—The potential limiting device has been adopted in the operation metro, by observing the running metro, we found the rail voltage in the process always maintain a high value, which results in traction substation, OVPD keep closing state, this situation leads to the stray current leakage increases, increases the stray current produced harm. Therefore, more effective optimization control of OVPD, can effectively reduce the rail potential, decrease the effect of stray current. In single interval and multi interval, this paper will analyze the rail potential under different conditions that two OVPD closing or opening which are installed in two substations .
