影响地铁牵引系统杂散电流及地表电位的因素分析OA

In order to study the formation process and relative influencing factors of metro stray current and ground potential,a simulation model of metro traction system stray current and ground potential ac-cording to the real structure of metro system is built.With the model,the influencing regularities of rail-ground transition resistance,drainage net,and structural reinforcement on stray current and surface potential are analyzed.Results show that although the rail and the earth are isolated by insulating mem-bers,the magnitude of the grounding resistance of the rail ground system is about 0.1 Ω～1.0 Ω due to the existence of transition resistance and the long length of rail,leading to the possibility of large stray current invading the earth;The stray current and surface potential decrease with the rise of rail ground transition resistance.But the further increase of rail ground transition resistance will reduce the effect of limiting stray current when the rail-ground transition resistance is greater than 15 Ω·km.It indicates that preventing the deterioration of rail-ground insulation is the key in limiting stray current;Both drain-age net and structural reinforcement can effectively reduce the stray current and ground potential.Con-necting the structural reinforcement as a whole can enhance its ability of recovering stray current,reduc-ing the influence of stray current;Besides,the return impedance of traction current will change with the metro position so that the distribution of stray current is also affected.