求供电线路K点发生三相短路的短路电流、冲击电流iim、短路容量Sk。系统为无穷大功率电源,线路阻抗为X0=0.4Ω／Km

解:(1)画出等效电路图: （2）阻抗计算: 系统阻抗: 因系统为无穷大功率电源，所以Xs = 0 Ω 导线阻抗: Xw = Xo * L = 0.4*10 = 4 Ω (3) 系统总阻抗: X∑= Xs + Xw = 0+4=4Ω (4) K点短路电流: Is = Vav/（*X∑） = 6.3/（* 4） = 0.909 kA 冲击电流: iim = 1.8 Is = 1.84*0.909 = 1.637 kA 短路容量: Sk= Vav * Is = *6.3*0.909 = 9.919 MVA