ASTMD149美标标准固体绝缘材料电压击穿的实验方法Word文档格式.docx

ASTMD149美标标准固体绝缘材料电压击穿的实验方法Word文档格式.docx

《ASTMD149美标标准固体绝缘材料电压击穿的实验方法Word文档格式.docx》由会员分享，可在线阅读，更多相关《ASTMD149美标标准固体绝缘材料电压击穿的实验方法Word文档格式.docx（9页珍藏版）》请在冰豆网上搜索。

1.3ThistestmethodisintendedtobeusedinconjunctionwithanyASTMstandardorotherdocumentthatreferstothistestmethod.Referencestothisdocumentneedtospecifytheparticularoptionstobeused（see5.5）.

1.4Itissuitableforuseatvarioustemperatures,andinanysuitablegaseousorliquidsurroundingmedium.

1.5Thistestmethodisnotintendedformeasuringthedielectricstrengthofmaterialsthatarefluidundertheconditionsoftest.

1.6Thistestmethodisnotintendedforuseindeterminingintrinsicdielectricstrength,direct-voltagedielectricstrength,orthermalfailureunderelectricalstress（seeTestMethodD3151）.

1.7Thistestmethodismostcommonlyusedtodeterminethedielectricbreakdownvoltagethroughthethicknessofatestspecimen（puncture）.Itisalsosuitableforusetodeterminedielectricbreakdownvoltagealongtheinterfacebetweenasolidspecimenandagaseousorliquidsurroundingmedium（flashover）.WiththeadditionofinstructionsmodifyingSection12,thistestmethodisalsosuitableforuseforprooftesting.

1.8ThistestmethodissimilartoIECPublication243-1.AllproceduresinthismethodareincludedinIEC243-1.DifferencesbetweenthismethodandIEC243-1arelargelyeditorial.

1.9Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.SpecifichazardstatementsaregiveninSection7.Alsosee6.4.1.

ASTMD149美标标准固体绝缘材料电压击穿的实验方法（三）

3.1Definitions:

3.1.1dielectricbreakdownvoltage（electricbreakdownvoltage）,n—thepotentialdifferenceatwhichdielectricfailureoccursunderprescribedconditionsinanelectricalinsulatingmateriallocatedbetweentwoelectrodes.（SeealsoAppendixX1.）

3.1.1.1Discussion—Thetermdielectricbreakdownvoltageissometimesshortenedto“breakdownvoltage.”

3.1.2dielectricfailure（undertest）,n—aneventthatisevidencedbyanincreaseinconductanceinthedielectricundertestlimitingtheelectricfieldthatcanbesustained.

3.1.3dielectricstrength,n—thevoltagegradientatwhichdielectricfailureoftheinsulatingmaterialoccursunderspecificconditionsoftest. 

3.1.4electricstrength,n—seedielectricstrength.

3.1.4.1Discussion—Internationally,“electricstrength”isusedalmostuniversally.

3.1.5flashover,n—adisruptiveelectricaldischargeatthesurfaceofelectricalinsulationorinthesurroundingmedium,whichmayormaynotcausepermanentdamagetotheinsulation.

3.1.6Fordefinitionsofothertermsrelatingtosolidinsulatingmaterials,refertoTerminologyD1711.

ASTMD149美标标准固体绝缘材料电压击穿的实验方法（四） 

4.SummaryofTestMethod

4.2Mostcommonly,thetestvoltageisappliedusingsimpletestelectrodesonoppositefacesofspecimens.Theoptionsforthespecimensarethattheybemoldedorcast,orcutfromflatsheetorplate.Otherelectrodeandspecimenconfigurationsarealsosuitableforusetoaccommodatethegeometryofthesamplematerial,ortosimulateaspecificapplicationforwhichthematerialisbeingevaluated.

4.1Alternatingvoltageatacommercialpowerfrequency（60Hz,unlessotherwisespecified）isappliedtoatestspecimen.Thevoltageisincreasedfromzeroorfromalevelwellbelowthebreakdownvoltage,inoneofthreeprescribedmethodsofvoltageapplication,untildielectricfailureofthetestspecimenoccurs.

5.SignificanceandUse

5.1Thedielectricstrengthofanelectricalinsulatingmaterialisapropertyofinterestforanyapplicationwhereanelectricalfieldwillbepresent.Inmanycasesthedielectricstrengthofamaterialwillbethedeterminingfactorinthedesignoftheapparatusinwhichitistobeused.

5.2Testsmadeasspecifiedhereinaresuitableforusetoprovidepartoftheinformationneededfordeterminingsuitabilityofamaterialforagivenapplication;

andalso,fordetectingchangesordeviationsfromnormalcharacteristicsresultingfromprocessingvariables,agingconditions,orothermanufacturingorenvironmentalsituations.Thistestmethodisusefulforprocesscontrol,acceptanceorresearchtesting.

5.3Resultsobtainedbythistestmethodcanseldombeuseddirectlytodeterminethedielectricbehaviorofamaterialinanactualapplication.Inmostcasesitisnecessarythattheseresultsbeevaluatedbycomparisonwithresultsobtainedfromotherfunctionaltestsorfromtestsonothermaterials,orboth,inordertoestimatetheirsignificanceforaparticularmaterial.

5.4ThreemethodsforvoltageapplicationarespecifiedinSection12:

MethodA,Short-TimeTest;

MethodB,Step-by-StepTest;

andMethodC,SlowRate-of-RiseTest.MethodAisthemostcommonly-usedtestforquality-controltests.However,thelonger-timetests,MethodsBandC,whichusuallywillgivelowertestresults,willpotentiallygivemoremeaningfulresultswhendifferentmaterialsarebeingcomparedwitheachother.Ifatestsetwithmotor-drivenvoltagecontrolisavailable,theslowrate-of-risetestissimplerandpreferabletothestep-by-steptest.TheresultsobtainedfromMethodsBandCarecomparabletoeachother.

5.5Documentsspecifyingtheuseofthistestmethodshallalsospecify:

5.5.1Methodofvoltageapplication,

5.5.2Voltagerate-of-rise,ifslowrate-of-risemethodisspecified,

5.5.3Specimenselection,preparation,andconditioning,

5.5.4Surroundingmediumandtemperatureduringtest,

5.5.5Electrodes,

5.5.6Whereverpossible,thefailurecriterionofthecurrentsensingelement,and

5.5.7Anydesireddeviationsfromtherecommendedproceduresasgiven.

5.6Ifanyoftherequirementslistedin5.5aremissingfromthespecifyingdocument,thentherecommendationsfortheseveralvariablesshallbefollowed.

5.7Unlesstheitemslistedin5.5arespecified,testsmadewithsuchinadequatereferencetothistestmethodarenotinconformancewiththistestmethod.Iftheitemslistedin5.5arenotcloselycontrolledduringthetest,itispossiblethattheprecisionsstatedin15.2and15.3willnotbeobtained.

5.8Variationsinthefailurecriteria（currentsettingandresponsetime）ofthecurrentsensingelementsignificantlyaffectthetestresults.

5.9AppendixX1.containsamorecompletediscussionofthesignificanceofdielectricstrengthtests.

ASTMD149美标标准固体绝缘材料电压击穿的实验方法（六）

6.Apparatus6.1VoltageSource—Obtainthetestvoltagefromastep-uptransformersuppliedfromavariablesinusoidallow-voltagesource.Thetransformer,itsvoltagesource,andtheassociatedcontrolsshallhavethefollowingcapabilities.6.1.1Theratioofcresttoroot-mean-square（rms）testvoltageshallbeequalto=265%（1.34to1.48）,withthetestspecimeninthecircuit,atallvoltagesgreaterthan50%ofthebreakdownvoltage. 

6.1.3Thecontrolsonthevariablelow-voltagesourceshallbecapableofvaryingthesupplyvoltageandtheresultanttestvoltagesmoothly,uniformly,andwithoutovershootsortransients,inaccordancewith12.2.Donotallowthepeakvoltagetoexceed1.48timestheindicatedrmstestvoltageunderanycircumstance.Motor-drivencontrolsarepreferableformakingshort-time（see12.2.1）orslow-rate-of-rise（see12.2.3）tests.

6.1.4Equipthevoltagesourcewithacircuit-breakingdevicethatwilloperatewithinthreecycles.Thedeviceshalldisconnectthevoltage-sourceequipmentfromthepowerserviceandprotectitfromoverloadasaresultofspecimenbreakdowncausinganoverloadofthetestingapparatus.Ifprolongedcurrentfollowsbreakdownitwillresultinunnecessaryburningofthetestspecimens,pittingoftheelectrodes,andcontaminationofanyliquidsurroundingmedium.

6.1.5Itisimportantforthecircuit-breakingdevicetohaveanadjustablecurrent-sensingelementinthestep-uptransformersecondary,toallowforadjustmentconsistentwiththespecimencharacteristicsandarrangedtosensespecimencurrent.Setthesensingelementtorespondtoacurrentthatisindicativeofspecimenbreakdownasdefinedin12.3.

6.1.6Thecurrentsettingislikelytohaveasignificanteffectonthetestresults.Makethesettinghighenoughthattransients,suchaspartialdischarges,willnottripthebreakerbutnotsohighthatexcessiveburningofthespecimen,withresultantelectrodedamage,willoccuronbreakdown.Theoptimumcurrentsettingisnotthesameforallspecimensanddependingupontheintendeduseofthematerialandthepurposeofthetest,itisoftendesirabletomaketestsonagivensampleatmorethanonecurrentsetting.Theelectrodeareaislikelytohaveasignificanteffectuponthechoiceofcurrentsetting.

6.1.7Itispossiblethatthespecimencurrent-sensingelementwillbeintheprimaryofthestep-uptransformer.Calibratethecurrent-sensingdialintermsofspecimencurrent.

6.1.8Exercisecareinsettingtheresponseofthecurrentcontrol.Ifthecontrolissettoohigh,thecircuitwillnotrespondwhenbreakdownoccurs;

ifsettoolow,itispossiblethatitwillrespondtoleakagecurrents,capacitivecurrents,