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600MW发电机组励磁变故障分析 Introduction: Excitationtransformerplaysanimportantroleintheoperationofapowerplant.Itisresponsibleforprovidingpowertotheexcitationsystemofagenerator.Thefailureofthistransformercanhaveseriousconsequences,includingshuttingdownthegeneratingunit,anditcanalsoleadtosignificantfinanciallossestothepowerplant.Inthispaper,wewillanalyzethefailureofa600MWexcitationtransformeranddiscussthepossiblecausesandsolutionsforthisproblem. FaultAnalysis: Thefaultintheexcitationtransformerwasinitiallydiscoveredbyasuddendropinthevoltagelevel.Thegeneratorvoltagewasfoundtobedroppingabnormally,belowthesetlevel,andcausingthegeneratorspeedtodecrease.Uponfurtherinvestigation,itwasrevealedthattheexcitationtransformerhadfailed. Thefirststepinanalyzingthisfaultwastochecktheexcitationtransformeranditsassociatedsystems.Theinitialvisualinspectionshowednoobviousdamageorsignsoffailure.However,furthertestingrevealedaninternalshortcircuitinthetransformer,whichcouldhaveresultedfromanynumberoffactors,suchasage,insulationdeterioration,orincorrectinstallation. Apartfromthis,itwasdiscoveredthattheautomaticvoltageregulator(AVR)hadalsomalfunctioned.ItwasfoundthattheAVRwasunabletoadjusttheexcitationvoltageandmaintaintherequiredlevel,resultinginfluctuationsinthevoltagelevelofthegenerator.ThiswasfoundtobeduetomalfunctioningofAVRcomponents,suchasthevoltageregulatorandthepowermodule. Solutions: Thefirstpriorityforsolvingthisissuewastorepairorreplacetheexcitationtransformer.Thetransformerwasdismantled,andtheinternalshortcircuitwaslocatedatthecoreofthetransformer.Thetransformerrequiredreplacement,andanewtransformerwassourcedandinstalled.Additionally,thebushingsofthetransformerandtheentiretransformeroilwerereplaced,andthetransformerwastestedbeforebeingputbackintooperation. ThenextstepwastoreplacethemalfunctioningAVRcomponents.Thevoltageregulatorandpowermodulewerereplacedwithnewcomponents,andtheAVRwasre-testedandcalibratedtoensureproperfunctionality. Anothersolutiontopreventfuturesimilarexcitationtransfor