煤矿电网谐振接地系统暂态脉冲极性的研究

Study on Polarity of Transient Pulse in Coal Mine Resonant Grounding System

通过对井下独立变电所和级联多变电所模式下发生单相接地故障时各分支路零序电流表达式的推导,文章分析了此暂态脉冲的初始幅值、脉宽持续的时间与接地电阻、线路对地分布电容、故障时刻之间的关系,并给出了相关的表达式。故障线路的暂态脉冲幅值最大且极性与非故障线路的暂态极性相反,故障时刻暂态脉冲的幅度与接地电阻成反比,与故障相位角正弦值成正比;所有非故障线路的暂态脉宽一致,且小于故障线路的暂态脉宽,暂态脉宽与接地电阻成正比。最后matlab下的仿真验证了该结论的正确性。

In order to analyze the relationships between the initial amplitude, duration of the transient pulse and the earthing resistance, the earth capacity, and fault time, the paper deduced zero - sequence current expressions when phase to earth fault oceured in single substation mode and multi - substation mode, the related expressions were also given. The result shows that, the transient pulse polarities between the fault lines and normal lines are completely opposite, and the transient pulse＇s amplitude of fault line is the largest among all the lines. Moreover, the amplitude of transient pulse is proportional to the sin of fault angle and inversely proportional to earthing resistance. Besides, all the normal lines have the same width of transient pulse, smaller than that of fault line, and is proportional to earthing resistance. And the simulation by matlab proved the correctness of these conclusions.