电力系统分析典型计算题2————————————————————————————————作者：————————————————————————————————日期：[例2-1]一条220kV的输电线,长180km,导线为LGJ-400(直径2.8cm),水平排列,相间距7m,求该线路的R,X,B,并画等值电路.解:电阻:kmSr/08.04005.3114.1418008.01lrR电抗:cmDeq88270027007003kmrDxeq/42.04.18.0882lg1445.08.0lg1445.016.7518042.01lxX电纳:kmSrDbeq/107.2104.1882lg58.710lg58.76661SlbB66110486180107.2等值电路:[例2-2]220kV架空线,水平排列,相间距7m，每相为2402LGJQ分裂导线，计算直径21.88mm，分裂间距400mm，求每相单位长度的电阻、电抗和电纳。解:电阻:kmSr/660.040225.311＝电抗:757.62400288.219.0dDDssbmmDeq882070002700070003kmDDxsbeq/31.0757.628820lg1445.0lg1445.01电纳:151.66400288.21rdreqkmSrDbeqeq/10567.310151.668820lg58.710lg58.76661[例2-3]一长度为600km的500kV架空线路，使用4×LGJQ-400四分裂导线，611110.0187,0.275,4.0510,0rkmxkmbSkmg。试计算该线路的形等值电路参数。解（1）精确计算。66(0.01870.275)0.2756(86.11)4.0510906000.27564.0510(83.1190)20.633988.060.021460.6335()0.5()0.01730.59220.592488.330.5924llZzrjxjkmkmyjbSkmlzyljshleejshlKl88.330.93450.270.633988.06()0.5()0.80610.01272(1)0.3886176.321.0351.07()0.3755176.39llYchleejchlKlshl计算形等效电路参数：6330.93450.270.275686.11600154.53860382(2)1.0350.074.0510903001.2581089.931.25810ZYZKzlYKjblSSjS（2）使用近似算法计算。2262226311110.2754.05600100.8663311()0.9336111.03312(9.72153.9)24.05103001.0331.25510rxbrxkxblrkbxlxkxblZkrljkljYjSjS与准确计算相比，电阻误差-0.4%，电抗误差-0.12%，电纳误差-0.24%，本例线路长度小于1000km，用实用近似公式计算已能够满足精确要求。如果直接取1,)(11.22165)ZYKKlj11则Z=（r+jx这时，电阻误差达15%，电抗误差7%，电纳误差-3.4%，误差已较大。例2－4330kV架空线路的参数为,/0579.00kmr,/316.00kmx,00g./105.360kmsb试分别计算长度为100，200，300，400和500线路的π型等值参数的近视值，修正值和精确值。解首先计算100km线路的参数（一）)6.3179.5(100)316.00579.0()(00`jjljxrZsjsjljbgY4600`1055.3100)1055.30()((二)修正参数计算9963.01001055.3316.031131126200lbxkr9982.0100]316.0/1055.30579.01055.3316.0[611)06112626200200(lxbrbxkx0009.11001055.3316.01211121126200lbxkb)5431.317686.5(100)316.09982.00579.09963.0()(00`jjljxkrkZxrssjljbkYb460`105533.31001055.30009.1（三）精确参数计算060000192.58255.300)2201.275914.299()1055.3/()316.00579.0()/()(jjjjjbgxrZckmbgxrjjjjj146000010)6355.09663.0()1055.3)(316.00579.0())((2410)6355.09663.0(10010)63555.109663.0(jjl计算双曲线函数。利用公式sh(x+jy)=shxcosy+jchxsinych(x+jy)=chxcosy+jshxsiny将l之值代入，便得222222210)6160.109609.0()106355.10sin()109633.0()106355.10cos()109633.0()106355.10109633.0(jjchshjshlsh2222222101026.09944.0)106355.10sin()109633.0()106355.10cos()109633.0()106355.10109633.0(jjshshjchlchII型电路的精确参数为sjsjjlshlchYjjjlshZZZcc422`10)5533.30006.0(5429.317684.5)1101026.09944.0(2)1(2`)5429.317684.5(10)6160.109609.0()2201.275914.299([例2-5]有一台SFL120000/110型的向10kV网络供电的降压变压器，铭牌给出的实验数据为：试计算归算到高压侧的变压参数。解由型号知，.110,20000kVVAkVSNN高压侧额定电压各参数如下：08.4102000011013510322322NNSTSVPR53.6310200001001105.1010100%32322NNSTSVVXssVPGNT6333201082.11011022101011110102.1310110100200008.010100%21632320NNTNNTVVssVSIBk8.0%,22,5.10%,13500IkWPVkWPss例2-6三相三绕组降压变压器的型号为SFPSL-120000/220，额定容量为120MVA/120MVA/60MVA，额定电压为：220kV/121kV/11kV,kWPS601)21(，kWPS5.182)31(，kWPS5.132)32(，85.14%)...
