1--10I’2=I’2*×(SN/1.732Uav)=6.237×(93.75/1.732×37)=9.12(kA)I”2=I”2*×(SN/1.732Uav)=3.081×(93.75/1.732×37)=4.51(kA)取冲击系数Kim=1.85,则:冲击电流ich=1.414KimI’2=1.414×1.85×9.12=23.86(kA)短路容量:Sk’2=·I·Uk2=×9.12×37.5=592.34(MVA)Sk”2=·I·Uk2=×4.51×37.5=292.92(MVA)当K3点短路时简化等值网络图如下:X20X5K3X22X23K3X22X21X20=X1+X2+X3+X4=0.691X21=X6+X7//X8//X9//X10//X11=0.136X22=0.126X23=X20//X21+X5=0.288Xf=X23//X22=0.088查运算曲线得:t=0s时,I’3*=8.963t=4s时,I”3*=2.512I’3=I’3*×(SN/1.732Uav)=8.963×(93.75/1.732×10.5)=46.2(kA)I”3=I”3*×(SN/1.732Uav)=2.512×(93.75/1.732×10.5)=12.95(kA)取冲击系数Kim=1.85,则:冲击电流ich=1.414KimI’3=1.414×1.85×46.2=101.4(kA)短路容量:Sk’3=·I·Uk3=×46.2×10.5=840.19(MVA)Sk”3=·I·Uk3=×12.95×10.5=235.51(MVA)1.4短路电流计算结果表短路点编号基准电压短路电流(kA)冲击电流(kA)短路容量(MVA)t=0t=4sK11152.491.516.51495.96K237.59.125.5123.86592.34K310.546.212.95101.4840.19
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