Thesis - On-line voltage stability assessment of power syste

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1、TampereenteknillinenkorkeakouluJulkaisuja344TampereUniversityofTechnologyPublications344SamiRepoOn-lineVoltageStabilityAssessmentofPowerSystem—AnApproachofBlack-boxModellingTampere2001iABSTRACTThemanagementofpowersystemshasbecomemoredifficultthanearlierbecausepowersystemsareope

2、ratedclosertosecuritylimits,environmentalconstraintsrestricttheexpansionoftransmissionnetwork,theneedforlongdistancepowertransfershasincreasedandfeweroperatorsareengagedinthesupervisionandoperationofpowersystems.Voltageinstabilityhasbecomeamajorconcerninmanypowersystemsandmanyb

3、lackoutshavebeenreported,wherethereasonhasbeenvoltageinstability.On-linevoltagestabilityassessmentiscommonlybasedonablack-boxmodelling.Traditionallythemodelhasbeenatwo-dimensionalsecurityboundary,whichisbasedontabulationofdata.Theideaofthemodel-basedapproachpresentedinthisstudy

4、istogeneralisethesecurityboundarymethodandtotakeintoaccounttheuncertaintyrelatedtopowersystemoperation.Theterm“model-basedapproach”meansinthisthesisanapproachwhichisbasedonblack-boxmodels.Themodel-basedapproachdoesnotreplacetraditionalanalysismethods,ratherthesemethodsareurgent

5、lyneededattheoff-linecomputationstepoftheapproach.Thecomputationofthevoltagestabilitymarginistime-consumingandthatiswhythesemethodscannotbeusedinon-lineapplications.Theobjectiveofthestudywastodevelopamethodtobeapplicableinpracticeforon-linevoltagestabilityassessmentoflong-terml

6、arge-disturbancevoltagestabilitybasedonblack-boxmodel.Thebasisoftheapproachisappropriatemodellingofpowersystemvoltagestabilityandcomputationofthemostcriticalvoltagestabilitymargins.Alargenumberofpowersystemoperationpointsandthemostcriticalvoltagestabilitymarginsarecomputedtocre

7、atethemodel.Anessentialpartofmodelcreationistheselectionandextractionofmodelinputs,onwhichtheaccuracyofthemodelismainlybased.Thisthesisevincesnewideasforon-linevoltagestabilityassessmentofblack-boxmodel.Therequirementsandtheproposedsolutionofallstepsarepresentedtoprovideastepby

8、stepprocedurefortheuse.Thethesisdescribesfirsttimeanap