Category: Transport control systems


Shamanov V. I.

The article is devoted to the issues of increasing the stability of the operation of track circuits under the influence of interference from alternating traction current. Track circuits are widely used on railways around the world to monitor the occupation by rolling stock and the integrity of rails on a railway section. In modern multilevel systems of interval regulation of train traffic using digital radio channels and satellite navigation, track circuits are also used. It was found that the appearance of asymmetry of the longitudinal and / or transverse resistances of the rails is only the root cause of the asymmetry of the traction current. The mutual inductance of the rails in the rail line increases the value of the asymmetry of the traction current by several times. The degree of this increase depends on the temperature of the rails and the value of the traction current in them. The mutual inductance of the rails of the rail line with the parallel rails of other track circuits can both increase and decrease the asymmetry of the traction current depending on the nature of the distribution of the traction current along the rails of the adjacent track circuits. The mutual inductance of rails with longitudinal power supply lines located on the supports of the contact network can noticeably affect the value of the asymmetry. The degree of distortion of the signal current sinusoidality is determined by the harmonics of the asymmetry current. The harmonic composition of interference from traction current can quickly change over time and depends on the number, series and operating modes of traction equipment of electric locomotives moving in the area between traction substations. It is shown that electric filters used in track circuits do not always provide the required interference filtering efficiency.

Key words:
track circuits, rail lines, mutual inductance, traction current, asymmetry, interference, harmonic composition, operation stability

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