JP2021197766A - Power network - Google Patents

Abstract

To provide a power network capable of autonomously transferring electric power from one power network to another power network without the need of power conversion in a communication power line when transferring power from the one power network to the other power network.SOLUTION: A power network includes: a first power reception point connected to a commercial power system of AC; a first power network to which electric power of the commercial power system is supplied from the first power reception point; a second power reception point connected to the commercial power system of AC; and a second power network to which power of the commercial power system is supplied from the second power reception point. The first power network has a demand peak of power different from that of the second power network. The first and second power networks linked by a DC line, and power can be supplied between the first power network and the second power network.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electric power network in which a plurality of electric power networks are interconnected by an interconnection line, and more particularly to an electric power network in which a plurality of electric power networks having different demand peaks are interconnected in an interconnection line of a DC line.

The conventional power grid (grid) is an independent power network separated from the commercial power system, which is an external power system, or a power network having one receiving point with the commercial power system. When there are multiple power grids with one power receiving point with the commercial power system, each power grid is controlled by adjusting the supply-demand balance in the power grid and the amount of power received at the linking point with the commercial power system. There is.

On the other hand, electric power consumers purchase electric power from electric power companies, and the tariff system consists of a pay-as-you-go charge proportional to the amount of electric power and a basic charge depending on the peak value of electric power. In particular, for consumers who receive power at high voltage higher than high voltage, the ratio of the basic charge is large, and reducing the power peak is important for saving the power charge. Therefore, it has been proposed to connect multiple power grids with different peak power demands with interconnection power lines and to suppress peak power by accommodating power from a power grid with low power demand to a power grid with high power demand via the interconnection power line. ing.

The commercial power system uses AC power for power transmission and distribution because it is easy to transform. However, when power is exchanged between a plurality of power grids using alternating current, it is necessary to send power in phase with the voltage. Therefore, after converting AC power to DC power on one power grid side, power is sent from one power grid side to the other power grid side, and again, DC power is converted to AC power on the other power grid side. Power was interchanged from a power grid with a small power demand to a power grid with a large power demand (Patent Document 1).

According to Patent Document 1, when power is transferred from a power grid with a small power demand to a power grid with a large power demand, two power conversions are required as described above, and a part of the power is lost by this power conversion. There was a problem. In addition, when introducing a power converter for returning from DC power to AC power, it is necessary to meet the grid interconnection requirements, which could be an obstacle when further expanding the power grid.

When accommodating electric power between power grids using alternating current, it is necessary to actively specify the amount of electric power to operate the electric power accommodating device. Therefore, it is necessary to schedule the power interchange based on the prior information of the power consumption, or to accommodate the power using the power amount calculated based on the power demand as a command value (Patent Document 2).

Patent No. 6271209 Patent No. 5364768

Due to the above circumstances, the present invention does not require power conversion in the interconnection power line when power is transferred from one power grid to the other power grid, does not need to satisfy the grid interconnection requirements, and is autonomously one of them. It is an object of the present invention to provide an electric power network capable of exchanging electric power from one electric power grid to the other electric power grid.

The gist of the structure of the present invention is as follows.
[1] A first power receiving point connected to an AC commercial power system, and a first power network to which power of the commercial power system is supplied from the first power receiving point.
It has a second power receiving point connected to the AC commercial power system and a second power network to which power of the commercial power system is supplied from the second power receiving point.
The first power grid has a different peak demand for power from the second power grid.
A power network in which the first power network and the second power network are interconnected by a DC line so that power can be supplied between the first power network and the second power network.
[2] The power network according to [1], wherein at least one of the first power grid and the second power network has a power generation device that generates power using renewable energy.
[3] The amount of power generated per unit time of the power generation device that generates power using the renewable energy of the first power network is per unit time of the power generation device that generates power using the renewable energy of the second power network. The power network according to [2], which is different from the amount of power generated in.
[4] The power network according to any one of [1] to [3], wherein at least one of the first power grid and the second power network has a stationary power storage device.
[5] The power network according to [4], wherein the charging capacity of the stationary power storage device of the first power grid is different from the charging capacity of the stationary power storage device of the second power grid.
[6] The first power grid inputs and outputs electric power of a device constituting the first power network based on the own end voltage, and the second power network receives the second power based on the own end voltage. The power network according to any one of [1] to [5], which inputs and outputs power to and from a device constituting the power grid.
[7] The first power converter of the first power grid is connected to the first power receiving point, and the second power converter of the second power grid is connected to the second power receiving point. The power network according to any one of [1] to [6].
[8] The power network according to any one of [1] to [7], wherein the DC line is provided with a DC / DC converter.
[9] The voltage of the DC line is boosted above the voltage of the first power network by the first power grid side DC / DC converter provided between the first power network and the DC line, and the first power grid is described. To any one of [1] to [7], which is boosted above the voltage of the second power grid by the second power grid side DC / DC converter provided between the second power grid and the DC line. The power grid described.

"The peak demand for electric power is different" in the above [1] means that the time zone of the peak demand for electric power is different between the first power grid and the second power grid, or the time zone of the peak demand is the same or overlaps. Even so, it means that the amount of power required is different.

According to the aspect of the electric power network of the present invention, the first electric power grid and the second electric power grid having different peaks of electric power demand are connected by a DC line, and the electric power is connected between the first electric power grid and the second electric power grid. By being able to supply power, when power is transferred from one power grid to the other power grid, power conversion on the interconnection power line is not required, it is not necessary to meet grid interconnection requirements, and power demand is met. Accordingly, it is possible to autonomously transfer power from one power grid to the other power grid. Therefore, since the power generation equipment of each power grid can be reduced or minimized, the investment related to the power generation equipment can be significantly reduced.

According to the aspect of the power network of the present invention, at least one of the first power grid and the second power network has a power generation device that generates power using renewable energy, so that the renewable energy can be reduced while reducing the environmental load. The power from the power generation device that is used to generate electricity can be autonomously transferred from one power grid to the other power grid while maintaining the DC current. Therefore, it is possible to improve the utilization efficiency of renewable energy.

According to the aspect of the power network of the present invention, since at least one of the first power grid and the second power network has the stationary power storage device, the power grid having the stationary power storage device has a stationary power storage device during a time period when the power consumption is low. By charging the power storage device and discharging the stationary power storage device during times when the power grid consumes a lot of power, it is possible to cover part of the power consumption of the power grid. In addition, if necessary, it is possible to cover part of the power consumption of the power grid by independently accommodating the power discharged from the stationary power storage device from one power grid to the other power grid while maintaining the direct current. can. Therefore, it is possible to reduce the amount of commercial power supplied from the external power system while reducing the equipment cost of the stationary power storage device.

According to the aspect of the power network of the present invention, the first power network inputs and outputs the power of the device constituting the first power network based on the own end voltage, and the second power network is the second based on the own end voltage. Since the power of the devices constituting the power grid of 2 can be input and output, it is not necessary to control the entire power network, and the operation of power interchange between the power grids is easy.

According to the aspect of the power network of the present invention, since the DC / DC converter is provided in the DC line, the first is based on the self-end voltage of the first power grid and the self-end voltage of the second power grid. It is possible to interchange power between the first power grid and the second power grid. In addition, the first power network and the second power network are based on a preset power accommodation plan such as scheduling power interchange based on prior information on power consumption and command values of power amount calculated based on power demand. It is also possible to exchange power with and from. Further, when an isolated converter is used as the DC / DC converter, even if an accident occurs in one power grid, it is possible to prevent the influence of the accident from affecting the other power grid.

According to the aspect of the power network of the present invention, the voltage of the DC line is boosted above the voltage of the first power grid by the first power grid side DC / DC converter, and is boosted by the second power grid side DC / DC converter. Since the voltage is higher than the voltage of the second power grid, a large amount of power can be accommodated even if the distance between the first power grid and the second power grid is large. Further, the diameter of the DC line and the amount of metal used for the conductor of the DC line can be reduced, and further, the transmission loss when power is exchanged between the first power grid and the second power network can be reduced. By keeping the boost ratio of the first power grid side DC / DC converter and the boost ratio of the second power grid side DC / DC converter constant, the self-end voltage of the first power grid and the second power network With the self-end voltage of, the power can be interchanged independently.

It is a schematic block diagram of the electric power network which is 1st Embodiment of this invention. It is a schematic block diagram of the electric power network which is 2nd Embodiment of this invention. It is a schematic block diagram of the electric power network which is 3rd Embodiment of this invention. It is a schematic block diagram explaining the Example of the electric power network which is 3rd Embodiment of this invention. It is a graph which shows the electric power pattern in the 1st electric power grid and the 2nd electric power grid in the Example of the electric power network which is 3rd Embodiment of this invention.

<First Embodiment>
First, the power network according to the first embodiment of the present invention will be described. Note that FIG. 1 is a schematic configuration diagram of a power network according to the first embodiment of the present invention. The power network 1 according to the first embodiment has a plurality of power grids (grids), and in FIG. 1, it has two power networks (grids), a first power network 10 and a second power network 20. There is. The first power grid 10 and the second power grid 20 are connected by a DC line 50.

As shown in FIG. 1, the first power grid 10 receives power from an AC commercial power system 100, which is an external power system, via a first power receiving point 101. Therefore, the power network 1 has a first power receiving point 101 connected to the AC commercial power system 100 and a first power network 10 to which power of the commercial power system 100 is supplied from the first power receiving point 101. Have. Further, the second power grid 20 receives the power of the AC commercial power system 100 that the first power grid 10 is receiving through the second power receiving point 102. Therefore, the power network 1 has a second power receiving point 102 connected to the AC commercial power system 100 and a second power network 20 to which power of the commercial power system 100 is supplied from the second power receiving point 102. Have.

From the above, the AC commercial power system 100 supplies power to a plurality of power grids (first power grid 10 and second power network 20 in FIG. 1), respectively. Further, the first power grid 10 and the second power grid 20 have mutually independent power receiving points with respect to the AC commercial power system 100.

The first power grid 10 is an AC / DC converter 11 that can be connected to an AC commercial power system 100 and converts AC power input from the AC commercial power system 100 into DC power and outputs the AC / DC converter 11. A DC bus 19 connected to the output of the converter 11, a charger connected to the DC bus 19 and connectable to a storage battery to be charged (EV charger 17 in the first power grid 10), and a DC bus. A charge / dischargeable stationary power storage device 14 connected to 19 and a solar power generation device (PV) 15 connected to a DC bus 19 which is a power generation device that generates power using renewable energy are provided. There is. From the above, the first power grid 10 is a DC grid. In the first power grid 10, the storage battery is, for example, an in-vehicle storage battery which is a storage battery mounted on an electric vehicle (EV) 18. The output of the DC bus 19 is connected to the EV charger 17, and the in-vehicle storage battery of the electric vehicle 18 is connected to the EV charger 17 to charge the in-vehicle storage battery. The stationary power storage device 14 is an in-equipment power storage device of the first power grid 10.

In the first power grid 10, the AC / DC converter 11 receives power from the commercial power system 100 as a control unit (not shown) so that the commercial power system 100 does not take in power exceeding the upper limit. It is controlled by. Further, the control unit controls charging / discharging of the stationary power storage device 14, discharging of the photovoltaic power generation device 15, and charging of the in-vehicle storage battery of the electric vehicle 18 connected to the EV charger 17.

The second power grid 20 can be connected to the AC commercial power system 100, and has an AC / DC converter 21 that converts the AC power input from the AC commercial power system 100 into DC power and outputs the AC / DC. A DC bus 29 connected to the output of the converter 21, a charger connected to the DC bus 29 and connectable to a storage battery to be charged (EV charger 27 in the second power grid 20), and a DC bus. A charge / dischargeable stationary power storage device 24 connected to 29 and a solar power generation device (PV) 25 connected to a DC bus 29, which is a power generation device that generates power using renewable energy, are provided. There is. From the above, the second power grid 20 is a DC grid. In the second power grid 20, the storage battery is, for example, an in-vehicle storage battery which is a storage battery mounted on an electric vehicle (EV) 28. The output of the DC bus 29 is connected to the EV charger 27, and the vehicle-mounted storage battery of the electric vehicle 28 is connected to the EV charger 27 to charge the vehicle-mounted storage battery. The stationary power storage device 24 is an in-equipment power storage device of the second power grid 20.

In the second power grid 20, the AC / DC converter 21 receives power from the commercial power system 100 as a control unit (not shown) so that the commercial power system 100 does not take in power exceeding the upper limit. It is controlled by. Further, the control unit controls charging / discharging of the stationary power storage device 24, discharging of the photovoltaic power generation device 25, and charging of the in-vehicle storage battery of the electric vehicle 28 connected to the EV charger 27.

From the above, in the power network 1, the AC / DC converter 11 of the first power network 10 is connected to the first power receiving point 101, and the AC / DC converter 21 of the second power network 20 is connected to the second receiving point 102. Is connected to.

The operation of the first power grid 10 and the second power grid 20 will be described below. Since the operations of the first power grid 10 and the second power grid 20 are basically common, the operation of the first power grid 10 will be described here as an example.

In the first power network 10, the user of the EV charger 17 stops the electric vehicle 18 at the installation location of the EV charger 17, connects the in-vehicle storage battery of the electric vehicle 18 to the EV charger 17, and connects the EV charger 17. The operation unit requests the EV charger 17 to start charging the electric vehicle 18. The control unit of the first power network 10 receives an instruction to start charging from the operation unit of the EV charger 17, and when the connection of the in-vehicle storage battery of the electric vehicle 18 to the EV charger 17 is confirmed, the EV charger 17 sends the control unit. The charging process for the in-vehicle storage battery of the electric vehicle 18 is started. At this time, the control unit of the first power network 10 determines whether or not the amount of current from the EV charger 17 to the in-vehicle storage battery of the electric vehicle 18 is equal to or less than the contract power of the commercial power system 100.

When the amount of current from the EV charger 17 to the in-vehicle storage battery of the electric vehicle 18 exceeds the contracted power of the commercial power system 100, a predetermined value of power is supplied from the stationary power storage device 14 to the DC bus 19, and the stationary power storage is performed. The electric power supplied from the device 14 to the DC bus 19 is supplied to the EV charger 17 as a charging current. The difference between the required power and the contract power of the commercial power system 100 is supplemented by the power supplied from the stationary power storage device 14 to the DC bus 19, that is, the power discharged by the stationary power storage device 14. Further, during the daytime, the electric power generated by the solar power generation device 15 is supplied to the DC bus 19, is supplied from the DC bus 19 to the EV charger 17, and is mounted on the electric vehicle 18 connected to the EV charger 17. The storage battery is charged. That is, the photovoltaic power generation device 15 can be used as a supplementary power source for the commercial power system 100 and as an alternative power source for the commercial power system 100. The photovoltaic power generation device 15 is a power source that can be used in combination with the commercial power system 100. By providing the photovoltaic power generation device 15, the electric power supplied from the commercial power system 100 can be further reduced, and the load on the stationary power storage device 14 can be reduced.

On the other hand, when the amount of current from the EV charger 17 to the in-vehicle storage battery of the electric vehicle 18 is equal to or less than the contract power of the commercial power system 100, a predetermined value of power is supplied from the DC bus 19 to the stationary power storage device 14. , The stationary power storage device 14 is charged. By supplying electric power from the DC bus 19 to the stationary power storage device 14 to charge the stationary power storage device 14, the stationary power storage device 14 can proceed with preparations for charging the next electric vehicle 18. .. When the power required from the in-vehicle storage battery of the electric vehicle 18 is equal to or less than the contract power of the commercial power system 100, the solar power generation device 15 supplies power to the stationary power storage device 14 to provide the stationary power storage device 14. Can be charged. The charging of the stationary power storage device 14 and the charging of the in-vehicle storage battery of the electric vehicle 18 from the EV charger 17 may be performed in parallel.

As described above, when the power demand in the first power grid 10 is large, the voltage of the first power grid 10 is stabilized by discharging the stationary power storage device 14 to the DC bus 19. On the other hand, when the power demand in the first power grid 10 is low or the amount of power generated by the photovoltaic power generation device 15 is large, the voltage of the first power grid 10 is maintained by charging the stationary power storage device 14. .. Since the stationary power storage device 14 is charged and discharged according to the voltage at the end of the first power grid 10, the first power grid 10 can stably supply electric power by simple control.

As described above, the first power grid 10 and the second power grid 20 are distributed and controlled by their respective control units based on their own voltage. The first power grid 10 receives power from a device (in the power network 1, a stationary power storage device 14, a photovoltaic power generation device 15, an EV charger 17) that constitutes the first power network 10 based on its own voltage. Output. Further, the second power grid 20 is the power of the device constituting the second power network 20 based on its own voltage (in the power network 1, the stationary power storage device 24, the photovoltaic power generation device 25, and the EV charger 27). Input / output of.

Further, in the electric power network 1, the first electric power network 10 is an electric power network having a different peak demand for electric power from the second electric power network 20.

As shown in FIG. 1, the DC bus 19 of the first power grid 10 and the DC bus 29 of the second power grid 20 are connected via a DC line 50. That is, the first power grid 10 and the second power grid 20 are connected by a DC line 50. Therefore, the DC line 50 functions as an electric power interconnection line, can supply electric power between the first electric power grid 10 and the second electric power grid 20, and can be supplied from the first electric power grid 10 to the second electric power grid 20. Further, power can be interchanged from the second power grid 20 to the first power grid 10. In the power network 1, both the DC bus 19 of the first power grid 10 and the DC bus 29 of the second power grid 20 are directly connected to the DC line 50. Further, the DC line 50 is not provided with a device such as a power converter.

For example, if the first power grid 10 is in the peak time zone of power demand and the second power grid 20 is not in the peak time zone of power demand, the second power grid 20 has a margin in power supply, so that DC is used. Power can be interchanged from the second power grid 20 to the first power grid 10 via the line 50. At this time, since the voltage of the second power grid 20 is higher than the voltage of the first power grid 10, the DC line 50 automatically obtains the first voltage based on the voltage difference between the first power grid 10 and the second power grid 20. Power can be sent from the second power grid 20 to the first power grid 10.

From the above, by connecting the first power grid 10 and the second power grid 20 with the DC line 50, changes in the power demand of the first power grid 10 and the second power grid 20 and the changes in the power demand of the solar power generation devices 15 and 25 can be obtained. Changes in the amount of power generation can be mitigated by adjusting the charge / discharge amount of the stationary power storage device 14 of the first power grid 10 and the stationary power storage device 24 of the second power network 20 and the amount of power received from the commercial power system 100. ..

In the power network 1, the first power grid 10 and the second power grid 20 having different power demand peaks are connected by a DC line 50, and power is supplied between the first power grid 10 and the second power network 20. Therefore, when power is transferred from one power grid to the other power grid, power conversion in the interconnection power line connecting the first power grid 10 and the second power grid 20 is not required. , It is not necessary to meet the grid interconnection requirements. Further, in the power network 1, power can be independently interchanged from one power grid to the other power network according to the power demand of the first power grid 10 and the second power network 20. Therefore, since the power generation facilities of the first power grid 10 and the second power grid 20 can be reduced and minimized, the investment related to the power generation facilities can be significantly reduced.

Further, in the power network 1, the first power grid 10 has the photovoltaic power generation device 15, so that the power from the photovoltaic power generation device 15 can be independently transmitted as a DC current while reducing the environmental load. It is possible to accommodate from the power grid 10 of the above to the second power grid 20. Further, since the second power grid 20 has the photovoltaic power generation device 25, the power from the photovoltaic power generation device 25 can be independently transferred from the second power grid 20 to the second power grid 20 while reducing the environmental load. It can be accommodated to the power grid 10 of 1. Therefore, in the electric power network 1, it is possible to improve the utilization efficiency of renewable energy.

Further, in the power network 1, since the first power grid 10 has the stationary power storage device 14, the stationary power storage device 14 is charged during a time period when the power consumption of the first power network 10 is low, and the first power network 10 is charged. By discharging the stationary power storage device 14 during a time period when the power consumption of the first power grid is high, a part of the power consumption of the first power grid 10 can be covered. Further, since the second power grid 20 has the stationary power storage device 24, the stationary power storage device 24 is charged during a time period when the power consumption of the second power network 20 is low, and the power consumption of the second power network 20 is high. By discharging the stationary power storage device 24 in the time zone, it is possible to cover a part of the power consumption of the second power grid 20. Further, if necessary, the electric power discharged from the stationary power storage device 14 from the first power grid 10 to the second power grid 20 is autonomously accommodated as the DC current, thereby consuming the second power grid 20. A part of the electric power can be supplied, and the electric power discharged from the stationary power storage device 24 from the second electric power grid 20 to the first electric power grid 10 is autonomously interchanged with the DC current as it is, so that the first electric power grid can be supplied. It can cover a part of the power consumption of 10. Therefore, it is possible to reduce the power consumption of the commercial power system 100 while reducing the equipment cost of the stationary power storage devices 14 and 24. Further, since the first power grid 10 and the second power grid 20 are DC grids, it is easy to add stationary power storage devices 14 and 24 and solar power generation devices 15 and 25.

Further, in the power network 1, as described above, the first power network 10 inputs and outputs the power of the devices constituting the first power network 10 based on the own end voltage, and the second power network 20 becomes the own end voltage. Since the power of the device constituting the second power grid 20 is input and output based on the above, it is not necessary to control the entire power network 1, and the operation of power interchange between the power grids is easy.

In the power network 1, the amount of power generated per unit time of the photovoltaic power generation device 15 of the first power grid 10 is the same as the amount of power generated per unit time of the photovoltaic power generation device 25 of the second power grid 20. May be good. For example, due to the difference in the installable area of the photovoltaic power generation devices 15 and 25, the amount of power generated per unit time of the photovoltaic power generation device 15 of the first power grid 10 is the unit of the photovoltaic power generation device 25 of the second power grid 20. Even if the amount of power generation per hour is different, the DC line 50 can automatically transfer power between the first power grid 10 and the second power grid 20. Therefore, even if the amount of power generated by the photovoltaic power generation device 15 of the first power network 10 and the amount of power generated by the photovoltaic power generation device 25 of the second power network 20 are different, the photovoltaic power generation as the power network 1 by the DC line 50 The amount of power generated by the devices 15 and 25 can be leveled, and the equipment of the photovoltaic power generation devices 15 and 25 can be optimized.

Further, in the power network 1, the charging capacity of the stationary power storage device 14 of the first power network 10 may be the same as or different from the charging capacity of the stationary power storage device 24 of the second power network 20. For example, due to differences in the installable area of the stationary power storage devices 14 and 24 and the magnitude of the power demand peak, the charging capacity of the stationary power storage device 14 of the first power grid 10 becomes the stationary power storage of the second power network 20. Even if the charging capacity of the device 24 is different, the DC line 50 can automatically transfer electric power between the first power grid 10 and the second power grid 20. Therefore, even if the charging capacity of the stationary power storage device 14 of the first power network 10 is different from the charging capacity of the stationary power storage device 24 of the second power network 20, the DC line 50 is a stationary type as the power network 1. The charging capacities of the power storage devices 14 and 24 can be leveled, and the equipment of the stationary power storage devices 14 and 24 can be optimized.

<Second Embodiment>
Next, the power network according to the second embodiment of the present invention will be described. Since the electric power network according to the second embodiment of the present invention has the same main components as the electric power network according to the first embodiment, the same components as the electric power network according to the first embodiment are used. This will be described using the same reference numerals. FIG. 2 is a schematic configuration diagram of a power network according to a second embodiment of the present invention.

In the power network 1 according to the first embodiment, the DC bus 19 of the first power network 10 and the DC bus 29 of the second power network 20 are connected via the DC line 50, but instead of this, FIG. As shown in 2, in the power network 2 of the second embodiment, the DC / DC converter 30 is provided on the DC line 50. Therefore, the DC bus 19 of the first power grid 10 and the DC bus 29 of the second power network 20 are connected via a DC / DC converter 30 provided on the DC line 50. The DC / DC converter 30 is a bidirectional DC / DC converter and functions as a power interchange converter.

In the power network 2, the DC is based on the charge rate (SOC) of the stationary power storage devices 14 and 24, the power generation amount prediction of the solar power generation device 15, the power demand prediction of the first power grid 10 and the second power grid 20 and the like. By controlling the power transmission direction and the input / output amount of the / DC converter 30 with a control unit (not shown), optimum power interchange can be performed between the first power grid 10 and the second power grid 20. ..

Since the DC / DC converter 30 is provided on the DC line 50, the first power grid 10 and the second power grid 10 and the second power grid 10 are based on the self-end voltage of the first power grid 10 and the self-end voltage of the second power grid 20. Regardless of the voltage difference between the power grid 20 and the power grid 20, power can be interchanged between the first power grid 10 and the second power grid 20. Therefore, by measuring the self-end voltage of the first power grid 10 and the self-end voltage of the second power grid 20 with the sensor unit (not shown), the self-end voltage between the first power grid 10 and the second power grid 20 can be measured. Independent power interchange is possible. Further, if necessary, power interchange is scheduled based on the prior information of the power consumption of the first power grid 10 and the second power network 20, and the command value of the power amount calculated based on the power demand is set in advance. It is also possible to interchange power between the first power grid 10 and the second power grid 20 based on the power interchange plan.

Further, when an isolated converter is used as the DC / DC converter 30, even if an accident occurs in one power grid, it is possible to prevent the influence of the accident from affecting the other power grid.

<Third Embodiment>
Next, the power network according to the third embodiment of the present invention will be described. Since the electric power network according to the third embodiment of the present invention has the same main components as the electric power network according to the first embodiment, the same components as the electric power network according to the first embodiment are used. This will be described using the same reference numerals. FIG. 3 is a schematic configuration diagram of an electric power network according to a third embodiment of the present invention.

In the power network 1 of the first embodiment, both the DC bus 19 of the first power network 10 and the DC bus 29 of the second power network 20 are directly connected to the DC line 50. Instead of this, as shown in FIG. 3, in the power network 3 according to the third embodiment, the first power grid side DC / DC converter 41 is provided between the first power grid 10 and the DC line 50. A second power grid side DC / DC converter 42 is provided between the second power grid 20 and the DC line 50.

In the power network 3, the voltage of the DC line 50 is higher than the voltage of the first power network 10 by the first power grid side DC / DC converter 41 provided between the first power grid 10 and the DC line 50. ing. Further, the voltage of the DC line 50 is boosted higher than the voltage of the second power network 20 by the second power grid side DC / DC converter 42 provided between the second power grid 20 and the DC line 50. The first power grid side DC / DC converter 41 and the second power grid side DC / DC converter 42 are both bidirectional DC / DC converters. By keeping the boost ratio of the first power grid side DC / DC converter 41 to the voltage of the first power grid 10 and the boost ratio of the second power grid side DC / DC converter 42 to the second power grid 20 constant. , The self-end voltage of the first power grid 10 and the self-end voltage of the second power grid 20 can autonomously exchange power between the first power grid 10 and the second power grid 20.

In the power network 3, based on the charge rate (SOC) of the stationary power storage devices 14 and 24, the power generation amount prediction of the solar power generation devices 15 and 25, the power demand prediction of the first power grid 10 and the second power grid 20, and the like. By controlling the boost ratio of the first power grid side DC / DC converter 41 and the boost ratio of the second power grid side DC / DC converter 42 by a control unit (not shown), the first power grid 10 and Optimal power interchange with the second power grid 20 can be performed.

The voltage of the DC line 50 is preferably twice or more than the voltage of the first power grid 10 and the voltage of the second power grid 20, and is particularly preferably three times or more.

The voltage of the DC line 50 is boosted by the first power grid side DC / DC converter 41 to be higher than the voltage of the first power network 10, and the voltage of the second power network 20 is increased by the second power network side DC / DC converter 42. Even if the distance between the first power grid 10 and the second power network 20 becomes longer, the capacity of the power that can be interchanged via the DC line 50 can be increased. Further, in the power network 3, the diameter of the DC line 50 and the amount of metal used for the conductor of the DC line 50 can be reduced, and further, when power is exchanged between the first power network 10 and the second power network 20. Transmission loss can be reduced.

Next, an embodiment of the power network 3 will be described below. FIG. 4 is a schematic configuration diagram illustrating an embodiment of a power network according to a third embodiment of the present invention. FIG. 5 is a graph showing power patterns in the first power grid and the second power grid in the example of the power network according to the third embodiment of the present invention.

As shown in FIG. 4, in the embodiment of the electric power network 3, the service area (SA) of the expressway will be described as an example. In the embodiment, the power grid in the upstream service area (upstream SA) corresponds to the first power grid 10, and the power grid in the downstream service area (downstream SA) corresponds to the second power grid 20. The upstream SA includes a stationary power storage device 14, a photovoltaic power generation device 15, and a plurality of EV chargers 17, respectively, via a DC / DC converter (indicated as “DC / DC” in FIG. 4). Is connected to the DC bus 19. An in-vehicle storage battery of the electric vehicle 18 is connected to the EV charger 17, and the in-vehicle storage battery of the electric vehicle 18 is charged. The downlink SA includes a stationary power storage device 24, a photovoltaic power generation device 25, and a plurality of EV chargers 27, each via a DC / DC converter (indicated as “DC / DC” in FIG. 4). Is connected to the DC bus 29. An in-vehicle storage battery of the electric vehicle 28 is connected to the EV charger 27, and the in-vehicle storage battery of the electric vehicle 28 is charged.

The uplink SA and the downlink SA are connected via the DC line 50, a first power grid side DC / DC converter 41 is provided between the uplink SA and the DC line 50, and a second power grid side DC / DC converter 41 is provided between the downlink SA and the DC line 50. The DC / DC converter 42 on the power grid side of the above is provided. In the embodiment, the voltage of the first power grid 10 and the second power grid 20 is 380V, and the DC line 50 is provided by the first power grid side DC / DC converter 41 and the second power grid side DC / DC converter 42. The voltage of is boosted to 1.5 kV.

The number of EV chargers 17 and 27 installed, the number of stationary power storage devices 14 and 24 installed, and the number of photovoltaic power generation devices 15 and 25 installed can be appropriately selected depending on usage conditions and the like. In FIG. 4, for convenience of explanation, the number of the upstream SA EV charger 17 and the downstream SA EV charger 27 is 10 each, and the upstream SA stationary power storage device 14, the solar power generation device 15, and the downstream SA stationary type are used. The power storage device 24 and the solar power generation device 25 are each one.

As shown in FIG. 5, in the ascending SA and the descending SA, the peak time zone of the power consumption differs depending on the time zone of the traffic volume of the electric vehicle 28. Further, during the daytime hours, the photovoltaic power generation devices 15 and 25 generate power. Further, the peak time zone of the power generation amount (PV power generation amount) of the photovoltaic power generation devices 15 and 25, the peak time zone of the power consumption amount of the upstream SA, and the peak time zone of the power consumption amount of the downstream SA are different.

From the above, for example, from 6 o'clock to 11 o'clock, the power consumption of the downlink SA is much larger than the power consumption of the uplink SA. Therefore, from 6 o'clock to 11 o'clock, the power of the upstream SA is transferred to the downstream SA via the DC line 50. Further, if necessary, the electric power discharged from the stationary power storage device 14 of the upstream SA is accommodated to the downstream SA. On the other hand, from 14:00 to 19:00, the power consumption of the uplink SA is much larger than the power consumption of the downlink SA. Therefore, from 14:00 to 19:00, the power of the downlink SA is transferred to the uplink SA via the DC line 50. Further, if necessary, the electric power discharged from the stationary power storage device 24 of the downlink SA is accommodated to the uplink SA. Further, in the peak time zone of the power generation amount of the photovoltaic power generation devices 15 and 25 (for example, from 12:00 to 13:00), the power generation of the photovoltaic power generation device 15 can supply all the power consumption required for the upstream SA, and the sun. By the power generation of the photovoltaic power generation device 25, all the necessary power consumption of the downlink SA can be supplied. Further, in the nighttime when the power consumption is low, all the necessary power consumption can be supplied by the amount of power received from the commercial power system 100 for both the upstream SA and the downstream SA. Therefore, surplus power is generated in the peak time zone and the nighttime time zone of the power generation amount of the photovoltaic power generation devices 15 and 25. The surplus electric power is used to charge the stationary power storage devices 14 and 24 to increase the charging rate of the stationary power storage devices 14 and 24. By increasing the charging rates of the stationary power storage devices 14 and 24, the SA is prepared for a time zone in which the power consumption increases.

Therefore, based on the charge rates of the stationary power storage devices 14 and 24, the amount of power generated by the solar power generation devices 15 and 25, the amount of power received from the commercial power system 100, and the capacity of the DC line 50, the stationary power storage devices 14 and 24 By adjusting the charge / discharge amount, the time zone in which power is exchanged between the upstream SA and the downstream SA, and the amount of electric power, it is possible to reduce and minimize the power generation equipment of the power grid of the upstream SA and the downstream SA.

Next, another embodiment of the power network of the present invention will be described. In the power network of each of the above embodiments, the AC / DC converter 11 of the first power network 10 is connected to the first power receiving point 101, and the AC / DC converter 21 of the second power network 20 is the second receiving point. Although it was connected to 102, the position of the AC / DC converter 11 and the position of the AC / DC converter 21 are not particularly limited as long as the DC current can be supplied to the DC line 50 which is a power interconnection line. Therefore, for example, the AC / DC converter 11 may be located between the DC bus 19 and the DC line 50, and the AC / DC converter 21 may be located between the DC bus 29 and the DC line 50. good.

In the power network of each of the above embodiments, the photovoltaic power generation device is provided in each of the first power grid 10 and the second power grid 20, but instead of this, the first power grid 10 and the second power network 20 are provided. A photovoltaic power generation device may be provided in any one of the 20. In the power network of each of the above embodiments, the stationary power storage device is provided in each of the first power grid 10 and the second power grid 20, but instead of this, the first power grid 10 and the second power grid 20 are provided. A stationary power storage device may be provided in any one of the 20s.

In the power grid of each of the above embodiments, there are two power grids having mutually independent power receiving points, the first power grid 10 and the second power grid 20, but instead of this, three or more power grids are used. It may be more than one. Even in the case of three or more power grids, each power grid is interconnected by a DC line which is a power interconnection line.

1, 2, 3 Power network 10 First power network 14 Stationary power storage device 15 Solar power generation device 20 Second power network 24 Stationary power storage device 25 Solar power generation device 50 DC line 100 Commercial power system 101 First power receiving point 102 Second power receiving point

Claims (9)

A first power receiving point connected to an AC commercial power system, and a first power grid to which power of the commercial power system is supplied from the first power receiving point.
It has a second power receiving point connected to the AC commercial power system and a second power network to which power of the commercial power system is supplied from the second power receiving point.
The first power grid has a different peak demand for power from the second power grid.
A power network in which the first power network and the second power network are interconnected by a DC line so that power can be supplied between the first power network and the second power network. The power network according to claim 1, wherein at least one of the first power grid and the second power network has a power generation device that generates power using renewable energy. The amount of power generated per unit time of the power generation device that generates power using the renewable energy of the first power network is the amount of power generated per unit time of the power generation device that generates power using the renewable energy of the second power network. The power network according to claim 2, which is different from the above. The power network according to any one of claims 1 to 3, wherein at least one of the first power network and the second power network has a stationary power storage device. The power network according to claim 4, wherein the charging capacity of the stationary power storage device of the first power grid is different from the charging capacity of the stationary power storage device of the second power grid. The first power grid inputs and outputs the power of the device constituting the first power network based on the own end voltage, and the second power network constitutes the second power network based on the own end voltage. The power network according to any one of claims 1 to 5, wherein the power of the device is input / output. Claim 1 in which the first power converter of the first power grid is connected to the first power receiving point, and the second power converter of the second power grid is connected to the second receiving point. The power network according to any one of 6 to 6. The power network according to any one of claims 1 to 7, wherein a DC / DC converter is provided on the DC line. The voltage of the DC line is boosted above the voltage of the first power network by the first power network side DC / DC converter provided between the first power network and the DC line, and the voltage of the second power network is increased. The power network according to any one of claims 1 to 7, wherein the voltage is higher than the voltage of the second power grid by a second power grid side DC / DC converter provided between the DC line and the DC line.

Images