船舶中压直流电力系统接地方式对直流纹波影响研究

Influence of Grounding Mode on DC Ripple in Ship MediumVoltage DC Power System

单相接地故障作为一种常见电气故障,会使船舶中压直流电力系统的直流电压纹波产生畸变,影响系统正常运行。以中压直流电力系统的单相接地故障为背景,研究了整流发电机中性点接地方式对纹波的影响。首先运用对称分量法和开关函数法,分别计算了直流电压的正常纹波次数与故障下纹波次数,并推导出故障下直流电压中交流分量的解析表达式。然后,通过分析绕组间的零序回路,得出了故障绕组零序电压与接地方式之间的关联,从而进一步得到接地方式对直流纹波的影响。最后,通过PSCAD与MATLAB/Simulink仿真软件搭建模型,进行仿真验证,为舰船中压直流系统整流发电机接地方式的选取提供参考依据。

As a common electrical fault,single-phase grounding fault will distort the DC voltage ripple of ship medium voltage DC power system and affect the normal operation of the system.Taking the single-phase grounding fault in medium voltage DC power system as the research background,we study the influence of neutral grounding mode of rectifier generator on ripple.Firstly,using the symmetrical component method and the switching function method,the normal ripple order of DC voltage and the ripple order under fault are calculated respectively,and the analytical expression of AC component in DC voltage under fault is derived.Then,by analyzing the zero sequence circuit between windings,the correlation between the zero sequence voltage of fault winding and grounding mode is obtained,which can be used to further study the influence of grounding mode on DC ripple.Finally,the model is built by PSCAD and MATLAB/Simulink simulation software for verification.This research can provide a reference basis for the selection of grounding mode of rectifier generator in ship medium voltage DC system.