Adaptation of electric rolling stock of the subway with asynchronous traction motors to a three-wire traction power supply system is considered. In the previously proposed three-wire topology, the running rails of both tracks, connected by cable jumpers through the midpoints of the choke transformers, operate as a zero wire, which ensures the flow of currents and reduces power losses. However, for electric trains following one of the paths, the voltage polarity on the current collector is reversed, which creates the risk of a short circuit through the reverse diodes of the IGB transistors and eliminates the possibility of regenerative braking. To remove these limitations, a modified circuit solution using a bridge converter based on IGB transistors is proposed, in which the protective diodes of the transistors are a protection against reverse polarity, and the transistors themselves perform the function of bidirectional transmission of electricity. The circuit provides constant voltage polarity at the output of the converter, regardless of the input polarity, automatic detection of traction and recuperation modes, as well as the generation of appropriate control signals for IGB transistors without the involvement of maintenance personnel. The operability of the proposed solution is confirmed by the results of simulation modeling in the MATLAB Simulink environment at time intervals covering the driving modes on both tracks and the regenerative braking mode. It is shown that the proposed modernization can be implemented on mass-produced rolling stock using IGB transistors manufactured in Russia.
When a rail fractures on sections with electric traction, the relative value of traction-current asymmetry in the rail line, as measured by the asymmetry coefficient, becomes maximal at the fracture location. The traction-current asymmetry increases in the rail line as one approaches the fracture site, and beyond the fracture it gradually decreases. The rate of increase or decrease of this traction-current asymmetry along the rail line depends on the electrical and magnetic parameters of the rail conductors. The transverse resistance of the rail conductors, their resistance to earth, has the strongest influence on this rate. The traction rail network can be represented as a complex electrical circuit, which makes it relatively straightforward to quantitatively assess the influence of a rail fracture on the flow of electric current in such a circuit. This approach made it possible to develop a calculation methodology to detect the occurrence and location of a rail fracture. The article presents some results from the application of this methodology.
This paper presents a comparative analysis of four metaheuristic algorithms for the placement of electric vehicle charging infrastructure. The analysis is based on the calculation of installation locations and the selection of charging station capacity on the M-11 Neva highway. A genetic algorithm, particle swarm method, differential evolution, and simulated annealing (selection) are considered. All methods solve the same problem on the same demand model, use the same computational resources, a single set of scenarios, and the same conditions. Five different operating scenarios were studied for these algorithms, differing in power grid operating conditions, highway traffic, etc., with each scenario analyzed under different initial conditions. The study combines the results of over 38 000 objective function calculations. It is shown that, according to a complex indicator that combines the quality of the objective function, project implementation cost, stability, and computation time, the particle swarm method proved to be the best, but it is also the most expensive and the slowest. The nonparametric Friedman’s test of integrated utility confirmed that the differences between the algorithms are statistically significant. A route mapping demonstrates that the identified advantage method achieves its benefits primarily by reducing infrastructure density and overall cost, rather than by maximizing the service level of charging stations.
A subsystem for automatic control of train speed is proposed as part of an interval-based traffic regulation system for high-speed trains, as a means of ensuring traffic safety. Two methods for controlling the acceleration of the trailing train are considered: one requires information about the speeds of the controlled trains, while the other, in addition to speed, requires information about the trains' positions. Analysis of simulation results showed that both methods provide control of the train’s traction and braking systems in such a way as to ensure the minimum separation interval between trains traveling in the same direction. Recommendations are given for selecting the train control law, and requirements for the control system hardware are formulated.
The digital transformation of rail transport necessitates the implementation of innovative solutions aimed at intelligentizing technological processes and increasing equipment productivity. The railway network vast geography creates significant challenges for infrastructure management. Electrified lines account for approximately 85
