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附錄1:外文資料翻譯
A1.1SubstationandPowerSystemProtection
Withthedevelopmentofundertakngoftheelectricwirenetting,thepatternofnationalnetworkhasalreadytakenshape
basically.Scientificandtechnologicallevelraise,electricenvironmentalprotectioncanstrengthen,makescientificand
technologicalcompeienceandadvancedinternationalstandards,Chineseofpowerindustryclosedaybyday.Electric
managementlevelandservicelevelare?eingimprovedconstantly,strategicpanningmanagementofelectricpowerdevelopment,
productionoperatemanage,electricmarketadministrationandelectricinformationmanagementlevel,high-qualityservice
level,ctc.generaltoruiscenterprise.
Thepurposeofasubstationistotransformthecharacteristicsoftheelectricalenergysuppliedtosomeformsuitableforuse.
asforexample,aconversionfromalternationcurrenttodirectcurrentfortheuseofcityrailwayservice,orachangefromone
voltagetoanother,oronefrequencytoanother.Theirfunctionsinclude:
Tap.—TObeeconomical,transmissionoflargeramountsofpoweroverlongdistancesmustbedoneatvoltagesabove
1IO.(XX)volts.Substationsfbrsupplyingsmallamountsofpowerfromsuchhigh-voltagelinesarenotsatisfactoryfromthe
standpointofoperationandarealsouneconomical.Itis.therefore,commonpracticetoinstallafewsubstationsatadvantageous
pointsalongihehigh-lensionlinesandstepdownthehigh-lransmissionvoltage(oalowersecondary-transmissionvoltagefrom
wnichnumeroussmallloadsmaybesupplied.
Disiribulion.—Anysubstationthatisusedtotransformelectricalenergyioapoieniialthatislowenoughforgeneral
distributionandutilizationisadistributingsubstation.Suchasubstationwillgenerallyreceiveitsenergyoverafew
comparativelyhigh-tensionlinesanddistributeitoveralargenumberoflow-voltagelines.
Industrial.—Whenfairlylargeblodcsofpowerarerequiredbyindustrialplants,itoftenbecomesnecessaryandadvisableto
installanindividualsubstationtosupplysuchaloaddirectlyfromthemainhigh-voltagelineorsecondar}'lineoflowervoltage.
Itssimplestformwouldcompriseonlyswitchingequipment,therebeingnovoltagetransformation.Inmostcasesavoltage
transformationisprobablyneeded:hencetransformerequipmentisincluded.
Sectionalizing.——Inverylonghigh-voltagelargecapacitylines,particularlywhenseveralcircuitsareruninparallel.i(is
oftennecessarytosplitthelinesintosections,inorderthatproperprotectiontothelineandservicecanbeobtained.Sucha
substationis,therefore,helpfulinsectionalizingdamagedsectionsofaline,providingcontinuityofservice.Suchasubstation
willgenerallycompriseonlyswitchingequipment.Inlonglinesitmayalsoservetosupplypower-factor-correctingequipment.
Transmission-lineSupply.—Ilisbecomingmoreandmorecommontoinstallthehigh-tensionequipmentofapowerplant
outdoors,theinstallationbecomingnothingmore(hanastep-upsubstationreceivingitspoweratgeneratorvoltage,thenstepping
upitsvoltageandfinallysendingitoutoverhigh-voltagetransmissionlines.Suchasubstationisnothingmorethananoutdoor
distributingsubstationturnedaround,thevoltagebeingsteppedupinsteadofsteppeddown.
Power-factorCorrection.—Thevoltageattheendoflonglinestendstoincreaseastheloadsuppliedisdecreased,whileon
theotherhandittendstodecreaseastheloadisincreased.Owingtotheinductanceandcapacityeffects,thisvariat.oninvoltage
isaccompaniedbyawidevariationinpowerfactorofaline,itisnecessarytousesynchronouscondensersattheendoftheline.
Tosupplysuchamachinethetransmission-linevoltagemustbesteppeddown,henceapower-factor-correctingsubstationwill
includeswitchingequipment,transfonners.andallequipmentnecessaryfortheoperationofsynchronouscondensers.
Railway.—Substationssupplyingrailwaysmaybegenerallyclassifiedundertwoheads,namely,asalternatingcurrentandas
directcurrent.Inihecasesofalternating-currentsubslationstheproblemisgenerallyoneofvoltagetransformationandof
supplyingsingle-phasepowertothetrains.Itis.however,possibletosupplysingle-phasetothree-phaseinsidethebcomotiveby
theuseofaphaseconverter.Inthecaseofdirect-currentrailways,thesubstationsaregenerallysuppliedwhitthree-phasepower
ardconvertedtodirectcuiTentbymeansofrotaryconverters,motor-generatorsets,orrectifiers.
DirectcurrentforLightandPower.—Therearcstillafewsectionsinsomeofoutlargecities,whicharcsuppliedwith
direct-currentthree-wiresystems.Suchasupplyisinvariablyobtainedfromsynchronousconverters.Therearealsocertaintypes
ofmotorloadsinindustrialplants,whichrequiredirectcurrent.
Becausemanycitieshaveexperiencerapidgrowth,theirsubstationshaveoftenreachedthelimitsoftheircapacity.Asa
result,downtowndistributionsystemsareoftenoverworkedandmanyneedamajor,overhaul,overhaul,orexpansion.However,
spaceisscarce.Downtownbusinessownersdonotwant"ugly"newsubstationmarringthearea'sappearance,butnordo
businessesandresidentsgridtheprospectofgriddisturbances.
OneexampleofasystemcapableofintegratingequipmentmonitoringwithsubstationautomationistheGEHarris
integratedSubstationControlSystem(ISCS).Thesystemcanintegratedatafrombothsubstationsystemandequipmentonline
monitoringdevicesintoacomniondatabase.Thedatacanthenbeprocessedbyanexpertsystemintoinformationonthestatus
ardhealthofmonitoredequipmentusingself-diagnosticprograms.ThisinformationisthensenttoaCMMSfbrautomatic
generationandtrackingofmaintenanceworkordersleadsdirectlytothesignificantefficienciesfoundwithcondition-based
muintcnunccprograms.
ABBPoweranditsindustrypartnershavecombinedtodeveloptheABBPowerSystemsoftware.Thesystemcontainsa
diagnosticandmaintenancesystemthatreportsnecessarymaintenancebeforefailure.Itallowsutilitiesandindustrialcustomers
toeasilyexpandfromasinglecomputertoafullsystem,withoutre-engineering.
thedirectionalprotectionbasis
Earlyallemptstoimprovepower-servicereliabilitytoloadsremotefromgenerationledtothedual-lineconcept.Ofcourse,it
ispossibletobuildtwolinestoaload,andswitchtheloadtowhicheverlineremainsenergizedafteradisturbance.Butbetter
servicecontinuitywillbeavailableifbothlinesnormallyIcedtheloadandonlythefaultedlineistrippedwhendisturbances
occur.Fig.14-1showsasingle-generatcr.two-line,single-loadsystemwithbreakersproperlyanangedtosupplytheloadwhen
onelineisfaulicd.Forihearrangememiobeeffeciivei【isnecessaryiohaveiheproperrelayapplicaiion.Oiheruuse,ihc
expensivepowerequipmentwillnotbeabletoperformasplanned.Considertheapplicationofinstantaneousand/ortimedelay
relaysonthefourbreakers.Obviouslyihetypeoftherelaycannotcoordinateforalllinefaults.Forexample,afaultontheline
terminalsofbreakerD.DtrippingshouldbefasterthanB.however,theconditionreversesandBshouldbefasterthanD.Itis
evidentthattherelayprotectionengineermustfindsomecharacteristicotherthantimedelayifrelaycoordinationistobe
achieved.
ThemagnitudeofthefaultcurrentthroughbreakersBandDisthesame,regardlessofthelocationofthefaultontheline
terminalofbreakerBorD.Thereforerelaycoordinationmusthebasedoncharacteristicsotherthanatimedelaythatstartsfrom
thetimeofthefault.ObservethatthedirectionofcunentflowingthrougheitherbreakerBorDisafunctionofwhichlinethe
faultison.ThusforafaultonthelinebetweenAandB,thecurrentflowsoutoftheloadbusthroughbreakerBtov/ardthefault.
A;breakerDthecurrentflowstowardtheloadbusthroughbreakerD.InthiscasebreakerBshouldtrip,butbreakerDshouldnot
trip.ThiscanbeaccomplishedbyinstallingdirectionalrelaysonbreakersBandDthatareconnectedinsuchawaythattheywill
triponlywhencurrentflowsthroughtheminadirectionawayfromtheloadbus.
RelaycoordinationforthesystemshowninFig.14-1cannowbeachievedbytheir-salvationsofdirectiona.overcurrent
timedelayrelaysonbreakersBandD.BreakersAandCcanhavenodircctionalovcrcurrenttimedelayrelays.Theymayalso
nowhaveinstantaneousrelaysapplied.Therelayswouldbesetasfollows:Tl:edirectionalrelayscouldbesetwithnointentional
timedelay.Theywillhaveinherenttimedelay.ThetimedelayovercurrentrelaysonbreakersAandCwouldhavecurrentsettings
thatwouldpermitthemtosupplybackupprotectionforfaultsontheloadbusandforloadequipmentfaults.Theinstantaneous
elementsonbreakersAandCwouldhavecurrentsettingsthatwouldnotpermitthemtodetectfaultsontheloadbus.Thusthe
linesbetween(hegeneratorandtheloadwouldhavehigh-speedprotectionoveraconsiderableportionof(heirlength.Itshouldbe
observedthatfaultsonthelineterminalsofbreakersAandCcancollapsethegeneratorvoltage.Theinstantaneousrelayson
breakersAandCcannotclearthecircuitinstantaneously,becauseitlakestimeforpowerequipmenttooperate.Duringthisperiod
therewillbelittleornocurrentflowthroughbreakersBandD.Tlierefbre.BorDcannotoperateforthisfaultconditionuntilthe
appropriatebreakerat(hegeneratingstationhasoperated.Thisisknownassequentialtripping.Usually,i(isacceptableunder
suchconditions.
Directionofcurrentflowonana.c.systemisdeterminedbycomparing:hecurrentvectorwithsomeotherreferencevector,
suchasavoltagevector.InthesystemofFig.14-1thereferencevoltagevectorwouldbederivedfromthevoltagesontheload
bus.Directionofcurrentorpowerflowcannotbedeterminedinstantaneouslyona.c.systemswhoselinesandequipmentcontain
reactance.Thisisapparentfromthetaelthatwhenvoltageexists,thelaggingcurrentcanhephisorminusorzero,dependingon
theinstantsampledinthevoltagecycle.Accordingly,thevectorquantitiesmustbesampledoveratimeperiod.Thetimeperiod
forreasonablyaccuratesamplingmaybefromone-halftoonecycle.Workisproceedingonshortersamplingperiodswhere
predictingcircuitsareaddedtotherelaytoattempttoestablishwhatthevectorswillbeatsomefuturetime.Theprocessis
complex,becauseitmustmakepredictionsduringthelimewhenelectricaltransientsexistonihcsystem.Usually,lieshorterthe
timeallowedfbrdeterminingdirection,(helessreliablewillbethedetermination.
differentialprotection
Muchoftheapparatususedonapowersystemhassmallphysicaldimensionswhencomparedtothelengthofgeneral
transmission-linecircuits.Therefore,thecommunicationsbetweentheapparatusterminalsmaybemadeveryecor.omicallyand
veryrcliublybytheuseofdirectwirecircuitconncclions.Thispennitsihcupplicutionofusimpleundusuallyverycffcclivctype
ofdifferentialprotection.Inconcept,(hecunententeringtheapparatusissimplycomparedagainstthecurrentleavingthe
apparatus.Ifthereisdifferencebetweenthetwocurrents,theapparatusistripped.Ifthereisnodifferenceinthecurrents,the
apparatusisnormalandnotrippingoccurs.Suchschemescanusuallybemaderathersensitivetointernalfaultsandvery
insensitivetoexternalfaults.Therefore,relaycoordinationisinherentinthedifferentialrelayscheme.
ThesimplestapplicationofdiflerentialrelayingisshowninFig.14-4.Hereonesimplepowerconductorisprotectedbya
differentialrelay.Therelayitselfusuallyconsistsofthreecoils,oneofwhichisthecoilthatdetectsthedifferencecurrentand
initiatescircuittripping.ItiscalledihcoperatingcoilandisdesignatedbyanOinthefigure.TheotherIwocoilsarerestraint
coilsandaredesignatedbyRinthefigure.Therestraintcoilsserveapracticalpurpose.Theypreventoperationforsmall
differencesinthetwocurrentiransfonncrsihaicanneverbeexactlyidentical,asaresultofinanutaciuringandotherdifferences.
O:herwise.therestraintcoilsservenotheoreticalpurpose.Fig.14-4showstheconditionofcurrentflowforanexternalfault
duringwhichtherelayshouldnottrip.ThecurrentIIenterandleavesthepowercircuitwithoutchange.Thecurrenttransformers
areassumedtohaveaI:Iratioforsimplicity,andtheirsecondarywindingsareconnectedtocirculatetheIIcurren:sthroughthe
restraintcoilsofthedifferentialrelayonly.Ifcurrentleftorenteredthepowercircuitbetweenthetwocurrenttransformers(an
internalfault),thenthecurrentsinthetransformerswouldbedifierent,andthedifferencecurrentwouldflowthroughthe
operatingcoiloftherelay.
本文
譯自《電力英語(yǔ)閱讀》
A1.2變電站與電力系統(tǒng)繼電保護(hù)
隨著電力電網(wǎng)事業(yè)的開(kāi)展,全國(guó)聯(lián)網(wǎng)的格局已根本形成??萍妓降玫教岣?,電力環(huán)境保護(hù)得以加強(qiáng),使中國(guó)電力
工業(yè)的科技水平與世界先進(jìn)水平日漸接近。電力管理水平和效勞水平不斷得到提高,電力開(kāi)展的戰(zhàn)略規(guī)劃管理、生產(chǎn)運(yùn)
行管理、電力市場(chǎng)營(yíng)銷(xiāo)笥理以及電力企業(yè)信息管理水平、優(yōu)質(zhì)效勞水平等普遍得到提高。
變電站的目的是改變電能特性以滿(mǎn)足使用要求。例如,從交流轉(zhuǎn)換為直流為城市鐵路供電,或者從一個(gè)電壓等級(jí)轉(zhuǎn)換
為另一十電s等級(jí).或者從一個(gè)頻率廢換為另?個(gè)頻率.變電站的功能包括:
分支一一為了經(jīng)濟(jì)性,大容量電力的遠(yuǎn)距離傳輸必須在llOkV以上的電壓下進(jìn)行。從運(yùn)行的角度來(lái)看,從這樣的高壓
線(xiàn)直接引出向小容量負(fù)荷供電的變電站是不能令人滿(mǎn)意的,也是不經(jīng)濟(jì)的。因此,一個(gè)常規(guī)方法是:沿著高壓線(xiàn)路在適
令的地點(diǎn)設(shè)置一些變電站,將高傳輸電壓降到一個(gè)較低的二級(jí)傳輸電壓,從這個(gè)電壓向小容量負(fù)荷供電。
配電一一任何用于將電能變換為可以直接配電和利用的較低壓等級(jí)的電能的變電站都是配電變電站。這樣的變電站一
股將從A條電壓相對(duì)高的線(xiàn)路接受電能,并向大量較低電壓線(xiàn)路配送電能。
工業(yè)一一當(dāng)工廠需要大量電能時(shí),設(shè)置一個(gè)自己的單獨(dú)的變電站是有必要的也是明智的,這個(gè)變電站直接從主高壓線(xiàn)
路或較低電壓的:級(jí)輸電線(xiàn)路取得電能。其最簡(jiǎn)單的形式?jīng)]有電壓的轉(zhuǎn)換,只由開(kāi)關(guān)設(shè)備組成。但是,在大多數(shù)情況下
需要一個(gè)電壓轉(zhuǎn)換,因此工業(yè)變電站應(yīng)該包括變壓器設(shè)備。
分段一一在很多高壓大容量的長(zhǎng)線(xiàn)路中,尤其是幾條線(xiàn)路并聯(lián)運(yùn)行時(shí),經(jīng)常需要用線(xiàn)跖分段,目的是為了使線(xiàn)路獲得
適當(dāng)?shù)谋Wo(hù)和維護(hù)。這樣的變電站有助于隔寓線(xiàn)路中的故障段,保證連續(xù)供電。這種變電站通常只由開(kāi)關(guān)設(shè)備組成。在
長(zhǎng)線(xiàn)路中,還可以提供功率因數(shù)調(diào)整設(shè)備。
輸電線(xiàn)路的電源一一在發(fā)電廠的戶(hù)外設(shè)置高壓設(shè)備已經(jīng)變得越來(lái)越昔遍,安裝的裝置只不過(guò)是?個(gè)升壓電站,它以發(fā)
電機(jī)電壓接受電能,然后將電壓升高,并最終通過(guò)高壓輸電線(xiàn)路將電能送出。這種變電站只不過(guò)是將戶(hù)外配電變電站反
過(guò)來(lái),電壓是被升高而不是降低。
功率因數(shù)調(diào)整一一隨著供電負(fù)荷的減小,長(zhǎng)線(xiàn)路末端的電壓趨向于升高,而隨著供電負(fù)荷的增大,線(xiàn)路末端的電壓
趨向于降低。由于電感和電容的影響,這個(gè)電壓的變化將伴隨著線(xiàn)路功率因數(shù)而變化,因此有必要在線(xiàn)路末端設(shè)置同步
調(diào)相機(jī)。為了向同步調(diào)相機(jī)供電,就必須將高壓輸電線(xiàn)路的電壓降低,因此,一個(gè)功率因數(shù)調(diào)整變電站將包括開(kāi)關(guān)設(shè)備、
變壓器和所付運(yùn)行同步訓(xùn)相機(jī)所需要為設(shè)備。
鐵路------般地,向鐵路供電的變電站分為兩類(lèi),即交流類(lèi)和直流類(lèi)。如果是交流變電站,其問(wèn)題一般是一個(gè)電壓轉(zhuǎn)
換和向鐵路機(jī)車(chē)負(fù)荷單相供電的問(wèn)題。然而,也有可能在機(jī)車(chē)內(nèi)通過(guò)相位變換錨由單相電源向三相負(fù)荷供電。如果是直
流鐵路,這種變電站一般由三相電源供電,并通過(guò)旋轉(zhuǎn)變流器、電動(dòng)機(jī)——發(fā)電機(jī)組或者整流器等將交流變換為直流。
照明和動(dòng)力用直流一一現(xiàn)在,仍然有一些在大城市.以外的地區(qū)采用直流三線(xiàn)系統(tǒng)供電,這種電源總是從同步換流器
獲得。另外,工廠中還有某些類(lèi)型的電動(dòng)機(jī)負(fù)荷要求采用直流電源,這些一般都是由旋轉(zhuǎn)換流器供電。對(duì)?于電解工業(yè),
低壓直流電源絕對(duì)是必須的,因此也需要使用電動(dòng)機(jī)一一發(fā)電機(jī)組或旋轉(zhuǎn)變記器。
由于城市不斷開(kāi)展,許多城市變電站已經(jīng)到達(dá)其負(fù)荷極限,所以市區(qū)配電系統(tǒng)經(jīng)常是超負(fù)荷運(yùn)行,許多配電站急需
升級(jí)、檢修或擴(kuò)建,問(wèn)題是空間缺乏。市中心的業(yè)主不希望外觀“丑陋■'的新變電站影響當(dāng)?shù)氐耐糜^,商家和居民也不
恁將來(lái)被星羅棋布的電網(wǎng)所干擾。
變電站自動(dòng)化的新趨勢(shì)是狀態(tài)維修。ABB公司與聯(lián)邦?lèi)?ài)迪生公司合作開(kāi)發(fā)了?套貫穿整個(gè)系統(tǒng)的規(guī)劃,一旦聯(lián)邦?lèi)?ài)迪
生公司的配電系統(tǒng)發(fā)生故障,可使電能流向發(fā)生改變。聯(lián)邦?lèi)?ài)迪生公司的工程總裁邁克?羅維說(shuō):”對(duì)這幾個(gè)變電站的發(fā)
行包括肥現(xiàn)有的輻射狀的饋電系統(tǒng)改成環(huán)形母線(xiàn)系統(tǒng),以增加系統(tǒng)的穩(wěn)定性。"
GE哈里其變電站綜合控制系統(tǒng)(ISCS)就是一個(gè)將設(shè)備監(jiān)測(cè)與變電站自動(dòng)化相結(jié)合的系統(tǒng)。該項(xiàng)系統(tǒng)能夠?qū)?lái)自變
電站系統(tǒng)和設(shè)備在線(xiàn)監(jiān)控裝置的數(shù)據(jù)進(jìn)行綜合,并輸入數(shù)據(jù)庫(kù),然后由一個(gè)專(zhuān)家系統(tǒng)利用自我診斷程序進(jìn)行分析,得出
有關(guān)被監(jiān)測(cè)設(shè)備的運(yùn)行善的信息。該信息被發(fā)送到電腦維修管理系統(tǒng),自動(dòng)發(fā)出并傳送維修工作指令。由于維修指令的
發(fā)送得到了改善,極大地提高了基于狀態(tài)進(jìn)行維修程序的效率。ABB電力公司及其企業(yè)合作伙伴聯(lián)合開(kāi)發(fā)了ABB電力
系統(tǒng)軟件。該系統(tǒng)包括?套診斷維修系統(tǒng),能夠在出現(xiàn)故障前提交必要的維修報(bào)告。有「這一套系統(tǒng),電力公司和用電
單位不須經(jīng)過(guò)重新改造,只需一臺(tái)電腦,就能輕而易舉地?fù)碛幸惶淄暾南到y(tǒng)。
方向保護(hù)根底
早期,對(duì)于遠(yuǎn)離發(fā)電站的用戶(hù),為改善其供電的可竟性提出了雙回線(xiàn)供電的設(shè)想。當(dāng)然。也可以架設(shè)不同的兩回線(xiàn)
給用戶(hù)供電。在系統(tǒng)發(fā)生故障后,把用戶(hù)切換至任一條正常的線(xiàn)路。但更好的連續(xù)供電方式是正常以?xún)苫鼐€(xiàn)同時(shí)供電。
當(dāng)發(fā)生故障時(shí),只斷開(kāi)故障線(xiàn)。(圖:4-1]所示為?個(gè)單電源、單負(fù)載、雙回輸電線(xiàn)系統(tǒng)。對(duì)該系統(tǒng)配置適宜的斷路牌
后,當(dāng)一回線(xiàn)發(fā)生故障時(shí),仍可對(duì)負(fù)載供電。為使這種供電方式更為有效,還需配置適宜的繼電保護(hù)系統(tǒng),否那么,昂
貴的電力設(shè)備不能發(fā)揮其預(yù)期的作用??梢钥紤]在四個(gè)斷路器上裝設(shè)瞬時(shí)和延時(shí)起動(dòng)繼電器。顯然,這種類(lèi)型的繼電器
無(wú)法對(duì)所有線(xiàn)路故障進(jìn)行協(xié)調(diào)配合。列如,故障點(diǎn)在靠近斷路器D的線(xiàn)路端,D跳閘應(yīng)比B快,反之,B應(yīng)比D快。顯
然,如果要想使繼電器配合協(xié)調(diào),繼包保護(hù)工程師必須尋求除了延時(shí)以外的其他途徑。
無(wú)論故障點(diǎn)靠近斷路器B或D的哪一端,流過(guò)斷路靜B和D的故障電流大小是相同的。因此繼電保護(hù)的配合必須
以此為根底.而不是放在從故障開(kāi)始大動(dòng)的延時(shí)I,我們觀察通過(guò)斷路器R或D的電流方向是隨故障點(diǎn)發(fā)生在哪一-條線(xiàn)
躥上變化的。對(duì)于A和B之間的線(xiàn)路上的故障,通過(guò)斷路器B的電流方向?yàn)閺呢?fù)荷母線(xiàn)向故障點(diǎn)。對(duì)于斷路器D,電流
通過(guò)斷路器流向負(fù)載母線(xiàn)。在這種情況下,斷路器B應(yīng)跳閘,D不應(yīng)該跳閘。要到達(dá)這個(gè)目的,我們可以在斷路器B和
D上裝設(shè)方向繼電器,該方向繼電器的聯(lián)接應(yīng)該保證只有當(dāng)通過(guò)它們的電流方向?yàn)殡x開(kāi)負(fù)載母線(xiàn)時(shí)才起動(dòng)。
對(duì)于圖14-1所示的系統(tǒng),在斷路器B和D裝設(shè)了方向過(guò)流延時(shí)繼電器后,繼電器的配合才能實(shí)現(xiàn)。斷路器A和C
裝設(shè)無(wú)方向的過(guò)流延時(shí)繼電器及瞬時(shí)動(dòng)作的電流繼電器。各個(gè)繼電器整定配合如下:方向繼電器不能設(shè)置延時(shí),他們只
有本身固有的動(dòng)作時(shí)間。A和C
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