資源描述：
《潮流計(jì)算原理.doc》由會(huì)員上傳分享，免費(fèi)在線閱讀，更多相關(guān)內(nèi)容在教育資源-天天文庫。
1、LOADFLOWWhatisthepurposeofaloadflowstudy?·Tocalculatebusvoltagelevelstocomparetoequipmentratings.·Tocalculatebranchcurrentflowstocomparetoequipmentratings.Areelectricalengineersrequiredtoperformaloadflowstudy?·Yes,perNECArticles210.19forBranchCircuitsand215.2forFeeders.Botharticlesspecifyvoltagedrop
2、limits.·NRCrequiresloadflowstudiestoverifysystemperformance.Whataregoodreferencesforengineersperformingloadflowstudies?·IEEEStd141-1993,IEEERecommendedPracticeforElectricPowerDistributionforIndustrialPlants(IEEERedBook).·IEEEStd399-1997,IEEERecommendedPracticeforIndustrialandCommercialPowerSystemsAn
3、alysis(IEEEBrownBook).LoadModels·ConstantkVAModel–LoadkVAvariesbyV0–examplemotorrunning·ConstantIModel–LoadkVAvariesbyV1–exampleballastlighting,welding·ConstantZModel–LoadkVAvariesbyV2–examplemotorstarting,heater,capacitorSourceModels·PV–VoltageControlledBus,typicalgenerator·PQ–NonvoltageControlledB
4、us,usedwhenstudyingaspecificloadingconditionofagenerator,oraninductiongenerator.·SB–SwingBus,typicalutilitytieNote,loadflowstudiesrequireatleastoneswingbusinthenetwork.Utilitytiesbydefault,areswingbuses.Fig.1.Generatorreactivecapabilitycurve.WhatcantheyoudoifyoudonothaveaReactiveCapabilityCurve?What
5、directioniswattandvarflowforamachineoperatinginlag?Lead?Fig.2.Inductionmotor/generatordatasheet–datagivenasmotor.Fig.3.Inductionmotor/generatordatasheet–datagivenasgenerator.ScheduledP-QSetpointsPandQ:P=2237kWS=kW/pf=2237/0.90=2486kVAQ=(S2–P2)1/2=(24862–22372)1/2=1084kVARCalculationMethodAssumptions
6、Description/ConditionAssumptionPowerSystem3-phase&balancedFrequencyConstantNeutralCurrentzeroAllLoadsKVAc,Ic,ZcAllLoadSourcesPV,PQ,SBSolutionMethodBusvoltagesnotloopcurrentequationsTorunastudyAlwayscheck“SourceImpedance”Alwayscheck“Exact”Ifthesystemwasdevelopedwithdiscretecomponentsandthedemandloadl
7、ibrarywasneverreferenced,stayontheleftside.Check“1stLevelDemand”ifBHPswereentered.Check“ConnectedLoad”ifstudyingloadsrunningatnameplate.IfyoudefinedloadsreferencingtheDemandLoadLibrarystayontherightsi
