高低压短路电流计算书_secret.doc

高低压短路电流计算书一 设计依据 电力工程电气设计手册电气一次部分 水利电力部西北电力设计院编 中国电力出版社工业与民用建筑配电设计手册 第二版 中国航空工业设计院编 水利电力出版社(p141页例题)二 设计过程d1短路点最大短路状态 2.1 元件短路阻抗计算过程 电力系统:X2 = Sj / Ss = 100 / 150 = 0.6667 双匝变压器:X3 = Uk%Sj / 100Sr = 5.5 100 / (100 4.0000) = 1.3750 双匝变压器:X4 = Uk%Sj / 100Sr = 5.5 100 / (100 4.0000) = 1.3750 电缆线路:X5 = X0 L = 0.304 1.000000 = 0.3040 架空线路:X6 = X0 L = 0.325 0.850000 = 0.2763 架空线路:X7 = X0 L = 0.325 0.850000 = 0.2763 异步电机:X8 = XdSj 1000 / Src = 0.156 100 1000 / 556 = 28.0576 异步电机:X9 = XdSj 1000 / Src = 0.204 100 1000 / 253 = 80.6324 异步电机:X10 = XdSj 1000 / Src = 0.156 100 1000 / 556 = 28.0576 发电机:X11 = XdSjCos / Pn = 0.1221 100 0.80 / 12 = 0.8140 2.2 系统网络变换计算过程 2.2.1 串联 X101 = X4 + X6 = 1.3750 + 0.2763 = 1.65132.2.2 串联 X102 = X3 + X7 = 1.3750 + 0.2763 = 1.6513 2.2.3 并联 X103 = 1 / (1 / X8 + 1 / X9 + 1 / X10) = 1 / (1 / 28.0576 + 1 / 80.6324 + 1 / 28.0576) = 11.9497 2.2.4 三角-星型变换: X104 = X101 X5 / (X101 + X5 + X102) = 1.6513 0.3040 / (1.6513 + 0.3040 + 1.6513) = 0.1392 X105 = X101 X102 / (X101 + X5 + X102) =1.6513 1.6513 / (1.6513 + 0.3040 + 1.6513) = 0.1392 X106 = X5 X102 / (X101 + X5 + X102) = 0.3040 1.6513 / (1.6513 + 0.3040 + 1.6513) = 0.7561 2.2.5 串联 X107 = X2 + X104 = 0.6667 + 0.1392 = 0.8059 2.2.6 串联 X108 = X11 + X105 = 0.8140 + 0.1392 = 0.9532 2.2.7 求分布系数: X109 = X总 / C1 = 1.1928 / 0.5419 = 2.2013 X110 = X总 / C2 = 1.1928 / 0.4581 = 2.6036 X总 = X107X108 / (X107X108 + X108X107) + X106 = 0.8059 0.9532 / (0.8059 0.9532 + 0.9532 0.8059) + 0.7561 = 1.1928 C1 = X108 / (X107X108 + X108X107) = 0.9532 / (0.8059 0.9532 + 0.9532 0.8059) = 0.5419 C2 = X107 / (X107X108 + X108X107) = 0.8059 / (0.8059 0.9532 + 0.9532 0.8059) = 0.4581 2.3 短路电流计算过程 G|S 系统发电机并联变换 G*X109,X110*X111 S|M 考虑异步电动机冲击变换 M*X111,X103*X112 X109=2.2013 I*=0.4543 I=4.1631 X110=2.6036 I*=2.7335 I=3.7576 X103=11.9497 I*=0.0846 I=0.7749 总阻抗 X111 = 1 / (1 / X109 + 1 / X110 + 1 / X103) = 1 / (1 / 2.2013 + 1 / 2.6036 + 1 / 11.9497) = 1.0845 I*总 = I*109 + I*110 + I*103 = 0.4543 + 2.7335 + 0.0846 = 3.2724(KA) 总短路电流有名值 I总 = I109 + I110 + I103 = 4.1631 + 3.7576 + 0.7749 = 8.6957(KA) 短路容量 S总 = 3 Uj I总 = 3 6.3000 8.6957 = 94.8867(MVA) 冲击电流 ich = ich系统 + ich发电机 + ich异步电机 = 2 Kch (I110 + I109) + ich异步电机 = 2 1.8000 (3.7576 + 4.1631) + 1.8628 = 22.0258(KA) 其中：ich异步电机 = 0.9 1.414 Kchm Kqm Irm / 1000 = 0.9 1.414 1.7000 6.1503 140.0000 / 1000 = 1.8628(KA) 全电流最大有效值 Ich = (Is + Im)2 + 2 (Kch - 1) Is + (Kchm - 1) Im2 = (7.9208 + 0.7749)2 + 2 (1.8000 - 1) 7.9208 + (1.7000 - 1) 0.77492 = 13.0483(KA) 两相短路电流Ik2 = 0.866I总 = 0.866 8.6957 = 7.5305(KA) 两相冲击电流ichk2 = 0.866ich = 0.866 ich = 22.0258(KA) 两相全电流有效值Ichk2 = 0.866Ich = 0.866 13.0483 = 11.2998(KA)三 设计结果1 元件结果表元件名称元件编号元件电阻元件电抗元件相保电阻元件相保电抗元件型号和基本计算参数电力系统X20.6667双匝变压器X31.3750双匝变压器X41.3750电缆线路X50.3040架空线路X60.2763架空线路X70.2763异步电机X828.0576异步电机X98