1、查表法求取煤礦井下低壓電網(wǎng)兩相短路電流計算短路電流的目的計算兩相短路電流I：校驗短路保護(hù)的靈敏系數(shù).計算最大三相短路電流imax:校驗斷路器的切斷水平.同一1(2)/3H.866.Ik3)-k12k1k1換算長度換算原那么：電纜換算前后阻抗不變.L、截面為A,均換算成截面積為煤礦井下低壓各種截面積的動力電纜,其長度為50mm2的電纜,查表求取兩相短路電流1舄.換算長度為Leq=keqLD2一,、Leq-電纜的換算長度,即把實際長度換算成標(biāo)準(zhǔn)截面為50mm的長度m;eqL-電纜的實際長度,m;keq-換算系數(shù).見表1、表2.Jq換算原那么：換算前后阻抗相等.即,r0LX0L=r50LeqX50L

2、eqr0x2L2FX；0LeqeqI22L.r50X50表1煤礦井下1140V、660V380V低壓電纜換算系數(shù)(keq)額定電壓等級UnV380、660、1140電纜截面Amm24610162535507095換算系數(shù)keq12.078.114.753.011.911.361.000.710.53*摘自?礦山電工學(xué)?修訂本束昌干,煤炭工業(yè)出版社,2021年3月第1版,P58,表2-8查表法計算煤礦井下兩相短路電流I案的步驟在供電系統(tǒng)圖中選定短路計算點；利用公式1計算短路點至變壓器二次側(cè)各段電纜的換算長度Leqeq計算總換算長度Lgeq.即=LeqskeqgLeqg-Leqi.(2)L-短路點

3、至電源的全部電纜總換算長度,m;/eqLeqs-電源系統(tǒng)電抗的換算長度,m查表3qkacc-高壓電纜6kv,10kV換算系數(shù)查表4,表5;eqg高壓電纜折算至低壓側(cè)的原那么：阻抗相等折算前的阻抗為：Ri=rLi,Xi=%Lir0,%為高壓電纜每千米長的電阻、電抗值,9km.Li高壓電纜的計算長度,km折算至低壓側(cè),的阻抗為:1XU21xlA：Xi=XiI=XoLI2截面為50mm的阻抗為R50=r50Leq,X50=X50Leq折算系數(shù)keqq為:eqgV(Rl+(X：2=R20+X；01卜位1+XL位11(r50Leq(X50LeqLa-高壓電纜實際上長度,m;gLeqi.-變壓器二次側(cè)各段

4、電纜換算長度m.電纜的換算長度可查表求取.根據(jù)變壓器容量、二次側(cè)電壓等級、電纜的總換算長,度查表求得兩相短路電流.隔爆型移動變電站干式變壓器技術(shù)參數(shù)：短路損耗AP、短路電壓百分?jǐn)?shù)u%,是產(chǎn)品出廠檢驗的實測值,各生產(chǎn)廠家的產(chǎn)品有所不同.但是,站在工程的角度上看,差不多.表5表7中移動變電站的技術(shù)參數(shù)取自GB8286-2005?礦用隔爆型移動變電站?.表3電源系統(tǒng)電抗的換算長度La.eqs系統(tǒng)容量MV.A25304050100額定電壓V40014.111.78.87.03.5166041.834.926.120.910.461140126.5105.479.163.331.63*摘自?礦山電工學(xué)?

5、修訂本束昌干,煤炭工業(yè)出版社,2021年3月第1版,P61,表2-11表5礦用高壓10kV電纜換算到低壓側(cè)電纜長度的換算系數(shù)keqg電纜芯線材料銅芯10kV銅芯電纜,換算至50mm2對應(yīng)電壓等級下的換算系數(shù)額定電壓V38066011403300礦用10kV銅芯電纜,截面積2mm160.00420.01260.03750.3144250.00270.00810.02410.2021350.00190.00580.01730.1447500.00140.00410.01220.1022700.0010.0030.00890.0742950.00070.00230.00670.05621200.00

6、060.00180.00550.0461500.00050.00150.00460.0385表6電網(wǎng)電壓1140V、660V、380V時礦用電纜不同芯線截面的換算長度m電纜截面mn246101625355070957算系數(shù)電纜金際、長度m、12.078.114.753.011.911.361.000.710.5310121811483019141075202411629560382720141130362243143905741302116404833241901207654402821506044062381519668503627607244872851811158260433270845

7、568333211134957050378096664938024115310980574290108673042827117212290644810012078114753011911361007153110132889252333121015011078581201448973570361229163120856413015691054618391248177130926914016901135665421267190140997415018111217713452287204150107801601931129876048230621816011485170205213798085123

8、25231170121901802173146085554234424518012895190229315419035723632581901351012002414162295060238227220014210621025351703599863284018286210149111220265517841045662420299220156117230277618651093692439313230163122240289719461140722458326240170127250301820281187.575347834025017813326031382109123578349735

9、426018513827032592190128381351636727019214328033802271133084353538128019914829035002352137887355439429020615430036212433142590357340830021315931037422514147393359242231022016432038622595152096361143532022717033039832676156899363044933023417534041042757161510236494623402411803504225283916631054669476

10、350249186360434529201710108468849036025619137044663001175811147075033702631963804587308218051144726517380270201390470731631853117474553039027720740048283244190012047645444002842124104949332519481234783558410291217420506934061995126480257142029822343051903487204312948215854303052284405311356820901324

11、840598440312233450543236502138135586061245032023946055523731218513858796264603272444705673381222331415898639470334249480579438932280144591765348034125449059143974232814759366664903482605006035405523751505955680500355265510615641362423153597469451036227052062764217247015659937075203692765306397429825

12、181595101272153037628154065184379256516251031734540383286550663944612613165610517485503912925606759454226601686107076256039829757068804623270817161089775570405302580700147042755174611087895804123075907121478528031776112780259041931360072424866285018061146816600426318610736349472898183611658306104333

13、236207483502829451866118484362044032963076045109299318961203857630447334640772551903040192612228706404543396507846527230881957124288465046234566079665353313519871261898660469350670808754343183202112809116704763556808208551532302047129992568048336069083285596327820771318938690490366700844956773325210

14、713379527004973717108570575833732137135696671050437672086905839342021671375979720511382730881159203468219713949937305183877408932600135152227141310067405253927509053608335632258143310207505333987609173616436102288145210347605404037709294624536582318147110477705484087809415632637052348149010617805544

15、13790953564073753237815091074790561419800965664883800240815281088800568424810977765693848243815471102810575429820989766503895246815661115820582435830100186731394324981585112983058944084010139681239902528160411428405964458501026068944037.525591624115685060445186010380697540852589164311708606114568701

16、050170564133261916621183870618461880106227137418026491681119788062546689010742721842282679170012108906324729001086372994275270917191224900639477910109847380432327391738123891064648292011104746143702769175712519206534889301122575424418279917761265930660493940113467623446528291795127894066749895011467

17、770545132860181512929506755049601158777864560289018341306960682509970117087867460829201853131997068951498011829794846552950187213339806965209901194980294703298018911346990703525100012070811047503010191013601000710530101012191819147983040192913741010717535102012311827248453070194813871020724541103012

18、432835348933100196714011030731546104012553843449403130198614141040738551105012674851649883161200614281050746557106012794859750353191202514412106075356210701291586785083322120441455107076056710801303687595130325120631469108076757210901315688405178328120821482109077457811001327789215225331121011496110

19、078158311101339890025272.53341.12120.11509.61110788.1588112013518908353203371.22139.21523.21120795.259411301363991645367.53401.32158.31536.81130802.3599114013760924554153431.42177.41550.41140809.460411501388193275462.53461.52196.515641150816.5610116014001940855103491.62215.61577.61160823.66151170141

20、2294895557.53521.72234.71591.21170830.7620118014243957056053551.82253.81604.81180837.862511901436396515652.53581.92272.91618.41190844.963112001448497325700361222921632120085263612101460598135747.53642.12311.11645.61210859.1641122014725989457953672.22330.21659.21220866.264712301484699755842.53702.323

21、49.31672.81230873.36521240149671005658903732.42368.41686.41240880.4657125015088101385937.53762.52387.517001250887.56631260152081021959853792.62406.61713.61260894.6668127015329103006032.53822.72425.71727.21270901.76731280154501038160803852.82444.81740.81280908.8678129015570104626127.53882.92463.91754

22、.41290915.96841300156911054361753913248317681300923689131015812106246222.53943.12502.11781.61310930.16941320159321070562703973.22521.21795.21320937.2700133016053107866317.54003.32540.31808.81330944.37051340161741086763654033.42559.41822.41340951.4710135016295109496412.54063.52578.518361350958.571613

23、60164151103064604093.62597.61849.61360965.6721137016536111116507.54123.72616.71863.21370972.77261380166571119265554153.82635.81876.81380979.8731139016777112736602.54183.92654.91890.41390986.97371400168981135466504214267419041400994742141017019114356697.54244.12693.11917.614101001.1747142017139115166

24、7454274.22712.21931.214201008.2753143017260115976792.54304.32731.31944.814301015.37581440173811167868404334.42750.41958.414401022.4763145017502117606887.54364.52769.5197214501029.57691460176221184169354394.62788.61985.614601036.6774147017743119226982.54424.72807.71999.214701043.777914801786412003703

25、04454.82826.82021.814801050.8784149017984120847077.54484.92845.92026.414901057.979015001810512165712545152865204015001065795151018226122467172.54545.12884.12053.615101072.18001520183461232772204575.22903.22067.215201079.2806153018467124087267.54605.32922.32080.815301086.38111540185881248973154635.42

26、941.42094.415401093.4816155018709125717362.54665.52960.5210815501100.58221560188291265274104695.62979.62121.615601107.6827157018950127337457.54725.72998.72135.215701114.78321580190711281475054755.83017.82148.815801121.8837159019191128957552.54785.93036.92162.415901128.9843160019312129767600481630562

27、17616001136848161019433130577647.54846.13075.12189.616101143.18531620195531313876954876.23094.22203.216201150.2859163019674132197742.54906.33113.32216.816301157.38641640197951330077904936.43132.42230.416401164.4869165019916133827837.54966.53151.5224416501171.58751660200361346378854996.63170.62257.61

28、6601178.6880167020217135447932.55026.73189.72271.216701185.78851680202781362579805056.83208.82284.816801192.8890169020398137068027.55086.93227.92298.416901199.9896170020519137878075511732472312170012079011720207601394981705177.23285.22339.217201221.2912173020881140308217.55207.33304.32352.817301228.

29、39171740210021411182655237.43323.42366.417401235.4922175021123141938312.55267.53342.5238017501242.59281760212431427483605297.63361.62393.617601249.6933177021364143558407.55327.73380.72407.217701256.79381780214851443684555357.83399.82420.817801263.8943179021605145178502.55387.93418.92434.417901270.99

30、4918002172614598855054183438244818001278954181021847146798597.55448.13457.12461.618101285.19591820219671476086455478.23476.22475.218201292.2965183022088148418692.55508.33495.32488.818301299.39701840222091492287405538.43514.42502.418401306.4975185022330150048787.55568.53533.5251618501313.598118602245

31、01508588355598.63552.62529.618601320.6986187022571151668882.55628.73571.72543.218701327.79911880226921524789305658.83590.82556.818801334.8996189022812153288977.55688.93609.92570.418901341.91002190022933154099025571936292584190013491007191023054154909072.55749.13648.12597.619101356.110121920231741557

32、191205779.23667.22611.219201363.21018193023295156529167.55809.33686.32624.819301370.310231940234161573392155839.43705.42638.419401377.41028195023537158169262.55869.53724.5265219501384.510341960236571589693105899.63743.62665.619601391.61039197023778159779357.55929.73762.72679.219701398.71044198023899

33、1605894055959.83781.82692.819801405.81049199024019161399453599038012706199014131055200024140162209500602038202720200014201060表8KSGZY型移動變電站二次額定電壓為1200V系統(tǒng)兩相短路電流A電纜換算長度m變壓器容量kVA3155006308001000315+3151250160002917462947735553640758341109612732202870251446585400621056381017811517402819438845305225598054

34、239267103316027664254439253075730519984229260802712411642484841547049717666832810026563975410246435211474670037531120259938353955444749564528642468501402542369738104257471143185920626816024863563366940734479411954815769180242934333532389742603931509553372002373330734003730405437554789499422023183187

35、327435723863358944844659240226430733153342436843434419043412602211296430393284351832903952408328021592860293031533364315537383853300210927622827303032213029354536473202060266927302915308819113371340634020212580263728072964280132123293360196624972550270528492698306731403801921241724672610274126012934

36、300040018772342238925202640251128122872420183522712315243625462426270027544401795202322442356245823462596264546017552139217822812375227124992544480171720782114221122982200240924515001680202120542144222521332326236452016451965199720812156207022482283540161119131943202120912021217522085601577168318921

37、964203019542106213758015451815184319111972190020412070600151417701796186019171849198120216201484172617511811186518011924194964014551685170817651815175518701893660142716451668172117681711181818416801400160716291679172416691770179170013741571159116391681162917241744720134915361556160116401591168116997

38、401342150315211564160215551639165776013011471148915291565152015991616780127814401457149515291487156215788001255141114271463149614551526154182012341382139814321463142414921499840121313551370140314321395145914728601193132913431374140213671427144088011731303131713471374133913971410900115412791292132113

39、461313136813809201135125512681295132012881341135294011171233124512711294126413141325960110012111222124812701241128812999801083118912011225124612181264127410001067116911801203122311961240125010501027112111311151117011451184119311009911076108511041121109811341142115095710351043106010761055108710941200

40、92599610041020103410151044105112508959619689839959781004101013008669289349489599439679731350840897903915926911933938140081586787388589588190190614507918408468568668528728761500769815820830838826844848155074779079580581380181782116007277687727817897787937971650708746751759766755770773170069072673073874473574875117506737077107187247157277301800657688692699705696708711185064167167468168667868969219006266546586646696616726741950612639642648653645655657200059862462763263763063