Analysis of unbalanced fault operating conditions of ship electric networks via Millman’s theorem

ABSTRACT The aim of this paper is in continuation with previous works of other authors, to demonstrate a methodology of analysing unbalanced operating conditions of ship electric energy systems via Millman’s theorem. Its advantages consist in being simple in implementation (either in time domain or in phasor mode) especially by non-electric power engineers, in contrast to the more complicated method via the symmetric components (or sequence networks). Furthermore, the method can be well applied to most ship electric systems, the configurations of which are not as complicated as in inland grids, e.g. with meshed loop double-circuit transmission networks, etc. The analysis covers most unbalanced case studies, i.e. single- and two-phase short-circuit faults as well as single- and two open-circuit faults.