Abstract
Purpose. To conduct the study of the potentials and currents propagation along the rails to evaluate the potential difference and the current asymmetry in the rails that may have an impact on the work of railway automatics and supervisory systems. Methodology. To compass the purpose, the author applies methods of analysis and synthesis of track circuit electrical engineering calculations, mathematical modeling and methods of homogeneous and heterogeneous ladder circuits. Findings. TheconductedtheoreticalstudiesindicatethatinthemountainoussectionsofDCtractionrailwaysthereareveryhigh-levelcurrents,wherebyevenatnominalasymmetryratio theasymmetrycurrentwill beunacceptablyhigh.The re-equipment of running line with the automatic blocking system with tonal rail circuits resulted in reduction of the number of impedance bonds, the equalizing functions of which required further advanced research, that allowed obtaining the potential railwise propagation curves when installing the impedance bonds every 6 and 5 km. The resulting potential difference was too high for railway automation systems, so the potential propagation study was conducted with impedance bonds placed every 3 and 3.5 km, which greatly improved the operation conditions of track circuits. Originality.The proposed method for calculating the propagation of potentials and currents in the rail network of DC traction line is characterized by the representation of the common ladder circuit of each rail as a series of T-shaped four-poles connected in cascade, taking into account the grounding of the contact-line supports on the nearer rail. It has allowed estimating the levels of asymmetry currents that branch into the equipment of track circuits and have a negative impact on their operation. Practicalvalue. The obtained results can be used in designing and re-equipping the running lines with new railway automatics and supervisory systems, as well as for evaluating the influence of high asymmetry currents on the railway automation systems operation.
Highlights
Traction current has a significant impact on the operation of automatic block systems (AB) [1]
The problem of railwise propagation of potentials caused by traction current becomes actual, the study of which will allow to estimate the difference between the derived potentials and the negative impact on the equipment of the track circuits (TC), in particular, the tonal ones (TTC)
As a result of the carried out researches it was established that traction currents reach 7000 A on this site and it is expedient to re-equip the section AB with 50 Hz frequency TC onto the ABTK system, which uses TTC without isolating joints [2], resulting in reduced number of impedance bonds (IB), as in the case of TTC, they are installed only for the potential alignment in the rails, while the IBs pass less current
Summary
Traction current has a significant impact on the operation of automatic block systems (AB) [1]. There are rail sections where it reaches very high levels, resulting in melting of track choke cables. Such are the mountain sections of railways with electric drive of direct current. The purpose of the work is to study the propagation of potentials along the rails in order to evaluate the impact of traction current on TTC operation. This will enable us to take a number of necessary technical measures to combat asymmetry, as well as to investigate their effectiveness in advance
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