Vol 88, No 9 (2017)

One method to increase the quality of control of automatic control systems of the freight-train speed is to use a reference train model in an automatic control system to consider the dynamic processes occurring in the train. Based on this information, the system operates so as to fulfill the requirements for control quality of the speed according to a given system of criteria. However, the use of the complex reference model reduces the parameters of the automatic control-system response speed. It is possible to simplify the model to increase the response speed, thereby decreasing the order of the system of the differential equations describing the train as the object of control. Surveys that have been carried out made it possible to find the admissible degree of simplification of the model that does not cause a significant decrease in the accuracy of calculations.

Ways to develop and improve traction power-supply systems and adapt them for high-speed highways are considered. One way to improve a traction power-supply system and make it more efficient is to increase the nominal voltage in the dc traction network up to 24 kV. This allows one to increase the throughput and carrying capacities of railways, increase the distance between substations, reduce the cross section of traction-network wires, and significantly reduce power losses in power-supply facilities. All this, alongside the absence of unbalanced supply voltage and inductive losses, as well as a significantly lower electromagnetic action on the infrastructure under dc conditions, results in a greater efficiency than in the case of any alternating- current traction power systems of alternating current. A mathematical model of dynamic electromagnetic processes in electrical circuits with semiconductor converters is fleshed out. Analysis and synthesis of electromagnetic processes and the main characteristics of multipulse converters, as well as a comprehensive technical and economic comparison, shows that 24-pulse rectifying circuits with a serial connection of threephase bridge are most efficient for these systems. These rectifiers provide an improvement in the quality of electrical energy not only for the primary power-supply system, but also for the traction network. They allow one to use simpler and more economical active-passive smoothing filters that provide the electromagnetic compatibility (EMC) of a new traction dc power system with the communication and railway automation facilities. In addition, the use of 24-pulse rectifiers can allow one to significantly reduce the consumption of reactive energy, reduce power losses in a traction network, and increase the efficiency of traction substations.

The assessment of the possibility to use the potential of wind energy for power supply of the traction railway network in the context of the area of Karatau in the southern region of the Republic of Kazakhstan, the main wind-energy characteristics of the region are determined. An comparison of the program is presented with the results of statistical processing of the data sets on the long-term monitoring of the wind indicators of the investigated region with wind-speed determination during a month, mathematical expectations, law of the probability density of wind-speed distribution for a month, diagrams of wind distribution according to days within a month, instantaneous values (gusts) of wind speed for 24 h, and average wind speed by time of day for a month. A diagram of a traction power-supply system with distributed energy generation is given based on wind-power plants, their equivalent circuit and design including the wind generators, rectifying and inverting converter units, as well as the electric-energy accumulator with the direct current converter. Theoretical dependences are obtained to determined additional electric-energy losses in the traction network during redistribution of energy in the traction power-supply system from the main traction substations to energy-storage units at the “wind” traction substations during periods of an unfavorable wind situation in the region. The operation regimes of the electric-power facilities incorporated into the traction powersupply system and “wind” traction substations are described taking into account the pure traction mode from the wind electricity generator, power supply of trains from energy-storage units under conditions of the insufficient wind force, and energy-recovery regimes during braking of the trains, as well as with qualitative determination of their operating parameters. The main electrical characteristics of the equipment of the “wind” traction substations are determined.

This article describes the case of one of possible method of controlling a linear asynchronous motor (LAM) with a controlled normal component of the force of interaction between an inductor and a reactive bus. It is shown that the normal force in a unilateral linear asynchronous motor can affect significantly the operation of devices and systems on which a motor is installed. This normal force can attract an inductor to a reactive bus or repel it from a reactive bus. For the model of a motor, which is represented by four zones, namely, an inductor, an air gap, a conductive bus, and a steel core of a reactive bus, the analytical expressions for the calculation of the components of a magnetic field in an air gap were obtained. The effect of the longitudinal and transverse edge effects in the considered plane model of a motor is not considered. The expressions for the determination of the specific tangential and normal forces per area unit were found. It is shown that, under a change in the slide from negative to positive values, the tangential force changes similarly to the electromagnetic torque of a conventional asynchronous motor with a rotating rotor. Under a change in the slide, the normal force can attract an inductor to a reactive bus or repel it from a reactive bus. The force of attraction reaches the highest values under a zero slide. The slide under which the normal force is equal to zero is determined only by the pole pitch and the conductivity of material of a reactive bus and provides the operation of a motor at the highest power factor. It is proposed to use the measured normal force value as a parameter for the construction of a traction linear asynchronous motor-control system.

Determination of the need for and timeliness of repairs of machines (or for replacing their components) are primary concerns of applied reliability theory. A decision is made as to whether repairs need to be carried out or not on the basis of on examination of the efficiency of the machine, which is determined by comparison of a number of economic, technical, and ecological indices. It is clear that this is a multicriterion problem. One of the most important criteria (but not the sole one) is mean operating time to failure. In general, assuming that there is a representative failure database, this is done via procedures of reliability theory. The paper discusses the need of the solution of reliability problems for a class of objects subjected to a nonstationary failure flow at a periodic piecewise constant rate. Examples of such objects are given. The reliability function and mean operating time to failure are determined analytically. A model of failure is given using states of an object that are each determined by a specific failure rate. The object states are repeated in a given period. In addition, the special case of two states that correspond to the seasonally changing of failure rate is considered. An analysis of the effects of various failure rates on the mean operating time to failure is carried out.

An assessment of the overall performance of 3ES5K alternating-current electric locomotives with a collector drive in the regimes of traction and recuperative braking using the concrete example of a staged route between the Khabarovsk-2 and Bikin stations of the Far East Railroad is given in this article. Real traction and brake characteristics of a 3ES5H electric locomotive in the case of a cargo train of large weight and length are shown. Analysis is carried out of all the characteristics of a 3ES5H electric locomotive, and they are compared with the movement of a 2ES5 electric locomotive with an asynchronous drive. It is determined why 3ES5K electric locomotives are more power efficient than 2ES5 ones.