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(bǔ)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(jī)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(xiǎn)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(diǎn)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(yùn)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(jìn)入一個(gè)變革時(shí)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(yùn)行達(dá)到了前所未有的精細(xì)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(gè)項(xiàng)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(shí)，可以進(jìn)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(jìn)行分類?，F(xiàn)有的靜止無功補(bǔ)償（SVC）或者可控串聯(lián)補(bǔ)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(bǔ)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(xiàng)包含在設(shè)備中，如風(fēng)力渦輪機(jī)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(jī)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(gè)提高效率的契機(jī):6.1Introduction①Greatercontrolofpower,sothatitflowsontheprescribedtransmissionroutes.②Secureloading(butnotoverloadingoftransmissionlinestolevelsnearertheirthermallimits.③Greaterabilitytotransferpowerbetweencontrolledareas,sothatthegenerationreservemargin-typically18percent-maybereducedto15percentorless.①更強(qiáng)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(fù)荷(但不能超載)，使其接近其熱穩(wěn)定極限。③更強(qiáng)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(jì)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(yán)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(yùn)行，500千伏線路的負(fù)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(jī)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(jī)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(bǔ)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(dú)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(jìn)一步發(fā)展。6.1IntroductionElectricpowernetworksintegrategenerationandloadcenterswithineachutilitysystemandsharepowerwithvastregionalgridsthroughinterconnectionsamongneighboringsystems.Thepurposeofthisistotakeadvantageofthediversityofloads,changesinpeakdemandduetoweatherandtimedifferences,theavailabilityofdifferentgenerationreservesinvariousgeographicregions,power-sharingarrangementsamongutilities,shiftsinfuelprices,regulatorychanges,andotherdiscrepancies.電力網(wǎng)絡(luò)將每個(gè)電力系統(tǒng)內(nèi)的發(fā)電和負(fù)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(fù)荷的多樣性、因天氣和時(shí)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(jià)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(jìn)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(kuò)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?yàn)樵絹碓蕉嗟淖杂冒l(fā)電機(jī)(UNGs)進(jìn)入市場，而且因?yàn)殡娏局g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(qiáng)調(diào)的是，對于大量的容量擴(kuò)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(jì)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(gè)眾所周知的公式表明，沿傳輸線兩點(diǎn)之間的功率流等于兩點(diǎn)電壓的乘積，乘以它們相角差的正弦值，再除以兩點(diǎn)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(gè)基本的情況，兩臺發(fā)電機(jī)通過一個(gè)由三條線組成的網(wǎng)格連接網(wǎng)絡(luò)向負(fù)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(jī)的額定功率為2000MW，另一臺發(fā)電機(jī)的額定功率為1000MW，則總共將向負(fù)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(fù)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(gè)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(shí)現(xiàn)其他功率流水平。這種電容器可以采用模塊化和機(jī)械切換的方式。但機(jī)械部件上的氣動觸頭會嚴(yán)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(jī)軸的機(jī)械諧振頻率等于電網(wǎng)的60Hz減去串聯(lián)補(bǔ)償產(chǎn)生的電磁諧振頻率時(shí)，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(yùn)行并承載更高的負(fù)載時(shí)，低頻(通常為1-2Hz)的潮流振蕩可能會導(dǎo)致發(fā)電機(jī)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(yùn)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(jìn)入另一種穩(wěn)定狀態(tài)，而不會損壞發(fā)電機(jī)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(shí)際的做法往往是部分串聯(lián)補(bǔ)償由機(jī)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(jī)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(gè)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(dá)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(jī)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(jìn)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(gè)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(bǔ)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(jī)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(fèi)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(dá)電力和照明系統(tǒng)上運(yùn)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(shí)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(shí)是使用機(jī)械控制串聯(lián)電容器為輸電線路增加高達(dá)80%補(bǔ)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(jī)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(bǔ)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(gè)晶閘管交流開關(guān)（雙向晶閘管）串聯(lián)一個(gè)小電感電阻后再與一個(gè)串聯(lián)電容器并聯(lián)構(gòu)成。阻尼器的運(yùn)行基于兩個(gè)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(gè)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(gè)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(fù)值大于單獨(dú)使用電容器時(shí)的阻抗負(fù)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(qiáng)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(fù)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(rèn)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(jì)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(gè)負(fù)阻抗，因此引入一個(gè)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(gè)可變負(fù)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(dá)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(gè)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(gè)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(gè)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(yán)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(shí)對關(guān)鍵硬件進(jìn)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?duì)柕鞘械奈鞑康貐^(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(gè)部分：一個(gè)15Ω、一個(gè)40Ω和一個(gè)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?yàn)榕cNGH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