Simulation And Dynamic Simulant Display Technology Of Electromagnetic Field Distribution In Urban Rail Transit Station

After decades of development,urban rail transit(URRT)has already played a positive role in improving the quality of people's life and regional economic development,because of its advantages such as large capacity,high efficiency,low energy consumption,and so on.Complex power system is adopted in urban rail transit,and a large number of electrical and communication equipment are gathered in the station building,and their electromagnetic radiation contributes significantly to the station's inner electromagnetic environment.Whether it will cause harm to the health of passengers or operators,or improve interference risk to the equipment in the URRT system,are worthy of research.In this thesis,the electromagnetic field distribution of the URRT station platform and communication equipment room and the electromagnetic environment monitoring technique are studied.These studies can provide technical means and data basis for evaluating the electromagnetic environmental friendliness of the URRT system.The main contents and achievements of the work are as follows.Based on the analysis and field survey of the characteristics of the URRT system,the electromagnetic environment and the main disturbance in the platform and communication equipment room are described in detail,and the typical disturbance sources with its transmission routes are discussed.The geometry model of URRT platform(including part of tunnel)is built according to the site investigation.Characteristics of electromagnetic field distribution in different cross sections and longitudinal sections of platform are simulated and analyzed,considering the radiation sources such as the ceiling communication antennas,the trackside antennas and the rail currents.The wireless signal coverage in the platform waiting area and the tunnel area satisfies the required uniformity when the radiation sources are ceiling communication antennas and trackside antennas,and the field intensity is under the limit of the public exposure electromagnetic field.When the harmonic component value of rail current value is large,part area's magnetic field intensity caused by it may exceed the limits of the public exposure electromagnetic field.The simulation model of underground and above ground(elevated)communication equipment room of URRT are built respectly.The simulation of magnetic field distribution shows that the low frequency magnetic field intensity near wall and antistatic plastic floor is larger than center area,when the typical radiation source is under the room's antistatic plastic floor.The high frequency electromagnetic field caused by the outside motor vehicle ignition noises are simulated and the result shows the changes related to the quantity of the noise sources and the arrangement of their position.The electric field intensity and distribution characteristics in the elevated communication equipment room are influenced significantly by these factors.A magnetic field measuring system is proposed to perform monitoring of the electromagnetic environment in the communication equipment room.The Lab VIEW virtual instrument controls towards two type of magnetic field probes are developed and tested in order to meet the monitoring requirements.This work realizes the dynamic acquisition of the magnetic field intensity.And furthermore a demonstrated twodimensional field distribution of the sampling height plane can be displayed dynamically.