简介：Thispaperintroducestheconfigurationandtheoperationprinciplesofahighpowerdirectcurrentcircuitbreaker(DCCB).Thecommutatingcurrentprincipleofthebreakerisde-scribedindetailswithitstheoryandsimulationanalysis.ThetestresultspresentedshowthattheDCCBmeetstherequirementsforquenchingprotection.ItwillbeusedasthemainbreakerforquenchprotectioninEAST.

简介：Hugoniotrelationsofatwo-dimensionalaxialshockwithcurrentandmagneticfieldinacylindricalshocktubewereinvestigatedbyanumericalmethod.Theradialprofilesofthemagneticfield,electriccurrent,pressures,flowvelocitiesandtemperaturesbetweentheupanddown-streamradialforce-balancedplasmaoftheshockwererevealedbynumericalanalysis.Itisclearlyfoundthattheaxialshockcanleadtotwoeffects:oneisaninverseskineffect(i.e.,thecurrentdensityrisestowardsthecenteroftheconductor),theanotherisareversedcurrenteffectwhichoccursneartheedgeandaboutahalfradius.Itisalsofoundthattheradialgradientofpressure,densityandtemperatureallbecomeverylargenearthecenterduetotheaxialshock.

简介：Radiationsimulationutilizingplasmaradiationsources(PRS)generatesalargenumberofundesirabledebris,whichmaydamagetheexpensivediagnosingdetectors.Anultrafastshutter(UFS)drivenbypulsedhighcurrentcanerectaphysicalbarriertotheslowlymovingdebrisafterallowingthepassageofX-rayphotons.TheUFSconsistsofapairofthinmetalfoilstwistingtheparallelaxesinaNyloncassette,compressedwithanoutermagneticfield,generatedfromafastcapacitorbank,dischargingintoasingleturnloop.Atypicalcapacitorbankisof7.5μFchargingvoltagesvaryingfrom30kVto45kV,withcorrespondingcurrentsofapproximately90kAto140kAanddischargingcurrentperiodsofapproximately13.1μs.Ashutterclosingtimeasfastas38microsecondshasbeenobtainedwithanaluminiumfoilthicknessof100micrometersandacross-sectionalareaof15mmby20mm.Thedesign,constructionandtheexpressionsofthevalve-closingtimeoftheUFSarepresentedalongwiththemeasuredresultsofvalve-closingvelocities.

简介：Neutralbeaminjectionisoneofthemainplasmaheatingmethodsinnuclearfusiondevices.InordertosupportthescientificstudyoftheExperimentalAdvancedSuperconductingTokamak(EAST),amegawatt-levelhighcurrentionsourceisdesignedandmanufacturedintheASIPP,andtheprogressandpreliminarytestresultswillbepresentedinthispaper.

简介：AbridgearmprototypeofITERpoloidalfield(PF)convertermoduleshasbeendesignedandfabricated.Non-cophasecounterparallelconnectionischosenasthearmstructureoftheprototype.Amongallfactorsaffectingcurrentsharing,armstructureisthemainone.Duringthedesignofthearmprototype,anovelmethodbasedoninductancematrixesisemployedtoimprovethecurrentsharingofthebridgearm.Thetestresultsontheprototypeshowthatthecurrentsharingperformanceofthearmprototypeismuchbetterthanrelevantdesignrequirement,andthatthematrixmethodisveryeffectivetoanalyzeandsolvethecurrentsharingproblemsofthyristorconverters.

简介：ARogowskicoilisdevelopedtodetectthenanosecondpulsesignalsofthedischargecurrentwithawidebandwidthof800kHzto106MHzandhighsensitivityof2.22V/A.Perfor-mancetestsshowthattheRogowskicoilhasbothexcellentdynamicandstaticcharacteristics.CalibratingresultsandthecomparisonbetweenthestandardcurrentshuntandthedevelopedRo-gowskicoilforthemeasurementofnanoseconddischargepulsesdemonstratethatthedevelopedRogowskicoilcanreproducetheactualwaveformofthedischargecurrentaccurately.

简介：Ahigh-currentvacuumarc(HCVA)withtheconsiderationofanodevaporismod-eledandsimulated.First,fromtheHCVAcolumnmodel,theheatfluxdensitytotheanodeisobtained,whichisputintotheanodeactivitymodel,andtheparameterdistributions(suchasthevaportemperatureandvelocity)ofanodevaporareobtainedfromthesimulationresultsoftheanodeactivitymodel.Then,byiteratingandcalculatingtheHCVAcolumnmodelandanodeactivitymodel,theinteractionbetweentheHCVAcolumnandtheanodevaporissimulatedandanalyzed.Inthesimulation,thedistributionoftheaxialmagneticfield(AMF)generatedbytheelectrodesystemiscalculatedbysoftwareANSYS.Thesimulationresultsshowthattheinfluenceofanodevaporontheparameterdistributionsinthearccolumnissignificant.Thesimulationresultsarealsocomparedwiththevacuumarcphotograph.

简介：

简介：

简介：Becausethelargermetallicsurroundsareheatedbytheeddycurrent,whichisgeneratedbytheACcurrentflowingthroughtheACbusbarintheInternationalThermonuclearExperimentalReactor(ITER)poloidalfield(PF)convertersystem,shieldingoftheACbusbarisrequiredtodecreasethetemperatureriseofthesurroundstosatisfythedesignrequirement.ThreespecialtypesofACbusbarwithnaturalcooling,aircoolingandwatercoolingbusbarstructurehavebeenproposedandinvestigatedinthispaper.Foreachcoolingscheme,a3Dfinitemodelbasedontheproposedstructurehasbeendevelopedtoperformtheelectromagneticandthermalanalysistopredicttheiroperationbehavior.Comparingtheanalysisresultsofthethreedifferentcoolingpatterns,watercoolinghasmoreadvantagesthantheotherpatternsanditisselectedtobethethermaldissipationpatternfortheACbusbarofITERPFconverterunit.TheapproachtoqualifythesuitablecoolingschemeinthispapercanbeprovidedasareferenceonthethermaldissipationdesignofACbusbarintheconvertersystem.

简介：Hybridcircuitbreaker(HCB)technologybasedonavacuuminterrupterandaSF6interrupterinserieshasbecomeanewresearchdirectionbecauseofthelow-carbonrequirementsforhighvoltageswitches.Thevacuuminterrupterhasanexcellentabilitytodealwiththesteeprisingpartofthetransientrecoveryvoltage(TRV),whiletheSF6interruptercanwithstandthepeakpartofthevoltageeasily.AnHCBcantakeadvantageoftheinterruptersinthecurrentinterruptionprocess.Inthisstudy,anHCBmodelbasedonthevacuumiondiffusionequations,iondensityequation,andmodifiedCassie-Mayrarcequationisexplored.Asimulationplatformisconstructedbyusingasetofsoftwarecalledthealternativetransientprogram(ATP).AnHCBprototypeisalsodesigned,andtheshortcircuitcurrentisinterruptedbytheHCBunderdifferentactionsequencesofcontacts.ThevoltagedistributionoftheHCBisanalyzedthroughsimulationsandtests.TheresultsdemonstratethatifthevacuuminterrupterwithstandstheinitialTRVandinterruptsthepost-arccurrentfirst,thentherecoveryspeedofthedielectricstrengthoftheSF6interrupterwillbefast.Thevoltagedistributionbetweentwointerruptersisdeterminedbytheirpost-arcresistance,whichhappensaftercurrent-zero,andsubsequently,itisdeterminedbythecapacitiveimpedanceafterthepost-arccurrentdecaystozero.

简介：

简介：TheHTScurrentleadsofsuperconductingmagnetsforlargescalefusiondevicesandhighenergyparticlecolliderscanreducethepowerconsumptionforcoolingby2/3comparedwithconventionalleads.Theresistivesectionsofhigh-ratedcurrentleadsareusuallymadeofaheatexchangercooledbygasflow.Thesupplyofthecoolingmassflowincursmorethan90%ofthecoolingcostfortheHTSleads.Themassflowraterequirementdependsnotonlyonthelengthandmaterialoftheresistiveheatexchanger,butalsoontheheattransfercoefficientandHEXsurface,thejointresistanceatthecoldendanditscoolingapproach.Thedesignandoperationofasheet-stackHEXwithalargerspecificsurfaceandamuchsmallerhydraulicdiameterarepresentedinthepaper.ThetestresultsofanHTSleadoptimizedfor8kAshowthata98.4%efficiencycanbeachieved.

简介：Inresponsetothecurrentimbalancephenomenonanditsharmfulness,acurrentsharingcircuitmodelisbuiltup,whichrevealstheunderlyingcausesforthecurrentimbalancethroughaquantitativeanalysis.Then,afeasibleapproachofimprovement,namelyenlargementofthelengthofconnectionbusbars,isproposed.Aftertheamendment,itcanbeseenthatthecurrentsharingcoefficientisalmostunityunderratedorfaultcurrentconditions.

简介：ThesolutionofGrad-Shafranovequationdeterminesthestationarybehavioroffusionplasmainsideatokamak.Tosolvetheequationitisnecessarytoknowthetoroidalcurrentdensityprofile.Recentworksshowthatitispossibletodetermineamagnetohydrodynamic(MHD)equilibriumwithreversedcurrentdensity(RCD)profilesthatpresentsmagneticislands.InthisworkweshowanalyticalMHDequilibriumwithaRCDprofileandanalyzethestructureofthevacuumvectorpotentialassociatedwiththeseequilibriausingthevirtualcasingprinciple.

简介：Theeffectofarcplasmaonelectrodeerosioninaliquidmetalcurrentlimiter(LMCL)isstudied.Basedonasimplifiedtwo-dimensionalmagnetohydrodynamicmodel,theelongatedGaInSnmetalvaporarcanditscontractionprocessinaliquidmetalcurrentlimiteraresimulated.Thedistributionsoftemperature,pressureandvelocityofthearcplasmaarecalculated.Thesimulationresultsindicatethattheelectrodeerosionismainlycausedbytwohightemperaturegasjetflowsarisingfromthepressuregradient,whichisaresultofthenon-uniformarctemperaturedistribution.Thegasflows,whichactasjetsontotheelectrodesurface,leadtotheevaporationoftheelectrodematerialformthesurface.Aredesignstructureoftheelectrodeisproposedandimplementedaccordingtotheanalysis,whichgreatlyincreasedtheservicelifeoftheelectrode.

简介：Adirect-currentairplasmajetoperatedunderwaterpresentsthreestablemodesincludinganintermittently-pulseddischarge,aperiodically-pulseddischargeandacontinuousdischargewithincreasingthepowervoltage.Thethreedischargemodeshavedifferentappearancesfortheplasmaplumes.Moreover,gapvoltage-currentcharacteristicsindicatethatthecontinuousdischargeisinanormalglowregime.Spectrallinesfromreactivespecies(OH,N_2,N_2~+,H_α,andO)havebeenrevealedintheemissionspectrumoftheplasmajetoperatedunderwater.SpectralintensitiesemittedfromOHradicalandoxygenatomincreasewithincreasingthepowervoltageorthegasflowrate,indicatingthatreactivespeciesareabundant.Thesereactivespeciescausethedegradationofthemethylenebluedyeinsolution.Effectsoftheexperimentalparameterssuchasthepowervoltage,thegasflowrateandthetreatmenttimeareinvestigatedonthedegradationefficiency.Resultsindicatethatthedegradationefficiencyincreaseswithincreasingthepowervoltage,thegasflowrateorthetreatmenttime.Comparedwithdegradationintheintermittently-pulsedmodeortheperiodically-pulsedone,itismoreefficientinthecontinuousmode,reaching98%after21mintreatment.

简介：

简介：Implementationofaweb-basedlogbooksystemonEASTisintroduced,whichcanstorethecommentsfortheexperimentsintoadatabaseandaccessthedocumentsviavariouswebbrowsers.Thethree-tiersoftwarearchitectureandasynchronousaccesstechnologyareadoptedtoimprovethesystemeffectively.Authorizeduserscanviewtheinformationofreal-timedischarge,commentsfromothersandsignalplots;add,delete,orrevisetheirowncomments;searchsignaldataorcommentsundercomplicatedsearchconditions;andcollectrelevantinformationandoutputittoanexcelfile.Thewebpagescanbeautomaticallyupdatedafteranewdischargeiscompletedandwithoutrefreshment.

简介：Thecurrentsheathvelocityin0.25TorrgaspressureofFilippovtypeplasmafocusisstudiedexperimentally.Byusingtwotridimensionalmagneticprobesontopoftheanodesurface,thecurrentsheathvelocityismeasuredforargon,oxygenandnitrogen.Additionally,theeffectofchargingvoltageonthecurrentsheathvelocityisstudiedinbothaxialandradialphases.Wefoundthat,themaximumcurrentsheathvelocitiesatbothradialandaxialphasesarerespectively4.33±0.28(cm/μs)and3.92±0.75(cm/μs)withargonastheworkinggasat17kV.Also,theminimumvaluesofcurrentsheathvelocityare1.48±0.15(cm/μs)attheradialphaseand1.14±0.09(cm/μs)attheaxialphasewithoxygenat12kV.Thecurrentsheathvelocityattheradialphaseishigherthanthatattheaxialphaseforallgasesandvoltages.Inthisstudy,variationofthefullwidthhalfmaximum(FWHM)ofmagneticprobesignalswithvoltageisinvestigatedfordifferentgasesatradialandaxialphases.