礦井3～10kV電網(wǎng)接地選線研究.pdf

1、華中科技大學(xué)碩士學(xué)位論文礦井3～10kV電網(wǎng)接地選線研究姓名：陳建華申請(qǐng)學(xué)位級(jí)別：碩士專業(yè)：電氣工程指導(dǎo)教師：劉沛20051105華中科技大學(xué)碩士學(xué)位論文ABSTRACTAtpresent，thedistributionpowersystemofmineinourcountryalwaysadoptsinefficientgroundedmethodsWhenasinglephasefaultoccurs，thefaultcurrent

2、isSOsmallthatthefaultcharacteristicsarehardlydistinguishedThenetworksarecalledNeutralUneffectualGroundedSystemfrOGS)TheNUGS’unobviousfaultcharacteristicsbringdifficultyforfaultdetectionandfaultedlineselectionThisthesispr

3、oceedswiththeanalysisofthecurrentandvoltageafterasinglephasefaultinNUGS，andthendiscussesthedifferencesoffaultlineselectionschemesamongnetworkswithdifferentgroundedmethodsSomefaultselectionschemesaresummarizedAswaveletCan

4、analyzesignalsintime—scaleandfrequencyscalepartially，ithasbeenusedinvariousareasAzero—sequencetransientcurrentsfaultlinedetectingcriterionbasedonwavelettransformhasbeenbrou曲tforward，whosewaveletfunctionisB—splinewaveletT

5、hen，anewschemeforthefaultedlineselectionbasedonnegativesequencetransientcurrentisproposedWhenasingle—phasefaultOccurs，themagnitudeofnegativesequencetransientcurrentofthefaultedlineisthemaximalofall，SOitcanbeeasilychosenA

6、TPsimulationdemonstratedthatthisarithmeticisimmunetothevariationsoflineparametersandthechangesofcompensatinginductanceMoreover，itcanendureverylargefaultresistanceHowever，itCan’tidentifysingle—phasefaultofthebusFinally，an

7、ewprincipleforfeedergroundingfaultprotectionbasedonzerosequencecompensatingadmittanceisproposedItcanbeappliedeasilyinfeederrelaysandimplementedinlocalcontrolunitsbymeasuringthezerosequencefundamentalvoltageandcurrentItim

8、provestheperformanceoftraditionalgroundingfaultrelaysindifficultimplementationandpoorreliabilityKeywords：PowersystemofmineSingle—phasefaultWavelettransformZerosequencetransientcurrentNegativesequencetransientcurrentZeros