Algorithm for implementing energy-efficient traction substations on the subway

The work is devoted to the modernization of traction substations on the subway. The paper deals with the problem of using energy-saving technologies in the subway. The practical value of the work results lies in solving an urgent problem aimed at reducing the level of power consumption in the metro system. The paper considers the possibility of modernizing traction substations by using multiphase solutions that improve the stabilization properties of the rectified voltage and reduce the loss of electricity by energy output to storage devices installed on the vehicle. Circuitry solutions have been developed for transformer-rectifier units (TRU) with 24-fold rectified voltage ripple, which make it possible to reduce active power losses in transformer equipment and valve structures and to increase the stabilizing properties of the rectified voltage.


Introduction
The strategic direction of priority development of many areas of industry and sectors of the economy, including the transport industry, in connection with the worldwide rise in energy prices, is the problem of reducing losses in the transformation, distribution and consumption of energy. The liberalization of the Russian energy market implies an increase in energy prices. The inevitable increase in the energy component of costs in energy-intensive industries at a rate of 6%-8% per year will require not only the introduction of energy-saving technologies in all industries, but also the development of fundamentally new solutions aimed at increasing the efficiency of energy conversion. It is possible to create competitive samples in the domestic and global markets only through the use of the latest technologies and developments in the element base, using modern materials for electric rolling stock (EPS) [1,2].
In recent years, one of these areas has been the development of new types of efficient sources of secondary energy and energy converters with qualitatively new properties that allow them to be effectively used in the transport industry of the country, reducing energy losses, increasing efficiency, increasing the service life of equipment and the reliability of the electric transport complex in the whole.
At the turn of the 20 th and 21 st centuries, in connection with significant progress in information technologies, it became possible to quickly and efficiently perform complex and laborious calculations, create software systems that simulate the processes of movement of a vehicle (MV). As a result, it became possible to significantly increase the accuracy of forecast calculations [3].
The main reason for the unprofitability of transport enterprises specializing in passenger transportation is the constant rise in the cost of energy carriers with a high-energy intensity of the metro. Therefore, the introduction of energy-saving technologies is of particular importance.
The main one of the most important tasks at present is to improve the operational indicators of the city Metro, which contribute to: • reducing the cost of equipment maintenance; • increasing its reliability; • the emergence of an opportunity to significantly reduce energy consumption during conversion.

Directions of modernization of the substation, contributing to the improvement of technical and economic indicators
Solving these problems requires considering the equipment (converter) as a complex technical system that needs to be modernized in the following areas, taking into account the specifics and modes of operation, the specifics and possible types of failures: • Increase in phasing; • As a result of a patent search, circuitry solutions for TRU with 24-fold rectified voltage ripple were found, which allow to reduce active power losses in transformer equipment and valve structure and to increase the stabilizing properties of rectified voltage.
Currently, the overwhelming majority of TRU is outdated, not only in terms of energy saving, but also in terms of reliability and performance. In this paper, the possibility of upgrading the TRU by using the circuitry solutions of the TRU with multiple ripple of the rectified voltage is considered.
The authors proposed the use of 24-pulse TRU. The schematic diagram of a 24-pulse circular TRU synthesized using the method of rotating vector diagrams contains two identical 12-pulse TRU [4]. Figure 2 shows a vector diagram of a 24-pulse ring modular TRU with a series connection of TRU. Figure 2 presents in the form of amplitude-phase portraits (APP) of the voltages of the secondary windings, which make up two six-phase systems of symmetric voltages by vector diagrams deployed on the phase plane. The applied six-phase EMF systems determine the topology of constructing vector diagrams and form their amplitude-phase characteristics. Gate windings "star" and "triangle" with the ratio of turn numbers 1 to 1/ 3 provide the formation of the resulting voltages, the modules of the vectors, which are equal to 30 e. hail on the phase plane, are shifted relative to each other. Then we fix the first system voltage diagram, and rotate the second voltage diagram of the second system around it, thus we get 24 resulting voltage vectors for one period of the mains voltage. For each fixed position on the phase plane of voltage systems, we determine the elements of the valve structure, as well as the order of operation of the valves and secondary windings [5]. The four positions of the rectifier unit systems do not show the order of the formation of the vectors of the resulting stresses S1-S2, S9-S10.S15-S16, S23-S24.
According to the principle of operation of the TRU (Figure 2) and from the features of the formation of the resulting voltages according to the vector diagrams of the voltages of the EMF sources (Figure 2), the alternation of the connection of the load current flow circuits for all twentyfour phases of the rectifying process is shown in Table (Table 1 and Figure 2), it was determined that for the period of the rectified voltage of the group: valve anodes (1, 2, 3, 13, 14, 15) and valve cathodes (10,11,12,22,23,24) have a conductivity angle of 120 el. hail .; the conductivity angles of the valves of the ring group are 900 el. hail. (for valves 7,8,9,19,20,21) and 30 el. hail. (for valves 4,5,6,16,17,18).
When braking, energy is recovered to the drive.