轮机英语77课件

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MarineElectricalSystemandAutomatizationLesson26Marine

ElectricityDistributionSystem第26课船用电力分配系统LearningObjectives:1.Graspsomeusefulwordsandexpressionsinthewholetext.2.Afterstudyingthelesson,heorshewillhaveabetterunderstandingofMarine

ElectricityDistributionSystem.3

4part1

NewWordsandExpressions5part2

TextAnalysisL26ElectricityDistributionThecontrolanddistributionoftheelectricalenergygeneratedbygeneratorsareeffectedbypowerdistributionequipment,i.e.switchboards.#发电机产生的电能的控制和分配受配电设备(即配电盘)的影响。L26ElectricityDistributionSwitchboardsareeither(a)Mainswitchboards,(b)Emergencyswitchboards,(c)Sectionboards(orsub-boards),or(d)Distributionboards.#配电盘可以是(a)主配电盘、(b)应急配电盘、(c)区域配电盘(或子配电盘)或(d)分配电盘。8

Introduction(Backgroundknowledge)

L26ElectricityDistributionAmainswitchboardconsistsofthegenerator

controlpanel,theloadpanelandthepaneloftheparalleloperationofthegenerator.#主配电盘由发电机控制屏、负荷屏和发电机并车屏组成。

Introduction(Backgroundknowledge)

Introduction(Backgroundknowledge)

Introduction(Backgroundknowledge)

L26ElectricityDistributionItsmainfunctionisto(1)switchonoroffthecurrentcircuitaccordingtotherequirement(manuallyorautomatically);其主要功能是(1)根据需要(手动或自动)接通或断开电流回路；L26ElectricityDistribution(2)maketheprotectiondeviceenergizetodisconnecttheelectricalequipmentwiththecircuit,givingthealarmsignalwhenthereissomethingwrongwiththeelectricalpowersupplysystem;使保护装置通电，以断开电气设备与电路的连接，当供电系统出现故障时发出报警信号；L26ElectricityDistribution(3)measureorindicateeveryelectricalparameterssuchasvoltage,current,watt,powerfactoretc.duringtheoperation;测量或指示运行中的电压、电流、瓦特、功率因数等各项电气参数；L26ElectricityDistribution(4)adjustthedistributionofthepowerofthegeneratorinparalleloperationorthevoltage,frequencyofthepowerstation;调整并联运行发电机的功率分配或电站的电压、频率；L26ElectricityDistribution(5)indicatethesignaloftheconditionofthecurrentcircuit,theconditionofthebreakersandtheerrorfromthenormalworkingcondition.指示电流回路状态信号、断路器状态和正常工作状态的偏差。L26ElectricityDistributionThegeneratedsupplyisprovidedtoconductorsknownas“bus-bars”whicharelocatedbehindthemainswitchboard.#产生的电能提供给叫做“汇流排”的导体，它位于主配电盘的后面。L26ElectricityDistributionThesupplythenpassesthroughcircuitbreakerstoauxiliariesdirectlyortosectionordistributionboards.#电能则通过断路器直接通向辅助设备，或者其它区域配电盘或分配电盘。L26ElectricityDistributionAcircuitbreakerisanisolatingswitch.#断路器其实就是一个独立的开关。L26ElectricityDistributionAsectionboardisagroupingofelectricalservicesfedfromthemainboard.#区域配电盘是由主配电盘供电的一组电气设施。L26ElectricityDistributionAdistributionboardfeedsminorsuppliessuchaslightingandmayitselfbefedfromthemainboardorasectionboard.#分配电盘供给小的电力，比如照明，并且可能自身由主配电盘或区域板供电。L26ElectricityDistributionAnACdistributionsystemisprovidedfromthemainswitchboardwhichisitselfsuppliedbythealternators.#交流电配电系统的电是由主电板分配的，交流发电机直接向主配电盘供电。L26ElectricityDistributionThevoltageattheswitchboardisusually415butonsomelargeinstallationsitmaybeashighas3,300.#主配电盘上的电压一般为415伏，但在一些大型的设备上，电压有可能达到3300伏。L26ElectricityDistributionPowerissuppliedthroughcircuitbreakerstolargerauxiliariesatthehighvoltage.#它通常在高压状态下，通过断路器向大型辅助设置上输出功率。L26ElectricityDistributionSmallerequipmentmaybesuppliedviafusesorminiaturecircuitbreakers.#而小型的设备则可以用熔断器(保险丝)或者微型断路器。L26ElectricityDistributionLowervoltagesuppliesused,forinstance,forlightingat220volts,aresuppliedbystepdowntransformersinthedistributionnetwork.#例如，用于220伏照明的低压供电，可以在分电网中由降压变压器来供电。L26ElectricityDistributionThedistributionsystemwillbethreewireswithinsulatedorearthedneutral.#配电系统是三线(相)绝缘或者中线接地。L26ElectricityDistributionTheinsulatedearthhaslargelybeenfavoredbutearthedneutralsystemshaveoccasionallybeeninstalled.#大多数使用的是三线绝缘的配电系统，中心接地的系统有时也会使用。L26ElectricityDistributionTheinsulatedearthsystemcansufferfromsurgesofhighvoltageasaresultofswitchingorsystemfaultswhichcoulddamagemachinery.#由于断开与闭合或者可能损坏机器的系统故障，三相绝缘系统可能遭受高压电涌。L26ElectricityDistributionUseoftheearthedsystemcouldresultinthelossofanessentialservicesuchasthesteeringgearasaresultofanearthfault.#接地系统的使用可能导致一项重要的用途，比如舵机，由于接地故障而丧失。L26ElectricityDistributionAnearthfaultontheinsulatedsystemwouldnothoweverbreakthesupplyandwouldbedetectedintheearthlampdisplay.#然而，绝缘系统中的一个接地故障不会导致供电中断，同时能够在接地指示灯上显示出来。L26ElectricityDistributionInsulatedsystemshavethereforebeengivenpreferencesinceearthfaultsareacommonoccurrenceonshipsandalossofsupplyinsuchsituationscannotbeaccepted.#由于接地故障在船上普遍发生，并且在这些情况下供电中断不能被接受，因此，(三相)绝缘系统得以青睐。L26ElectricityDistributionInthedistributionsystemtherewillbecircuitbreakersandfuses.#配电系统中会有断路器和保险丝。L26ElectricityDistributionEquipmentforACsystemsishoweversmallerandlighterbecauseofthehighervoltageandthereforelowercurrents.#然而，交流系统中的电器设备较小和较轻，因为其较高的电压、较低电流。L26ElectricityDistributionMiniaturecircuitbreakersareusedforcurrentsuptoabout100A

andactasafuseandacircuitbreaker.#微型断路器用于电流高达100A，起到保险丝和断路器的作用。L26ElectricityDistributionThedevicewillopenonoverloadandalsointheeventofashortcircuit.#这种设备会在过载和发生短路的情况下自动断开。L26ElectricityDistributionUnlikeafuse,thecircuitcanbequicklyremadebysimplyclosingtheswitch.#不同于熔断器(保险丝)，电路还能够通过开关简单的闭合来达到电路迅速的恢复。L26ElectricityDistributionAlargeversionofthisdeviceisknownasthemouldedcasecircuitbreakerandcanhandlecurrentsinexcessof1,000A.#这种形式的设备被称为塑壳式断路器，并且它能够处理超过1000A的电流。L26ElectricityDistributionPreferentialtrippingandearthfaultindicationwillalso

beapartoftheACdistributionsystem.#优先卸载和接地故障指示也是交流配电系统的一部分。L26ElectricityDistributionPreferentialtrippingisameansofretainingessentialelectricalsupplies.#优先卸载是保持重要电力供应的一种方法。L26ElectricityDistributionIntheeventthatageneratorcannotsupplyalltheloadthennon-essentialloadsaredisconnectedbypreferentialtrips.如果发电机不能向所有的负载供电，那么不重要的负载就被优先卸载所断开。L26ElectricityDistributionTheintentionistoreducethegeneratorloadwhileensuringessentialequipmentsuchassteeringgear,navigationlights;etc.retainsitselectricalsupply.#这样的目的就是减少发电机所承受的负载来保证重要的设备，比如舵机、航行灯等等，保持其电力供应。L26ElectricityDistributionEarthfaultsareusuallydetectedbytheuseof

earthindicatinglamps.#可以使用接地故障指示灯来检测接地故障。L26ElectricityDistributionTwolampsareused,eachratedforthefullsystemvoltage,butconnectedinseriesacrossthesystemwiththemidpointearthed.使用两盏灯，每盏灯的额定电压为系统全电压，但在系统中串联连接，中点接地。L26ElectricityDistributionIfthesystemiscorrectlyinsulatedthenbothlampswillglowathalfbrilliance.Thelampsareplacedclosetogethertoenableacomparisontobemade.#如果系统完全绝缘，那么两盏灯会(因为各得一半电压而)处于一半亮度。两盏灯要放在一起，以便能够做出对比。L26ElectricityDistributionAdirectearthinonepolewillshortcircuititslamp,causingtheothertoshinelightly.Aslightinsulationbreakdownwouldproduceadifferenceinbulbbrightnessbetweenthetwo.#任何一个直接接地点都会将其中的一个灯短路，从而会使另外的一个灯变得更亮。轻微的绝缘故障会使两个灯泡的亮度产生不同。L26ElectricityDistributionWhereanearthfaultisdetectedthecircuitbreakersforeachseparatecircuitmustbeopenedinturnuntilthefaultlocationisdiscovered.#在检测到接地故障的地方，每个独立电路的断路器必须依次断开，直到发现故障位置。L26ElectricityDistributionTheparticularsectionordistributionboxwouldthenhavetohaveitscircuitsinvestigatedonebyonetolocatethefaultandenableitscorrection.#特定的区域配电箱或者分配电箱则必须要一个接一个的调查它们的电路，然后确定故障并使它们恢复正常。part3

Exercise&ExaminationAmolded-casecircuitbreakerprovidesprotectionagainstshortcircuitsbyusinga/an_____.A.electromagnetB.shadingcoilC.arcquencherD.burnawaystrip