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1、BriefIntroductiontoTheElectricPowerSystemPart1MinimumelectricpowersystemAminimumelectricpowersystemisshowninFig.1-1,thesystemconsistsofanenergysource,aprimemover,agenerator,andaload.Theenergysourcemaybecoal,gas,oroilburnedinafurnacetoheatwaterandgeneratesteaminaboiler;itmaybefissionablematerialwhic
2、h,inanuclearreactor,willheatwatertoproducesteam;itmaybewaterinapondatanelevationabovethegeneratingstation;oritmaybeoilorgasburnedinaninternalcombustionengine.Theprimemovermaybeasteam-driventurbine,ahydraulicturbineorwaterwheel,oraninternalcombustionengine.Eachoneoftheseprimemovershastheabilitytocon
3、vertenergyintheformofheat,fallingwater,orfuelintorotationofashaft,whichinturnwilldrivethegenerator.Theelectricalloadonthegeneratormaybelights,motors,heaters,orotherdevices,aloneorincombination.Probablytheloadwillvaryfromminutetominuteasdifferentdemandsoccur.Thecontrolsystemfunctions(are)tokeepthesp
4、eedofthemachinessubstantiallyconstantandthevoltagewithinprescribedlimits,eventhoughtheloadmaychange.Tomeettheseloadconditions,itisnecessaryforfuelinputtochange,fortheprimemoverinputtovary,andfortorqueontheshaftfromtheprimemovertochangeinorderthatthegeneratormaybekeptatconstantspeed.Inaddition,thefi
5、eldcurrenttothegeneratormustbeadjustedtomaintainconstantoutputvoltage.The10controlsystemmayincludeamanstationedinthepowerplantwhowatchesasetofmetersonthegeneratoroutputterminalsandmakesthenecessaryadjustmentsmanually.Inamodernstation,thecontrolsystemisaservomechanismthatsensesgenerator-outputcondit
6、ionsandautomaticallymakesthenecessarychangesinenergyinputandfieldcurrenttoholdtheelectricaloutputwithincertainspecifications..Part2MoreComplicatedSystemsInmostsituationstheloadisnotdirectlyconnectedtothegeneratorterminals.Morecommonlytheloadissomedistancefromthegenerator,requiringapowerlineconnecti
7、ngthem.Itisdesirabletokeeptheelectricpowersupplyattheloadwithinspecifications.However,thecontrolsarenearthegenerator,whichmaybeinanotherbuilding,perhapsseveralmilesaway.Ifthedistancefromthegeneratortotheloa