国家电网专业技术人员电力英语水平考试补全短文.docx
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国家电网专业技术人员电力英语水平考试补全短文
补全短文
Passage1Functionsofpowertransmission
Thefunctionof
(1)istosendpowerfrompowerplantstoloadcenterortoexchangepowerbetweenpowernetworksinordertoattainthegeneration-consumptionbalanceorthesupply-demandbalancebetween
(2).Powertransmissioniscompletedbystep-upsubstations,(3).Thetransmissionlinemainlyconsistsofthetransmissionconductors(cables),polesortowers,insulators,overheadgroundwires,andgroundingdevices.The(4)canreducethelinelossandthevoltagedrop,ensurethepowerquality,raisetheeconomyof(5).Theincreaseoftransmissionlinevoltagecannotonlyraisetheamountoftransmittedpower,butalsoreducethelinelossandlinevoltagedrop,andimprovethevoltagequality.
A.step-downsubstationsandconnectedtransmissionequipment
B.powernetworkoperation
C.powertransmission
D.transmissionathighvoltage
E.powernetworks
Passage2Substationmisoperationanditspreventing
Themisopemtionthatcanleadto
(1)mainlyare:
①on-loadswitchingofisolatingswitch;②connecting
(2);③closingthecircuitbreaker(isolatingswitch)withgroundlines(groundswitch)earthed.
The“fivepreventings”for(3)includes:
①preventingthewrongopeningorclosingofcircuitbreaker;②preventingtheonloadopeningandclosingofisolatingswitch;③preventing(4);④preventingtheclosingofcircuitbreakerwithgroundingwire
connected;⑤preventing(5).
A.preventingthemisoperationinsubstation
B.theclosingofgroundingswitchwithpoweron
C.accidentsintheelectricaloperationofthesubstation
D.thepersonsfromillegalenteringthelivedbay
E.thegroundingwire(closingthegroundingswitch)withpoweron
Passage3Abriefintroductiononthedevelopmentofsupercriticalboilersandtheirmainadvantages
In
(1)suchasU.S.A,JapanandEuropeancountries,thesupercriticalboilerhasbeendevelopedsincethe60soflastcentury.Ithasbeenprovedbydataandexperience,thesupercriticalunithas
(2).Asforitsreliability,becausethesteam-waterflowpassagesinsupercriticalboilerissameasthatinthe(3),thereisn’tanythingspecial.Butasfarashydrauliccharacteristic,asymbolofreliability,isconcerned,inasupercriticalboiler,undersupercriticalcondition,mediumisofsinglephasewhichhasa(4).Sothattheproblemcausedbyunevendistributionofsteamphaseandwaterphasecanbeavoided.Itisadmittedthat,if(5),bothsupercriticalandsubcriticalunitscangetanexcellentreliabilityindex.
A.goodhomogenizationofdistribution
B.someadvancedcountries
C.wholeprocessmanagementisstrengthened
D.greatadvantagesoileconomyandenvironmentalprotection
E.subcriticalonce-throughboiler
Passage4Steamgenerationanduse
Steamisoneofman’sdependableservantsMoreandmoreinthebackground,steamisdoingmoreandmoreworkforman.In
(1)steammaybeseenonlyattheteakettle,buttheelectricityusedmaybegeneratedbyburningcoalorgasandproducingsteamtoturnthegeneratorrotorsinthepowerplantEvenif
(2)bynuclearfission,thegenerationofelectricityisstillaccomplishedby(3).
IntheU.S.A.thedemandforelectricitydoubleseverytenyears.Forthemostpartwaterresourcessuitableforpowergenerationarealreadyinservice,exceptforemergencystandbyandpeak-loadunits;approximately90%of(4)utilizessteam.The(5)isexpandinginmostcountriesoftheworldexceptforthecountrieswhereavailablewaterpowerresourcesaregreaterthanpowerneeds.
A.firstgeneratingsteam
B.anelectricallyheatedhome
C.useofsteamforelectricpowergeneration
D.thenewgeneratingcapacitybeinginstalled
E.thefuelisuraniumandtheheatissupplied
Passage5Circuitbreaker
Circuitbreakersareautomaticallyoperatedhighvoltage(orhighcurrent)switches.Circuitbreakersarerequired
(1)byswitchingcircuitson,bycarryingloadandbyswitchingcircuitsoffundermanualorautomaticsupervision.Theirdutyisasfollows:
Inclosedpositionthecircuitbreakermustbeagoodconductorforthenormalloadcurrent.Inopenpositionthegapacrossthecontactsshallhavefoilinsulationlevel.Atopeningoperatingthecircuitbreakermustbeable
(2)tomanythousandsofamperes,andindependentlyofthecharacteristicsfrompurelyinductivetofullycapacitive.Atclosingoperationthecircuitbreakermustclosefastandbesafealsoagainstfullshortcircuitconditions.Theymust,therefore,beeffectiveinstantaneouslywhenarecalledupon(3)withoutmovement.Asthecircuitbreakeristhelastlinkinthechainofprotectiveequipment,thecircuitbreakerreliabilityis(4)ofthetotalelectricpowersystemsotheimportance(5)cannotbeoveremphasized.
A·toperformanyswitchingoperationafterlongperiods
B.tocontrolelectricalpowernetworks
C.ofthecircuitbreaker
D.toswitchthecurrentwhichcanbefromafewamperes
E.ofthehighestimportanceforhighreliability
Passage6Theratioofdistancetoheightofpumped-storagepowerplant
Forpumped-storagepowerplant,generallytheratioofdistancetoheight(l),Distance-heightratio
(2)tothedropbetweenupperandlowreservoirthatisL/H.Theheadofsimplepumped-storagepowerplantconsistsoftwoparts,theyarenaturaltopographicelevationdifferenceandelevationdifferenceformedbydam.Ofcourse,theheadderivedfromtopographicelevationdifference(3),soinselectingplantsite,theconditionthatnotonlyaheightdifferenceisavailablebutalsonoveryhighdamofupperreservoirisnecessaryshouldbeconsidered.SmallerL/Hvalueindicatesashorterwatertransportationline,thentheengineeringconstructioncostcanbesaved.Butinmanycircumstances,topographiccondition(4),sowecan’tsaythesmallestL/Hvalue(5).Innewlyconstructedthreelargecapacitypumped-storagepowerplantsinourcountry,theL/Hvaluerespectivelyare:
7.12inGuangzhou.4.12inShisanling,2.40inTianhuangping
A.ismosteconomic
B.isusedtoevaluatetopographicconditionofpowerplant
C.isnotdesirable
D.istheratioofhorizontaldistancebetweenupperandlowreservoir
E.isthebest
Passage7Fuelcells
Fuelcellsaredevicesthatwhenafuelsuchashydrogenorhydrogen-richcompoundsandoxygenaresuppliedtomaterialsarrangedliketheanodeandcathodeofaconventionalbattery,combinetoconvertchemicalenergydirectlyintoelectricalenergy.Unlikeconventionalbatteries.wheretheconversionofchemicaltoelectricalenergyrequiresonlytheclosingofacircuitbetweenthecathodeandanodetoproduceandelectricalcurrent,
(1).Thesecellsrequirethefuelandoxygenthatwillproducethechemicalreactionsthatproduceanelectrical0utout.Fuelcellshavebeenmadethatwillsupplypowerinthemegawattrange,and
(2).Suchcellsarenotyetwidelyusedonpowersystems,but(3)tosupplyfuelcellpowertoisolatedloadsAsthevoltageoutputofacellisintheorderoflto2.5V,(4)andpoweroutputinrangesthatarenormallyrequired.Invertersareusedto(5)whenandACoutputisdesired.
A.furtherdevelopmentisunderway
B.thereisnostoragecapacityinafuelcell
C.manycellsareoperatedinseriestoobtainvoltages
D.supplyalternatingcurrentfromfuelcells
E.astheyarebeingdevelopedtherehavebeensomeapplications
Passage8SubstationspaceintotheDigitalAge
Substationsconstitutethemainpartofpowertransmissionanddistributioninapowergrid.Thesubstations
(1),withtheresponsibilityfortheelectricpowertransmissionanddistributioninthegrid.Overmorethanadecadeofdevelopment,
(2).Intherebuildingandconstructingofpowergridinruralandurbanareas,automationtechnologyisnotonlyusedinlow-voltagesubstationstorealizeunattendedoperation,butalsointhe220kVandaboveextra-voltagesubstations,thusgreatlyenhancingthelevelofmodernizationofpowergridconstruction,strengtheningthepowertransmissionanddistributionandthepossibilityofpowergriddispatchingandreducingthetotalcostofsubstationconstruction,(3).However,thedevelopmentoftechnologyisnever-ending,andtheincreasingmaturationoftechnologylikeintelligentswitches,photoelectriccurrentandvoltagetransformers,onlineconditionmonitoringofprimaryequipments,(4),aswellasthedevelopmentandapplicationofhigh-speednetworkinreal-timesystem,isboundtohaveaprofoundimpactupontheexistingsubstationautomationtechnology,and(5)isabouttoemerge.
A.substationautomationtechnologyhasreachedacertainlevel
B.simulationtrainingtechnologyforsubstationoperation
C.composedofalargenumberofprimaryandsecondaryequipments
D.afull-digitalautomationsystem
E.allofwhichhasbecomeanindisputablefact
Passage9OvercomingtheProblemofWaste
ManylargecitiesareanythingbutbeautifulStreetsarelitteredwithtrash.Inthistrash,however,
(1).
Ifpeoplewanttosolvetheproblemofwaste,
(2).Theymustworkoutwaysofmakinguseofgoodthingswhicharejustthrownawayaswaste.Whenacargetstooold,itmaynotrim
anymore.Butifthemetalthatthecarwasmadeofisstillgood,(3).Whenabottleisempty,itgoesoutinthetrash.Butbottleglasscanbegroundintosandandusedtopavestreets.Besides,garbagefromfoodcanbechangedintofertilizer.Butfirstyouhavetopickoutalltheglassandmetal.
Furthermore,garbagecanalsobeagoodsourceformakingbuildingblocks,whicharethencoveredwithconcrete.Now,(4).Someday,peoplewillwatchfilmsinagreatcinemawhichhasbeenbuiltoutofgarbageFuturebuildings,roads,andcitiesmaybemadefromgarbage.Butsofar,(5).
A.thereisnotimetobelost
B.buildingbeautifulcities