电力系统谐波成因分析及谐波潮流计算外文翻译.doc

电力系统谐波成因分析及谐波潮流计算外文翻译.doc

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Analysisofpowersystemovertoneandovertonetidalcurrenttocalculate

First,introductionanidealelectricalpowersystemisbythesoleconstantfrequencyandthestipulationpeak-to-peakvalueregulatedvoltagepowersupply.Butinfact,asaresultoftherecentyearsalongwithscience'sandtechnology'sunceasingdevelopment,thehighefficiencytradedtheclassequipmentandthemodulatoruse,highintheelectricalpowersystempressesthenonlinearelementwhichthedirectcurrenttransmissiontheapplication,themassivemisalignmentload'sappearanceaswellasthepowersupplysystemitselfexistedandsoontocauseinthesystem'svoltagewaveformdistortiontobegettingmoreandmoreserious,hascausedtheverybigharmtotheelectricalpowersystem,forexample:

Causesinthepowersupplysystemtheparttoloseincreases,reducescurrentcollector'sservicelife,todisturbthecommunicationsystemandsoon.Seriouswhenevencanalsocauseequipmentthedamage,automaticcontrolmalfunction,relayprotectionmisoperation,thuscreatesthepowercutaccidentandsoonandotherquestions.So-called"thefriendknowsother,isundefeatedinmanybattles",therefore,mustrealizetotheelectricalnetworkovertonecomprehensiveprogramofpublicorder,mustmakecleartheovertoneoriginandtheelectricalnetworkinundertheeachdifferentmovementwaytheovertonetidalcurrentdistributedsituation,adoptsthecorrespondingmeasurelimitandtheharmoniccancellation,thuschangesthefriendlypowersupplysystempowersupplyqualityandguaranteessystem'ssecurityeconomymovement.

Second,electricalpowersystemovertone'soriginintheelectricalpowersystemtheovertonesourceismanyandvaried.Mainlyhasthefollowingseveralkinds:

in1,system'seachkindofmisalignmentcurrentcollectorforexample:

Tradestheclassequipment,themodulator,theelectrificationrailroad,thearcfurnace,fluorescencethelamp,thedomesticelectricappliancesaswellaseachkindofelectronicenergyconservationcontroldeviceandsoonistheelectricalpowersystemovertoneimportantsource.Eveniftheseequipmentsuppliesitsidealsinewavevoltage,itusestheelectriccurrentisalsonon-linear,namelyhastheharmoniccurrentexistence.Andthesetheequipmentproducestheharmoniccurrentwillalsopourintotheelectricalpowersystem,willcausesystemeachplacevoltagetohavetheharmoniccomponent.Theseequipment'sharmonythewavecontentdecidedthatinitscharacteristicandtheworkingcondition,basicallyhasnothingtodowiththeelectricalpowersystemparameter,mayregardasovertoneconstantflowthesource.2,thepowersupplysystemitselfexiststhenonlinearelementisovertoneanotherorigin.Thesenonlinearelementmainlyhasthetransformertostirupthecapacitorwhich,thereactorgroupthemagnetismleg,thealternatinganddirectconvertorstation'ssilicon-controlledrectifiercontrollingelement,thesilicon-controlledrectifiercontrolandsoon.

3rd,likethefluorescentlamp,thedomesticelectricappliancesandsoonsinglecapacityisnotbig,butquantityandspreadsverygreatlyineachplace,electricpowerdepartmentwithdifficultymanagementcurrentcollector.Iftheseequipment'scurrentharmonicscontentisoversized,willthenhavetheseriousinfluencetotheelectricalpowersystem,tothiskindofequipment'scurrentharmonicscontent,whenmanufacturenamelyshouldlimitincertainquantityscope.4,thegeneratorsendoutovertoneelectricpotential.Thegeneratorwillsendouttheovertoneelectricpotentialatthesametimealsotohavetheovertoneelectricpotentialproduction,itsovertoneelectricitythepotentialwillbedecidedbygenerator'sstructureandtheworkingcondition,basicallywillhavenothingtodowiththeexternalconnectionimpedance.Thereforemayregardasovertoneconstantpressuresource,butitsvalueisverysmall.

thethree,electricalpowersystemovertonetidalcurrentcalculatestheso-calledelectricalpowersystemovertonetidalcurrentcomputation,isthroughsolutionnetworkequationIn=YnUn（n=3,5,7......n:

Agreeswavenumberthenumber.Inistheovertonesourceloadpoursintoelectricalnetwork'snsubharmonicelectriccurrentrowvector.Yniselectricalnetwork'snsubharmonicconductance.Unisintheelectricalnetworkavariousnodesbusbarnsubharmonicvoltagerowvector）.Obtainsintheelectricalnetworkvariousnodes（busbar）theharmonicvoltage,enterstoobtaininvariouslegs'harmoniccurrent.

Whenintheelectricalpowersystemtheexistencehastheovertonesource,thistimeinthesystemthecontactvoltageandthebranchcurrentwillhavethehigherharmonic.Forthedeterminationharmonicvoltageandharmoniccurrent'sinpowersupplysystemdistribution,neededtocarryontotheovertoneimpedanceconstitutionequivalentcircuitthetidalcurrent