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英文文献CirtcuitBreakersAcircuitbreakerismechanicalswitchingdevicecapableofmaking,andbreakingcurrentsundernormalcircuitconditionsandalsomaking.carringforaspecifiedtime,andmediujminwhichcircuitinterruptionisperformedmaybedesignatedbyasuitableprefix,forexample,air-blastcircuitbreaker,oilcircuitbreaker.Thecircuitbreakerscurrentlyinusecanbedlassifiedintothefollowingcategoriesaccordingtothearc-quenchingprinciples:airswetchesoelciryitbreakers,minmum-oilcircuitbreakers,air-blastcircuitbreakers,themageneticaircircuitbreakers,minimum-oilcircuitbreakers,aer-blastcircuitbreakers,thebyvoltage,insulationlevelcurrent,interruptingcapabilities,transientrecoverycoltage,interruptingtiome,andtripdelay.Thenameplateonacircuitbreakerusuallyindicates:１.Themaximumsteady-statecurrentitcancarry,2.Themaximuminterruptingcurrent,3.Themaximumlinevoltage,4.Theinterruptingtimeincycles,Theinterruptingtimeinmaylastform3to8cyclesona60Hzsystem.Tointerrubtlargecurrentsquickly,wehavetoensurerapidcooling.High-speedinterruptionlunitsthedamagetransmissionlinesandequipmentand,equallyimportant,ithelpstomainmainthestabilityofthesystemwheneveracontingencyoccurs.Themainpartsofacircuitbreakerareusually:arc-quenchingchamber(orinterrupterwithmovingandfixedcontacts)operatingmechanismandsupportingstructures.AirSwitches-Withincreasingcurrentsandvoltages,spring-actiondrivingmechanismsweredevelopedtoreducecontactburingbyfaster-openingoperation.Later,maincontactswerefittedwitharcingcontactsofspecialmaterialandshape,whichopendafterandclosedbeforethemaincontacts.Furtherimprovementsoftheairswitchwerethebursh-typecontactwithawipingandcleaningfunction,theinsulatingbarrierleadingtoarcchutes,andblowoutcoilswithexcellentarc-extinguishingproperties.Thesefeatures,aswellasthehorngapcontact,arestillinuseinlowvoltageasanddebreakers.OilCircuitBreakerAround1900,inordertocopewiththenewrequirementfor“interruptingcapacity”,ACswitcheswereimmersedinatankofoil.Isveryeffectiveinquenchingthearcandestablishingtheopenbreakaftercurrentzero.Deiongrids,oil-blastfeatures,pressure-tightjointsandvents,newoperatingmechanisims,andmultipleinterrupterwereintroucedoverseveraldecadestomaketheoilcircuitbreakerareliableapparatusforsystemvoltageupto362Kv.LingtingprotectionThethunderandlightningprotectstoconnecttheground;Connectthegroundtoavoidthethunderthemostimportantlinkofthetechnique,ignoreisashotthunder,respondthethunderofthethunderorotherform,andavoidthethunderworkmostallofsendintotheearththethunderelectriccurrent.Storethethunderenergytobehavethetypetobuildthe,currenttechnologytostillreachtonotarrive,andthereforehavenothereasonablebutgoodconnectthegroundequiptoisimpossibletospeakabouttodefendthethunder.Thereforesaythedesign,theconstructionisveryhighstandardtoconnectthegroundsystemisaheavyinsidethatdefendthunder'sworkitheavy.HighelectricpotentialthatForlongtime,peoplehaveanillusion,andthinkthatconnectthegroundelectricresistancemoresmallavoidthethunderresultandthenmorelike,quiltobjectthatprotectsafety.Certainlytheelectricresistanceismorethesmallismorequick,strikebylightningtoreservetimemoreshort,theriskismoresmall,electricvoltageofitsstride,getintouchwiththetheelectricvoltageproducethemachinetoothemorethe?But,constructionthatthefulfillmentproofofnearandmorethanteninthelastyearses,withitssaythatconnecttheworthimportanceofgroundelectricresistance,notequaltosaythatconnectthegroundtoequipmorereasonable,importanceElectricityequipments,demandvarietythatnow'scity,thereislotsofinabuildinginsidenotthecongenialityconnectthegrounddevice,ifavoidthethundertoconnecttheground,electricitythesafetytoconnecttheground,ACpowertheworktoconnecttheground,correspondenceandcalculatorsystemtoconnecttheground,accordingtothefulfillmentproof,totallyusetoconnectthegroundisanapplicationmostforextensiveconnectthelocaltype.ThatA,theindependenceconnecttheground:Asabovepartfordemandforspeakofingconnectingthegroundof,alldistinguishtoindependentlyestablishtheowntoconnectthegroundsystem,andthiskindofconnectthelocaltypetocalltheindependencetoconnecttheground.Itsadvantageiseachsystemandcan'tresultinthemutualinterference,andthisisparticularlyimportanttocorrespondencessystems.Buttheadoptionindependencethatnetworkeasilywerestrikebylightningedisbad,sobesideshavetodefendtoexplodethedangerousenvironmentrequestingtomustwanttheadoptiontheindependenceofavoidthethundermethodgenerallynotlayclaimtothewaytoconnecttheground.Two,totallyusetoconnecttheground:Alsocallunifytoconnecttheground.Theeachsystemthatitconnectthegroundthedemandunifiestoreceiveaconnectthegroundtoequiptop,orisoriginallyeachsystemofconnectthegrounddevicetopasstheundergroundtoperhapsanduplink,makethemtheelectricityforbecomingofitstoconnectthegroundtounifythegroundnetwithmetalsconductor,likethisofconnectthelocaltypeistototallyusetoconnecttheground.itiscurrenttousetoconnectthegroundtotallyappliedthemostextensiveconnectthelocaltype.EachsystemthatThree,connecttheground1:00:Methodthatconnectingthegroundlinetoreceivetoconnectthesamepointorsamemetalsflatsurfaceoflineofgroundmoth