetthespecifiedrequirements.For

reformingthefoundation,chlorinesaltisstrictlyprohibitedtomixintoconcrete,anddifferenttypesofcementare

strictlyprohibitedtomixinthesamefoundation.

7Insulator

7.1Generalrequirements

7.1.1Toreplaceasingleinsulatororawholestringofinsulators,dedicatedtoolsshallbeused.

7.1.2Theinsulationresistanceofanewinsulatorshallbegreaterthan500MΩ.

7.1.3Thesaltdensityofinsulatorsshallbemeasuredonaregularbasistoguidethelineantifouling.

7.1.4ThedeviationofinsulatoralignmentdirectionofstraightlinepoleshallbehandledaccordingtoDL/T

5235.

7.2Insulatormaintenanceitems

7.2.1Check

7.2.1.1Checkwhetherthelockingpinsfallofforcorroded,andwhethertheironcapandsteelfeetareinclined,

cracked,deformedorcorroded.

7.2.1.2Checkwhetherthereisanytraceofflashover,crack,burnordamageonporcelainorglassinsulators.

7.2.1.3Theinspectioncontentsofcompositeinsulatorsareasfollows:

a)Checkthecorrosiondegreeoftheendaccessoriesandtheslipandgapofthejoints;

b)Checkwhethertherearedegumming,cracksandslippagearisingineachjoint;

c)Checkwhetherthesurfaceofshediscracked,pulverized,crackedandthecrackdepthisgreaterthan0.1mm;

d)Checkwhetherthematerialsofshedandsheathbecomehardandbrittle,andabletowithstand90°upanddown

bendingfor3timesrespectivelywithoutbreaking;

e)Checkwhethertheshedandsheathmaterialshaveleakageandcorrosiontraces,whethertheaccumulatedlength

isgreaterthan10%ofthecreepagedistanceoftheinsulatorandwhetherthecorrosiondepthisgreaterthan30%of

thethicknessofthematerialattheinvolvedposition;

f)Checkwhetherthehydrophobicityoftheshedandsheathmaterialsdecreases,andtheserioushydrophobicity

decreaseismanifestedbycontinuouswaterfilmonthesurfaceoftheshedandsheath.

7.2.2Cleanupporcelainandglassinsulators

7.2.2.1Porcelainandglassinsulatorsaregenerallycleanedintwoways:power-offcleaningandlivecleaning.

7.2.2.2Thepower-offcleaningofporcelainandglassinsulatorsshallbecarriedoutpiecebypiece.Theinsulators

seriouslyfouledcanbewipedandcleanedbyspecialcleaningagent.

7.2.2.3Theinsulatorsontowerswhicharedifficulttocleancanbedismantledandcleanedupontheground.

7.2.3Sprayinganti-pollutionflashovercoating

7.2.3.1InsulatorsinheavilycontaminatedareascanbepaintedwithRTVanti-pollutionflashovercoatingsto

preventlinefailureincurredbypollutionflashover.

7.2.3.2ThepaintedRTVanti-pollutionflashovercoatingshallbeuniformlyattachedtothesurfaceofthe

insulator,andthecoatingthicknessshallmeettherequirementsofDL/T627.Thecoatingthicknessshallbe0.2mm

~0.3mmforClassIandIIpollutionareas,0.4mm~0.5mmforClassIIIandIVpollutionareasandseveresand

10

areas,whichcanbecompletedbytwoormultipletimesofpainting.

7.2.3.3InsulatorsmustbecleanedbeforeapplyingRTVanti-pollutionflashovercoating,andthecoatingshallbe

preventedfromsprayingontotheironcapduringspraying.

7.2.3.4RTVanti-pollutionflashovercoatingshallberecoatedafteritexpires.Beforerecoating,thesurfaceof

RTVanti-pollutionflashovercoatingmustbecleaned.

7.2.4Replacement

7.2.4.1Thereplacementofasingleinsulatororawholestringofinsulatorscanbeconductedindifferent

operationmodes.Theselectedtoolsandinstrumentsmustbesafeandreliable,andprotectivemeasuresshallbe

takentopreventthegroundwirefromfallingoff.

7.2.4.2Thenewinsulatorsshallbeintact,thesurfaceoftheshedshallbeclean,andtheinsulationresistance

valueshallbegreaterthan500MΩ.

7.2.4.3Theironcap,insulatorandsteelpinoftheinsulatorstringshallbeonthesameaxis,withthecompleteand

intactlockingpins,andtheopeningdirectionconsistentwiththeoriginalline.

7.2.4.4Forreplacingcompositeinsulators,softropesshallbeusedforlifting.Tramplingandsqueezingthe

surfaceofcompositeinsulators’shedsarestrictlyprohibited.Theinstallationofgradingringsforcomposite

insulatorsmustmeettherequirements.

8Fittings

8.1Generalrequirements

8.1.1Thereplacedfittingsshallmeettheoriginaldesignrequirements,beofthesamemodel,conformto

provisionsinDL/T683,andgetreliablyconnected.

8.1.2Whenreplacingtheconnectingfittingsofthegroundwire,takeprotectivemeasurestopreventtheground

wirefromfallingoff.

8.1.3Duringlinemaintenance,burrorprotrusiononthesurfaceofthefittingsshallbepreventedandthe

galvanizinglayershallnotbedamaged.

8.2Maintenanceitemsoffittings

8.2.1Check

8.2.1.1Checkwhetherthefittingsoftheoverheadgroundwirearecorroded,worn,cracked,loosened,

non-weldedordeformed,whetherthejointsrotateflexibly;whethertheboltsandpinsofeachpartareloose,falling

offandwornout.

8.2.1.2Checkwhetherthedischargeclearanceoftheinsulatedoverheadgroundwirechanges,andthe

installationdistancedeviationshallnotbegreaterthan±2mm.

8.2.1.3Alongtheinsulatorstring,checktheconnectionofwirefittingsandinsulatorsonebyonetoseeifthereis

anyimproperconnection,lackofpin,andwhetherthepartsaredamaged,corroded,worn,crackedordeformed,etc.

8.2.1.4Checkwhetherthevibrationdamperoftheconductorisloose.Ifso,checkwhetherthegroundwireis

worn.

8.2.1.5Thecontactsurfaceofthealuminumdrainageboardshallbeflatandsmooth,andconductivegreaseshall

becoatedbetweenthecontactsurfaces;Checkthedrainageplate(thread)forburnsandbrokenstrands;Check

whetherthetensionhydraulicclampboltsareloose,orspringgasketispressedflat.

8.2.1.6Itisnecessarytoopenandinspectthegroundwireclampinsectionscoveredwithice,gallopingand

11

pollutionflashoverorinsectionswithalongoperatinglife.Checkalongthelinewhetherthewireandspacerare

damaged,burned,orbrokenbyvibration,andwhethertheboltsofspacerarelooseorclawsaremissing.

8.2.2Replacement

8.2.2.1Afterreplacementofballheadhangingring,socketclevisandspringpin,checkandconfirmwhethertheir

interactionisreliableandintact.

8.2.2.2Themaintainedsuspensioninsulatorstringshallbeverticaltotheground.Underspecialcircumstances,

themaximumoffsetvaluealongthelineisnotgreaterthan300mm.Theoffsetvalueofthecontinuousup-hilland

down-hillsuspensionclampshallmeetthedesignrequirements.

8.2.2.3Thediameteroftheclosingpinshallmatchtheaperturewithmoderateelasticity.Thethreadingdirection

ofbolts,piercingpinsandspringpinsofallkindsoffittingsshallmeettherequirementsofGBJ50233.

8.2.2.4Forvarioustypesofaluminumstrandedwires,whicharetightenedwithwireclampfittingsmadeof

differentmaterials,thesurfaceofaluminumstrandsshallbewoundbyaluminumarmourtape.

9GroundingDevice

9.1Generalrequirements

9.1.1Beforethemodificationofgroundingdevice,themodificationplanshallbedeterminedbasedongeology,

topographyandoperatingexperience,etc.

9.1.2Thegroundingresistancemeasuredafternaturalsettlementofbackfillsoilshallprevailaftermodification

ofthegroundingdevice.

9.1.3Thetopoftheverticalgroundingconductorshallbeatleast0.6mawayfromtheground,andtheparallel

distancebetweentwohorizontalgroundingconductorsshallnotbelessthan5m.

9.1.4Thegroundingconductorsshallbeweldedforconnection,andtheweldingsizeshallmeetrelevant

requirements.Anti-corrosionmeasuresshallbetakenattheweldjoints.

9.2Maintenanc