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Power quality (PQ) is becoming more and more critical issue in shipboard microgrid systems (SMGs). Especially, the impact of voltage unbalance combined with harmonic distortions on the SMG behavior has not been fully investigated. In this paper, simple PQ assessment models and a series of controlled experiments are proposed and carried out in a real ship under sea-going conditions. The ship experimental results are presented and discussed considering nonlinear bow thruster load and high power ballast pump loads under unbalanced and harmonic voltage conditions. In addition, the analysis of bow thruster current harmonic surges during the ballast pump start-up is presented. Furthermore, the voltage/current distortions of a working generator, bow thruster and pump loads are analyzed. The paper provides a valuable analysis for coping with PQ issues in the SMG. [ABSTRACT FROM AUTHOR]

The paper is focused on the problem of load sharing between generators running in parallel in ship microgrids loaded by variable-speed drives with power converters. It is based on an experimental study of a number of real cases recorded on three ships. Chosen power quantities defined in the IEEE 1459-2010 standard are calculated, and their sharing between generators working in parallel in ship systems are assessed. Particularly, sharing of active, nonactive, and apparent power as well as active, reactive, and apparent power of voltage and current fundamental components is determined for various loads. The levels of voltage and current distortions as well as harmonic power flow are also assessed. The results are commented on in the wake of related provisions of ship classification societies rules. Finally, it has been determined that there are differences between sharing of various power components, which must not be neglected, particularly in the case of nonactive power and fundamental reactive power. Therefore, amendments to related ship classification societies rules are necessary. [ABSTRACT FROM PUBLISHER]