Purpose: To obtain analytical dependencies for the optimal allocation of resources of various type recovery trains with the purpose to restore in the shortest possible timeframes of railway facilities destroyed as a result of regional emergences. Methods: A heuristic method of optimal resource allocation of various type recovery trains through railway facilities, destroyed as a result of a regional emergences, is applied. Proof of the optimality of the proposed heuristic method is given. Results: Within the proposed method frames, new analytical dependencies are derived for the distribution of resources of recovery trains of various types through railway facilities destroyed as a result of regional emergences. Mathematical formulation, based on the formulation of non-linear model of operations research theory, as well as solution algorithm of the task for the distribution of resources of recovery trains of various types through railway facilities destroyed as a result of emergences of a regional scale are given. Practical significance: On the basis of the considered dependencies, it is possible to increase the efficiency of calculation operativeness allowing to embody reasonable allocation of recovery trains of various types for the restoration of railway facilities destroyed as a result of regional emergences. The results of the study can be applied to the creation of informational-predicted systems that promptly implement the proposed analytical dependencies for more efficient restoration of railway facilities destroyed as a result of emergences of a regional importance.
While developing a new modern device for diagnostics and monitoring of the grounding system in real time, the existing modern devices for diagnostics and monitoring of the railway traction network have been analyzed and specific features of high-speed rail traffic development have been studied. The paper presents the existing devices and methods for diagnostics and monitoring of the power supply elements of railway traction. The basic principles of operation of the devices used are given and their advantages and disadvantages are analyzed. The presented analysis makes it possible to estimate the new tendencies in diagnostics and monitoring system development and to summarize further prospects of their implementation and improvement.
The research is aimed at studying the catenary wires power losses change by transverse capacitive compensation with considering the movement of trains on the intersubstation zone. Calculations instantaneous and average catenary wires power losses while passing through the intersubstation zone one train and two successive trains are presented in this article. Losses are determined for two cases: when installed compensating device and in its absence. The values of the differences of these losses are founded. The computer simulation in MATLAB-Simulink software was implemented. According to the results of calculations graphs were built, illustrating the change of catenary wires power losses while moving trains on the intersubstation zone when installed compensating device and without it, as well as the differences between the said losses. Average values of catenary wires power losses were determined by integrating these functions and their comparison is carried out. Calculations have shown that by selecting compensating device power by the average reactive power consumed by a train, its intersubstation zone passage with constant current causes the same average catenary wires power losses as in the absence of the compensating device. Increasing the number of trains, simultaneously located on the intersubstation zone at the same compensating device power, entails a reduction of catenary wires power losses with respect to a similar situation without the compensating device, but at the same time reactive power is compensated only partially.
The manufacture of current transformers is associated with many design constraints, which include the restricted dimensions of its installation places, requirements for the accuracy class, as well as the limitation on the safety factor or the minimum factor of the accuracy limit factor. In a design sense of current transformers, these requirements are contradictory, which resulting in a flexible approach to the manufacture of current transformers. The use of combined magnetic cores can be referred to one of these areas, in other words magnetic cores consisting of materials with different magnetic properties, which allows to obtain unique magnetic properties that are inaccessible when using magnetic cores of the same type (material), thus providing a rational model of production. The article presents a feature of calculating of current transformer with combined magnetic cores.
The aim of the study is to review the sources covering the problems of accumulating electricity on the railways and to find new solutions to reduce the use of electricity in traction power supply system. The article analyses some existing types of electric energy storage devices (capacitive, inertial, superconducting inductive, electrochemical, fuel cells and pumped storage power plants), their common installation locations, advantages, and disadvantages. The possibility of using them in railway traction power supply systems, in particular in mobile traction substations, is also assessed. In addition, the article lists the parameters on the basis of which the optimum type of storage device can be selected for the given conditions. The study concludes that the use of some types of energy storage devices in mobile traction substations is acceptable when regenerative braking can be used at the site, and this method of energy saving can be recommended in the engineering of new or reconstruction of existing traction substations. It has been found that capacitive and inertial (flywheel) electrical energy storage units are the most suitable in terms of parameters for installation of traction power supply systems.
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