查表法求取煤礦井下低壓電網(wǎng)兩相短路電流

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1（2^:校驗短路保護的靈敏系數(shù)。?計算最大三相短路電流【⑶：校驗斷路器的切斷能力。max?同一短路點：八、■- ,、，I⑶=1.151⑵1備號留=0.8661*婦婦?換算長度?換算原則：電纜換算前后阻抗不變。?煤礦井下低壓各種截面積的動力電纜，其長度為L、截面為A，均換算成截面積為50mm2的電纜，查表求取兩相短路電流［⑵。換算長度為minL疽七L⑴IQ電纜的換算長度，即把實際長度換算成標準截面為50mm2的長度m;L--電纜的實際長度，m;keq-換算系數(shù)。見表1、表2.換算原則:換算前后阻抗相等。即（（rL》+GL》=k'C*L）+，L）C+X2\=C+土L2+x2k=—eq=Y,0―0-eqL..■r2+x2V50 50表1煤礦井下1140V、660V、380V低壓電纜換算系數(shù)（kq）額定電壓等級U、（V）N380、660、1140電纜截面A（mm2）4610162535507095換算系數(shù)keq12.078.114.753.011.911.361.000.710.53*摘自《礦山電工學》（修訂本）賴昌干，煤炭工業(yè)出版社，2012年3月第1版，P58，表2-8的步驟?查表法計算煤礦井下兩相短路電流1（2）的步驟min?在供電系統(tǒng)圖中選定短路計算點;

卜利用公式（1）計算短路點至變壓器二次側(cè)各段電纜的換算長度Leq?計算總換算長度T 。即%eq2eq=Leqs+keq-gLeq?g 卜利用公式（1）計算短路點至變壓器二次側(cè)各段電纜的換算長度Leq?計算總換算長度T 。即%eq2eq=Leqs+keq-gLeq?g Leq?i=1(2)Ly-短路點至電源的全部電纜總換算長度,m;Leq."電源系統(tǒng)電抗的換算長度,m（查表3）keqg-高壓電纜（6kV,10kV）換算系數(shù)（查表4,表5）；｛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：R=rLX=xL1 01' 1 01r0,x0為高壓電纜每千米長的電阻、電抗值，Qkm。勺高壓電纜的計算長度，km折算至低壓側(cè)，的阻抗為:=r0L(TJ、2X'=Xr1kU17L[u

kU27截面為50mm2的阻抗為七=r/，X<n=\L50 50eq50 50eq折算系數(shù)keq.g為:、.(R：\+(X:}=-R+x50rL0U

kU17X0LU

kU17rL)+50eq:L50eqkeq■r2+x2、2\r2+x2Lg一高壓電纜實際上長度,m;Leq.i-變壓器二次側(cè)各段電纜換算長度m.A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誨

隔爆型移動變電站干式變壓器技術參數(shù)：短路損耗AP、短路電壓百分數(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（L約.\）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》（修訂本）賴昌干，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)電纜長度的換算系數(shù)（七"電纜芯線材料銅芯（10kV銅芯電纜,換算至50mm2對應電壓等級下的換算系數(shù)）額定電壓（V）38066011403300礦用10kV銅芯電纜,截面積（mm2）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時礦用電纜不同芯線截面的換算長度（m）電纜截面（mm2）4610162535507095'換算系數(shù)電纜實際、長度（m） 、12.078.114.753.011.911.361.000.710.53101218114830191410752024116295603827201411303622431439057413021164048332419012076544028215060440623815196685036276072448728518111582604332708455683332111349570503780966649380241153109805742901086730428271172122906448100120781147530119113610071531101328892523331210150110785812014489735703612291631208564

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560675945422660168610707625603982975706880462327081716108977557040530258070014704275517461108789580412307590712147852803177611278025904193136007242486628501806114681660042631861073634947289818361165830610433323620748350282945186611848436204403296307604510929931896120385763044733464077255190304019261222870640454339650784652723088195712428846504623456607966535331351987126189866046935067080875434318320171280911670476355680820855153230204712999256804833606908328559632782077131893869049036670084495677332521071337952700497371710857057583373213713569667105043767208690583934202167137597972051138273088115920346821971394993730518387740893260013515222714131006740525392750905360833563225814331020750533398760917361643610228814521034760540403770929462453658231814711047770548408780941563263705234814901061780554413790953564073753237815091074790561419800965664883800240815281088800568424810977765693848243815471102810575429820989766503895246815661115820582435830100186731394324981585112983058944084010139681239902528160411428405964458501026068944037.52559162411568506044518601038069754085258916431170860611456870105017056413326191662118387061846188010622713741802649168111978806254668901074272184228267917001210890632472900108637299427527091719122490063947791010984738043232739173812389106464829201110474614370276917571251920653488930112257542441827991776126593066049394011346762344652829179512789406674989501146777054513286018151292950675504960115877786456028901834130696068250997011708786746082920185313199706895149801182979484655295018721333980696520

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1420171391151667454274.22712.21931.214201008.2753143017260115976792.54304.32731.31944.814301015.37581440173811167868404334.42750.41958.414401022.4763145017502117606887.54364.52769.5197214501029.57691460176221184169354394.62788.61985.614601036.6774147017743119226982.54424.72807.71999.214701043.77791480178641200370304454.82826.82012.814801050.8784149017984120847077.54484.92845.92026.414901057.979015001810512165712545152865204015001065795151018226122467172.54545.12884.12053.615101072.18001520183461232772204575.22903.22067.215201079.2806153018467124087267.54605.32922.32080.815301086.38111540185881248973154635.42941.42094.415401093.4816155018709125717362.54665.52960.5210815501100.58221560188291265274104695.62979.62121.615601107.6827157018950127337457.54725.72998.72135.215701114.78321580190711281475054755.83017.82148.815801121.8837159019191128957552.54785.93036.92162.415901128.984316001931212976760048163056217616001136848161019433130577647.54846.13075.12189.616101143.18531620195531313876954876.23094.22203.216201150.2859163019674132197742.54906.33113.32216.816301157.38641640197951330077904936.43132.42230.416401164.4869165019916133827837.54966.53151.5224416501171.58751660200361346378854996.63170.62257.616601178.6880167020157135447932.55026.73189.72271.216701185.78851680202781362579805056.83208.82284.816801192.8890169020398137068027.55086.93227.92298.416901199.9896170020519137878075511732472312170012079011720207601394981705177.23285.22339.217201221.2912173020881140308217.55207.33304.32352.817301228.39171740210021411182655237.43323.42366.417401235.4922175021123141938312.55267.53342.5238017501242.59281760212431427483605297.63361.62393.617601249.6933177021364143558407.55327.73380.72407.217701256.79381780214851443684555357.83399.82420.817801263.8943179021605145178502.55387.93418.92434.417901270.994918002172614598855054183438244818001278954181021847146798597.55448.13457.12461.618101285.19591820219671476086455478.23476.22475.218201292.2965183022088148418692.55508.33495.32488.818301299.39701840222091492287405538.43514.42502.418401306.4975185022330150048787.55568.53533.5251618501313.5981

1860224501508588355598.63552.62529.618601320.6986187022571151668882.55628.73571.72543.218701327.79911880226921524789305658.83590.82556.818801334.8996189022812153288977.55688.93609.92570.418901341.91002190022933154099025571936292584190013491007191023054154909072.55749.13648.12597.619101356.110121920231741557191205779.23667.22611.219201363.21018193023295156529167.55809.33686.32624.819301370.310231940234161573392155839.43705.42638.419401377.41028195023537158169262.55869.53724.5265219501384.510341960236571589693105899.63743.62665.619601391.61039197023778159779357.55929.73762.72679.219701398.710441980238991605894055959.83781.82692.819801405.81049199024019161399453599038012706199014131055200024140162209500602038202720200014201060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（kVA）3155006308001000315+3151250160002917462947735553640758341109612732202870251446585400621056381017811517402819438845305225598054239267103316027664254439253075730519984229260

80271241164248484154704971766683281002656397541024643521147467003753112025993835395544474956452864246850140254236973810425747114318592062681602486356336694073447941195481576918024293433353238974260393150955337200237333073400373040543755478949942202318318732743572386335894484465924022643073315334243684343441904341260221129643039328435183290395240832802159286029303153336431553738385330021092762282730303221302935453647320206026692730291530881911337134063402012258026372807296428013212329336019662497255027052849269830673140380192124172467261027412601293430004001877234223892520264025112812287242018352271231524362546242627002754440179520232244235624582346259626454601755213921782281237522712499254448017172078211422112298220024092451500168020202054214422252133232623645201645196519972081215620702248228354016111913194320212091201021752208560157716831892196420301954210621375801545181518431911197219002041207060015141770179618601917184919812008620148417261751181118651801192419496401455168517081765181517551870189366014271645166817211768171118181841680140016071629167917241669177017917001374157115911639168116291724174472013491536155616011640159116811699740134215031521156416021555163916577601301147114891529156515201599161678012781440145714951529148715621578800125514111427146314961455152615418201234138213981432146314241492149984012131355137014031432139514591472860119313291343137414021367142714408801173130313171347137413391397141090011541279129213211346131313681380

9201135125512681295132012881341135294011171233124512711294126413141325960110012111222124812701241128812999801083118912011225124612181264127410001067116911801203122311961240125010501027112111311151117011451184119311009911076108511041121109811341142115095710351043106010761055108710941200925996100410201034101510441051125089596196898399597810041010130086692893494895994396797313508408979039159269119339381400815867873885895881901906145079184084685686685287287615007698158208308388268448481550747790795805813801817821160072776877278178977879379716507087467517597667557707731700690726730738744735748751175067370771071872471572773018006576886926997056967087111850641671674681686678689692190062665465866466966167267419506126396426486536456556572000598624627632637630639641表9KSGZY型移動變電站二次額定電壓為690V系統(tǒng)兩相短路電流（A）電纜換算長度（m）變壓器容量（kV.A）100200315500630200+200800100001597319450327979823963891262613852201567308347717334758059301016910903401537296544836612682554418318877160150528434189591960934969696472618014732721390452995440453559586164100144226013637476348774147519253411201410248433904305439838054592470514013782373316539163992350541134200160134722672961358436473243372137911801316216727783299335230133397345320012852073261230523097281031393186220125619852462283828762630290329422401227190323262650268324702688272226011981825220424842513232825132542

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