双边供电下的钢轨电位影响因素及抑制措施分析

Influencing factors and suppression measures of rail potentials under the bilateral power supply

双边供电方式能够实现长距离无分相贯通供电,与单边供电方式相比系统牵引回流特性有差异,进而将导致钢轨电位分布不同,故需对双边供电方式下的钢轨电位进行研究。基于双边供电复线牵引网模型,推导了系统钢轨电位及轨中电流计算过程,通过分析钢轨电位的影响因素提出双边供电复线牵引网钢轨电位的抑制措施。研究结果表明:单边供电与双边供电取流点附近的钢轨电位基本一致,但双边供电方式下会在牵引变电所处造成更低的钢轨电位。双边供电方式下,钢轨电位在机车取流处达到最大值,取流点两侧钢轨电位逐渐减小,当上下行机车位置关于相邻变电所区间中点对称时,该区间内钢轨电位分布几乎一致,机车越靠近相邻变电所区间中点钢轨电位越大,列车运行组织应尽量避免机车在靠近两相邻变电所区间中点会车。轨地过渡电阻3Ω·km增大到15Ω·km时,钢轨电位最大值从52.49 V增大到109.01 V,增幅为107.68%,可通过降阻达到钢轨电位抑制效果。土壤电阻率从10Ω·m增加到200Ω·m时,牵引变电所处的钢轨电位从10.82 V增加到36.74 V,增幅为239.56%。钢轨电位分析与治理需充分考虑线路周围土壤条件。增设贯通地线后,机车取流处钢轨电位迅速降低,抑制钢轨电位效果显著。

The bilateral power supply method can realize the long-distance and non-phase separated through power supply,as compared to the unilateral power supply method.The traction return current characteristics of the system are different,which could lead to different rail potential distribution;therefore,it is necessary to study the rail potential of the bilateral power supply method.Based on the model of bilateral power supply multiplex traction network,the calculation method of system rail potential and current in rail was derived,and the suppression measures of rail potential in bilateral power supply multiplex traction network were proposed by analyzing the influencing factors of rail potential.The results of the study show that the rail potentials near the current pickup point of the unilateral power supply and the bilateral power supply are basically the same,but the bilateral power supply method will cause lower rail potentials at the traction substation.Under the bilateral power supply mode,the rail potential reaches the maximum value at the locomotive picking up current.The rail potential on both sides of the picking up current point decreases gradually,and the rail potential distribution is almost the same when locomotives on the up line and down line are symmetrically located about the midpoint of the zone of neighboring substations.The closer the locomotive is to the midpoint of the zone of neighboring substations,the larger the rail potential is.The train operation organization should try to avoid the locomotive meeting close to the mid-point of two traction substations.The maximum value of rail potential is from 52.49 V to 109.01 V when rail-ground transition resistance increases from 3Ω∙km to 15Ω∙km,with an increase of 107.68%,and the effect of rail potential inhibition can be achieved through the reduction of resistance.When the soil resistivity increases from 10Ω∙km to 200Ω∙km,the rail potential at the traction substation increased from 10.82 V to 36.74 V,an increase of 239.56%,and the analysis and management of the rail potential need to take the soil conditions into full consideration.After the installation of additional through ground line,the rail potential at the locomotive taking the flow is rapidly reduced,which is an obvious effect of the installation of additional through ground line in suppressing the rail potential.