Designation:D3300−12StandardTestMethodforDielectricBreakdownVoltageofInsulatingOilsofPetroleumOriginUnderImpulseConditions1ThisstandardisissuedunderthefixeddesignationD3300;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthedeterminationofthedielec-tricbreakdownvoltageofinsulatingoilsinahighlydivergentfieldunderimpulseconditions.1.2Thevaluesstatedininch-poundunitsaretoberegardedasstandard.ThevaluesgiveninparenthesesaremathematicalconversionstoSIunitsthatareprovidedforinformationonlyandarenotconsideredstandard.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2D923PracticesforSamplingElectricalInsulatingLiquidsD2864TerminologyRelatingtoElectricalInsulatingLiq-uidsandGases2.2IEEEDocuments:IEEEStandard4-1995TechniquesforHigh-VoltageTest-ing33.SignificanceandUse3.1Thistestmethodismostcommonlyperformedusinganegativepolaritypointopposingagroundedsphere(NPS).TheNPSbreakdownvoltageoffreshunusedoilsmeasuredinthehighlydivergentfieldinthisconfigurationdependsonoilcomposition,decreasingwithincreasingconcentrationofaromatic,particularlypolyaromatic,hydrocarbonmolecules.3.2Thistestmethodmaybeusedtoevaluatethecontinuityofcompositionofanoilfromshipmenttoshipment.TheNPSimpulsebreakdownvoltageofanoilcanalsobesubstantiallyloweredbycontactwithmaterialsofconstruction,byserviceaging,andbyotherimpurities.Testresultslowerthanthoseexpectedforagivenfreshoilmayalsoindicateuseorcontaminationofthatoil.3.3Althoughpolarityofthevoltagewavehaslittleornoeffectonthebreakdownstrengthofanoilinuniformfields,polaritydoeshaveamarkedeffectont...
