Study On The Traction Current Interference Protection Of Track Circuit Equipment

In recent years,electrification,High-Speed and Heavy-Haul Railway developed rapidly in China.Nevertheless,the trend of increasing speed and load means larger traction current which is provided by traction power supply system.Also,due to the fact that traction current and signal current of track circuit share the same track as their transmission path,it leads to the phenomenon that the interference caused by traction current has severer impact on track circuit,which is an essential component of railway signaling system.Therefore,it is of great significance to explore the mechanism of interference caused by traction current to track circuit equipment and take feasible measures to prevent interference originating from traction current.Based on this situation,the main work of this paper are as follows:Firstly,according to the three elements of EMC,the analysis concerning the influence of the traction current on the track circuit is carried out from three aspects,including the interference source,the coupling path and the susceptible equipment.With the sorting out of main interference sources of the track circuit,the coupling path of the traction current,and the effect of the traction current on the track circuit,the corresponding results are obtained.The above research and analysis confirm the interference mechanism of the traction current,which enables the establishment of traction current interference model of track circuit.Secondly,with the foundation of the above research,a simulation model of traction current interference based on the four-terminal network theory is proposed for ZPW-2000A type jointless track circuit.The model considers the effects of different parameters of track circuit(such as ballast resistance,unbalanced coefficient etc.),which may calculate the receiving terminal voltage in the state of normal,the residual voltage of receiving end in the state of shunting and locomotive signal current.The comparison between the measured data and the simulation data verify the validity of the simulation model.Lastly,the established model is utilized to verify the effectiveness of the anti-interference measures of the traction current interference.With combination of the model and the field practice,two kinds of maneuverable anti-interference measures are confirmed.According to the reality that there exist different environmental conditions,which are not taken into account in the adjustment table used in the railway field,one strategy weighs various factors from maifold perspectives,optimizes the transmission voltage and the attenuation coefficient of the adjustment table and then achiecves the anti-interference purpose.Another anti-interference strategy adopts the thought of active filter,which is a supplementary strategy for the first strategy under the condition that the interference harmonic amplitude is higher thus the anti-interference effect is not ideal.The first scheme has already been applied in the railway field and has achieved a satisfactory application result.