Simulation Of High-altitude Nuclear Electromagnetic Pulse Current Injection In Traction Network

With the development of China’s economy,the role of railway system in national production and life is becoming more and more important,and traction power supply system is one of the first conditions to ensure the smooth and efficient operation of the railway system.However,with the development of power electronic technology,the electromagnetic environment of the traction power supply system is becoming more and more complex,especially with the development of various electromagnetic pulse generation devices towards the direction of miniaturization and portability,which makes the electromagnetic environment of the internal space of electric locomotive become more and more severe.Therefore,it is necessary to study the electromagnetic pulse interference test technology of traction power supply system,which is of great significance.Firstly,this paper introduces the electromagnetic environment of hemp and a new hemp current source which adopts mil-std-188-125 standard of the U.S.Army.Based on the former hemp generator,the structure of the current source is improved so that it has the characteristics of miniaturization,mobility and adjustable polarization direction compared with the former EMP generator.Then,the injection effect of hemp on the traction power supply network is analyzed and calculated by using the transmission line theory.By analyzing the actual situation of the traction power supply network,the transmission line calculation of the transient response of the whole traction power supply system which can be simplified as the nonlinear load of the semi free space nonlinear load is obtained,and the electric locomotive is simplified as the nonlinear load,and the conductor of the traction network is simplified The results of hemp current injection response under the model.Secondly,the mathematical model of the main components of the traction power supply system is established,including traction substation,traction network conductor,electric locomotive and lightning arrester.This paper introduces and analyzes the relationship between the current and voltage of the traction substation under different connection modes,the advantages and disadvantages of the railway power supply system under different power supply modes,and the scenarios of its use.For the multiple conductors with complex spatial position in the traction network,the combination and simplified calculation of these conductor parameters are realized by using Carson theory and matrix transformation method,and the control flow of the electric locomotive operation is carried out Analysis and introduction.At the same time,based on the mathematical model of traction power supply system,the simulation module of traction power supply system and hemp current source using at power supply mode is built by PSCAD simulation software.At the same time,the simulation results of each module are compared with the relevant standards to verify the correctness of the simulation module.At last,the simulation system is used to simulate the different wires injected into the traction network by hemp current source At the same time,the over-voltage amplitude and waveform of each observation point are compared when different wires are injected into each observation point,and the change of the over-voltage amplitude and waveform of each observation point after adding the arrester is simulated.The results show that when hemp current is injected into the catenary and the positive feeder,similar overvoltage will occur,and the amplitude of overvoltage will increase greatly;when hemp current is injected into the rail,the overvoltage is not obvious;after adding the arrester,the overvoltage amplitude can be effectively suppressed,but there is still a relatively serious residual voltage,which is very harmful to the electric locomotive and traction network.