《译文DLT 722014 变压器油中溶解气体分析和判断导则》

ICS29.040.10

E38

Filingnumber:47903-2015

ElectricPowerIndustryStandardofthePeople's

RepublicofChina

DL/T722—2014

ReplaceDL/T722—2000

GuidetotheAnalysisandtheDiagnosisofGasesDissolvedinTransformerOil

（ExposureDraft）

Issuedate:2014-10-15Implementationdate:2015-03-01

IssuedbyNationalEnergyAdministration

DL/T722—2014

Foreword

ThisstandardisdraftedinaccordancewiththerulesgivenintheGB/T1.1-2009Directivesfor

standardization—Part1:Structureanddraftingofstandards.

ThisstandardreplacesDL/T722-2000Guidetotheanalysisandthediagnosisofgasesdissolvedin

transformeroilinwhole.Exceptforeditorialrevisions,thefollowingtechnicaldeviationshavebeenmade

withrespecttoDL/T722-2000:

——The"dissolutionanddiffusionofgasesinoil"wasadded(seeArticle4.4ofthisstandard);

——Thespecificrequirementsforshorteningthecyclein"detectionunderspecialcircumstances"were

added(seeArticle5.4ofthisstandard);

——Thespecificcontentof“takeoilsamplefromoil-filledelectricalequipment”in“sampling”was

deleted,andonly“takegassamplefromgasrelayventnozzle”wasretained,andotheroriginal

specificcontentsaresubjecttorelevantregulationsinGB7597(seeChapter6ofthisstandard);

——Theoriginalcontentsin"removalofdissolvedgasfromoil"and"gasdetectionmethod"were

deleted,andtherelevantregulationsinGB/T17623shallprevail(seeChapter7andChapter8ofthis

standard);

——Thetitleof"Ex-worksandnewlycommissionedequipment"(see9.2ofthisstandard);

——Thegascontentrequirementsofvarioustypesofequipmentnewlycommissionedweremodified,it

wasclassifiedintovoltagelevels"330kVandabove"and"220kVandbelow",andthecontent

requirementsweremodifiedaccordingly(see9.2ofthisstandardand8.4.4of2000edition)；

——Thevoltageclassclassificationoftheinstrumenttransformerandthecorrespondingattentionvalues

weremodified,andtheattentionvaluesofthebushingweremodified(see9.3.1ofthisstandard);

——The"Principlesfortheapplicationofattentionvalues"wasadded,andsomecontentsweremodified

(see9.3.3ofthisstandard);

——Apartofthecontentof"Characteristicgasmethod"wasrevised(see10.1ofthisstandard);

——Thecodeof"low-temperatureoverheating(below150℃)"wasrevised(see10.2.1ofthisstandard);

——Thestructureandcorrespondingcontentof"faulttypejudgment"wererevised(seeChapter10of

thisstandard);

——AnnexA"SampleLabelFormat"andAnnexD"ApplicableConcentrationofStandardMixture"

weredeleted(seeAnnexof2000Edition);

——"Othertestitemsrecommendedwhenjudgingfaults"wasadded(seeAnnexDofthisstandard);

——Thedescriptionoftypicalfaultswasrevisedandfaultexampleswereadded(seeAnnexEofthis

standard);

——Aninformativeannex"GasDistributionCoefficient"wasadded(seeAnnexFofthisstandard).

ThisstandardwasproposedbytheChinaElectricityCouncil.

ThisstandardwaspreparedbytheTechnicalCommitteeforStandardizationofPowerTransformerinthe

PowerIndustry(DL/TC02).

Thisstandardwasdraftedby:ChinaElectricPowerResearchInstitute,StateGridOperationBranch,

StateGridHubeiElectricPowerCompanyElectricPowerResearchInstitute,StateGridLiaoningElectric

PowerCo.,Ltd.,StateGridJiangsuElectricPowerCompanyElectricPowerResearchInstitute,StateGrid

ElectricPowerResearchInstituteWuhanNARICo.,Ltd.,StateGridGansuElectricPowerCompanyElectric

PowerResearchInstitute,GuangdongPowerGridCompanyElectricPowerResearchInstitute,StateGridJilin

ProvinceElectricPowerCo.,Ltd.ElectricPowerResearchInstitute,StateGridEastChinaBranch,StateGrid

ShanghaiElectricPowerCompany,StateGridSuzhouPowerSupplyCompany,StateGridJiangsuElectric

PowerCompanyMaintenanceBranch,StateGridHenanElectricPowerCompanyElectricPowerResearch

Institute,StateGridShanghaiElectricPowerCompanyElectricPowerResearchInstitute,Shenyang

TransformerResearchInstituteCo.,Ltd.Company,TBEAShenyangTransformerGroupCo.,Ltd.,China

YangtzePowerCo.,Ltd.MaintenancePlant,NynasPetroleum(Shanghai)Co.,Ltd.

Maindraftersofthisstandard:WangJianyi,LingMin,LiJinzhong,SheZhenqiu,WangRuizhen,Wang

Shige,WuYihua,LiangZhiyu,FuQiang,LiShouxue,JiangYimin,ChenJiangbo,ZhangShuzhen,Cai

Shengwei,LiaoWenfeng,ZhouXiaofan,XuWanda,XuJiangang,HanJinhua,LiHonglei,PengWei,Chen

I

DL/T722—2014

Kui,LiuFeng,WangWeiguo,LiYongchun.

ThisstandardreplacesDL/T722-2000.

Thisisthesecondrevisededition.

Thepreviouseditionsofthisstandardareasfollows:

——SD187—1986；

——DL/T722—2000。

Pleasesendanyopinionsorsuggestionsputforwardduringtheexecutionofthisstandardtothe

StandardizationManagementCenterofChinaElectricityCouncil(No.1,Lane2,BaiguangRoad,Beijing,

100761)

TranslationunitofEnglishversionofthisstandard:

Maintranslatorsandeditorsofthisstandard:

II

DL/T722—2014

GuidetotheAnalysisandtheDiagnosisofGasesDissolvedinTransformerOil

1Scope

Thisstandardspecifiesthemethodforfaultidentificationandfaulttypejudgmentofoil-filledelectrical

equipmentbasedonthedissolvedandfreegasesintransformeroil(mineralinsulatingoil),andrecommends

furthermeasures.

Thisstandardisapplicabletoelectricalequipmentthatusestransformeroilandpaper(board)asthemain

insulatingmaterials,includingtransformers,reactors,instrumenttransformers,andbushings.

2NormativeReferences

Thefollowingreferenceddocumentsareindispensablefortheapplicationofthisstandard.Fordated

references,onlytheeditioncitedapplies.Forundatedreferences,thelatesteditionofthereferenceddocument

(includinganyamendments)applies.

GB/T7597Methodofsamplingfortransformerandturbineoilsinelectricpowerindustry

GB/T17623Determinationofcomponentcontentsofgasesdissolvedininsulatingoilbygas

chromatographymethod

DL/T984Guideforthediagnosisofinsulationaginginoil-immersedpowertransformer

IEC60599Mineraloil-impregnatedelectricalequipmentinservice-Guidetotheinterpretationof

dissolvedandfreegasesanalysis

3TermsandDefinitions

Forthepurposesofthisdocument,thefollowingtermsanddefinitionsapply.

3.1

characteristicgas

Gasesthatarevaluableforjudgingtheinternalfaultsofoil-filledelectricalequipment,i.e.hydrogen(H2),

methane(CH4),ethane(C2H6),ethylene(C2H4),acetylene(C2H2),carbonmonoxide(CO),carbondioxide

(CO2)

3.2totalhydrocarbon

Totalamountoffourhydrocarboncharacteristicgases,i.e.CH4,C2H6,C2H4andC2H2.

3.3freegas

Gasinsolubleinoil(suchasthegasintheupperpartoftheoilsurfaceoftheequipmentandthegasinthe

gasrelay).

4SourcesofGasesDissolvedinOil

4.1Decompositionoftransformeroil

Transformeroilisamixtureofmanyhydrocarbonmoleculeswithdifferentmolecularweights.Electricor

thermalfaultcanbreaksomeC—HbondsandC—Cbonds,whichisaccompaniedbythegenerationofasmall

numberofactivehydrogenatomsandfreeradicalsofunstablehydrocarbons.Thesehydrogenatomsorfree

radicalsquicklyrecombinethroughcomplexchemicalreactionstoformH2andlow-molecularhydrocarbon

gases,suchasCH4,C2H6,C2H4,C2H2,etc.,andmayalsogeneratecarbonsolidparticlesandhydrocarbon

polymers(X-wax).TheoxidationofoilwillalsogenerateasmallamountofCOandCO2,whichcan

accumulatetoasignificantamountoveralongperiodoftime.

AnnexAofthisstandardshowstherelationshipbetweenthegasformedinthethermalequilibriumstate

andthetemperaturecalculatedbyHalsterdinthethermodynamicequilibriumtheory.

4.2Decompositionofsolidinsulatingmaterials

Solidinsulationmaterialsrefertopaper,laminatedcardboardandwoodblocks,etc.,whicharecellulose

insulationmaterials.Celluloseisalong-chainhighlypolymerizedhydrocarbon(C6H10O5)ncomposedofmany

glucosemonomers.ThethermalstabilityoftheC—Obondandglucosidebondisweakerthanthatofthe

C—Hbondinoil.Thepolymerwillbecrackedabove105°C,andcompletelycrackedandcarbonizedabove

300°C.Alongwithwater,alargeamountofCOandCO2,asmallamountoflow-molecularhydrocarbongases,

furfuralanditsseriesofcompoundswillbegeneratedduringinthepolymercracking.

4.3Othersourcesofgas

ThewatercontainedintheoilcanreactwithirontogenerateH2;whenthetemperatureishighandthereis

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DL/T722—2014

O2dissolvedintheoil,somepaint(alkydresin)intheequipmentmaygeneratealargeamountofH2underthe

catalysisofsomestainlesssteel,orthecatalyticreactionofstainlesssteelwithoilcanalsogeneratealarge

numberofH2;newstainlesssteelmayalsoadsorbH2duringprocessingorgenerateH2duringwelding;some

modifiedpolyimideinsulatingmaterialscanalsogeneratecertaincharacteristicgaseswhencontactedwithoil;

oilcanalsogeneratecertaincharacteristicgasesundersunlight.

Thesourceofgasalsoincludessomegasintheinjectedoilitself;aftertroubleshooting,thegasadsorbedin

thedevicebodyisnotcompletelyremoved,butslowlyreleasedintotheoil;Theoilintheoilchamberofthe

switchoftheon-loadvoltageregulatingtransformerleakstothemaintankofthetransformer,andelectric

sparksareformedwhentheselectiveswitchoperatesatacertainposition(suchaspolarityconversion),which

willgenerateC2H2intheoilofthetransformerbody;Thegasgeneratedbythefaultoftheauxiliaryequipment

ofthecoolingsystem(suchassubmersibleoilpump)willalsoentertheoiloftransformerbody;Repairing

weldingofoiltankwillleadtooildecompositionandgenerategases.

4.4Dissolutionanddiffusionofgasesdissolvedinoil

Thegasgeneratedbythedecompositionofoilandpaperinsulationmaterialsiscontinuouslydissolvedin

theoilthroughconvectionanddiffusionintheoil.Whenthegasgenerationrateisgreaterthanthedissolution

rate,apartofitwillgatherintofreegasandenterthegasrelayoroilconservator.Therefore,whenthereisgas

accumulatedinthegasrelayoroilconservator,detectingthegasesinitwillhelptomakeajudgmentonthe

internalconditionoftheequipment.

5DetectionCycle

5.1Detectionbeforecommissioning

Neworoverhauled66kVandaboveequipmentshallbedetectedatleastoncebeforebeingputinto

operation.Detectionisnotrequiredforfullysealedinstrumenttransformersandbushingsthatarenotsampled

asrequiredbythemanufacturer.Iftheinducedvoltagewithstandandpartialdischargetestsarecarriedouton

site,andetectionshallbeconductedbeforeandafterthetest,andtheoilsampleshallbetakenatleast24hours

afterthetestiscompleted.

5.2Detectionduringnewcommissioning

Neworoverhauledtransformersandreactorsof66kVandaboveshallbedetectedatleastonceevery1day,

4days,10days,and30daysafterbeingputintooperation.

Neworoverhauledinstrumenttransformersof66kVandaboveshouldbedetectedoncewithin3months

afterbeingputintooperation.Detectionisnotrequiredforfullysealedinstrumenttransformersthatarenot

sampledasrequiredbythemanufacturer.

5.3Periodicdetectionduringoperation

Theperiodicdetectioncycleoftheequipmentinoperationshallbecarriedoutinaccordancewiththe

provisionsofTable1.

Table1Periodicdetectioncycleofequipmentinoperation

EquipmenttypeEquipmentvoltagelevelorcapacityDetectioncycle

Voltage330kVandabove

Powerplantstep-uptransformerswithacapacityof3months

240MVAandabove

TransformersandreactorsVoltage220kV,capacity120MVAandabove6months

Voltage66kVandabove,capacity8MVAandabove1year

InstrumenttransformerVoltage66kVandabove1~3years

Bushing—Whennecessary

Note:Thedetectioncyclesofothergradesoftransformers,reactorsandinstrumenttransformersis

self-regulated.Thefullysealedinstrumenttransformersandbushingswhicharenotsampledasspecifiedby

themanufactureraregenerallynotdetectedduringthewarrantyperiod.Afterthewarrantyperiodhas

expired,itmaybedeterminedbytheactualsituation,butitisnotappropriatetotakesamplesundernegative

pressure.

5.4Detectionunderspecialcircumstances

Underspecialcircumstances,detectionshallbecarriedoutaccordingtothefollowingrequirements:

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DL/T722—2014

a)Whentheequipmenthasexceptionalconditions(suchastransformergasrelayaction,differential

protectionaction,pressurereleasevalveaction,andhighcurrentimpact,over-excitationoroverload,

instrumenttransformerexpanderaction,etc.),oilsamplesshallbetakenfordetection.Intheeventof

gasaccumulatedinthegasrelay,agassampleneedstobetakenfordetection.

b)Whenthefollowingexceptionalitiesaresuspectedintheequipment,thedetectioncycleshallbe

shortenedaccordingtothesituation,soastomonitororexitoperation.Duringthemonitoring

process,ifthegrowthtrendisobvious,othercorrespondingmeasuresmustbetaken;ifthecontentis

stableafterthreetimesoftestsundersimilaroperatingconditions,thetestcyclecanbeappropriately

extendeduntilthenormaltestcycleisrestored.

1)Overheatfaults.Whenitissuspectedthatthemainmagneticcircuitorthemagneticleakage

circuitisfaulty,thecyclecanbeshortenedtoonceaweek;whenitissuspectedthatthe

conductivecircuitisfaulty,itshouldbeshortenedtoatleastonceaday.

2)Dischargefaults.Whenlow-energydischargeissuspected,itshouldbeshortenedtoonceaday;

whenhigh-energydischargeissuspected,carryoutfurtherdetectionorexitoperation.

6Sampling

6.1Takeoilsamplesfromoil-filledelectricalequipment

AccordingtotherelevantregulationsofGB/T7597fortheanalysisandsamplingofgasesdissolvedin

transformeroil.

6.2Takegassamplefromtheventnozzleofthegasrelay

6.2.1Overview

Whengasaccumulatesinthegasrelay,agassampleshallbetakenfordetection.Thecompositionand

contentofthesegasesareoneoftheimportantcriteriaforjudgingtheequipmentfaultandthenatureofthe

fault.Inordertoreducetheimpactofdifferentre-dissolutionratesofdifferentcomponents,thegassample

mustbetakenoutinthetimeasshortaspossibleanddetectedassoonaspossible.

6.2.2Containerfortakinggassample

Awell-sealedglasssyringeorgassamplingbagshallbeused.Theglasssyringe,ifused,shallbe

lubricatedbytheequipmentbodyoilbeforesamplinginordertoensurethesyringeissealedwell.

6.2.3Methodoftakinggassample

Whentakinggassamples,putasmallpieceoflatextubeontheventnozzleofthegasrelay,andconnecta

smallmetalthree-wayvalvetothesyringeattheotherendofthelatextube(payattentiontotheinnerdiameter

ofthelatextube,thejointbetweenthedeflatingvalveofthelatextubeandthegasrelayandthemetal

three-wayvalveshallbesealed).Fortheoperationstepsandconnectionmethods,seetherelevantregulations

ontheanalysisandsamplingofgasesdissolvedintransformeroilinGB/T7597.

Thefollowingstepscanbeused:

a)Turnthethree-wayvalve,flushtheconnectingpipelineandthesyringewiththegasinthegasrelay

(thisstepisnotnecessarywhenthegasvolumeislow);turnthethree-wayvalvetoemptythesyringe;

turnthethree-wayvalveagaintotakeagassample;Inthecaseofdown-drawingofgasrelaypipe,

themethodisthesame,butoilshallberemovedfromthesyringe.

b)Aftersampling,closetheventnozzle,turnthethree-wayvalvetosealthesyringeport,removethe

syringetogetherwiththethree-wayvalveandthelatextube,thenremovethethree-wayvalve,and

immediatelysealthesyringewithasmallrubberhead(exhausttheairinthesmallrubbertipasmuch

aspossible).

7RemovetheGasDissolvedinOil

SubjecttotherelevantregulationsinGB/T17623.

8GasComponentContentDetectionMethod

SubjecttotherelevantregulationsinGB/T17623.

9FaultIdentification

9.1Overview

Theoil-paperinsulationmaterialinsidetheoil-filledelectricalequipmentwillgraduallyageand

decomposeundertheactionofheatandelectricityduringnormaloperation,andgenerateasmallamountofH2,

lowmolecularhydrocarbongases,CO,andCO2etc.;Incaseofthermalandelectricalfault,thesegaseswill

alsobegenerated.Thetwosourcesofgascannotbedistinguishedtechnically,andtherearenostrictlimitsin

value.Inaddition,itisrelatedtomanyvariablefactorssuchasload,temperature,O2contentandwatercontent

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DL/T722—2014

inoil,oilprotectionsystemandcirculationsystem,etc.Therefore,whenjudgingtheequipmentfaultandthe

severityofthefault,acomprehensivejudgmentshallbemadebasedontheabsolutevalueofthegascontent,

thegrowthrate,theoperatingstatus/structuralcharacteristicsoftheequipment,andtheexternalenvironment.

Sometimesthereisnofaultintheequipment,buttheabove-mentionedgasesmayalsoappearintheoildueto

otherreasons.Therefore,payattentiontothesourcesofthesegasesthatmaycausemisjudgment.Fordetails,

see4.3ofthisstandard.

Inordertoidentifyfaults,attentionvaluesforgascontentandgasgenerationrateareproposed.Attention

valuereferstothevalueofthecontentorincrementofthecharacteristicgastowhichattentionshallbepaid,

anditisactuallynotastandardforclassifyingequipmentstatus.Whentheattentionvalueisexceeded,the

detectioncycleshallbeshortenedaccordingtotheprovisionsof5.4ofthisstandard,andacomprehensive

analysisshallbecarriedouttogetherwithotherjudgmentmethods.

9.2Requirementsforcontentofgasdissolvedinoilbeforenewequipmentisputintooperation

Beforethenewequipmentisputintooperation,thecontentofgasesdissolvedintheoilshallmeetthe

requirementsofTable2,andthereshallbenoobviousdifferencebetweenthetwodetectionresultsbeforeand

aftertheoperation.

Table2Requirementsforcontentofgasesdissolvedinoilbeforenewequipmentisputintooperation

μL/L

Content

EquipmentGascomposition

330kVandabove220kVandbelow

Hydrogen<10<30

TransformersandreactorsAcetylene<0.1<0.1

Totalhydrocarbons<10<20

Hydrogen<50<100

InstrumenttransformerAcetylene<0.1<0.1

Totalhydrocarbons<10<10

Hydrogen<50<150

BushingAcetylene<0.1<0.1

Totalhydrocarbons<10<10

9.3Attentionvaluesofgasesdissolvedinequipmentoilduringoperation

9.3.1Attentionvaluesofgasesdissolvedinoil

WhenthecontentofgasesdissolvedintheequipmentoilexceedsthevaluelistedinTable3during

operation,attentionshallbepaidtoit.

Table3Attentionvaluesofcontentofgasesdissolvedinequipmentoilinoperation

μL/L

Content

EquipmentGascomposition

330kVandabove220kVandbelow

Hydrogen150150

Acetylene15

Totalhydrocarbons150150

Transformersandreactors

(See10.2.3.1ofthis(See10.2.3.1ofthis

CO

standard)standard)

(See10.2.3.1ofthis(See10.2.3.1ofthis

Carbondioxide

standard)standard)

Hydrogen150300

CurrentinstrumentAcetylene12

transformer

Totalhydrocarbon100100

VoltageinstrumentHydrogen150150

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DL/T722—2014

transformerAcetylene23

Totalhydrocarbons100100

Hydrogen500500

BushingAcetylene—12

Totalhydrocarbon150150

Note:Thevalueslistedinthistablearenotapplicabletothegassamplestakenfromthegasrelay(seeChapter11

ofthisstandard).

9.3.2Attentionvalueofgasgrowthrate

Thegasgrowthrate(gasgenerationrate)isdirectlyrelatedtothefaultenergy,thetemperatureofthefault

point,andthescopeofthefault.Therateofgasgenerationisalsorelatedtothetypeofequipment,load

conditionsandthevolumeoftheinsulatingmaterialusedanditsagingdegree.Whenjudgingtheserious

conditionofequipmentfault,theescapelossofgasshallalsobetakenintoconsideration.Itshallbenotedthat

thegasgenerationtimemayonlybeacertainperiodoftimewithinthetwodetectioncycles,sothecalculated

valueofthegasgenerationratemaybelessthantheactualvalue.

Thegasgenerationrateiscalculatedinthefollowingtwoways:

a)Absolutegasgenerationrate,thatis,theaveragevalueofacertaingasgeneratedperoperatingday,is

calculatedasfollows:

(1)

��,2−��,1�

Where:

��=∆�×�

——Absolutegenerationrate,mL/day;

Ci,2——Concentrationofacertaingasintheoilmeasuredduringthesecondsampling,μL/L;

��

Ci,1——Concentrationofacertaingasintheoilmeasuredduringthefirstsampling,μL/L;

——Actualrunningtimeinthetwosamplingintervals,indays;

M——Totaloilvolumeofequipment,t;

ρ∆—�—Densityofoil,t/m3.

b)Relativegasgenerationrate,thatis,thepercentageofacertaingascontentincreaserelativetothe

originalvaluepermonthofoperation(orconvertedtoamonth),iscalculatedasfollows:

(2)

��,2−��,11

��=��,1×∆�×100%

Where:

γr——Relativegasgenerationrate,%/month;

Ci,2——Concentrationofacertaingasintheoilmeasuredduringthesecondsampling,μL/L;

Ci,1——Concentrationofacertaingasintheoilmeasuredduringthefirstsampling,μL/L;

——Actualrunningtimeinthetwosamplingintervals,indays;

Fortransformersandreactors,theattentionvaluesofabsolutegasgenerationratesareshowninTable4;

thea∆t�tentionvalueofrelativegasgenerationrateoftotalhydrocarbonis10%(forequipmentwithverylow

initialcontentoftotalhydrocarbon,thiscriterionshouldnotbeused).

Forequipmentwithaslowincreaseingascontent,thegasgrowthoftheequipmentcanbemonitoredby

thegasonlinemonitoringdeviceatanytime.

Table4Attentionvaluesofabsolutegasgenerationratesofgasesdissolvedinequipmentoilin

operation

mL/d

GascompositionSealedtypeOpentype

Hydrogen105

Acetylene0.20.1

Totalhydrocarbon126

Carbonmonoxide10050

Carbondioxide200100

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DL/T722—2014

Note1:Whenacetylene<0.1μL/Landtotalhydrocarbonislessthanthenewequipmentcommissioning

requirements,theabsolutegasgenerationrateoftotalhydrocarbonmaynotbeanalyzed(judged).

Note2:Attheinitialstageofoperationofthenewequipment,thegasgenerationrateofCOandCO2mayexceed

theattentionvaluesinthetable.

Note3:Whenthedetectioncyclehasbeenshortened,theattentionvaluesinthistableareforreferenceonly,and

theyarenotapplicablewhenthecycleisshort.

9.3.3Applicationprincipleofattentionvalues

Theapplicationprinciplesofattentionvaluesofgascontentandgasgenerationrateareasfollows:

a)Theattentionvalueofgascontentisnotthesolebasisforjudgingfaultinsidetheequipment.When

thegascontentexceedstheattentionvalue,thedetectionperiodshallbeshortenedaccordingto5.4b)

ofthi