Analysis on Rail Potential Distribution Characteristics Considering OVPD in Metro System

By the field investigation of the metro system, it is found that there is relatively serious corrosion in the terminal of the metro line, and overvoltage protection device (OVPD) often operates when the metro system is in the valley level. In order to analyze the causes of these conditions and alleviate the related problems caused by high rail potential. In this paper, establish a simulation model of metro system by CDEGS software, and consider the influence of the track-to-track cross bond on rail potential. It is analyzed that the causes of high rail potential in the terminal of the metro line and high rail potential operating small number of trains in the metro line. And it is analyzed that the influence on the rail potential of metro line, the influence on OVPD outside the power supply section, the influence on the station grounding gird where the OVPD is, caused by OVPD operation. The results show that the rail potential can be reduced to some extent by setting the track-to-track cross bond. No traction power substation (TPS) in the terminal of the metro line increases the rail potential. When the braking train supplies power to the accelerating train outside the power supply section in the metro line, the rail potential of some part of the line increases. The OVPD operation increases the ground potential around the station grounding gird, and may lead to the continuous operation of other OVPD in the metro line.