电能设备EMC(英文)

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1、Section1EMCOFELECTRICALPOWEREQUIPMENTMUTUALINDUCTANCEBETWEENWIRESINHELICALLYTWISTEDPOWERCABLESBerndW.Jaekel,GermanySiemensAG,AutomationandDrives,Germany,e-mail:bernd.jaekel@siemens.comAbstract.Thearrangementoftheconductorsinamulti-corepowercableleadstoasituationwherevariouscon

2、ductorloopsarebuiltup.Oneorseveralloopsareformedbythephaseandneutralconductorswiththeoperationalcurrentflowingintheseconductors.Afurtherloopisbuiltupbytheprotectiveearthconductorwhichisconnectedtotheequipotentialbondingsystematseverallocations.Theareaofthisloopisessentiallyarr

3、angedoutsideofthepowercable.Theinductivecouplingfromthephaseconductorloopsintothatloopcausescommonmodevoltagesintheprotectiveearthsystemwithconsequentcommonmodecurrents.Itcanbedemonstratedthatthiseffecteventakesplaceinthecaseofbalancedphasecurrentsinthecable.Numericalsimulatio

4、nsandparameterstudieswerecarriedoutinordertodescribethiseffectquantitativelyandtoinvestigatetheinfluenceofdifferentcableparametersontotheresultingcommonmodevoltages.53IntroductionPowercablesrepresentcomponentsofanentirepowersupplynetworkwhichcanbecarriedoutindifferenttypes.Ifa

5、nearthedsystemisrequired,i.e.asystemwhichisconnectedtothelocalreferenceearth,mainlytwotypesofsupplynetworkscanbedistinguished:TN-CandTN-S.FromanEMCpointofviewaTN-Spowernetworkshoulddefinitelybepreferred[1].Inthistypeofnetworktheneutralandprotectiveearth(PE)conductorsarestrictl

6、yseparatedexceptatonenetpointwherebothconductorsareconnected,normallyatthetransformerortheswitchgear.Thistypeofinstallationpreventsthatanyoperationalcurrentsflowoutsideofthephaseandneutralconductors.Nocablenetcurrentsshouldexistandthereforetheequipotentialbondingsystemisgenera

7、llyassumedtobefreeofanyoperationalcurrents.ButwhenlookinginmoredetailatthistypeofnetworkandatthephysicalstructureofpowercablessomephysicalmechanismscanbeidentifiedwhichneverthelessleadtothegenerationofcommonmodevoltagesandcommonmodecurrentseveninthecaseofbalancedloadedTN-Spowe

8、rnetsystems.LowVoltagePowerCablesMulti-corelowvoltagepowercab