RU2703925C1 - Method of amplification of alternating current traction power supply system - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention relates to power supply for electric networks contacting with current collectors of vehicles. Method of AC traction power supply system amplification consists in the following. Voltage is supplied to the contact line using the AC voltage source. Voltage is supplied to additional line by means of additional line voltage source, at that energy from additional line to contact line is supplied through voltage converters of additional line. Additional line is arranged preferably on contact line supports. Voltage to the additional line is supplied in the form of constant voltage relative to the track circuit using a constant voltage source, and voltage converters of the additional line are made in the form of direct current to alternating current converters.

EFFECT: increase of current loads and increase of distance between traction substations.

10 cl, 4 dwg

Description

Technical field

The invention relates to the field of electrical engineering and can be used for newly electrified lines and amplification of electrified sections of AC railways.

The technical solution allows to increase the throughput of the electrified railway, as well as to increase the distance between the traction stations having primary power supply.

State of the art

Known methods of the traction power supply system of the network, in which additional energy is transferred to the line using additional lines laid along the line itself. In a simple case, these are reinforcing wires through which energy is transmitted under the same voltage as through the contact network. Increasing the cross section of AC lines to reduce the voltage drop is ineffective, due to the predominance of the inductive component in the impedance.

With more complex methods, a different voltage is applied to an additional line laid along the path. Additional energy helps to solve the above problems. A known method of amplifying the traction power supply system for alternating current is that the loads supplied from traction substations directly through the contact line are supplemented with energy received via an additional line in the form of a single-phase alternating current line having an increased voltage relative to the voltage in the contact line. An additional line transfers additional energy to the contact network through railways distributed along the line. converter points that lower the voltage to the voltage level in the contact line. It is implemented in two versions, close to each other in their basic properties. In one embodiment of the known method, a single-phase line of 94 kV is used (Mamoshin PP and Vasilyansky A.M. “Distributed power supply system for alternating current of a railway with three-phase balancing and single-phase transformers”, RF patent No. 2258994, 2003) [1], in another embodiment The known method uses a single-phase line of 110 kV (Burkov AT, Grishin Ya.S., Kuznetsov AV “Traction power supply system for alternating current”, utility model of the Russian Federation No. 2867, 2003) [2]. Both versions of this method, using a high-voltage auxiliary line and converter points connected to it, implement an internal distributed power system. Due to this, the voltage drop across the contact line is reduced, and also the distance between substations is increased, which is positive.

However, this improvement is limited by the fact that in this method both lines are AC lines with high inductance. In addition, the high voltage of the wires of the additional lines of 63.5 + 27.5 kV in [1] and 110 kV in [2] makes their maintenance difficult. Moreover, these variants of the methods require an additional line of free-standing supports for suspension.

There is a method of an alternating current power supply system in which DC traction substations are used (V. Kislyakov, V. P. Semenchuk, V. Andreev, “Scheme of transfer of electrified DC lines 3 kV to alternating current 25 kV” in the inter-university collection scientific works, issue 788, "Improving the efficiency and reliability of power supply devices" MIIT, 1988) [3]. In this method, the output of DC traction substations includes converters of energy from direct current to alternating current. External power supply is required to power the substations themselves. The method is designed to convert electrification from direct current to alternating current. To enhance the current electrification on alternating current, it is complex.

A known method of traction power supply system for an alternating current railway, in which a voltage is applied to a contact line using an alternating voltage source at a traction substation, an additional line is placed on the supports of a contact line, and voltage from an alternating voltage source of the same value is supplied to this additional line on the contact line, but in antiphase. This increases the voltage at which additional energy is transmitted through an additional line to the contact line. The auxiliary line converter is designed as an autotransformer and connected so that it reduces the voltage value of the additional energy transmitted from the additional line to the contact line to the voltage value of the contact line. In this method, the wires of all lines are insulated at 25 kV AC voltage relative to the supports. [Chernov Yu.A. "Power supply of the railways." Textbook allowance. - M .: Federal State Budgetary Institution Educational and Methodological Center for Education in Railway Transport, 2016. p. 127] [4].

The method according to its features is closest to the proposed method and is adopted as a prototype.

The disadvantages of the prototype

In this method, it is not sufficient to reduce the proportion of energy transmitted along the contact line, since both lines, the contact and the additional, have a significant inductive resistance. Hence, it is impossible to increase current loads and / or increase the distance between traction stations over 70-80 km. In addition, there is an increase in the distorting effect of traction single-phase current in the contact line and especially in the additional line, as it approaches the place of installation of the AC voltage source.

It is also difficult to increase the number of loads in traction mode that could absorb the energy of the recovery load. Not enough effectively use an increase in the cross section of the wire of the additional line.

SUMMARY OF THE INVENTION

In order to eliminate the disadvantages of the prototype in the known method of a traction power supply system of alternating current, in which using an alternating voltage source voltage is supplied to the contact line, and also voltage is supplied to the additional line using an additional line voltage source, energy from the additional line to the contact line is supplied through voltage converters of the additional line, place the additional line, preferably on the supports of the contact line, and the voltage on the additional the line is supplied in the form of a constant voltage relative to the rail circuit, using a newly introduced constant voltage source, the voltage converters of the additional line are in the form of a DC to AC converter.

The constant voltage of the auxiliary line is performed with a larger value than the effective value of the alternating voltage of the contact line.

The voltage converters of the auxiliary line are capable of inverting power from the contact line to the auxiliary line.

In the double-track execution of the railway, one additional line feeds the contact lines of one and the other paths or perform two additional lines of the one and the other paths, which feed their contact lines with the help of one constant voltage source.

In addition, when completing additional lines separately for each path, a constant voltage of the same sign is applied to an additional line of another path as the alternating line of one path, or a constant voltage source is bipolar, and then a constant voltage of the opposite sign is supplied to an additional line of another path , with respect to the additional line of one path.

The voltage converters of an additional line with two additional lines receive input power from their additional line and rail circuit, or they receive input power from both additional lines when the voltage on them is of the opposite sign.

The additional line wire is made in the form of an insulated self-supporting wire, which may have a modification in the form of an electro-optical wire.

The energy store is connected either between the rail circuit and the contact line, or between the rail circuit and the additional line, or between additional lines.

The implementation of all sources supplying contact lines extending in different directions, with one phasing, allows contact lines for traction stations without neutral inserts.

You can use a shielding wire, preferably its implementation in the initial part of the power supply system, counting from the installation site of AC and DC voltage sources, and it is also preferably performed in the form of a self-supporting insulated wire.

It is possible to carry out an additional line in its initial part of the power supply system, counting from the installation site of AC and DC voltage sources, with a larger cross section than in the remaining part of the additional line.

From the scientific, technical and patent literature, this method is unknown, therefore, the inventive method has novelty and significant differences.

Brief Description of the Drawings

In FIG. 1 shows a diagram of a traction power supply system for a single-track AC railway section using a traction network of 25 + 35 kV.

1 - traction station;

2 - source of alternating voltage for the contact line;

3 - rail chain;

4 - contact line of one path;

5 - electric rolling stock;

6 - a constant voltage source for an additional line;

7 - an additional line of one path;

8 - voltage converter auxiliary line.

In FIG. Figure 2 shows a diagram of the traction power supply system of a two-track AC railway section using a traction network of 25 + 35 kV and one additional line.

9 - contact line of another path.

In FIG. Figure 3 shows a diagram of a traction power supply system for a two-track AC railway section using a traction network of 25 ± 35 kV, with separate additional lines of one and the other paths, in the variant of bipolar voltage execution of additional lines relative to the rail circuit, with a bipolar DC voltage source and additional voltage converters lines with increased input voltage. An example of connecting an energy storage device is also shown there.

10 - additional line of another path;

11 - bipolar source of constant voltage;

12 - voltage converter auxiliary line with high input voltage;

13 - energy storage.

In FIG. Figure 4 shows the curves characterizing the voltage for various power systems.

14 - voltage curve with a two-track system 2 × 25 kV;

15 - voltage curve with a two-track system 25 + 35 kV;

16 - voltage curve with a two-track system 25+ (± 35) kV.

Description of preferred embodiments

In a diagram of an exemplary embodiment of traction power supply according to the method of FIG. 1, for a single-track railway section, there is a traction station 1, an alternating voltage source 2 for the contact line, for example with an output voltage of 25 kV, connected by one output to the rail circuit 3 and the other output to the contact line 4. Traction load, in the form electric rolling stock 5, receives power from the contact line 4 and the rail circuit 3. Also at the traction station 1 there is a constant voltage source 6, connected by its positive output to the additional line 7, its negative output connect ny to the track circuit 3.

For the operation of the traction power supply system, the features of the implementation of alternating and constant voltage sources do not matter. For example, the implementation of an alternating current source in the form of transformers or in the form of a three-phase converter into a single-phase voltage, using power electronics powered from a primary public network, in the case of a traction substation. In the case of using a traction power plant, the AC voltage source will be a single-phase generator, with a transformer or autotransformer, to normalize the output voltage to a standard value in the contact line. Constant voltage at a traction power plant can be obtained from a valve generator. Therefore, in the claims, traction substation or traction power plant as objects are not present, and only their essential parts are important, in the form of voltage sources. Traction power plants are known (Benyash Yu.L. “Method of power supply to the traction network”, RF patent No. 2651382, op. 19.04.2018) [5]. Further in the description, traction substations and traction power plants are combined by the term traction stations.

Inside the traction power supply system between traction stations 1, a separate distributed power subsystem appears, consisting of traction mini-stations, with the main equipment in the form of voltage converters 8 of an additional line, similar to prototype mini-stations with converters in the form of autotransformers. Inside the minibands formed by the mini-stations, the current distribution between the contact line and the rail circuit corresponds to the current distribution in a conventional AC power supply system. The electric rolling stock receives power from two sides along the contact line and gives current along the rail circuit in both directions to the mini-stations.

In the prototype, additional energy is supplied through an additional line 7 under an alternating voltage of 50 kV relative to the contact line 4. As a result of the complex electromagnetic interaction of both of the above lines and the double voltage in the additional line relative to the contact line, two fractions of power are transmitted along the additional line, relative to transmitted power on the contact line, taken as one share. The decrease in power and current in the contact line 4 leads to a decrease in the voltage drop in it. which gave this traction power supply system an advantage over a conventional power supply system.

Another embodiment of the converters in the invention changes the ratio of the shares of the transmitted capacities of the electric rolling stock transmitted along the contact and additional lines outside the minibands. For an additional line, its resistance to direct current must be taken into account, and for a contact line, its resistance to alternating current. To assess the effect of the invention, take, as an example of calculation, an additional line with a wire A-185, often used for these lines. Its resistance to direct current, taking into account the cross section of the wire 185 mm ² and the material of the wire - aluminum, is r = 0.17 Ohm / km. The resistance of the contact line according to the invention can be taken equal to the resistance of a conventional contact line of 25 kV. This resistance, according to (Figurnov EP “Relay protection.” Textbook. At 2 h. Part 2. “Relay protection of traction power supply devices for railways.” M .: 2009. p. 28-31) [6 ] can be taken on average about 0.4 ohm / km.

We initially accept a constant voltage in an additional line 7 of 25 kV. Then the shares of the prototype of the energy transfer along the contact line and the additional line and the energy transfer share of the invention will be approximately the same, namely 1 to 2. In favor of the prototype is the transfer of part of the energy to the load under voltage of 50 kV in the additional line relative to the contact line. The increase in voltage in the additional line according to the invention to a value of 25 kV⋅√2 = 35.3 kV, to the level of the voltage amplitude in the contact line, increases its share in (√2) ² = 2 times, and the ratio of the fractions will be already 1 to 4 The method according to the invention obtains an advantage in the distribution of currents after increasing the voltage value in the supply line from a value exceeding the value of the effective value of the alternating current in the contact line.

Converting the current in the additional line from alternating to direct current eliminates the appearance of adverse changes in the shape of the current consumed by the load in the additional line and the accumulation of these changes with an increase in the number of loads. Increasing the cross section of the wire of the additional line will give the effect of reducing its resistance more than in the method of the prototype, which will make it efficient to use the reinforcing wire for the additional line, especially at its beginning.

At a voltage of 35 kV DC, the insulation of the additional line will correspond to the insulation of the additional line according to the prototype, since the voltage in the additional line according to the prototype, being in antiphase relative to the contact line, has only 25 kV AC relative to the support.

Reducing the proportion of current in the contact line reduces the magnitude of the voltage drop in it, this allows you to increase current loads and / or to increase the distance between the traction stations.

The introduction of a shielding wire will give a noticeable effect at the beginning of the traction power supply lines, counting from the place of installation of voltage sources, that is, from traction stations, since there will be the highest currents in both lines.

Additionally, the conversion of current from AC to DC eliminates the adverse effects of various distortions in the shape of the AC load, improving electromagnetic compatibility.

Additional lines are preferably, as in the prototype, placed on the supports of the contact line, to simplify the design. The preference for placing an additional line on the supports of the contact network simplifies the design of this line. The placement of additional lines on separate supports is permissible, since this does not affect the presence of the main effect of the invention — a decrease in the current in the contact line and the associated voltage drop in the contact line.

The voltage Converter 8 can be made in the form of a stand-alone inverter, with the synchronization of the output voltage with the voltage in the traction network. The output of the voltage converter of the auxiliary line 8 connected to the rail circuit 4 acts as an input for direct voltage and an output for alternating voltage.

The diagram of the traction power supply system of FIG. 2 is made for a double-track railway. It differs from the circuit of FIG. 1 by the appearance of the contact line of the other path 9. The voltage converters of the additional line 8 supply voltage to one and the other contact lines, receiving their power from one additional line.

In FIG. 3 shows another embodiment of a traction power supply system for a double-track railway. In it, voltage converters of additional lines 8 receive input voltage from one 7 and another 10 additional lines, respectively, to their paths, one and the other way. This makes it possible in principle to reserve additional lines and reduce the current load with respect to the embodiment of the traction power supply system of FIG. 2.

In addition, in FIG. Figure 3 shows a variant of the traction power supply system for a double-track railway section, in which the opposite line voltage is applied to an additional line 10 of a different path than to an additional line 7 of the same way and the direct current source 11 is installed on the traction station 1 with bipolar outputs. Moreover, the voltage converter 12 of the additional line is connected with its DC voltage inputs between both additional lines 7 and 10, the sum of their voltages. In the illustrated embodiment, respectively, with the circuit of FIG. 1, the input voltage to the auxiliary line converter will be 35 kV + 35 kV = 70 kV DC. In this way, the converter of the additional line 11 differs from the converter of the additional line 8. This connection significantly increases the energy possibilities of transferring additional energy to the loads 6 through the converters of the additional line 11, reducing the equivalent resistance of the traction network, depending on the square of the voltage ratio. The insulation level of additional lines 7 and 10 relative to the supports remain at the level of constant voltage of 35 kV.

The traction power supply system according to this embodiment can be characterized by the designation 25 ± 35 kV.

With a two-way power supply system, the use of bipolar voltage on additional lines relative to the rail circuit leads to the fact that the currents in the rail circuit will be directed opposite each other and cancel each other out. Full compensation occurs when the voltage converters of the auxiliary line are supplied with the same absolute value of bipolar voltage in the auxiliary lines. In this case, stray currents from the DC component in the rail circuit will be nullified. Given this effect and the double increase in voltage of the voltage converters described above, bipolar extension lines will be preferred.

The implementation of an additional wire in the form of a self-supporting insulated wire (Larin Yu.T., Pronin GI, Fomichev V.Yu. “Combined electro-optical self-supporting insulated wire.” PM No. 80278) [8] facilitates the execution of its suspended insulators and prevents the appearance of a short faults, for example, when trees fall on them. Insulation of the additional line wire improves the service conditions of this and contact lines. The implementation of this wire combined with an electro-optical core allows you to enter information channels for telemechanics and relay protection of a linear power point, the main element of which is an additional line voltage converter.

In FIG. 3 also shows the possible connection of energy storage 12 to the voltage of the contact lines. Energy storage 12 allows you to remove peak currents from the contact and additional lines at close starts of loads 6. This improves the voltage mode on the contact line at starts of loads 6. Energy storage for a short time, during start-ups, reduces the resistance of the traction power supply system.

The implementation of all AC voltage sources at traction stations and additional line voltage converters installed on the line with the same phasing of their AC output voltage will allow the contact network to be made without neutral inserts, as in the analogs of [1], [2].

Reducing the equivalent resistance of the traction network and the possibility of inverting the current by the converter of the additional line allows you to transfer the energy of the recovery load to other, remote loads in traction mode, which increases the number of consumers.

The transfer of most of the energy to trains through an additional direct current line reduces the magnitude of the alternating current in the contact line, which, in turn, reduces the alternating component of the magnetic field. This helps to reduce the inductive effect of the AC railway on adjacent communication lines and power lines. To further reduce the electromagnetic effect of the alternating current of the contact line, a shielding wire can be used at the beginning of the section where there will be the greatest current in the contact line.

To reduce the voltage drop in the auxiliary line, its implementation with a large cross section is effective, especially in the initial part, counting from the DC voltage source to the first voltage converter of the auxiliary line. A multistage increase in the cross-section of the additional line is also possible, approaching a source of constant voltage. In the prototype, such an increase in the cross section practically does not reduce the voltage drop in the additional line, since in the prototype the inductive resistance of this line prevails over the active resistance.

Energy storage devices perform a well-known function - removing short-term peak loads, for example, when rolling stock starts, which improves the voltage mode in the contact line.

With a phased traction power supply system, the subsequent transition from an alternating voltage in the contact line to an increased direct voltage is facilitated, since constant voltage sources are already available at traction stations and it is not necessary to change the insulation of both lines.

The figure 3 shows examples of voltages in the contact line and allowing to give a qualitative assessment. The voltage level according to the prototype is shown by curve 14, curve 15 - when the voltage level in the additional line is 35 kV and curve 16 - when the bipolar voltage in the additional lines is ± 35 kV and the voltage converters of the additional line are connected to it. The highest voltage level in the latter case.

List of sources used:

1. Burkov A.T., Grishin Ya.S., Kuznetsov A.V. "AC traction power supply system", a description of a utility model for RF patent No. 2867, decl. 02/08/2002, op. 04/10/2003 g;

2. Mamoshin P.P., Vasilyansky A.M. "The system of distributed AC power supply of a railway with three-phase balancing and single-phase transformers", RF patent No. 2258994, declared December 20, 2001

3. Kislyakov V.A., Semenchuk V.P. Andreev VV, “Scheme for the transfer of electrified DC lines 3 kV to alternating current 25 kV” in the inter-university collection of scientific papers, vol. 788, "Improving the efficiency and reliability of power supply devices" MIIT, 1988

4. Chernov Yu.A. "Power supply of the railways." Textbook Allowance. - M .: Federal State Budgetary Institution Educational and Methodological Center for Education in Railway Transport, 2016. p. 127;

5. Benyash Yu.L. "The method of power supply to the traction network", RF patent No. 2651382, op. 04/19/2018

6. Figurnov EP "Relay protection". Textbook. In 2 hours, Part 2. “Relay protection of traction power supply devices for railways”. M .: 2009.p. 28-31.

7. Larin Yu.T., Pronin G.I., Fomichev V.Yu. "Combined electro-optical self-supporting insulated wire." PM No. 80278, op. 2009 year

Claims (10)

1. A method of amplifying an alternating current traction power supply system in which voltage is supplied to a contact line using an alternating voltage source, and voltage is supplied to an additional line using an additional line voltage source, energy from the additional line is supplied to the contact line via voltage converters of the additional line place an additional line, preferably on the supports of the contact line, characterized in that the voltage on the additional line is supplied in the form of a constant about the voltage relative to the rail circuit using a constant voltage source, voltage converters additional lines perform in the form of converters of direct current to alternating current. 2. The method of amplifying the traction power supply system according to claim 1, characterized in that the constant voltage of the auxiliary line is performed with a greater value than the effective value of the alternating voltage of the contact line. 3. The method of amplification of the traction power supply system according to claims. 1 and 2, characterized in that the voltage converters of the additional line are configured to invert energy from the contact line to the additional line. 4. The method of amplification of the traction power supply system according to claims. 1 and 2, characterized in that in the double-track design, one additional line feeds the contact lines of one and the other paths or perform two additional lines, one and the other paths that feed the contact lines of their path. 5. The method of amplification of the traction power supply system according to claims. 1 and 3, characterized in that when two additional lines are made, a constant voltage of the same sign is applied to the additional line of the other path as the additional line of one path, or a constant voltage of the opposite sign is applied to the additional line of the other path with respect to the additional line of one paths when performing a constant voltage source bipolar. 6. The method of amplification of the traction power supply system according to claims. 1, 3 or PP. 1, 3 and 4, characterized in that the input voltage to the voltage converters of the additional line is supplied from the additional line and the rail circuit or the input voltage to the voltage converters of the additional line is supplied from both additional lines with voltages of the opposite sign. 7. The method of amplification of the traction power supply system according to claims. 1-4, characterized in that the additional line wire is made in the form of an insulated self-supporting wire, which may have a modification in the form of an electro-optical wire. 8. A method of amplifying the traction power supply system according to claim 1, characterized in that the energy storage device is connected either between the rail circuit and the contact line, or between the rail circuit and the additional line, or between additional lines. 9. The method of amplification of the traction power supply system according to claims. 1-4, characterized in that the AC voltage sources supply the contact lines extending in different directions with one phasing. 10. The method of amplification of the traction power supply system according to claim 1, characterized in that it is installed in the initial part of the traction power supply system, counting from the place of installation of AC and DC voltage sources, a shielding line and / or an additional wire to the additional line, increasing the cross section of the latter, preferably their implementation in the form of self-supporting insulated wires.

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