JP2010011711A - Microgrid using electric railroad system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an economically viable microgrid using an electric railroad system effectively, on the basis of the priority of applying to the microgrid essentially possessed by the electric railroad system. <P>SOLUTION: The electric railroad system D includes a power supply equipment of the electric railroad containing a substation for the electric railway and a feeder wire 5. The feeder wire 5 is used as a transmission line (self-management line and distributed line) of the microgrid 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a microgrid constructed by effectively using power supply equipment in an electric railway system.

  In recent years, a plurality of distributed power sources and power storage systems distributed in a relatively small demand area are combined to supply consumers who need the power generated by the distributed power sources. Micro grids, which are small-scale power supply networks that enable local supply and demand, are drawing attention.

  However, among the distributed power sources of microgrids, for example, solar power generators (solar cells) and wind power generators that use natural energy are difficult to adjust the power generation amount and power generation timing, and it is difficult to keep up with fluctuations in demand. is there. In addition, a combustion generator using a prime mover such as a gas turbine, a steam turbine, or a diesel engine can adjust the power generation timing, but if operated according to demand, it cannot be operated in a highly efficient state. In addition, natural energy such as sunlight and wind power is affected by the natural environment, day and night, and season, resulting in fluctuations in the amount of power generation, making it difficult to balance power supply and demand. Fluctuating easily, power quality is inferior, and may adversely affect electrical equipment. Furthermore, in these microgrids, it is necessary to newly lay transmission lines that connect between consumers in a demand area or between a distributed power source and consumers.

  For example, the power generation efficiency of a combustion generator using a prime mover in a distributed power source as described above cannot be said to be high, and a power generation facility that uses natural energy, such as a solar cell or a wind power generator, generates power. The quality of electricity is not good. Furthermore, even if these power generation facilities are incorporated in the microgrid, it is not always advantageous compared to the commercial power system when a new transmission line needs to be installed.

  Therefore, the inventors paid attention to the electric railway system. In other words, in the electric railway system, many electric railway vehicles (hereinafter simply referred to as trains) run on the track, and some of those trains are accelerating (powering), while others are decelerating. (Braking), some other trains are traveling (coasting) at a constant speed, and some trains are stopped at a station or the like. Therefore, electrical energy can be converted into kinetic energy and stored when the train accelerates, and kinetic energy can be recovered and recovered by regenerative braking when the train decelerates. At the same time, it can be said that it is a power supply system with a power storage function called a train. The train acceleration time of a single train is usually very short, around 30 seconds, and because of the fact that the train travels on the track, the railway has a lower frictional resistance than a car that runs on rubber tires, so the distance that can be traveled by inertia is extremely high. Long. On the other hand, there are many opportunities for decelerating before stopping at a station or before driving on a curve, and as shown in FIG. 3, the load (power consumption) and power generation (power recovery) take a short time (eg, several seconds to several tens of seconds). ) In the form of pulses. Further, as confirmed from the graph showing the voltage displacement in the figure, the voltage change is ± 20%, which is larger than the voltage allowable range ± 10% of the commercial power system. In this way, the power supply situation in the electric railway system is such that the load and power generation are repeatedly performed in a pulsed manner, and the electric railway system is established despite the fact that the fluctuations in the load and power generation are larger than those in the commercial power system. In addition, it has a characteristic that the allowable range of voltage change is as wide as ± 20%.

  Furthermore, in the electric railway system, the electric power supplied from the commercial power system is received from the electric railway substation and supplied to the train through the feeder line, the third rail, etc. via the feeder. In addition, feeders are often already laid along train tracks (tracks) in electric railway systems, and transmission lines (distribution lines / self-operated lines) are re-established when constructing a microgrid power grid. There is no need to lay.

  On the other hand, in the commercial power system B, as shown in FIG. 4, the peak of power demand is around 2 o'clock in the afternoon, whereas in the electric railway system D, the peak of power demand is early in the morning (around 7 to 9 am ) And evening (around 5-8 pm), the peak of power demand is largely shifted in time, and it can be said that the power demand relationship between the two is complementary.

By the way, as a prior art related to a microgrid, a detection is performed by connecting a secondary battery having a large capacity and a high output to a power supply line via a charging / discharging device, and detecting the state of the load or the state of the power supply line and the state of the secondary battery. And a control device for controlling the charging / discharging device and the power supply device based on the power supply status detected by the detection device and the state of the secondary battery, and when the power surplus is estimated in the power supply line, the secondary battery There has been proposed a battery that is charged and discharged from a secondary battery when power shortage is estimated (see, for example, Patent Document 1).
JP 2007-159225 A

  The microgrid according to the above-mentioned Patent Document 1 intends to provide a microgrid that uses a large-capacity secondary battery to increase the power demand capacity of the power supply device and is also economically established.

  In terms of providing an economically viable microgrid, the problem to be solved is the same as that described in Patent Document 1, but the present invention provides a feeder that is originally provided in the electric railway system described above. Focusing on the advantage of using as a microgrid, we intend to provide a microgrid that is economically feasible and that effectively uses an electric railway system. In other words, the present invention differs from the microgrid described in Patent Document 1 in some means, but with specific solution means and problems.

  In order to achieve the above object, a microgrid according to the present invention is an electric railway system including an electric railway power supply facility including an electric railway substation and an electric railway. It is characterized by being used as an electric wire.

  According to the microgrid using the electric railway system of the present invention having the above-described configuration, the electric railway system is already installed to supply electric power necessary for running the train via an overhead line or a third rail. Since the used electric wire is used as a microgrid power transmission line (private line / distribution line), it is almost unnecessary to install a power transmission line. In an electric power system including a microgrid, the cost required for laying a transmission line is higher than the power generation equipment and the like, and the ratio of equipment costs is high, and the use of existing feeders saves a great deal of cost.

  In addition, the microgrid according to the present invention has a feeder as an essential component, and in addition to a train that operates on a track, it includes a station building and the like, and is related to supply and consumption of electric power in an electric railway system. All equipment and facilities are targeted. For example, not only drive motors, electric brakes, air conditioners, and lighting equipment equipped on trains, but also facilities such as lighting equipment, elevators, and air conditioners installed in station buildings are targeted.

  As described in claim 2, in the microgrid using the electric railway system according to claim 1, it is preferable to connect a secondary battery to the feeder.

  In this way, it is possible to achieve a balance between power demand and supply. In other words, when an excess or deficiency occurs between the demand and supply of power in the microgrid, the insufficient power is supplied from the secondary battery, while the generated surplus power is stored in the secondary battery. Thus, the time lag (unbalance) between power supply and demand can be leveled by the secondary battery to balance the two. In addition, it is possible to reduce the cost of electricity bills by suppressing the power supplied from the commercial power system at the peak of power consumption in the electric railway system. The contracted electricity charge of the commercial power system depends on the amount of contracted electricity separately from the total amount of power used, so the electricity charge can be significantly reduced by suppressing the peak power amount with the power supplied from the secondary battery. Because. In addition, if power generation equipment that uses natural energy, such as solar power generation and small hydropower generation, that affects the output during power generation, is connected to the microgrid, the generated power may exceed the load power consumption. The secondary battery can be charged with surplus power generated in the For example, in wind power generation, the amount of generated power and frequency are not controlled by the wind speed, and the generated power can be charged to the secondary battery by controlling the wind speed to always be the maximum output, so that the natural energy is maximized. Available to the limit. In addition, surplus power resulting from the load, for example, in a driving device such as an elevator, robot, crane, etc., when braking using a brake using a generator, etc., it is converted into electric energy as regenerative power, and converted into a secondary battery. By charging, kinetic energy and potential energy can always be collected and stored. Furthermore, when the train is decelerating, the power generated in electromagnetic braking is conventionally changed to heat with a resistor and discarded, but this power is stored in the secondary battery via the feeder and collected as electrical energy. You can also.

  Incidentally, when the microgrid according to the present invention is an AC power system, it goes without saying that the microgrid is connected to a secondary battery via an AC / DC converter. In addition, when the microgrid according to the present invention is a DC power system, a power generation facility using natural energy or a facility that generates AC power in a private power generation facility connects an inverse converter (so-called inverter) to the microgrid. There is a need. In other words, there are AC feeding and DC feeding in the feeding system.

  As described in claim 3, in the microgrid using the electric railway system according to claim 2, a nickel metal hydride battery can be used as the secondary battery.

  In this way, the nickel-metal hydride battery has a small internal resistance and a small voltage fluctuation with respect to the change in SOC (State Of Charge) (see FIG. 5), so that the electric capacity of the battery can be used effectively. Batteries with smaller dimensions can be used compared to other secondary batteries such as lead-acid batteries, nickel-cadmium batteries, NAS (sodium-sulfur) batteries, and nickel-metal hydride batteries have a high volumetric energy density. It's narrow. Moreover, since it is not necessary to interpose an expensive charge / discharge control device, the installation location of the charge / discharge control device is not necessary, and the equipment cost can be reduced. Moreover, the nickel metal hydride battery has no rapid operation like a step-up / down chopper and is excellent in rapid charge / discharge characteristics. In addition, since the nickel-metal hydride battery has a low internal resistance as described above, it is necessary to supply a large current instantaneously, particularly when the train accelerates, and even when the nickel-metal hydride battery discharges and responds, the loss is small. The voltage drop can be suppressed. Conversely, when the train decelerates, using a regenerative brake that uses a generator to brake the electrical energy as regenerative power, etc. It is possible to cope with it, and the rise of the wire voltage can be suppressed. Therefore, if a nickel metal hydride battery is used as the secondary battery, the feeder voltage can be stabilized and the operation of electric railway vehicles such as trains can be made more efficient.

  As described in claim 4, in the microgrid according to any one of claims 1 to 3, a power generation facility using natural energy can be connected to the feeder. Here, examples of the power generation facility using natural energy include a solar power generation device (solar cell), a wind power generation device, and a small hydropower generation device, but are not limited to these, and other distributed power sources are used. There may be. In addition, this type of power generation equipment is affected by the amount and frequency of power generation in the natural environment, and the quality of the power is generally inferior. As a result, the facilities are bulky as a whole. However, the power supply equipment in the electric railway system has an allowable range of voltage fluctuation of about ± 20%, which is larger than that of the commercial power system (about 10%), and the electric railway system itself can store electric energy. There is a possible system, and even though there is a steep current fluctuation due to repeated powering (acceleration) and regeneration (deceleration) of the train, it is operated without any problems even though it always has a large disturbance in terms of power. ing. Furthermore, in the commercial power system, harmonics are strictly defined in the guidelines, but there are no guidelines on such harmonics in the electric railway system. Therefore, according to the microgrid using the electric railway system according to claim 4, since the range (allowable range) in which poor quality power can be accepted compared to the commercial power system is wide, the power generation facility using natural energy generates power. The generated power can also be fully and effectively utilized.

  As described in claim 5, in the microgrid according to any one of claims 1 to 4, a private power generation facility can be connected to the feeder. Here, the private power generation facility may be a private power generation facility provided in a station building or an emergency private power generation facility. In addition, in the demand area of the microgrid, it may be a private power generation facility or an emergency private power generation facility of a factory located near the feeder line, or in a hospital or construction site located in the demand area and near the power line. It may be a private power generation facility or an emergency private power generation facility. Furthermore, examples of the prime mover used in the private power generation facility include a diesel engine, a gas engine, a gas turbine, and a steam turbine, but are not limited thereto, and may be a fuel cell, for example.

  According to the fifth aspect of the present invention, the above various prime movers can be operated under the most efficient conditions. In general private power generation, the prime mover cannot be operated at maximum efficiency in order to generate necessary power, but in the microgrid according to this claim, surplus power is electric energy in the electric railway system, Since energy can be stored in the state of kinetic energy, potential energy, magnetic energy, etc., the prime mover can always be operated at the maximum efficiency to save energy as a whole. In addition, when power is insufficient at a factory in the demand area, for example, surplus power can be supplied to the factory through a feeder that is a power network, so that power demand is highly flexible.

  As described in claim 6, the feeder can be connected to a commercial power system via a power trading instrument.

  If it does in this way, when supplying electric power from a microgrid to a commercial power system, the amount of electric power reversely sent can be measured, and surplus electric power can be collected as an electric power charge.

  As described in claim 7, it is desirable to provide the electric railway vehicle with a regenerative brake that is operated when the electric railway vehicle is decelerated.

  In this way, when the electric railway vehicle decelerates, the kinetic energy held by the vehicle can be recovered in the form of electric power as electric energy without being discarded by converting it into thermal energy, etc. If the railway vehicle is running, the regenerative power can be supplied to other electric railway vehicles via feeders or overhead lines, and if there are no nearby electric railway vehicles that need to be fed, feeders Energy can be saved by supplying regenerative power to the feeder, such as charging the secondary battery via a cable or overhead wire.

  According to the eighth aspect, an elevator, a crane, and other devices that generate potential energy can be provided with means for converting the potential energy into regenerative power.

  If it does in this way, the potential energy at the time of the elevator currently installed in a station building descend | falls can be converted into regenerative electric power, and can be collect | recovered.

  According to the ninth aspect of the present invention, means for converting magnetic energy into regenerative power can be provided in an electric motor, an electromagnet, a transformer, and other devices that generate magnetic energy.

  If it does in this way, the magnetic energy which an electric motor and a transformer have can be converted into regenerative electric power, and can be collected.

  The microgrid according to the present invention has the following excellent effects by using the electric railway system.

  1) There are many areas where trains run, mainly in major cities and their suburbs, which is consistent with microgrid demand areas. That is, according to the present invention, the microgrid as a means for supplying surplus power that is not used to consumers who need the power is naturally installed in the vicinity of the consumers, so that power is flexible. In addition, since the distance between the power generation source and the customers is very close, transmission loss can be minimized. In this way, by making power interchangeable, energy is saved as a whole, the amount of generated carbon dioxide is reduced, and this leads to environmental measures.

  2) In the microgrid, it is necessary to install a transmission line that connects the distributed power source such as solar cells and wind power generators to consumers. This installation requires a large amount of money, and it is necessary to maintain the transmission lines after installation. However, according to the present invention, it is possible to reduce enormous costs such as laying transmission lines and maintenance after laying. In addition, the feeder used as a power transmission line in the microgrid of the present invention usually has characteristics suitable for train operation, and a hard steel stranded wire or a hard aluminum stranded wire with low electrical resistance is used. And since it is fully insulated from the periphery, the quality as a power transmission line is extremely high. Also, feeders are perfect as a microgrid power network because they are stretched around the demand area along the track of the electric railway system. Furthermore, when installing a facility such as a distributed power supply device in a factory or the like away from the track, it is only necessary to install a power transmission line connecting between the facility and the electric wire, which is also advantageous in this respect.

  3) In general, commercial power grids often transmit power from power stations installed at locations away from power demand areas over long distances.

  In contrast, private trains that run on the ground, public subways, and streetcars that include LRVs (low-floor road vehicles) pass through areas in the city and its suburbs, where so-called electricity demand is high. In many cases, feeders of an electric railway system are provided along the trajectory, so that they are optimal as transmission lines for microgrids and have less transmission loss than using transmission lines of a commercial power system.

  4) In electric railway systems, the main electric power supply from the commercial power system has been provided to provide transportation services. The electric railway system itself is an economically established system in which trains traveling on the track store electric power. It has a function (for example, a running train is used as kinetic energy), and so far, kinetic energy (or potential energy) generated when braking is applied, for example, when the train is decelerating has not been recovered as electric power. The electric railway system has many elements that can be recovered as electric power, such as converting it into heat energy with a resistor and discarding it. Therefore, the electric railway system converts electric energy into kinetic energy, A type of power storage that can store electrical energy as a result of changing to electrical energy. It is a device. Therefore, by incorporating such an electric railway system in the microgrid, the electric railway system itself can be used as a power storage device.

  5) In the microgrid of the present invention, in particular, the power supply facility in the electric railway system supplies a large amount of electric power for a short time (for example, several tens of seconds) to accelerate the train, while the decelerating train uses the generator. The so-called regenerative brake is used to generate a large amount of current to collect regenerative power, and the power consumption and regenerative power are each pulsed, making it difficult to level consumption and regeneration. The consistency between the two is actually maintained by increasing the number of units and leveling the train, or by storing electric energy as kinetic energy. On the other hand, since the microgrid has been built by relying on storage batteries and power generation devices, it has been impossible to make it economically feasible. By doing so, a microgrid can be established economically.

  6) For example, as described in claim 2, when a secondary battery is connected to a feeder, if the secondary battery is installed in a substation, the secondary battery can be used to level the power. Rechargeable batteries installed at substations balance power supply and demand when installing power generation facilities that use natural energy, as well as power flexibility between train powering and regeneration. Also useful as a battery for. Originally, in a power generation facility using natural energy that requires a battery, the battery installed in the power plant can be substituted, and thus the facility cost is reduced.

  Below, an embodiment is described based on a drawing about a microgrid using an electric railway system concerning the present invention.

  FIG. 1 is a block diagram conceptually showing an embodiment of a microgrid according to the present invention. FIG. 2 is an explanatory view showing an example of a DC electrification type power feeding system in the electric railway system D used in the microgrid 1 of this embodiment, and at the same time, shows an example of the flow of electricity from the DC substation to the train. FIG. 3 shows that the load (power consumption) and power generation (power recovery) in the electric railway system D used in the microgrid 1 of the embodiment of the present invention change in a pulse shape within a short time (for example, several seconds to several tens of seconds). It is a graph of the electric power change and voltage change between 8 am and 8: 5 showing the state to carry out.

  The microgrid 1 of this example is incorporated in the microgrid using an electric railway system D as shown in FIG. 1, and a station building 3 is provided along the track 2. In addition, a plurality of sets of multiple trains 4 are located. In this example, the track 2 is composed of a main track 2a that is continuous in a loop shape and a linear sub track 2b that is orthogonal to the main track 2a. In practice, however, the track 2 is at least a certain area where double track tracks are laid. Can be the demand area for microgrids. In addition, the electric railway system D in the microgrid 1 of the present invention is intended for a subway, a tram, etc. in addition to a train traveling on the ground.

  In addition, the electric railway system (hereinafter referred to as electric railway system) D used in this example includes a DC electrification type power feeding system, and from the AC power source 14 of the commercial power system B to the high voltage transmission line 15 as shown in FIG. The AC power sent by the car is lowered to a predetermined voltage by the transformer C1 via the electric railway substation (hereinafter referred to as the electric railway substation) C, converted to DC power by the rectifier C2, and then the train 4 or the station building 3 To supply. That is, the rectifier C2 has a positive terminal connected to a feeder 5 laid in parallel with the track 2 from the railway substation C, and a negative terminal connected to a track 2 as a return line by a distribution line 14 respectively. ing. Each train 4 is supplied with DC power from the overhead line 6 through a feeder line 5 via a pantograph 7 as a current collector. If the train 4 is equipped with a direct current traveling motor, the direct current power is used as it is. If the alternating current traveling motor is mounted, the train 4 is used after being converted into alternating current by a power control device on the vehicle. To do. The station building 3 is supplied with AC power that has been stepped down by a transformer C1 from an electric railway substation C via a feeder line 5 or a high-voltage distribution line (not shown). In the case of this example, a nickel metal hydride battery 9a, which will be described later, is installed as a secondary battery 9 in the electric railway substation C.

  Among these power supply systems, in the microgrid 1 of this example, the feeder 5 is used as its transmission line (self-operated line or distribution line). The feeder 5 is usually provided with characteristics suitable for the operation of the train 4, and uses a hard steel strand or a hard aluminum strand with low electrical resistance, and is sufficiently insulated from the surroundings. Therefore, the quality as a transmission line is extremely high. Moreover, since it is stretched around the demand area along the track 2, it is perfect as a power grid for a microgrid. Therefore, for example, when a facility such as a distributed power supply device 8 to be described later is provided in a factory or the like away from the track 2, it is only necessary to lay a power transmission line 12 that connects between the facility and the electric wire 5. Further, the microgrid 1 of this example includes a distributed power supply device 8 and a secondary battery 9 connected to the feeder 5.

  The distributed power unit 8 includes a combustion generator using a prime mover such as a diesel engine, a gas turbine, and a gas engine, a wind power generator, a solar cell (solar power generator), a biomass power generator, a small hydroelectric generator, and a fuel cell. In this example, the wind power generator 8a and the solar cell 8b are illustrated. The solar cell 8 b is installed on the roof of the station building 3 and connected to the feeder 5. The wind power generator 8a is installed at a location (not shown) slightly away from the station building 3 of the sub track 2b, and is connected to the feeder 5 via the newly laid transmission line 12. In a generator that generates DC power, such as the solar battery 8b, in the case of DC feeding, it is connected to the feeder 5 via a DC / AC converter, and normally generates AC power, such as a wind generator. In the case of a machine, it goes without saying that it must be connected to the electric wire 5 via an AC / DC converter.

  Examples of the secondary battery 9 include a lead storage battery, a nickel / cadmium storage battery, a NAS (sodium / sulfur) battery, a three-dimensional nickel hydride battery capable of rapid charge / discharge with a large capacity, and a lithium ion battery. Uses a nickel metal hydride battery 9a and a lithium ion battery 9b. The nickel metal hydride battery 9 a is directly connected to the feeder 5, and the lithium ion battery 9 b is connected to the feeder 5 via a chopper as the charge / discharge control device 13. The nickel metal hydride battery 9 a installed in the electric railway substation C is directly connected to the feeder 5. That is, the positive electrode side terminal of the nickel metal hydride battery 9 a is connected to the electric wire 5 by the one distribution line 14 described above, and the negative electrode side terminal is connected to the track 2 as a return line by the other distribution line 14.

  In this way, each of the secondary batteries 9 is connected to the electric wire 5 directly or via the charge / discharge control device 13, and the power is insufficient (the voltage of the overhead wire 6 drops and the electric wire 5 continues to be connected). When the voltage drops), the stored electric power is supplied to the load such as the train 4 via the feeder 5. On the other hand, when the power in the feeder 5 becomes surplus with respect to the load (the voltage of the feeder 5 increases), the surplus power is charged in the secondary battery 9 and stored.

  In the electric railway system D of this example, each train 4 is equipped with a regenerative brake, and regenerative power is generated by braking using the regenerative brake when the train 4 decelerates. For example, if there is a power train 4 nearby, the regenerative power is supplied to the power train 4 via the feeder 5 or the overhead line 6 so that the power consumption of the train 4 during power The voltage drop of the electric wire 5 and the overhead wire 6 can be prevented. Further, if there is no power running train 4 nearby, the regenerative power generated during braking becomes surplus power, and the secondary battery 9 is charged via the feeder 5.

  Further, the station building 3 is equipped with an elevator 10, and the potential energy when the elevator 10 descends can be recovered as regenerative power and charged to the secondary battery 9 via the feeder 5. Recovery of regenerative power is possible, for example, if the elevator 10 includes an inverter that can regenerate.

  By the way, after being converted by the charge / discharge control device 13 so as to be a predetermined voltage (for example, 750 V or 1500 V) in the DC system so as to be adapted to the power supplied by the feeder 5, The secondary battery 9 is charged or supplied to the accelerating train 4. In a device that generates direct current electricity, such as the solar battery 8b, it is connected to the feeder 5 after being adjusted to a predetermined voltage using a DC / DC converter. In addition, if a DC generator is used for the generator for generating regenerative power or the generator 8a for wind power generation, the power conversion device 13 such as an AC / DC converter becomes unnecessary.

  In the microgrid 1 of this example, as shown in FIG. 4, the time zone at the time of peak output of power is shifted from the time zone of peak output in the commercial power system B that receives power supply. Thus, since the microgrid 1 of this example and the commercial power system are in a complementary relationship, by coordinating with the commercial power system, the power demand in the region can be balanced and effective for the local economy. To work.

  In addition, a power trading meter for measuring the amount of power supplied (sold) from the microgrid 1 to the system B, for example, a transformer for current transformer (MOF) 16 is installed at the receiving point of the electric railway substation C. The instrumental transformer current transformer 16 measures the amount of power when power is supplied from the microgrid 1 to the commercial power system B.

  In addition, by replenishing power from the secondary battery 9 at the time of peak power output in the electric grid system D of the microgrid 1, the usable peak power value received from the commercial power system B can be suppressed to reduce costs. I try to figure it out. In other words, the peak power value generated in the microgrid 1 during peak output (usually during rush hour) is discharged from the secondary battery 9 and supplemented to replenish the power supplied from the commercial power system B. The peak value can be suppressed, and the contract power charge can be reduced.

  Although the embodiment of the microgrid of the present invention has been described above, the microgrid of the present invention can be implemented as follows.

  -Although the said Example demonstrated the microgrid combined with the electric railway system D of a direct current electrification system, even if it comprises a microgrid in combination with the electric railway system of an alternating current electrification system, it can implement similarly.

  A capacitor or a double electric layer capacitor can be used in place of the secondary battery 9.

It is a block diagram which shows the Example of the microgrid of this invention notionally. It is explanatory drawing which shows an example of the electric power feeding system E of the direct current electrification system in the electric railway system D utilized with the microgrid 1 of a present Example, and shows simultaneously an example of the flow of electricity from a direct current substation to a train. The load (electric power consumption) and power generation (electric power recovery) in the electric railway system D used in the microgrid 1 of the present embodiment represents a state in which the pulse changes in a short time (for example, several seconds to several tens of seconds). It is a graph of the electric power change and voltage change between 8 am and 8:05. The peak of power demand in the commercial power system B is once around 2:00 in the afternoon, whereas the peak of power demand in the electric railway system D is early morning (around 7-9 am) and evening (5-8 pm). It is a graph showing the electric power change of the day which shows that it is 2 times. It is a SOC characteristic figure which shows the voltage change with respect to SOC of a secondary battery from which a kind differs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Microgrid 2 Track 2a Main track 2b Sub track 3 Station building 4 Train 5 Feed wire 6 Overhead wire 7 Pantograph 8 Distributed power supply device 8a Wind power generator 8b Solar battery (solar power generator)
9 Secondary battery 9a Nickel metal hydride battery 9b Lithium ion battery 12 Transmission line 13 Power converter (chopper, inverter, converter, etc.)
15 High-voltage transmission line C Electric railway substation (hereinafter referred to as electric railway substation)
C1 transformer
C2 Rectifier D Electric railway system (hereinafter referred to as electric railway system)

Claims (9)

In an electric railway system equipped with electric railway power supply facilities including electric railway substations and feeders,
A microgrid using an electric railway system, wherein the feeder is used as a transmission line.   The microgrid using the electric railway system according to claim 1, wherein a secondary battery is connected to the feeder.   The microgrid using the electric railway system according to claim 2, wherein the secondary battery is a nickel metal hydride battery.   The microgrid using the electric railway system according to any one of claims 1 to 3, wherein a power generation facility using natural energy is connected to the feeder.   The microgrid using the electric railway system according to any one of claims 1 to 4, wherein a private power generation facility is connected to the feeder.   The microgrid using the electric railway system according to any one of claims 1 to 5, wherein the feeder is connected to a commercial power system via a power trading instrument.   The microgrid using the electric railway system according to any one of claims 1 to 5, wherein a regenerative brake that is operated when the electric railway vehicle is decelerated is provided in the electric railway vehicle.   The microgrid using the electric railway system according to any one of claims 1 to 5, wherein means for converting potential energy into regenerative power is provided in an elevator, a crane, and other devices that generate potential energy.   The microgrid using the electric railway system according to any one of claims 1 to 5, wherein means for converting magnetic energy into regenerative power is provided in an electric motor, an electromagnet, a transformer, and other devices that generate magnetic energy.

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