ABSTRACT
With the development of science and technology and urbanization, traffic is becoming more
and more important in today’s life. In China, the subway is rapidly developing as an important
transportation tool for the city. However, in the metro subway transportation system, it is generally
used Because of the restriction of the operating environment and other factors, the DC power
traction power supply cannot completely isolate the ground facilities. Therefore, the return rail has a
certain leakage current to the ballast, surrounding soil medium, underground building, and buried
pipeline, and the current is negative. The feedback point (that is, the substation) is back along the
underground structure, buried pipelines and other media back to the route, this leakage current is
"Stray flow of the subway", commonly known as "Metro fans." Due to the electrochemical
corrosion of the steel bars in the buried metal pipes, the outer part of the communication cable metal
armored steel and the main structures of the station and the section tunnel, the stray current can not
only shorten the service life of the metal pipe, but also reduce the strength of the metal pipe. The
main structure of the subway is reinforced concrete, stray current will also reduce its durability, and
even lead to catastrophic events. In addition, the subway structure has been finalized after the
completion of the construction. It is very difficult to modify the main structure after several years of
operation. Therefore, it is necessary to monitor and protect the stray current of the subway.
This paper first describes the causes, types, and hazards of stray currents in urban rail subways.
The corrosion mechanism of stray currents is derived by analyzing the mechanism of metal
corrosion. Finally, the status quo of stray current protection and monitoring at home and abroad is
analyzed to investigate stray currents. Protection measures and their implementation.
【Key words】urban rail subway stray current monitoring protection
