| With the development of human science and technology,there are many ways for people to travel,and the means of transportation become more intelligent.As a way of railway transportation,it is always the goal for people to improve the speed safely and reliably.However,it is very difficult for ordinary wheel rail trains to continue to grow.Therefore,the high-speed and constant guide maglev train supported by maglev technology is close to In recent years,it has attracted the attention of many countries.Maglev train is a complex electronic power system,which has no contact with wheel rail during high-speed operation,and there is no protective shielding measures similar to EMU above the train,and the grounding structure is also quite different from ordinary wheel rail train.When the maglev train runs along the elevated line,it is easy to be damaged by direct lightning.The complex and precise measuring,monitoring,communication and electronic equipment equipped on the train will have a huge impact and cause immeasurable losses when it is damaged by direct lightning.Due to the wide range of lightning spectrum,huge power,multiple paths of electromagnetic penetration,pulse energy is almost impenetrable,which seriously threatens the normal operation of the train equipment and thus endangers the safe operation of the maglev train.During the normal operation of on-board electronic equipment,due to the influence of lightning electromagnetic pulse,induced current and induced voltage will be generated on the internal cable,which will cause different degrees of damage to on-board equipment.In order to improve the lightning protection ability of high-speed maglev train,the lightning attachment point and separation point of maglev train are simulated and analyzed to determine the injection point of lightning current on the vehicle body and the lightning current discharge point in case of over-voltage breakdown of the vehicle body.On this basis,the electromagnetic simulation software is used to analyze the cable type,cable shielding layer grounding mode,cable position,etc.of high-speed maglev train under the use of lightning current The influence of the coupling characteristics of the induced voltage and current of the cable.Finally,the cable coupling experiment platform of high-speed maglev train is built.According to the pulse current method in SAE ARP 5416,the coupling characteristics of maglev train cables under lightning current are studied.The experimental results are basically consistent with the theoretical simulation analysis.The main research results are as follows:(1)The transient field coupling model of lightning electromagnetic pulse is analyzed.Based on four field line coupling methods,the induced voltage and induced current of lightning electromagnetic pulse on the cable are derived.The formation mechanism of lightning and the whole physical process of lightning hitting maglev train are analyzed theoretically.(2)Based on the Electromagnetic simulation software,the transient electromagnetic environment of maglev train is simulated to determine the lightning attachment point and separation point of maglev train.This study is helpful to analyze the whole physical process before lightning strikes the vehicle body and determine the lightning current discharge path.(3)Theoretical analysis,simulation and experimental research are carried out on the indirect effects of lightning stroke such as cable coupling voltage and current caused by lightning stroke on high-speed maglev train.The research results show that: the location of cable close to the vehicle body,the selection of twisted pair and the way of shielding cable double terminal grounding can effectively suppress the cable coupling current inside maglev train.The whole research on the lightning of maglev train The protection of indirect effects laid the foundation. |
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