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ID:7288313
大小:15.75 MB
页数:300页
时间:2018-02-10
《high voltage engineering and testing 2nd edition(上)》由会员上传分享,免费在线阅读,更多相关内容在工程资料-天天文库。
1、ChapterIElectricpowertransmissionanddistributionsystemsI.A.Erinmez1.1Natureanddevelopmentoftransmissionanddistributionsystems1.1.INatureoftransmissionanddistributionsystemsToday,inallcountriesintheworldthatutiliseelectricityasanefficientsourceoflightandenergy,someformofatransmissionan
2、ddistributionsystemexists.Bothsystemscarryelectriccurrent,albeitatdifferentvolt-agesandtheyareconnectedtoeachother.Theyarepartofthebulktransportanddistributionsystemthatessentiallydeliversanddistributestheelectricalenergy,convertedfromprimaryenergysources,totheendusers.Theonlycleardif
3、ferencesbetweenthetwosystemsisbasedontheperceptionoftheirenduseandfunctionality.Transmissionsystemsprovidethebulktransportpathsforelectricalenergyfromgenerationcentreslocatedclosetotheprimaryenergysourcestothemajorloadcentreswithinalargegeographicalarea,thusfacilitatingeconomicandeffi
4、cientbulkpowertransfer.Ontheotherhanddistributionsystemsareconcernedwiththedeliveryofelectricalenergytoindividualcustomerswithinasmallergeo-graphicalarea.Inthisrespectadistributionsystemmayhaveanumberofdeliverypointstoitsmajorloadcentres,fromoneormoretransmissionsystemsand/orelementso
5、fatransmissionsystem,thefinalshapeofthesystemstructurebeingdependentonthemagnitudeandthepatternofdemandwithinitsgeographicalarea.Itisalsousualfortransmissionsystemstobeinterconnectedtoenablesharedeconomicbenefitsandoperationalaccesstogeneratingcapacity.10Highvoltageengineeringandtesti
6、ngGenerallymoderntransmissionsystemstransportelectricalenergybyalternatingcurrent(AC)atafrequencyof50or60cyclespersecondoperatingatvoltagesof220kVandabove,withotherstandardvoltagesof275kV,330kV,400kV,500kV,765kVand1000kV.Assystemsdevelop,eachtimeanewtransmissionvoltageisaddedthelowest
7、trans-missionvoltagelevelrevertstoplaymoreofadistributionnetworkrole.Forexample,the132kVtransmissionnetworkdevelopedintheearlydaysintheUKassumedadistributionroleaftertheadditionof275and400kVtransmissionnetworks.Itisusualforoneormoreofthesestand-ardvoltagenetworkstobeemployedwithtransf
8、ormer
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