1电气主接线及所用高压接线设计1 - 图文(5)

2.2．三相短路

1． 35KV系统三相短路电流计算

220KV35KVX8X2X73D1X1

<图三>

21X2X8<图四>

X9?X7?X1?0.0084?0.028?0.0364 <图五>

XXD1

X?1?X9?X8?X9?X80.0364?0.017?0.0364?0.017??0.16 X20.5X?2?X2?X8?X2?X80.5?0.017?0.5?0.017??14.72 X90.0364计算电抗

Xijs1?XSN118000?0.16??28.8

?1SB100SN2100?14.72??14.72

?2SB100Xijs2?X查曲线求得 1I1??0.0347

28.81I2??0.07

14.72?3?IDI?0.0347?180003?37?0.07?1003?37?9.85KA

2． 220KV系统三相短路电流计算 <图六>

XXD1 <图七>

X?1?X7?X1?0.0084?0.028?0.0364

X?2?X2?0.5

计算电抗

Xijs1?XSN118000?0.0346??6.552

?1SB100

Xijs2?XSN2100?0.5??0.5

?2SB100查曲线求得

I1?0.1526

I2?2

?3?ID2?0.1526?180003?230?2?1003?230?7.4KA

3． 500KV系统三相短路电流计算 <图八>

220KV35KVX8X2X73D3X1

<图九>

21D3

XX?1?2?X1?0.028

?X7?X2?0.0084?0.5?0.5084

计算电抗

Xijs1?XSN118000?0.028??5.04

?1SB100

Xijs2?XSN2100?0.5084??0.5084

?2SB100查曲线求得 1I1??0.198

5.04I2?1.9

?3?ID3?0.198?180003?525?1.9?1003?525?4.139KA

2.3单相短路计算

2.3.1 35KV系统单相短路电流计算 I\?0

由于主变压器为自耦变压器其35KV侧为三角形接线,而零序电压施加在各种类型变压器绕组的三角形(d形)侧或不接地星形(Y形)侧时,无论其他侧绕组接线方式如何,变压器中都没有零序电流流通,此时变压器的零序电抗X0??所以35KV系统单相短路电流为零

2.3.2 220KV系统单相短路电流计算 正序网 <图十>

X1X7X▲X2 负序网 <图十一>

X2X1X7 零序网 <图十二>

X2X1X7X8X.5??0.028?0.0084??2?X2//?X1?X7??00.5?0.028?0.0084?0.03X?0?X2//?X1?X7?//X8?0.005

X??X?2?X?0?0.03?0.005?0.035

XX?G1f??X1?X7????111???X??1?X7X2X????0.0364?0.035???111?

?0.0364?0.035?0.5???0.073X???111?G2f?X2X???X1?X?7X?2X????0.5?0.035???111?

?0.0364?0.035?0.5???1.016计算电抗

Xijs1?XSN1G1fS?0.073?18000?13.14 B100XSN2ijs2?XG2fS?1.016?100100?1.016 B查曲线求得 I?1113.14?0.076

I2?0.98

I?1?D4?0.076?180001003?230?0.98?3?230?3.64KA

I\?3I?1?D4?3?3.63?10.92KA