Simulation on adjacent line mutual interference of high-speed railway track circuit

As the density of the high-speed railway network continues to increase, the problem of electromagnetic interference on adjacent lines has become increasingly prominent. This paper focuses on the electromagnetic interference of adjacent lines caused by rail and line in the signal transmission process of the high-speed rail track circuit. Firstly, complete the establishment of the four-terminal network model of the ZPW-2000A track circuit system and the cab signal entry current crosstalk model, calculation of interference voltage under different parallel length of signal frequency. Then the interference factors and coupling mechanism of adjacent lines are analysed to realize calculation of interference amount. Finally, according to the sensitivity index of the cab signal, the maximum parallel length of adjacent sections is given respect, and the interference protection suggestions of adjacent lines are put forward. The research work of this paper provides a theoretical basis for suppressing the interference of adjacent lines and guarantees the safe and efficient operation of high-speed trains.

Calculation of Rail Impedance of Track Circuit Considering Earth Stratification

Rail impedance directly affects the transmission performance of track circuit . Considering the condition of earth stratification, for the difficult to calculate the rail impedance due to the semi-infinite integration interval and the oscillation of the integrand by using the Carson formula, The truncation method is proposed to divide the impedance formula is divided into definite integral and tail integral. The integral is approximated by the spline function, and the tail integral is calculated by using the exponential integral and Euler formula. Based on it, the rail impedance calculation formula of track circuit is obtained. The electromagnetic field model of track circuit with earth stratification is simulated by finite element method, and the correctness of the method is verified. Based on the formula, the influence of current frequency, soil depth and conductivity on rail impedance is studied. The relative error between the calculated results of rail impedance and the simulation results of finite element is within 5%. It can be seen that the formula has high accuracy and correctly reflects the law of rail impedance variation with current frequency, soil depth and resistivity. It provides a reliable reference for the theoretical calculation of rail impedance of track circuit.

Influence of geoinduced currents on impedance bonds with secondary windings used in railway automation circuits

Objective: To consider the possibility of DC magnetization of the core of the impedance bond with secondary winding when using AC electric traction. To determine the possible influence of solar activity, and in particular the geoinduced currents, on the signaling arrangements (SAs). Methods: Analysis of the conditions and causes of magnetization of the core of the impedance bond with a secondary winding, which is the reason for a decrease in its inductance and a change in the track circuit coefficient of transmission. Description of the influence of geoinduced currents on the operation of traction substation power transformers and the using this scenario for modeling the operation of impedance bonds with secondary windings. Results: The conditions and reasons for the incorrect operation of the impedance bonds with secondary windings associated with the magnetization of the core by direct current, when using electric traction with alternating currents, have been stated; the possibility of saturation of the magnetic system of the impedance bond with geoinduced current has been analyzed; the possible consequences of the transition of the impedance bond to the saturation mode have been determined. Practical importance: The study findings broaden the knowledge about the possible influence of solar activity on the railway infrastructure facilities, which in its turn is necessary for the development of methods and means aimed at ensuring the uninterrupted operation of railway transport.