说明：  本程序是用节点导纳矩阵计算三相短路电流 输入数据--形成节点阻抗矩阵--选择故障点---计算短路电流----计算个节点电压---计算指定支路的电流
(this procedure is used node admittance matrix calculation of three-phase short-circuit current input data-- forming node impedance matrix-- election Optional fault--- calculation of short-circuit current-voltage computing nodes designated calculated slip road--- Electricity)