Power Quality Analysis In Electric Propulsion Ship

Electric propulsion for its excellent operational, high economy, stable and reliable performance characteristics, will become the next widely used means of advanced propulsion way. Power capacity of the electric propulsion ship power system is relatively limited and as an independent power grid. The grid voltage fluctuation, sag, flicker, etc power quality question can be caused by non-linear, pulse load and other electrical equipment, as well as the environmental factors, and thus a direct impact on other sensitive equipment. Effective analysis of the ship power system power quality, protection of sensitive equipment, normal operation of the system and other issues is basis of the system designing, resources optimization and increasing system reliability, and it is conducive to the ship's power system power management,so that power supply unit work in efficient area.In this paper, with characteristics of electric propulsion ship, first introduced the composition of its power system. According to the modular idea, the power system is divided into electricity, and electricity transmission and distribution of three systems, analysis the electrical characteristics, and work principle of major equipment of each system. Establishing the mathematical model of these facilities and base on the models, to analysis power quality phenomuon in power system.Power supply system focused on its core, synchronous generators, a detailed analysis of the diesel engine and the speed control system, generator and its excitation control system, and give the corresponding mathematical model,then verify the accuracy of the model and analysis power supply quality problems; Transmission and distribution system mainly introduce the working principle of the main switchboard, and analysis its role in the electricity power distribution; Electricity system, mainly introduce asynchronous motor and synchronous motor and their SVPWM frequency control devices, respectively, establish their mathematical models and simulation models, analysis the voltage quality problems caused by the change of load and faults, using the FFT to reserach harmonic problems of the electric propulsion system.Finally, given a simplified system that is a single generator-single propulsion motor simulation system model. Studied the induction motor due to voltage sag, pulse disturbance caused by short-circuit fault, harmonic distortion and other power quality phenomena. Combination the power system configuration of an electric propulsion ship of China, verify the simulation model built the accuracy and applicability, and research the voltage transient, harmonic pollution, the phenomenon of power quality in the electric propulsion system. And analyzing the causes for the latter part of the assessment of power quality and control to provide the basis.