Field Measurement of Surface Polarization Voltage Around Guangzhou Metro

At present, the development of subway in China is very rapid, which brings great convenience for people to travel. However, because the subway is not completely insulated from the ground, stray currents can be generated. A measurement scheme was designed to measure the actual geodetic polarization voltage of line 4, Science City and Jinfeng metro line 6 of Guangzhou Metro. The effect of stray current on geodetic polarization voltage is studied. The results show that the potential around the subway system fluctuates all the time. The polarization voltage around the subway is related to the current position of the subway. Moreover, it has been proved that the stray current of subway can affect the geodetic polarization voltage. The polarization voltage caused by stray current can be as high as tens to hundreds of volts.