0S时:If G110,0?2.92?175/0.85?1.511KA;
3?230175/0.85?1.299KA;
3?230175/0.85?1.273KA;
3?2300.1S时:If G110,0.1?2.51?0.2S时:If G110,0.2?2.46?1S时:If G110,1?2.57?175/0.85?1.330KA;
3?230175/0.85?1.381KA;
3?230175/0.85?1.418KA;
3?2302S时:If G110,2?2.67?4S时:If G110,4?2.74?连接2200kV系统发电机送至d1点的短路电流: 0S时:If G220,0?6.13?3?175/0.85?9.515KA;
3?2303?175/0.85?6.721KA;
3?2303?175/0.85?6.364KA;
3?2300.1S时:If G220,0.1?4.33?0.2S时:If G220,0.2?4.10?1S时:If G110,1?3.61?3?175/0.85?5.604KA;
3?2303?175/0.85?5.123KA;
3?2303?175/0.85?4.688KA;
3?2302S时:If G220,2?3.30?4S时:If G220,0?3.02?2、短路点d2
0.0710.1100.655d2100.6500.2140.214 合并串并联支路
0.0710.1100.6551d20.4320.2140.864 (2)、转移电抗计算
①、110kV系统对短路点d2的转移电抗:
XS110f?0.110?1?0.655?1.765;
②、220kV系统对短路点d2的转移电抗:
XS220f?0.071?0.655?0.726;
③、连接在110kV母线上的发电机组对短路点d2的转移电抗:
XG110f?0.864?1?0.655?2.519;
④、连接在220kV母线上的2台发电机组对短路点d2的转移电抗:
XG220f?0.432?0.655?1.087;
⑤、短路点d2连接发电机组对短路点d2的转移电抗:
XGf?0.214;
(2)计算电抗:
220kV系统和110kV系统较发电机可以看做无穷大功率电源处理,直接计算其对的短路点d2电流;
①、连接在110kV母线上的发电机组对短路点d2的计算电抗:
XG110js?2.519?175/0.85?0.5186;
10002?175/0.85?0.4476;
1000②、连接在220kV母线上的3台发电机组对短路点d2的计算电抗:
XG220js?1.087?③、短路点d2连接发电机组对短路点d2的计算电抗:
XGjs?0.214?175/0.85?0.0441;
1000(5)短路电流标幺值
①、110kV系统对短路点d2的短路电流:
Is110??1?0.5666;
1.17651?1.3774; 0.726②、200kV系统对短路点d2的短路电流:
Is220??③、短路点d2连接发电机组对短路点d2的短路电流:
Is??1?4.673; 0.214④、连接在110kV母线上的发电机组对短路点d2的短路电流:
查《电力工程电气设计手册·电气一次》手册第137页Xjs?0.5186可知:
IG220,0?2.18;IG220,0.1?1.96;IG220,0.2?1.95;IG220,1?2.13;IG220,2?2.29;IG220,4?2.48;⑤、连接在220kV母线上的3台发电机组对短路点d2的短路电流:
查《电力工程电气设计手册·电气一次》手册第137页Xjs?0.4476可知:
IG220,0?2.50;IG220,0.1?2.08;IG220,0.2?2.05;IG220,;1?2.21IG220,2?2.35;IG220,4?2.50;
(6)短路电流有名值 电流基准值:IB?SB1000??36.701KA 3UB3?15.75短路点d2时110kV系统送至的短路点d2电流:
IfS110?0.5666?36.701?20.795;
短路点d2时220kV系统送至的短路点d2电流:
IfS220?1.3774?36.701?50.552;
短路点d2连接发电机组对短路点d2的短路电流:
IfS?4.673?36.701?171.504;
连接110kV系统发电机送至d2点的短路电流: 0S时:If G110,0?2.18?175/0.85?16.462KA;
3?15.76175/0.85?14.810KA;
3?15.75175/0.85?14.734KA;
3?15.750.1S时:If G110,0.1?1.96?0.2S时:If G110,0.2?1.95?