电气工程毕业设计外文资料翻译Word格式文档下载.docx

电气工程毕业设计外文资料翻译Word格式文档下载.docx

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外文资料原文：

AVirtualEnvironmentforProtectiveRelayingEvaluationandTesting

A.P.SakisMeliopoulosandGeorgeJ.Cokkinides

Abstract—Protectiverelayingisafundamentaldisciplineofpowersystemengineering.AtGeorgiaTech,weofferthreecoursesthatcoverprotectiverelaying:

anundergraduatecoursethatdevotesone-thirdofthesemesteronrelaying,agraduatecourseentitled“PowerSystemProtection,”andathree-and-a-half-dayshortcourseforpracticingengineers.Tomaximizestudentunderstandingandtrainingontheconcepts,theory,andtechnologyassociatedwithprotectiverelaying,wehavedevelopedanumberofeducationaltools,allwrappedinavirtualenvironment.Thevirtualenvironmentincludesa）apowersystemsimulator,b）asimulatorofinstrumentationforprotectiverelayingwithvisualizationandanimationmodules,c）specificprotectiverelaymodelswithvisualizationandanimationmodules,andd）interfacestohardwaresothattestingofactualrelayingequipmentcanbeperformed.Werefertothissetofsoftwareasthe“virtualpowersystem.”Thevirtualpowersystempermitsthein-depthcoverageoftheprotectiverelayingconceptsinminimumtimeandmaximizesstudentunderstanding.Thetoolisnotusedinapassiveway.Indeed,thestudentsactivelyparticipatewithwell-designedprojectssuchasa）designandimplementationofmultifunctionalrelays,b）relaytestingforspecificdisturbances,etc.Thepaperdescribesthevirtualpowersystemorganizationand“engines,”suchassolver,visualization,andanimationofprotectiverelays,etc.Italsodiscussestheutilizationofthistoolinthecoursesviaspecificapplicationexamplesandstudentassignments.

IndexTerms—Algebraiccompanionform,animation,relaying,time-domainsimulation,visualization.

I.INTRODUCTION

RELAYINGhasalwaysplayedaveryimportantroleinthesecurityandreliabilityofelectricpowersystems.Asthetechnologyadvances,relayinghasbecomemoresophisticatedwithmanydifferentoptionsforimprovedprotectionofthesystem.Itisindisputablethatrelayinghasmadesignificantadvanceswithdramaticbeneficialeffectsonthesafetyofsystemsandprotectionofequipment.Yet,becauseofthecomplexityofthesystemandmultiplicityofcompetingfactors,relayingisachallengingdiscipline.

Despitealloftheadvancesinthefield,unintendedrelayoperations（misoperations）dooccur.Manyeventsofoutagesandblackoutscanbeattributedtoinappropriaterelayingsettings,unanticipatedsystemconditions,andinappropriateselectionofinstrumenttransformers.Designofrelayingschemesstrivestoanticipateallpossibleconditionsforthepurposeofavoidingundesirableoperations.Practicingrelayengineersutilizeatwo-stepproceduretominimizethepossibilityofsuchevents.First,inthedesignphase,comprehensiveanalysesareutilizedtodeterminethebestrelayingschemesandsettings.Second,ifsuchaneventoccurs,anexhaustivepost-mortemanalysisisperformedtorevealtherootcauseoftheeventandwhat“wasmissed”inthedesignphase.Thepost-mortemanalysisoftheseeventsisfacilitatedwiththeexistingtechnologyofdisturbancerecordings（viafaultdisturbancerecordersorembeddedinnumericalrelays）.Thisprocessresultsinaccumulationofexperiencethatpassesfromonegenerationofengineerstothenext.

Animportantchallengeforeducatorsisthetrainingofstudentstobecomeeffectiveprotectiverelayingengineers.Studentsmustbeprovidedwithanunderstandingofrelayingtechnologythatencompassesthemultiplicityoftherelayingfunctions,communications,protocols,andautomation.Inaddition,adeepunderstandingofpowersystemoperationandbehaviorduringdisturbancesisnecessaryforcorrectrelayingapplications.Intoday’scrowdedcurricula,thechallengeistoachievethistrainingwithinaveryshortperiodoftime,forexample,onesemester.Thispaperpresentsanapproachtomeetthischallenge.Specifically,weproposetheconceptofthevirtualpowersystemforthepurposeofteachingstudentsthecomplextopicofprotectiverelayingwithinashortperiodoftime.

Thevirtualpowersystemapproachispossiblebecauseoftwofactors:

a）recentdevelopmentsinsoftwareengineeringandvisualizationofpowersystemdynamicresponses,andb）thenewgenerationofpowersystemdigital-object-orientedrelays.Specifically,itispossibletointegratesimulationofthepowersystem,visualization,andanimationofrelayresponseandrelaytestingwithinavirtualenvironment.Thisapproachpermitsstudentstostudycomplexoperationofpowersystemsandsimultaneouslyobserverelayresponsewithprecisionandinashorttime.

Thepaperisorganizedasfollows:

First,abriefdescriptionofthevirtualpowersystemisprovided.Next,themathematicalmodelstoenablethefeaturesofthevirtualpowersystemarepresentedtogetherwiththemodelingapproachforrelaysandrelayinstrumentation.Finally,fewsamplesofapplicationsofthistoolforeducationalpurposesarepresented.

II.VIRTUALPOWERSYSTEM

Thevirtualpowersystemintegratesanumberofapplicationsoftwareinamultitaskingenvironmentviaaunifiedgraphicaluserinterface.Theapplicationsoftwareincludesa）adynamicpowersystemsimulator,b）relayobjects,c）relayinstrumentationobjects,andd）animationandvisualizationobjects.Thevirtualpowersystemhasthefollowingfeatures:

1）continuoustime-domainsimulationofthesystemunderstudy;

2）abilitytomodify（orfault）thesystemunderstudyduringthesimulation,andimmediatelyobservetheeffectsofthechanges;

3）advancedoutputdatavisualizationoptionssuchasanimated2-Dor3-Ddisplaysthatillustratetheoperationofanydeviceinthesystemunderstudy.

Theabovepropertiesarefundamentalforavirtualenvironmentintendedforthestudyofprotectiverelaying.Thefirstpropertyguaranteestheuninterruptedoperationofthesystemunderstudyinthesamewayasinaphysicallaboratory:

onceasystemhasbeenassembled,itwillcontinuetooperate.Thesecondpropertyguaranteestheabilitytoconnectanddisconnectdevicesintothesystemwithoutinterruptingthesimulationofthesystemortoapplydisturbancessuchasafault.Thispropertyduplicatesthecapabilityofphysicallaboratorieswhereonecanconnectacomponenttothephysicalsystemandobservethereactionimmediately（e.g.,connectinganewrelaytothesystemandobservingtheoperationoftheprotectiverelayinglogic,applyingadisturbanceandobservingthetransientsaswellastherelaylogictransients,etc.）.Thethirdpropertyduplicatestheabilitytoobservethesimulatedsystemoperation,inasimilarwayasinaphysicallaboratory.Unlikethephysicallaboratorywhereonecannotobservetheinternaloperationofarelay,motor,etc.,thevirtualpowersystemhasthecapabilitytoprovideavisualizationandanimationoftheinternal“workings”ofarelay,motor,etc.Thiscapabilitytoanimateandvisualizetheinternal“workings”ofarelay,aninstrumentationchannel,oranyotherdevicehassubstantialeducationalvalue.

ThevirtualpowersystemimplementationisbasedontheMSWindowsmultidocument-viewarchitecture.Eachdocumentobjectconstructsasinglesolverobject,whichhandlesthesimulationcomputations.Thesimulatedsystemisrepresentedbyasetofobjects—oneforeachsystemdevice（i.e.generators,motors,transmissionlines,relays,etc）.Thedocumentobjectcangenerateanynumberofviewwindowobjects.Twobasicviewclassesareavailable:

a）schematicviewsandb）resultvisualizationviews.Schematicviewobjectsallowtheusertodefinethesimulatedsystemconnectivitygraphically,bymanipulatingasinglelinediagramusingthemouse.Resultvisualizationviewsallowtheusertoobservecalculatedresultsinavarietyofways.Severaltypesofresultvisualizationviewsaresupportedandwillbediscussedlater.

Fig.1illustratestheorganizationofdeviceobjects,networksolver,andviewobjectsandtheirinteractions.Thenetworksolverobjectisthebasicenginethatprovidesthetime-domainsolutionofthedeviceoperatingconditions.Tomaintainobjectorientation,eachdeviceisrepresentedwithageneralizedmathematicalmodelofaspecificstructure,thealgebraiccompanionform（ACF）.Themathematicsofthealgebraiccompanionformaredescribedinthenextsection.Implementationwise,thenetworksolverisanindependentbackgroundcomputationalthread,allowingbothschematiceditorandvisualizationviewstobeactiveduringthesimulation.Thenetworksolvercontinuouslyupdatestheoperatingstatesofthedevicesand“feeds”allotherapplications,suchasvisualizationviews,etc.

Thenetworksolverspeedisuserselected,thusallowingspeeding-uporslowing-downthevisualizationandanimationspeed.Themultitaskingenvironmentpermitssystemtopologychanges,deviceparameterchanges,orconnectionofnewdevices（motors,faults）tothesystemduringthesimulation.Inthisway,theusercanimmediatelyobservethesystemresponseinthevisualizationviews.

Thenetworksolverinterfaceswiththedeviceobjects.Thisinterfacerequiresatminimumthreevirtualfunctions:

Initialization:

Thesolvercallsthisfunctiononcebeforethesimulationstarts.Itinitializesalldevice-dependentparametersandmodelsneededduringthesimulation.

Reinitialization:

Thesolvercallsthisfunctionanytimetheusermodifiesanydeviceparameter.Itsfunctionissimilartotheinitializationvirtualfunction.

Timestep:

Thesolvercallsthisfunctionateverytimestepofthetime-domainsimulation.Ittransfersthesolutionfromtheprevioustimesteptothedeviceobjectandupdatesthealgebraiccompanionformofthedeviceforthe