查表法求取煤矿井下低压电网两相短路电流

1、查表法求取煤矿井下低压电网两相短路电流计算短路电流的目的计算两相短路电流I：校验短路保护的灵敏系数。计算最大三相短路电流imax:校验断路器的切断能力。同一"1(2)/3H.866.Ik3)-k12k1k1换算长度换算原则：电缆换算前后阻抗不变。L、截面为A,均换算成截面积为煤矿井下低压各种截面积的动力电缆，其长度为50mm2的电缆，查表求取两相短路电流1舄。换算长度为Leq=keqL（D2一，、Leq-电缆的换算长度，即把实际长度换算成标准截面为50mm的长度m;eqL-电缆的实际长度，m;keq-换算系数。见表1、表2.Jq换算原则：换算前后阻抗相等。即,r0LX0L=r50Le

2、q'X50Leqr0x2L2FX；0Leqeq"I"22L.r50X50表1煤矿井下1140V、660V380V低压电缆换算系数(keq)额定电压等级Un（V）380、660、1140电缆截面A（mm2）4610162535507095换算系数keq12.078.114.753.011.911.361.000.710.53*摘自矿山电工学（修订本）束昌干，煤炭工业出版社，2012年3月第1版，P58,表2-8查表法计算煤矿井下两相短路电流I案的步骤在供电系统图中选定短路计算点；利用公式（1）计算短路点至变压器二次侧各段电缆的换算长度Leqeq计算总换算长度Lgeq。

3、即=LeqskeqgLeqg-Leqi.(2)L-短路点至电源的全部电缆总换算长度，m;/eqLeqs-电源系统电抗的换算长度,m（查表3）qkacc-高压电缆（6kv,10kV）换算系数（查表4,表5）;eqg高压电缆折算至低压侧的原则：阻抗相等折算前的阻抗为：Ri=r°Li,Xi=%Lir0,%为高压电缆每千米长的电阻、电抗值,9km。Li高压电缆的计算长度，km折算至低压侧，的阻抗为:1X'U21xlA：Xi=XiI=XoLI2截面为50mm的阻抗为R50=r50Leq,X50=X50Leq折算系数keqq为:eqgV(Rl+(X：2=«R20+X；01卜位1

4、+X°L位11"(r50Leq''(X50LeqLa-高压电缆实际上长度，m;gLeqi.-变压器二次侧各段电缆换算长度m.电缆的换算长度可查表求取.根据变压器容量、二次侧电压等级、电缆的总换算长，度查表求得两相短路电流。隔爆型移动变电站干式变压器技术参数：短路损耗AP、短路电压百分数u%,是产品出厂检验的实测值，各生产厂家的产品有所不同。但是，站在工程的角度上看，差不多。表5表7中移动变电站的技术参数取自GB8286-2005矿用隔爆型移动变电站。表3电源系统电抗的换算长度（La。）eqs系统容量（MV.A）25304050100额定电压（V）40014.

5、111.78.87.03.5166041.834.926.120.910.461140126.5105.479.163.331.63*摘自矿山电工学（修订本）束昌干，煤炭工业出版社，2012年3月第1版，P61,表2-11表5矿用高压10kV电缆换算到低压侧电缆长度的换算系数（k）eqg电缆芯线材料铜芯（10kV铜芯电缆，换算至50mm2对应电压等级下的换算系数）额定电压（V）38066011403300矿用10kV铜芯电缆，截面积2（mm）160.00420.01260.03750.3144250.00270.00810.02410.2017350.00190.00580.01730.144

6、7500.00140.00410.01220.1022700.0010.0030.00890.0742950.00070.00230.00670.05621200.00060.00180.00550.0461500.00050.00150.00460.0385表6电网电压1140V、660V、380V时矿用电缆不同芯线截面的换算长度（m电缆截面（mn2）46101625355070957算系数电缆金际、长度（m）、12.078.114.753.011.911.361.000.710.53101218114830191410752024116295603827201411303622431439

7、057413021164048332419012076544028215060440623815196685036276072448728518111582604332708455683332111349570503780966649380241153109805742901086730428271172122906448100120781147530119113610071531101328892523331210150110785812014489735703612291631208564130156910546183912481771309269140169011356654212671

8、901409974150181112177134522872041501078016019311298760482306218160114851702052137980851232523117012190180217314608555423442451801289519022931541903572363258190135101200241416229506023822722001421062102535170359986328401828621014911122026551784104566242029922015611723027761865109369243931323016312224

9、0289719461140722458326240170127250301820281187.5753478340250178133260313821091235783497354260185138270325921901283813516367270192143280338022711330843535381280199148290350023521378873554394290206154300362124331425903573408300213159310374225141473933592422310220164320386225951520963611435320227170330

10、398326761568993630449330234175340410427571615102364946234024118035042252839166310546694763502491863604345292017101084688490360256191370446630011758111470750337026319638045873082180511447265173802702013904707316318531174745530390277207400482832441900120476454440028421241049493325194812347835584102912

11、174205069340619951264802571420298223430519034872043129482158543030522844053113568209013248405984403122334505432365021381355860612450320239460555237312185138587962646032724447056733812223314158986394703342494805794389322801445917653480341254490591439742328147593666649034826050060354055237515059556805

12、003552655106156413624231535974694510362270520627642172470156599370752036927653063974298251815951012721530376281540651843792565162510317345403832865506639446126131656105174855039129256067594542266016861070762560398297570688046232708171610897755704053025807001470427551746110878958041230759071214785280

13、317761127802590419313600724248662850180611468166004263186107363494728981836116583061043332362074835028294518661184843620440329630760451092993189612038576304473346407725519030401926122287064045433965078465272308819571242884650462345660796653533135198712618986604693506708087543431832017128091167047635

14、568082085515323020471299925680483360690832855963278207713189386904903667008449567733252107133795270049737171085705758337321371356966710504376720869058393420216713759797205113827308811592034682197139499373051838774089326001351522271413100674052539275090536083356322581433102075053339876091736164361022

15、881452103476054040377092946245365823181471104777054840878094156326370523481490106178055441379095356407375323781509107479056141980096566488380024081528108880056842481097776569384824381547110281057542982098976650389524681566111582058243583010018673139432498158511298305894408401013968123990252816041142

16、8405964458501026068944037.5255916241156850604451860103806975408525891643117086061145687010501705641332619166211838706184618801062271374180264916811197880625466890107427218422826791700121089063247290010863729942752709171912249006394779101098473804323273917381238910646482920111047461437027691757125192

17、065348893011225754244182799177612659306604939401134676234465282917951278940667498950114677705451328601815129295067550496011587778645602890183413069606825099701170878674608292018531319970689514980118297948465529501872133398069652099011949802947032980189113469907035251000120708110475030101910136010007

18、105301010121918191479830401929137410107175351020123118272484530701948138710207245411030124328353489331001967140110307315461040125538434494031301986141410407385511050126748516498831612006142810507465571060127948597503531912025144121060753562107012915867850833221204414551070760567108013036875951303251

19、20631469108076757210901315688405178328120821482109077457811001327789215225331121011496110078158311101339890025272.53341.12120.11509.61110788.1588112013518908353203371.22139.21523.21120795.259411301363991645367.53401.32158.31536.81130802.3599114013760924554153431.42177.41550.41140809.4604115013881932

20、75462.53461.52196.515641150816.5610116014001940855103491.62215.61577.61160823.661511701412294895557.53521.72234.71591.21170830.7620118014243957056053551.82253.81604.81180837.862511901436396515652.53581.92272.91618.41190844.963112001448497325700361222921632120085263612101460598135747.53642.12311.1164

21、5.61210859.1641122014725989457953672.22330.21659.21220866.264712301484699755842.53702.32349.31672.81230873.36521240149671005658903732.42368.41686.41240880.4657125015088101385937.53762.52387.517001250887.56631260152081021959853792.62406.61713.61260894.6668127015329103006032.53822.72425.71727.21270901

22、.76731280154501038160803852.82444.81740.81280908.8678129015570104626127.53882.92463.91754.41290915.96841300156911054361753913248317681300923689131015812106246222.53943.12502.11781.61310930.16941320159321070562703973.22521.21795.21320937.2700133016053107866317.54003.32540.31808.81330944.3705134016174

23、1086763654033.42559.41822.41340951.4710135016295109496412.54063.52578.518361350958.57161360164151103064604093.62597.61849.61360965.6721137016536111116507.54123.72616.71863.21370972.77261380166571119265554153.82635.81876.81380979.8731139016777112736602.54183.92654.91890.41390986.973714001689811354665

24、04214267419041400994742141017019114356697.54244.12693.11917.614101001.17471420171391151667454274.22712.21931.214201008.2753143017260115976792.54304.32731.31944.814301015.37581440173811167868404334.42750.41958.414401022.4763145017502117606887.54364.52769.5197214501029.57691460176221184169354394.62788

25、.61985.614601036.6774147017743119226982.54424.72807.71999.214701043.77791480178641200370304454.82826.82012.814801050.8784149017984120847077.54484.92845.92026.414901057.979015001810512165712545152865204015001065795151018226122467172.54545.12884.12053.615101072.18001520183461232772204575.22903.22067.2

26、15201079.2806153018467124087267.54605.32922.32080.815301086.38111540185881248973154635.42941.42094.415401093.4816155018709125717362.54665.52960.5210815501100.58221560188291265274104695.62979.62121.615601107.6827157018950127337457.54725.72998.72135.215701114.78321580190711281475054755.83017.82148.815

27、801121.8837159019191128957552.54785.93036.92162.415901128.984316001931212976760048163056217616001136848161019433130577647.54846.13075.12189.616101143.18531620195531313876954876.23094.22203.216201150.2859163019674132197742.54906.33113.32216.816301157.38641640197951330077904936.43132.42230.416401164.4

28、869165019916133827837.54966.53151.5224416501171.58751660200361346378854996.63170.62257.616601178.6880167020157135447932.55026.73189.72271.216701185.78851680202781362579805056.83208.82284.816801192.8890169020398137068027.55086.93227.92298.416901199.9896170020519137878075511732472312170012079011720207

29、601394981705177.23285.22339.217201221.2912173020881140308217.55207.33304.32352.817301228.39171740210021411182655237.43323.42366.417401235.4922175021123141938312.55267.53342.5238017501242.59281760212431427483605297.63361.62393.617601249.6933177021364143558407.55327.73380.72407.217701256.7938178021485

30、1443684555357.83399.82420.817801263.8943179021605145178502.55387.93418.92434.417901270.994918002172614598855054183438244818001278954181021847146798597.55448.13457.12461.618101285.19591820219671476086455478.23476.22475.218201292.2965183022088148418692.55508.33495.32488.818301299.397018402220914922874

31、05538.43514.42502.418401306.4975185022330150048787.55568.53533.5251618501313.59811860224501508588355598.63552.62529.618601320.6986187022571151668882.55628.73571.72543.218701327.79911880226921524789305658.83590.82556.818801334.8996189022812153288977.55688.93609.92570.418901341.91002190022933154099025

32、571936292584190013491007191023054154909072.55749.13648.12597.619101356.110121920231741557191205779.23667.22611.219201363.21018193023295156529167.55809.33686.32624.819301370.310231940234161573392155839.43705.42638.419401377.41028195023537158169262.55869.53724.5265219501384.510341960236571589693105899

33、.63743.62665.619601391.61039197023778159779357.55929.73762.72679.219701398.710441980238991605894055959.83781.82692.819801405.81049199024019161399453599038012706199014131055200024140162209500602038202720200014201060表8KSGZY型移动变电站二次额定电压为1200V系统两相短路电流（A电缆换算长度（m）变压器容量（kVA）3155006308001000315+315125016000

34、291746294773555364075834110961273220287025144658540062105638101781151740281943884530522559805423926710331602766425443925307573051998422926080271241164248484154704971766683281002656397541024643521147467003753112025993835395544474956452864246850140254236973810425747114318592062681602486356336694073447

35、941195481576918024293433353238974260393150955337200237333073400373040543755478949942202318318732743572386335894484465924022643073315334243684343441904341260221129643039328435183290395240832802159286029303153336431553738385330021092762282730303221302935453647320206026692730291530881911337134063402012

36、258026372807296428013212329336019662497255027052849269830673140380192124172467261027412601293430004001877234223892520264025112812287242018352271231524362546242627002754440179520232244235624582346259626454601755213921782281237522712499254448017172078211422112298220024092451500168020202054214422252133

37、232623645201645196519972081215620702248228354016111913194320212091201021752208560157716831892196420301954210621375801545181518431911197219002041207060015141770179618601917184919812008620148417261751181118651801192419496401455168517081765181517551870189366014271645166817211768171118181841680140016071

38、629167917241669177017917001374157115911639168116291724174472013491536155616011640159116811699740134215031521156416021555163916577601301147114891529156515201599161678012781440145714951529148715621578800125514111427146314961455152615418201234138213981432146314241492149984012131355137014031432139514591

39、472860119313291343137414021367142714408801173130313171347137413391397141090011541279129213211346131313681380920113512551268129513201288134113529401117123312451271129412641314132596011001211122212481270124112881299980108311891201122512461218126412741000106711691180120312231196124012501050102711211131

40、1151117011451184119311009911076108511041121109811341142115095710351043106010761055108710941200925996100410201034101510441051125089596196898399597810041010130086692893494895994396797313508408979039159269119339381400815867873885895881901906145079184084685686685287287615007698158208308388268448481550747790795805813801817821160072776877278178977879379716507087467517597667557707731700690726730738744735748751175067370771071872471572773018006576886926997056967087111850641671674681686678689692190062665465866466966167267419506126396426486536456556572000598624627632