两相短路电流计算及查表.doc
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两相短路电流计算及查表.doc

两相短路电流计算及查表.doc

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两相短路电流计算及查表优质资料(可以直接使用,可编辑优质资料,欢迎下载)解析法计算低压电网短路电流计算两相短路电流的计算公式为:I==R1/Kb2+Rb+R2=Xx+X1/Kb2+Xb+X2式中:I—两相短路电流,A;、—短路回路内一相电阻、电抗值的总和,Ω;Xx—根据三相短路容量计算的系统电抗值,Ω;R1、X1—高压电缆的电阻、电抗值,Ω;Kb—矿用变压器的变压比,若一次电压为6000V,二次电压为400、690、1200V时,变比依次为15、8.7、5;当一次电压为10000V,二次电压为400、690、1200V时,变比依次为25、14.5、8.3;Rb、Xb—矿用变压器的电阻、电抗值,Ω;R2、X2—低压电缆的电阻、电抗值,Ω;Ue—变压器二次侧的额定电压,V。若计算三相短路电流值I=1.15I矿用橡套电缆的单位长度电阻与电抗阻抗Z0(Ω/km)截面(mm2)4610162535507095120电阻R05.53.6932.1591.3690.86380.61600.44840.31510.23010.18电抗X00.1010.0950.0920.0900.0880.0840.0810.0780.0750.074380V、660V、1140V系统各电缆的换算系数为下表电缆截面4610162535507095换算系数11.978.114.753.011.911.371.000.730.53127V系统各电缆的换算系数为下表电缆截面2.54610换算系数1.641.000.580.34KBSG型变压器二次侧电压690V两相短路电流计算表(2)电缆换算长度(m)变压器容量(kVA)501002003154005006308001000090518123625569972449065912910576120852089517743484536867128225832594941068740884173633334999611772967402826491076087416963177462655346430652871467725808631656302142715001568157666211661510085316162870394345315052512454515741120842157527253646412345284589483450491408321535258833803771409141424331449416082114962459314334663724376739154043180810145723392933322534123449356836702008001419222727452972314531773275335722078913822123257727702916294330243092240779134720272426259227162740280728652607691312193722912435254025622619266828075812781854216922942386240424542496300718124617772058216922482265230823443207381214170519582055212521402178221034072811841638186619532021202820512089360719115515761782186019151927195719813807091126151817051775182518361862188440070010991464163516981742175217761796420690107314131569162716671676169717154406811048136515091561159716061625164146067210241321145315001533154115591574480663100012781400144414741482149815115006549781239135213921420142714411454520646956120113061343136913751389140054063793611661264129813221328134013515606299151133122412561277128312951304580621896110111861216123612411252126160061387810711151117811971202121212216206058601043111711431161116611751183640597842101610861110112711