Electromagnetic environment around a high-speed railway using analytical technique

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.

[1]  A. Cozza,et al.  On the Modeling of Electric Railway Lines for the Assessment of Infrastructure Impact in Radiated Emission Tests of Rolling Stock , 2008, IEEE Transactions on Electromagnetic Compatibility.

[2]  E. Sunde Earth conduction effects in transmission systems , 1949 .

[3]  Jeffrey L. Young,et al.  Electromagnetic wave propagation on a thin wire above earth , 2000 .

[4]  N. Theethayi,et al.  A Method for Interfacing Lumped-Circuit Models and Transmission-Line System Models With Application to Railways , 2009, IEEE Transactions on Electromagnetic Compatibility.

[5]  Marcello D'Amore,et al.  Simulation models of a dissipative transmission line above a lossy ground for a wide-frequency range. I. Single conductor configuration , 1996 .

[6]  Kai Li,et al.  Electromagnetic Fields in Stratified Media , 2009 .

[7]  James R. Wait Theory of Wave Propagation Along a Thin Wire Parallel to An Interface , 1972 .

[8]  J. R. Carson Wave propagation in overhead wires with ground return , 1926 .

[9]  David C. Chang,et al.  Modal theory of long horizontal wire structures above the earth: 1, Excitation , 1978 .

[10]  Clayton R. Paul,et al.  Analysis of Multiconductor Transmission Lines , 1994 .

[11]  Kai Li,et al.  Electromagnetic Field of a Horizontal Infinitely Long Wire Over the Dielectric-Coated Earth , 2012, IEEE Transactions on Antennas and Propagation.

[12]  H. J. Hagger,et al.  Electromagnetic Waves in Stratified Media , 1996 .

[13]  David C. Chang,et al.  Modal theory of long horizontal wire structures above the earth: 2, Properties of discrete modes , 1978 .