Abstract: The calculation method of direct-current (DC) short-circuit current and analysis of selective protection of fuses are important aspects of the design of the DC integrated power system. The design directly affects the selective protection scheme of fuses in the DC distribution system and the operational stability of the DC distribution system. The calculation principle and method of the single module short-circuit current in marine DC distribution system are presented for equivalent calculation of the ship’s DC distribution system. By selecting different short-circuit points, the impact of different short-circuit points on the DC comprehensive power system during short circuit. The short-circuit currents of different branches are calculated to determine the fuse specification through the actual I2T curve of the branch. The error between the simulation results obtained from the equivalent model simulation and the practical calculation is within 1% by analyzing the practical examples. By using the MATLAB/SIMULINK equivalent model simulation method, the calculation of the short-circuit current of the DC distribution system and the reasonable selection of the fuse can be conducted without establishing a detailed SIMULINK model and performing tedious formula calculations.

Key words: short-circuit current, selective protection, MATLAB/SIMULINK, calculation method

摘要： 船舶电力系统短路计算及断路器的选择性保护分析是直流综合电力系统设计的重要一环,直接影响直流配电系统的运行稳定性以及熔断器选择性保护方案。该文阐述了船用直流配电不同模块的建模以及系统的短路电流计算过程,对船舶直流配电系统进行等效计算,通过选取不同的短路点,探究不同短路点短路时对直流综合电力系统的影响;对不同支路的短路电流进行计算,通过支路实际 I²t 曲线确定熔丝规格,结合实际算例进行分析,等效模型仿真得到的仿真结果与实际计算的误差在 1% 之内。通过 MATLAB/SIMULINK 软件,等效模型仿真的方式,不需要建立详细的SIMULNK 模型,也无需进行繁琐的公式计算,即可对直流配电系统进行短路电流计算并对熔断器进行合理选型。

关键词: 短路电流, 选择性保护, MATLAB/SIMULINK, 计算方法