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1、.本科毕业设计（论文）中英文对照翻译院（系部）电气工程与自动化学院专业名称电气工程及其自动化年级班级 03级2班学生姓名 指导老师2007年6月10日23UnattendedsubstationandsubstationautomationThedevelopmentofautomaticreclosingmadetheunattendedsubstationpractical.Automaticoperation,withoutthecontinuouspresenceofanattendant(operator),
2、wasfirsttriedonthesynchronousconvertersubstationssupplyinganinterurbanelectricrailwayin1914.Intheearly1920s,thedevelopmentofautomaticreclosing,protectiverelays,andmeansforautomaticcontrolofvoltagemadeitpossibleforacsubstationstobecompletelyautomatic.Duringtheper
3、iodwhenthesubstationshadtobecontrolledmanually,itwasnecessarythattheyhandleenoughpowertojustifytheoperator`swages.Thisdictatedlargestations,frequentlyservinglargeareasbymeansofmanyfeeders.Thefeedersthatservedthemoredistantpartsofanareahadtogoalongwaybeforetheypi
4、ckedupanyload.Furthermore,astheloadonalargesubstationgrows,transformercapacityhastobeadded.Thisincreasestheshort-circuitcurrentonthesecondarysidesometimestheshort-circuitcapacityexceedstheinterruptingcapacityofthecircuitbreakersalreadyinstalled.Appropriateremedi
5、esincludebussectionalizing,theinstallationofreactorsorsomecombinationofthetwo.Suchmeasuresarefrequentlyexpensiveandinconvenientandtheyconstituteanundesirablelimitationonoperatingflexibility.Oncetheunattendedsubstationbecameareality,thesubstationcouldbemadesmalle
6、r.Locatednearertheload,andlongfeederswerenolongernecessary.Thisnewmethodofdistributionhadbecomeavailablesinceloadgrowthcouldnowbeaccommodatedbyinstalling23anothersubstationthatcouldcarrypartsofthearealoadsformerlycarriedbyadjacentsubstations.Usually,thereisnoint
7、erconnectionbetweenthecircuitsenergizedbythevarioussubstations.Consequently,thereisnoincreaseinshort-circuitseverity.however,atthedistributionlevel,tieswitchesareusedtoswitchfeedersorfeedersectionsbetweentransformersinthesamestationortoadjacentsubstationsforsubs
8、tationtransformerloadmanagement.Automaticcontrolhasbeenappliedtolargerandlargersubstations,andtomanyhydroelectricgeneratingstations.Itisalsousedonindividualcircuitsan
