This article describes the issues related to the analysis of the reliability-exploitation of power supply systems in transport telematics devices (PSSs in TTDs). This paper characterizes solutions, which are applied in supply systems, and describes a PSS in a TTD from a main source and a standby one. This enables determining the dependencies denoting the probabilities of the system staying in full ability state, safety threat state, and safety unreliability state. A quality analysis of the PSS in TTD was conducted, and the indicator value of the supply continuity quality was evaluated. This indicator allows the demonstration of continuity quality of power supply (CQoPS) dependency on many quality dimensions, not just reliability. An example demonstrates the calculation of CQoPS factor for both the main and the standby power supply, employing three observations, each influencing the quality. The presented considerations in the field of quality and reliability-exploitation modeling of a PSS can be applied as well in other public utility facilities (including those classified as critical infrastructure). The character of functions performed by critical infrastructure facilities demands an operating continuity of these systems at an appropriate level. The co-first authors of the article once again address the issue of determining CQoPS factor, this time on the basis of modeling using mathematical evidence. TTD is an example in this article, because the presented methods can be used in any kind of system, especially in the power source of critical systems.

Quality and Reliability-Exploitation Modeling of Power Supply Systems

The analysis of operating conditions of induction traction motors as part of traction electric drives of electric locomotives reported here has revealed that they are powered by autonomous voltage inverters with asymmetric non-sinusoidal voltage. It was established that the induction motor operation may be accompanied by defects caused by the asymmetrical modes of the motor stator. A model of the induction motor has been proposed that takes into consideration changes in the values of mutual inductance of phases and complete inductance of the magnetization circuit due to changes in the geometric dimensions of the winding caused by a certain defect. An algorithm that considers the saturation of the magnetic circuit of the electric motor has been proposed.
This approach to modeling an induction motor is important because if one of the stator's windings is damaged, its geometry changes. This leads to a change in the mutual inductance of phases and the complete inductance of the magnetization circuit. Existing approaches to modeling an induction motor do not make it possible to fully take into consideration these changes.
The result of modeling is the determined starting characteristics for an intact and damaged engine. The comparison of modeling results for an intact engine with specifications has shown that the error in determining the controlled parameters did not exceed 5 %. The modeling results for the damaged engine demonstrated that the nature of change in the controlled parameters did not contradict the results reported by other authors. The discrepancy in determining the degree of change in the controlled parameters did not exceed 10 %. That indicates a high reliability of the modeling results.
The proposed model of an induction electric motor could be used to investigate electromagnetic processes occurring in an electric motor during its operation as part of the traction drive of electric locomotives

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Improving a model of the induction traction motor operation involving non-symmetric stator windings

One of the assumptions made during the modernization process of diesel shunting locomotives is the replacement of a diesel traction motor with a DC generator with an electric asynchronous traction motor. The article aimed to develop a method of selecting energy-efficient parameters of an asynchronous electric traction motor for diesel shunting locomotives, which will ensure that its operating energy efficiency will be as high as possible. The method was verified on the example of a locomotive series ChME3 (ЧMЭ3, ČME3, ČKD S200). It has been found that using a traction asynchronous electric drive on a ChME3 locomotive, its efficiency increases in comparison with DC electric motors by 3–5% under the long-term operation modes and by 7–10% during locomotive operation with traction at the adhesion limit. Using a new traction gearbox with a higher gear ratio expands the speed range in which the asynchronous traction drive operates with a high-efficiency factor. It is effective to use a traction asynchronous electric drive to modernize ChME3 diesel locomotives in case of their use under the modes requiring the implementation of maximum traction forces at low speeds. A further increase in the efficiency of the traction asynchronous electric drive is possible based on the optimal design of the wheel-motor unit and the asynchronous traction electric drive.

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Method of Selecting Energy-Efficient Parameters of an Electric Asynchronous Traction Motor for Diesel Shunting Locomotives—Case Study on the Example of a Locomotive Series ChME3 (ЧMЭ3, ČME3, ČKD S200)

Shunting work on sorting wagons is carried out on steeper profiles and requires the operation of shunting diesel locomotives of a higher power. Many sorting operations use double traction of shunting locomotives in conditions of the highly outdated fleet of shunting diesel locomotives. However, the technology of operating two shunting locomotives requires substantiation of its scope of application. In this article, using the example of station “X”, the technology of disbanding trains from the sorting hump is investigated in two ways: the first is the existing technology (work on disbanding trains is carried out using two shunting locomotives of the TEM-2 series), shunting locomotive of TEM-7 series. It has been determined that in the existing technology, the required processing capacity of the hill approaches its maximum value. When using the TEM-7 diesel locomotive, the maximum processing capacity of the hill increases by 27%. The sphere of efficiency of the TEM-7 series locomotive instead of two TEM-2 was substantiated by the method of technical and economic calculations.

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Method for substantiating the spheres of application of shunting locomotives at sorting stations

The paper deals with development of the mathematical model of the two-mass electric drive of a direct current of the electric locomotive with the observer of a full order. The model provides an opportunity to study the change in the ratio of the moments of inertia of the two masses of the electric drive in order to reduce speed fluctuations and inconsistencies in the speeds of these masses. The observer estimates the speed on the basis of information about the supply voltage and motor current. Instead of directly measuring the speed, an observer is used, who uses the measured armature current and supply voltage to change the task to speed. As a comparison, the classical model of subordinate coordinate control for a two-mass electric drive is considered. The disadvantages of the latter are the complexity of calculating the parameters of the links during debugging. Identification and description of the load moment is carried out by a system of differential equations. Reproduction of the vector of coordinates of the system and the vector of perturbations (load moment) is carried out by the observer with an error in the steady state. To compensate for it, the load torque signal in the static is fed to the input of the speed circuit through the debugging link. The results of research on the mathematical model, with its appropriate adjustment under the conditions of a particular electric drive, can significantly reduce the impact loads on the electric drive by accurately matching the speeds of two masses and from a practical point of view provide information on calculations of the kinematic circuit and selection of optimal gear ratio.

Model of Two-Mass Electric Drive of DC Electric Locomotive with the Full Order Observer

Shunting is an integral part of the partial process. In 1520 mm gauge countries, shunting operations are performed by outdated locomotives, which are being replaced by modern models; the technical parameters best match the conditions of the shunting work performed.\nThe article analyzes recommendations for the selection of parameters of shunting locomotives and the actual indicators of their work. On the basis of this analysis, a requirement was made on the necessity of compulsory consideration of the operating conditions of the locomotive when determining its technical characteristics.\nAs the main technical parameters of shunting locomotives, the tractive power and starting tractive force are taken and their influence on the duration of an elementary shunting movement of the \"acceleration-deceleration\" type is investigated. This approach advises the regulatory documentation for the organization of shunting work.\nTha developed mathematical model allows to carry out research on the influence of tractive power and starting tractive force on the time of acceleration and deceleration. Calculations of the time of the train's acceleration are carried out with varying their mass and the slope of the track at different values of the tractive power starting tractive force. The calculations were carried out for the mass of compositions 1000...5000 Mg for the profile slopes equal to 0 and 1.5 ‰. The speed of the finish of acceleration was taken equal to 15 and 25 km/h. The thrust starting tractive force varied in the range of 150...300 kN, the tractive power - 200 ... 1100 kW.\nAccording to the results of calculations, it was found that the reduction in the duration of the elementary shunting movement is more significantly affected by the power of the locomotive than by the starting traction force. The “saturation” effect was noted, in which a significant increase in power or traction force during starting does not cause a significant reduction in the acceleration time. In this regard, for shunting locomotives with AC traction drive, it is recommended to take a pulling force of an equal continuous traction force.\n\n

Borys Lyubarskyi

Papers

Recommendations for the selection of parameters for shunting locomotives