Thesis - Islanding Detection

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1、NegativeSequenceImpedanceMeasurementforDistributedGeneratorIslandingDetectionbyMichaelC.WrinchB.Sc.,TheUniversityofBritishColumbia,1995B.A.Sc.,MemorialUniversityofNewfoundland,2000M.A.Sc.,MemorialUniversityofNewfoundland,2002ATHESISSUBMITTEDINPARTIALFULFILMENTOFTHEREQUIREMENTSFORTHEDEG

2、REEOFDoctorofPhilosophyinTheFacultyofGraduateStudies(ElectricalandComputerEngineering)TheUniversityOfBritishColumbia(Vancouver)December,2008cMichaelC.Wrinch2008AbstractThisthesispresentsamethodofdetectingelectricalislandsinlowvoltagedistributedgeneratornet-worksbymeasuringnegativeseque

3、nceimpedancedifferencesbetweenislandedandutilityconnections.Extensivetestingwasconductedonacommercialbuildingand25kVdistributedgeneratorfednetworkbymeasuringnaturallyoccurringandartificiallyinjectednegativesequencecomponents.Similarly,thistechniquewastestedusingtheIEEE399-1990bustestcas

4、eusingtheEMTPsoftware.Thepracticalmeasurementshavebeenmatchedtosimulationswherefurthersystemperformancecharacteristicsofdetectingpowersystemislandshasbeensuccessfullydemonstrated.Measuredresultsindicatethatun-balancedloadconditionsarenaturallyoccurringandreadilymeasurablewhiledeliberat

5、elyunbalancedloadscanincreasetheaccuracyofnegativesequenceimpedanceislandingdetection.Thetypicallylownegativesequenceimpedanceofinductionmotorswasfoundtohaveonlyasmalleffectinlowvoltagebusses,thoughlargemachinescaneffectthethresholdsettings.Carefulplacementoftheislanddetectorisrequired

6、inthesesituations.Thenegativesequenceimpedancemeasurementmethodisanimprove-mentonpreviousimpedancemeasurementtechniquesforislandingdetectionduetoitsaccuracy,anddistinctlylargethresholdwindowwhichhavechallengedpreviousimpedancebasedislandingdetectiontechniques.iiTableofContentsAbstract.

7、.............................................iiTableofContents.........................................iiiListofTables............................................viiListofFigures...........................................viiiAcronyms.............................................xiAckn