This paper presents an approach to the calculation of unbalanced fault currents in shipboard power systems based on the application of Millman’s theorem. A full analysis of the time-variant fault current produced by a synchronous generator in a typical marine power system is provided; three phase three wire for principal loads and four wire earthed neutral for hotel loads. Hand calculation results obtained using a Millman’s theorem based approach are contrasted with results obtained by computer simulation and baselined against hand calculation results produced using conventional symmetric component methods. Results show that the Millman’s theorem based approach calculates fault levels that are broadly comparable to those produced using symmetric component methods. The Millman’s theorem based approach is however conceptually much simpler to apply than the conventional symmetric component method as it does not use the fictitious sequence components and networks employed by the symmetric component technique.

本文提出了一种基于米尔曼定理的舰载电力系统不平衡故障电流计算方法。对典型船用电力系统中同步发电机产生的时变故障电流进行了全面分析；主要负载的三相三线和酒店负载的四线接地中性线。使用基于米尔曼定理的方法获得的手工计算结果与通过计算机模拟获得的结果进行对比，并以使用传统对称组件方法产生的手工计算结果为基准。结果表明，基于米尔曼定理的方法计算的故障级别与使用对称分量方法产生的故障级别大致相当。