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:校验断路器的切断水平.同一"1(2)/3H.866.Ik3)-k12k1k1换算长度换算原那么：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=keqLD2一,、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换算原那么：换算前后阻抗相等.即,r0LX0L=r50L

2、eq'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UnV380、660、1140电缆截面Amm24610162535507095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,2021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.即=Leq

3、skeqgLeqg-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3qkacc-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那么：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+X°L位

4、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.A25304050100额定电压V40014.111.78.87.03.5

5、166041.834.926.120.910.461140126.5105.479.163.331.63*摘自?矿山电工学?修订本束昌干,煤炭工业出版社,2021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keqg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V38066011403300矿用10kV铜芯电缆,截面积2mm160.00420.01260.03750.3144250.00270.00810.02410.2021350.00190.00580.01730.1447500.00140.00410.01220

6、.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mn246101625355070957算系数电缆金际、长度m、12.078.114.753.011.911.361.000.710.53101218114830191410752024116295603827201411303622431439057413021164048332419012076

7、544028215060440623815196685036276072448728518111582604332708455683332111349570503780966649380241153109805742901086730428271172122906448100120781147530119113610071531101328892523331210150110785812014489735703612291631208564130156910546183912481771309269140169011356654212671901409974150181112177134522

8、872041501078016019311298760482306218160114851702052137980851232523117012190180217314608555423442451801289519022931541903572363258190135101200241416229506023822722001421062102535170359986328401828621014911122026551784104566242029922015611723027761865109369243931323016312224028971946114072245832624017

9、0127250301820281187.5753478340250178133260313821091235783497354260185138270325921901283813516367270192143280338022711330843535381280199148290350023521378873554394290206154300362124331425903573408300213159310374225141473933592422310220164320386225951520963611435320227170330398326761568993630449330234

10、175340410427571615102364946234024118035042252839166310546694763502491863604345292017101084688490360256191370446630011758111470750337026319638045873082180511447265173802702013904707316318531174745530390277207400482832441900120476454440028421241049493325194812347835584102912174205069340619951264802571

11、420298223430519034872043129482158543030522844053113568209013248405984403122334505432365021381355860612450320239460555237312185138587962646032724447056733812223314158986394703342494805794389322801445917653480341254490591439742328147593666649034826050060354055237515059556805003552655106156413624231535

12、974694510362270520627642172470156599370752036927653063974298251815951012721530376281540651843792565162510317345403832865506639446126131656105174855039129256067594542266016861070762560398297570688046232708171610897755704053025807001470427551746110878958041230759071214785280317761127802590419313600724

13、248662850180611468166004263186107363494728981836116583061043332362074835028294518661184843620440329630760451092993189612038576304473346407725519030401926122287064045433965078465272308819571242884650462345660796653533135198712618986604693506708087543431832021128091167047635568082085515323020471299925

14、680483360690832855963278207713189386904903667008449567733252107133795270049737171085705758337321371356966710504376720869058393420216713759797205113827308811592034682197139499373051838774089326001351522271413100674052539275090536083356322581433102075053339876091736164361022881452103476054040377092946

15、2453658231814711047770548408780941563263705234814901061780554413790953564073753237815091074790561419800965664883800240815281088800568424810977765693848243815471102810575429820989766503895246815661115820582435830100186731394324981585112983058944084010139681239902528160411428405964458501026068944037.5

16、255916241156850604451860103806975408525891643117086061145687010501705641332619166211838706184618801062271374180264916811197880625466890107427218422826791700121089063247290010863729942752709171912249006394779101098473804323273917381238910646482920111047461437027691757125192065348893011225754244182799

17、177612659306604939401134676234465282917951278940667498950114677705451328601815129295067550496011587778645602890183413069606825099701170878674608292018531319970689514980118297948465529501872133398069652099011949802947032980189113469907035251000120708110475030101910136010007105301010121918191479830401

18、929137410107175351020123118272484530701948138710207245411030124328353489331001967140110307315461040125538434494031301986141410407385511050126748516498831612006142810507465571060127948597503531912025144121060753562107012915867850833221204414551070760567108013036875951303251206314691080767572109013156

19、88405178328120821482109077457811001327789215225331121011496110078158311101339890025272.53341.12120.11509.61110788.1588112013518908353203371.22139.21523.21120795.259411301363991645367.53401.32158.31536.81130802.3599114013760924554153431.42177.41550.41140809.460411501388193275462.53461.52196.515641150

20、816.5610116014001940855103491.62215.61577.61160823.661511701412294895557.53521.72234.71591.21170830.7620118014243957056053551.82253.81604.81180837.862511901436396515652.53581.92272.91618.41190844.963112001448497325700361222921632120085263612101460598135747.53642.12311.11645.61210859.1641122014725989

21、457953672.22330.21659.21220866.264712301484699755842.53702.32349.31672.81230873.36521240149671005658903732.42368.41686.41240880.4657125015088101385937.53762.52387.517001250887.56631260152081021959853792.62406.61713.61260894.6668127015329103006032.53822.72425.71727.21270901.76731280154501038160803852

22、.82444.81740.81280908.8678129015570104626127.53882.92463.91754.41290915.96841300156911054361753913248317681300923689131015812106246222.53943.12502.11781.61310930.16941320159321070562703973.22521.21795.21320937.2700133016053107866317.54003.32540.31808.81330944.37051340161741086763654033.42559.41822.4

23、1340951.4710135016295109496412.54063.52578.518361350958.57161360164151103064604093.62597.61849.61360965.6721137016536111116507.54123.72616.71863.21370972.77261380166571119265554153.82635.81876.81380979.8731139016777112736602.54183.92654.91890.41390986.973714001689811354665042142674190414009947421410

24、17019114356697.54244.12693.11917.614101001.17471420171391151667454274.22712.21931.214201008.2753143017260115976792.54304.32731.31944.814301015.37581440173811167868404334.42750.41958.414401022.4763145017502117606887.54364.52769.5197214501029.57691460176221184169354394.62788.61985.614601036.6774147017

25、743119226982.54424.72807.71999.214701043.77791480178641200370304454.82826.82021.814801050.8784149017984120847077.54484.92845.92026.414901057.979015001810512165712545152865204015001065795151018226122467172.54545.12884.12053.615101072.18001520183461232772204575.22903.22067.215201079.280615301846712408

26、7267.54605.32922.32080.815301086.38111540185881248973154635.42941.42094.415401093.4816155018709125717362.54665.52960.5210815501100.58221560188291265274104695.62979.62121.615601107.6827157018950127337457.54725.72998.72135.215701114.78321580190711281475054755.83017.82148.815801121.88371590191911289575

27、52.54785.93036.92162.415901128.984316001931212976760048163056217616001136848161019433130577647.54846.13075.12189.616101143.18531620195531313876954876.23094.22203.216201150.2859163019674132197742.54906.33113.32216.816301157.38641640197951330077904936.43132.42230.416401164.4869165019916133827837.54966

28、.53151.5224416501171.58751660200361346378854996.63170.62257.616601178.6880167020217135447932.55026.73189.72271.216701185.78851680202781362579805056.83208.82284.816801192.8890169020398137068027.55086.93227.92298.416901199.9896170020519137878075511732472312170012079011720207601394981705177.23285.22339

29、.217201221.2912173020881140308217.55207.33304.32352.817301228.39171740210021411182655237.43323.42366.417401235.4922175021123141938312.55267.53342.5238017501242.59281760212431427483605297.63361.62393.617601249.6933177021364143558407.55327.73380.72407.217701256.79381780214851443684555357.83399.82420.8

30、17801263.8943179021605145178502.55387.93418.92434.417901270.994918002172614598855054183438244818001278954181021847146798597.55448.13457.12461.618101285.19591820219671476086455478.23476.22475.218201292.2965183022088148418692.55508.33495.32488.818301299.39701840222091492287405538.43514.42502.418401306

31、.4975185022330150048787.55568.53533.5251618501313.59811860224501508588355598.63552.62529.618601320.6986187022571151668882.55628.73571.72543.218701327.79911880226921524789305658.83590.82556.818801334.8996189022812153288977.55688.93609.92570.418901341.91002190022933154099025571936292584190013491007191

32、023054154909072.55749.13648.12597.619101356.110121920231741557191205779.23667.22611.219201363.21018193023295156529167.55809.33686.32624.819301370.310231940234161573392155839.43705.42638.419401377.41028195023537158169262.55869.53724.5265219501384.510341960236571589693105899.63743.62665.619601391.6103

33、9197023778159779357.55929.73762.72679.219701398.710441980238991605894055959.83781.82692.819801405.81049199024019161399453599038012706199014131055200024140162209500602038202720200014201060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kVA3155006308001000315+31512501600029174629477355536407583411096127

34、322028702514465854006210563810178115174028194388453052255980542392671033160276642544392530757305199842292608027124116424848415470497176668328100265639754102464352114746700375311202599383539554447495645286424685014025423697381042574711431859206268160248635633669407344794119548157691802429343335323897

35、426039315095533720023733307340037304054375547894994220231831873274357238633589448446592402264307331533424368434344190434126022112964303932843518329039524083280215928602930315333643155373838533002109276228273030322130293545364732020602669273029153088191133713406340202125802637280729642801321232933601

36、966249725502705284926983067314038019212417246726102741260129343000400187723422389252026402511281228724201835227123152436254624262700275444017952023224423562458234625962645460175521392178228123752271249925444801717207821142211229822002409245150016802021205421442225213323262364520164519651997208121562

37、070224822835401611191319432021209120212175220856015771683189219642030195421062137580154518151843191119721900204120706001514177017961860191718491981202162014841726175118111865180119241949640145516851708176518151755187018936601427164516681721176817111818184168014001607162916791724166917701791700137415

38、711591163916811629172417447201349153615561601164015911681169974013421503152115641602155516391657760130114711489152915651520159916167801278144014571495152914871562157880012551411142714631496145515261541820123413821398143214631424149214998401213135513701403143213951459147286011931329134313741402136714

39、271440880117313031317134713741339139714109001154127912921321134613131368138092011351255126812951320128813411352940111712331245127112941264131413259601100121112221248127012411288129998010831189120112251246121812641274100010671169118012031223119612401250105010271121113111511170114511841193110099110761

40、085110411211098113411421150957103510431060107610551087109412009259961004102010341015104410511250895961968983995978100410101300866928934948959943967973135084089790391592691193393814008158678738858958819019061450791840846856866852872876150076981582083083882684484815507477907958058138018178211600727768772781789778793797165070874675175976675577077317006907267307387447357487511750673707710718724715727730180065768869269970569670871118506416716746816866786896921900626654658664669661672674195061263964264865364565565720005986246276326