Influence of DC Grounding Mode on DC Fault Characteristics in Ship Medium Voltage Power System

At present, in the background of the multiphase rectifier system is widely used in medium voltage ship power system, the influence of DC grounding mode on the characteristics of DC monopole fault is analyzed for series 12-pulse uncontrolled rectifier system and paralleled 12-pulse uncontrolled rectifier system respectively. By establishing the electromagnetic transient model of the medium voltage power system under different topologies, fault voltage, recovery speed and fault current under different grounding modes are simulated and studied, and the fault mechanism is deeply analyzed, and the advantages and disadvantages of different grounding modes are compared. As a conclusion, for series 12-pulse rectifier system, the way of high impedance grounding through the middle point of the two series rectifier bridges is proposed. For paralleled 12-pulse rectifier system, high resistance grounding mode through the middle point of split capacitances on dc side is proposed, they are beneficial to improve the stability and transient performance of the system. That it is beneficial to improve the stability and transient performance of the system. (paper)