一種新型微機(jī)變壓器保護(hù)的研究.pdf

1、天津大學(xué)碩士學(xué)位論文一種新型微機(jī)變壓器保護(hù)的研究姓名：梅云申請(qǐng)學(xué)位級(jí)別：碩士專業(yè)：電力系統(tǒng)及其自動(dòng)化指導(dǎo)教師：李永麗2002.1.1、ABSTRACTPowertransformerisoneofthemostimportantelectricalelementsinthepowersystemanditsreliableoperationhasgreatsignificanceforpowersupplyandnormaloperat

2、ionofthesystemSince1990’S，thecorrectoperatingrateofprotectiverelaysfor220kvtransformersandaboveislowerthan70％inChina，SOimprovementtocurrentprotectivetheoryisquitenecessaryAimingattheshortcomingofthetraditionaldifferentia

3、lprotectionthatitwillmisoperateunderthecondRionofinrushcurrent，thispaperintroducesthesecondaryharmonicprinciple，theincontinuousangleprincipleandthesymmetricalwaveformprinciple，whichareallbasedonthedifferentcharacteristic

4、softhewaveformofthefaultcurrentandtheinrushcurrentAnddetailanalysisaremadewiththesymmetricalwaveformprincipleThispaperalsopointsoutthatthesymmetricalwaveformprincipleearl’tdistinguishthefaultcurrentandtheinrushcurrentwhe

5、nthecurrentisdistortedseverelyduringCTsaturationThispaperalsoproposesakindoffeasibleprotectiveschemeforpowertransformersByanalyzingthepositivesequenceandthenegativesequencenetworkmodelsondifferentfaultstates，itcandisting

6、uishintemalfaults，externalfaultsandinrushcurrentoftransformers，basedonthedifferentdirectionsofsequencepowerswhicharecomputedwithpurefaultcomponentInstantaneoussamplesaretakentocalculatethepositiveandthenegativesequencepo

7、werstospeedtheoperationtimeFinaljudgmentCanbemadeinaquarterofacycleThisalgorithmisverysensitiveandhasawideoperationrangeAlotofATPsimulationsverifythecorrectnessofthisschemeAtlast，thehardwareandthesoftwareofatransformerpr

8、otectiondeviceisexplainedwhichisappliedtothetransformerof110kvThemaintheoriescontain：differentialprotection，overcurrentprotection，zero。sequenceovercurrentprotectionandoverloadprotection，etcDynamicsimulationtestreportisgi