电工证模拟考试试题

电工证模拟考试试题(Electricalcertificatesimulation

examinationquestions)

Electricalcertificatesimulationexaminationquestions

2014-2-2616:03|Publisher:admin|view:18525review:0

First,themultiple-choicequestion

1,tworatedvoltageofthesameresistor,seriesconnectedto

thecircuit,theresistanceisgreaterresistance(A).

A,calorificvalueisbigger,B,calorificquantityislesser,

C,withoutapparentdifference

2,themultimeterswitchisrealized(A).

A,variousmeasuringtypesandrangesofswitches,B,

multimetercurrentswitchon

AmeasuringswitchforCtoswitchonthemeasuredobject

3,insulationrodshouldbenormal(B).

A,placeasmoothB,sothattheydonottouchthegroundand

walls,inordertopreventmoisture,deformation,C,placedin

thecorner

4.Thetestperiodofinsulatingglovesis(B).

A,onceayear,B,onceeverysixmonths,C,onceeveryfive

months

5,thetestperiodofinsulatingbootsis(B).

A,onceayear,B,onceeverysixmonths,C,onceeverythree

months

6.Whenmovingonduty,removeorcrossthebarrier(C).

A,theremustbealeaderinthepresenceofB,theremustbe

apoweroutage

C,theremustbeaguardianpresent

7.Thedutyofficervisitsthehighvoltageequipment(A).

A,usuallycarriedoutbytwopeople,B,dutyofficercando

otherwork

C,ifyoufindproblems,youcanalwayshandle

8,aftertheoperationofthetickethasbeenexecuted,itmust

be(B).

A,savetohandoverclassB,keepforthreemonths,C,longtime

preservation

9,toacceptthereverseoperationcommand(A).

A,theguardianandoperatorshallbepresent,andshallbe

acceptedbytheguardian

B,aslongastheguardianispresent,theoperatorcanalso

accept

Ccanbeacceptedbysubstation(station)

10.ThepositivephasepaintoftheDCbusisspecifiedas(C).

A,blue,B,whiteC,ocher

11.Thegroundinglineshallbepaintedas(A).

A,black,B,purple,C,white

12、themaximumallowabletemperatureoftheequipmentjoint

andwireclipis(A).

A,85,B,90,C,95

13、themaximumallowabletemperatureoftheouterskinof

thecurrenttransformeris(B).

A,60,B,75,C,80

14,thepowercableshallnotoverloadoperation,inthecase

ofaccidents,10KVbelowthecableonlyallowedcontinuous(C)

operation.

A,1hoverload,35%B,1.5hoverload,20%C,2hoverload15%

15,thepowertransformeroil(A)role.

A,insulationandarcextinguishing,B,insulationandrust

prevention,C,insulationandheatdissipation

16.Therelayprotectiondeviceiscomposedof(B).

A,twocircuit,eachcomponentB,allkindsofrelays

C,includingvariousrelaysandinstrumentcircuits

17,afterthesignalrelayaction(C).

A,relayitself,cardorlightindication

B,pleaseconnectthelightandacousticcircuitimmediately

Cshouldbeonesideofthecarditself,whilethecontactclosed

toswitchonothersignals

18,thelinerelayprotectiondevicecanquicklyremovethe

faultpartwhenthelinefails,and(B).

A,automaticreclosing,onceB,sendoutsignal

Cwillcontinuetoruntheintactpart

19,theinstallationofgroundwireshouldbe(B).

A,firstinstallthephaseB,firstinstallthegroundterminal,

andtheninstallbothsides

C,startwithwireends

20,wearinginsulatingglovesforoperation,

Coatcuffs(A)shouldbeworn.

A,putininsulatinggloves,B,rollupC,setoutsidethegloves

21,alineswitchpoweroutageinspection,thelinesidebypass

operation,thenshouldbeontheswitchhandlehanging(C)

signs.

A,inthiswork,B,prohibitclosingtheC,prohibitclimbing,

highvoltagedangerous

Two,fillintheblanks(1pointspersmall,atotalof***)

1,thefunctionofaloadistoconvert(electricalenergy)into

(otherformsofenergy).

2ohm，slawtellsusthatthroughtheresistanceelementatboth

ends(current)isproportionaltothevoltagebetweenthetwo

ends,andwhenthevoltageisfixed,itisinversely

proportionalto(resistance).

3,thecurrentthroughtheresistance,theresistancewillheat,

theelectricenergyintoheatenergy,whichis(thethermal

effectofelectricity).

4,theadvantagesofalternatingcurrentaremany,inwhichthe

transmissionvoltagewillbeincreased,inordertoreducethe

lossoftheline;whenthepowerisusedtoreducethevoltage

toreduce(usevoltage).

5capacitorchargingistoprovideelectricenergy(electric

fieldenergy)storage;capacitordischargeisto(electric

fieldenergy)release.

6,inallkindsofelectricalaccidents,(short-circuit)

occupiesaparticularlyprominentposition.

7,ourcountrystipulated(42),(36),(24),(12),(6)asthe

safetyvoltage.Underwetconditions,use(12)belowvolts.

8,10000Hzhighfrequencyalternatingcurrentperception

current,maleabout(1.5)MA,femaleabout(0.6)MA;average

outofcurrent,maleabout(16)MA,femaleabout(10.5)ma.

9,generallyspeaking,theelectricshockformhas(contact

electricshock),(inductionelectricshock)and(stepvoltage,

electricshock)threekinds.

10,green,middle-agedandnonelectricalshockaccidentalot,

Thisismainlyduetothefactthatthesepeoplearetheprimary

operators,(therelativelackofelectricalsafetyknowledge),

and(inadequatesafetymeasures).

Three,determinethetitle(everydayatotalof2points**

points)

1,inordertopreventelectricshockcanbeavoided,onlygood

electricalsafetymanagementworkcanbe.(X)

2,electricalsafetyinspectionismainlytocheckwhetherthe

lineleakageandwhetheranyonegetsanelectricshock.(X)

3,highvoltageequipmentswitchingoperation,mustfillinthe

operationticket,shouldbeoperatedbytwopeople.(V)

4、highvoltagetestmustbeinsulatedgloves.(V)

5.Liveworkingisnotlimitedbyweatherconditions.(X)

6,protectionofgrounding,protection,zeroconnection,

strengtheninginsulation,belongingtothepreventionof

indirectelectricshocksafetymeasures(V)

7.Whenmeasuringtheinsulationresistanceofthelinetothe

ground,theGterminalshallbegroundedandtheLterminal

shallbeconnectedwiththewire.(V)

8,severallinesofthesametowershallobtaintherelevant

departmentstothepowerlineinthecommunicationlinetothe

top,andhighvoltagelineinlowvoltageline.(V)

9、protectiveearthingisapplicabletoungroundedpowergrid

(V)

10、intheprotectivezeroconnectionsystem,theprotection

deviceisonlyforthepurposeofensuringthesafetyofthe

person.(X)

11,theuseofcurrenttransformerscanallowtwosideopen

circuit.(X)

12.Switchonthehighvoltagecircuitbreakerwhenswitching

on,andthendividetheswitchfirst.(X)

13,0.1instrumentishigherthan0.2meterprecision(V)

The14and800voltlinesarehighvoltagelines.(X)

15,knifeswitchwitharubbercovercandirectlycontrolthe

motor12kw.(X)

Four,questionsandanswers(commonscore)

1,underwhatcircumstances,electricalequipmentmaycause

spaceexplosion?.

Answer:equipmentshortcircuit,encounterlightningstroke,

insulationisdestroyed,allmaycausespaceexplosion.

2,inthefirescenehasnotpowercut,shouldtrytocutoff

thepowersupply,cutoffthepowersupply,shouldpayattention

towhat?

A:afterthefire,duetodamporsmoke,theinsulationcapacity

oftheequipmentisreduced,sotheuseofappropriate

insulationtoolsshouldbeusedtopreventelectricshock.

Theplaceofcuttingoffthepowersupplyshouldbeproper,and

thefirefightingwillbeavoidedaftercuttingoffthepower

supply.

Thecutwire,cutwireshouldbedifferentindifferentparts,

soastoavoidshortcircuit,aircutwire,cutpositionshould

choosesupportinthedirectionofthepowersupply,toprevent

thewirecutdownaftercausingashortcircuitorelectric

shockaccident.

Ifthereisaloadontheline,theloadshouldberemovedfirst,

thenthefirefightingpowersupplywillbecutoff.Intheopen

switchwhenpowersupplyiscutoff,usetheinsulatingrodor

thetipofgloves,topreventelectricshock.

3,transformerparalleloperationshouldhavethose

conditions?

Answer:transformerparalleloperationshouldhavethose

conditions?:

Equalratio

Wiringgroupthesame

Equalimpedancevoltage

Thecapacitydifferenceisnotmorethan3times

4.Whatarethetypesofrelaysincommonuse?

Answer:accordingtothedifferenceofthephysicalquantity

oftheresponsecomponent,therelaycanbedividedintotwo

kinds:theelectricityquantityandthenonelectricquantity.

Itbelongstothenonelectricgasrelay,thespeedrelay,the

temperaturerelayandsoon.

Therearemanykindsofreactivepower,whicharegenerally

dividedinto:

Accordingtotheprincipleofoperation,itcanbedividedinto

electromagnetic,induction,rectifierandtransistor.The

characteristicsofreactivepowerarecurrentrelayandvoltage

relay;

Itcanbedividedintoelectricrelay,timerelay,signalrelay

andsoonaccordingtothefunction.

5、Whataretheinspectionitemsofinductiontypecurrent

relay?

Answer:inductiontypecurrentrelayovercurrentrelay,which

includesfaultelementsensingelementandspeed,thecommonly

usedmodelsforGL-10andGL-20twoseries,intheinspection

andregularinspection,theinspectionitemsareasfollows:

1,theinternalandexternalinspection;mechanicalparts

inspection;third,theinitialcurrent,insulationtest;test;

5,actionandthereturnvalue,thespeedofpneumatic

componentsinspection;inspection;andtheactiontime

characteristictest;thecontactreliabilitytest.

6,howtocorrectlyusegroundshakingtable?

Answer:beforemeasuring,thefirsttwoprobewereinserted

intotheEelectrodeinthepotentialandcurrentprobePprobe

Cinastraightlineand20metersapart,PEandinsertedinto

C,thenusespecialwirerespectivelycorrespondingtoterminal

E,P,Conthereceivinginstrument.

Whenmeasuringthefirstpointerinstrumentonahorizontal

positiontocheckwhetherthegalvanometerreferstothecenter

line,orbyzeroadjuster,thepointeradjustmenttothecenter

line,thentheinstrument"letterratescaling"atthemaximum

multipleslowlyturnthecrankandrotatinggenerator,

,'measuringdial"thegalvanometerpointerbalance,whenthe

pointernearthecenterline,speedupthegeneratorcrankspeed

upto120rpm,andthenadjustthe,'measurementscale"inthe

centerofthepointerline,''measuringdial"readings

，zmultipliedbytherateofscalingmultiples,namelythe

measuredresistancevalue.

7.Whatexternalinspectionsshouldtherelaysbeconducted?

Answer:thefollowingexternalinspectionshouldbedonewhen

therelayischeckedorcheckedregularly:

Therelayshellshouldbeintact,andthebaseofthecover;

thecomponentsshouldnothavetraumaanddamage,andinstalled

bythefirmandneat;thescrew,terminalandconductivepart

connectingwirethecomponentsshouldnotopenweldingandbad

contactoxidationphenomenon,thescrewandtheterminalshould

havewashersandspringpad;thenonconductivepart,suchas

aspring,a1imitrod,mustbefixedwithscrewsanddurable

paintandseal.

8,whatisthetransformerinsulationabsorptionratio?

Answer:intherepairandmaintenanceoftransformer,need

insulationabsorptancemeasurementoftransformer,itisequal

to60secondsofthemeasuredvalueofinsulationresistance

ratioofR60/B15absorptionratiocanbeasteptojudge

whetherthehumidinsulationandinsulationresistancein15

secondsofthemeasuredvalue,dirtyordefective,therules

in10~30C,35~60kVwindingisnotlessthan1.2110^330kV

windingisnotlessthan1.3.

Whataretheinspectionitemsofthe9andDX-11signalrelays?

Answer:1,theinternalandexternalinspection;mechanical

partsinspection;third,fourth,DCinsulationtest;

resistancemeasurement;5,6,contactactionvaluetest;

reliabilitytest.

10,DX-11typesignalrelayactionvalue,returnvalue,howto

test?

Answer:testwiringandintermediaterelaysame,forcurrent

typerelay,itsactionvalueshouldberatedvalueof70~90%,

forvoltagetypesignalrelay,itsactionvalueshouldberated

valueof50"70%.

Thereturnvalueshallnotbelessthan5%oftheratedvalue,

Iftheactionvalueandthereturnvaluedonotmeetthe

requirements,thespringtensionorthedistancebetweenthe

armatureandtheironcorecanbeadjusted.

11.Whatistheselectivityofrelayprotectiondevices?

Answer:protectionbyselectiveprotectionschemeandsetting

calculationofthedecision,whenafaultoccurs,therelay

protectiondevicecanrapidlyandaccuratelyfaultequipment

removed,theharmcausedbythefaultandthepowerrangeis

reducedasfaraspossible,soastoensurethenormaloperation

ofequipmenttononfaultprotectiondevice,canmeettheabove

requirements,arecalledselective.

12,whataretheadvantagesofthequickactionoftherelay

protectiondevice?

Answer:1,quickaction,quicklyremovethefault,canreduce

theuserinreducingvoltageworkingtime,acceleratethe

processofnormaloperation,rapidrecovery;theremovalof

faults,theextentofthedamagecanreducetheelectrical

equipmentfailureaffected;therapidremovaloffault,fault,

canpreventtheexpansion.

13,whatarethecharacteristicsofcurrentquickbreaking

protection?

Answer:noquickbreakcannotprotectthelinelengthoftime

current,itcanonlybeapartoftheprotectivecircuit,system

operationmodechange,willaffectthescopeofprotection

current,inordertoensuretheselectiveaction,thestarting

currentmustbeaccordingtothemaximumoperatingmode(i.e.,

thecurrentthroughthelineoperationmodeforthelargest)

tothewholebutontheother,sotheoperationmodeofthe

protectionrangeisshortened,fortheminimumprotectionrange

shouldnotbelessthan15%ofthelengthoftransmissionline.

Inaddition,thelengthoftheprotectedlinealsoaffectsthe

characteristicsoffastbreakingprotection.Whenthelineis

longer,theprotectionrangeislarger,andtheoperationmode

ofthesystemislessaffected.Otherwise,thelineisshorter,

Theinfluenceisgreater,andthescopeofprotectionwillbe

shortenedtozero.

Howabouttheactionvalueandreturnvalueofthe14and

DS-110/120timerelays?

Answer:thevariableresistorvoltageisincreased,the

armatureinhalation,breakingtheimpactofaddingsurgerygate

voltage,thisvoltageandarmatureshouldsuck,namelyaction

voltagerelay,thenreducethevoltage,thehighestvoltage

makesthearmaturebackinforthereturnvoltage.

FortheDCtimerelay,voltageshouldnotexceed65%oftherated

voltage,thereturnvoltageshouldnotbelessthantherated

voltageforAC5%,timerelay,voltageshouldnotexceed85%

oftheratedvoltage,ifthevoltageistoohigh,itshould

adjustthespring.

15.Whataretherequirementsforthebreakercontrolcircuit?

Answer:thecontrolcircuitbreaker,circuitbreakertype

accordingtodifferentrequirements,typesofoperation

mechanismandoperationofthedifference,butbasicallythe

wiringissimilar,thegeneralcontrolloopcircuitbreaker

shouldmeetthefollowingrequirements:

Theclosingandtrippingcoilaccordingtotheshort-time

currentthroughthedesign,afterthecompletionofthetask,

shouldmaketheloopcurrentinterruption;II,notonlycan

manualremotecontrolshouldalsobeabletocarryoutthe

automatictrippingandclosinginprotectionorautomatic

device;3,toreflectthepositionsignalofthecircuitbreaker

closingortripping;clearsignal4andtohavedifference

betweenmanualandautomaticjumpclosing;5,topreventthe

breakerclosingrepeatedly"jump"lockingdevice;the

integrity,canmonitorthepowersupplyandthenextoperation

loop.

16.Whatisthe"ground“ontheelectrical?

Answer:electricalequipmentinoperation,

Ifthegroundingshort-circuitoccurs,thentheshort-circuit

currentthroughthegroundingbody,andthehemispherical

surfaceformedinthediaspora,asshowninthefigure,the

hemisphericalsurfaceissmal1andtheflowresistance

increases,theshort-circuitcurrentbythevoltagedropis

biggerhere.Therefore,nearthegroundingbody,thehemisphere

issmall,theresistanceisgreat,thecurrenthereishigh,

andconversely,inthefardistancegroundingbody,becausethe

hemisphereislarge,theresistanceissmall,thepotentialis

low.Testshaveshownthat,intheabsenceofasinglegrounding

orgroundingelectrode20m,thesphereisalreadylarge,its

resistanceiszero,weputthepotentialiszero,called

electricalandground..

17.Whatistheshort-circuitvoltageofthetransformer?

Answer:shortcircuitvoltageisoneofthemainparametersof

thetransformer,itisthroughtheshort-circuittestmeasured,

themeasurementmethodis:thesecondarysideofthe

transformershort-circuitcurrent,primarysidepressureto

reachtheratedvalue,thevoltageofVDprimarysideandcalled

shortcircuitvoltage,shortcircuitvoltageisgenerally

percentsaidthewindingpressureusuallythenameplatesaid

shortcircuitvoltageisshortcircuitvoltageVDandthetest

oftheratedvoltageofVeisexpressedasapercentageofVD%

=VDe/Ve*100%.

18,measuringcapacitorshouldpayattentiontowhatmatters?

Answer:1.Whenmeasuringwithamultimeter,theappropriate

gearshallbeselectedaccordingtothecapacitorandtherated

voltage.Forexample:capacitorusedinelectricpower

equipment,generallyatalowvoltageofonlyafewvoltsto

thousandsofvolts,ifusingamultimeterR*1CKgear

measurement,becausethevoltageinthetableis15~22.5volt

battery,islikelytomakethecapacitorbreakdown,itshould

useR*IKgearmeasurement;

Second,forthecapacitorjustremovedfromtheline,must

dischargethecapacitorbeforethemeasurement,inorderto

preventtheremnantsofthechairinthecapacitortodischarge

theinstrument,theinstrument,thedamage;forhigher

operatingvoltage,largecapacitycapacitor,enoughto

dischargethecapacitor,theoperatorshouldtheprotective

measuresofdischarge,topreventelectricshockaccidents.