标幺值法计算书

'标幺值法计算书1.简图已知条件元件1--电力系统:基准容量Sj=100MVA系统短路容量Ss"=500MVA标幺值X1=Sj/Ss"=100MVA/500MVA=0.200元件2--线路:基准容量Sj=100MVA线路长度L=1kM平均额定电压Uj=10.5kV单位阻抗X0=0.08Ω/km标幺值X2=X0LSj/Uj2=0.08Ω/km*1km*100MVA/10.5kV2=0.073元件3--变压器(双绕组):基准容量Sj=100MVA额定容量Sr=1600KVA短路电压Ud%=6标幺值X3=Uk%Sj/100Sr=6*100MVA/100*1600KVA=3.750 2.计算公式和过程短路点1基准电压Uj=10.5kV基准容量Sj=100MVA冲击系数Kch=1.8短路电抗Xjs=X1=0.200短路容量Sd=Sj/Xjs=100/0.200=500.000MVA三相短路电流有效值Id(3)=Ij/Xjs=5.499/0.200=27.493kA三相短路冲击电流ic(3)=1.414KchId(3)=1.414*1.8*27.493kA=69.986kA三相短路电流全电流有效值Ic(3)=[1+2(Kch-1)2]0.5Id(3)=[1+2(1.8-1)2]0.5*27.493kA=41.514kA两相短路冲击电流ic(2)=0.866ic(3)=0.866*69.986kA=60.608kA两相短路电流有效值Id(2)=0.866Id(3)=0.866*27.493kA=23.809kA两相短路电流全电流有效值Ic(2)=0.866Ic(3)=0.866*41.514kA=35.951kA短路点2基准电压Uj=10.5kV基准容量Sj=100MVA冲击系数Kch=1.8短路电抗Xjs=X1+X2=0.200+0.073=0.273短路容量Sd=Sj/Xjs=100/0.273=366.300MVA三相短路电流有效值Id(3)=Ij/Xjs=5.499/0.273=20.141kA三相短路冲击电流ic(3)=1.414KchId(3)=1.414*1.8*20.141kA=51.271kA三相短路电流全电流有效值Ic(3)=[1+2(Kch-1)2]0.5Id(3)=[1+2(1.8-1)2]0.5*20.141kA=30.412kA两相短路冲击电流ic(2)=0.866ic(3)=0.866*51.271kA=44.401kA两相短路电流有效值Id(2)=0.866Id(3)=0.866*20.141kA=17.442kA两相短路电流全电流有效值Ic(2)=0.866Ic(3)=0.866*30.412kA=26.337kA短路点3基准电压Uj=0.4kV基准容量Sj=100MVA冲击系数Kch=1.8短路电抗Xjs=X1+X2+X3=0.200+0.073+3.750=4.023 短路容量Sd=Sj/Xjs=100/4.023=24.857MVA三相短路电流有效值Id(3)=Ij/Xjs=144.338/4.023=35.878kA三相短路冲击电流ic(3)=1.414KchId(3)=1.414*1.8*35.878kA=91.330kA三相短路电流全电流有效值Ic(3)=[1+2(Kch-1)2]0.5Id(3)=[1+2(1.8-1)2]0.5*35.878kA=54.175kA两相短路冲击电流ic(2)=0.866ic(3)=0.866*91.330kA=79.092kA两相短路电流有效值Id(2)=0.866Id(3)=0.866*35.878kA=31.070kA两相短路电流全电流有效值Ic(2)=0.866Ic(3)=0.866*54.175kA=46.916kA3.计算结果短路点1短路容量Sd=500.000MVA三相短路冲击电流ic(3)=69.986kA三相短路电流有效值Id(3)=27.493kA三相短路全电流有效值Ic(3)=41.514kA两相短路冲击电流ic(2)=60.608kA两相短路电流有效值Id(2)=23.809kA两相短路全电流有效值Ic(2)=35.951kA短路点2短路容量Sd=366.300MVA三相短路冲击电流ic(3)=51.271kA三相短路电流有效值Id(3)=20.141kA三相短路全电流有效值Ic(3)=30.412kA两相短路冲击电流ic(2)=44.401kA两相短路电流有效值Id(2)=17.442kA两相短路全电流有效值Ic(2)=26.337kA短路点3短路容量Sd=24.857MVA三相短路冲击电流ic(3)=91.330kA三相短路电流有效值Id(3)=35.878kA三相短路全电流有效值Ic(3)=54.175kA两相短路冲击电流ic(2)=79.092kA两相短路电流有效值Id(2)=31.070kA两相短路全电流有效值Ic(2)=46.916kA'