电力设计中短路电流的计算机算法

Short-Circuit Currents Calculation Method with Computer for Electric Power Design

在电力设计中,电气设备和载流导体的选择必须进行短路电流的计算.针对通常计算短路电流是以手工形式进行的问题,提出了短路电流的计算机算法.该算法根据电力网络特点及同步电机过渡过程理论,采用导纳矩阵法,推导出求解转移阻抗的数学模型,经换算进一步得到电源的运算阻抗,再用插值法查取存入计算机中的相应的运算曲线,以代替人工查'运算曲线数字表',从而自动实现短路电流的求解,算法简单可行.根据该算法编写的程序,可计算具有1 000个节点、2 000条支路、300台发电机和150个故障点的网络的三相短路电流计算.程序中插值法计算结果的小数点后3～4位有效数字与'运算曲线数字表'一致.对于具有20个节点的小型电力网络系统来说手工计算需要2 d,而通过计算机计算只需10 min.

In electric power design, selection of electrical equipment and live conductor must base on the calculation of short-circuit currents. Commonly, electrical engineers calculate short-circuit currents by handwork. This paper will be according to characteristic of electric tion generator, adopt admittance matrix method to power network and transition process principle of synchronizaeduce mathematics model for transfer impedance＇s solution, electrical engineers obtain power supply＇s calculating impedance through conversion, and find relevant calculating curve kept in computer by insert value method, take the place of handwork to find “figure table of calculating curve”, thereby automatically gained result of short-circuit currents, so the arithmetic is simply and feasible. By the program designed with above arithmetic, electrical engineers can calculate three-phase short-circuit currents with 1 000 nodes, 2000 branches, 300 generators and 150 fault locations. In the program, calculation resuh＇s effective number will be in accordance with the “figure table of calculating curve”. For a small electric power system network with 20 nodes, electrical engineers will need two days by handwork calculation, therewith only in ten minutes by computer.