资源描述:
《Control and Protection of Multi-DER Microgrids》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、ControlandProtectionofMulti-DERMicrogridsbyAmirHosseinEtemadiAdissertationsubmittedinconformitywiththerequirementsforthedegreeofDoctorofPhilosophyGraduateDepartmentofElectricalandComputerEngineeringUniversityofTorontoCopyrightc2012byAmirHosseinEtemadiAbstractCont
2、rolandProtectionofMulti-DERMicrogridsAmirHosseinEtemadiDoctorofPhilosophyGraduateDepartmentofElectricalandComputerEngineeringUniversityofToronto2012Thisdissertationproposesapowermanagementandcontrolstrategyforislandedmicrogrids,whichconsistofmultipleelectronicall
3、y-interfaceddistributedenergyresource(DER)units,toachieveaprescribedloadsharingscheme.Thisstrategyprovidesi)apowermanagementsystemtospecifyvoltagesetpointsbasedonaclassicalpowerflowanalysis;2)DERlocalcontrollers,designedbasedonarobust,decentralized,servomechanisma
4、pproach,totrackthesetpoints;and3)afrequencycontrolandsynchronizationscheme.Thisstrategyisthengeneralizedtoincorporatebothpower-controlledandvoltage-controlledDERunits.Sincethevoltage-controlledDERunitsdonotuseinnercurrentcontrolloops,theyarevulnerabletoovercurren
5、t/overloadtransientssubsequenttosystemseveredisturbances,e.g.,faultsandoverloadingconditions.TopreventDERunittrip-outordamageundertheseconditions,anovercurrent/overloadprotectionschemeisproposedthatdetectsmicrogridabnormalconditions,modifiestheterminalvoltageofthe
6、correspondingVSCtolimitDERunitoutputcurrent/powerwithinthepermissiblerange,andrestoresvoltagecontrollerssubsequently.Undercertaincircumstances,e.g.,microgridislandingandcommunicationfailure,thereisaneedtoswitchfromanactivetoalatentmicrogridcontroller.Tominimizeth
7、eresultanttransients,controltransitionshouldbeperformedsmoothly.Fortheaforementionedtwocircumstances,twosmoothcontroltransitiontechniques,basedon1)anobserverand2)anauxiliarytrackingcontroller,areproposedtoachieveasmoothcontroltransition.Atypicalmicrogridsystemtha
8、tadoptstheproposedstrategyisinvestigated.Themicrogriddynamicsareinvestigatedbasedoneigenvaluesensitivityandrobustanalysisstudiestoevaluatetheperformanceofthecl