基于故障分量的T接輸電線路電流差動(dòng)保護(hù)的研究.pdf

1、天津大學(xué)碩士學(xué)位論文基于故障分量的T接輸電線路電流差動(dòng)保護(hù)的研究姓名：羅濤申請學(xué)位級別：碩士專業(yè)：電力系統(tǒng)及其自動(dòng)化指導(dǎo)教師：李斌201112ABSTRACTWiththeconstructionanddevelopmentoflargepowersystem，TtypetransmissionlinesarewidelyusedinextrahighvoltagepowersysteminChinaComparedwithtwo—te

2、rminaltransmissionlines，therearemanydifferentcharacteristicsinTtypetransmissionlinesBecauseloadcurrentmayflowoutinthecaseofinternalfaultandCTisapttosaturateinthecaseofexternalfaultinTtypetransmissionline，therearesomeunav

3、oidabledefectionsfortheprinciplesoftwoterminaltransmissionlinedifferentialprotectionwhenitisusedinTtypetransmissionlineTherefore，itisimportanttesearchondifferentialprotectionofTtypetransmissionlineConventionalcurrentdiff

4、erentialprotectionusethepercentagerestraintprinciple，itCanimprovethesensitivitywhileensurethesecurityofdifferentialprotectionwiththesetofbrakeHoweverthetraditionalpercentagerestraintcriteriahaveaseriesofinherentdisadvant

5、ages，inwhichthemainshortcomingsisdistributionbythelongtermimpactofalargecapacitivecurrent，thefailurecausedbytheloadcurrentsandtransitionresistanceinintemalfault，beapttofailwhenthetransformersaturatesinextemalfault，andSOo

6、nInaddition，itsbrakingcoefficient’Sselectionisalsoacontradiction，itwilllowerthesensitivitywhenthevalueistoobigandwillaffectthereliabilitywhenthevalueistoosmallAccordingtothedisadvantagesofconventionaldifferentialprotecti

7、onofTtypetransmissionline，thepaperproposesanovelprincipleofdifferentialprotectionwhichisbasedonfaultcomponentCurrentphasedifferentialphaseisintroducedintealizationofcurrentdifferentialprotectionRestraintunitoftheproposed

8、principletakestheroleofdriveandrestraintrespectivelyinthecaseofintemalandexternalfaultsTherefore，thesensitivityandreliabilityofdifferentialprotectionareimprovedsimultaneouslyItcarlmeetthedemandofthesensitivityforinternal

9、faultandsecurityforexternalfaultatthesametimeThecoefficientofbrakingCanbechoseninfinitelyBythedetaildiscussesofpolarcoordinatessystemsandrectangularcoordinates，itisprovedthatthenewtheoryalsohashighsensitivityandreliabili

10、tyMeanwhile，thecomparewiththeconventionalpercentagerestraintprinciplehasprovedthatthenewcriteriahaveagoodperformancewhenthe仃ansformersaturatesandwhenthetransitionresistancehaveabigvalueInordertofurtherenhancetheperforman