电力系统外文英语文献资料.doc

电力系统外文英语文献资料.doc

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ElectricPowerSystem

Electricalpowersystemreferstoremovepowerandelectricpartsofthepart,Itincludessubstation,powerstationanddistribution.Theroleofthepowergridisconnectedpowerplantsandusersandwiththeminimumtransmissionanddistributionnetworkdisturbancethroughtransportpower,withthehighestefficiencyandpossibilitywillvoltageandfrequencyofthepowertransmissiontotheuserfixed.Gridcanbedividedintoseverallevelsbasedontheoperatingvoltagetransmissionsystem,substructure,transmissionsystemanddistributionsystem,thehighestlevelofvoltagetransmissionsystemisZhuWangJiaorconsideredthehighpowergrids.Fromthetwoaspectsoffunctionandoperation,powercanberoughlydividedintotwoparts,thetransmissionsystemandsubstation.Thefarthestfromthemaximumoutputpowerandthepowerofthehighestvoltagegradeusuallythroughlinetoload.Secondarytransmissionusuallyreferstothetransmissionanddistributionsystemisthatpartofthemiddle.Ifaplantislocatedinorneartheload,itmighthavenopower.Itwillbedirectaccesstosecondarytransmissionanddistributionsystem.Secondarytransmissionsystemvoltagegradetransmissionanddistributionsystembetweenvoltagelevel.Somesystemsonlysinglesecondtransmissionvoltage,butusuallymorethanone.Distributionsystemispartofthepowersystemanditsretailservicetousers,commercialusersandresidentsofsomesmallindustrialusers.Itistomaintainandinthecorrectvoltagepowertousersresponsible.Inmostofthesystem,Distributionsystemaccountsfor35%ofthetotalinvestmentsystemPresidentto45%,andtotallossofsystemofthehalf.

Morethan220kvvoltageareusuallyreferredtoasUltrahighpressure,over800kvcalledhighpressure,ultrahighvoltageandhighpressurehaveimportantadvantages,Forexample,eachroutehighcapacity,reducethepowerneededforthenumberoftransmission.Inashighvoltagetotransmissioninordertosaveaconductormaterialseemdesirable,however,mustbeawarethathighvoltagetransmissioncanleadtotransformer,switchequipmentandotherinstrumentsofspendingincreases,so,forthevoltagetransmissiontohavecertainrestriction,allowsittospecificcircumstancesineconomicuse.Althoughatpresent,powertransmissionmostisthroughtheexchangeofHVDCtransmission,andthegrowinginterestin,mercuryarcrectifierandbrakeflowpipeintotheacpowergenerationanddistributionthatchangeforthehighvoltagedctransmissionpossible.

Comparedwiththehigh-voltagedchigh-voltageactransmissionhasthefollowingsomeadvantages:

（1）thecommunicationwithhighenergy;

（2）substationofsimplemaintenanceandcommunicationcostislow;（3）acvoltagecaneasilyandeffectivelyraiseorlower,itmakesthepowertransmissionandhighpressureWithsafetyvoltagedistribution

HVDCtransmissionandhigh-voltageactransmissionhasthefollowingadvantages:

（1）itonlyneedtwophaseconductorsandactransmissiontothree-phaseconductors;

（2）inthedctransmissionimpedance,noRongKang,phaseshiftandimpactovervoltage;（3）duetothesameloadimpedance,nodcvoltage,andtransferofthetransmissionlinevoltagedroplesscommunicationlines,andforthisreasondctransmissionlinevoltageregulatorhasbetterproperties;（4）indcsystemwithoutskineffect.Therefore,theentiresectionofrouteconductorsareusing;（5）forthesamework,dcvoltagepotentialstressthaninsulation.ThereforedcWireneedlessinsulation;（6）dctransmissionlineloss,coronatolittleinterferencelinesofcommunication;（7）HVDCtransmissionwithoutlossofdielectric,especiallyincabletransmission;（8）indcsystemwithoutstabilityandsynchronizationoftrouble.

Atransmissionandthesecondtransmissionlinesterminatedinsubstationordistributionsubstations,thesubstationanddistributionsubstations,theequipmentincludingpowerandinstrumenttransformerandlightningarrester,withcircuitbreaker,isolatingswitch,capacitorset,busandasubstationcontrolequipment,withrelaysforthecontrolroomoftheequipment.Someoftheequipmentmayincludemoretransformersubstationsandsomeless,dependingontheirroleintheoperation.Someofthesubstationismanualandotherisautomatic.Powerdistributionsystemthroughthedistributionsubstations.Someofthembymanylargecapacitytransformerfeeders,largeareatootherminorpowertransformercapacity,onlyanearloadcontrol,sometimesonlyadoubly-fedwirefeeders（singlesinglevariablesubstation）

Nowforeconomicconcerns,three-phasethree-wiretypecommunicationnetworkiswidelyused,however,thepowerdistribution,fourlinesusingthree-phaseacnetworks.

Coal-firedpowermeansofmainpowergeneratingdrivegenerators,ifcoalenergyisusedtoproduceispushingtheimpeller,theng