交直流导线截面的计算.doc

第一节 直流供电回路导线的截面计算根据允许压降计算选择直流供电回路导线的截面，一般有三种方法，即电流矩法、固定压降分配法和最小金属用量法（一）电流矩法电流矩法是以欧姆定律为依据，在直流供电回路中，某段导线通过最大电流I时，根据欧姆定律，该段导线上由于直流电阻造成的压降可按（公式5.1）计算：UIR=IL/SIL/（S） （公式5.1）对于单条分段线路，不论分段各点有无负荷，线路的导体总压降可按（公式5.3）计算：U总U1U2U3Un （公式5.2）公式5.2中：U总：单条分段线路导体总压降（V），是指从直流电源设备（如蓄电池、变换器等）的输出端子到用电设备（如变换器，通信设备等）的进线端子的最大允许压降中，扣除设备和元器件的实际压降后，所余下的那一部分；U1、U2、Un：导体第一段、第二段、第n段的压降（V）。将公式（5.3）按欧姆定律展开后，再进行等值变换，可以导出靠近直流电源设备的第一段导线的截面面积，根据计算结果选取导线截面后，再用同样的办法计算得出第二段、第三段第n段导线的截面面积。 对于有多条分支或同时兼有若干分流（负荷）点的线路，也可通过等值变换依次求得第一段、第二段第n段导线的截面面积。（二）固定分配压降法所谓固定分配压降法，就是把要计算的直流供电系统全程允许压降的数值，根据经验适当的分配到每个压降段落上去，从而计算各段落导线截面面积。如先后两段计算所得的导线截面显然不合理时，还应适当调整分配压降重新计算。根据以往的工程经验，这种方法可简化计算，只是精确性较差。48V直流供电系统电压降常用固定分配值如图5.1所示：采用固定分配压降法计算各段导线的步骤如下：u 确定各段导线的材质，一般情况下采用铜导线，也可根据需要采用铝导线；u 了解各段导线负荷和导线最大长度；u 分配各段导线上电压降数值；u 根据上述各条已知数据，按（公式5.2）计算出各段导线的截面积。（公式5.3）公式5.3中：计算段导体截面面积计算值（mm2）； ：计算段导体通过的最大电流（A）； ：计算段导线回路长度（m），如已知单程长度时，应乘以2；：计算段导体的电导率（m/mm2），铜57，铝34； ：计算段导体的电压降。u 检验上一步骤计算得出的相邻两段的导线截面是否合理，如显然不合理时，还应适当调整分配压降重新计算；u 根据上述步骤计算出的计算段导体截面积数值的大小及导线的敷设方式、安装要求等，根据表5-1至表5-4选出适用导线的型号及规格。铜线截面计算表（电流矩） 表5-1截面(mm2)11.52.546101625压降U(v)电流矩(Am)0.010.570.851.422.283.425.79.114.20.021.141.712.854.566.8411.418.228.50.031.712.564.276.8410.2617.127.342.70.042.283.425.79.1213.722.836.5570.052.854.277.1211.417.128.545.6710.063.425.138.5513.720.534.256.7850.073.995.989.9715.92439.963.8990.084.566.8411.418.227.445.6731140.095.137.6912.820.530.851.3821280.15.78.5514.222.834.257911420.126.810.21727.441681091700.14811.919.83248791271990.169.113.722.736.655911452270.1810.215.425.641621021642560.211.417.128.545.6681141822850.2212.518.831.350751252003130.2413.720.534.254821362183420.2614.822.23759891482383710.281623.939.964901592543990.317.125.642.7681031712734270.3218.227.345.5731091822914550.3419.42948.3771161933094840.3620.530.751.2821232053275130.3821.632.454.1871302163465410.422.834.257971372283655700.4223.935.959.8951442393835980.4425.137.662.71001512504016270.4626.239.365.51041582624196550.4827.44168.41091652734326840.528.542.771.21141712854567120.5229.644.4741181782964747400.5430.846.176.91231853074927690.5631.947.879.71281923195107970.583349.582.61321993305288250.634.251.385.51372053425478550.6235.35388.31412123535658830.6436.554.791.21462193645839120.6637.656.494.11512263756019400.6838.758.196.81552333876199690.739.959.899.71592403996389970.724161.5102.516324741065610250.7442.163.2105.416825442167410540.7643.264.9108.217226143369210720.7844.466.7111.117426844471111110.845.668.411418227445673011400.951.376.9128205308513820128215785.514222834257091214251.268102170273410684109417101.480119199319478798127619951.691137227364547912145822801.810215425641261610261690256521141712854566841140182428502.21251883135017521254200631352.41362053425478201368218834202.61472223705928891482237037052.8159239399638957159625523990317125642768410261710273642753.218327345572910941824291845603.41942904837751631938310148453.620830751282112312052328851303.8217324841866130021543465521542283425709121368223036485700铜线截面计算表（电流矩） 续表5-1截面(mm2)35507095120150185240压降U(v)电流矩(Am)0.012028.5405468851051360.024057801081371712112730.0360851201622052563164100.04801141602162733424225470.051001422002703424275276640.061201712403254105136328210.071401992803794785987389580.0816022832043354768484310940.0918025636048761576994912340.1200285399541684855105413680.122403424796498211026126516410.142803995597579581197147619150.1632045663986510951368168721880.1836051371997312321539189824620.2399570798108313681710210927360.22439621878119115051881232030090.24479684953129916422052253132830.265197411038140717792223274235560.285597981118151519162394295338300.35998551197162320522565316341040.326399121277173121892736337443770.346799691357183923262907358546510.3671910261437194724633078379649250.3875910831517205526003249400751990.479811401596216527363420421854720.4283811971676227328733591442957450.4487812541756238130103762464060190.4691813111836248931473933485162920.4895813681916259732844104506265660.599814251995270734204275527268400.52103814822075281535574446548371130.54107815392155292336944617569473870.56111815962235303138314788590576600.58115816532315313939684959611679340.6119717102394324941045130632782080.62123717622474305742415301653884810.64127718242554346543785472674987550.66131718812634357245155643696090280.68135719382713368146525814717193090.7139719952793379047885985738195760.72143720522873389849256156759298490.741477210929534006506263277803101260.761517216630334114519964988014104000.781557222331134222533666698225106730.81596228031924332547268408436109440.9179625653591487361567698949012342119952850399054156840855010545136801.2239434204788649882081026012654164161.4279339905586758095761197014762191521.6319245606384866410954136801687221888铜母线截面计算表（电流矩法） 表5-2截面(mm2)404160405200505250 506.3315636.3396.9638806.3504压降U(v)电流矩(Am)0.01911141431802262870.021822282853594525750.032743424285396798620.0436545657071890511490.05456570713898113114360.065476848551077135717240.076387989981257158420110.0873091211401436181022980.09821102612831616203625860.1912114014251796226228730.121094136817102155271534470.141277159619952514316740220.161459182422802873362045960.181642205225653232407251710.21824228028503591452557460.222006250831353950497763200.242189273634204309543068950.262371296437054668588274690.282554319239905027633580440.32736342042755387678786180.322918364845605746723991930.343101387648456105769297680.3632834104513064648144103420.3834664332541568238597109170.436484560570071829049114910.4238304788598575419502120660.4440135016627079009954126400.46419552446555825910407132150.48437854726840861810859137890.5456057007125897811312143640.52474259287410933711764149390.54492561567695969612217155130.565107638479801005512669160880.585290661282651041413122166620.65472684085501077313574172370.625654706888351113214026178110.645837729691201149114479183860.666019752494051185014931189600.686202775296901220915384195350.76384798099751256915836201100.7265668208102601292816289206840.7467498436105451328716741212590.7669318664108301364617194218330.7871148892111151400517646224080.872968120114001436418099229820.8274789348116851472318551235570.8476619576119701508219004241320.8678439804122551544119456247060.88802610032125401580019909252810.9820810260128251616020361258550.92839010488131101651920813264300.94857310716133951687821266270040.96875510944136801723721718275790.98893811172139651759622171281531912011400142501795522623287281.05957611970149621885323754301641.1100321540156751975124886316011.151048813110163882064826017330371.21094413680171002154627148344741.251140014250178132274428279359101.31185614820185252334229410373461.351231215390192382423930541387831.41276815960199502513731673402191.451322416530206632603532804416561.51368017100213752693333935430921.551413617670220882783035066445281.61459218240228002872836197459651.651504818810235132962637328474011.71550419380242253052438460488381.751596019950249383142139591502741.8164162052025650323194072251710铜母线截面计算表（电流矩法） 续表5-2截面(mm2)80864010088010800100108012.51258100010012.512510125011212.51400压降U(v)电流矩(Am)0.013654565707137980.027309121140142515960.03109413681710213823940.04145918242280285031920.05182422802850356339900.06218927363420427547880.07255431923990498855860.08291836484560570063840.09328341045130641271820.1364845605700712579800.12437854726840855095760.145107638479809975111720.165837796912011400127680.18656682081026012825143640.2729691201140014250159600.228026100321254015675175560.248755109441368017100191520.269485118561482018525207480.2810214127681596019950223440.310944136801710021375239400.3211674145921824022800255360.3412403155041938024225271320.3613133164162052025650287280.3813862173282166027075303240.414592182402280028500319200.4215322191522394029925335160.4416051200642508031350351120.4616781209762622032775367080.4817510218882736034200383040.518240228002850035625399000.5218970237122964037050414960.5419699246243078038475430920.5620429255363192039900446880.5821158264483306041325462840.621888273603420042750478800.6222618282723534044175494760.6423347291843648045600510720.6624077300963762047025526680.6824806310083876048450542640.725536319203990049875558600.7226266328324104051300574560.7426995337444218052725590520.7627725346564332054150606480.7828454355684446055575622440.829184364804560057000638400.8229914373924674058425654360.8430643383044788059850670320.8631373392164902061275686280.8832102401285016062700702240.932832410405130064125718200.9233562419525244065550734160.9434291428645358066975750120.9635021437765472068400766080.983575044688558606982578204136480456005700071250798001.0538304478805985074813837901.140128501606270078375877801.1541952524406555081938917701.243776547206840085500957601.2545600570007125089063997501.3474245928074100926251037401.35492486156076950961881077301.4510726384079800997501117201.455289666120826501033131157101.55472068400855001068751197001.555654470680883501104381236901.65836872960912001140001276801.656019275240940501175631316701.76201677520969001211251356601.756384079800997501246881396501.86566482080102600128250143640铝线截面计算表（电流矩法） 表5-3截面(mm2)2.5461016253550压降U(v)电流矩(Am)0.010.851.362.043.45.448.511.9170.021.72.724.086.810.881723.8340.032.554.086.1210.216.3225.535.7510.043.45.448.1613.621.763447.6680.054.256.810.21727.242.559.5850.065.18.1612.2420.432.645171.41020.075.959.5214.2823.838.0859.583.31190.086.810.8816.3227.243.526895.21360.097.6512.2418.3630.648.9676.51071530.18.513.620.43454.4851191700.1210.216.324.540.865.31021432040.1411.919.128.647.6176.21191672380.1613.621.832.654.4871361902720.1815.324.536.761.297.91532143060.21727.240.8681091702383400.2218.729.944.974.81201872623740.2420.432.64981.61312042854080.2622.135.45388.41412213094420.2823.838.157.195.21522383334760.325.540.861.21021632553575100.3227.243.565.31071742723815440.3428.946.269.41161852894055780.3630.64973.41221963064286120.3832.351.777.51292073234526460.43454.481.61362183404766800.4235.757.185.71432283575007140.4437.459.898.81502393745247480.4639.162.693.81562503915477820.4840.865.397.91632614085718160.542.5681021702724255958500.5244.270.71061772834426198840.5445.973.41101842944596439180.5647.676.21141903054766669520.5849.378.91181972164936909860.65181.612220432651071410200.6252.784.312721133752773810540.6454.48713121834854476210880.6656.189.813522435956178511220.6857.892.513923137057880911560.759.595.214323838159588311900.7261.297.9214724539261285712240.7462.910115125240362988112580.7664.610315525841364690412920.7866.3106159265424663292813260.86810916327243568095213600.976.512218430648976510711530185136204340544850119017001.21021632454086341020142820401.41191902864767621190166623801.61362183265448701360190427201.8153245367612979153021423060217027240868010881700238034002.218729944974811971870261837402.420432649081613062040285640802.622125453088414142210309444202.823828157195215232380333247003255408612102016322550357051003.2272435653106817412720380854403.4289462694115618502890404657803.6306490734122419583060428461203.832351777512922067323045226460434054481613602176340047606800铝线截面计算表（电流矩法） 续表5-3截面(mm2)7095120150185240300400压降U(v)电流矩(Am)0.0123.832.840.85162.981.61021360.0247.664.681.6102125.81632042720.0371.496.9122.41531892453064080.04951291632042523264085440.051191622042553154085106800.061431942453063774896128160.071672262863574405717149520.0819025832640850365381610880.0921429136745956673491812240.1238323408510629815102013600.12296388490612755979122416320.143334525717148811142142819040.1638151765381610061306163221760.1842858173491811321469183624480.2476646816102012581632204027200.22524711898112213841795224429920.24571775979122415101958244832640.266198401061132616352122265235360.286669041142142817612285285638080.37149691224153018872448306040800.3276210341306163220132611326443520.3480910981387173421392774646846240.3685711631469183622642938367248960.3890412271550193823903101387651680.495212921632204025163264408054400.42100013571714214226423427428457120.44104714211795224427683590448859840.46109514861877234628933754469262560.4811421550195824483019391748966