Research On The Characteristics Of Traction Power Supply And Its Impact On Signal Equipment In The Big Station Yard

With the development of high speed railway in China, in order to meet the requirement of high speed railway transportation, railway station field is bigger and bigger, return status of return system is becoming more and more complex. In some large station yard, There is a lot of return current problems that traction return is not unobstructed and rail potential is too high, in particular, when the Overhead Contact System Pole (OCS Pole) gets into short circuit, the above problems are more serious. And the railway station is a public gathering place of power traction system and light-current signal system, so light-current signal system will be affected by the power traction system. This paper will study the influence of short circuit of OCS pole on adjacent signal cable to reflect the influence of the short circuit of OCS pole on the signal equipment.Firstly, the return system of railway station and the OCS Pole gets into short circuit models are established by using the grounding analysis software CDEGS in this paper. The characteristics of traction return of traction return system of two states that normal operation of the train and the OCS Pole gets into short circuit are analyzed. Based on the simulation results, both of normal operation of the train and the OCS Pole gets into short circuit, only a small number of boosting cable working, other boosting cables almost does not work, thus leading to the rail has high traction current; when the sole OCS Pole gets into short circuit, due to short circuit current can only flow into the earth, so there are safety problems around the OCS Pole, such as excessive ground potential.Secondly, according to the characteristics of traction return and the existence of the traction return system. Under the premise of not affecting the normal operation of the station return system, corresponding improvement measures for traction return system are proposed. The proposed optimization scheme is added to the model of the traction return system, and simulation analysis is conducted. Based on the simulation results, under normal operating conditions, the problem of the traction return system is obviously improved after adding the improvement measures. And when the sole OCS Pole gets into short circuit, can greatly improve the security after adding the improvement measures.Finally, through analysis the simulation results, it have greatest effect on Signal equipment in the signal system when short circuit of OCS in the middle of station yard. And the signal cable is a bridge connecting the power traction system and light-current signal system, so in order to research on the influence of the station return system on the signal equipment conveniently, the paper will research effect of short circuit of OCS on signal cable. The model of OCS Pole that is solely grounded is built, and distribution of related potential of cable is obtained by simulating and analyzing the OSC Pole when it is get into short circuit. And the influence rules of soil resistivity and other factor on withstanding voltage of cable are researched, by which the graph of safety critical value changes about soil resistivity and other factors are made. Finally, because of the limitation of situation on station yard, it is found that only reducing the short current conducting to the ground through sole OCS Pole can purpose of reducing voltage on cable be achieved. Based on the above analysis, two solutions are proposed and the results indicate that both of solutions can sharp decrease the withstanding voltage on signal cable and the solution 2 is better, at the same time both of solutions can be widely used in railway station yard.