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 l计算短路电流的目的计算两相短路电流:校验短路保护的灵敏系数。计算最大三相短路电流:校验断路器的切断能力。同一短路点：， l换算长度换算原则：电缆换算前后阻抗不变。煤矿井下低压各种截面积的动力电缆，其长度为L、截面为A，均换算成截面积为50的电缆，查表求取两相短路电流。换算长度为 （1）-电缆的换算长度，即把实际长度换算成标准截面为50的长度m;L-电缆的实际长度，m;-换算系数。见表1、表2.换算原则:换算前后阻抗相等。即 表1 煤矿井下1140V、660V、380V低压电缆换算系数（）额定电压等级（V)380、660、1140电缆截面A（)46101

2、62535507095换算系数 12.07 8.114.75 3.01 1.91 1.36 1.00 0.71 0.53*摘自矿山电工学（修订本）赖昌干，煤炭工业出版社，2012年3月第1版，P58，表2-8l查表法计算煤矿井下两相短路电流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计算总换算长度。即 （2）-短路点至电源的全部电缆总换算长度,m;-电源系统电抗的换算长度,m（查表3）;-高压电缆（6k，10kV）换算系数（查表4，表5）；高压电缆折算至低压侧的原则：阻抗相等折算前的阻抗为：,，为高压电缆每千米长的电阻、电抗值，。高压电缆的计算长

3、度，km折算至低压侧,的阻抗为：截面为50的阻抗为,折算系数为: -高压电缆实际上长度,m;-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、短路电压百分数，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（）系统容量（MV.A） 25 30 4050100额定电压（V)400 14.111.78.87.03.5166041.

4、834.926.120.910.461140126.5105.479.163.331.63*摘自矿山电工学（修订本）赖昌干，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（）电缆芯线材料铜芯（10kV铜芯电缆,换算至50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（）160.00420.01260.03750.3144250.00270.00810.02410.2017350.00190.00580.01730.1447500.00140.00410.01220.1022700

5、.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(mm)4610162535507095 换算系数电缆实际长度(m)12.07 8.114.75 3.01 1.91 1.36 1.00 0.71 0.5310121811483019141075202411629560382720141130362243143905741302116404833241901

6、207654402821506044062381519668503627607244872851811158260433270845568333211134957050378096664938024115310980574290108673042827117212290644810012078114753011911361007153110132889252333121015011078581201448973570361229163120856413015691054618391248177130926914016901135665421267190140997415018111217713

7、452287204150107801601931129876048230621816011485170205213798085123252311701219018021731460855542344245180128951902293154190357236325819013510120024141622950602382272200142106210253517035998632840182862101491112202655178410456624202992201561172302776186510936924393132301631222402897194611407224583262

8、40170127250301820281187.575347834025017813326031382109123578349735426018513827032592190128381351636727019214328033802271133084353538128019914829035002352137887355439429020615430036212433142590357340830021315931037422514147393359242231022016432038622595152096361143532022717033039832676156899363044933

9、023417534041042757161510236494623402411803504225283916631054669476350249186360434529201710108468849036025619137044663001175811147075033702631963804587308218051144726517380270201390470731631853117474553039027720740048283244190012047645444002842124104949332519481234783558410291217420506934061995126480

10、257142029822343051903487204312948215854303052284405311356820901324840598440312233450543236502138135586061245032023946055523731218513858796264603272444705673381222331415898639470334249480579438932280144591765348034125449059143974232814759366664903482605006035405523751505955680500355265510615641362423

11、153597469451036227052062764217247015659937075203692765306397429825181595101272153037628154065184379256516251031734540383286550663944612613165610517485503912925606759454226601686107076256039829757068804623270817161089775570405302580700147042755174611087895804123075907121478528031776112780259041931360

12、072424866285018061146816600426318610736349472898183611658306104333236207483502829451866118484362044032963076045109299318961203857630447334640772551903040192612228706404543396507846527230881957124288465046234566079665353313519871261898660469350670808754343183201712809116704763556808208551532302047129

13、992568048336069083285596327820771318938690490366700844956773325210713379527004973717108570575833732137135696671050437672086905839342021671375979720511382730881159203468219713949937305183877408932600135152227141310067405253927509053608335632258143310207505333987609173616436102288145210347605404037709

14、294624536582318147110477705484087809415632637052348149010617805544137909535640737532378150910747905614198009656648838002408152810888005684248109777656938482438154711028105754298209897665038952468156611158205824358301001867313943249815851129830589440840101396812399025281604114284059644585010260689440

15、37.525591624115685060445186010380697540852589164311708606114568701050170564133261916621183870618461880106227137418026491681119788062546689010742721842282679170012108906324729001086372994275270917191224900639477910109847380432327391738123891064648292011104746143702769175712519206534889301122575424418

16、279917761265930660493940113467623446528291795127894066749895011467770545132860181512929506755049601158777864560289018341306960682509970117087867460829201853131997068951498011829794846552950187213339806965209901194980294703298018911346990703525100012070811047503010191013601000710530101012191819147983

17、040192913741010717535102012311827248453070194813871020724541103012432835348933100196714011030731546104012553843449403130198614141040738551105012674851649883161200614281050746557106012794859750353191202514412106075356210701291586785083322120441455107076056710801303687595130325120631469108076757210901

18、315688405178328120821482109077457811001327789215225331121011496110078158311101339890025272.53341.12120.11509.61110788.1588112013518908353203371.22139.21523.21120795.259411301363991645367.53401.32158.31536.81130802.3599114013760924554153431.42177.41550.41140809.460411501388193275462.53461.52196.51564

19、1150816.5610116014001940855103491.62215.61577.61160823.661511701412294895557.53521.72234.71591.21170830.7620118014243957056053551.82253.81604.81180837.862511901436396515652.53581.92272.91618.41190844.963112001448497325700361222921632120085263612101460598135747.53642.12311.11645.61210859.164112201472

20、5989457953672.22330.21659.21220866.264712301484699755842.53702.32349.31672.81230873.36521240149671005658903732.42368.41686.41240880.4657125015088101385937.53762.52387.517001250887.56631260152081021959853792.62406.61713.61260894.6668127015329103006032.53822.72425.71727.21270901.7673128015450103816080

21、3852.82444.81740.81280908.8678129015570104626127.53882.92463.91754.41290915.96841300156911054361753913248317681300923689131015812106246222.53943.12502.11781.61310930.16941320159321070562703973.22521.21795.21320937.2700133016053107866317.54003.32540.31808.81330944.37051340161741086763654033.42559.418

22、22.41340951.4710135016295109496412.54063.52578.518361350958.57161360164151103064604093.62597.61849.61360965.6721137016536111116507.54123.72616.71863.21370972.77261380166571119265554153.82635.81876.81380979.8731139016777112736602.54183.92654.91890.41390986.97371400168981135466504214267419041400994742

23、141017019114356697.54244.12693.11917.614101001.17471420171391151667454274.22712.21931.214201008.2753143017260115976792.54304.32731.31944.814301015.37581440173811167868404334.42750.41958.414401022.4763145017502117606887.54364.52769.5197214501029.57691460176221184169354394.62788.61985.614601036.677414

24、7017743119226982.54424.72807.71999.214701043.77791480178641200370304454.82826.82012.814801050.8784149017984120847077.54484.92845.92026.414901057.979015001810512165712545152865204015001065795151018226122467172.54545.12884.12053.615101072.18001520183461232772204575.22903.22067.215201079.28061530184671

25、24087267.54605.32922.32080.815301086.38111540185881248973154635.42941.42094.415401093.4816155018709125717362.54665.52960.5210815501100.58221560188291265274104695.62979.62121.615601107.6827157018950127337457.54725.72998.72135.215701114.78321580190711281475054755.83017.82148.815801121.8837159019191128

26、957552.54785.93036.92162.415901128.984316001931212976760048163056217616001136848161019433130577647.54846.13075.12189.616101143.18531620195531313876954876.23094.22203.216201150.2859163019674132197742.54906.33113.32216.816301157.38641640197951330077904936.43132.42230.416401164.4869165019916133827837.5

27、4966.53151.5224416501171.58751660200361346378854996.63170.62257.616601178.6880167020157135447932.55026.73189.72271.216701185.78851680202781362579805056.83208.82284.816801192.8890169020398137068027.55086.93227.92298.416901199.9896170020519137878075511732472312170012079011720207601394981705177.23285.2

28、2339.217201221.2912173020881140308217.55207.33304.32352.817301228.39171740210021411182655237.43323.42366.417401235.4922175021123141938312.55267.53342.5238017501242.59281760212431427483605297.63361.62393.617601249.6933177021364143558407.55327.73380.72407.217701256.79381780214851443684555357.83399.824

29、20.817801263.8943179021605145178502.55387.93418.92434.417901270.994918002172614598855054183438244818001278954181021847146798597.55448.13457.12461.618101285.19591820219671476086455478.23476.22475.218201292.2965183022088148418692.55508.33495.32488.818301299.39701840222091492287405538.43514.42502.41840

30、1306.4975185022330150048787.55568.53533.5251618501313.59811860224501508588355598.63552.62529.618601320.6986187022571151668882.55628.73571.72543.218701327.79911880226921524789305658.83590.82556.818801334.8996189022812153288977.55688.93609.92570.418901341.9100219002293315409902557193629258419001349100

31、7191023054154909072.55749.13648.12597.619101356.110121920231741557191205779.23667.22611.219201363.21018193023295156529167.55809.33686.32624.819301370.310231940234161573392155839.43705.42638.419401377.41028195023537158169262.55869.53724.5265219501384.510341960236571589693105899.63743.62665.619601391.

32、61039197023778159779357.55929.73762.72679.219701398.710441980238991605894055959.83781.82692.819801405.81049199024019161399453599038012706199014131055200024140162209500602038202720200014201060表8 KSGZY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+315125016000291746294773555364075

33、834110961273220 287025144658540062105638101781151740281943884530522559805423926710331602766425443925307573051998422926080271241164248484154704971766683281002656397541024643521147467003753112025993835395544474956452864246850140 2542369738104257471143185920626816024863563366940734479411954815769180242

34、934333532389742603931509553372002373330734003730405437554789499422023183187327435723863358944844659240226430733153342436843434419043412602211296430393284351832903952408328021592860293031533364315537383853300210927622827303032213029354536473202060266927302915308819113371340634020122580263728072964280

35、132123293360196624972550270528492698306731403801921241724672610274126012934300040018772342238925202640251128122872420183522712315243625462426270027544401795202322442356245823462596264546017552139217822812375227124992544480171720782114221122982200240924515001680202020542144222521332326236452016451965

36、199720812156207022482283540161119131943202120912010217522085601577168318921964203019542106213758015451815184319111972190020412070600151417701796186019171849198120086201484172617511811186518011924194964014551685170817651815175518701893660142716451668172117681711181818416801400160716291679172416691770

37、17917001374157115911639168116291724174472013491536155616011640159116811699740 13421503152115641602 1555163916577601301147114891529156515201599161678012781440145714951529148715621578800125514111427146314961455 15261541820123413821398143214631424 14921499840121313551370140314321395 1459147286011931329

38、1343137414021367 1427144088011731303131713471374133913971410900115412791292132113461313 13681380920113512551268129513201288 13411352940111712331245127112941264 13141325960110012111222124812701241 12881299980108311891201122512461218126412741000106711691180120312231196124012501050102711211131115111701

39、145118411931100991107610851104112110981134114211509571035104310601076105510871094120092599610041020103410151044105112508959619689839959781004101013008669289349489599439679731350840897903915926911933938140081586787388589588190190614507918408468568668528728761500769815820830838826844848155074779079580

40、5813801 817821160072776877278178977879379716507087467517597667557707731700690726730738744735748751175067370771071872471572773018006576886926997056967087111850641671674681686678689692190062665465866466966167267419506126396426486536456556572000598624627632637630639641表9 KSGZY型移动变电站二次额定电压为690V系统两相短路电流（A）电缆换算长度(m)变压器容量（kV.A）100200315500630200+200800100001597319450327979823963891262613