Instantaneous Active and ReactivePower Measuring Method in Three Phase Power System.docx
- 文档编号:23045769
- 上传时间:2023-04-30
- 格式:DOCX
- 页数:14
- 大小:343.55KB
Instantaneous Active and ReactivePower Measuring Method in Three Phase Power System.docx
《Instantaneous Active and ReactivePower Measuring Method in Three Phase Power System.docx》由会员分享,可在线阅读,更多相关《Instantaneous Active and ReactivePower Measuring Method in Three Phase Power System.docx(14页珍藏版)》请在冰豆网上搜索。
InstantaneousActiveandReactivePowerMeasuringMethodinThreePhasePowerSystem
InstantaneousActiveandReactivePowerMeasuringMethodinThreePhasePowerSystem
A.TAHRI,A.DRAOU
AppliedPowerElectronicsLaboratory,DepartmentofElectrotechnics,
UniversityofSciencesandTechnologyofOran
BP1505ElMnaouar(31000Oran),ALGERIA,Fax:
+213–41–421581
Contactauthor:
Dr.AzeddineDraou,SeniormemberIEEE,Email:
adraou@
Abstract
Thispaperdescribesanelectronicmeansofmeasuringtheinstantaneousactiveandreactivepowerabsorbedbyanyelectricalequipment.ThemeasurementsarebasedontheClark(α-β)andPark(d-q)transformations.ThesystemisusefultoteachelectricalmachinesinPark’scoordinatesanditallowsalsothestudyandcontrolofsomepowerelectronicsconvertersthatareconnectedtothreephasepowernetwork,suchasstaticVARcompensator.Theprincipleofthemeasuringmethodoftheactiveandreactivepowerisdescribed,andanalyzedfordifferenttests.Theeffectivenessoftheproposedmeasuringmethodisconfirmedbyexperimentalinvestigationemployingatestsystem.
Keywords
Activepower,Reactivepower,SVC,ClarkandPark,EPROM
Introduction
Uptonow,thereactivepowerdoesn’treallyhaveaphysicalsignificance,butitremainsrecognizedasanessentialfactorintheconceptionandtheefficientoperatingofACelectricnetwork[1].TheapplicationofClark(α-β)andPark(d-q)transformstothreephasesysteminordertocalculatetheinstantaneousactiveandreactivepowerisausefultoolforstudyandanalysisofmanyelectricalsystems[2].Therearemanyindustrialapplicationsthatrequiretheknowledgeoftheinstantaneousvalueoftheactiveandreactivepower.Infact,theyareusedtomanagetheeconomicalaspectoftheirsystem[1,3,4].
Theinstantaneousactiveandreactivepowersarealsousedinthecontrolofconvertersconnectedtoelectricnetwork[5].Theseconverterscancontroltheflowofactiveandreactivepowerinthepowersystemtoimprovevoltageregulation,andincreasingtransientstabilitymargin[4,5].
Inthispaper,aninexpensiveelectroniccircuitthatcalculateClark(α-β),Park(d-q)componentsandtheinstantaneousactiveandreactivepowerforthreephaseACsystemispresentedanddiscussedthoroughly.
Theeffectivenessoftheproposedelectronicmethodthatcalculatestheinstantaneousactiveandreactivecurrentsandpowerisconfirmedbyexperimentalresultsthroughalaboratoryprototype.
TheoreticalAnalysis
α-βtransformation
Voltagesandcurrentscanbetransformedfromabcsystemtoα-βcoordinatesasfollows,whereXdenotesvoltageorcurrent:
(1)
d-qtransformation
Fromα-βtransformationthed-qcoordinatesaregivenby:
(2)
Activeandreactivepower
Theactiveandreactivepowerforthreephasebalancedsystemcanbewrittenind-qcoordinatesasfollows,where
and
arethevoltagesandcurrentsind-qcoordinates:
(3)
ProposedMeasuringSystem
Generaldescription
Theblockdiagramoftheproposedmeasuringsystemispresentedinfig.1.Thewholesystemisdividedinthreesubsystemsconnectedincascade. Thefunctionofsubsystem1istosynchronizeallofthesystemtotheACmainsusingPLLandtogeneratetheadequateaddressestogeneratesineandcosinefunctionswhicharestoredintwoEPROMS.
Inthesubsystem2,themeasuredvoltagesandcurrentsaretransformedfromabctoClarkandParkcoordinates. Andinthethirdsubsystemtheinstantaneousactiveandreactivepowerarecalculated.
Detaileddescription
Subsystem1:
Subsystem1isfrequencysynthesizer.Theclockfrequencyis16.16.16.8.50Hz=1.638MHzsynchronizedtotheACmain.Thisclockfrequencyisusedtodrivetheaddressgenerator.Theaddressgeneratoriscomposedoffour74HC161synchronouspre-settablebinarycountersandtwo74HC245buffers.TheaddressesobtainedaresuitabletoreadinparalleltwoEPROMsof
wheresineandcosinefunctionsarestored.Hencetheobtainedaddressgeneratorisshowninfig.2.
Subsystem2:
ThemeasuredvoltagesandcurrentsinabcframearetransformedinClarkandParkcoordinates.TheClarktransformgivenbyequation
(1)isobtainedusingsimpleoperationalamplifiersasshowninfig.3.
Figure1.Proposedmeasurementsystem
Figure2.Addressgenerator
Figure3.ClarktransformCircuit
ParkcoordinatesareobtainedfromClarkcoordinatesbyusingequation
(2).
ThesineandcosinefunctionsgeneratedbytheaddressgeneratorandsynchronizedtotheACmainsareusedtoobtaintheParkcoordinatesbyusingtheanalogmultiplierAD534JDasshowninfig.4.
Figure4.ParktransformCircuit
Subsystem3:
TheinstantaneousactiveandreactivepowercalculatorisalsoobtainedusingtheanalogmultiplierAD534JDasshowninfig.5.
Figure5.Instantaneousactiveandreactivepowercalculator
ExperimentalResults
Toconfirmtheeffectivenessoftheproposedmeasuringmethodofinstantaneousactiveandreactiveunits,someexperimentswerecarriedoutemployingatestsystemwithdifferentloads.Fig.6showsthedirectandquadraturePark’svoltagesoftheACmains.Atransientstartingtestofinductionmotorwascarriedatthelaboratorywiththeproposedsystem.
Fig.7showstheACcurrentabsorbedbyinductionmotorintransientstarting.Fig.8showsthedirectandquadraturecurrentsofinductionmotorstarting.
Theactiveandreactivepowerabsorbedbytheinductionmotorintransientstartingaredepictedinfig.9.Themeasurementsystemwastestedwithinductionmotorwithoutload,itisclearthattheactivepowerabsorbedbythemotorisnegligiblebutthereisalittleamountofreactivepowernecessarytocreatethethreephase rotatingmagneticfieldinthestatoroftheinductionmotor.Anothertestwascarriedoutinthelaboratorywiththreephasesymmetricthyristorrectifier.Fig.10showstheoutputDCvoltageandinputcurrentoftherectifierforthephaseanglecontrolα=80degree.
Fig.11showsthedirectandquadraturecurrentsabsorbedbythethreephasesymmetricrectifierforthephaseanglecontrolα=80degree,andtheactiveandreactivepoweraredepictedinfig.12.
Figure6.DirectandquadraturevoltagesoftheACmains
Figure7.ACcurrentofinductionmotorattransientstarting
Figure8.Directandquadraturecurrentsofinductionmotorintransientstarting
Figure9.Activeandreactivepowerabsorbedbyinductionmotorattransientstarting
Figure10.OutputDCvoltageandinputcurrentofthreephasesymmetricrectifier
withα=80degree
Figure11.Directandquadraturecurrentsofthreephasesymmetricrectifierwithα=80°
Figure12.Activeandreactivepowerofthreephasesymmetricrectifierwithα=80degree
Conclusions
Inthispaperanelectronicmeasurementoftheinstantaneousactiveandreactivepowermethodhasbeenpresented.Theproposedmeasurementsystemhasthoroughlybeentestedinsteadyandtransientstates.Themeasurementmethodcanbeusedtostudydifferentelectricalequipmentinlaboratoryasinductionandsynchronousmachinesandsomeconverters.
Thesteadystateandtransientmeasurementresultsobtainedhaveconfirmedtheapplicabilityoftheproposedschemetodesignasimpleandfastcontrollerforactiveandreactivepowerapplications.
References
1. MillerT.J.E.,ReactivePowerControlinElectricSystems,JohnWileyandSons,Inc.1982.
2. PaapC.G.,SymmetricalComponentsintheTimeDomainandTheirApplicationtoPowerNetworkCalculations,IEEETrans.OnPowerSystems,Vol.15,No.2,May2000.
3. BoisdonC.,DrownG.,Lessystèmesdecompensationstatiquerapidedanslesréseauxindustriels,R.G.E.No.12,Decembre1984.
4. TahriA.,DraouA.,BenghanemM.,PowerStabilityImprovementofPowerUtilitygridusingaNewAdvancedStaticVarCompensator,23rdInternationalTelecommunicationsEnergyConference,INTELEC2001,EdinburghUK,14-18October2001.
5. TahriA.,DraouM.,BenghanemA.,FastCurrentControlStrategyofaPWMInverterusedforStaticVarCompensation,Proceedingsofthe24thAnnualConferenceoftheIEEEIndustrialElectronicsSocietyIECON'98,Vol.1,p.450-455,Aachen-Germany,August31-September4,1998.
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- Instantaneous Active and ReactivePower Measuring Method in Three Phase Power System
链接地址:https://www.bdocx.com/doc/23045769.html