電氣工程及其自動化專業(yè)英語 課件 -Chapter 6：Flexible AC Transmission Systems (FACTS)

目錄Introduction6.1StaticVarCompensator(SVC)6.2UniformPowerFlowController(UPFC) 6.3Bridge-TypeFaultCurrentController(FCC)6.4Chapter6：FlexibleacTransmissionSystems(FACTs)thermal['θ?:m?l]adj.熱的，熱量的thrust[θr?st]n.推力；刺compensator['k?mp?nseit?]n.補償器；自耦變壓器flywheel['flaiwi:l]n.飛輪，慣性輪；調(diào)速輪margin['mɑ:d?in]n.界限；差數(shù)；幅度oscillation[,?si'lei??n]n.振蕩；振動；擺動bulk[b?lk]n.（巨大的）體積，容積；容量，(大)量alleviate[?'li:vieit]vt.減輕，緩和meshed[me?t]adj.網(wǎng)狀的；有網(wǎng)孔的shaft[??ft]n.拍桿；軸turbine['t?:bain,-bin]n.渦輪；渦輪機Anovelstaticvar（）basedonPWMtechnologywasintroduced.compensatortransformercurrenttransformerelectricreactorABCD提交單選題1分Thereareafewtechnicaldifficulties,butIbelieveinthenextfivetotenyearswewillbeinstallingcommercialmarine（）farms.hingewindmillengineturbineABCD提交單選題1分detune[di:'tu:n]vt.使去諧；降低（調(diào)門）collaborative[k?'l?b?r?tiv]adj.合作的，協(xié)作的prototype['pr?ut?taip]n.原型；標(biāo)準(zhǔn)，模范deionize[di:'ai?naiz]vt.除去離子；消電離ambient['?mbi?nt]adj.周圍的；環(huán)繞的；外界的mitigate['mitiɡeit]vt.使緩和，使減輕modularity[,m?dju'l?riti,-d?u-]n.模塊性intertie['int?tai]n.（美）聯(lián)鎖電力網(wǎng)steeply['sti:pli]adv.陡峭地；險峻地perpendicular[,p?:p?n'dikjul?]adj.垂直的，正交的；直立的rectify['rektifai]vt.整流Diodesareelectronicdeviceswhich（）alternatingcurrenttodirectcurrent.alterrectifyboostoptimizeABCD提交單選題1分demonstration

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Three-phasefive-columnvoltagetransformercanbeusedfor()LowvoltageprotectionmeasuringnegativesequencevoltagemeasuringzerosequencevoltageUndervoltagewarningABCD提交單選題1分目錄Introduction6.1StaticVarCompensator(SVC)6.2UniformPowerFlowController(UPFC) 1026.3Bridge-TypeFaultCurrentController(FCC)6.46.1IntroductionTightercontrolofpowerflowandincreaseduseoftransmissioncapacityarekeybenefitsofnewthyristor-basedcontrollers.Apowerlinecanfunctionneareritstopthermalratingifregulatedbyflexibleactransmissionsystemcontrollers.新型晶閘管控制器的主要優(yōu)點是能更準(zhǔn)確地控制潮流和更多地利用傳輸容量。如果采用靈活的交流傳輸系統(tǒng)控制器調(diào)節(jié)，輸電線路可在接近最高允許額定溫度的情況下運行。6.1IntroductionTheelectricutilities’systemsfortransmittinganddistributingpowerareenteringaperiodofchange.Theiroperationisfine-tunedtoanunprecedenteddegree,bytheapplicationofpowerelectronics,microprocessorsandmicroelectronicsingeneral,andcommunications.Thesetechnologieswillmakethetransmissionanddistributionofelectricitymorereliable,morecontrollable,andmoreefficient.電力公司的輸配電系統(tǒng)正在進入一個變革時期。通過電力電子、微處理器和微電子技術(shù)以及通信技術(shù)的應(yīng)用，它們的運行達到了前所未有的精細程度。這些技術(shù)將使電力的輸配更可靠、更可控、更高效。6.1Introduction

ActingfortheUSelectricutilityindustry,theElectricPowerResearchInstitute(EPRI)inPaloAlto,Calif.,hasledthewayinthisareawithseveralthrusts,nottheleastbeingtheflexibleactransmissionsystem,knownintheindustryasFACTS.作為美國電力行業(yè)的代表，位于加州帕洛阿爾托的電力研究所(EPRI)已經(jīng)在這一領(lǐng)域率先推出了幾個項目，其中最重要的是靈活的交流輸電系統(tǒng)，在業(yè)內(nèi)被稱為FACTS。6.1IntroductionPowerelectronicbasedflexibleactransmissionsystem(FACTS)devicesprovideprovensolutionstomeetthesechallenges.Whenusedincombinationwithwideareacontrolsystems(WAMS)itispossibletoincreaseperformancebenefitsfurther.基于電力電子的柔性交流傳輸系統(tǒng)(FACTS)設(shè)備為應(yīng)對這些挑戰(zhàn)提供了成熟的解決方案。當(dāng)與廣域控制系統(tǒng)(WAMS)結(jié)合使用時，可以進一步提高性能效益。6.1IntroductionFACTScontrollerscanbeclassifiedbasedonthepowerelectronictechnologyused.Existinginstallationsthatuseline-commutatedthyristorbasedtechnologiesareeitherStaticVarCompensators(SVC)orThyristorControlledSeriesCompensators(TCSC).FACTS控制器可以根據(jù)所使用的電力電子技術(shù)進行分類。現(xiàn)有的靜止無功補償（SVC）或者可控串聯(lián)補償（TCSC）裝置使用的都是電網(wǎng)換相的晶閘管技術(shù)。6.1IntroductionFACTSdevicescanalsobebasedonvoltagesourceconverters,whichutilizeself-commutateddevicessuchasgateturnoffthyristors(GTO),gatecommutatedthyristors(GCT),orinsulatedgatebipolartransistors(IGBT).FACTS器件還可以基于電壓源變換器，其利用自整流器件，如柵極關(guān)斷晶閘管(GTO)、柵極整流晶閘管(GCT)或絕緣柵雙極晶體管(IGBT)。6.1IntroductionExistingVSC-basedFACTSinstallationsusingcanbecategorizedasStaticSynchronousCompensators(STATCOM),UnifiedPowerControllers(UPFC),andConvertibleStaticCompensators(CSC).現(xiàn)有的基于VSC的FACTS裝置可分為靜止無功發(fā)生器(STATCOM)、統(tǒng)一潮流控制器(UPFC)和轉(zhuǎn)換靜止補償器(CSC)。6.1IntroductionInsomeSTATCOMbehaviorisincludedasasecondarycontroloptionindevicessuchaspowerelectronicinterfacesforwindturbines(suchasthefieldcontrolonaDFIG.orthepowerelectronicinterfaceforaenergystoragesystemsuchasabatteryenergystoragesystem(BESS),asuperconductingmagneticenergystoragesystem(SMES)oraflywheelenergystoragesystem.在某些情況下，STATCOM行為被作為二次側(cè)控制選項包含在設(shè)備中，如風(fēng)力渦輪機的電力電子接口(如DFIG上的現(xiàn)場控制)。或用于電池儲能系統(tǒng)(BESS)、超導(dǎo)磁性儲能系統(tǒng)(SMES)或飛輪儲能系統(tǒng)等儲能系統(tǒng)的電力電子接口。6.1IntroductionVoltagesourceconverterbasedhighvoltagedirectcurrent(VSC-HVDC)transmissionalsoexhibitsdynamicreactivecontrolcapabilitieswhichareutilizedaswell.基于電壓源變換器的高壓直流輸電也表現(xiàn)出動態(tài)無功控制能力。6.1IntroductionTheflexibletransmissionsystemisakintohigh-voltagedcandrelatedthyristordevelopments,designedtoovercomethelimitationsofthepresentmechanicallycontrolledACpowertransmissionsystems.Byusingreliable,high-speedpowerelectroniccontrollers,thetechnologyoffersutilitiesfiveopportunitiestoincreasedefficiency:柔性輸電系統(tǒng)的發(fā)展類似于高壓直流及其相關(guān)的晶閘管技術(shù)，旨在克服目前機械控制的交流輸電系統(tǒng)的局限性。通過使用可靠、高速的電力電子控制器，該技術(shù)提供了五個提高效率的契機:6.1Introduction①Greatercontrolofpower,sothatitflowsontheprescribedtransmissionroutes.②Secureloading(butnotoverloadingoftransmissionlinestolevelsnearertheirthermallimits.③Greaterabilitytotransferpowerbetweencontrolledareas,sothatthegenerationreservemargin-typically18percent-maybereducedto15percentorless.①更強的功率控制，使其在指定的傳輸路線上流動。②確保輸電線路的安全負荷(但不能超載)，使其接近其熱穩(wěn)定極限。③更強的控制區(qū)域之間的電力轉(zhuǎn)移能力，使發(fā)電儲備邊際從通常的18%降至15%或更低。6.1Introduction④Preventionofcascadingoutagesbylimitingtheeffectsoffaultsandequipmentfailure.⑤Dampingofpowersystemoscillations,whichcoulddamageequipmentand/orlimitusabletransmissioncapacity.④通過限制故障和設(shè)備故障的影響來防止級聯(lián)中斷。⑤阻尼可能損壞設(shè)備和/或限制可用的傳輸能力的電力系統(tǒng)振蕩。6.1IntroductionAdvantagesandsavingsmustbeweighedagainstthecostofthepowerelectroniccontrollersrequired.AtaboutUS$50-$100perkilovoltampere(kVA)ratingofthethyristor-basedcontrollers,thetypicalcapitalcostofthesecontrollerscanalreadybeaffordedforsomeutilityapplications.(Roughlyspeaking,thecostperkilovoltamperedecreaseswithanincreaseinthesizeofthecontroller.)電力電子控制器的成本必須權(quán)衡效率和經(jīng)濟效益?；诰чl管的控制器的每千伏安(kVA)額定值約為50-100美元，這些控制器的典型資本成本可以由為一些電力企業(yè)單位承擔(dān)。(一般來說，每千伏安的成本隨著控制器尺寸的增加而降低。)6.1IntroductionTheflexiblesystemowesitstightertransmissioncontroltoitsabilitytomanagetheinterrelatedparametersthatconstraintoday’ssystems,includingseriesimpedance,shuntimpedance,phaseangle,andtheoccurrenceofoscillationsatvariousfrequenciesbelowtheratedfrequency.靈活的系統(tǒng)將其更嚴格的傳輸控制歸功于其管理約束當(dāng)今系統(tǒng)的相關(guān)參數(shù)的能力，包括串聯(lián)阻抗、分流阻抗、相位角以及低于額定頻率的各種頻率的振蕩。6.1IntroductionByaddingtoflexibilityinthisway,thecontrollersenableatransmissionlinetofunctionneareritsthermalrating.Forexample,a500-kVlinemayhavealoadinglimitof1000-2000MWforsafeoperation,butathermallimitof3000MW.通過以這種方式增加靈活性，控制器使傳輸線的功能更接近其額定溫度。例如，為了安全運行，500千伏線路的負載限制為1000-2000兆瓦，但熱極限為3000兆瓦。6.1IntroductionItisoftennotpossiblebothtoovercometheseconstraintsandtomaintaintherequiredsystemreliabilitybyconventionalmechanicalmeansalone,suchastapchangers,phaseshifters,andswitchedcapacitorsandreactors(inductors).Granted,mechanicalcontrollersareonthewholelessexpensive,buttheyincreasinglyneedtobesupplementedbyrapidlyrespondingpowerelectronicscontrollers.通常不可能既克服這些限制，又僅通過傳統(tǒng)的機械手段(如分接開關(guān)、移相器、開關(guān)電容器和電抗器(電感器))來維持所需的系統(tǒng)可靠性。誠然，機械投切控制器總體上更便宜，但它們越來越需要快速響應(yīng)的電力電子控制器作為輔助補充。6.1IntroductionThenewtechnologyisnotasingle,highpowerelectroniccontroller,butratheracollectionofcontrollers,whichcanbeappliedindividuallyorcollectivelyinaspecificpowersystemtocontrolthefiveinterrelatedfunctionsalreadymentioned.新技術(shù)不是單一的高功率電子控制器，而是控制器的集合，它們可以單獨或集體應(yīng)用于特定的電力系統(tǒng)中，以控制前面提到的五種相互關(guān)聯(lián)的功能。6.1IntroductionThethyristoristheirbasicelement,justasthetransistoristhebasicelementforawholevarietyofmicroelectroniccircuits.Becauseallcontrollersfortheflexibletransmissionsystemareapplicationsofsimilartechnology,theirusewilleventuallybenefitfromvolumeproductionandfurtherdevelopmentofhigh-powerelectronics.晶閘管是它們的基本元件，正如晶體管是各種微電子電路的基本元件一樣。由于柔性傳動系統(tǒng)的所有控制器都是類似技術(shù)的應(yīng)用，因此它們的使用最終將受益于大批量生產(chǎn)和大功率電子設(shè)備的進一步發(fā)展。6.1IntroductionElectricpowernetworksintegrategenerationandloadcenterswithineachutilitysystemandsharepowerwithvastregionalgridsthroughinterconnectionsamongneighboringsystems.Thepurposeofthisistotakeadvantageofthediversityofloads,changesinpeakdemandduetoweatherandtimedifferences,theavailabilityofdifferentgenerationreservesinvariousgeographicregions,power-sharingarrangementsamongutilities,shiftsinfuelprices,regulatorychanges,andotherdiscrepancies.電力網(wǎng)絡(luò)將每個電力系統(tǒng)內(nèi)的發(fā)電和負荷中心整合在一起，并通過相鄰系統(tǒng)之間的互連與廣大的區(qū)域電網(wǎng)共享電力。這樣做的目的是利用負荷的多樣性、因天氣和時差引起的高峰需求的變化、不同地理區(qū)域的不同發(fā)電儲備的可用性、電力公司之間的電力共享安排、燃料價格的變化、監(jiān)管變化和其他差異。6.1IntroductionByfacilitatingbulkpowertransfers,theseinterconnectednetworkshelpminimizetheneedtoenlargepowerplantsandenableneighboringutilitiesandregionstobuyandsellpoweramongthemselves.Thus,theelectricpowertransmissionnetworkisessentialforreliable,low-costpower.Conversely,inadequatetransmissionwillresultinlessreliable,morecostly.通過促進大規(guī)模電力傳輸，這些相互連接的電網(wǎng)有助于最大限度地減少擴建發(fā)電廠的需要，并使鄰近的電網(wǎng)和地區(qū)能夠相互買賣電力。因此，電力傳輸網(wǎng)絡(luò)對于可靠、低成本的電力至關(guān)重要。相反，傳輸不足將導(dǎo)致可靠性降低，成本增加。6.1IntroductionThedemandsplacedonthetransmissionnetworkhavegrowninrecentyears,andwillgoongrowing,bothbecausenon-utilitygenerators(NUGs)areenteringthemarketinincreasingnumbersandbecausecompetitionamongtheutilitiesthemselveshasheightened.近年來，對輸電網(wǎng)的需求不斷增長，而且還將繼續(xù)增長，這不僅是因為越來越多的自用發(fā)電機(UNGs)進入市場，而且因為電力公司之間的競爭加劇。6.1IntroductionMakingmattersworseistheextremedifficultyofacquiringnewrights-of-way.Althoughtheflexibletransmissiontechnologycanalleviatesomeofthesepressures,itmustbestressedthatformuchcapacityexpansion,buildingorupgradingoflineswithoutresortingtoflexibletransmissiontechnologywillstillbethemosteconomicalwaytogo.并且獲得新的許可極其困難。雖然柔性傳輸技術(shù)可以緩解這些壓力，但必須強調(diào)的是，對于大量的容量擴展，不采用柔性傳輸技術(shù)的線路建設(shè)或升級仍然是最經(jīng)濟的方式。6.1IntroductionWhatisofmostinteresttothetransmissionplanneristhenewoptionsopenedupbythetechnologyforcontrollingpowerandenhancingtheusablecapacityofpresentlinesthroughvoltageandcurrentupgrading,impedancemodification,andphaseangleregulation.輸電規(guī)劃人員最感興趣的是，通過電壓和電流升級、阻抗修改和相角調(diào)節(jié)，該技術(shù)為控制功率和提高現(xiàn)有線路的可用容量開辟了新的選擇。6.1IntroductionAwell-knownformulastatesthatthepowerflowbetweentwopointsalongatransmissionlineisequaltotheproductofthevoltagesatthesepoints,timesthesineofthedifferencebetweentheirphaseangles,alldividedbythetransmissionline’sreactancebetweenthetwopoints.一個眾所周知的公式表明，沿傳輸線兩點之間的功率流等于兩點電壓的乘積，乘以它們相角差的正弦值，再除以兩點之間傳輸線的電抗。6.1IntroductionTounderstandthefreeflowofpower,consideranelementarycaseinwhichtwogeneratorsaresendingpowertoaloadcenterthroughanetworkconsistingofthreelinesinameshedconnection[Fig.6.1].為了理解電力的自由流動，考慮一個基本的情況，兩臺發(fā)電機通過一個由三條線組成的網(wǎng)格連接網(wǎng)絡(luò)向負荷中心供電[圖6.1]。6.1IntroductionFig.6.1freeflowofpowerinsimplestructuregrid圖6.1簡單結(jié)構(gòu)網(wǎng)格中功率的自由流動6.1IntroductionThelinesAB,BC,andAChavecontinuousratingsof1000Mw,1250Mw,and2000Mwrespectivelywithemergencyratingsoftwicethosefigures.Ifonegeneratorisratedat2000MWandtheotherat1000Mw,atotalof3000Mwwouldbedeliveredtotheloadcenter.Fortheimpedancesshown,thethreelinesshouldcarry600,1600,and1400Mw,respectively.Suchasituationwouldoverloadoneline.AB、BC和AC線路的連續(xù)額定功率分別為1000MW、1250MW和2000MW，應(yīng)急額定功率是這些數(shù)字的兩倍。如果一臺發(fā)電機的額定功率為2000MW，另一臺發(fā)電機的額定功率為1000MW，則總共將向負荷中心輸送3000MW的電力。對于所示的阻抗，三條線路應(yīng)分別承載600、1600和1400MW。這種情況會使一條線路超負荷。6.1IntroductionPower,inshort,flowsinaccordancewithtransmissionlineimpedancesthatbearnodirectrelationshiptotransmissionownership,contracts,orthermallimits.Thedifferencebetweenthefree-flowpathandthecontractpathiscalled“l(fā)oopflow,”andisusuallycharacterizedbyacirculationofpowerthatleavestheavailablecapacityunderutilized.簡而言之，電力根據(jù)輸電線路阻抗流動，與輸電所有權(quán)、合同或熱限制沒有直接關(guān)系。自由流動路徑和合同路徑之間的差異稱為"環(huán)流"，通常表現(xiàn)為電力循環(huán)，導(dǎo)致可用容量利用不足。6.1IntroductionIf,however,acapacitorwhosereactanceis-5Ωatthesynchronousfrequencyisinsertedinoneline[Fig.1,topright],itreducestheline’simpedancefrom10Ωto5Ω,sothatpowerflowthroughthelineswillbe250,1250,and1750Mwrespectively.然而，如果在一條線路上插入一個在同步頻率下電抗為-5Ω的電容器[圖1，右上]，則線路的阻抗從10Ω減小到5Ω，從而流經(jīng)線路的功率將分別為250、1250和1750MW。6.1IntroductionItisclearthatiftheseriescapacitorisadjustable,thenotherpower-flowlevelsmayberealizedinaccordancewiththeownership,contract,andthermallimitations.Thiscapacitorcouldbemodularandmechanicallyswitched.butthenumberofoperationswouldbeseverelylimitedbyweironthemechanicalcomponents.顯然，如果串聯(lián)電容器是可調(diào)的，那么就可以根據(jù)所有權(quán)、合同和熱限制實現(xiàn)其他功率流水平。這種電容器可以采用模塊化和機械切換的方式。但機械部件上的氣動觸頭會嚴重限制操作次數(shù)。6.1IntroductionOthercomplicationsmayarise.Aseriescapacitorinalinemayleadtosub-synchronousresonance,typicallyat15-30Hz.Thisresonanceoccurswhenthemechanicalresonancefrequencyoftheshaftofthegeneratorcoincideswith60Hzminustheelectricalresonancefrequencyofthecapacitorinserieswiththetotalsystemimpedance.其他問題也可能出現(xiàn)。線路中的串聯(lián)電容可能導(dǎo)致次同步諧振，通常為15-30Hz。當(dāng)發(fā)電機軸的機械諧振頻率等于電網(wǎng)的60Hz減去串聯(lián)補償產(chǎn)生的電磁諧振頻率時，就會發(fā)生這種諧振。6.1IntroductionIfsuchresonancepersists,itsoondamagestheshaft.Furthermore,whiletheoutageofonelineisforcingotherlinestooperateattheiremergencyratingsandcarryhigherloads,power-flowoscillationsatlowfrequency(typically1-2Hz)maycausegeneratorstolosesynchronism,perhapspromptingthesystem’scollapse.如果這種共振持續(xù)下去，很快就會損壞軸。此外，當(dāng)一條線路的中斷迫使其他線路以其緊急額定運行并承載更高的負載時，低頻(通常為1-2Hz)的潮流振蕩可能會導(dǎo)致發(fā)電機失去同步，可能會導(dǎo)致系統(tǒng)崩潰。6.1IntroductionIftheseriescapacitoristhyristorcontrolled,itcanbeoperatedasoftenasrequiredandcanbemodulatedsorapidlytodampanysub-synchronousresonanceconditions,aswellaslow-frequencyoscillationsinpowerflow,andallowthetransmissionsystemtogofromonesteadystateconditiontoanotherwithoutdamagetoageneratorshaftorthecollapseofthesystem.如果串聯(lián)電容器由晶閘管控制，則可根據(jù)需要頻繁運行，并可快速調(diào)制，以抑制任何次同步諧振情況以及功率流中的低頻振蕩，并使輸電系統(tǒng)從一種穩(wěn)定狀態(tài)進入另一種穩(wěn)定狀態(tài)，而不會損壞發(fā)電機軸或?qū)е孪到y(tǒng)崩潰。6.1IntroductionInotherwords,athyristor-controlledseriescapacitorcangreatlyenhancethestabilityofthenet-work.Moreoftenthannot,though,itismostpracticalforpartoftheseriescompensationtobemechanicallycontrolledandpartthyristorcontrolled,soastocounterthesystemcontraintsatleastcost.換句話說，晶閘管控制的串聯(lián)電容器可以大大提高網(wǎng)絡(luò)結(jié)構(gòu)的穩(wěn)定性。不過，最實際的做法往往是部分串聯(lián)補償由機械控制，部分由晶閘管控制，以便以最低成本應(yīng)對系統(tǒng)限制。6.1IntroductionSimilarresultsmaybeobtainedbyincreasingtheimpedanceofoneofthelinesinthesamemeshedconfigurationbyinsertinga7Ωreactor(inductor)inserieswiththeline[Fig.6.1].Again,aseriesinductorthatispartlymechanicallyandpartlythyristorcontrolledcouldservetoadjustthesteady-statepowerflowsaswellasdampunwantedoscillations.通過與線路串聯(lián)插入7Ω電抗器(電感)來增加同一網(wǎng)格結(jié)構(gòu)下其中一條線路的阻抗，也可以得到類似的結(jié)果[圖6.1]。同樣，部分機械和部分晶閘管控制的串聯(lián)電感可以用來調(diào)節(jié)穩(wěn)態(tài)功率流以及阻尼不必要的振蕩。6.1IntroductionIneithercase,athyristor-controlledphaseangleregulatorcouldbeinstalledinsteadofaseriescapacitororaseriesreactorinanyofthethreelinestoservethesamepurpose.Notethatneithertheinductornorthephaseangleregulatorcontributestosubsynchronousresonance.在任何一種情況下，一個可控硅控制的相角調(diào)節(jié)器可以代替串聯(lián)電容器或串聯(lián)電抗器安裝在任何三條線路，以達到相同的目的。注意，無論是電感器還是相角調(diào)節(jié)器都不會產(chǎn)生次同步諧振。6.1IntroductionAtlowerrightinFig.6.1,theregulatorisinstalledinthethirdlinetoreducethetotalphaseangledifferencealongthelinefrom8.5degreesto4.2degrees.Asbefore,acombinationofmechanicalandthyristorcontrolinthephaseangleregulatormayminimizecost.在圖6.1右下方，調(diào)節(jié)器安裝在第三條線路上，將沿線的總相角差從8.5度減小到4.2度。如前所述，在相角調(diào)節(jié)器中結(jié)合使用機械控制和晶閘管控制可最大限度地降低成本。6.1IntroductionSeveralcontrollersarepresentlybeingevaluatedforflexibletransmissionsystems,whileothershavebeenconceptualizedbutnotyetdeveloped.Whatmightbecalledthefirstgenerationofcontrollersincludestwothyristor-basedsystemsthathavebeenusedinsomeutilitysystemsforseveralyears.目前正在對用于柔性輸電系統(tǒng)的幾種控制器進行評估，而其他控制器雖已概念化，但尚未開發(fā)。第一代控制器包括兩個基于晶閘管的系統(tǒng)，已在一些電力系統(tǒng)中使用了數(shù)年。6.1IntroductionThefirst,astaticvarcompensator(SVC)hasbeenusedsincethel970s.Itaddressestheproblemofkeepingsteady-stateanddynamicvoltageswithinbounds,andhassomeabilitytocontrolstability,butnonetocontrolactivepowerflow.TheSVCusesthyristorvalvestoaddorremoveshunt-connectedreactorsand/orcapacitorsrapidly,oftenincoordinationwithmechanicallycontrolledreactorsand/orcapacitors.第一種是靜態(tài)無功補償器(SVC)，自20世紀(jì)70年代以來一直使用。它解決了保持穩(wěn)態(tài)電壓和動態(tài)電壓在一定范圍內(nèi)的問題，具有一定的穩(wěn)定控制能力，但沒有控制有功潮流的能力。SVC使用晶閘管閥快速投入或切除并聯(lián)電抗器和/或電容器，通常與機械控制的電抗器和/或電容器配合使用。6.1IntroductionThefirstapplicationofanSVCtovoltagecontrolwasdemonstratedontheTri-StateG&TSystemin1977byGeneralElectricCo.(GE),whichisheadquarteredinFairfield,Conn.1977年，總部位于康涅狄格州費爾菲爾德的通用電氣公司（GE）在三州G&T系統(tǒng)上首次展示了SVC在電壓控制方面的應(yīng)用。6.1IntroductionAnotherSVCwithvoltageandstabilitycontrol,developedwithEPRIfundingbyWestinghouseElectricCorp.ofPittsburghbeganoperationin1978ontheMinnesotaPowerandLightSystem.(incidentally,sinceEPRI’slaunchingoftheflexibleactransmissionsystemstrategyin1986,themarketforSVCshasincreasedsubstantially.)在EPRI的資助下，由匹茲堡西屋電氣公司開發(fā)的另一款具有電壓和穩(wěn)定性控制功能的SVC于1978年開始在明尼蘇達電力和照明系統(tǒng)上運行（順便提一下，自EPRI于1986年推出靈活交流輸電系統(tǒng)戰(zhàn)略以來，SVC的市場大幅增長）。6.1IntroductionThesecondcontrollerinactualuseistheNGH-SSRDamper,invertedtocountersub-synchronousresonance(SSR).SSRinstabilitiesareattimesanundesirablesideeffectofusingamechanicallycontrolledseriescapacitortoaddupto80percentcompensationtoatransmissionline,thegoalbeingtolowertheline’simpedance,increasepowerflow,andexpandstabilitylimits.實際使用中的第二種控制器是NGH-SSR阻尼器，可反轉(zhuǎn)以對抗次同步諧振（SSR）。SSR不穩(wěn)定性有時是使用機械控制串聯(lián)電容器為輸電線路增加高達80%補償，其目的是降低線路阻抗、增加潮流和提高穩(wěn)定性極限。6.1IntroductionIntheearly1970s,aftertheshaftofaturbinegeneratorbelongingtoSouthernCaliforniaEdisonCo.wasdamagedbysub-synchronousresonance,theseriescompensationlevelonamajor500-kVtransmissioncorridorhadtobereduced,sothatlesspowercouldbetransferredoverit.20世紀(jì)70年代初，在南加州愛迪生公司的一臺渦輪發(fā)電機的軸因次同步諧振而損壞后，一條主要的500千伏輸電走廊上的串聯(lián)補償電壓不得不降低，從而減少了通過該走廊傳輸?shù)碾娏Α?.1IntroductionSincethen,varioussolutionstotheproblemsofsensingsub-synchronousresonance,emergency-switching,blockingit,andsoon,havebeenadopted.此后，針對亞同步諧振的感應(yīng)、緊急切換、阻斷等問題，人們采取了各種解決方案。6.1IntroductionTheNGH-SSRdamperconsistsofathyristoracswitch(back-to-backthyristors)connectedinserieswithasmallinductorandresistoracrosstheseriescapacitor.Theoperationofthedamperisbasedontwoprinciples.Oneistofiretheswitch8.33msaftereachzeroofthecapacitor’svoltage,orhalfacycle(or180degrees)at60Hz.NGH-SSR阻尼器由一個晶閘管交流開關(guān)（雙向晶閘管）串聯(lián)一個小電感電阻后再與一個串聯(lián)電容器并聯(lián)構(gòu)成。阻尼器的運行基于兩個原理。其一是在電容器電壓每次為零后8.33毫秒或60赫茲的半個周期（或180度）啟動開關(guān)。6.1IntroductionButifthevoltagewavecontainsotherfrequencies,somehalfcycleswillbelongerthan8.33ms.Inthiscasethevalvefiringat8.33mscausessomecurrenttoflowduringtheextendedpartofthehalfcycleanddampstheoscillations.Thesecondprincipleistofiretheswitchsomewhatearlierthan8.33ms,orlessthan180degreesfollowingthezero.但如果電壓波形包含其他頻率，則某些半周期將長于8.33毫秒。在這種情況下，閥門在8.33毫秒發(fā)射導(dǎo)致一些電流在半周期的延長部分流動，并抑制振蕩。第二個原則是啟動開關(guān)稍早于8.33毫秒，或小于零后180度。6.1IntroductionEarlierfiringcausestheimpedanceofthecombinedcircuittobemorenegativethanthatwiththecapacitoralone,thusdetuningtheelectriccircuit.Furthermore,bythemodulationofthefiringangle,theimpedancecanhaveapowerfuldampingeffectatanyunwantedfrequencybelowthemainfrequency.提前啟動會使組合電路的阻抗負值大于單獨使用電容器時的阻抗負值，從而使電路失諧。此外，通過調(diào)節(jié)啟動角度，阻抗可在主頻以下的任何不需要的頻率上產(chǎn)生強大的阻尼效應(yīng)。6.1IntroductionInanSSRdamperinstalledinSouthernCaliforniaEdison’sLugosubstation[Fig.6.2],thethyristorshaveamodestcurrentrating(15percentofload)forcontinuouslybypassingthecapacitor’swaveforonlyuptothelast10degreesorsoofthevoltagewave.Withmorecoolingofthethyristorsandappropriatesizingofthereactororresistorinserieswiththethyristorswitch,thisdamperformsthebasisforthefullyratedthyristor-controlledseriescapacitordescribedlater.在安裝在南加州愛迪生公司盧戈變電站的SSR阻尼器中[圖6.2]，晶閘管具有有限的額定電流(負載的15%)，可以連續(xù)通過電容器的波，直到電壓波的最后10度左右。隨著晶閘管的更多冷卻和與晶閘管開關(guān)串聯(lián)的電抗器或電阻器的適當(dāng)尺寸，該阻尼器形成了后面描述的定晶閘管控制串聯(lián)電容器的基礎(chǔ)。6.1IntroductionFig.6.2Resonancedamperanditsapplication圖6.2共振阻尼器及其應(yīng)用6.1IntroductionWiththerecognitionofflexibleactransmissiontechnologyasahighlyeffectivemeansofenhancingpowersystems,asecondgenerationofcontrollersisbegtoemerge.Aboutadozenthyristor-basedsystemshavebeenidentifiedaslikelytoimprovetheperformanceofanacsystem.SixarebeingpursuedfordevelopmentaspartofEPRI’sproposed10-yearcollaborativeR&Dplanforthetechnology.隨著人們認識到靈活的交流輸電技術(shù)是提高電力系統(tǒng)性能的有效手段，第二代控制器開始出現(xiàn)。目前已確定約有十幾種基于晶閘管的系統(tǒng)有可能提高交流系統(tǒng)的性能。作為EPRI提出的該技術(shù)10年合作研究與開發(fā)計劃的一部分，目前正在開發(fā)六種系統(tǒng)。6.1IntroductionObviously,Mostvitaltopowerandstabilitycontrolistheabilitytocontrolimpedanceorphaseangle.Sincetheseriesimpedanceofatypicaltransmissionlineismostlyinductive,withonly5-10percentresistive,itisconvenienttocontrolapowersystem'ssteady-stateimpedancebyaddingbothathyristor-controlledseriescapacitorandathyristor-controlledseriesreactor(inductor).顯然，對于功率和穩(wěn)定性控制而言，最重要的是控制阻抗或相角的能力。由于典型輸電線路的串聯(lián)阻抗大多為感性阻抗，只有5-10%是阻性的，因此可以很方便地通過增加晶閘管控制的串聯(lián)電容器和晶閘管控制的串聯(lián)電抗器來控制電力系統(tǒng)的穩(wěn)態(tài)阻抗。6.1IntroductionSincethecapacitorisanegativeimpedance,theintroductionofavariableseriescapacitormeansavariablenegativeimpedanceinserieswiththeline'snaturalpositiveimpedance.由于電容器是一個負阻抗，因此引入一個可變串聯(lián)電容器意味著在線路的自然正阻抗上串聯(lián)了一個可變負阻抗。6.1IntroductionThusthethyristor-controlledseriescapacitorcanvarytheimpedancecontinuouslytolevelsbelowanduptotheline'snaturalimpedance.Ontheotherhand,addingathyristor-controlledseriesreactormeansaddingavariablepositiveimpedancetoavalueabovetheline'snaturalpositiveimpedance.因此，晶閘管控制的串聯(lián)電容器可以連續(xù)改變阻抗，使其達到低于和高于線路自然阻抗的水平。另一方面，增加晶閘管控制的串聯(lián)電抗器意味著增加一個可變的正阻抗，其值高于線路的自然正阻抗。6.1IntroductionOnceinstalled,itwilleitherrespondrapidlytocontrolsignalstoincreaseordecreasethecapacitanceorinductance,therebydampingthosedominantoscillationfrequenciesthatwouldotherwisebreedinstabilitiesorunacceptabledynamicconditionsduringandafteradisturbance.安裝后，它將對控制信號做出快速反應(yīng)，增大或減小電容或電感，從而抑制那些主要的振蕩頻率，否則在擾動期間和擾動之后，這些頻率將導(dǎo)致不穩(wěn)定或不可接受的動態(tài)條件。6.1IntroductionThefirstofthenewcontrollerstobedemonstratedonautilitytransmissionsystemisthethyristor-controlledseriescapacitor(TCSC).In1991,AmericanElectricPowerCo.ofColumbus,Ohio,begantestingaprototypeswitchononephaseoftheseriescapacitorbankatits345-kVKanawhaRiverSubstationinWestVirginia.晶閘管控制串聯(lián)電容器(TCSC)是第一個在電網(wǎng)輸電系統(tǒng)上演示的新型控制器。1991年，俄亥俄州哥倫布市的美國電力公司開始在其位于西弗吉尼亞州的345千伏卡納瓦河變電站的串聯(lián)電容器組的一個相上測試原型開關(guān)。6.1IntroductionTheswitchwassuppliedbyAseaBrownBoveri,Vasteras,Sweden.Althoughtheswitchisnotstrictlyspeakingathyristorcontrolledseriescapacitorandthetestinstallationisonlysinglephase,therapidswitchingofcapacitorsegmentsinandoutofthecircuitdotestthekeyhardware.Insomeapplications,thethyristor-basedswitchingisjustifiableforitsreliabilityandspeed.開關(guān)由瑞典瓦斯塔斯的AseaBrownBoveri公司提供。雖然從嚴格意義上講，開關(guān)并不是晶閘管控制的串聯(lián)電容器，而且測試裝置也只是單相的，但電容器在電路中的快速開關(guān)確實對關(guān)鍵硬件進行了測試。在某些應(yīng)用中，基于晶閘管的開關(guān)因其可靠性和速度而具有合理性。6.1IntroductionInoctober1992,theWesternAreaPowerAdministration(WAPA),Golden,Colo.,dedicatedthefirstthree-phasethyristor-controlledseriescapacitorinstallation.ItwasbuiltbyMunich-basedSiemensAGandinstalledattheWAPAKayentaSubstationinArizonaina300-km,230-kV,300-MWtransmissionline.1992年10月，位于科羅拉多州戈爾登市的西部地區(qū)電力管理局（WAPA）投入使用了第一套三相晶閘管控制串聯(lián)電容器裝置。該裝置由總部位于慕尼黑的西門子公司制造，安裝在亞利桑那州WAPAKayenta變電站的一條300公里、230千伏、300兆瓦的輸電線路上。6.1IntroductionTheinstallationincludesthreesegments:one15-Ω,one40-Ω,andone55-Ωseriescapacitorbank.Onlythe15-Ω(45-MVA)bankisthyristorcontrolled.Thisinstallationisapioneeringstepbecausethe15Ωbankcanbecontrolledsmoothlyandrapidlyfrom15Ωto60ΩthroughthecontrolledfiringangleofthethyristorvalvesasintheNGHsub-synchronousresonancedamper,butoverawiderrange,from145degreesto180degrees.該裝置包括三個部分：一個15Ω、一個40Ω和一個55Ω的串聯(lián)電容器組。只有15Ω（45-MVA）的電容器組采用晶閘管控制。這一裝置具有開創(chuàng)性意義，因為與NGH亞同步諧振阻尼器一樣，通過可控晶閘管閥的觸發(fā)角，15Ω電容器組可以平穩(wěn)、快速地從15Ω控制到60Ω，但控制范圍更廣，從145度到180度不等。6.1IntroductionTheinstallationallowsthetransmissionlinecapacitytobeincreasedfrom300MWto400MW.安裝后，輸電線路的容量可從300兆瓦增至400兆瓦。6.1IntroductionTheconstructionofalargethree-phasethyristor-controlledseriescapacitorinstallationona500-kVlineisinprogressattheSlattSubstationofBonnevillePowerAdministration(BPA)inOregon.(ThisBPAlineisconnectedtoPortlandGeneralElectricCo.'sBoordmanpowerplantinOregon.)Theinstallationfeaturesafullrangeofcontrolsandoperatingrequirements.俄勒岡州邦納維爾電力管理局(BPA)的Slatt變電站正在一條500千伏線路上安裝大型三相晶閘管控制串聯(lián)電容器。(該