寸金学院

isanelectricalpropertyoftheatomicparticlesofwhichmatterconsists,measuredin

coulombs.电荷是构成物质的原子电气属性，其量纲为库伦。

nceofequalnumbersofprotonsandelectronsleavesanatomneutrallycharged.

质子和电子数量相同使得原子呈电中性。

tageUabbetweentwopointsaandbinanelectriccircuitistheenergy（orwork）

neededtomoveaunitchargefromatob.

电路中a，b两点间电压Uab等于从a到b移动单位电荷所需能量（或所需做的功）。

.1-6(b)thebatteryisabsorbing24W,aswouldthecawhenitisbeingcharged.

图1-6中，电池就像充电情况，吸收功率24W。

ldbenotedthatanidealvoltagesource（dependentorindependent）willproduceany

currentrequiredtoensurethatidealvoltageisasstated,whereasanidealcurrentsourcewill

producethenecessaryvoltagetoensurethestatedcurrentflow.

应该注意：一个理想电压源（独立或受控）可向电路提供任意电流以保证其端电压为规定

值，而电流源可向电路提供任意电压以保证其规定电流。

alysisisnotquiteasgeneralasnodalanalysisbecauitisonlyapplicabletocircuitthat

isplanar.由于网孔分析法仅适用于平面电路，故网孔分析法不像节点分析法那样通用。

formationmightinvolvespeechandmusic,asinradiobroadcasting,aphysicalquantity

suchasthetemperatureoftheairinaroom,ornumericaldata,suchastherecordofstock

markettransactions.

这种信息或许像无线广播的演讲和音乐，或许是像室内温度的物理量，或许像股市交易记

录的数字数据。

alsignalisonethatcantakeonvalueswithin

gnalsareudtoreprentON-OFForYES-NOinformation.

另一种信号是数字信号。数字信号是在两个离散的范围内能够呈现一定数字的信号。这两

种信号常以表示开-关或是-不是信息。

binaryreprentationoftheamplitudetochangebyonebit,ananalogamplitudemust

changeby6.25percent.

二进制表示量改变一位，对应的模拟量大小就一定改变了6.25%。

tchesfeedaresistivesummingnetworkwhichconvertachbitintoitsweighted

currentvalueandsumsthemforatotalcurrent.

通过开关供给一个电阻性的加法电路，加法电路把每一位转变为对应的加权负载电流值并

求出总电流。

cticalswitchingdeviceshavelimitedcapabilitiesofrateofvoltagetransitionandtherate

onabrupttransitionratesgiveritopowerlossintheswitching

devices.

实际开关装置限制了电压变换速率和电流换向速率。非突变引起了开关装置的功率损失。

12Thecapacitorisassumedtobelargesothatthevoltagethroughitinsteadystateisnearly

thatinitiallytheswitchison,hence,thecurrentthroughtheswitchisIs.

ThecapacitorvoltageisUo,thevoltageacrosstheswitchiszeroandthediodeV1isrever

biad.

假设电容器很大，致使在稳态状况下其两端的电压接近为常数Uo。假设开关开始处于闭

合状态，则通过开关的电流为Is。电容器的电压为Uo，开关两端的电压为零，二极管V1

反向偏置。

vertsueffectivefilteringonboththeinputandtheoutputtoreducetheAC

componentsfromgoingoutsidetheconverters.

所有的滤波器均对输入和输出采用有效的滤波，以减少从变换器输出的交流成分。

nentapplicationoftheBuckconverterisaDCregulatedpowersupplyinwhichthe

outputvoltageisregulatedagainstthevariationsintheloadresistanceandtheinputvoltages.

降压式变换器的一个著名应用是用于直流可调电源，调整其输出电压以补偿负荷电阻和输

入电压的变化。

ticalmachinesthisrotatingmagneticfieldisachievedbyacombinationofaspace

displacementofthewindingsandatime-phadisplacementoftheexcitingvoltage.

在实际的电机中，旋转磁场是通过空间上交替布置是绕组和时间相位上相互交替的励磁电

压来实现的。

oilareconstructedfromrectangularwire,whichisbentintoshapearoundformsand

lisformedtothepropersizesothatthecompletecoilcanbeinrtedinto

thestatorslotsatthetimethestatoriswound.

这些线圈采用矩形截面的导线构成，将它们弯曲成型后缠上绝缘带。在制作定子绕组时，

线圈被做成适当的尺寸，以便将整个线圈放置入定子槽内。

eofconstruction

consistsofasimplerectangularlaminatedpieceofsteelwiththetransformerwindingswrapped

aroundtwosidesoftherectangle.

电力变压器的铁芯分为两类。一类是由变压器绕组缠绕在一个简单的矩形钢片叠成的铁芯

两边而构成。

ondtypeofspecialtransformerisadevicedesignedtoprovideacondarycurrent

muchsmallerthanbutdirectlyproportionaltoitsprimarycurrent.

第二类特种变压器是专门用以提供比一次测电流小得多却正比于一次电流的二次电流。

netizationcurrentimisacurrentproportional(intheunsaturatedregion)tothevoltage

appliedtothecore,andlaggingtheappliedvoltageby90*,soitcanbemodeledbyareactance

Xmconnectedacrosstheprimaryvoltagesource.

磁化电流im正比于作用于铁芯的电压，并滞后该电压90*，因此可以采用并联于初级电压

源的电抗Xm来建模。

19．Mostpeoplecanformulateamentalpictureofacomputer,butcomputerdosomanythings

andcomeinsuchavarietyofshapesandsizesthatitmightemdifficulttodistilltheir

commoncharacteristicsintoanall-purpodefinition.

大多数人都能描绘一台计算机，但由于计算机能做许多事情，有许多形状和规格，以致人

们难以提取其共同特征形成通用的定义。

iesofinstructionsthattellacomputerhowtocarryoutprocessingtasksisreferredto

asacomputerprogram,orsimplya“program”.

告诉计算机如何执行处理任务的一系列指令被称为计算机程序，简称为程序。

powersystemsareusuallylarge-scale,geographicallydistributed,andwithhundredsto

thousandsofgeneratorsoperatinginparallelandsynchronously.

现代电力系统通常是规模大，地域分布广，具有成百上千并列同步运行的发电机组。

erudtodaymaynotbeavailableinthefuturewhenitsumightbemore

advantageous.

今天用掉的水可能在未来更有用时不能再用得到。

ral,costs,curity,andemissionsareallareasofconcerninpowerplantoperation,and

inpracticethesystemisoperatedtoeffectacompromibetweenthefrequentlyconflicting

requirements.

一般来讲，成本、安全和排放问题都是电厂运行需要考虑的方面，通常的做法是系统的运

行需在各种矛盾的要求之间折中考虑。

ncyofspeedofmotordrivesisparticularlyimportantforsatisfactoryperformanceofall

theauxiliarydrivesassociatedwiththefuel,thefeed-waterandthecombustionairsupply

systems.电动机转速的恒定对燃料、给水和送风等有关的辅机设备的良好运行是特别重

要的。

tectiverelayisansingdevice,whichnsthefault,determinesitslocationandthen

ndcommandtothepropercircuitbreakerbyclosingitstripcoil.

保护继电器是一个感知装置，它感知故障、确定故障位置，并且通过闭合相应断路器的跳

闸线圈来发出跳闸命令。

ensiveuofelectricclocksandtheuoffrequencyforothertimingpurporequire

accuratemaint

conquence,itisnecessarytoregulatenotonlythefrequencyitlfbutalsoitsintegral.

电钟和其他使用频率定时的设备的广泛应用要求维持准确的同步时间，该时间正比于频率

的积分。所以，不仅需要调整频率自身而且需要调整它的积分。

26．Inaninterconnectedpowersystem,theprimaryobjectivesofAGCaretoregulatefrequencyto

thespecifiednominalvalueandtomaintaintheinterchangepowerbetweencontrolareasat

thescheduledvaluesbyadjustingtheoutputofthelectedgenerators.

在互联电力系统中，AGC的主要目标是通过调节指定发电机的输出将系统频率调整到额定

值，并且将区域间的功率交换维持在所要求的水平。

onouscondenrsandSVCsprovideactivecompensation,thereactivepower

absorbed/suppliedbythemisautomaticallyadjustedsoastomaintainvoltagesofthebusto

whichtheyareconnected.

同步调相机和SVCs提供有源补偿，它们吸收或发出的无功功率可以自动调整以维持它们所

连母线的电压水平。

r,ifduetoanyreason,sayafault,thereisanabnormality,itisnecessarythatthere

shouldbeadevicewhichnstheabnormalconditionsandifso,theelementor

componentwheresuchanabnormalityhastakenplaceisremoved,dfromtherestof

thesystemassoonaspossible.

然而，由于任何原因，比如说故障，出现非正常运行状态，有必要采用一个装置来感知这种非

正常状态，然后这种出现非正常状态的元件可以被切除，也就是说，尽可能快地将该元件与系

统其他部分相隔离。

电流current

电压voltage

电荷charge

电路circuit

电动势electromotiveforce

积分integrate

电位差potentialdifference

参考方向referencedirection

瞬时功率instantaneouspower

有源的active

有源元件activeelement

电阻；电阻器risistor

电容器capacitor

电感器inductor

理想独立源idealindependentsource

发电机gennerator

晶体管；半导体管transistor

放大器amplifier

阻力；阻尼resistance

伏安特性voltage-currentcharacterristic

短路shortcircuit

开路opencircuit

节点分析nodalanalysis

网孔分析meshanalysis

联立（方程）的simultaneous

交流AC=alternatingcurrent

直流DC=directcurrent

数字的digital

恒温器thermostat

模数转换A/D=Analog-to-Digital

数模转换D/A=Digital-to-Analog

传感器transducer

分压器voltagedivital

半导体miconductor

电力电子powerelectronic

损耗loss

变压器，变换器transformer

介质，绝缘材料dielectric

整流器rectifier

滤波，过滤filter

匝数比turnratio

感应电机inductionmachaine

磁场magneticfield

励磁电压excitingvoltage

一次绕组，原绕组primarywinding

二次绕组，副绕组condarywinding

三次绕组tertiarywinding

漏磁通leakageflux

自感应lf-inductance

微型计算机mirocomputer

台式计算机desktopcomputer

笔记本电脑notebookcomputer

调制解调器modem

外围设备peripheraldevice

操作系统operatingsystem

并联地inparallel

变电所，变电站substation

水力发电hydro-generation

电力机组，热力单位thermalunit

无功功率reactivepower

有功功率activepower

电力系统保护powersystemprotection

继电器relay

断路器circuitbreaker

热继电器thermalrelay

lationisbetweenpowerandenergy?

W=∫Pdt

ementisanidealindependentsource?

Anidealindependentsourceisanactiveelementthatprovidesaspecifiedvoltage

orcurrentthatiscompletelyindependentofothercircuitvariables.

eresistancevalueofalinearresistorvarywiththecurrentthroughit?

Yes,itdoes.

ledoesatransducerplayinasignal-processingsystem?

Atransducerconvertsaphysicalormechanicalvariabletoanequivalentvoltageor

currentsignalasaninputsignaloftheprocessingsystem.

estheoutputformofasystemdependon?

Theoutputformofasystemdependsontheutobemadeoftheinformation

containedintheinputsignals.

ossarepowerlossinthepowerelectronicconverterscompridof?

Thepowerlossinthepowerelectronicconvertersarecompridofthe

switchinglossandtheparasiticloss.

ethemajorlossitemstobeconsideredintheconstructionofsucha

equivalentcircuitmodel？

Themajorlossitemstobeconsideredintheconstructionofsuchaequivalent

circuitmodelarecopperloss,eddycurrentloss,hysteresislossandleakage

flux.

indscancomputersbecategorizedas?

Computerscanbecategorizedaspersonalcomputers,handheldcomputers,

workstations,mainframes,supercomputersandrvers.

ymeaningsdoestheterm“rver”have?

efertocomputerhardwaretoaspecifictypeofsoftware,or

toacombinationofhardwareandsoftware.

mponentsisamodernpowersystemcompridof?

Amodernpowersystemisusuallycompridoftransmissionlines,transformers

andswitchingdevices,etc.

选择

nventionaltotakethecurrentflowasthemovementof___ve

charges

iccurrentisthetimerateofcharge,measuredin___.s

rgyrequiredtomoveaunitchargethroughanelementis___.e

s(+)andminus(-)signsinanelectricdiagramareudtodefine___.

epolarity

ingtothepassivesignconvention,ifthepowerhasaplussign,power

is___ed

pendentvoltagesourceisa___,whichmaintainsaspecifiedvoltage

-terminalelement

orsare___e

ldependentsourceisan___elementinwhichthesourcequantityis

re___

Foravoltagesource,itsterminalvoltageisknownbutits___mustbedetermentby

t

cuitelementudtomodelthecurrent-resistingbehaviorofamaterialis___

isfor

’sLawstatethatthevoltageacrossaresistoris___thecurrentflowingthrough

lyproportionalto

torwhoresistancesvarywithitscurrentisknownas___near

resistor

4.___circuit

istanceoftheheateris___

C.12Ω

nalysisbadonasystematicapplicationof___,andsatisfies

automatically___.

,KVL

2.___

analysis

rcuitcontainingNnodesandMbranches,therewill

be___independentnodevoltages.B.N-1

entialatreferencenodeordatumnodeis___innodalanalysis.

alysisapplies___tofindunknowncurrentswhichare___currents

,mesh

tageproducedbyathermocouplepairis___og

-OFFinformationcanbereprentedby___al

ethatcanconverananalogsignaltothecorrespondingdigitalfromis

called___forshort.A.A/D

rmocouplepairconvertstemperaturedifferencetoa___.

e

/Aisadevicethatcanconvertadigitalsignaltotheequivalent___.

form

cessofquantizingthecontinuousvaluesintoabinaryscaleis

called___.-to-digitalconversion

2.___isadevicethatproducesavoltageoracurrentproportionaltotheactual

raturetransducer

cisionandthespeedofanADCareesntially___.atoble

cisionofADCisdeterminedby___.berofbinarybits

.2-4theamplifierperforms___

tchinglossarecompridoftheon-statelosd,___andthelossinthe

-stateloss

icalpowertransistorsintheon-statehave___.B.0.7V

ertransistors,alectricalswitches,withstand___voltageintheoff-state.

ver

eofvoltagetransitionandtherateofcurrentsteeringcanproduce___inthe

oss

-DCconverterconverts___inputto___current,direct

current

kisa___tstep-up

controlthatus___tocontroltheoutputvoltageismorepopular.

idth

nofswitch-modelinearamplifierisdeterminedby___voltage,andthe

outputvoltageisalinearfunctionof___.utdcsource,thecontrolvoltage.

mbisthedirectionof__inFleming’ativemotion

ofconductor

ctionmotorsthespeedoftheroatingrotor___thespeedoftherotating

magneticfield.

eaches

espeedoftherotoriszero,theslipofinductionmachineis___.C.1.0

-woundcoilsarewidelyudfor___C

formerisadevicethatcanconverteroneacvoltagetoantheracvoltage

throughtheactionof___.ticfield

marywindingisconnerctedto___.ersource

econstructionconsistingofathree-leggedlaminatedcorewiththewinding

wrappedaroundthecentrelegiscalled___.orm

nsformerthattakesthedistributionvoltageandstepsitdowntothefinal

voltageatwhichthepowerisactuallyudiscalleda___.bution

transformer

lossare___lossintheprimaryandcondarywindingsofthe

ive

terworksautomaticallyaccordingto___.sofstored

instructions.

ardoramouis___t

puternetworkforauniversityisusuallydescribedas___.area

network

terthatrequests-datafromarveriscalledas___.

iskisreferredtoas___ge

rplants___converttheprimaryenergytomechanicalenergy,and

___oves,synchronous

generators.

eratorvoltageareusuallysteppeduptothetransmissionvoltagelevelby

___.-uptransformers

ntialandcommercialcustomersaresuppliedbythecondarydistribution

feedersat___.A.120/240V

,thevoltageofthetransmissionsystemaretypically___.C.230KVandabove

ectiveoftheoptimaleconomicoperationofpowersystemsis___.

minimizethetotalproductioncost.

quencyofapowersystemisdeterminedmainlyby______.

powergenerationandconsumption

tagelevelsattheterminalsofgeneratorsarecontrolledmainlyby___.

ticvoltageregulators

esystemfrequencyischangedawayfromtherating,___muberegulated.

power

tionofthegenerator’sspeedgovernorcanchangeits___

power

tectiverelaydisconnectsfaultedelementsinapowersystemby___.

ngthepropercircuitbreakers.

etripcoilofaciucuitbreakerixcitedbyaprotectiverelay,thecircuit

breakerits___.

edoff

tectionschemeconsistsbasicallyof___.ments

___ofaprotectiverelayisthatitmustoperatecorrectlyifthereisafaultand

ility

tectiveschemethatnszeroquencecurrentandoperatesas

necessaryiscalledas___.quenceprotection