Study On Electromagnetic Radia Tion Interference Andprotection Measures Of Railway Arcs

The high speed of train operation is the inevitable trend of the development of electrified railway.At present,the railway train operation in the whole world is developing rapidly.The improvement of the speed of the train operation and the establishment of a higher speed railway transport network are the targets of the continuous pursuit of the development of the railway.With the high speed of train operation,the problems of power supply and receiving terminals in railway are becoming more and more serious.During the high speed operation of railway train,the vibration of the power supply end and the receiving end,the unsmoothness of the contact time,the uneven track itself,the separation between the electric terminal and the power supply end in the high speed running time of the train produces the arc.The railway arc will also produce a large amount of electromagnetism interference at the time of occurrence,which will disturb the key along the railway line.Off-line arc is one of the key problems of high-speed trains.As the electromagnetic compatibility standard of railway system is more and more strict,it is necessary to study the railway arc and put forward effective protection measures to restrain unnecessary interference.The frequency range of arc interference is derived from the electrical characteristics of the arc.The electric arc electromagnetic interference radiation is calculated by FDTD program,and the simulation of electromagnetic interference using electromagnetic simulation software is built,and effective protection measures for arc electromagnetic interference are put forward.The main research work is as follows:Firstly,starting from the basic concept of arc,the characteristics and components of arc are analyzed.The arc consists of three parts,the cathode region,the anode area and the arc column.The mathematical equation of arc formation is derived from the conservation of energy in the process of arc occurrence.The mathematical equation of arc mathematics describes a black box model of a two port,neglecting the physical changes inside the arc,only considering the external characteristics of the arc.And the arc is limited by different conditions,and the most classical physical and mathematical models of the two kinds of arcs of Mayr and Cassie are obtained,in which the Cassie model generally describes the accuracy of the arc occurring before zero,the arc current is larger,the Mayr arc describes the zero crossing time of the arc is more accurate,and the arc current is at this time.Smaller.Secondly,the mathematical equation of the arc is replaced by the simulation parameterequation,and the mathematical model of the arc is established by using the Simulink module of MATLAB to describe the equation parameters.Through the simulation of different arc models,the change relation of voltage and current at the moment of arc occurrence is obtained,and the electrical characteristics of different arc voltage and current varying with time under the action of different excitation sources(alternating current source and DC voltage source)are obtained.Finally,the arc is assumed to be a monopole antenna,and the radiation interference characteristics and frequency range of the arc are analyzed by FDTD algorithm.A train locomotive model is set up in the electromagnetic simulation software,and a protective baffle is set up for the collector shoe to reduce the radiation interference of the arc.The simulation results show that the protection measures can effectively reduce the electromagnetic radiation interference of the arc,and provide an effective reference for the safety design of railway operation.