Assessment of Supply-Voltage Quality in a Ship’s Electric-Power System by Means of Computer Simulation

Abstract

A ship’s electric-power system (SEPS) provides reliable functioning of ship systems, as well as safety in navigation and the living conditions and work of the crew. SEPSs in large-displacement vessels can have a capacity of more than 100 MW and consist of thousands of interconnected components and subsystems. On ships with a propulsion system (PS), the SEPS powers both the PS, which consumes most of the power generated by a ship power plant, and numerous general consumers of power on the ship. The PS includes frequency converters with dc links; for a ship’s power plant, these converters are a high-power nonlinear load that causes significant voltage distortions in the ship’s network. When designing a vessel, at the stage of selecting the structure and components of the SEPS, electromagnetic compatibility between the PS and general vessel users needs to be provided. According to the requirements specified in the Russian Maritime Register of Shipping, the nonsinusoidal voltage in the ship’s electrical network must not exceed 10%. Computer simulation is the only effective tool for assessing the quality of ship-network voltage at the initial stages of design. In this paper, we present the results of estimating two alternative SEPS designs by means of the MATLAB Simulink package. It is shown that high-power transformers can be removed from the PS without significant deterioration of network-voltage quality, which makes it possible to reduce the cost, weight, and dimensions of electrical equipment.