Features of current distribution in the traction rail network for heavy-haul traffic

2021 ◽  
pp. 52-58
Author(s):  
Maxim Viktorovich Basharkin ◽  
◽  
Alevtina Gennadyevna Isaycheva ◽  
Keyword(s):  
Current Distribution ◽  
Current Flow ◽  
Dynamic Loads ◽  
Automated Systems ◽  
Heavy Weight ◽  
Rail Network ◽  
Traction Current ◽  
Heavy Haul ◽  
Resistance Value

The paper investigates the limits of change in resistance value of traction rail network elements due to dynamic loads arising during the movement of trains with increased weight and length. An augmented electric diagram of rail joint with a duplicating junction coupler taken into account has been presented. The ways of traction current flow during simultaneous passing of heavy-weight trains along the adjacent track connected by intertrack junctions have been determined. Conclusions have been made about the necessity of constant monitoring of traction rail network elements condition, which can be ensured only by implementing special automated systems.

scholarly journals Simulation of the process of current distribution in a traction rail network

2021 ◽  
Vol 2094 (5) ◽  
pp. 052058
Author(s):  
A G Isaicheva ◽  
M V Basharkin ◽  
A L Zolkin ◽  
V N Malikov ◽  
V Saradzheva
Keyword(s):  
Current Distribution ◽  
Heavy Traffic ◽  
Dynamic Loads ◽  
Rolling Stock ◽  
Rail Network ◽  
Traffic Conditions ◽  
Electric Rolling Stock ◽  
Traction Current ◽  
Distribution Process ◽  
Heavy Traffic Conditions

Abstract The article synthesizes a simulation model of a section of a traction rail network, analyzes the norms of permissible asymmetry current, at which a choke-transformer is able to function with a set quality. The simulation of the current distribution process that occurs in the traction rail network during the movement of trains of increased weight and length has been carried out. The graphs of the dependence of the asymmetry current on the traction current consumed by the electric rolling stock have been obtained, and the simulation of the dynamics of changes in the traction current in each of the rail lines has been carried out when the train was moving along a section of the traction rail network. Conclusions about the need to monitor the state of traction rail network elements, the service life of which in heavy traffic conditions is significantly reduced both due to dynamic loads and due to overheating due to the passage of increased traction currents have been made.

scholarly journals Resistor Geometry Comparison With Respect to Current Noise and Trim Sensitivity

1977 ◽  
Vol 4 (2) ◽  
pp. 63-68 ◽  
Author(s):  
W. Ulbrich
Keyword(s):  
Finite Difference ◽  
Current Distribution ◽  
Current Noise ◽  
Total Resistance ◽  
Sheet Resistivity ◽  
Design Rules ◽  
Optimal Geometry ◽  
Practical Design ◽  
Finite Difference Solution ◽  
Resistance Value

The paper deals with laser trimming of film resistors. The finite-difference solution of the electric field calculated by a digital computer gives the total resistance and the inhomogeneous current distribution within the resistor area. The current noise voltage was found to be proportional to the sum of reciprocal subareas wherein the current density is approximately constant. Resistor trimming is modelled by finite increments of cut length to obtain the resistance trim rate and the trim sensitivity.Known and new resistor geometries and cut configurations are compared (based on the same resistor area and the same initial tolerance of ± 20%) to find the optimal geometry depending on the ratio of the nominal resistance value to the sheet resistivity. Diagrams are given leading to practical design rules not only for resistance trimming but also for deterministic and functional tuning.

scholarly journals Assessing the Damaging Effects of Railway Dynamic Wheel Loads on Railway Foundations

2017 ◽  
Vol 2607 (1) ◽  
pp. 62-73 ◽  
Author(s):  
Michael P. N. Burrow ◽  
Jin Shi ◽  
Mohamed Wehbi ◽  
Gurmel S. Ghataora
Keyword(s):  
Good Condition ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Field Investigation ◽  
Dynamic Loads ◽  
Foundation Soil ◽  
Railway Line ◽  
Track Condition ◽  
Heavy Haul ◽  
Track Quality

Dynamic train wheel loads, which can be significantly greater than static loads, occur because of a variety of factors and unless they are properly considered in track structural design, significant unplanned maintenance and premature track failure may result. This is particularly so for traditional ballasted railways built on soft foundations, because although ballast lends itself to maintenance, it is often problematic and costly to repair damaged foundations. A novel rigorous analytical–numerical approach is described to predict and characterize, for the first time, the damage to which railway foundations can be subjected as a result of dynamic loads. The approach marries a sophisticated three-dimensional dynamic model of the train–track system incorporating vertical track quality, foundation soil distress models, statistical analysis methods, and results of field investigation. The resulting analyses demonstrate that the magnitudes and distributions of dynamic loads are a function of train speed and track quality, and that specific locations experience significantly higher amounts of damage, which can lead to a variety of track faults. The approach is illustrated via a study of a heavy haul railway line in China where the wheel loads and tonnage carried are set to increase significantly. Findings from the study suggest that the thickness of the ballasted layer would need to increase by over 20% to prevent premature foundation failure provided that the track is maintained in good condition, and by significantly more should the track condition be allowed to deteriorate.

scholarly journals Study on Structural Service Performance of Heavy-Haul Railway Tunnel with Voided Base

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Zhiqiang Zhang ◽  
Bowen Zeng ◽  
Chaolong Dai ◽  
Wanping He
Keyword(s):  
Fatigue Life ◽  
Time History ◽  
Vertical Displacement ◽  
Surrounding Rock ◽  
Dynamic Loads ◽  
Vehicle Body ◽  
Monitoring Point ◽  
Heavy Haul ◽  
Heavy Haul Railway

The structural design of heavy-haul railway tunnels still follows the design method of ordinary railway tunnels. Most of them do not take into account the influence of large axle load of 30 t or more, let alone such problems as void of surrounding rock under long-term dynamic loads. In order to analyze the dynamic response of heavy-haul railway tunnels under long-term reciprocating cyclic dynamic loads, considering the factors such as axle load of vehicle body, unsprung mass, and track irregularity, the vibration load time-history curve of heavy-haul railway trains is determined, the three-dimensional dynamics coupling model of dynamic load-tunnel-surrounding rock is established, and the fatigue life of the structure under different void conditions is analyzed based on the S-N curve of concrete. According to the study, the loading, unloading, and vibration caused by train passing will lead to fluctuations in the vertical displacement response of the monitoring point. The peaks and valleys of the response time-history curve correspond to the effect of the train wheels rolling through. When the void is 6 m wide and 10 cm thick, the vertical displacement of the inverted arch is increased by about 9 times, the peak velocity of the inverted arch is increased by about 3.8 times, and the maximum principal stress is increased by about 47.3%, compared with the condition without void. With the same void thickness, the vertical displacement and velocity curves of the inverted arch vary significantly with the increase of the void width. The width of the base void has a significant effect on the fatigue life of the structure of heavy-haul railway tunnels. Based on the operation requirement of 100-year service life, the ultimate void width is 2 m.

scholarly journals Elektromagnetiese modelle vir elektriese spoorbaanstelsels

1997 ◽  
Vol 16 (2) ◽  
pp. 86-95
Author(s):  
B. M. Steyn ◽  
J. D. Van Wyk
Keyword(s):  
Performance Analysis ◽  
Transmission Line ◽  
Current Distribution ◽  
Electromagnetic Interference ◽  
Railway Track ◽  
Traction Current ◽  
Different Types ◽  
Track Circuits ◽  
Track Circuit ◽  
Electromagnetic Models

The use of electromagnetic models is very expedient when railway track circuits are designed or when their operation is being studied. These electromagnetic models include models for performance analysis of the different types of track circuits as well as models used to study the effect of electromagnetic interference. Before these models can produce useful results they all require accurate input parameters. These parameters include the transmission line parameters of the track and the traction current distribution along the length of the track. Models that have been developed for these parameters are presented in this paper, together with an overview of the available track circuit models.

Models and Algorithms of Locomotive Layout Optimization in Regional Heavy Haul Rail Network

2013 ◽  
Vol 13 (9) ◽  
pp. 1544-1550
Author(s):  
Junhua Chen ◽  
Qi Liu ◽  
Jian Yu ◽  
Yajing Zheng
Keyword(s):  
Layout Optimization ◽  
Rail Network ◽  
Heavy Haul

scholarly journals Imaging current distribution in a topological insulator Bi2Se3 in the presence of competing surface and bulk contributions to conductivity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amit Jash ◽  
Ankit Kumar ◽  
Sayantan Ghosh ◽  
A. Bharathi ◽  
S. S. Banerjee
Keyword(s):  
Thin Films ◽  
Topological Insulator ◽  
Current Distribution ◽  
Current Density ◽  
Current Flow ◽  
Bulk Conductivity ◽  
Imaging Studies ◽  
Temperature Dependent ◽  
Edge Current ◽  
Sheet Current

AbstractTwo-dimensional (2D) topological surface states in a three-dimensional topological insulator (TI) should produce uniform 2D surface current distribution. However, our transport current imaging studies on Bi2Se3 thin film reveal non-uniform current sheet flow at 15 K with strong edge current flow. This is consistent with other imaging studies on thin films of Bi2Se3. In contrast to strong edge current flow in thin films, in single crystal of Bi2Se3 at 15 K our current imaging studies show the presence of 3.6 nm thick uniform 2D sheet current flow. Above 70 K, this uniform 2D sheet current sheet begins to disintegrate into a spatially non-uniform flow. The flow becomes patchy with regions having high and low current density. The area fraction of the patches with high current density rapidly decreases at temperatures above 70 K, with a temperature dependence of the form $$1/\left| {T - 70} \right|^{0.35}$$ 1 / T - 70 0.35 . The temperature scale of 70 K coincides with the onset of bulk conductivity in the crystal due to electron doping by selenium vacancy clusters in Bi2Se3. Thus our results show a temperature dependent competition between surface and bulk conductivity produces a temperature dependent variation in uniformity of current flow in the topological insulator.

scholarly journals CURRENT DISTRIBUTION DEPENDENCE ON ELECTRIC FIELD IN HELICALLY COILED CARBON NANOTUBES

2017 ◽  
Vol 8 (2) ◽  
Author(s):  
Zoran P. Popović ◽  
Tatjana Vuković ◽  
Božidar Nikolić ◽  
Milan Damnjanović ◽  
Ivanka Milošević
Keyword(s):  
Carbon Nanotubes ◽  
Electric Field ◽  
Current Distribution ◽  
Current Flow ◽  
Distribution Functions ◽  
Intensity Change ◽  
Single Wall Carbon Nanotubes ◽  
Boltzmann Transport ◽  
Nonequilibrium Electron ◽  
Localized Magnetic Field

Experimentally is confirmed that helically coiled carbon nanotube (HCCNT) could be used as a small solenoid for generating spatially localized magnetic field. Current distribution during diffusive electronic transport likewise the inductivity of this quantum conductor depends on electric field. Despite slightly lower electron mobility in HCCNTs than that of the straight single wall carbon nanotubes, the coiled nanotubes are attractive for application as nonlinear nano-solenoids. Nonequilibrium electron distribution functions obtained by solving Boltzmann transport equation are used to predict average helical radius of current flow as a function of electric field intensity. Change of spatial distribution of electronic flow with applied electric field is considered and nonlinear inductivity of HCCNT is predicted.

scholarly journals Imaging current distribution in a topological insulator Bi2Se3 in the presence of competing surface and bulk contributions to conductivity

2021 ◽  
Author(s):  
Amit Jash ◽  
Ankit Kumar ◽  
Sayantan Ghosh ◽  
A. Bharathi ◽  
S. Banerjee
Keyword(s):  
Thin Films ◽  
Topological Insulator ◽  
Current Distribution ◽  
Current Density ◽  
Current Flow ◽  
Bulk Conductivity ◽  
Imaging Studies ◽  
Temperature Dependent ◽  
Edge Current ◽  
Sheet Current

Abstract Two-dimensional (2D) topological surface states in a three-dimensional topological insulator (TI) should produce uniform 2D surface current distribution. However, our transport current imaging studies on Bi2Se3 thin film reveal non-uniform current sheet flow at 15 K with strong edge current flow. This is consistent with other imaging studies on thin films of Bi2Se3. In contrast to strong edge current flow in thin films, in single crystal of Bi2Se3 at 15 K our current imaging studies show the presence of 3.6 nm thick uniform 2D sheet current flow. Above 70 K, this uniform 2D sheet current sheet begins to disintegrate into a spatially non-uniform flow. The flow becomes patchy with regions having high and low current density. The area fraction of the patches with high current density rapidly decreases at temperatures above 70 K, with a temperature dependence of the form 1/|T-70| 0.35. The temperature scale of 70 K coincides with the onset of bulk conductivity in the crystal due to electron doping by selenium vacancy clusters in Bi2Se3. Thus our results show a temperature dependent competition between surface and bulk conductivity produces a temperature dependent variation in uniformity of current flow in the topological insulator.

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