高速铁路典型牵引变电所回流异常分析与抑制方案研究

Study on Abnormal Analysis and Inhibition of Return Current in Typical Traction Substation of High-speed Railway

基于我国高速铁路部分牵引变电所存在牵引回流异常,地网回流占比长期偏大,可能加剧地网结构腐蚀甚至烧损金属接头组件的现状,根据高速铁路牵引供电系统等效牵引回流模型,给出考虑牵引变压器接地端子与钢轨间连接线缆(N线)影响的不同位置钢轨电位和电流计算公式。分析N线阻抗变化对牵引回流的影响。结合实际工程案例,得到不同设计参数下牵引回流分布规律,找出变电所地网回流过大的原因,并有针对性地提出抑制方案。最后对比工程整改前后的差异,验证了上述模型分析和解决方案的正确性。

In view of the abnormal traction return current in some traction substations of high-speed railway in China and the excessive return current of the ground grid,which aggravates the corrosion of the structure of the ground grid and even damages the metal joint components,this paper offers calculation formulas of rail potential and current at different positions considering the influence of the connection cable(N wire)between the grounding terminal of traction transformer and the rail according to the equivalent traction backflow model of high-speed railway traction power supply system.Then,the influence of the impedance change of the N wire is analyzed.Afterwards,combined with practical engineering cases,the distribution law of traction return current subject to different design parameters is obtained,the reason of oversize backflow of substation ground network is found out,and the suppression scheme is proposed.Finally,by comparing the differences before and after the engineering rectification,the correctness of the above model analysis and solution is verified.