A switched-mode unit used in electric locomotive generates a strong high frequency conducted electromagnetic interference (EMI),which radiates electromagnetic energy through railway lines.Evaluation of magnetic field ...A switched-mode unit used in electric locomotive generates a strong high frequency conducted electromagnetic interference (EMI),which radiates electromagnetic energy through railway lines.Evaluation of magnetic field using analytical technique based on contour integral is presented,in order to assess the electromagnetic environment around a high-speed railway.Actual railway multiconductor finitely long overhead lines are represented by an infinitely long single line above two-layered earth,whose characteristic is different from homogeneous earth.Owing to the constraint of the GB/T 24338-2009 and the high frequency investigated (a few MHz),only the magnetic fields are examined.The magnetic fields consist of four components:the direct wave,the ideal reflected wave or image wave,the trapped surface wave,and the lateral wave.The calculation results proved that due to the presence of the trapped surface wave,the magnetic field of the observer point on the interface is strongly influenced,when the line is on or closed to the interface.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.50877070 and 51105331)the Technological Research and Development Programs of the Ministry of Chinese Railways(Nos.2009J006-L and 2010J011-E)
文摘A switched-mode unit used in electric locomotive generates a strong high frequency conducted electromagnetic interference (EMI),which radiates electromagnetic energy through railway lines.Evaluation of magnetic field using analytical technique based on contour integral is presented,in order to assess the electromagnetic environment around a high-speed railway.Actual railway multiconductor finitely long overhead lines are represented by an infinitely long single line above two-layered earth,whose characteristic is different from homogeneous earth.Owing to the constraint of the GB/T 24338-2009 and the high frequency investigated (a few MHz),only the magnetic fields are examined.The magnetic fields consist of four components:the direct wave,the ideal reflected wave or image wave,the trapped surface wave,and the lateral wave.The calculation results proved that due to the presence of the trapped surface wave,the magnetic field of the observer point on the interface is strongly influenced,when the line is on or closed to the interface.
