短路电流计算
系统接线示意图
1-6
? 高压厂变及高压备用变的正序,负序电抗(高压绕组)不可能是0.001。
高压备用高压绕组零序电抗也不可能是2.5,计算有误(见设计手册第142
页、165页、166页的计算公式)
? 高压厂及高压备用变均为分裂变,额定容量S=40MVA,高压厂变半穿
‘‘越电抗X=14%,高压备用变半穿越电抗为X=18.5%。 1-21-2
? 高压厂变正负序电抗
143.5',,X/1,Kf/4 X=== /1,0.07471-212,1004
SKf,,j高压绕组正序电抗为 1,X,,,1,24S,,eB
3.51000,, = 1,,0.0747,,,440,,
= 0.233
负序电抗=正序电抗
S1j低压绕组正序电抗为 Kf,X,1,22SeB
11000 = ,3.5,0.0747,240
= 3.268
负序电抗=正序电抗
? 高压备用变的正序,负序及零序电抗
18.53.5,,',,X/1,Kf/4/1, X=== 0.0987,,12,1004,,
高压绕组正序电抗
3.51000,, X== 0.3081,,0.0987,?,,440,,
X=X= X= 0.3080.308??0
2-6
低压绕组正序电抗
3.51000 X== ,0.0987,4.318?240
X=X1= X= 4.3184.31820
? 正负序及零序电抗图和综合电抗(220KV系统)
? 正负序电抗图及综合计算
1X== 0.149?1111,,1.2471.2470.195
1X== 0.147?2111,,1.2071.2070.195
? 零序电抗图及综合计算
由于6KV侧中性点串接有100欧电阻,根据设计手册第142页的计算
公式
3-6
XZX,,3,;,,,,4.318,3,100,2.313,X=X,/2== 0.308,/21.4560B1XZX,,3,;4.318,3,100,2.313,
'S18.51000Xj12,=== X,;,0.5,X2.313,,,;,S10040100eB
1X== 0.106;,1111,,,0.520.521.4560.205
? 不对称短路电流计算
1000I? 单相短路电流 (== kA) 2.51J2303正序电流标么值
11''(1)I === 2.488*1X,X,X0.149,0.147,0.1061,2,;,正序电流有名值
''(1)''(1)I === kA 2.51,2.4886.245I,I1*1j
单相短路电流
''(1)''(1)3I === kA I3,6.24518.7351
? 两相短路电流
正序电流有名值
I2.51j''(2)I === kA 8.481X,X0.149,0.1471,2,
两相短路电流
''(2)''(2)3,8.483,I === kA I14.6881
? 两相接地短路电流
4-6
正序电流有名值
2.51Ij''(1,1)I=== 11.91910.147,0.106XX2,0,0.149,X,1,X,X0.147,0.1062,0,两相接地短路电流
XX''(1,1)''(1,1)20,, = 31,,II1X,X20,,
XX2,0, = 3,1,,11.919,XX2,0,
= kA 17.957