查表法求取煤礦井下低壓電網(wǎng)兩相短路電流

1、查表法求取煤礦井下低壓電網(wǎng)兩相短路電流 計(jì)算短路電流的目的計(jì)算兩相短路電流I：校驗(yàn)短路保護(hù)的靈敏系數(shù)。計(jì)算最大三相短路電流i max:校驗(yàn)斷路器的切斷能力。同一"1(2) /3 H.866.Ik3)-k1 2 k1k1換算長(zhǎng)度換算原則：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(dòng)力電纜，其長(zhǎng)度為50mm2的電纜，查表求取兩相短路電流1舄。換算長(zhǎng)度為L(zhǎng)eq = keqL（D2 一， 、Leq-電纜的換算長(zhǎng)度，即把實(shí)際長(zhǎng)度換算成標(biāo)準(zhǔn)截面為50 mm的長(zhǎng)度m;eqL-電纜的實(shí)際長(zhǎng)度，m;keq-換算系數(shù)。見表1、表2. Jq換算原則：換算前后阻抗相等。即,

2、 r0LX0L=r50Leq' X50Leqr0 x2 L2 F X；0 Leqeq " I "22L . r50X50表1煤礦井下1140V、660V 380V低壓電纜換算系數(shù)(keq)額定電壓等級(jí)Un（V）380、 660、 1140電纜截面A （ m m2）4610162535507095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， 2012年3月第1版，P58,表2-8查表法計(jì)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(jì)算點(diǎn)；利用公式（1）計(jì)算短路點(diǎn)至變

3、壓器二次側(cè)各段電纜的換算長(zhǎng)度Leqeq計(jì)算總換算長(zhǎng)度Lgeq。即= LeqskeqgLeqg- Leqi.(2)L -短路點(diǎn)至電源的全部電纜總換算長(zhǎng)度 ，m;/ eqLeqs-電源系統(tǒng)電抗的換算長(zhǎng)度,m （查表3） qkacc -高壓電纜（6kv, 10kV）換算系數(shù)（查表4,表5）; eq g高壓電纜折算至低壓側(cè)的原則：阻抗相等折算前的阻抗為：Ri =r°Li, Xi =%Lir0, %為高壓電纜每千米長(zhǎng)的電阻、電抗值,9km。Li高壓電纜的計(jì)算長(zhǎng)度，km折算至低壓側(cè)，的阻抗為:1 X 'U2 1 xlA ：X i =Xi I =XoL I2截面為 50 mm 的阻抗為 R

4、50 = r50 Leq , X50 = X50 Leq折算系數(shù)keqq為: eq gV(Rl +(X：2 =«R20 +X；01卜位1 + X°L位11 "(r50 Leq ''(X50LeqLa-高壓電纜實(shí)際上長(zhǎng)度，m; gLeqi.-變壓器二次側(cè)各段電纜換算長(zhǎng)度m.電纜的換算長(zhǎng)度可查表求取.根據(jù)變壓器容量、二次側(cè)電壓等級(jí)、電纜的總換算長(zhǎng)，度查表求得兩相短路電流。隔爆型移動(dòng)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(yàn)的實(shí)測(cè)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(dòng)變電站的技術(shù)參數(shù)

5、取自GB8286-2005礦用隔爆型移動(dòng)變電站。表3電源系統(tǒng)電抗的換算長(zhǎng)度（La。） eq s系統(tǒng)容量（MV.A）25304050100額定電壓（V）40014.111.78.87.03.5166041.834.926.120.910.461140126.5105.479.163.331.63*摘自礦山電工學(xué)（修訂本）束昌干，煤炭工業(yè)出版社，2012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(zhǎng)度的換算系數(shù)（ k ）eq g電纜芯線材料銅芯（10kV銅芯電纜，換算至50 mm2對(duì)應(yīng)電壓等級(jí)下的換算系數(shù)）額定電壓（V）38066011403300礦用10kV銅芯電纜，

6、截面積2（mm）160.00420.01260.03750.3144250.00270.00810.02410.2017350.00190.00580.01730.1447500.00140.00410.01220.1022700.0010.0030.00890.0742950.00070.00230.00670.05621200.00060.00180.00550.0461500.00050.00150.00460.0385表6 電網(wǎng)電壓1140V、660V、380V時(shí)礦用電纜不同芯線截面的換算長(zhǎng)度（ m電纜截面（mn2）46101625355070957算系數(shù) 電纜金際、長(zhǎng)度（m）、12.

7、078.114.753.011.911.361.000.710.5310121811483019141075202411629560382720141130362243143905741302116404833241901207654402821506044062381519668503627607244872851811158260433270845568333211134957050378096664938024115310980574290108673042827117212290644810012078114753011911361007153110132889252333121015

8、011078581201448973570361229163120856413015691054618391248177130926914016901135665421267190140997415018111217713452287204150107801601931129876048230621816011485170205213798085123252311701219018021731460855542344245180128951902293154190357236325819013510120024141622950602382272200142106210253517035998

9、63284018286210149111220265517841045662420299220156117230277618651093692439313230163122240289719461140722458326240170127250301820281187.575347834025017813326031382109123578349735426018513827032592190128381351636727019214328033802271133084353538128019914829035002352137887355439429020615430036212433142

10、590357340830021315931037422514147393359242231022016432038622595152096361143532022717033039832676156899363044933023417534041042757161510236494623402411803504225283916631054669476350249186360434529201710108468849036025619137044663001175811147075033702631963804587308218051144726517380270201390470731631

11、853117474553039027720740048283244190012047645444002842124104949332519481234783558410291217420506934061995126480257142029822343051903487204312948215854303052284405311356820901324840598440312233450543236502138135586061245032023946055523731218513858796264603272444705673381222331415898639470334249480579

12、438932280144591765348034125449059143974232814759366664903482605006035405523751505955680500355265510615641362423153597469451036227052062764217247015659937075203692765306397429825181595101272153037628154065184379256516251031734540383286550663944612613165610517485503912925606759454226601686107076256039

13、829757068804623270817161089775570405302580700147042755174611087895804123075907121478528031776112780259041931360072424866285018061146816600426318610736349472898183611658306104333236207483502829451866118484362044032963076045109299318961203857630447334640772551903040192612228706404543396507846527230881

14、957124288465046234566079665353313519871261898660469350670808754343183201712809116704763556808208551532302047129992568048336069083285596327820771318938690490366700844956773325210713379527004973717108570575833732137135696671050437672086905839342021671375979720511382730881159203468219713949937305183877

15、408932600135152227141310067405253927509053608335632258143310207505333987609173616436102288145210347605404037709294624536582318147110477705484087809415632637052348149010617805544137909535640737532378150910747905614198009656648838002408152810888005684248109777656938482438154711028105754298209897665038

16、95246815661115820582435830100186731394324981585112983058944084010139681239902528160411428405964458501026068944037.525591624115685060445186010380697540852589164311708606114568701050170564133261916621183870618461880106227137418026491681119788062546689010742721842282679170012108906324729001086372994275

17、270917191224900639477910109847380432327391738123891064648292011104746143702769175712519206534889301122575424418279917761265930660493940113467623446528291795127894066749895011467770545132860181512929506755049601158777864560289018341306960682509970117087867460829201853131997068951498011829794846552950

18、187213339806965209901194980294703298018911346990703525100012070811047503010191013601000710530101012191819147983040192913741010717535102012311827248453070194813871020724541103012432835348933100196714011030731546104012553843449403130198614141040738551105012674851649883161200614281050746557106012794859

19、750353191202514412106075356210701291586785083322120441455107076056710801303687595130325120631469108076757210901315688405178328120821482109077457811001327789215225331121011496110078158311101339890025272.53341.12120.11509.61110788.1588112013518908353203371.22139.21523.21120795.259411301363991645367.53

20、401.32158.31536.81130802.3599114013760924554153431.42177.41550.41140809.460411501388193275462.53461.52196.515641150816.5610116014001940855103491.62215.61577.61160823.661511701412294895557.53521.72234.71591.21170830.7620118014243957056053551.82253.81604.81180837.862511901436396515652.53581.92272.9161

21、8.41190844.963112001448497325700361222921632120085263612101460598135747.53642.12311.11645.61210859.1641122014725989457953672.22330.21659.21220866.264712301484699755842.53702.32349.31672.81230873.36521240149671005658903732.42368.41686.41240880.4657125015088101385937.53762.52387.517001250887.566312601

22、52081021959853792.62406.61713.61260894.6668127015329103006032.53822.72425.71727.21270901.76731280154501038160803852.82444.81740.81280908.8678129015570104626127.53882.92463.91754.41290915.96841300156911054361753913248317681300923689131015812106246222.53943.12502.11781.61310930.16941320159321070562703

23、973.22521.21795.21320937.2700133016053107866317.54003.32540.31808.81330944.37051340161741086763654033.42559.41822.41340951.4710135016295109496412.54063.52578.518361350958.57161360164151103064604093.62597.61849.61360965.6721137016536111116507.54123.72616.71863.21370972.77261380166571119265554153.8263

24、5.81876.81380979.8731139016777112736602.54183.92654.91890.41390986.97371400168981135466504214267419041400994742141017019114356697.54244.12693.11917.614101001.17471420171391151667454274.22712.21931.214201008.2753143017260115976792.54304.32731.31944.814301015.37581440173811167868404334.42750.41958.414

25、401022.4763145017502117606887.54364.52769.5197214501029.57691460176221184169354394.62788.61985.614601036.6774147017743119226982.54424.72807.71999.214701043.77791480178641200370304454.82826.82012.814801050.8784149017984120847077.54484.92845.92026.414901057.97901500181051216571254515286520401500106579

26、5151018226122467172.54545.12884.12053.615101072.18001520183461232772204575.22903.22067.215201079.2806153018467124087267.54605.32922.32080.815301086.38111540185881248973154635.42941.42094.415401093.4816155018709125717362.54665.52960.5210815501100.58221560188291265274104695.62979.62121.615601107.68271

27、57018950127337457.54725.72998.72135.215701114.78321580190711281475054755.83017.82148.815801121.8837159019191128957552.54785.93036.92162.415901128.984316001931212976760048163056217616001136848161019433130577647.54846.13075.12189.616101143.18531620195531313876954876.23094.22203.216201150.2859163019674

28、132197742.54906.33113.32216.816301157.38641640197951330077904936.43132.42230.416401164.4869165019916133827837.54966.53151.5224416501171.58751660200361346378854996.63170.62257.616601178.6880167020157135447932.55026.73189.72271.216701185.78851680202781362579805056.83208.82284.816801192.889016902039813

29、7068027.55086.93227.92298.416901199.9896170020519137878075511732472312170012079011720207601394981705177.23285.22339.217201221.2912173020881140308217.55207.33304.32352.817301228.39171740210021411182655237.43323.42366.417401235.4922175021123141938312.55267.53342.5238017501242.5928176021243142748360529

30、7.63361.62393.617601249.6933177021364143558407.55327.73380.72407.217701256.79381780214851443684555357.83399.82420.817801263.8943179021605145178502.55387.93418.92434.417901270.994918002172614598855054183438244818001278954181021847146798597.55448.13457.12461.618101285.19591820219671476086455478.23476.

31、22475.218201292.2965183022088148418692.55508.33495.32488.818301299.39701840222091492287405538.43514.42502.418401306.4975185022330150048787.55568.53533.5251618501313.59811860224501508588355598.63552.62529.618601320.6986187022571151668882.55628.73571.72543.218701327.79911880226921524789305658.83590.82

32、556.818801334.8996189022812153288977.55688.93609.92570.418901341.91002190022933154099025571936292584190013491007191023054154909072.55749.13648.12597.619101356.110121920231741557191205779.23667.22611.219201363.21018193023295156529167.55809.33686.32624.819301370.310231940234161573392155839.43705.42638

33、.419401377.41028195023537158169262.55869.53724.5265219501384.510341960236571589693105899.63743.62665.619601391.61039197023778159779357.55929.73762.72679.219701398.710441980238991605894055959.83781.82692.819801405.810491990240191613994535990380127061990141310552000241401622095006020382027202000142010

34、60表8 KSGZY型移動(dòng)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(zhǎng)度（m）變壓器容量（kVA）3155006308001000315+315125016000291746294773555364075834110961273220287025144658540062105638101781151740281943884530522559805423926710331602766425443925307573051998422926080271241164248484154704971766683281002656397541024643521147467003753112

35、025993835395544474956452864246850140254236973810425747114318592062681602486356336694073447941195481576918024293433353238974260393150955337200237333073400373040543755478949942202318318732743572386335894484465924022643073315334243684343441904341260221129643039328435183290395240832802159286029303153336

36、431553738385330021092762282730303221302935453647320206026692730291530881911337134063402012258026372807296428013212329336019662497255027052849269830673140380192124172467261027412601293430004001877234223892520264025112812287242018352271231524362546242627002754440179520232244235624582346259626454601755

37、213921782281237522712499254448017172078211422112298220024092451500168020202054214422252133232623645201645196519972081215620702248228354016111913194320212091201021752208560157716831892196420301954210621375801545181518431911197219002041207060015141770179618601917184919812008620148417261751181118651801

38、192419496401455168517081765181517551870189366014271645166817211768171118181841680140016071629167917241669177017917001374157115911639168116291724174472013491536155616011640159116811699740134215031521156416021555163916577601301147114891529156515201599161678012781440145714951529148715621578800125514111

39、427146314961455152615418201234138213981432146314241492149984012131355137014031432139514591472860119313291343137414021367142714408801173130313171347137413391397141090011541279129213211346131313681380920113512551268129513201288134113529401117123312451271129412641314132596011001211122212481270124112881

40、29998010831189120112251246121812641274100010671169118012031223119612401250105010271121113111511170114511841193110099110761085110411211098113411421150957103510431060107610551087109412009259961004102010341015104410511250895961968983995978100410101300866928934948959943967973135084089790391592691193393814008158678738858958819019061450791840846856866852872876150076981582083083882684484815507477907958058138018178211600727768772781789778793797165070874675175976675577077317006907267307387447357487511750673707710718724715727730180065768869269970569670871118506416716746816866786