Dynamic-wind-turbine-models-in-power-system-simula

Risø-R-1400(EN)DynamicwindturbinemodelsinpowersystemsimulationtoolDIgSILENTAncaD.Hansen,ClemensJauch,PoulSørensen,FlorinIov,FredeBlaabjergRisøNationalLaboratory,RoskildeDecember2003ContentsPreface51Introduction62WindturbinemodellinginDIgSILENT72.1Powersystemsimulationtool-DIgSILENT72.2Built-inmodelsinDIgSILENT82.2.1Electricalmachinery82.2.1.1Squirrelcageinductiongenerator(SCIG)92.2.1.2Doubly-fedinductiongenerator(DFIG)122.2.2Powerconverters142.2.3Transformer162.3DSLmodelsofwindturbineinDIgSILENT182.3.1InitialisationissuesonthewindturbineDSLmodels192.3.2Mechanicalmodel212.3.3Aerodynamicmodel242.3.4Windmodel292.3.5Capacitor-bankcontrolmodel313Activestallwindturbineconcept323.1ActiveStallControlStrategy333.1.1PowerLimitation333.1.2PowerOptimisation343.1.3Transitionbetweenpowerlimitationandpoweroptimisationmode343.2Activestallpowercontroller353.2.1Poweroptimisation353.2.1.1Generatingθlookuptable353.2.2Powerlimitation373.2.3Transitionbetweenoptimisationandlimitation383.2.4Pitchanglecontrolsystem393.2.4.1Subsystemtoavoidunnecessarypitching413.2.4.2Overpowerprotection413.3Windturbinecontrollerimplementationinpowersystemsimulationtool423.3.1Poweroptimisation433.3.2Powerlimitation443.4Simulations453.4.1ParameterSettings453.4.2Poweroptimisation463.4.3Transitionbetweenoptimisationandlimitation473.4.4Powerlimitation484Variablepitch,variablespeedwindturbineconcept504.1Variablespeedwindturbinecharacteristics514.2Doubly-fedinductiongeneratorcharacteristics524.3TheoverallcontrolsystemofavariablespeedwindturbinewithDFIG544.4Doubly-fedinductiongeneratorcontrol574.4.1Systemreferenceframes57Risø-R-1400(EN)34.4.2ControlconfigurationofDFIGinDIgSILENT584.4.3Rotorsideconvertercontrol594.4.4Gridsideconvertercontrol624.5Windturbinecontrol644.5.1Controlstrategies644.6Windturbinecontrolsystem674.6.1Speedcontroller684.6.2Powerlimitationcontrollerwithgainscheduling694.6.3Cross-coupledcontrol714.7Simulationresults715CONCLUSIONS76Acknowledgements78REFERENCES794Risø-R-1400(EN)PrefaceThisreportdescribestheresultsoftheprojecttitled“SimulationPlatformtomodel,optimizeanddesignwindturbines”.TheprojectwascarriedoutinacooperationbetweenRisøNationalLaboratoryandAalborgUniversity,fundedbytheDanishEnergyAgencycontractnumberENS-1363/01-0013.Risø-R-1400(EN)51IntroductionThepresentreportdescribesthedynamicwindturbinemodelsimple-mentedinthepowersystemsimulationtoolDIgSILENT(Version12.0),whichprovidesbothanextensivelibraryforgridcomponentsandadynamicsimula-tionlanguage(DSL)forthemodellingofeachwindturbinecomponent.ThedevelopmentofthesemodelsisapartoftheresultsofanationalDanishre-searchproject,whoseoverallobjectiveistocreateamodeldatabaseofelectri-calcomponentsmainly,indifferentsimulationtoolsinordertoenhancethede-signandtheoptimisationofthewindturbines.Thedevelopedmodeldatabaseisabletosupporttheanalysisoftheinterac-tionbetweenthemechanicalstructureofthewindturbineandtheelectricalgridbothduringnormaloperationofthewindturbineandduringtransientgridfaultevents.Suchmodelsmakeitpossibletosimulatethedynamicinteractionbe-tweenawindturbine/windfarmandapowersystem.Theyenableboththepo-tentialwindturbineownersandthegridutilitytechnicalstafftoperformthenecessarystudiesbeforeinvestingandconnectingwindturbines(farms)tothegrid.Simulationofthewindturbineinteractionwiththegridmaythusprovidevaluableinformationandmayevenlowertheoverallgridconnectioncosts.Themotivationforthisresearchprojectistheever-increasingwindpowerpenetrationintopowernetworks.InrecentyearsthetrendhasbeenmovedfrominstallationswithafewwindturbinestotheplanningoflargewindfarmswithseveralhundredMWofcapacity.Thisincreasedandconcentratedpenetrationmakesthepowernetworkmoredependenton,andvulnerableto,thewinden-ergyproduction.Thissituationmeansthatfuturewindfarmsmustbeabletoreplaceconventionalpowerstations,andthusbeactivecontrollableelementsinthepowersupplynetwork.Inotherwords,windfarmsmustdeveloppowerplantcharacteristics(SørensenP.etal.,2000).ThetwoutilitiesresponsibleforthetransmissionsystemsinDenmark,EltraandElkraftSystem,haveissuedrequirements(Eltra,2000)thatfocusontheinfluenceofwindfarmsongridstabilityandpowerquality,andonthecontrolcapabilitiesofwindfarms.Anotherconsequenceoftheincreasedfuturesizeofwindfarmsisthatthelargewindfarmswillbeconnecteddirectlytothehighvoltagetransmissiongrid.Untilnow,windturbinesandwindfarmshavebeenconnectedtothedis-tributionsystem,whichtypicallyhaseither10/20kVor50/60kVgrids.There-fore,themainfocushasbeenontheinfluenceofthewindfarmsonthepowerqualityofthedistributionsystem.ForexampleinDenmark,thishasbeenregu-latedbytheDanishUtilitiesResearchInstitute(DEFU)requirementsforgridconnectionofwindturbinestothedistributionsystem(DEFU,1998).However,thetransmissionsystemoperatorsinDenmarknowissuemorestrictconnectionrequirementsforlargewindfarmsiftheyareconnecteddirectlytothetransmis-sionsystem.Moreover,nationalstandardsforpowerqualityofwindturbineshaverecentlybeensupplementedbyanewstandardformeasurementandas-sessmentofpowerqualityofgridconnectedwindturbines,namely(IEC61400-21,2001).Alargepar