Modeling And Simulation Of ZPW-2000A Jointless Track Circuit

Red belt, poor shunt and broken rail is a common fault of the track circuit, a serious threat to the operation of the train safety and effect on the operation efficiency of the train.These three faults leads to track circuit working mistakes respectively: regulated state,shunted stated and broken rail stated. As the ZPW-2000A jointless track circuit is added with electrical insulation, compensation capacitors and other instruments on the basis of traditional track circuit, conclusions of the original traditional track circuit can not be fully applied to ZPW-2000A jointless track circuit. At present, there are still some shortcomings in the study of ZPW- 2000A jointless track circuit in the state of breaking rail. Therefore,through the study of signal transmission theory, the establishment of three basic state of the jointless track circuit modeling and the simulation of them, finding out the corresponding influence on the signal transmission from each failure working state, are significant to the track circuit’s routine maintenance, location of faults and fault fixing.The paper was presented as following:Firstly, this paper introduces the research progress and research significance of the development of track circuit at home and abroad and analyzes the structure of ZPW-2000A jointless track circuit, the working principle of electrical insulation section. Based on these,the model of matching transformer, compensation capacitor, air-core coil, analog cable,SPT digital signal cable, T-type transmission network of transmitter and receiver T-type transmission network are established. Finally, The corresponding state signal transmission model can be obtained by cascading four-terminal network model according to the actual track structure working in regulated state of a track circuit, shunted stated of a track circuit and the broken rail state of the main track and the broken rail state of small track in the tuning area.Secondly, designing ZPW-2000Ajointless track circuit simulation software which includes the simulation software structure, human-computer interaction interface and related state data processing can display of three basic track circuit statea, corresponding operation design, and correlation curve.Finally, the simulation and analysis of influencing factors are made under the regulated state, shunted stated, the main rail breaking state, and the breaking state of small track in the tuning area. This paper analyzes the factors that affect the regulated state of a track circuit, such as compensation capacitance, ballast resistance change, compensation capacitor fault, compensation capacitor fault offset, and the effect of hollow coil fault on the signal transmission under the condition of regulated state. The residual pressure under different shunt positions and ballast resistance is analyzed; the shunt current and shunt residual voltage are simulated. In additon, the residual pressure of the main track is simulated with different position and ballast resistance, and then the simulation analysis is carried out for the small residual voltage of the track in the end of the transmission area,which proves that the main track circuit of ZPW-2000A jointless track circuit can not check the broken rail without the small track circuit. Therefore, Only by installation of small track circuit can whole process broken rail inspection be achieved.