Productintroduction
In1911,HeikeKamelinHonnesofLeidenUniversityintheNetherlandsdiscoveredthattheresistancedroppedtozerowhenthetemperatureofmercurydroppedto4.2K.Andmanymetalsandalloyshavethecharacteristicsoflosingresistanceatlowtemperaturessimilartomercury.Thisspecialconductivityiscalled"superconductingstate"byOnes.Peoplecallaconductorinasuperconductingstate"superconductor".TheDCresistivityofasuperconductorsuddenlydisappearsatacertainlowtemperature,whichiscalledthe"zeroresistanceeffect".Aspiralcoilismadeofsuperconductorwire.Whenthecoilisenergized,amagneticfieldisgenerated,andthestoredenergyisproportionaltotheproductofthesquareofthecurrentandtheinductance.Ifthecoilconductorhasresistance,theenergywillbeconsumedintheformofJouleheat,whiletheresistanceofthesuperconductoriszerointhecryogenicstate,andthereisnoJouleheatloss.Shortthetwoendsofthesolenoid,andthemagneticenergycanbepermanentlystored.Whennecessary,thetwoendsofthecoilareconnectedwithanexternalload,andthemagneticenergystoredinthecoilcanbeconvertedintoelectricenergy,whichcanbetakenoutatanytime.
Systemequipment
SuperconductingMagneticEnergyStorage(SMES)usessuperconductingcoilstodirectlystoreelectromagneticenergy,andthenreturnstheelectromagneticenergytothegridorAnelectricalfacilityforotherloads.Itusesthelowlossandfastresponseofsuperconductingmagnetstostoreenergy.Itisakindofinterfacebetweenmodernpowerelectronicconvertersandpowersystems,whichcanstoreelectricalenergy(rectificationmethod)andreleaseelectricalenergy(invertermethod).)Fastresponsedevice.Ittakesadvantageofthezeroresistancecharacteristicofsuperconductors.Itcannotonlystoreelectricalenergywithoutlossinthesuperconductorinductancecoil,butalsoachievelarge-capacitystorageofelectricalenergy,improvepowersupplyquality,increasesystemcapacity,andmanyotherpurposes.Itcanalsobeusedbypowerelectronicconverters.Quicklyexchangeactiveandreactivepowerwithexternalsystemstoimprovethestabilityoftheentirepowersystemandimprovethequalityofpowersupply.Itisgenerallycomposedofsuperconductingcoils,cryogeniccontainers,refrigerationdevices,flowconverters,andmeasurementandcontrolsystemcomponents.Asshowninthefigure"SuperconductingEnergyStorageSystemControlandPowerLineLayout":
Theapplicationofsuperconductingenergystorageinthepowersystemwasfirstproposedasadevicetobalancethepowerload.In1969,FerrierfirstconceivedofusingalargesuperconductingmagneticenergystoragedevicetobalancethedailyloadchangesintheFrenchpowersystemandadjustthepeaksandvalleysofthepowersystem.Becauseofitsveryrapidpowerexchangewiththegrid,coupledwiththedevelopmentofpowerelectronicstechnology,superconductingenergystoragecanexchangefour-quadrantactivepowerandreactivepowerindependentlywiththesystematthesametime.Peoplehaveproposedtousesuperconductingenergystorage.Itcanbeusedtosuppressthelow-frequencyoscillationphenomenonthatoccursonthelong-distanceACpowertransmissionsystem.Itcanbeusedtoreduceoreveneliminatethelow-frequencypoweroscillationofthegridtoimprovethevoltageandfrequencycharacteristicsofthegrid.Itcanalsobeusedtoadjustthereactivepowerandpowerfactorstoimprovethestabilityofthepowersystem.sex.
Inrecentyears,peoplehaveturnedtheirattentiontotheuseofsmallsuperconductingenergystoragetoimprovepowerquality.Forexample,todealwithshort-termvoltagedropsandsuddenpoweroutages.Becausesolvingsuchproblemsrequiresanenergystoragesystemwithhugepowerratherthanhugeenergy,itiseasiertoimplement.Thecurrentdesignshowsthatthestoragecapacityofasuperconductingenergystoragepowerstationcanbeintherangeof0.1MWhto10GWh(1MWh=3.6×10J),anditsstoragecapacityisquitelarge.Storagesystemsofdifferentcapacitiesaresuitablefordifferentpurposesandapplications.
Productadvantages
Becausetheresistanceofthesuperconductoriszero,theenergystoragelossisextremelysmall,andtheefficiencyofsuperconductingenergystoragecanreachmorethan90%,whichisbetterthanpumpingenergystorageandflywheelenergystorage.Andtheefficiencyofbatterystorageismuchhigher.Theadvantagesofsuperconductingenergystoragearemainlyhighpower,lightweight,smallsize,lowloss,fastresponseandsoon.Thesuperconductingenergystoragesystemhasaseriesofadvantagesthatotherenergystoragetechnologiescannotmatch:
(1) Може да съхранява енергия за дълго време без загуби и ефективността му на преобразуване надвишава 90%.
(2)Itcanbeconnectedtothepowergridbyadoptingtheconvertertechnologyofpowerelectronicdevices,andtheresponsespeedisfast(millisecondlevel).
(3)Sincethecapacityofitsenergystorageandpowermodulationsystemcanbeindependentlyselectedinalargerange,thesuperconductingenergystoragesystemcanbebuiltintotherequiredhigh-powerandhigh-energysystem.
(4)Няма въртяща се част с изключение на вакуумната и хладилната система и експлоатационният живот е дълъг.
(5) Конструкцията не е ограничена от местоположението, поддръжката е проста и замърсяването е малко.
Developmentstatus
Atpresent,alotofmanpowerandmaterialresourceshavebeeninvestedintheresearchanddevelopmentofsuperconductingenergystoragesystems,mainlytodevelopthepracticalapplicationofminiaturesuperconductingenergystoragedevices.TheUnitedStates,Germany,andJapanhaveputforwardproposalsforthedevelopmentof100kWhclassmicrosuperconductingenergystoragedevices,suchassuperconductingenergystoragesystemsusedinmaglevtrains,computerbuildings,andhigh-risebuildings;microsuperconductingenergystoragesystemsoftheUnitedStatesIGCandAMSCConductiveenergystoragedevices(1-10MJ)havebeencommercialized,andAMSCiscurrentlydevelopinganewpowerdistributionSMES(D-SMES)forpowerregulation.
(1) Статут на изследване на свръхпроводящо хранилище за генериране на енергия в Съединените щати.
TheresearchonsuperconductingenergystoragesystemsintheUnitedStatesisrelativelyearly.In1971,anelectricalenergystoragesystemcomposedofsuperconductinginductioncoilsandthree-phaseAC/DCGraetz(Graetz)bridgewasinventedattheUniversityofWisconsin.Afteradetailedanalysisoftheeffect,theyfoundthatthefastresponsecharacteristicsofthedeviceareveryeffectiveinsuppressingtheoscillationofthepowersystem.
In1974,thefirstSMESconnectedtothegridwastestedatLosAlamosLaboratory(LASLD).From1976to1982,LASLandBPA(BonnevillePowerAdministration)cooperatedtobuilda30MJ/10MWsuperconductingenergystoragesystem.Thissystemsuccessfullysuppressedthe500kVdouble-circuitACfromthePacificNorthwesttoSouthernCaliforniaat1,500km.Thelowfrequency0.35Hzspontaneouspoweroscillationofthetransmissionline.
TheUnitedStatesbegantostudyasuperconductingstoragepowerstationwithacapacityof30MJ(8.3kWh)in1978,andwasconnectedtothepowersystemonthewestcoastoftheUnitedStatesfortrialoperationin1983-1984.Thepurposeistoverifythesystemstability.In1987,theUnitedStatesdesignedasuperconductingenergystoragepowerstationwithacapacityof21MWh,whichisusedasanon-groundlaserpowersource,whichcanrelease400MWofelectricitywithin100s(low-speedoperationmode).Constructionofthepowerstationbeganin1991,andvarioustestswerecarriedoutin1993.Thesuperconductingcoilhasadiameterofabout130mandaheightofabout5m.Itadoptsaspiralshapeandthecoilcurrentis200kA.
Inthe1970s,theUnitedStatesandothersweremainlydevotedtotheresearchoflarge-scalesuperconductingenergystoragetechnology,whichwasusedforpowersystemloadregulationandothermilitaryapplications.Inthelate1970s,theUnitedStatesdevelopeda30MJsuperconductingenergystoragedeviceandinstalleditona500kVtransmissionlineonthewestcoasttoeliminateits0.35Hznegativedampingoscillationandincreaseitstransmissionpower.Satisfactoryresultswereobtainedinthetest,buttheenergystoragedevicefailedtocontinueoperationduetothefailureofthecryogenicsystemtomeettheoperatingrequirementsandfailures.Inthe1980s,theU.S.militaryproposedaplantodevelopa20.4MWhsuperconductingenergystorageengineeringexperimentalmodelandcarriedoutpre-researchwork.AftertheendoftheColdWar,theplanwasalsosuspended.Inthe1990s,inordertoimprovethereliabilityoftheAlaskapowergrid,theUnitedStatesproposedaplantodevelopa1.8GJsuperconductingenergystoragedevice.Theprojectcompletedthedesignandbeganpre-research.Later,duetofundingandotherreasons,thedevelopmentplanwassuspended.
(2)Състояние на изследването на свръхпроводящо хранилище за енергия в Япония.
ThedevelopmentofsuperconductingenergystoragetechnologyinJapanhasbeenmainlycarriedoutbyuniversitiesandnationalresearchinstitutionssincethelate1970s.In1986,JapanestablishedtheSuperconductingEnergyStorageResearchAssociation.ItsmissionistorealizethepracticalapplicationofsuperconductingenergystorageandpromotetheindependentdevelopmentofJapanesesuperconductingenergystoragetechnology.Theassociationhas50memberunits,includingfamousuniversities,researchinstitutions,companiesandfactoriesinJapan.Sincethemid-1980s,alotofanalysis,design,andexperimentalresearchworkhasbeencarriedout.Later,variousresearchinstitutionsinJapanalsobegantoconductresearch.Japan'sSuperconductingEnergyStorageResearchAssociation,theInternationalSuperconductingIndustrialTechnologyResearchCenter,andtheCentralElectricPowerAssociationhaveallcarriedoutpracticalresearchonsuperconductingenergystoragetechnology.In1985,KyushuUniversitydesigneda100kJSMEStostudytheapplicationandsystemstabilityintheDCgrid.In1991,KyushuElectricPowerCompanyconnecteda30kJsuperconductingenergystoragesystemtoa60kWhydroelectricgeneratortoconductatesttoimprovethestabilityofthegenerator,andachievedgoodexperimentalresults;andKyushuElectricPowerCompanyhascooperatedwithKyushuUniversitytocarryout36MJSMEStestandisdesigningandconstructinga360MJ/20MWSMESafterconnectingtothegridfordemonstrationoperation,andthendevelopinga1260MJ/500MWmultifunctionalSMES.KyushuElectricPowerCompanyconductedaseriesoffieldexperimentsonsuperconductingenergystorageforsystemstabilityatitsaffiliatedAriuragawaHydropowerStation,whichshowedthatthestand-alonesystemcanbestablycontrolledbyasuperconductingenergystoragedevicewithageneratorcapacityof10%to50%.
(3) Статут на изследване на свръхпроводящо хранилище на енергия в Русия.
RussianresearchonSMESbeganintheSovietUnion.ThesuperconductingTokamakT15superconductingmagnetbuiltin1988canstoreupto370-760MJ.Sincethe1990s,theRussianNationalLaboratoryhasbuilta12MJSMES,carriedoutasuperconductingenergystoragedesignof100MJ/inductance8H/current5kA/strongestmagneticfield5.4T,andbuilta900MJsuperconductingenergystoragesystem.Guideenergystoragesystem.
(4) Статут на изследване на свръхпроводящо съхранение на енергия в Китай.
mycountryhasbeenworkingonlow-temperaturesuperconductivitysincethe1960s.Bythemid-1980s,alotofworkhasbeencarriedoutinhigh-energyaccelerators,superconductingmagneticfluidpropulsion,magneticfluidpowergeneration,magneticseparation,nuclearfusion,magneticresonanceimaging,magneticlevitationtrains,andsuperconductingstrongmagneticfields.Acertainfoundationhasbeenlaidforsuperconductingmagnetsandcryogenictechnology.
In1997,theInstituteofElectricalEngineeringoftheChineseAcademyofSciencessuccessfullydevelopeda25kJ(300A/220V)superconductingenergystorageprototype.In2005,theKeyLaboratoryofAppliedSuperconductivitycompletedtheThe100kJ/25kWsuperconductingcurrentlimiting-energystoragesystemwasdeveloped,andshort-circuitandvoltagecompensationexperimentswerecarriedout.Thisisanewtypeofsuperconductingforcedevicewithindependentinnovation,whichrealizestheintegrationofmultiplefunctions.Subsequently,the1MJ/0.5MVAhigh-temperaturesuperconductingenergystoragesystemwasdeveloped,whichincludedhigh-temperaturesuperconductingmagnetsystems,refrigerationsystems,powerelectronicsystems,andonlinemonitoringsystems.Theenergystoragecoiliscomposedof44Bi-2223double-cakecoils,withaninductanceof6.4H,anoperatingcurrentof560A,andoperatingat4.2K.TheenergystoragesystemwasinstalledinMentougousubstationin2007,andwastestedandoperatedtoimprovepowerquality,becomingmycountry'sfirstsuperconductingsubstation.
OnApril19,2011,theworld’sfirstdistribution-levelsuperconductingsubstationdevelopedbytheInstituteofElectricalEngineeringoftheChineseAcademyofScienceswasputintoactualpowerdistributionnetworkforprojectdemonstrationoperationintheNationalHigh-techIndustrialDevelopmentZoneofBaiyinCity,GansuProvince,Thisisalsotheonlysuperconductingsubstationputintodemonstrationoperationintheworld.Theoperatingvoltagelevelofthesubstationis10.5kV,integrated1MJ/0.5MVAhightemperaturesuperconductingenergystoragesystem,1.5kAthree-phasehightemperaturesuperconductingcurrentlimiter,630kVAhightemperaturesuperconductingtransformerand75mlong1.5kAthree-phaseAChightemperaturesuperconductingAvarietyofnewsuperconductingpowerdevicessuchasconductivecables.Itbecamethefirsthigh-temperaturesuperconductingenergystoragesystemintheworldthatwasconnectedtothegridatthattime.Itscorecomponent,high-temperaturesuperconductingmagnet,wasalsothelargestintheworldatthattime.The10.5kV/1.5kAthree-phasehigh-temperaturesuperconductingcurrentlimiterwasthefirstinmycountry,Theworld'sfourthgrid-connectedhigh-temperaturesuperconductingcurrentlimiter.The630kVA/10.5kV/0.4kVhigh-temperaturesuperconductingtransformerwasthefirsthigh-temperaturesuperconductingtransformerinmycountryandthesecondgrid-connectedoperationintheworld.Itwasalsotheworld'slargestamorphousalloytransformeratthattime,withlightweight,smallsizeandefficiency.Ithastheadvantagesofhigh,nofirehazard,noenvironmentalpollution,etc.,anditalsohasacertaincurrentlimitingeffect.The75mlong10.5kV/1.5kAthree-phaseAChigh-temperaturesuperconductingcablewasthelongestthree-phaseAChigh-temperaturesuperconductingcableintheworldatthattime.Itadoptedasegmenteddesign,plug-inintegrateddesignandimplementationplan.Thisisthefirstsuperconductingsubstationinmycountryandeventheworld.Itmarksthatmycountryhastakentheleadinrealizingtheoperationofacompletesuperconductingsubstationsystemintheworld,anditisthefirsttimethatmanysuperconductingpowerdeviceshavebeenintegratedtobuildacompletesuperconductingsubstation.
In2012,thehigh-temperaturesuperconductingenergystoragesystemindependentlydevelopedbytheChinaElectricPowerResearchInstitutefortwoyearssuccessfullyachievedgrid-connectedpowercompensationintheStateGridCorporation’sPowerSystemDynamicModelLaboratory.Thesuccessoftheexperimentshowsthatmycountryhasindependentlymasteredthekeytechnologiesofthesecond-generationhigh-temperaturesuperconductingenergystoragesystemunitstructure,integration,control,protection,andpracticalapplicationofpowertransmissionanddistributionengineering,anditsresearchresultscanbeusedforthenextstageofsuperconductivityapplicationAsolidfoundationislaidfortechnologicalscientificresearch,experimentaldemonstrationoperation,systemanalysisandevaluation.
Prospectsforsuperconductingenergystorage
Becauseofitsfastresponsecharacteristics,SMEScannotonlybeusedtoadjustthepeakvalue,butalsocanstoreemergencybackuppowertoincreasetheallowabletransmissioncapacity(forexample,formycountryInthecaseofveryunevenresourcedistribution,theuseofsuperconductingenergystoragesystemscanbetterimplementwest-to-eastpowertransmission),improvethestabilityofthesystem,andimprovethequalityofpowersupply.Inthissense,superconductingenergystoragecanberegardedasaflexiblealternatingcurrenttransmissionsystem(FACTS)devicethatcanexchangeactivepowerwiththegrid,soithasmorepowerfulfunctionsandcantransformthepowersystemfrompassivestabilizationtoactivestabilization..
Ofcourse,therearestillsomedifficultiesinthepracticaltechnologyofsuperconductingenergystorage.Themainshortcomingsofsuperconductingenergystorageareobvious,andtheseshortcomingslimititsindustrializationandapplication.Theapplicationandindustrializationofsuperconductivitytechnologyfacethreeproblems:①Thecriticaltemperatureofsuperconductingmaterialsneedstobeimproved;②Thepriceofsuperconductingmaterialsisstillrelativelyhigh,andsomearedozensorevenhundredsoftimeshigherthanconventionalmaterials;③Thepreparationofthecryogenicrefrigerationsystemappliedbysuperconductingtechnologyisstillrelativelycomplicated,andthemaintenance-freelifeoftherefrigeratorisrelativelyshort.Atthesametime,thelow-temperatureandhigh-voltageinsulationtechnologyofsuperconductingequipment,real-timedetectiontechnology,integrationtechnology,andmatchingandcoordinatedoperationwithconventionalsystemsalsoneedfurtherresearch.
InordertoacceleratethepracticalprocessofSMES,themainresearchdirectionsinthefutureare:①Reducecosts.Atpresent,thecostofSMES,especiallysmallSMES,ishigherthanothercorrespondingtechnologies.Itisveryimportanttodeveloplow-costSMES;②Develophigh-temperaturesuperconductingwires(HTS)toincreasethecriticalcurrentdensityofwires;③Researchonconverters.Furtherstudytheparalleltechnologyofcurrentequalization,reducehigh-orderharmonicstoreduceconverterlossesandsafetyissues;④Researchcontrolstrategies.Accordingtomultipleindicatorssuchassystemcapacity,SMESparameters,controlpurpose,etc.,especiallyfromtheperspectiveofthepowersystem,selectanddesignanexcellentcontrolstrategy;⑤Reducelossandimprovestability.ToimprovetheefficiencyofSMESenergystorage,itisnecessarytoreducetheACloss;inordertoreducetheACloss,itisnecessarytoincreasethepoweroftherefrigerator.Atthesametime,inordertoimprovethestabilityofthesuperconductingcoil,itisalsonecessarytoreducetheACloss;⑥researchquenchprotectiontechnology.DevelopedreliableandflexibleDCcircuitbreakersandpermanentcurrentswitchestoimprovethesafetyofSMES.