Electromagnetic Interference Analysis Of Train Speed Sensor Radiated By Pantograph-Catenary Arc

The offline operation of the train pantograph and catenary is prone to arc discharge,accompanied by strong electromagnetic radiation,which endangers the electromagnetic safety of sensitive equipment in the railway system.The speed sensor is one of the most important electronic devices in trains.In the arc radiation environment of the pantograph network,it is easy to be affected by the arc radiation interference of the pantograph network and cause faults.Due to the complex actual working conditions of trains,it is very difficult to conduct electromagnetic interference testing of speed sensors on trains in operation.Therefore,utilizing the inherent advantages of numerical methods for repeated simulation,we will conduct electromagnetic simulation of large-scale and multi-scale spatial electromagnetic radiation field distribution of trains,speed sensor cable crosstalk and coupling,and speed sensor pantograph network arc radiation interference.We will grasp the propagation mechanism of speed sensor pantograph network arc radiation interference and provide technical support for fault recurrence and diagnostic analysis of speed sensors.The main work of this article is summarized as follows:(1)Research on Electromagnetic Radiation Characteristics of Train Bow Net Arc.The high-voltage cable car body model,catenary pantograph model and pantograph catenary car integrated coupling model are established.The electromagnetic radiation mechanism of the pantograph catenary arc conduction through the catenary,pantograph and traction return circuit is simulated and analyzed,and the space-time distribution characteristics of the pantograph catenary arc radiation field inside and outside the train,the train body overvoltage,the vehicle body grounding circuit overvoltage and other important data are mastered,To lay the foundation for the subsequent analysis of arc radiation interference from speed sensors,pantograph and catenary.(2)Calculation of bow net arc radiation coupling for speed sensor cables.Firstly,a calculation method for the transfer impedance of braided shielded cables was studied,and the transfer impedance of speed sensor cables covering the arc radiation frequency band of the pantograph network was obtained;Then,using the transmission line equation,an electromagnetic coupling model of the single-layer shielded cable for the speed sensor was constructed,and the core response of the shielded cable was solved using the FDTD method;Finally,the shielding performance of double-layer shielded cables was analyzed from the perspective of magnetic field energy,and the electromagnetic coupling characteristics of double-layer shielded cables were simulated and analyzed,which has theoretical guidance significance for improving the shielding efficiency of speed sensor cables.(3)Analysis of bow net arc radiation interference of speed sensors.Using the train body as the carrier,a coupling simulation model for the overvoltage conduction of the speed sensor and a coupling simulation model for the arc radiation of the pantograph network were constructed.Through field circuit collaborative simulation,the transient response of the speed sensor core under the action of the vehicle body overvoltage and the space arc radiation field of the pantograph network was mastered,in order to evaluate the electromagnetic safety of the speed sensor in the arc radiation environment of the pantograph network.