电力系统分析(答案在题后) 下载本文

jX2 jX3

jX4 jX5 ? Uka0

3.答:

G1 T1 T2 T3 G3 K(1) L1 L2 L3 5 6 7 9 11 12 13 14

1 2 3 8 XQ1 4 XQ2 15 10 G2

G1 T1 T2 G3 L1 L2 L3 T3 XQ1 大地

? U0G2 XQ2

G1 T1 T2 G3 L1 L2 L3 T3 XQ1 大地 ? U0G2 XQ2

4.答:

?(1.1) Uka?I(1.1)kc

?I(1.1)kc1

?I(1.1)ka2?I(1.1)kc2

?I(1.1)ka1

?I(1.1)kb2

?(1.1) U?(1.1)Uka1ka2(1.1) ?Uka0?I(1.1)ka0

?(1.1) U?(1.1) U?(1.1) U?(1.1) Ukc1kb2kc2kb1?I(1.1)kb1

?I(1.1)kb

5.

??(1)I(1)kc1 Ikb2

?(1) Uka1?I(1)ka0 ??(1)I(1)ka1 Ika2

?I(1)ka?(1) Ukc2?(1) Ukb2?(1) Ukc1??(1)I(1)kc2 Ikb1

?(1) Ukcf L1-1 L1-2 T-1 ?(1) Uka2?(1) Uka0?(1) Ukb1?(1) Ukb

L2 T-2 6. 答:

XL1-10 XL1-20 Uf0 XL20 xT-2

7.

解:

8.

答:

四、分析题 1、

解:设SB=100MV·A,UB = Uav

XG?XdXB1100?SB?0.125??0.106100SN0.85S100?UK%B?0.105??0.263SN40SB100?0.4?20??0.0622115Uav100?0.502(kA)3?115XL20?xlX1??X2??0.106?0.263?0.06?0.429 IB?SB?3UB

??1?Ia??I有名X1??I???IB?0.502?1.16?0.58(kA)11??1.16?X2?0.429?0.429??1?3?0.58?1.01I?3Ia(kA)

2、 解:

'U1tmin?U2minU2N11?107.5??112.6(kV)105U2'Cmin选用110+2.5%即112.75kV分接头,确定k=112.7511U2CmaxU'2max2QC?(U2Cmax?)k

Xk10.511112.752?(10.5?97.1?)()?8.74(Mvar)129.6112.7511

3.解:

正序网负序网 零序网

正序等值网络Xkk1?0.146 负序等值网络Xkk2?0.16

零序等值网络

Xkk0?(0.056?0.09)?(0.09?0.087)?0.08

(0.056?0.09)?(0.09?0.087)1100??0.65KA

0.146?0.16?0.083?2300.09?0.087?0.36KA

(0.056?0.09)?(0.09?0.087??I??I??各序电流值为Ia1a2a0??0.65?流过开关M的零序电流Im0??0.65?0.36?0.29KA 流过开关P的零序电流Ip0???Ima???流过开关M的各相次暂态短路电流?Imb??

?I???mc??11?1a2???1a1??0.36??1.66??0.65????0.29?KA a??????2a????0.65?????0.29????I??I??0.29KA 流过开关P的各相次暂态短路电流Ipapbpc??3I??1.08KA 流过左边变压器中线的次暂态电流Imnm0??3I??0.87KA 流过右边变压器中线的次暂态电流Ipnp0

4、解:

(1) 发电机:为发电机专用电压等级,故VGN?13.8kV 变压器T-1:额定电压为121/38.5/13.8 kV 变压器T-2:额定电压为35/11 kV 变压器T-3:额定电压为10/0.4 kV

电动机:其额定电压为网络额定电压,VMN?0.38kV (2)各变压器实际变比为:

变压器T-1:kT1(1?2)?(1?0.025)?121/[(1?0.05)?38.5]?3.068 kT1(1?3)?(1?0.025)?121/13.8?8.978 kT1(2?3)?(1?0.05)?38.5/13.8?2.929 变压器T-2:kT2?35/11?3.182

变压器T-3:kT3?(1?0.025)?10/0.4?24.375

5.解: