Distribution Characteristics Of Low Frequency Magnetic Field In Subway Train

Urbanization has led to the growing urban scale and cities population,the consequences of which is cities growing traffic congestion.As the most effective means to slove traffic problems,urban rail transit have emerged.More and more people choose subway when they go out,so the opportunity that people contact the electromagnetic is more and more.People pay more and more attention to the problem that the electromagnetic exposion threats the heath of people.This paper mainly study the characteristics of the low frequency electromagnetic of the subway.Dose the limiting value exceed ? Is it safe for people to choose? This is the mian subject of this paper.This paper mainly disscusses the harassment source of strong magnetic field:the traction system in the third chapter.In the fourth chapter paper mainly simulates the powerful cables,such as the DC110 V cables 、the medium 400 V cables、the DC1500 V cables from roof pantograph to fuse box、the DC1500 V cables from PH box、the cables from VVVF to motors and AC cables for B vehicle chassis.The safety distance that meets the standard limit is obtained by the simulation.It is also found that the larger the current value in the power cable,the stronger the magnetic field.The electromagnetic field is attenuated with the increase of the distance from the cable center.The author puts forward bold ideas.Because there is also a certain thickness of 10 cm floor layer in the middle.The electromagnetic field radiated into the interior of the carriage will not exceed the relevant standards.The assumption needs to be tested and validated.So in the fifth chapter,the electromagnetic field inside the carriage is measured by the fixed-point.With special focus on strong electromagnetic interference sources such as VVVF box,reactor,brake resistance and high voltage box,there is also the position in the compartment corresponding to the large cable coming down from the pantograph.After the test is completed,the following conclusions are drawn:The magnetic field is stronger at the point of strong disturbance source.For example,the corresponding points of the large cable coming down from the pantograph in the carriage,VVVF and reactor.And the farther from the interior floor of the,the magnetic field decreases.The measured magnetic field is slightly higher at 0.3m,but due to attenuation,the magnetic field is very small at 0.9m and 1.5m.The variation rule of magnetic field intensity is consistent with the simulation results.Distribution law of low frequency magnetic field in train is obtained by simulation and experiment.Whether it is a trailer or a motor vehicle with traction equiment on the chassis,the electromagnetic field inside the carriage will not exceed the standard.It is safe for passengers to take the subway.