RU2651382C2 - Method of power supply of traction network - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: group of inventions relates to power supply systems for electric traction networks. Method of power supply of an AC traction network is that the external power supply system transfers energy to a traction substation, energy input is monitored, converted and normalized to the type and voltage level required for the traction network and then distributed over the feeders of the traction network. External power supply system is made in the form of a pipeline system, through which energy is transferred in the form of fuel to a traction station. Energy of the fuel is converted into electrical energy by means of an engine and a generator, then the parameters are normalized by using a generator and a normalizing unit. Generators of traction substations are synchronized in phases. Voltage is normalized in magnitude by breaking this kind of normalization between the generator and the transformer included after the generator. Method of power supply of a DC traction network is proposed, in which the current type is normalized by the rectifier.

EFFECT: technical result of the inventions is reduction of energy losses and absence of the distortion of shape of the current consumed.

19 cl, 9 dwg

Description

The invention relates, in General, to power supply systems for traction networks of direct and alternating current.

State of the art

Known methods of power supply for electrified railways are that an external power supply system transfers energy to traction substations, converts energy at traction substations, then normalizes it to the type and level of voltage necessary for the traction network, then distributes electric energy to the feeders of the traction network [K. Marquardt G. "Power supply of electrified railways" Moscow, Transport, 1982, fig. 1.2 sec 10.], as well as [Bey Yu.M., Mamoshin P.P., Pupynin A.N., M.G. Shalimov "Traction substations." - M.: Transport, 1986. - Fig. 8 sec 16]. An external power supply system receives energy from large power plants.

Electrified railways in this method receive electricity from general-purpose networks and adversely affect energy quality indicators in these networks. These are distortions of the sinusoidal shape of the curved currents in traction networks of direct and alternating current, in addition, on railways electrified with alternating current, on the appearance of voltage asymmetry in the reverse sequence. This is because traction AC networks are single-phase, since the traction network is formed by a pair of wires: the contact network is a running rail, and general-purpose networks are three-phase. To reduce the asymmetry, the feeder zones to the left and to the right of the substation are fed from different phases of the traction transformer. This forces the inclusion of neutral inserts between the contact wires with different phases.

There are also significant energy losses in external distribution networks, due to the remoteness of the traction network from the powerful power plants of the power system.

A known method of power supply to the traction network [Vasilyansky AM, Mamoshin RR, Yakimov GB “Improving the traction power supply system of railways electrified with alternating current 27.5 kV, 50 Hz” Railways of the world, 2002, No. 8, p. 40-46]. In this method of power supply, the voltage of an external three-phase power line is converted into a single-phase voltage using a special balancing transformer and fed to an internal two-wire power line of increased voltage of 93.9 kV, from which traction substations supplying the traction network are supplied.

The disadvantage of this method is the presence of special high-voltage equipment of supporting substations with complex balancing transformers and a special switchgear, the need to use a special high-voltage single-phase two-wire line of 93.9 kV for direct power supply of traction substations and the absence of a source for supplying three-phase district non-traction consumers to traction substations.

A known method of energy supply [Burkov AT, Grishin Ya.S. "Converter device" RF patent 2206949]. In this method of power supply, the voltage of the primary external three-phase power line is converted into a single-phase voltage using special inverters and fed to a special high-voltage single-phase two-wire power line of 110 kV, from which traction networks can be powered.

In this method, there is no effect on the quality of electric energy in general-purpose networks, due to the use of inverters. The disadvantage of this method is the presence of high-voltage equipment, the need to use a special high-voltage single-phase two-wire line for direct power supply of traction substations, the absence of a source for supplying three-phase district non-traction consumers at traction substations.

A known method of power supply to the traction network [Marquardt, K.G. "Power supply of electrified railways" - Ed. 4th, rev. and add. - M.: Transport, 1982. - Fig. 1.5. from. eleven]. In this method of power supply, the voltage of the primary external three-phase power line is converted into single-phase voltage using special motor generators and fed to a special high-voltage two-wire power line 110 kV 16 2/3 Hz, from which traction substations supplying the traction network are supplied.

The disadvantage of this scheme is its complexity, namely, the construction of special converter (motor-generator) substations, and the need to use a special high-voltage single-phase two-wire line for direct power supply of traction substations, the lack of a source for powering three-phase district non-traction consumers at traction substations.

The last three methods are similar to each other, as they require a special high-voltage power line of the order of 110 kV.

Terms for ease of presentation

Further we will use the term traction station, summarizing the terms traction substation and traction power station, which supply or can supply electricity to the traction network. At the stations, any parameters of the energy or its type are converted, then it is distributed.

The term energy supply in the context of the description of the proposed method refers to the supply of any type of energy, including the supply of liquid or gaseous fuel used to produce energy in a form convenient for transformation and end use.

Prototype

Closest to the proposed one is a method of power supply to the traction network of electrified railways [Bei Yu.M., Mamoshin P.P., Pupynin AN, MG Shalimov "Traction substations." - M.: Transport, 1986. - Fig. 9 sec 17], adopted for the prototype.

In this method of power supply, an external power supply system transfers energy to the traction stations, the energy at the inlet of the traction station is controlled, then it is converted and normalized to the type and level of voltage necessary for the traction network, then it distributes electric energy to the feeders of the traction network.

An external power supply system is represented by a three-phase power line, with a voltage of 10, 20 or 35 kV, mainly for a direct current traction network, 110 or 220 kV, mainly for an alternating current traction network, from which traction substations are directly fed. The control consists in choosing an energy source, if there are several of them and the voltage value and type of current are converted at the traction stations (with a traction DC network, three-phase alternating current is converted to direct current, and with a traction AC network, three-phase current is converted into single-phase for a separate traction feeder network).

The prototype energy supply method has a common drawback of all its analogues - the remoteness of traction substations from power plants supplying general-purpose power systems, which causes large losses of energy and its cost. In the prototype, the shape of the current consumption is non-sinusoidal, which causes a deterioration in the quality of electricity in an external power supply system.

When traction stations for traction AC networks, the asymmetry of currents and voltages in the external power line is added to the disadvantages. Asymmetry also arises from energy recovery by a single-phase traction load returned to a three-phase network. It is not possible to return it to other traction loads on feeders with a different supply phase. To reduce asymmetry, energy conversions at traction stations are complicated, voltages from two different phases are supplied to the traction network, which complicates the design of traction networks. To separate the voltage of different phases on adjacent feeders, neutral inserts are used. Power supply to adjacent feeder zones is carried out from different phases to reduce asymmetry. This leads to the appearance in the traction network of longitudinal sectioning in the form of neutral inserts. In these places there may be interruptions in the supply of electricity to the rolling stock.

SUMMARY OF THE INVENTION

The aim of the invention is to eliminate the above disadvantages.

The object of the invention is a method for supplying power to traction networks, an external power supply system transfers energy to traction stations, the energy supply to the traction station is monitored, then it is converted and normalized to the type and level of voltage necessary for the traction network, then it distributes electric energy to the feeders of the traction network.

In accordance with the invention, the external power supply system is made in the form of a piping system through which energy is transmitted in the form of hydrocarbon fuel, mainly in the form of gas, at traction stations, the energy of hydrocarbon fuel is converted into electrical energy by means of an engine and a generator, power generation by generators of traction stations is carried out synchronized in phases, and not only within the framework of this traction station, but also with the voltage phases of the generators of neighboring traction stations, at least with one oh side. Further, energy conversions occur in two versions, determined by the type of traction network, but united by a general purpose.

For AC traction stations, the type of voltage is normalized by the number of phases by making the generator single-phase, by the magnitude of the voltage, this standardization is broken down between the generator and the autotransformer or transformer connected after the generator. For traction AC networks of the form 2 × 25 kV, voltage regulation by the number of phases is supplemented by transforming the generator voltage into two output voltages counter to each other using a transformer.

For a DC traction network, normalization of the type of voltage as a constant voltage is carried out by performing a generator multiphase, mainly three-phase, with the selection of the voltage of the generator windings according to the rules known for converter transformers and further converting the type of current in the respective converters, for example, rectifiers. The type of direct current according to the number of ripples is set by running a generator with the required number of windings and their connection schemes according to the rules known for converter transformers.

In the case of traction networks of increased direct voltage, for example 16 kV or more, the output voltage is normalized by selecting the value of the transformation coefficient of the step-up transformer or autotransformer, before normalizing the type of current.

In both variants of the method, the generators have combined functions, in addition to the main function - generating electric energy, have an additional function - normalizing the type of current and the voltage of the traction network.

To increase the reliability of power supply at the traction station, a stock of hydrocarbon raw materials is created, preferably in liquid form. In this case, the engines perform with switching modes of fuel use: gaseous or liquid.

In order to increase the efficiency of energy conversion contained in the incoming hydrocarbon fuel, the energy of high-temperature engine exhaust gases can be cogenerated at the traction station. Cogeneration energy is used to generate electricity using an additional generator or for heating residential villages or industrial premises located near the traction station.

The traction station must provide power to non-traction consumers. For this, power options are provided both from their generator, and using inverters. The specific implementation depends on the required power supply. The generator can receive mechanical energy from its engine or from the engine for traction. With a relatively small power of non-traction load, an inverter can be used. The inverter can be connected to an alternating current voltage as well as to direct current at stations for a direct current traction network. In the latter case, this can schematically simplify the inverter.

To remove peak power from the generator, a high-speed energy storage device can be used.

Brief Description of the Drawings

In FIG. 1 shows a primary pipeline network 1 supplying a traction station 2 with hydrocarbon fuel, supplying a traction network 3. The traction station contains an input distribution unit 4, which controls the input fuel flow, a conversion unit 5, an output distribution unit 6, which distributes electric energy to the feeders of the traction network 3. The structure of the construction of the traction station in all the drawings is the same.

In FIG. 2 on the left is the structure of the converter unit 4. It contains a motor 7, to the output shaft of which an electric generator is connected 8. A normalizing unit 9 is connected to the output of the generator. Its output is the output of the converter 5.

In FIG. 2, on the right, an embodiment of a traction station is presented, to which a reservoir 10 with a supply of hydrocarbon feedstock, mainly in liquid form, is added. In this case, the engine is performed with switching the type of input fuel: gaseous or liquid. A cogeneration unit 11 can be added, designed to use the energy of the hot exhaust gas from engine 7. In the example, a three-phase motor is installed at the output of the cogeneration unit to power its own stations and non-traction consumers.

In FIG. Figure 3 shows an embodiment of a traction station powered by non-traction consumers from a generator 12 connected to the output of the engine 7. This connection can be realized, for example, by connecting the shaft of the generator 12 to the shaft of the engine on the other side of the generator 8 or directly to the shaft of the generator 8. In these Examples, the energy transfer in mechanical form to the generator 12 comes from the engine 7. An additional element may be an energy storage device 13. In this drawing, it is connected to the output of the normalizing unit 9.

In FIG. 4 shows another example of obtaining power for non-traction consumers using an inverter 14. The inverter in the shown example receives energy from the output of the generator 8. Depending on the type of current in the traction network, if it is a direct current, the inverter can be connected to the output of the normalizing unit 9 .

In FIG. 5 shows an example of a normalizing unit 9 for a traction station supplying an alternating current traction network in the form of an autotransformer. It can be made in the form of a transformer.

In FIG. Figure 6 shows an example of a normalizing unit 9 for a traction station supplying an alternating current traction network made using a 2 × 25 kV system. In this case, the normalizing unit generates normal voltages for this system, which are 180 ° out of phase with respect to each other.

In FIG. 7 shows an example of a normalizing unit 9 for a traction station supplying a DC traction network. In this case, the normalizing block is, for example, a rectifier.

In FIG. 8 shows an example of a normalizing unit 9 for a traction station supplying a DC traction network with an increased voltage. Overvoltage refers to a voltage greater than 12 kV DC. In this case, the normalizing unit is a series-connected step-up autotransformer or transformer 15 and then a current type converter, for example a rectifier.

In the drawings, the letters “np” indicate the wire supplying non-traction consumers, the letters “p” indicate the wire that is connected to the rail, the letters “ks” indicate the wire that is connected to the contact network, the letter “p” indicates the wire that is connected to the supply wire of the 2 × system 25 kV.

In FIG. 9 shows an exemplary arrangement of traction station blocks. The input distribution block may be a gas distribution device, GRU. The conversion unit is based on a gas turbine unit - gas turbine unit and generator. The number of sets of a gas turbine generator can be several, depending on the power of the traction station and the required degree of redundancy, one or more. The output distribution unit 6 is a distribution device with a voltage of the traction network, as well as a distribution device with a voltage for non-traction consumers.

In FIG. 1-4, the top shows possible options for connecting the traction station to the primary pipeline network 1. In FIG. 1-2, the connection is made in the cut of the pipeline line, in FIG. 3 - connection without calling the pipeline to the traction station, in FIG. 5 - connection to two pipelines.

Description of preferred embodiments

The method is implemented as follows. The input switchgear 4 implements the function of selecting the input energy source, if there are several, and the choice of the engine-generator set connected to the energy. He can also disconnect this kit from an energy source, for example, for maintenance work. These types of actions are similar to the actions performed on the prototype.

Next, the energy is converted in block 5, which is enclosed in fuel, into thermal and mechanical energy, using the engine. Then, the generator converts mechanical energy into electrical energy.

Moreover, all generators at a given traction station, if their number is more than one, work synchronously with each other and synchronously with the generators of neighboring traction stations, at least on one side. This eliminates equalizing currents inside the traction station and significantly reduces the equalization currents between substations with parallel feeding of feeder zones from two traction stations. The generation of only a single-phase voltage for traction, while synchronizing the operation of the generators in phase, makes it unnecessary to use neutral inserts in the AC traction network. This eliminates unexpected stops of the rolling stock due to the presence of these neutral inserts, as in the prototype. In addition, their absence simplifies the traction network. On one side there can be a neutral insert, if this traction station is located at the end of the proposed power supply system and therefore borders on the prototype power supply system.

Another feature of the proposed method is the normalization of the voltage and type of current, in the form of the number of phases directly at the generator. In addition to the generation function, he has the function of partial normalization of electric current parameters both at the traction station for the traction AC network, and for the traction DC network. Both variants of the method are combined by a common concept.

For an AC traction station, the choice of a single-phase generator for train traction eliminates any problems with the asymmetry of currents and voltages for non-traction consumers. Especially for public networks, since there are no connections with them. This is especially important for areas where local power consumption is poorly developed and the traction load will be comparable to or greater than the regional loads.

It is customary to run generators at a voltage of not more than 10 kV, which is not enough to power a traction AC network of 27.5 kV, therefore, additional normalization by the voltage value is carried out using a step-up autotransformer or transformer.

At traction stations for both types of traction networks according to the proposed method, there is no electrical equipment with a voltage higher than the voltage of the traction network, which greatly simplifies its electrical part compared to the traction station of the prototype, which has a large number of equipment for voltage of 35, 110 or 220 kV. The installed capacity of the generator of the traction station for an alternating current network according to the proposed method is less than that of traction step-down transformers of similar traction stations according to the prototype, which are three-phase-two-phase. Both of these circumstances significantly compensate for the complication of the traction station according to the proposed method, caused by the presence of an engine. The single-phase generator as an electric machine according to the proposed method almost compensates for the complexity of the traction transformer according to the prototype as an electric machine due to the combination of functions and fewer windings.

For DC traction stations, phase synchronization of the generators is also important to eliminate equalizing currents in the harmonic components of the rectified voltage inside the substation and in the traction network. In addition to energy losses, the flow of these currents through the traction network worsens the electromagnetic compatibility of the traction network with other electrical objects.

The implementation of generators at traction stations for a traction DC network with the voltage required by the current type converters, namely the conversion of alternating current to direct current, eliminates the need for special step-down traction transformers, as in the prototype. The output voltage of the generator is related to the voltage of the rectifier by well-known formulas, so for a three-phase bridge rectifier it is connected to the rectified voltage by a coefficient of 0.427 [Sh.M. Razmadze, Conversion schemes and systems, p. 38. formula 1.13]. The generator acquires another function, in addition to generation, - the creation of an output voltage with a given number of phases and the necessary winding connection schemes, that is, it also performs the functions of a converter transformer.

These advantages of the proposed method make it possible to realize in a rather simple manner the advantages of replacing centralized power generation with distributed generation close to the place of electricity consumption. This eliminates significant energy losses during its transmission over long distances, since now the distance between the electric power generator and the traction feeder is meters or tens of meters, instead of hundreds of kilometers according to the prototype. The energy loss during transmission through gas pipelines is ten times less than the energy loss when using power lines.

Adding to the traction station a tank 10 with a fuel reserve increases the reliability of the traction station in the event of a gas outage. In the traction station of the prototype, it is fundamentally impossible to stock up on electricity, especially for a long time, a day or more.

The supply of this fuel is determined by the specified battery life of the traction power plant, according to the requirements of reliability of power supply to the traction network. For example, 3 hours or 3 days.

Another means of increasing reliability is the use of double-strand gas lines, gas lines with two-way power. For this, the connection of the traction station to the primary power supply system shown in the drawings is different.

To reduce the need for installed power of the equipment of the traction station, it is possible to connect an energy storage device 13 to the input of the output distribution block 6. This storage device smooths the peaks of energy consumption from the generator 8, which can last for units or tens of minutes.

To increase the efficiency of fuel use, energy cogeneration can be added, which consists in using the energy of the exhaust gases of a gas turbine engine, the temperature of which can reach 500 °. As an output of the cogeneration unit, a three-phase generator can be used to power non-traction loads. When consumers of thermal energy, industrial enterprises or residential settlements are located near the traction station, the energy from the cogeneration unit can be given in the form of heat. It is possible to use a three-phase inverter to provide power to non-traction consumers. At an AC traction station, energy can be obtained from a single-phase voltage after the generator to a step-up transformer to simplify the inverter. At a DC traction station, energy can be obtained after rectifiers to simplify the inverter. With a large capacity of non-traction consumers, it is advisable to power them from their engine-generator set.

Increasing the frequency of the generator at the traction station for a DC traction network greater than the industrial frequency, for example, up to 100 Hz, will reduce the overall dimensions of electrical machines and filter devices, this is important for traction stations with an increased voltage in the traction network. It will also reduce ripple in the traction network and increase electromagnetic compatibility.

Information sources

1. Marquardt K.G. "Power supply of electrified railways" Moscow, Transport, 1982, fig. 1.2 sec 10.

2. Bay Yu.M., Mamoshin P.P., Pupynin A.N., M.G. Shalimov "Traction substations." - M.: Transport, 1986. - Fig. 8 sec 16, fig. 9 sec 17.

3. Vasilyansky A. M., Mamoshin R. R., Yakimov G. B. “Improving the traction power supply system of railways electrified with alternating current 27.5 kV, 50 Hz” Railways of the world, 2002, No. 8, p. 40-46.

4. Burkov A.T., Grishin Ya.S. "Converter device" RF Patent 2206949.

5. Marquardt K.G. "Power supply of electrified railways" Moscow, Transport, 1982, fig. 1.5 sec eleven.

6. Marquardt K.G. "Power supply of electrified railways" Moscow, Transport, 1982, fig. 1.3 and Figure 1.4. from. 10.

7. Razmadze Sh.M. "Conversion schemes and systems", p. 38, formula 1.13.

Claims (19)

1. The method of power supply to the traction AC network, in which an external power supply system transfers energy to the traction station, the energy supply to the input of the traction station is controlled, then converted and normalized to the type and level of voltage necessary for the traction network, then distributes electric energy to the feeders of the traction network characterized in that the external power supply system is made in the form of a piping system through which energy is transmitted in the form of fuel, mainly in the form of hydrocarbon fuel, to traction at the output stations, hydrocarbon fuel energy is converted into electrical energy using an engine and generator, voltage regulation by the number of phases is carried out by single-phase generation of the traction station generator, traction station generators are synchronized in phases, not only within the framework of this traction station, but also with the voltage phases of neighboring generators traction stations, at least on the one hand, the regulation of voltage in magnitude is carried out by breaking this type of regulation between the generator and the autotransformer Whether transformer included after the generator. 2. The method according to p. 1, characterized in that for AC traction networks of the form 2 × 25 kV, voltage regulation by the number of phases is supplemented by transforming the generator voltage into two output voltages counter to each other using a transformer. 3. The method according to p. 1, characterized in that the traction station create a supply of hydrocarbon feedstock, preferably in liquid form. 4. The method according to p. 1 or PP. 3 and 6, characterized in that before converting the energy by means of an engine, the type of fuel source is controlled, and the engines are configured to operate on gaseous or liquid fuel. 5. The method according to p. 1, characterized in that it additionally carry out cogeneration of energy by using the energy of the exhaust hot gases of the engine to generate additional energy, for example, to power non-traction consumers. 6. The method according to p. 1, characterized in that the electricity received by the generators is inverted to supply non-traction loads. 7. The method according to p. 5, characterized in that the invertible energy is selected at a convenient for the inverter to operate voltage level and current form after the generator. 8. The method according to p. 1, characterized in that the obtained electrical energy is stored in the drive, made, for example, in the form of a capacitor and / or battery. 9. The method according to p. 7, characterized in that the energy is taken and given at convenient for the drive voltage levels and the form of current after the generator. 10. The method of power supply to the traction DC network, in which an external power supply system transfers energy to the traction station, the energy supply to the input of the traction station is controlled, then converted and normalized to the type and level of voltage necessary for the traction network, then distributes electric energy to the feeders of the traction network characterized in that the external power supply system is made in the form of a piping system through which energy is transmitted in the form of fuel, mainly in the form of hydrocarbon fuel, to rods at the output stations, hydrocarbon fuel energy is converted into electrical energy by means of an engine and generator; for traction networks, generation is carried out by performing a traction station generator by multiphase, preferably three-phase, normalization of the type of current is carried out by a converter with a function of converting the type of current, for example a rectifier, normalization of the magnitude of the output DC voltage selection of the output voltage of the generator according to the rules known for converter transformers . 11. The method according to p. 10, characterized in that the type of direct current according to the number of ripples is set by executing a generator with the required number of windings and their connection diagrams according to the rules known for converter transformers. 12. The method according to p. 10, characterized in that for traction networks of high DC voltage, the normalization of the magnitude of the output voltage is additionally produced by selecting the magnitude of the transformation coefficient of the step-up transformer or autotransformer. 13. The method according to p. 10, characterized in that the traction station create a supply of hydrocarbon feedstock, preferably in liquid form. 14. The method according to p. 10, characterized in that before converting the energy using the engine, the type of fuel source is controlled, and the engines are configured to operate on gaseous or liquid fuel. 15. The method according to p. 10, characterized in that it additionally carry out cogeneration of energy by using the energy of the exhaust hot gases of the engine to generate additional energy, for example, to power non-traction consumers. 16. The method according to p. 10, characterized in that the electricity received by the generators is inverted to supply non-traction loads. 17. The method according to p. 3, characterized in that the invertible energy is selected at a convenient for the inverter to operate voltage level and current form after the generator. 18. The method according to p. 10, characterized in that the received electrical energy is stored in the drive, made, for example, in the form of a capacitor and / or battery. 19. The method according to PP. 10 and 18, characterized in that the energy is taken away and given away at voltage levels convenient for the drive operation and the current type after the generator.

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