邵阳学院毕业设计(论文)
①在最大运行方式下
110kV母线上发生三相短路,即f1点短路:
如图8.3可知电源点对短路点的转移阻抗为
Xf1?X13?0.101
起始次暂态电流为: I\?短路处电压级的基准电流为
IB?SB3VBE30.101??1 Xf10.101?100?0.502 3?115短路电流有名值: I(3)?1?0.50?20.5 02kA10kV母线上发生三相短路,即f2点短路:
如图8.3可知电源点对短路点的转移阻抗为:
Xf2?X13?X14?0.101?0.21?0.311
起始次暂态电流为:
I\?E30.101??0.325 Xf20.311短路处电压级的基准电流为:
IB?SB3?VB?100?5.499 3?10.51. 787kA?99短路电流为: I(f23)?0.32?55.4110kV线路侧发生三相短路,即f3点短路:
等值电路图可简化为如下图8.4:
X2X7X8X1 X6X5 X1 X16f3f3
图8.4 等值网络图的简化
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邵阳学院毕业设计(论文)
X16?X9?X10?X2?0.134?0.038?0.2?0.372
X17?X1?X160.372?0.04??0.039
X1?X160.372?0.04I???1?25.641 0.039I(3)?25.641?0.502?12.871kA
②最小运行方式下:
f1点发生三相短路
等值电路图可以简化为如下图:
f1E2X2X8X5X1E1
图8.5 等值电路化简图
X8?X2?0.076?0.2?0.237 X1?X5?0.08?0.302?0.382 0.237?0.3820.091X18???0.417
0.237?0.3820.6190.101I????0.242
0.417I(3)f1?0.242?0.502?0.122kA
f2点发生三相短路
等值电路图如图8.6所示
f2E2X2X8E1X4X3X5X1
图8.6 等值电路图化简图
X1?X5?X3?0.04?0.302?0.42?0.762 X2?X7?X4?0.2?0.076?0.42?0.696
X19?0.762?0.696?0.330
0.762?0.6960.101I(3)??0.306
0.330- 37 -
邵阳学院毕业设计(论文)
f3点发生三相短路
f3E2X2X7X5X1E1
图8.7 等值电路图化简图
X2?X7?X5?0.578
X20?0.578?0.040.0231??0.0397
0.578?0.040.5821I(3)??25.19kA
0.0397I(3)?0.502?25.19?12.44kA
(2)其他简单不对称短路 ①最大运行方式下
f1发生短路,正负序图如图8.3,零序图如图8.8
f1X10图8.8 零序图
X9
X1??X2??X13?0.101
X0??X9?X100.134?0.038??0.029
X9?X100.134?0.038单相短路: I(1)?0.1010.101 7??0.430.10?1?20.0290.2310.4?370. 219kA(1)?0.50?2正序电流有名值: I1单相短路电流: I(1)?3?0.219?0.657kA 两相短路: I(2)?0.101?0. 50.10?120?.50.2 51kA(2)?0.50?2正序电流有名值: I1两相短路电流: I(2)?3?0.25?10.4 35kA- 38 -
邵阳学院毕业设计(论文)
(1.1)两相接地短路 I*1?0.1010.101??0.815
0.101?0.0290.1240.101?0.101?0.029(1.1)I1?0.502?0.851?0.427kA
I(1.1)?31?X2(X2??X0?X0?)2(1.1)?I1?31???0.101?0.029?0.427?0.672kA 2(0.101?0.029)f2点发生短路
正、负序图如图8.3,零序图如图8.9
f2X14X15
图8.9 零序图
X1??X2??X15?X14?0.101?0.21?0.311
X0??0.029?0.21?0.239
(1)单相短路: I*1?0.1010.101??0.119
0.311?2?0.2390.852(1)I1?0.119?5.499?0.651kA
I(1)?3?0.651?1.953kA
0.101(2)两相短路: I*1??0.162
0.311?2(2)I1?5.499?0.162?0.893kA
(1.1)两相接地短路:I*1I(2)?3?0.893?1.547kA
0.1010.101???0.227
0.311?0.2390.4460.311?0.311?0.239(1.1)I1?5.499?0.227?1.248kA
I(1.1)?31?0.311?0.239?1.248?1.63kA 2(0.311?0.239)f3点发生短路
正、负序图如图8.4,零序图如图8.10
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邵阳学院毕业设计(论文)
f3X9X10
图8.10 零序图
X1??X2??(X2?X9?X10)//X1?(0.2?0.038?0.134)//0.04?0.039
X0??0.134?0.038?0.172
(1)单相短路: I*1?11??4
0.039?2?0.1720.25(1)I1?4?0.502?2.008kA
I(1)?3?2.008?6.024kA
(2)两相短路: I*1?1?12.82
0.039?2
(2)I1?0.502?12.82?6.436kA
I(2)?3?6.436?11.147kA
(1.1)发生两相接地短路:I*1?11??14.085
0.039?0.1720.0710.039?0.039?0.172(1.1)I1?0.502?14.085?7.07kA
I(1.1)?31?0.039?0.173?7.07?12.245kA
(0.039?0.173)2在最小运行情况下
f1发生短路
正、负序图如图8.5,零序图如图8.11
f1X8X5
图8.11 零序图
X1??X2??X13?0.417
X0??X5?X70.302?0.076??0.278
X5?X70.302?0.076- 40 -