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Voltage in the contact wire. History of railway electrification
The power supply system of an electrified railway consists of the external part of the power supply system, which includes devices for generating, distributing and transmitting electrical energy to traction substations (exclusively);
The traction part of the power supply system, consisting of traction substations of linear devices and a traction network. The traction network, in turn, consists of a contact network, a rail track, supply and suction lines (feeders), as well as other wires and devices connected along the length of the line and catenary directly or through special autotransformers.
The main consumer of electrical energy in the traction network is the locomotive. Due to the random arrangement of trains, random combinations of loads are inevitable (for example, passing trains with a minimum interval between trains), which can significantly affect the operating modes of the traction power supply system.
Along with this, trains moving away from the traction substation are powered by electrical energy at a lower voltage, which affects the speed of the train and, as a result, the throughput of the section.
In addition to the traction engines that drive the train, locomotives have auxiliary machines that perform various functions. The performance of these machines is also related to the voltage level at their terminals. It follows that in traction power supply systems it is very important to maintain a given voltage level at any point in the traction network.
The electrified section of the railway is powered by the power grid of a specific region. A schematic diagram of the power supply of an electrified railway is shown in Fig. 1.3.
The external power supply system (I) includes an electrical station 1, a transformer substation 2, a power line 3. The traction power supply system (II) contains a traction substation 4, supply feeders 5, a suction feeder 6, contact network 7 and traction rail 9 (see Fig. 1.3), as well as linear devices.
Electricity supply railways carried out via lines 35, 110, 220 kV, 50 Hz. The traction power supply system can be either permanent or alternating current.
Rice. 1.3. Schematic diagram of the power supply of an electrified railway: 1 - district power station; 2 - increasing transformer substation; 3 - three-phase power line; 4 - traction substation; 5 - supply line (feeder); 6 - suction line (feeder); 7 - contact network; 8 - electric locomotive; 9 - rails
On Russian railways, a DC power supply system with a contact line voltage of 3 kV and an alternating current power supply system with a contact line voltage of 25 kV and 2 × 25 kV, with a frequency of 50 Hz, have become widespread.
The length of electrified railways in Russia as of January 1, 2005 was 42.6 thousand km.
3 kV DC traction power supply system
The power supply diagram for an electrified section of a DC railway is shown in Fig. 1.4.
The traction network is powered in most cases from 110 (220) kV buses through a step-down transformer, which reduces the voltage to 10 kV. A converter is connected to the 10 kV buses, which consists of a traction transformer and a rectifier. The latter provides conversion of alternating current into constant voltage on 3.3 kV busbars. The contact network is connected to the “plus bus”, and the rails to the “minus bus”.
Rice. 1.4. Schematic diagram of the power supply of an electrified section of a direct current railway with a voltage in the contact network of 3 kV
The fundamental feature of a DC traction power supply system is the electrical connection of the traction motor with the contact network, i.e. there is a contact current collection system. Traction motors for electric locomotives and DC electric trains are designed for a rated voltage of 1.5 kV. The pairwise series connection of such motors allows a voltage of 3 kV in the traction network.
The advantage of a DC system is determined by the quality of a serial DC motor, the characteristics of which better meet the requirements for traction motors.
The disadvantages of the DC traction power supply system are the following:
Due to the low voltage in the traction network, current loads and large losses of electricity (the total efficiency of the DC electric traction system is estimated at 22%);
At high current loads, the distance between traction substations is 20 km or less, which determines the high cost of the power supply system and high operating costs;
Large current loads determine the need to have a contact suspension of a larger cross-section, which causes a significant overconsumption of scarce non-ferrous metals, as well as an increase in mechanical loads on the contact network supports;
The DC electric traction system is characterized by large losses of electrical energy in the starting rheostats of electric locomotives during acceleration (for suburban traffic they amount to approximately 12% of the total electrical energy consumption for train traction);
With direct current electric traction, intense corrosion of underground metal structures occurs, including contact network supports;
Six-pulse rectifiers, which were used until recently at traction substations, had a low power factor (0.88 ÷ 0.92) and, due to the non-sinusoidality of the current consumption curve, caused a deterioration in the quality of electrical energy (especially on 10 kV buses).
On DC roads, a distinction is made between centralized and distributed power supply schemes. The main difference between these schemes is the number of rectifier units at substations and methods of power reservation. With a centralized power supply scheme, there must be at least two units at the substation. In the case of distributed power, all substations are single-unit, and the distance between traction substations is reduced.
There is a requirement that in cases of failure of one unit, normal movement sizes are ensured. In the first scheme, additional (backup) units are used for redundancy, and in the second, there is a conscious refusal to redundant substation equipment by units and a transition to redundancy of entire substations.
The length of electric railways, electrified using a direct current system with a traction network voltage of 3 kV, as of January 1, 2005, amounted to 18.6 thousand km.
Single-phase alternating current traction power supply system with voltage 25 kV, frequency 50 Hz
On railways electrified with alternating current, the most widely used power supply system is 25 kV, 50 Hz. The schematic diagram of the power supply of the electrified section is shown in Fig. 1.5.
Rice. 1.5. Schematic diagram of the power supply of an electrified section of an AC railway with a voltage in the contact network of 25 kV, a frequency of 50 Hz
The traction network is powered from 110 (220) kV buses through a step-down (traction) transformer.
It has three windings:
I - high voltage winding 110 (220) kV;
II - low (medium) voltage winding 27.5 kV for powering the contact network;
III - medium (low) voltage winding 35.10 kV for powering non-traction consumers.
Contact network feeders are connected to the 27.5 kV buses. In this case, phases A and B feed different arms of the traction substation. To separate the phases, a neutral insert is installed on the contact network. Phase C is connected to the rails.
The fundamental feature of the AC traction power supply system - the electromagnetic connection of the traction motor with the contact network - is provided through an electric locomotive transformer.
Advantages of the system:
Independent voltage modes have been established in the contact network and on the traction motor while maintaining the DC traction motor;
The voltage in the contact network was increased to 25 kV AC. As a result, the load current decreases with the same transmitted power; voltage and power losses are reduced;
The distance between traction substations has been increased and their number has been reduced (two to three times);
The construction period has been reduced and the rate of electrification has been increased;
Reduced consumption of non-ferrous metals.
Disadvantages of the AC traction power supply system:
Asymmetrical operating mode of three-phase transformers (for a two-leg load) and, as a consequence, deterioration in the quality of electrical energy and a significant reduction in their available power. Note that the available power of a transformer operating in an asymmetrical mode is understood as the power corresponding to the positive sequence current at such a load when the current in one of the phases of the transformer takes on the rated value;
Non-sinusoidality of the system of consumed currents and also deterioration in the quality of electrical energy in the power supply system (the curve of the current consumed by electric locomotives with a two-pulse rectifier installed on them contains negative higher harmonics 3, 5, 7 with a large numerical value);
Low power factor of AC electric locomotives. The efficiency of the electric traction system as a whole is estimated at 26%;
The AC traction network is a source of electromagnetic influence on adjacent devices, including communication lines, which determines the need for special measures aimed at reducing electromagnetic influence;
The presence of equalizing currents in a two-way AC traction network power supply circuit, and therefore additional large losses of electrical energy.
The length of electric railways, electrified using an alternating current system with a traction network voltage of 25 kV and a frequency of 50 Hz, as of January 1, 2005, amounted to 24.0 thousand km.
Scheme of external power supply of traction substations for DC and AC electric traction systems
The power supply schemes for electrified railways from the power grid are very diverse. They largely depend on the electric traction system used, as well as on the configuration of the power system itself.
Let's consider the basic power supply diagrams for electric traction systems with direct (Fig. 1.6) and alternating (Fig. 1.7) current.
Typically, a 50 Hz transmission line is powered by the utility grid and is located along the railroad.
The voltage of an electric traction system is understood as the rated voltage for which electric rolling stock (EPS) is manufactured. It is also the rated voltage in the contact network; the voltage on the substation buses is usually taken 10% higher than this value.
In Fig. 1.6 and 1.7 are indicated: 1 - power system; 2 - power line; 3 - traction substations (with rectifiers, DC substations and transformer - AC substations); 4 - contact network; 5 - rails; 6 - electric locomotive.
Rice. 1.6. Schematic diagram of DC railway power supply
Rice. 1.7. Schematic diagram of AC railway power supply
Electrified railways belong to the first category of consumers. For such consumers, power is provided from two independent sources of electricity. These are considered to be separate district substations, different sections of busbars of the same substation - district or traction. Therefore, the power supply circuit for traction substations from the power system must be such that failure of one of the district substations or transmission lines could not cause the failure of more than one traction substation. This can be achieved by choosing a rational power supply scheme for traction substations from the power system.
Schemes for connecting traction substations to linespower transmission
The power supply diagram for traction substations from power lines is shown in Fig. 1.8.
Figure 1.8. Scheme of two-way power supply of traction substations from a double-circuit power line
In general, the power supply circuit for traction substations depends on the configuration of the regional network, the power reserve of electrical stations and substations, the possibility of their expansion, etc. In all cases, for greater reliability, they strive to have a two-way power supply circuit for traction substations (see Fig. 1.8). In Fig. 1.8. marked: 1 - support traction substation (at least three inputs of high-voltage lines). Equipped with a complex of high-voltage switching devices and automatic damage protection devices; 2 - intermediate soldering substation. High-voltage switches are not installed, thereby reducing the cost of the power supply system; 3 - intermediate transit substation, sectioning of high-voltage lines is provided for repair or shutdown in case of damage.
Ensuring the reliability of the power supply system is achieved by: using a double-circuit high voltage line, providing two-way power to each power line network, sectioning power lines at transit substations, and having high-speed automatic protection at support, transit traction and district substations.
Ensuring the efficiency of the power supply system is achieved by reducing high-voltage equipment (switches) through intermediate substations that do not have such switches. In the event of damage at these substations, high-speed protection switches off the lines at the reference substations, and during a dead time - at the intermediate ones. Undamaged substations are switched on by an automatic restart system.
When powered from a single-circuit transmission line, connecting substations on taps is not allowed. All substations are included in the line section, and at each substation the intermediate transmission lines are sectioned by a switch.
Features of single-phase current traction network power supply circuitsindustrial frequency
On single-phase alternating current roads, the traction network is powered from a three-phase electrical energy transmission line through transformers, the windings of which are connected in one circuit or another.
On domestic railways, three-phase three-winding transformers are mainly used, connected according to the “star-star-delta” circuit, type TDTNGE (three-phase, oil, with forced cooling - blowing, three-winding, with voltage regulation under load, lightning-proof, for electric traction) with a power 20, 31.5 and 40.5 MV?A. Primary voltage - 110 or 220 kV, secondary traction - 27.5 kV, for regional consumers - 38.5 and 11 kV.
To power only the traction load, three-phase two-winding transformers of the TDG and TDNG types with a star-delta winding connection circuit (-11) are used. The power of these transformers is the same as that of three-winding transformers. Connecting the traction winding with a “triangle” allows you to obtain a flatter external characteristic. One vertex of the “triangle” is connected to the rails, and the other two to different sections of the contact network.
The power supply diagram for a single-phase alternating current traction network from a three-phase transformer with a star-delta winding connection is shown in Fig. 1.9.
When supplying a traction load from three phases, the sections of the traction network to the left and right of the substation must be powered from different phases. Therefore, they have voltages that are out of phase with each other.
Rice. 1.9. Power supply diagram for a single-phase alternating current traction network from a three-phase transformer with a star-delta winding connection
Phase currents can be obtained directly from Kirchhoff's equations. If at the given moment in time the load is l to the left of the substation and p to the right (see Fig. 1.9), then we can write:
Ac = ba + l; (1.1)
Ba = cb + n; (1.2)
Cb = ac - l - p; (1.3)
Ac + ba + cb = 0. (1.4)
From equation (1.4) it follows:
Ba = - ac - cb . (1.5)
We substitute expression (1.5) into equation (1.1):
Ac = - ac - cb + l. (1.6)
Substituting formula (1.3) into expression (1.6), we obtain:
Ac = - ac - ac + l + n + l;
3 ac = 2 l + n;
Ac = l + n. (1.7)
Substituting formula (1.7) into expression (1.3), we obtain:
Cb = l + n - l - n;
Cb = - l - p. (1.8)
Substituting formula (1.8) into expression (1.2) we get:
Cb = - l - n + n;
Ba = - l + p. (1.9)
The current in the phases of the secondary “triangle” and, accordingly, in the phases of the primary winding can also be found by constructing a vector diagram.
To construct a vector diagram, it is assumed that the currents of the feeder zones l and p, which mean the total currents of the feeders leaving the substation to the left and right, respectively, are distributed between the secondary windings of the transformer. In other words, you need to determine the share of participation secondary winding transformer in the power supply of both feeder zones.
When the transformer windings are connected according to the diagram and there are no zero-sequence currents in a closed delta circuit, each phase can be considered independently of the other, i.e., as a single-phase transformer. In this case, the distribution of loads on the secondary side between the phases is determined only by the ratio of the winding resistance values. The left feeder zone with current l is powered by voltage U ac. This voltage is generated both in the windings “a” and in the windings “bу” and “cz”. The resistance of the windings “ah” is half the resistance of the other two windings connected in series. Consequently, the current l is divided between these voltage-generating ac windings in a ratio of 2:1. The current is divided in the same way.
Let's construct a vector diagram to determine the phase currents of a three-phase transformer (Fig. 1.10).
Rice. 1.10. Vector diagram for determining the phase currents of a three-phase transformer
Let us depict on the diagram the vectors of voltages and currents I l, I p. The current in the windings “ah”, based on the above, should be equal to the sum of l and p. Setting aside on the vector I l a value equal to its length, on the vector I p its length, we find ac as the sum of these parts. The current in phase A of the “star” of the primary winding (if we take the transformation ratio equal to unity and the no-load current equal to zero) will be equal to the current a.
Similarly, the current in the winding “cz” is the sum of p and - l. Adding them up, we get the current c. Accordingly, c = C.
The load in the “by” winding is made up of the sum - l and p. By adding the vectors, we get the load of the third least loaded phase b = B. Note that the least loaded phase is the “triangle” phase that is not directly connected to the rails.
In the diagram fig. Figure 1.10 shows the phase shift angles A, B, C between current I A, I B, I C and voltage U A, U B, U C. Note that A > L, and C< П, т. е. углы сдвига А и С для двух наиболее загруженных фаз оказываются разными (даже для Л = П). У «опережающей» (по ходу вращения векторов) С угол меньше, чем у «отстающей» фазы А. Это существенно влияет на потери напряжения в трансформаторе.
To ensure uniform loading of power transmission line phases, they are alternated when connected to traction substations.
Connection diagrams for a group of traction substations to a power line
The requirements for the connection diagram are as follows:
Ensuring the possibility of parallel operation on the contact network of adjacent traction substations;
Creating uniform loading of power lines.
If the power supply of the power line is one-way, then a cycle of three substations with different phase rotation ensures their uniform load in the area between the source of electrical energy and the first substation (Fig. 1.11). The power station generators will operate in normal symmetrical load mode. Transmission line voltage power losses are reduced due to reduced load unevenness.
Let's consider the diagrams for connecting traction substations to power lines (see Fig. 1.11).
Substation No. 1. In this case, the transformer terminal “A t” is connected to phase A, and the other two - “B t” and “C t” - to phases B and C, respectively. With this connection, the substation is designated type I. Let's construct a vector diagram for this substation (Fig. 1.12).
Lagging phase ac > a. Consequently, the current I ac is shifted by the current I b of the adjacent arm towards the lag. Reactive power consumption increases (in the lagging phase), which leads to a decrease in voltage in it.
Leading phase cb< b . Следовательно, ток I a сдвигает вектор тока I cb в сторону опережения. Потребление реактивной мощности снижается, напряжение увеличивается.
From the above it follows that of the three phases, one is less loaded - the middle one - B.
Substation No. 2. The terminal of the transformer “V t” will not be connected to the phase of the same name, but to phase C, which will be the actual phase. All feeder zones will receive power from points “a” and “b”, but we are no longer free to choose the phase for power supply after we have chosen the power supply circuit from the first traction substation.
Let's build a vector diagram (Fig. 1.13). The phase sequence of the second substation has changed. If the first substation had ABC (type I substation), then the second one became ASV (type II substation). Now the less loaded phase will be phase C.
Substation No. 3. Power supply to the third zone from substation No. 2 is possible only from point “b” (see Fig. 1.11). From substation No. 3, the power supply for this zone should also be from point “b”. Consequently, all odd zones will receive power from points “b” and all even zones from points “a”.
Let's build a vector diagram (Fig. 1.14). The voltage between the contact wires and the rails will be positive in even sections, and negative in odd sections, i.e., either in phase with the voltage of one of the phases of the power line, or opposite to it. For substation No. 3, the less loaded phase is phase A. The sequence of phases will be CAB (type III substation).
Rice. 1.12. Vector diagram of voltages and currents for substation No. 1
Rice. 1.13. Vector diagram of voltages and currents for substation No. 2
Rice. 1.14. Vector diagram of voltages and currents for substation No. 3
The order of alternation of the least loaded phases of the power line will be determined by the number of substations on the site and the power supply circuit of the traction network.
When supplying power lines on both sides, cycles that are multiples of three are used (Fig. 1.15).
Rice. 1.15. Connection to power lines of traction substations different types with two-way power supply
Unfortunately, connecting a group of traction substations to a power transmission line using phase rotation does not solve the entire problem of current and voltage asymmetry. These issues will be discussed separately.
Three-wire traction power supply systemalternating current
This system is a variation of the power frequency AC power supply system, since the locomotive in this case remains the same. As an example, consider a 2 × 25 kV AC traction power supply system with a frequency of 50 Hz.
The power supply diagram for an electrified section of the railway using an AC traction power supply system of 2 × 25 kV is shown in Fig. 1.16.
Fig.1.16. Power supply diagram for an electrified section of the railway using an AC traction power supply system of 2 × 25 kV:
1 - step-down transformers of substation No. 1 and 2 (single-phase) 220/25 kV; 2 - linear autotransformers 50/25 kV with a power of 16 mV?A, installed between substations after 10 - 20 km; 3 - connection of rails at the midpoint of the step-down transformer and linear autotransformer (LAT); 4 - power flow at U = 50 kV; 5 - at U = 25 kV; 6 - electric locomotive
The distance between substations is 60 - 80 km.
The advantages of the system are the following:
Due to the transfer of power to the LAT at a higher voltage (50 kV) in the traction network, power and voltage losses are reduced;
The shielding effect of the 50 kV supply wire makes it possible to reduce the influence of the contact network on adjacent lines.
The mentioned advantages of the system under consideration determine its use on railways with heavy freight traffic and high-speed passenger traffic.
The disadvantages of the system include:
Increase in the cost of electrification due to the installed capacity of LAT;
Complicating the maintenance of the contact network;
Difficulty in voltage regulation.
For the first time, a three-wire AC traction power supply system was used in Japan in 1971. In the Commonwealth countries, in 1979, the first section of the Vyazma - Orsha Belarusian Railway was installed.
Currently, more than 2 thousand km on the Moscow, Gorky and former Baikal-Amur railways have been electrified using this system.
The provided power supply system is discussed in more detail in the works.
Catenary power supply circuits
Depending on the number of supply paths, contact network power supply circuits can be single- or multi-path. In this case, it is possible to use both one-sided and two-sided power supply.
On single-track sections, single-sided separate, cantilever and counter-cantilever power supply schemes have become widespread. Two-way power supply is also used.
On double-track sections - separate, junction, counter-cantilever, counter-ring and parallel supply.
The choice of method of powering the contact network is associated with specific indicators of its operation - reliability and efficiency. Ensuring reliability is achieved by sectioning the contact network and automating the assembly of circuits, efficiency - by reducing electrical energy losses and uniform load of the contact network of individual sections and tracks.
Contact network power supply circuits are shown in Figures 1.17 and 1.18.
Single track section(see Fig. 1.17). The contact network is divided into two sections (by an insulating interface or a neutral insert), and each section is supplied from the substation through its own feeder. If any section is damaged, only this section is switched off (Fig. 1.17a). With a cantilever scheme (Fig. 1.17,b), the section is powered by one substation on one side. If damaged, power is removed from the entire area. With a back-to-back cantilever scheme (Fig. 1.17, c), the section is powered from one substation on one side. Each section has its own feeder. If one of the substations is disconnected, the site is left without power.
Fig.1.17. Power supply circuits for the contact network of a single-track section
Double track section(see Fig. 1.18). A separate power supply circuit (Fig. 1.18a) provides power to each path independently of each other. In this regard, the total cross-section of the catenary system decreases, which leads to an increase in electrical energy losses. At the same time, the reliability of this power supply circuit is higher compared to other circuits. The nodal power supply circuit (Fig. 1.18b) is performed using partitioning posts. In this case, electrical energy losses are reduced due to a possible increase in the cross-section of the catenary. If the contact network is damaged, not the entire inter-substation zone is excluded from operation, but only the damaged area between the substation and the sectioning post.
Fig.1.18. Power supply circuits for the contact network of a double-track section
The console circuit (Fig. 1.18, c) provides power to each path separately from different substations. The disadvantages here are the same as in a similar single-track section design. The back-to-back cantilever circuit (Fig. 1.18d) makes it possible to divide the inter-substation zone into sections that are not electrically connected to each other. Each path is fed by its own feeder. When the feeder is disconnected, the area is without voltage. Electrical energy losses increase.
The counter-ring circuit (Fig. 1.18, d) allows sections along the ring to be powered from two substations, which reduces electrical energy losses and increases reliability. The parallel power supply circuit (Fig. 1.18e) is most widespread. With this scheme, the contact network is powered by two substations on both sides. Since the contact suspension of both paths is electrically connected to each other, its cross-section increases, which leads to a decrease in electrical energy losses. At the same time, the parallel power supply circuit is highly reliable compared to other circuits.
On domestic railways, the parallel power supply circuit is accepted as the main one.
2. Power supply systems for electric railways, railway transport enterprises and their operating modes.
2.1 Brief history and current state of railway electrification.
2.1.1 History of electric traction.
The first electric railway was demonstrated in 1879 by Siemens in Berlin at an industrial exhibition. An electric locomotive with a power of 2.2 kW carried three cars with 18 passengers. In St. Petersburg in 1880, experimental trips of a 40-seater carriage with a 3 kW electric motor were carried out. In 1881, the first tram line began operating in Berlin. In Russia, the first tram was launched in 1892. The first section of the railway with electric locomotive traffic was opened in the USA in 1895.
2.1.2 The main stages of electrification of railways in Russia. Electrification plans.
The electrification of Russian railways was outlined by the State Electrification Plan (GOELRO) in 1920. The first electric railway in DC with a voltage of 3 kV Baku - Sabunchi was launched in 1926. In 1932, the first electric locomotives went through the Suram Pass in the Caucasus. By 1941, 1865 km were electrified. During the Great Patriotic War of 1941 - 1945, the electrification of railways continued: sections Chelyabinsk - Zlatoust, Perm - Chusovskaya, etc. The electrified section Murmansk - Kandalaksha worked stably in the front zone.
The master plan for the electrification of the USSR railways was adopted in 1956. Since this year, the pace of introduction of electric traction has increased significantly.
The pace of electrification in the USSR was:
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Kilometers |
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At the beginning of 1991, 55.2 thousand km were electrified. Of the 147,500 km of railways in the USSR, this accounted for 37.4%. The volume of transportation on electric railways was 65%. Thus, 1/3 of the railways are electrified, and 2/3 of freight is transported on them. As a rule, the most heavily loaded areas were electrified. This ratio of railway electrification and transported goods indicates the significant efficiency of railway electrification.
Length of electrified railways by year:
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Total, thousand km |
On alternating current, thousand km |
Length, in % of total length |
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Across Russia | |||
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Electrification plans | |||
The following railway lines operate on electric traction:
Vyborg – St. Petersburg – Moscow – Rostov on Don – Tbilisi – Yerevan, Baku – 3642 km.
Moscow - Kyiv - Lviv - Chop - 1765 km.
Moscow – Samara – Ufa – Tselinograd – Chu – 3855 km.
Brest – Minsk – Moscow – Sverdlovsk – Omsk – Irkutsk – Chita – Khabarovsk – Vladivostok – 10,000 km. In 2002, the electrification of Transib was completed.
Ufa – Chelyabinsk – Omsk – Irtyshskaya – Altaiskaya – Abakan – Taishet – Severobaikalsk – Taximo
Until 1956, electrification of railways was carried out exclusively on direct current, first with a voltage of 1.5 kV, then 3 kV. In 1956, the first section was electrified using alternating current with a voltage of 25 kV (section Ozherelye - Pavelets of the Moscow road).
The stage of converting 3 kV direct current electric traction to 25 kV alternating current has begun.
In November 1995, for the first time in world practice, the main section of the Zima-Slyudyanka railway, 434 km long, was transferred from direct current with a voltage of 3 kV to alternating current with a voltage of 25 kV. At the same time, two docking stations were eliminated. This made it possible to increase the weight of freight trains. A single continuous highway Mariinsk - Khabarovsk with a length of 4812 km and 2002 to Vladivostok, electrified via a 25 kV AC power supply system, was created. In October 2000, the Loukhi-Murmansk section with branches (490) km of the Oktyabrskaya Railway was switched to alternating current.
Statistical information on the electrification of Russian railways:
by length: diesel traction – 53.2%, electric traction – 46.8%;
by volume of transportation: diesel traction – 22.3%, electric traction 77.7%;
by type of current: direct current with a voltage of 3 kV - 46.7%, alternating current with a voltage of 25 kV - 53.35%;
Share of electrified railways in Russia in the world:
by length of the total world railway network: Russia – 9%, other countries of the world – 91%;
by length of electrified railways: Russia - 16.9%, other countries of the world - 83.1%.
The program for the electrification of railways and switching freight flows from diesel locomotives to electrified ones provides for the electrification of 7,640 km and the transfer of approximately 1,000 km of railway lines from direct current to alternating current in the period from 2001 to 2010. At the same time, 90% of new electrification is carried out on alternating current and only some branches on direct current. By 2010, Russia will have 49.1 thousand km of electrified lines. This will amount to 56.7% of the total length of the railway network, with 81.2% of the total volume of transportation carried out on it. Russia will fall into the area of the most optimal use of electric traction
The introduction of electric traction has the following stages:
1.Electrification of suburban areas using direct current voltage of 1.5 kV;
2.Electrification of main sections of the railway with a voltage of 3 kV and transfer of suburban sections to a voltage of 3 kV.
3.Introduction of alternating current with a voltage of 25 kV along with the expansion of the landfill of direct current with a voltage of 3 kV. A reliable system for connecting two types of current by sectioning the contact network has been developed.
4. Introduction of a three-wire autotransformer power supply system of high voltage 2x25 kV and reduction of electrification at direct current 3 kV.
5. Conversion of DC sections to alternating current.
In the last quarter of the 19th century. the contours of new directions in locomotive construction - electric and diesel locomotive construction - were outlined.
The possibility of using electric traction on railways was pointed out back in 1874 in an application for a privilege by the Russian specialist F.A. Pirotsky. In 1875-1876 He conducted experiments on the Sestroretsk railway on the transmission of electricity along rails isolated from the ground. The transmission was carried out over a distance of about 1 km. The second rail was used as a return wire. The electrical energy was transferred to a small engine. In August 1876, F.A. Pirotsky published an article with the results of his work in the Engineering Journal. These experiments gave him the idea of using electricity to power trolleys moving on metal rails.
The practical implementation of the idea of using electric energy in transport belongs to Werner Siemens (Germany), who built the first electric railway, exhibited at the Berlin Industrial Exhibition in 1879. It was a small narrow-gauge road intended for walking by visitors to the exhibition. The short train of open carriages was driven by an electric locomotive with two motors that received 150 V direct current from an iron strip laid between the rails. One of the running rails served as the return wire.
In 1881, W. Siemens built a test section of an electric railway in the Berlin suburb of Lichterfeld, using a motor car for the first time. A current of 180 V was supplied to one of the running rails, and the other rail served as a return wire.
In order to avoid large losses of electricity that arose due to the poor insulating ability of wooden sleepers, V. Siemens decided to change the electrical circuit for powering the electric motor. For this purpose, a suspended working wire was used on the electric road built in the same 1881 at the Paris World Exhibition. It represented an iron tube suspended above the rails. The lower part of the tube was equipped with a longitudinal slot. Inside the tube there was a shuttle connected through a slot to a flexible wire, which was attached to the roof of the locomotive and transmitted electric current to the electric motor. The same tube, suspended next to the first, served as a return wire. A similar system was used on those built in 1883-1884. suburban trams Mödling - Vorderbrühl in Austria and Frankfurt - Offenbach in Germany, operating at a voltage of 350 V.
Around the same time, in Kinresh (Ireland), a tram line introduced current wiring along a third rail, which was installed on insulators next to the running rails. However, this system turned out to be completely unacceptable in the city, interfering with the movement of carriages and pedestrians.
It is interesting to note that the technical doom of such a system for supplying electric current to the motor was foreseen earlier by F.A. Pirotsky, who wrote in 1880 in the newspaper “St. Petersburg Vedomosti”: “The electric railway I built is the simplest and cheapest. It does not require the cost of a middle rail line, which needlessly increases the cost of the road by 5% and stops carriage traffic in the city. It does not require the expenditure of cast iron poles, which are prohibitively expensive.”
This letter was published by Pirotsky in connection with reports that appeared in the press about the results of his tests of an electric tram on September 3, 1880 in St. Petersburg. At this time, F.A. Pirotsky was intensively engaged in the implementation of his projects related to the creation of reliable urban electric transport. He understood that the development of mainline railway electric transport is impossible without solving the fundamental problem of electrical engineering - the transmission of electricity over long distances. Taking this into account, F.A. Pirotsky concentrated his attention on experiments in the electric propulsion of a car, adopted on urban horse-drawn railways. As a result, in 1880 he managed for the first time to carry out movement on the rails of a real double-decker motor car. F. A. Pirotsky presented the results of his work in 1881 at the International Electrical Exhibition in Paris, where he exhibited his electric railway scheme.
In 1884, in Brighton (England), an electric railway powered by one of the rails with a length of 7 miles was built according to Pirotsky’s scheme. The operation of only one carriage gave a net profit, compared with horse-drawn 420 francs per day.
Since the mid-80s of the XIX century. American engineers and entrepreneurs began to actively develop electric traction on railways, and they energetically began to improve electric locomotives, as well as methods for supplying current.
T. A. Edison worked on the problem of electric railway transport in the USA, building three small experimental lines from 1880 to 1884. In 1880, he created an electric locomotive, which in its appearance resembled a steam locomotive. The electric locomotive was powered by electric current from the track rails, one of which was connected to the positive and the other to the negative pole of the generator. In 1883, T. A. Edison, together with S. D. Field, built a more advanced electric locomotive (“The Judge”), which was exhibited at an exhibition in Chicago and later in Louisville.
The work of the American engineer L. Daft dates back to 1883, who created the first mainline electric locomotive (“Atreg”) for standard gauge, intended for the Saratoga-McGregor Railway. In 1885, Daft built an improved model of an electric locomotive for the New York Trestle Railroad. The locomotive, named "Benjamin Franklin", weighed 10 tons, was more than 4 m long and was equipped with four driving wheels. An electric current of 250 V was supplied along the third rail to a 125 hp motor. s, which could pull an eight-car train at a speed of 10 mph (16 km/h).
In 1884, the Swiss engineer R. Tory built an experimental gear railway, using it to connect a hotel located on a mountain slope with the town of Terry (not far from Montreux on Lake Geneva). The locomotive had four driving wheels and moved along a very steep incline (1:33). Its power was small and allowed it to carry four passengers at a time. On a descent during braking, the motor worked as a generator, returning electrical energy to the network.
For a number of years, engineering has worked tirelessly to improve the technology for supplying current to an electric locomotive.
In 1884, in Cleveland, Bentley and Knight built a streetcar with an underground wire. A similar system was introduced in 1889 in Budapest. This method of power supply turned out to be inconvenient to use, since the gutter quickly became dirty.
At the end of 1884, in Kansas City (USA), Henry tested a system with copper overhead wires, one of which was forward, the other was reverse.
The construction of the first tram with one overhead working wire by the Belgian specialist Van Depoel in Toronto (Canada) dates back to 1885. In his scheme, the running rails served as the return wire. Along the line, poles with consoles were built, to which insulators with a working wire were attached. Contact with the working wire was carried out using a metal roller mounted on the tram bar, which “rolled” along the wire while moving.
This suspension system proved to be very rational, after further improvement it was adopted in many other countries and soon became widespread. By 1890, about 2,500 km of tram-type electric roads were in operation in the United States, and by 1897, 25 thousand km. The electric tram began to displace old types of urban transport.
In 1890, an overhead wire appeared for the first time in Europe on a tram line in Halle (Prussia). Since 1893, electric railways in Europe have been developing at an accelerated pace, as a result of which by 1900 their length had reached 10 thousand km.
In 1890, electric traction was used on the built underground London road. An electric current of 500 V was supplied to the electric motor using a third rail. This system turned out to be very successful for self-supporting roads and began to quickly spread in other countries. One of its advantages is the possibility of electrifying roads with very high energy consumption, which included subways and mainline railways.
In 1896, electric traction using a live third rail was first introduced on the Baltimore and Ojai Railroad. Electrification affected a 7 km section of the road on the approach to Baltimore. A 2.5-kilometer tunnel was built along this section of the route, prompting builders to electrify it. Electric locomotives operating on this section received electrical energy from the third rail at a voltage of 600 V.
The first electrified railways were small in length. The construction of long-distance railways encountered difficulties associated with large energy losses caused by the transmission of direct current over long distances. With the advent of alternating current transformers in the 1980s, which made it possible to transmit current over long distances, they were introduced into railway power supply circuits.
With the introduction of transformers in the power supply system, the so-called “three-phase direct current system” was formed, or, in other words, “a direct current system with three-phase power transmission.” The central power station generated three-phase current. He transformed into high voltage(from 5 to 15 thousand V, and in the 20s - up to 120 thousand V), which was supplied to the corresponding sections of the line. Each of them had its own step-down substation, from which alternating current was directed to an alternating current electric motor mounted on the same shaft with a direct current generator. The working wire was supplied with electricity from it. In 1898, a significant length railway with an independent track and a three-phase current system was built in Switzerland and connected Freiburg-Murten-Ins. This was followed by the electrification of a number of other sections of railways and subways.
By 1905, electric traction had completely replaced steam on underground roads.
Shukhardin S. "Technology in its historical development"
The first possibilities of equipping the railway with electric traction were discussed in 1874. Russian specialist F.A. During this period, Pirotsky conducted the first practical experiments on the railway tracks near Sestroretsk on the possibility of transmitting electrical energy through the use of rails isolated from the ground.
The first attempts to equip with electric traction
The work was carried out over a distance of one kilometer. The second rail served as a return wire. The resulting electrical energy was fed to a small engine. Two years later, after the start of the work, specialist F.A. Pirotsky is publishing an article about the results obtained in one of the technical engineering journals. The end result was that he tested the launch of trolleys moving along railway tracks using the generated electricity.
First practical application
Werner Siemens, living in Germany, carried out the practical application of electricity on the railway. The Berlin Industrial Exhibition of 1879 exhibited this achievement on its premises in the form of a narrow-gauge road, on which guests of the exhibition had the honor of traveling. The train consisted of several open cars, which were pulled by an electric locomotive. Its movement was provided by two motors powered by direct current; a voltage of one hundred and fifty volts was provided by an iron strip located in the space between the rails. One of the running rails served as a return wire.
Test plot
Two years later, in the Berlin suburban part of Lichterfeld, the inventor W. Siemens completed the construction of trial railway tracks, provided with electrical power, and a carriage equipped with a motor moved along them. The current voltage was one hundred and eighty volts and was supplied to one running rail - this was, as it were, a return wire.
To eliminate the possible large loss of electrical energy due to poor insulation due to the use of wood sleepers for this purpose, engineer Werner Siemens had to change schematic diagram supplying power to the electric motor.
First experience of suspended electrification system
The Paris World Exhibition became the platform where people saw an electric road using an overhead working drive. This power supply was in the form of an iron tube suspended above the rail tracks. A longitudinal slit was made at the bottom of the tube. A shuttle moved in the inner part of the pipe, which was connected by means of a flexible wire through an existing slot and attached directly to the locomotive roof surface, thus transmitting current to the electric motor.
A similar tube was suspended nearby, parallel to the first tube, and served as a reverse drive. A similar system was used on trams created in 1884, which appeared on German and Austrian territories in the cities of Offenbach, Frankfurt, Vorderbrühl and Mödling. To ensure tram traffic, a voltage of three hundred and fifty volts was supplied.
In those same years, the Irish city of Kinresh became a kind of platform for innovators who used the third rail as a current conductor on tram lines. It was installed using insulators that stood parallel to the running rails. Unfortunately, this new scheme did not have long-term practical use, since in urban conditions it was a clear obstacle for pedestrians and horse-drawn carriages.
The work of a Russian engineer
The most interesting thing is that Fyodor Apollonovich Pirotsky warned about all these circumstances of technical doom in supplying power to an electric motor in one of his works, published in the newspaper edition of St. Petersburg Vedomosti. They stated in plain text that his brainchild in the form of an electric railway was the simplest and cheapest structure. There is no need to incur additional costs for laying the middle rail line, which increases the cost of the project by five percent and interferes with vehicle traffic on city streets. To implement his project, there will be no need to purchase cast iron poles, which cost a lot of money. Subsequently, foreign inventors heeded such a reasonable warning from the Russian engineer and put everything into practice.
Inventor F.A. Pirotsky was actively involved in the implementation of his project, realizing that urban and railway transport had no future without electricity. Based on the results of his new research and testing, a double-decker motor car moving along rail tracks will appear on the streets of St. Petersburg. In 1881, this carriage was exhibited at the Paris exhibition.
The English city of Brighton became a pioneer in the practical implementation of the Russian engineer’s project in 1884. The length of the electric railway, where only one rail was powered, was seven miles. As a result, the net profit of one electric carriage in comparison with a horse-drawn carriage during the working day amounted to four hundred and twenty francs.
Developments of American engineers
On the American continent, they also did not sit idly by, but were actively engaged in improving the method of current supply on an already created electric locomotive.
American researcher T.A. Edison carried out research work to improve the railway locomotive, consuming electricity as fuel. Over a four-year period of time, until 1884, T.A. Edison managed to create three short-length travel lines. The electric version of the created locomotive was more reminiscent of a steam locomotive model. Power was provided by generators. One of the track rails was powered from the negative, the other rail was connected to the positive generator pole. Already in 1883, at the Chicago exhibition, a locomotive, modern for that time, consuming electric current, named “The Judge,” appeared on one of the sites. The creation of this electric locomotive version was carried out in close collaboration with another inventor S.D. Field.
At the same time, the American engineer L. Daft managed to build the first model of a mainline electric locomotive, named “Atreg”. The locomotive used standard gauge railroad tracks on the route from McGregor to Saratoga. Subsequently, L. Daft managed to improve the technical qualities of his own locomotive version, but now it is called “Benjamin Franklin”, its mass is ten tons, length is four meters. There were four driving wheels. The supply of electric current, whose voltage was two hundred and fifty volts, was carried out through the third rail, which ensured the operation of a motor whose power reached one hundred and twenty-five horsepower. There were enough of them for the train to have eight cars, and they followed, driven by an electric locomotive at a speed of sixteen kilometers per hour.
Swiss Gear Road
In the same 1884, the Swiss engineer Mr. R. Thorne built an experimental railway with gears. As a result, the village of Tori and the mountain hotel received a transport artery with a steep slope, along which a small electric locomotive with four driving wheels followed. The power parameters were insignificant and allowed the passenger transportation of only four people. Going down the slope, the braking mode was activated, and the electric motor became a generator, delivering the generated electrical energy to the network.
Electrification in Russia
Project
Designers from all countries worked to improve the existing electric locomotive versions, as well as on the technology for supplying electricity to the locomotive.
Electrification went its own way in the Russian Empire. The project on how to electrify the first domestic railway appeared at the very end of the nineteenth century, in 1898. But to begin construction of Oranienbaumskaya electric line from St. Petersburg to Krasnye Gorki was possible only in 1913. It was not possible to implement the existing plans in full due to the outbreak of the First World War. As a result, limited sections of the road became a city tram route. In Strelna, trams still follow the tracks today.
In the post-revolutionary period, the young government of the RSFSR initiated the development of the well-known GOELRO plan and approved it in 1921. The electrification of the tracks was to be carried out in ten to fifteen years. The length of the new tracks under the project was three thousand five hundred kilometers, covering only a small part of the most important directions.
Beginning of work
The first railways with electric traction appeared in 1926 on the route: from Surakhani to Sabunchi and further to the capital of Azerbaijan - Baku. Three years later, electric trains master the suburban route from Moscow-Pasazhirskaya to Mytishchi along the Northern Railway.
A little more time passed, and in 1932 the Suramsky pass section received electricity. Now, mainline traffic on this road was provided by electric locomotives. The electric traction system used direct current, the voltage of which reached three thousand volts. In subsequent years, it was widely used on the railways of the Soviet Union. The first days of electric locomotive operation clearly demonstrated their advantage over steam locomotive traction. These indicators were productivity and energy efficiency.
By 1941, the length of all tracks provided with electrical energy was one thousand eight hundred and sixty-five kilometers.
Post-war period
In the first post-war year, electrified lines reached a total length of two thousand twenty-nine kilometers. It should be noted that six hundred and sixty-three kilometers of the road were restored, and in fact, practically rebuilt.
There was an active restoration of the production capacity of factories destroyed during the war. A new enterprise is emerging in the city of Novocherkassk, which specializes in the production of electric locomotives. Two years after the war, a Riga enterprise producing electric trains began operating.
We must not forget that in those difficult post-war times, the electrification of railway tracks required significant infusions of funds. Therefore, the volume of growth in electrical tracks was significantly behind the planned plans and amounted to only thirteen percent. There were many reasons for this, starting with scarce funding for the work and ending with the high cost of materials needed to carry out such construction.
50s
In the fifties of the twentieth century, the level of mastered volumes in relation to planned loads was seventy percent.
At the Twentieth Party Congress, the First Secretary of the CPSU Central Committee N.S. Khrushchev harshly criticized the entire leadership of the Ministry of Railways. Some officials were removed from their positions.
One of the tasks of the fifth five-year plan was the construction of new power plant structures that could meet the needs of the electrified railway.
Subsequent master plans required the electrification of forty thousand kilometers of railway lines by 1970.
Building momentum
And again, industrialization helps to achieve an annual development of two thousand kilometers of railways equipped with electricity.
By March 1962, victorious reports appeared about the fulfillment of the planned loads by one hundred and five percent, which in physical terms amounted to eight thousand four hundred and seventy-three kilometers. All this clearly evidenced the previous lag behind the level of desired results.
In the seventies of the twentieth century, they began a massive replacement with semiconductor rectifiers to replace the mercury rectifiers located at substations. Each new substation being built was equipped only with semiconductor equipment. All this meant that the most powerful and reliable inverter units appeared in the Soviet Union. They made it possible to return excess energy that was generated by rolling stock during the period of electric braking to the primary external network.
Safely and quickly turning off the current in a contact wire network has always been difficult and painful, especially during a short circuit.
Finally, powerful switches appeared at railway substations.
They were installed in pairs in a sequential pattern.
Russian period
With the advent of the twenty-first century, there has been a noticeable slowdown in the pace of construction of electrified transport routes in Russian Railways, four hundred and fifty kilometers per year. Sometimes this value dropped to one hundred and fifty kilometers, and sometimes rose to seven hundred kilometers. A significant part of the electrified tracks has been converted to use alternating current. Similar modernization was carried out on the Caucasian, Oktyabrskaya roads and in the Siberian directions.
Sochi 2014
On the eve of the 2014 Winter Olympics, a new electrified railway was immediately built along the route from Adler to Krasnaya Polyana. Today, the Republic of Belarus continues work on the electrification of railway lines on its territory.
With the development of industry and Agriculture country, the amount of cargo that needs to be transported from one region of the country to another is increasing, and this places demands on railway transport to increase the carrying capacity and capacity of railways. In our country, more than half of all freight turnover is carried out using electric traction.
There were no electric railways in Tsarist Russia. The electrification of main highways was planned in the first years of Soviet power during the organization of the country's planned economy.
In the GOELRO plan developed in 1920, attention was paid to increasing the carrying and throughput capacity of railways by converting them to electric traction. In 1926, the Baku-Surakhani line, 19 km long, was electrified with a contact voltage of 1200 V DC. In 1929, the suburban section Moscow - Mytishchi with a length of 17.7 km with a voltage in the contact network of 1500 V was transferred to electric traction. In 1932, the first main section Khashuri - Zestafonn on the Suram Pass of the Caucasus with a length of 63 km with a voltage of 3000 V DC was electrified current After this, the electrification of some of the most severe climatic conditions, the most heavily loaded sections and lines with a heavy profile began.
By the beginning of the Great Patriotic War, the most difficult sections in the Caucasus, the Urals, Ukraine, Siberia, the Arctic and in the suburbs of Moscow, with a total length of about 1900 km, were transferred. During the war, lines were electrified in the Urals, in the suburbs of Moscow and Kuibyshev with a total length of about 500 km.
After the war, sections of electrified railways in the western part of the country, located in territory temporarily occupied by the enemy, had to be restored. In addition, it was necessary to convert new heavy sections of railways to electric traction. Suburban areas, previously electrified at a voltage of 1500 V in the contact wire, were transferred to a voltage of 3000 V. Beginning in 1950, from the electrification of individual sections they switched to converting entire freight-loaded areas to electric traction, and work began on the Moscow-Irkutsk, Moscow lines -Kharkov, etc.
The increase in the flow of national economic goods and the growth of passenger transportation require more powerful locomotives and an increase in the number of trains. With a voltage in the contact network of 3000 V, the currents consumed by powerful electric locomotives, with a significant number of them in the supply area from traction substations, caused large energy losses. To reduce losses, it is necessary to place traction substations closer to one another and increase the cross-section of the contact network wires, but this increases the cost of the power supply system. Energy losses can be reduced by reducing the currents passing through the wires of the contact network, and in order for the power to remain the same, it is necessary to increase the voltage. This principle is used in the electric traction system of alternating single-phase current with an industrial frequency of 50 Hz at a contact network voltage of 25 kV.
The currents consumed by electric rolling stock (electric locomotives and electric trains) are significantly less than with a direct current system, which makes it possible to reduce the cross-section of the overhead wires and increase the distances between traction substations. This system began to be studied in our country even before the Great Patriotic War. Then, during the war, research had to be stopped. In 1955-1956 Based on the results of post-war developments, the Ozherelye-Pavelets experimental section of the Moscow road was electrified using this system. Subsequently, this system began to be widely introduced on the railways of our country along with the direct current electric traction system. By the beginning of 1977, electrified railways in the USSR stretched over a distance of about 40 thousand km, which is 28% of the length of all railways in the country. Of these, about 25 thousand km are on direct current and 15 thousand km are on alternating current.
The railways from Moscow to Karymskaya are over 6,300 km long, from Leningrad to Yerevan - about 3.5 thousand km, Moscow-Sverdlovsk - over 2 thousand km, Moscow-Voronezh-Rostov, Moscow-Kiev-Chop, lines connecting the Donbass with the Volga region and the western part of Ukraine, etc. In addition, suburban traffic in all major industrial and cultural centers has been switched to electric traction.
In terms of the pace of electrification, length of lines, volume of transportation and cargo turnover, our country has left all countries of the world far behind.
Intensive railway electrification caused by its great technical and economic advantages. Compared to a steam locomotive or with the same weight and dimensions, it can have significantly greater power, since it does not have a prime mover (steam engine or diesel engine). Therefore, an electric locomotive ensures operation with trains at significantly higher speeds and, consequently, increases the throughput and carrying capacity of railways. The use of control of several electric locomotives from one station (a system of many units) makes it possible to increase these indicators to an even greater extent. Higher travel speeds ensure faster delivery of goods and passengers to their destination and bring additional economic benefits to the national economy.
Electric traction has a higher efficiency compared to diesel and especially steam traction. The average operational efficiency of steam traction is 3-4%, diesel traction is about 21% (with 30% use of diesel power), and electric traction is about 24%.
When an electric locomotive is powered from old thermal power plants, the efficiency of electric traction is 16-19% (with the efficiency of the electric locomotive itself being about 85%). Such a low efficiency of the system with a high efficiency of the electric locomotive is obtained due to large energy losses in the furnaces, boilers and turbines of power plants, the efficiency of which is 25-26%.
Modern power plants with powerful and economical units operate with efficiency up to 40%, and efficiency electric traction when receiving energy from them is 25-30%. The most economical operation of electric locomotives and electric trains is when the line is powered from a hydraulic station. At the same time, the efficiency of electric traction is 60-62%.
It should be noted that steam and diesel locomotives run on expensive and high-calorie fuel. Thermal power plants can operate on lower grades of fuel - brown coal, peat, shale, and also use natural gas. The efficiency of electric traction also increases when areas are powered by nuclear power plants.
Electric locomotives are more reliable in operation, require lower costs for equipment inspections and repairs, and can increase labor productivity by 16-17% compared to diesel traction.
Only electric traction has the ability to convert the mechanical energy stored in the train into electrical energy and transfer it during regenerative braking to the contact network for use by other electric locomotives or motor cars operating in traction mode during this period. In the absence of consumers, energy can be transferred to the power grid. Due to energy recovery, it is possible to obtain a large economic effect. Thus, in 1976, due to recovery, about 1.7 billion kWh of electricity was returned to the network. Regenerative braking improves the safety of trains and reduces wear on brake pads and wheel tires.
All this makes it possible to reduce the cost of transportation and make the process of transporting goods more efficient.
Due to the technical reconstruction of traction in railway transport, approximately 1.7 billion tons of fuel were saved, and operating costs decreased by 28 billion rubles. If we assume that until now steam locomotives would have been operating on our highways, then, for example, in 1974 it would have been necessary to consume a third of the coal mined in the country in their furnaces.
Electrification of Russian railways contributes to the progress of the national economy of the surrounding areas, since they receive power from traction substations industrial enterprises, collective farms, state farms and ineffective, uneconomical local diesel power plants are being closed. Every year, over 17 billion kWh of energy flows through traction substations to power non-traction consumers.
With electric traction, labor productivity increases. If with diesel traction labor productivity increases by 2.5 times compared to steam, then with electric traction it increases by 3 times. The cost of transportation on electrified lines is 10-15% lower than with diesel traction.
