[工学]广州地铁五号线杂散电流防护研究与设计.doc

摘 要 目前地铁大都采用走形轨回流的直流牵引供电方式，因而在运营中将不可避免地产生流经大地的杂散电流。地铁杂散电流严重腐蚀地下金属结构，影响地铁安全运营，因此全面考虑地铁杂散电流腐蚀问题，探讨更为有效的杂散电流腐蚀防护措施，保证地铁安全运营具有十分重要的意义。 本文首先介绍杂散电流的产生、危害及其对结构钢筋和埋地金属管线的腐蚀机理；然后分析在有无排流网设置、是否排流情况下单边供电方式和双边供电方式中杂散电流的分布规律及各个参数对杂散电流的影响，并据此讨论杂散电流的防护措施和监测手段。最后结合广州地铁五号线工程的特点，综合提出广州地铁五号线的杂散电流防护系统设计方案。 广州地铁五号线杂散电流防护方案包括设置杂散电流排流网、新型智能排流装置的杂散电流防护方法和集中式监测系统。集中式监测系统将采集结构钢极化电位、参考电极本体电位和轨道对结构钢的电压等数据上传至上位机处理，实现对整个系统进行实时在线远程监测，为地铁杂散电流防护提供参考。 关键词：地铁；直流牵引供电系统；杂散电流；腐蚀；防护 Abstract Currently, the running rails are usually used as the return conductor for DC traction power supply system in the metro. Therefore, it is inevitable that there will be current leaking into ground through the running rails, resulting in the serious corrosion to the underground metal structure and infecting safe operation of the metro. Thus, it is very necessary to fully consider the stray current corrosion issue, to explore more effective protective measures for stray current corrosion in order to ensure the safe operation of the metro. Firstly, a discussion of the cause and hazard of stray current in DC traction power supply system and the mechanism of corrosion of it to steel structure and metal pipeline are presented in this paper. Then, the regularities and distribution of stray current are analyzed at either drainage or non-drainage situation in one-way feeding and two-way feeding power supply system. And each factor that affected stray current distribution rule has been analyzed. On the basis of stray current distribution rule, the methods and measures to control and monitor stray current are discussed. Finally, according to the characteristic of construction projects of Guangzhou metro line 5, the proper stray current protection and monitoring system is designed. The stray current protection and monitoring system is composed of the protection methods of stray current such as drainage net, a news intellectual drainage arrangement and centralized monitoring system. The data such as the steel polarization pote