则短路电流
11 ?X2X//X?1(X?X)13T1T2211= ?10.18250.0039??0.045?0.001?2Id?=5.479+38.610 =44.089
换算到110kV短路电流有名值，
\*Id2?Id2Sb100?22.135 kA ?44.089?3?1153Ub根据《电力工程电气设计手册》的相关规定，取电流冲击系数 Kch?1.8 当不计周期分量的衰减时，短路电流全电流最大有效值
Ich?1.51I''?33.4238 kA
当不计周期分量衰减时,
冲击电流 ich?2KchI''?2?1.8I''?2.55I''?56.4443 kA 短路容量 S?3UbI''? 3．k(3)点短路计算 K3短路点为双城电厂330kv母线短路，此短路的的短路电流由110kv母线和变电站330kv母线同时提供，则其短路阻抗为：
X1 X3 K3 3?115?22.135=4408.84 MVA
XT1 330kV XT2 110kV X2 电厂330kv母线短路 短路电流标幺值：
Id?11??X1//?X2??XT1?XT2???X32?? =1 0.0083//0.2045?0.00741 0.0079?0.0074==65.359 换算到双城电厂330kV侧有名值 \*Id3?Id3
100Sb? 10.6599KA ?65.359?3?3453Ub短路电流全电流最大有效值及冲击值 Ich?1.51I''?16.0964 KA ich?2.55I''?27.1827 KA 短路容量：S?3UI?3?345?10.6599=6369.71 MVA 3．k(4)点短路计算
35kv母线侧短路，汉源330kv母线、电厂330kv母线和110kv母线提供短路电流。
35kV K（4） ''X1 X3 X *1330kV 110kV * X3*X 2 35kv母线短路
X2 X1*?X1//3?
1XT1=0.0039+0.0225=0.0264 2
*X2?X2?*X3?1XT2=0.1825-0.001=0.11805 21XT3=0.0275 2*1*3*0.0264?0.0275X1*?X3=0.0264+0.0275+=0.06004 X?X?X?*0.11805X2*13**0.11805?0.0275X2?X30.11805?0.0275?==0.1231 X?X?X?*0.0264X1*23*2*3短路电流标幺值：
*Id?1111?=16.6555+8.1234=24.7789 ??**X13X230.060040.1231换算到35kV侧短路电流有名制：
I\?I*取冲击系数：Ksh?1.8
SJ100?24.7789??38.662kA 3Uav3?37短路电流全电流最大有效值：
Ish?1.52?38.662?59.230kA
冲击电流：
ish?1.82I\?1.8?2?38.662?98.4025kA
短路容量：
S?3UI\?3?37.5?38.662?2511.0969MVA
330kV、110kV、35kV各侧计算值
短路点 基准电压 短路电流标短路电流有名值I’’ (kA) 短路冲击电流ish (kA) 短路电流最大有效值Ish 短路容量 S (MVA) UB
幺值Id *(kA) K1 K2 K3 K4
330 110 330 35 260.507 44.089 65.359 24.7789 43.597 22.135 10.6599 38.662 111.172 56.4443 27.1827 98.4025 65.831 33.4238 16.0964 59.230 26050.951 4408.84 6369.71 2511.0969