高速铁路轨道的波阻抗及影响因素研究

高速铁路轨道在雷击或故障冲击电流作用下会产生暂态冲击过电压,该过电压的大小由轨道的波阻抗决定。通过建立高速铁路线路的仿真模型,分析直角冲击波在轨道上的传播与折反射过程,提出轨道的波阻抗的计算方法,研究钢轨类型、土壤电阻率、钢轨对地过渡电阻对波阻抗的影响。结果表明:P60型轨道波阻抗数值为235. 55Ω;轨道的波阻抗主要受钢轨类型和土壤电阻率的影响,高速铁路轨道的波阻抗在在210～250Ω变化;在高速铁路轨道仿真模型中,线路末端电阻等于波阻抗时,可以有效地消除折反射对仿真结果的影响,末端电阻的取值不需要考虑钢轨地过渡电阻的影响。研究给出高速铁路轨道波阻抗的范围及仿真模型中末端电阻的取值方法,可以为轨道过电压计算、分析与仿真提供理论与方法参考。

Study on Wave Impedance and Influence Factors of High-Speed Railway Track

The high speed railway track is likely to produce transient impulse overvoltage under the action of lightning or fault shock,and the overvoltage is determined by the wave impedance of the track. By establishing a simulation model of high-speed railway line,this paper analyzes the transmission and reflection process of right angle shock wave on the track,proposes the calculation method of the wave impedance of the rail,and studies the influence of the steel rail type,soil resistivity and transition resistance of the steel rail on the impedance of the waves. The results show that the impedance of P60 is235. 55Ω,the wave impedance of the track is mainly affected by rail type and soil resistivity,and the wave impedance of high-speed railway tracks varies between 210 Ω and 250 Ω. In high speed railway track simulation model,when the resistance at the end of the line is equal to the wave impedance,the impact of the fold reflection on the simulation results can be effectively eliminated; and the valuing of end resistance does not need to consider the influence of rail transition resistance. In this paper,the range of rail wave impedance and the valuing method of end resistance in the simulation model are given,which can provide theoretical and methodological references for the calculation,analysis and simulation of overvoltage.