船舶中压电网高阻接地方式机理研究

摘要

高阻接地方式用于船舶中压电网时，对其机理和规律迄今还缺乏定量研究。在对船舶中压电网单相接地故障进行理论分析的基础上，以一个具有励磁电压控制及柴油机调速的单机系统为例，结合Simulink暂态仿真，研究阻抗比、发电机频率偏移、燃弧时刻角以及故障点过渡电阻等对熄弧恢复电压、重燃过电压、中性点位移电压以及故障电流的影响。结果表明：随阻抗比增加，熄弧电压恢复过渡时间越长，恢复电压峰值越大，重燃过电压也越严重；提高阻抗比可减小故障电流，但减小程度逐渐趋缓，还会使重燃过电压增加；发电机频率偏移可能会引起较大的暂态过电压；燃弧时刻对故障电流几乎没有影响。最后给出高阻接地方式的一般配置原则。%When High Resistance Grounding(HRG)is used for shipboard Medium Voltage(MV)power grid,the mechanisms and laws can be quite complicated,which so far lacks quantitative research. Based on the theoretical analysis of single-phase ground fault for shipboard MV power grid,and taking a stand-alone system with diesel engine and excitation voltage control as example,this paper studies the HRG in detail combined with Simulink transient simulation. The research mainly focuses on the impact of impedance ratio of HRG on arc-extinct recovery voltage,re-strike overvoltage,neutral displacement volt-age,and fault current. In addition,the effects of generator frequency offset,arc angle,and fault transition re-sistance are also discussed. The results show that with the increase of impedance ratio,the longer the time of arc-extinct recovery voltage is,and the higher the peak of arc-extinct recovery voltage,the more seri-ous the re-strike overvoltage is. Increasing the impedance ratio could decrease the fault current,but the degree will slow down gradually. The generator frequency offsets can lead to greater transient overvoltage, while the arcing time angle has little impact on the fault current. At last,the general principle of HRG con-figuration is given.