Hamidov M., Cafarli S.
OPTIMIZATION OF ELECTRICAL EQUIPMENT OF ELECTRIFIED RAILWAYS *
Аннотация:
the traction power supply system and the energy of train movement operating on alternating current are justified. Measures are shown for the efficient use of electrical energy in real operating conditions of electric traction rolling stock during the start, acceleration and deceleration of trains.
Ключевые слова:
research, result, railway, electric locomotive, operation, alternating current, power supply, electric energy
In the process of electrification of railways, complex power supply is carried out not only for the entire railway infrastructure, but also for industrial enterprises and non-traction consumers located near the railway. Therefore, the railway traction power supply system generally includes the following elements: transmission lines of the electrified railway, traction substations, contact network and transmission lines for non-traction consumers.Currently, the main "suppliers" of electric power for electric locomotives are thermal, hydroelectric and nuclear power plants that produce three-phase current. The electricity produced by the generators of power plants is transferred through buses, high-voltage switches, fuses and contactors.It is transmitted to transformers. These transformers step up the voltage to 500 kV and higher. The high-voltage power is then fed through transmission lines and transmitted as alternating current or converted to direct current by static rectifiers and fed into the transmission line.Transformers installed at traction substations reduce the voltage of the high-voltage transmission line to approximately 27.5 kV, which is approximately 10% higher than the nominal voltage provided in the contact network. This voltage is first transmitted to the tires and then to the contact wires and rails through high-voltage switches.In order to distribute the load of the phases evenly, phase A is usually supplied to the contact network of one crossing area (area a), phase B to the contact network of the other crossing area (area b), and phase C is supplied to the rails. Therefore, when an electric locomotive is moving in one crossing area, it receives energy from phases A and C, and when moving in the other area, it receives energy from phases B and C.In the case of two-way feeding, if the “a” transition area is powered by phases A and C, the “b” transition area is powered by phases B and C. In this case, the station tracks are fed from any phase pair through isolators. When the train is moving and the pantograph (current collector) sliding head is switched from phases A and C to phases B and C (or vice versa), the contact networks fed from different phases must be electrically isolated from each other, since there is full voltage between these phases. Therefore, the division (sectioning) of the contact network by air gaps (6) alone is not sufficient for electrical insulation. Therefore, a neutral section between the station tracks and the “b” transition area(7) and two air gaps (6) are installed. Such a contact network sectioning system eliminates short circuits between phases through the sliding head of the pantograph.Figure 1. Power supply of an alternating current traction power supply network.In such a system, the electric traction composition operating on single-phase direct current may have direct current traction electric motors (for example, the 3VL80S series electric locomotive), asynchronous traction motors, or valve motors whose operating principle is similar to a synchronous motor.Thus, traction electric rolling stock, especially electric locomotives, are driven by traction motors that receive energy from power plants via transmission lines, traction substations, and contact wires and convert this energy into mechanical work. This mechanical work is transmitted from the motor shaft to the wheel pairs and is used to move the train.In general, part of the locomotives mechanical work is spent on overcoming the main and additional resistance forces against the trains movement, and the other part is spent on creating a reserve of kinetic and potential energy during the trains movement.In addition, increasing the speed of the train also causes an increase in the main motion resistance forces, which ultimately leads to more mechanical work being done by the locomotive.The kinetic and potential energy stored in the descent areas can be fully utilized for the movement of the train without the need for additional energy from the contact network. As the train moves downhill, the increase in its speed causes some of the potential energy to be converted into kinetic energy. As a result of the mechanical or rheostat electric braking modes applied to maintain the train at a constant speed or to reduce its speed on horizontal areas, some of the stored kinetic and potential energy is lost through the brakes.To substantiate the energy processes during the movement of a train, let us consider one of the possible options for movement on a horizontal railway track of length s, powered by alternating current (Fig. 2). It is shown here:– abpart – traction mode carried out with the consumption of electric energy,– b.c.part – idle mode (wheel drive),– cdPart 1 – mechanical braking mode.Figure 2. Curve of the trains speed along the horizontal railway area.RESULT.Thus, recommendations on the correct and efficient management of drivers during the operation of traction electric rolling stock can undoubtedly ensure savings in the amount of electric energy spent on traction of trains. Therefore, in each locomotive depot, based on the experience of the best drivers, the energetics of train movement and mathematical methods of optimal control, train control mode tables (mode cards) are developed, reflecting the rational operating modes of the power systems of the electric rolling stock.It is recommended that the results of the conducted research be used when assessing the traction and energy efficiency of electric traction locomotives operating on alternating current, in the conditions of organizing real freight and passenger transportation on electrified sections of the Uzbek railways.
Номер журнала Вестник науки №5 (86) том 4
Ссылка для цитирования:
Hamidov M., Cafarli S. OPTIMIZATION OF ELECTRICAL EQUIPMENT OF ELECTRIFIED RAILWAYS // Вестник науки №5 (86) том 4. С. 1521 - 1525. 2025 г. ISSN 2712-8849 // Электронный ресурс: https://www.вестник-науки.рф/article/23460 (дата обращения: 17.07.2025 г.)
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