利用复数储能设备以强健电力系统

233AutonomousDispersedControltoEnergyStorageFacilitiesfortheEnhancementofSystemStability利用複數儲能設備以強健電力系統穩定度之自律分散型控制Chung-NengHuang黃崇能國立台北科技大學車輛工程系AbstractInrecentyears,owingtoohighlymeshednetworkandtheincreasinginterestinwholesalewheelingalternativesopentothird-partygenerations,theproblemofsysteminstabilitygrowsintoaseriousmatter.Thispaperproposesanautonomousdispersedcontrolconceptionofmultipleenergystoragefacilities(ESFs)toalleviatetheshort-termdisturbanceforstabilityenhancement.Intheproposal,eachindividualESFisonlysubjectedtoasimpleruletodeterminethecharge/dischargeactions.Here,theareacontrolerror(ACE)istakenintoaccountthecontrolinamulti-machinesystem.Additionally,theautomaticgenerationcontrol(AGC)asspeedgovernorisalsoconsidered.Consequently,thecontrolresultsareconsistentwithreality.Sincethescenarioisparticularinterestingtothecaseintheloopnetworks,theWSCCthree-machinenine-bussystemistakenasastudyexampletoconfirmtheappropriatenessoftheproposal.Keywords:SystemStability,AutonomousDispersedControl,andEnergyStorageFacility.AutonomousDispersedControltoEnergyStorageFacilitiesfortheEnhancementofSystemStability1234摘要由於電力產業的開放競爭及輸電網路之高度密集化的結果，造成近年來系統穩定性問題日驅嚴重。為有效解除此一問題，故本文提出一儲能設備群之自律分散控制法來消除系統因不平衡所產生之干擾以增強系統穩定。在此控制規則下，各個分佈在系統中的儲能設備僅須依其區域性資訊－亦即檢測連接線路潮流的大小來決定充放電的動作即可。此外,自動發電控制如調速機等控制功能亦納入在多機系統的控制過程中以維持控制結果的客觀性。因為在開放性的輸電環境中將更能彰顯出此控制概念的效果，故本文將透過WSCC之3機9匯流排的輸電系統來驗證其有效性。關鍵詞：電力系統穩定度、自律分散型控制、儲能設備投稿受理時間:92年10月15日審查通過時間:93年1月2日I.IntroductionForthereasonsofsystemrestructuringandopentransmissionaccess,theregionalpowertransfersvaryoverawiderange.Consequently,therearemoreandmorepowertransactionsaredealtviathetransmissionsystem.However,thecapacityofsystemsecurityisconstrainedbyphysicallimitsandreliabilityrequirements[1-2].Nonetheless,manyconcerningutilitiesofelectricpowerdevotemultitudeofeffortandcapitaltoenhancepowersysteminasufficientrobustforsurvivingacascadingdisturbanceinaheavydemand,theinterconnectednetworkstillsufferfromwidespreadandlengthyblackouts[3-5].Aswellknownasabovelesson,theimpactsofapowerdisturbanceoccurringinanywhereofthesystem,notonlycausesinternalfrequencyofthesysteminperturbationbutalsopossiblyinfluenceneighboringsystemstobeinstableviatielines[6].Inordertoalleviatesuchapropagatingdisturbancefromonesystemtoanother,thispaperpresentsapossiblesolutiontothisproblembyintroducinganautonomousdispersedcontrolconceptiononmultipleESFstoalleviatetheshort-termdisturbancefortheenhancementofsystemstability[7-8].However,alargenumberofsystemdataandheavycomputationsarealwaysneededforcarryingouttheaboveproposals.Moreover,suchthepatternsofcentralcontrolarelackofflexibilityfortheextensionfromthelocalareastointerconnectedsystem.2臺北科技大學學報第三十七之一期235Si,Sj,Sk:EnergyStorageFacilityΔPD:InjectionPowerDisturbanceFig.1.ImaginationofESFControlSystemInthispaper,theimaginationofproposedconceptionisshowninFig.1.EachtielinewhichconnectswithtwosystemsisinstalledanESFinitsbothterminals.ThefunctionofeachESFcanbeconsideredasapowerbuffertoabsorbtheflowdeviationofthetielineasACEresultingfromadisturbanceinasystem.Bytheproposedcontrol,ACEofeachsystemcanbesubsidedtobeminimumandstabilizesystemoscillation.Furthermore,sincetheproposedcontrolisonlybasedonthelocalinformationofanarea,itispossibletoextendthecontrolscaletoaninterconnectedsystem.Inordertoperformtheparticularinterestingofproposedconceptiontothecaseintheloopnetworks,theWSCCthree-machinenine-bussystemistakenasastudyexampletoconfirmtheappropriatenessandeffectivenessofthecontrol.II.ProposedControlSchemeThoserolessuchasACE,tie-linebiascontrol(TBC),andspeedgovernorsaswellasAGCwhichplayintheproposedcontrolaredescribedasfollowing:2.1AGCControl[9]Forsupplementarycontrolofinterconnectedsystem,atthefistobservingtheperformanceofspeedcontrolonly.Sincetheinternalgenerationofapowersystemisresponsibletomatchitsinternalloadrequirements,thecontrolfunctionisconsideredtobeindependentfromadjacentsystems.AninterestingobservationonpowerandspeedcorrelationofaspeedgovernorsofarasknownasthefeatureofdroopRwhichmakesthesystemselfregulatetosomeextent.Thedroopisdefinedas;DroopmiiPfR(1)Notethat,theslopingnatureofRianincreasingPmacceleratestherotorofgeneratorandattemptstoraisethesystemfrequencyf.ThequantitydroopisaspeeddroopexpressedinHz/per-unitmegawatts.Now,consideringthedynamicsofrotorinertiawithspeedgovernorcontrol,thecorrelationbetweenaprimemoverpowerandtheoutputpowerofageneratorcanbeexpressedasSystemiSiSjXijΔPDSystemjSystemkXikXjkSkΔPijΔPjkΔPkiAutonomousDispersedControltoEnergyStorageFacilitiesfortheEnhancementofSystemStability3236dtdfHRPPiieimi0)2((2.a))2('0'iiiieimifdtdfHRfPP(2.b)iiiieimiRffdtdHPP2(2.c)Pmi:mechanicaloutputpowerofunitiinpu.Pei:generatoroutputpowerofunitiinpu..Hi:inertiaconstantforunitiinS.t=timeinS.)(2'0iffwhere,0'fffiifrequencydeviationofuniti.Consequently,foracontrolareawherengeneratorsexist,Eq.(1)mayberewrittenasniininiieinimifRfdtdHPP1111)1()2(RffdtdHPPem2(3)nimimPP1:totalprimemoveroutputinanarea.nieiePP1:totalelectricoutputinanarea.niiHH1:total