JP2020099133A - Distributed power supply system - Google Patents

Abstract

To provide a distributed power supply system in which economical benefit is larger when power selling to an electric power system is made while reducing dealing of electric power with the electric power system.SOLUTION: In a distributed power supply system, when an operation of a charging and discharging part 22 is controlled in a surplus power handling mode, a prescribed first upper limit level is set to an upper limit charging level in a first time zone in which power generation by a first power generation device PV is relatively increased during a day to control charging by a charging and discharging part 22. A prescribed second upper limit level smaller than the first upper limit level is set to the upper limit charging level to control the charging by the charging and discharging part 22, in a second time zone in which the power generation of the first power generation device PV is relatively decreased during a day.SELECTED DRAWING: Figure 1

Description

The present invention relates to an AC line connected to an electric power system, a first power generation device connected to the AC line, a second power generation device connected to the AC line, and an AC line connected to the AC line. A charging/discharging unit including a storage battery for charging/discharging electric power, and a predetermined upper limit charging level as an upper limit of the charging level of the charging/discharging unit and a predetermined lower limit charging level as a lower limit of the charging level of the charging/discharging unit. The present invention relates to a distributed power supply system including a charging/discharging device having a charging/discharging control unit for controlling charging/discharging, and a power consuming device connected to an AC line.

Patent Document 1 describes a distributed power supply system including a solar power generation device and a charging/discharging device. This distributed power supply system describes an example in which the charging/discharging device operates in an operation mode called a green mode. In this green mode, when the total power consumption by the load is larger than the power generated by the photovoltaic power generator, that is, when the power shortage occurs, the charging/discharging device discharges the power corresponding to the power shortage. On the other hand, when surplus power that is not used by the load is generated from the power generated by the solar power generation device, the surplus power is charged by the charging/discharging device. However, when the charging/discharging device is already fully charged, the surplus power is sold to the power system. As described above, in the green mode, the charging/discharging device operates so as to reduce the trading of electric power between the distributed power supply system and the electric power system.

Note that Patent Document 1 does not describe a distributed power supply system in which a plurality of power generators are installed in addition to the charging/discharging device.

JP, 2005-159726, A

Patent Document 1 describes an example in which surplus power generated by a solar power generation device is sold, but in the case of a distributed power generation system in which a power generation device different from the solar power generation device is additionally installed, It is also assumed that the unit price of power sold to the power grid will differ for each power generator. In that case, the surplus power sold to the power grid may be generated by a power generator having a high power sale unit price, or may be generated by a power generator having a low power sale unit price. Therefore, even if the charging/discharging device is operated in the green mode as described above, it is preferable that the charging/discharging device can perform control so that electric power having a low unit selling price is charged as much as possible. That is, it is preferable that a sufficient charging margin be ensured in the charging/discharging unit of the charging/discharging device before the time when the generated power of the power generating device having a low power sale unit price becomes large.

The present invention has been made in view of the above problems, and an object thereof is to provide an economical merit when selling power to a power system while reducing the sale and purchase of power to and from the power system. The point is to provide a distributed power supply system in which the power consumption becomes large.

The characteristic configuration of the distributed power supply system according to the present invention for achieving the above object is that an AC line connected to a power system, a first power generator connected to the AC line, and the AC line are connected. A second power generator and a charging/discharging unit including a storage battery connected to the AC line and charging/discharging electric power with the AC line, and a predetermined upper limit charging level to an upper limit of the charging level of the charging/discharging unit. And a charging/discharging device having a charging/discharging control unit for controlling charging/discharging by the charging/discharging unit with a predetermined lower limit charging level being the lower limit of the charging level of the charging/discharging unit, and a power consuming device connected to the AC line. Is a distributed power system,
A first power sale unit price when the generated power of the first power generator is sold to the power system is lower than a second power sale unit price when the power generated by the second power generator is sold to the power system. Is set low,
The charge and discharge control unit of the charge and discharge device,
When the total generated power, which is the sum of the generated power of the first power generation device and the generated power of the second power generation device, is equal to or more than the power consumption of the power consumption device in a surplus power generation state, the charging level of the charging/discharging unit Until the upper limit charging level is reached, the surplus power coping mode that aims to charge the charging/discharging unit from the AC line with power equivalent to surplus power that can be derived by subtracting the consumed power from the total generated power To control the operation of the charging/discharging section,
In the case of the insufficient power generation state in which the total generated power is smaller than the consumed power, until the charge level of the charging/discharging unit reaches the lower limit charge level, the total generated power is subtracted from the consumed power to obtain a deficit. Controlling the operation of the charging/discharging unit in a power shortage coping mode aiming to discharge the corresponding power from the charging/discharging unit to the AC line;
The unprocessed surplus power that cannot be charged by the charging/discharging unit in the surplus power generation state is supplied to the power system based on the first power sale unit price and the second power sale unit price. Power is sold at the power sale price,
The unprocessed insufficient power that could not be covered by the discharge of the charging/discharging unit in the case of the insufficient power generation state is purchased from the power system at a predetermined power purchase rate,
When controlling the operation of the charging/discharging unit in the surplus power handling mode, a predetermined first upper limit level is set in the first time zone during which the generated power of the first power generation device becomes relatively large in one day. The upper limit charge level is set to control charging by the charging/discharging unit, and in the second time zone during which the generated power of the first power generation device becomes relatively small in one day, the charge amount is higher than the first upper limit level. The point is that a small second predetermined upper limit level is set to the upper limit charge level to control charging by the charging/discharging unit.
Here, at least one of the first power generator and the second power generator may be a device that uses natural energy to generate power.

According to the above characteristic configuration, the charging/discharging device charges the surplus power as much as possible by the surplus power coping mode when the surplus power occurs, and when the surplus power occurs, the surplus power is controlled by the shortage power coping mode. Discharge as much as you can. In this way, by charging and discharging the charging/discharging device, the amount of power sold to/from the power system is reduced, and the power generated by the first power generation device and the second power generation device of the distributed power supply system itself is reduced. It is effectively used by its own power consumption device.

In addition, when the charge/discharge control unit controls the operation of the charge/discharge unit in the surplus power handling mode, the charge/discharge control unit does not operate in a predetermined period during the first time period during which the generated power of the first power generation device is relatively large. The first upper limit level is set to the upper limit charge level to control the charging by the charging/discharging unit, and the first upper limit level is set in the second time zone during which the generated power of the first power generation device becomes relatively small. A predetermined second upper limit level smaller than the above is set as the upper limit charge level to control charging by the charging/discharging unit. That is, since the upper limit charge level is set relatively low in the second time zone, in the first time zone in which the upper limit charge level is subsequently set relatively high, there is a margin for charging a large amount of electric power. To do. Further, in the first time zone, there is a high possibility that surplus power with a low power sale unit price to the power system will become large. Therefore, in the first time period when there is a margin for charging a large amount of electric power, the generated power of the first power generation device having a low power sale unit price is likely to be charged by the charging/discharging device. In other words, it is possible to avoid as much as possible a situation in which the power with a low unit selling price has to be sold as surplus power to the power system.
Therefore, it is possible to provide a distributed power supply system in which the economic merit is large when the power is sold to the electric power system while reducing the trading of electric power with the electric power system.

Still another characteristic configuration of the distributed power supply system according to the present invention is that the first power generation device is a solar power generation device, and the first time zone and the second time zone are set according to sunrise time and sunset time. There is a point to be.

According to the above characteristic configuration, the first time period in which the power generated by the solar power generation device is relatively large and the second time period in which the power generated by the solar power generation device is relatively low are defined as sunrise time and date. It can be set appropriately according to the arrival time of.

Still another characteristic configuration of the distributed power supply system according to the present invention is the time period in which the power generation power of the first power generator is equal to or higher than a set power generation power or is predicted to be equal to or higher than the set power generation power in the first time zone. The second time period includes a time period, and the second time period includes a time period in which the generated power of the first power generator is smaller than the set generated power or smaller than the set generated power.

According to the above characteristic configuration, the generated power of the first power generation device is relatively set to a time period in which the generated power of the first power generation device is actually set power generation power or more or a time period predicted to be set power generation power or more. It can be appropriately set as the larger first time zone. In addition, a time zone in which the generated power of the first power generator is actually smaller than the set generated power or smaller than the set generated power is set as a second time zone in which the generated power of the first power generator is relatively small. Can be set appropriately.

Still another characteristic configuration of the distributed power supply system according to the present invention is that the charging/discharging control unit of the charging/discharging device makes a predetermined determination of the second upper limit level to be set in the second time zone coming next. It is configured to perform an upper limit level determination process that determines the value that minimizes the power cost in a period,
In the upper limit level determination process,
Reference generated power data and the power consumption of the power consuming device that shows a temporal change in the total generated power that is the sum of the generated power of the first power generator and the generated power of the second power generator in the determination period. Of the reference power consumption data that shows the change over time is specified to specify the period in which the power shortage occurs and the period in which the surplus power occurs,
The electric power cost in the determination period, the electric power purchase fee when the electric power is bought from the electric power system while controlling the operation of the charging/discharging unit in the electric power shortage handling mode in response to the electric power shortage occurrence state. And deriving based on the power sale charge when selling power to the power system while controlling the operation of the charging/discharging unit in the surplus power handling mode according to the surplus power generation state. is there.
Here, the reference generated power data is created using data that shows a temporal change in the total generated power, which is the sum of the generated power of the first power generator and the generated power of the second power generator in the past. The reference power consumption data may be created using data that shows a temporal change in the power consumption of the power consumption device in the past.

According to the above characteristic configuration, the reference generated power data of the total generated power, which is the sum of the generated power of the first power generator and the generated power of the second power generator in the determination period, and the reference power consumption of the power consumption device. By referring to the data, it is possible to set the second upper limit level that reduces the power cost.

Still another characteristic configuration of the distributed power supply system according to the present invention is that the charging/discharging control unit of the charging/discharging device has a charging level of the charging/discharging unit at the end of the determination period in the upper limit level determination process. However, if the charging level of the charging/discharging unit at the start of the determination period is increased by a predetermined increase amount, the selling price of the charge assuming that the power corresponding to the increase amount is sold to the power grid is If the charge level of the charging/discharging unit at the end of the determination period is included in the electricity charge and becomes smaller than the charge level of the charging/discharging unit at the start of the determination period by a predetermined decrease amount, the decrease The point is to include the charge in the case where it is assumed that the power corresponding to the minute is purchased from the power system.

According to the above characteristic configuration, in the upper limit level determination process, when the power stored in the charging/discharging unit from the beginning changes between the start time and the end time of the determination period, the power of the change is calculated. Tariffs are included in the calculation of power costs. As a result, the calculation of the power cost in the upper limit level determination process will be performed in more detail.

It is a figure which shows the structure of a distributed power supply system. In this example, the charging/discharging device is operating in the surplus power coping mode. This is an example of the case where the charging/discharging device is operating in the power shortage coping mode. It is a graph which shows transition of electric power and charge level. It is a table explaining an example of an upper limit level determination process. It is a table explaining an example of an upper limit level determination process.

A distributed power supply system according to an embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing a configuration of a distributed power supply system. As shown in the figure, the distributed power supply system is connected to an AC line 2 connected to the power system 1, a photovoltaic power generator PV as a first power generator connected to the AC line 2, and an AC line 2. A fuel cell device 10 as a second power generator and a charging/discharging device 20 connected to the AC line 2 are provided, and the power consumption device 3 is connected to the AC line 2.

[Solar power generator PV]
The solar power generation device PV as the first power generation device includes an element (not shown) that directly converts light energy of incident light (sunlight) into electric energy, and power generated by the element to a desired voltage and frequency. , And a power converter (not shown) for converting into phase power and outputting to the AC line 2.

The power generated by the photovoltaic power generator PV can be sold to the power grid 1. The power selling unit price (first power selling unit price) when the generated power of the photovoltaic power generator PV is sold to the power system 1 is set in advance, and is stored in, for example, a storage device (not shown) of the charging/discharging device 20. Remembered The unit price of power sale may be sequentially updated to a value acquired through internet communication or the like.

[Fuel Cell Device 10]
The fuel cell device 10 as the second power generation device has a fuel cell unit 12 as a power generation unit and a fuel cell control unit 11 as a power generation control unit that controls the operation of the fuel cell unit 12. The fuel cell unit 12 includes a fuel cell 12 a and a power conversion unit 12 b for converting electric power generated in the fuel cell 12 a into electric power having a desired voltage, frequency, and phase and outputting the electric power to the AC line 2.

The fuel cell 12a can be realized by using, for example, a solid oxide fuel cell (SOFC). Alternatively, the fuel cell 12a may be realized by using another type of fuel cell 12a such as a polymer electrolyte fuel cell (PEFC). Although not shown, the fuel cell unit 12 may include a fuel reformer that produces hydrogen or the like as a fuel gas to be supplied to the anode of the fuel cell 12a by a reforming process. Then, the fuel cell control unit 11 controls the operation start, operation stop, output state, etc. of the fuel cell 12a. Further, the fuel cell control unit 11 controls the power conversion operation by the power conversion unit 12b.

The fuel cell control unit 11 of the fuel cell device 10 controls the operation of the fuel cell unit 12 so as to output constant generated power such as rated generated power to the AC line 2.
Alternatively, the fuel cell control unit 11 of the fuel cell device 10 causes the generated power supplied from the fuel cell unit 12 to the AC line 2 to follow the power consumption of the power consuming device 3 (for example, so that both are equal). The operation of the battery unit 12 may be controlled.

The power generated by the fuel cell device 10 can be sold to the power grid 1. The power selling unit price (second power selling unit price) when selling the generated power of the fuel cell device 10 to the power system 1 is set in advance, and is stored in, for example, a storage device (not shown) of the charging/discharging device 20. Has been done. The unit price of power sale may be sequentially updated to a value acquired through internet communication or the like. In the present embodiment, the first selling price when the generated power of the photovoltaic power generator PV is sold to the power system 1 is the second selling price when the generated power of the fuel cell device 10 is sold to the power system 1. It is set lower than the electricity unit price. Therefore, in the present embodiment, it is more cost-effective to sell the generated power of the fuel cell device 10 to the power system 1 than to sell the generated power of the photovoltaic power generator PV to the power system 1.

[Charging/Discharging Device 20]
The charging/discharging device 20 includes a charging/discharging unit 22 including a storage battery 22a for charging/discharging electric power to/from the AC line 2 and a charging/discharging control unit 21 that controls operations of the charging/discharging unit 22. In addition, in the charging/discharging unit 22 of the present embodiment, the storage battery 22a is connected to the AC line 2 via the power conversion unit 22b. As a result, in the charging/discharging unit 22, the electric power stored in the storage battery 22a can be converted into electric power having a desired voltage, frequency, and phase and output to the AC line 2. In this case, the charge/discharge control unit 21 sets the predetermined upper limit charge level as the upper limit of the charge level of the charge/discharge unit 22 and sets the predetermined lower limit charge level as the lower limit of the charge level of the charge/discharge unit 22 to charge/discharge the charge/discharge unit 22. To control. The storage battery 22a can be configured using, for example, a secondary battery such as a lithium ion battery. The charge/discharge control unit 21 controls the operation of the power conversion unit 22b to control the discharge power from the charge/discharge unit 22 to the AC line 2 and the charge power from the AC line 2 to the charge/discharge unit 22. To do.

Information about the electric power measured by the electric power measuring device 5 is transmitted to the charge/discharge control unit 21. In the present embodiment, the power meter 5 is provided on the upstream side (on the side of the power system 1) of the location where the photovoltaic power generator PV is connected, and measures the power supplied from the power system 1 to the AC line 2. measure. If the power measured by the power meter 5 is a positive value, the distributed power supply system is buying power from the power grid 1, and if the power measured by the power meter 5 is a negative value, The distributed power supply system sells power to the power grid 1. The electric power measuring device 5 is configured by using, for example, a current transformer (current transformer for measuring instrument) used for detecting the electric current value of the electric power in the AC line 2, and has a predetermined voltage value (for example, 100V, 200V, etc.). The power value on the AC line 2 can be derived from the product. The power meter 5 may transmit only the current value of the power on the AC line 2 to the charge/discharge control unit 21, and the charge/discharge control unit 21 may derive the power value. Then, the charge/discharge control unit 21 refers to the measurement result of the power meter 5 and the charge/discharge control unit 21 controls the charge/discharge of the charge/discharge unit 22.

When the charging/discharging device 20 is discharging power to the AC line 2, the power measured by the power meter 5 is the power consumption that the power consuming device 3 receives from the AC line 2, and the solar power generation device PV is the AC line 2 To a value obtained by subtracting the sum of the generated power supplied to the AC line 2, the generated power supplied to the AC line 2 by the fuel cell device 10, and the discharge power supplied to the AC line 2 by the charging/discharging device 20. On the other hand, when the charging/discharging device 20 is charging the power of the AC line 2, the power measured by the power meter 5 is the power consumption that the power consuming device 3 receives from the AC line 2 and the charging/discharging device 20 uses the AC power. From the sum of the charging power charged from the line 2 and the sum of the generated power supplied by the photovoltaic power generation device PV to the AC line 2 and the generated power supplied by the fuel cell device 10 to the AC line 2. It will be the subtracted value.

In the present embodiment, the charging/discharging control unit 21 of the charging/discharging device 20 performs control so that the trading of power between the distributed power supply system and the power grid 1 is minimized. Specifically, the charging/discharging control unit 21 of the charging/discharging device 20 is the sum of the generated power of the photovoltaic power generation device PV (first power generation device) and the generated power of the fuel cell device 10 (second power generation device). In the case of the surplus power generation state in which the total generated power is equal to or more than the power consumption of the power consumption device 3, the surplus power that can be derived by subtracting the power consumption from the total generated power until the charging level of the charging/discharging unit 22 reaches the upper limit charging level. The operation of the charging/discharging unit 22 is controlled in the surplus power coping mode in which the charging/discharging unit 22 is charged with the electric power corresponding to In the surplus power handling mode, the surplus power is charged in the charging/discharging unit 22 as much as possible.

On the other hand, in the case of the insufficient power generation state in which the total generated power is smaller than the consumed power, it corresponds to the insufficient power that can be derived by subtracting the total generated power from the consumed power until the charging level of the charging/discharging unit 22 reaches the lower limit charging level. The operation of the charging/discharging unit 22 is controlled in the power shortage coping mode that aims to discharge the electric power to be discharged from the charging/discharging unit 22 to the AC line 2. In this power shortage handling mode, the charging/discharging unit 22 discharges so as to cover the power shortage as much as possible.

FIG. 2 is an example of the case where the charging/discharging device 20 is operating in the surplus power coping mode. In addition, the electric power value described in the drawing is a value described for the purpose of illustration. As shown in the figure, the total generated power (1.7 kW), which is the sum of the generated power (1 kW) of the photovoltaic power generation device PV and the generated power (0.7 kW) of the fuel cell device 10, is consumed by the power consumption device 3. It is in a surplus power generation state of power (0.5 kW) or more. If the charging/discharging device 20 is neither charging nor discharging, 1.2 kW of electric power is sold to the power grid 1, but in the example shown in FIG. 2, the charging/discharging device 20 supplies 1.1 kW of electric power. Charging. In this way, the charge/discharge control unit 21 of the charge/discharge device 20 sets the charge level of the charge/discharge unit 22 to the upper limit charge level so that the electric power measured by the electric power measuring device 5 (power sales power) becomes as small as possible. Up to the surplus power, the charging/discharging unit 22 is charged from the AC line 2. Even when the charging/discharging unit 22 is charged with electric power corresponding to the surplus electric power, when the charging level of the charging/discharging unit 22 reaches the upper limit charging level, the charging cannot be performed any more and the charging is not performed. When the electric power to be charged reaches the upper limit value of the charging power of the charging/discharging unit 22 (for example, the capacity of the power conversion unit 22b), no more electric power can be charged. As the charging/discharging unit 22 is charged, in the example shown in FIG. 2, only the unprocessed surplus power (0.1 kW) that could not be charged by the charging/discharging unit 22 is sold to the power grid 1. ..

FIG. 3 is an example of the case where the charging/discharging device 20 is operating in the power shortage coping mode. In addition, the electric power value described in the drawing is a value described for the purpose of illustration. As illustrated, the total generated power (0.7 kW), which is the sum of the generated power (0 kW) of the solar power generation device PV and the generated power (0.7 kW) of the fuel cell device 10, is consumed by the power consumption device 3. It is in a power shortage state that is smaller than the power (2 kW). If the charging/discharging device 20 is neither charging nor discharging, 1.3 kW of power is purchased from the power grid 1, but in the example shown in FIG. 3, the charging/discharging device 20 discharges 1.3 kW of power. doing. In this way, the charge/discharge control unit 21 of the charge/discharge device 20 sets the charge level of the charge/discharge unit 22 to the lower limit charge level so that the power measured by the power meter 5 (power purchase power) is as small as possible. Up to, the power corresponding to the insufficient power is discharged from the charging/discharging unit 22 to the AC line 2. Even when the target is to discharge the power corresponding to the insufficient power from the charging/discharging unit 22, when the charging level of the charging/discharging unit 22 reaches the lower limit charging level, further discharging cannot be performed, and the discharging is performed. When the generated power reaches the upper limit value of the discharge power of the charging/discharging unit 22 (for example, the capacity of the power conversion unit 22b), further power cannot be discharged. In the example shown in FIG. 3, the electric power purchased from the electric power system 1 is zero due to the discharging from the charging/discharging unit 22. The power purchase unit price for purchasing power from the power grid 1 is set in advance and is stored in, for example, a storage device (not shown) of the charging/discharging device 20. The power purchase unit price may be sequentially updated to a value acquired by internet communication or the like.

In the charging/discharging device 20 of the present embodiment, the charging/discharging control unit 21 controls charging by the charging/discharging unit 22 with a predetermined upper limit charging level as the upper limit of the charging level of the charging/discharging unit 22, but the upper limit charging level is 1 It is a variable value that is set for each of multiple time zones during the day. Specifically, when the charge/discharge control unit 21 controls the operation of the charge/discharge unit 22 in the surplus power coping mode, the generated power of the photovoltaic power generation device PV (first power generation device) in one day is relative. In the first time zone, which is increased significantly, the predetermined first upper limit level is set to the upper limit charge level to control the charging by the charge/discharge unit 22 so that the generated power of the photovoltaic power generation device PV is relatively high in one day. In the second time zone in which the charging/discharging unit 22 is set to the upper limit charge level, a predetermined second upper limit level smaller than the first upper limit level is set as the upper limit charge level to control the charging by the charging/discharging unit 22.

FIG. 4 is a graph showing changes in electric power and charge level. Specifically, FIG. 4A is a graph of power consumption of the power consumption device 3. FIG. 4B is a graph of the generated power of the photovoltaic power generator PV, the generated power of the fuel cell device 10, and the total generated power thereof. FIG. 4C is a graph of surplus power and insufficient power. In these graphs, the transition of the average power for one hour is shown by a line graph. For example, in FIG. 4A, the average power consumption at the 7 o'clock time is shown as the power consumption at the 7 o'clock time. Moreover, FIG.4(d) is a graph of a charge level. In this graph, the transition of the charge level of the storage battery 22a at the end of one hour is shown by a line graph. For example, the charge level at the end of the 7 o'clock time is shown as the charge level at 7 o'clock in FIG. 4(d).

As shown in FIG. 4( b ), the power generated by the fuel cell device 10 is constantly controlled at 0.7 kW. The power generated by the solar power generation device PV is generated from the 6 o'clock time to the 17:00 o'clock time. As described above, since the photovoltaic power generation device PV is a device that uses natural energy to generate power, the magnitude of generated power changes according to the natural energy (irradiation intensity of sunlight), that is, the generated power. The size cannot be freely controlled, and there are a time period in which the generated power is relatively large and a time period in which the generated power is relatively small. In the present embodiment, the time period in which the generated power of the photovoltaic power generator PV is relatively large is the first time period, and the time period in which the generated power is relatively small is the second time period. In the example shown in FIG. 4, the period from 6:00 to 18:00 is the first time period, and the period from 18:00 to 6:00 on the next day is the second time period.

In the case of the solar power generation device PV, since the generated power changes according to the received sunlight energy, the first time zone and the second time zone can be set according to the sunrise time and the sunset time. For example, the charging/discharging control unit 21 of the charging/discharging device 20 refers to the calendar information, sets the time period from the sunrise time to the sunset time to the first time zone, and sets the second time from the sunset time to the sunrise time. Can be set to the obi. That is, since the sunset time changes to the sunrise time in a year, the time period in which the power generated by the photovoltaic power generation device PV is relatively large and the time period in which the power generation amount is relatively small are 1 year. Although it changes in the middle, the first time zone and the second time zone can be appropriately set by referring to the calendar information.

Alternatively, the charging/discharging control unit 21 of the charging/discharging device 20 may set the first time period to include a time period in which the power generation of the photovoltaic power generation device PV becomes equal to or higher than the set power generation power or is predicted to be higher than the set power generation power. The second time zone may be set so as to include a time zone in which the generated power of the photovoltaic power generation device PV becomes smaller than the set generated power or becomes smaller than the set generated power.

For example, when the charging/discharging control unit 21 of the charging/discharging device 20 can obtain information on the generated power of the photovoltaic power generation device PV, data or the like that shows a past temporal change in the generated power of the photovoltaic power generation device PV. Referring to (for example, power generation data of the solar power generation device PV for the last few days), the time period (first time period) in which the power generation power of the solar power generation device PV is predicted to be equal to or higher than the set power generation power, and The time zone (second time zone) predicted to be smaller than the set generated power can be specified in advance.

In addition, when the charge/discharge control unit 21 of the charge/discharge device 20 can obtain information about the generated power of the photovoltaic power generator PV, if the current generated power of the photovoltaic power generator PV is referred to, the photovoltaic power generation is performed. It is possible to determine whether the generated power of the device PV is equal to or higher than the set generated power. Therefore, the charging/discharging control unit 21 of the charging/discharging device 20 refers to the current power generation of the photovoltaic power generation device PV, and if the power generation is equal to or higher than the set power generation, the current time is the first time zone. If it is determined that the generated power is smaller than the set generated power, it can be determined that the current time is the second time zone.

As shown in FIG. 4C, insufficient power is generated in 6 hours from 18:00 to 0:00. In other words, the total generated power that is the sum of the generated power of the photovoltaic power generation device PV and the generated power of the fuel cell device 10 is smaller than the power consumption of the power consumption device 3 during the six hours, in a power shortage state. On the other hand, surplus power is generated in 18 hours from 0:00 to 18:00. That is, the 18 hours is in a surplus power generation state in which the total generated power, which is the sum of the generated power of the photovoltaic power generation device PV and the generated power of the fuel cell device 10, is equal to or more than the power consumption of the power consumption device 3. ..

Even if surplus power as shown in FIG. 4C is generated, not all of it can be charged by the charging/discharging device 20. For example, if the charging level of the charging/discharging unit 22 of the charging/discharging device 20 reaches the upper limit charging level, further charging cannot be performed. Alternatively, if the electric power to be charged reaches the upper limit value of the electric power to be charged by the charging/discharging unit 22 (for example, the capacity of the electric power conversion unit 22b), the electric power cannot be charged further. In this case, the unprocessed surplus power that could not be charged by the charging/discharging unit 22 in the surplus power generation state is supplied to the power system 1 by a predetermined amount determined based on the first power sale unit price and the second power sale unit price. Power is sold at the power sale charge (unit price x electric energy).

Similarly, even if the power shortage as shown in FIG. 4C occurs, not all of it can be covered by the discharge power of the charging/discharging device 20. For example, if the charging level of the charging/discharging unit 22 of the charging/discharging device 20 reaches the lower limit charging level, further discharging cannot be performed. Alternatively, if the discharged power reaches the upper limit value of the discharge power of the charging/discharging unit 22 (for example, the capacity of the power conversion unit 22b), it is impossible to discharge more power. In that case, the unprocessed insufficient power that cannot be covered by the discharge of the charging/discharging unit 22 in the case of the insufficient power generation state is purchased from the power system 1 at a predetermined power purchase charge (unit price×electric energy). ..

As described above, when the charging level of the charging/discharging unit 22 of the charging/discharging device 20 reaches the upper limit charging level, the unprocessed surplus power generated thereafter must be sold to the power grid 1, Considering that if the charging level of the charging/discharging unit 22 of 20 reaches the lower limit charging level, the unprocessed insufficient power generated thereafter must be purchased from the power system 1, in the case of selling power to the power system 1. Therefore, it is preferable to be able to sell electricity with a high unit price. For example, the charging/discharging unit 22 of the charging/discharging device 20 is provided before the time when the power generation of the power generating device having the low selling power unit price becomes large so that the charging/discharging device 20 can charge the power having the low selling price. It is preferable that a sufficient charging margin be secured.

In the present embodiment, since the unit power selling price of the photovoltaic power generator PV is set to be lower than the unit power selling price of the fuel cell device 10, the power generation amount of the photovoltaic power generator PV becomes relatively small in the second time period. Then, charging of the charging/discharging unit 22 is suppressed so that the charging/discharging unit 22 can be charged with electric power having a low unit selling price as much as possible during the first time period when the generated power of the photovoltaic power generator PV is relatively large. Is preferred. That is, when the charge/discharge control unit 21 of the charge/discharge device 20 controls the operation of the charge/discharge unit 22 in the surplus power coping mode, the generated power of the photovoltaic power generation device PV (first power generation device) during one day. In the first time zone in which is relatively large, the predetermined first upper limit level is set to the upper limit charge level to control the charging by the charging/discharging unit 22, and the generated power of the photovoltaic power generator PV in one day In the relatively small second time period, a predetermined second upper limit level smaller than the first upper limit level is set as the upper limit charge level to control charging by the charge/discharge unit 22. Therefore, the charging/discharging control unit 21 of the charging/discharging device 20 determines the upper limit level that determines the second upper limit level to be set in the second time zone that comes next to the value that minimizes the power cost in the predetermined determination period. Perform processing in advance.

In the example shown in FIG. 4D, the first upper limit level is set to 5 kWh in the first time zone, and the second upper limit level is set to 2 kWh in the second time zone. That is, since the upper limit charge level is set relatively low in the second time zone, in the first time zone in which the upper limit charge level is subsequently set relatively high, there is a margin for charging a large amount of electric power. To do. Further, in the first time zone, there is a high possibility that surplus power with a low power sale unit price to the power system 1 will become large. Therefore, in the first time period when there is a margin for charging a large amount of power, the generated power of the solar power generation device PV having a low power sale unit price is likely to be charged by the charging/discharging device 20. In other words, it is possible to avoid as much as possible a situation in which the power with a low power sale unit price has to be sold to the power system 1 as surplus power.

To give a specific example, in the upper limit level determination process, the charge/discharge control unit 21 of the charge/discharge device 20 generates power from the photovoltaic power generation device PV (first power generation device) and the fuel cell device 10( in the predetermined determination period. Power deficit with reference to the reference generated power data indicating the temporal change of the total generated power that is the sum of the generated power of the second power generator) and the reference power consumption data indicating the temporal change of the power consumption of the power consumption device 3. The period during which the power is generated and the period during which the surplus power is generated are specified. For example, the reference generated power data is created by using data that shows a temporal change in the total generated power, which is the sum of the generated power of the photovoltaic power generation device PV and the generated power of the fuel cell device 10 in the past. The data is created using data that shows the temporal change in the power consumption of the power consumption device 3 in the past. When the charge/discharge control unit 21 buys power from the power system 1 while controlling the operation of the charge/discharge unit 22 in the power shortage coping mode according to the power cost during the determination period in response to the power shortage occurrence state. It is derived on the basis of the power purchase price and the power sale price when the power is sold to the power system 1 while controlling the operation of the charging/discharging unit 22 in the surplus power handling mode according to the surplus power generation state.

5 and 6 are tables illustrating an example of the upper limit level determination process. This table shows an example of deriving the power cost when the determination period is two days and the second upper limit level, which is the upper limit charge level set between time 18:00 and time 6:00, is 2 (kWh). .. In this case, since the current time is 18:00, the power cost in the determination period of two days (total 48 hours) from 18:00 two days ago to 18:00 on the day is derived. That is, the reference generated power data in this example is the time of the total generated power that is the sum of the generated power of the photovoltaic power generation device PV and the generated power of the fuel cell device 10 in the past two days from two days before to the current day. The reference power consumption data is created using data that shows a temporal change in the power consumption of the power consumption device 3 in the past two days from two days before to the present day. Further, in this example, the first time period in which the generated power of the photovoltaic power generator PV is relatively large is set between 6:00 and 18:00, and the generated power of the photovoltaic power generator PV is relatively reduced in the second time period. The time zone is set between 18:00 and 6:00. Further, in this example, when the generated power of the photovoltaic power generation device PV is sold to the power system 1, the unit selling price is 3 yen/kWh, and the generated power of the fuel cell device 10 is sold to the power system 1. The power selling unit price is 9.3 yen/kWh, and the power purchasing unit price when purchasing power from the power system 1 is 22 yen/kWh.

Reference generated power data and consumption of the power consumption device 3 showing the temporal change of the total generated power, which is the sum of the generated power of the photovoltaic power generator PV and the generated power of the fuel cell device 10, as shown in FIGS. 5 and 6. By referring to the reference power consumption data that shows the temporal change in power, it is possible to specify the period in which the power shortage occurs and the period in which the surplus power occurs. Then, the electric power cost in the determination period of two days is purchased when the electric power is bought from the electric power system 1 while controlling the operation of the charging/discharging unit 22 in the electric power shortage coping mode according to the electric power shortage occurrence state. The charge can be derived based on the charge and the power sale charge when the power is sold to the power system 1 while controlling the operation of the charging/discharging unit 22 in the surplus power handling mode according to the surplus power generation state.

In the example shown in FIG. 5 and FIG. 6, of the surplus power generated between 11:00 and 17:00 of the day before, the power that could not be charged by the charging/discharging device 20 is transferred to the power system 1. Is sold. In this example, it is assumed that the surplus of the generated power of the solar power generation device PV having a low power sale unit price is sold to the power system 1 at 3 yen/kWh. In addition, in FIGS. 5 and 6, the power cost in the case of selling power is shown by a negative numerical value. As a result, the total of the electric power costs in the determination period of two days (total 48 hours) from 18:00 two days ago to 18:00 on the day is “−14.1 yen”. By calculating the power cost in this way by changing the value of the second upper limit level set in the second time zone (time 18:00 to time 6:00), the second upper limit when the power cost becomes the smallest You can specify the level value.

The following Table 1 shows the second upper limit levels set in the second time period from 18:00 to 6:00 as 0 (kWh), 1 (kWh), 2 (kWh), 3 (kWh), 4 ( It is the result of the calculated value of the electric power cost in the determination period when it is set to (kWh) and 5 (kWh).

As shown in Table 1, the calculated value of the power cost in the determination period is the smallest when the second upper limit level is set to 0 (kWh). Therefore, in the upper limit level setting process, the charging/discharging control unit 21 of the charging/discharging device 20 sets the second upper limit level set in the second coming time zone to 0 (kWh).

<Another embodiment>
<1>
In the above embodiment, the configuration of the distributed power supply system of the present invention has been described with reference to specific examples, but the configuration can be changed as appropriate.
For example, although the fuel cell device 10 has been described as an example of the second power generation device of the present invention, various types of power generation devices such as a power generation device including an engine and a generator driven by the engine can be used. A power generator can be used.
Further, the configurations of the fuel cell device 10 and the charging/discharging device 20 are not limited to those shown in the drawings, and can be changed as appropriate.
Furthermore, in the above embodiment, the case where the first power generation device is the solar power generation device PV and the second power generation device is the fuel cell device 10 has been described, but the types of the first power generation device and the second power generation device are different. It can be set appropriately. Although the solar power generation device has been exemplified as a device for generating power using natural energy, a device for generating power using other natural energy such as tidal force or wind power can also be adopted.

<2>
In the above embodiment, the charge level (5 kWh) of the charging/discharging unit 22 at the start of the determination period shown in FIGS. 5 and 6 is different from the charge level (3.6 kWh) at the end thereof. In this example, 1.4 kWh of the electric power stored in the charging/discharging unit 22 from the original is used, so that the charging level of the charging/discharging unit 22 at the end of the determination period is lower than the charging level at the start. Is also reduced by 1.4kWh. In other words, what should have been procured from the power grid 1 for 1.4 kWh and included in the calculation of the power cost was covered by the discharge from the charging/discharging unit 22 (that is, included in the calculation of the power cost). It could also be said. Therefore, when the charge level of the charging/discharging unit 22 changes between the start time and the end time of the determination period in the upper limit level determination process, the changed power is converted into a charge and included in the calculation of the power cost. It is preferable.

Therefore, in this another embodiment, the charge/discharge control unit 21 of the charge/discharge device 20 determines that the charge level of the charge/discharge unit 22 at the end of the determination period is the charge/discharge at the start of the determination period in the upper limit level determination process. If the charging level becomes higher than the charging level of the unit 22 by a predetermined increase amount, the charge assuming that the power corresponding to the increase amount is sold to the power system 1 is included in the power sale charge, and the charge at the end of the determination period is included. When the charging level of the charging/discharging unit 22 is smaller than the charging level of the charging/discharging unit 22 at the start of the determination period by a predetermined decrease amount, when it is assumed that electric power corresponding to the decrease amount is purchased from the power system 1. Included in the purchase price. In this case, information about the purchase price of electricity when purchasing power from the power system 1 is stored in, for example, a storage device (not shown) of the charging/discharging device 20. As described above, if 1.4 kWh of electric power is to be procured from the electric power system 1, if the unit price of electric power purchase is 22 yen/kWh, it is a charge when it is assumed that the electric power system 1 is purchased. 8 yen will be included in the electricity cost as a purchase price. In this way, when the electric power originally stored in the charging/discharging unit 22 changes between the start time and the end time of the determination period, the changed electric power charge is included in the calculation of the electric power cost. To be As a result, the calculation of the power cost in the upper limit level determination process will be performed in more detail.

<3>
In the above embodiment, the case where the determination period is two days has been illustrated, but the length of the determination period can be set appropriately.

<4>
In the above embodiment, the unit price of power sold to the power system 1 and the unit price of power purchased from the power system 1 and the numerical values of the first upper limit level and the second upper limit level have been described with specific numerical values. Is described for the purpose of illustration and can be changed as appropriate.

<5>
In the above-described embodiment, the reference generated power data is created using data that shows the temporal change of the past total generated power, and the reference power consumption data is created using data that shows the past time change of the consumed power. Although an example has been described, the reference generated power data and the reference power consumption data may be other data. For example, the reference generated power data is the total generated power that is the sum of the generated power of the photovoltaic power generation device PV (first power generation device) and the generated power of the fuel cell device 10 (second power generation device) during the determination period. The reference value power consumption data may be prediction value data that shows a temporal change, and the reference power consumption data may be prediction value data that shows a time change of the power consumption of the power consumption device 3 in the determination period.

<6>
The configurations disclosed in the above-described embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with the configurations disclosed in other embodiments as long as no contradiction arises, and are also disclosed in this specification. The embodiments are exemplifications, and the embodiments of the present invention are not limited thereto, and can be modified as appropriate without departing from the object of the present invention.

INDUSTRIAL APPLICABILITY The present invention can be used for a distributed power supply system in which economical merit is large when selling power to a power system while reducing the sales of power to and from the power system.

1 Power System 2 AC Line 3 Power Consumption Device 10 Fuel Cell Device (Second Generator)
11 Fuel Cell Control Section 12 Fuel Cell Section 12a Fuel Cell 12b Power Conversion Section 20 Charge/Discharge Device 21 Charge/Discharge Control Section 22 Charge/Discharge Section 22a Storage Battery 22b Power Conversion Section 5 Power Meter PV Solar Power Generation Device (First Generation Device)

Claims (7)

Between an AC line connected to the power system, a first power generator connected to the AC line, a second power generator connected to the AC line, and the AC line connected to the AC line. A charging/discharging unit including a storage battery that charges and discharges electric power, and a predetermined upper limit charging level as the upper limit of the charging level of the charging/discharging unit and a predetermined lower limit charging level as the lower limit of the charging level of the charging/discharging unit. A distributed power supply system comprising a charging/discharging device having a charging/discharging control unit for controlling charging/discharging by a discharging unit, wherein a power consumption device is connected to the AC line,
A first power sale unit price when the generated power of the first power generator is sold to the power system is lower than a second power sale unit price when the power generated by the second power generator is sold to the power system. Is set low,
The charge and discharge control unit of the charge and discharge device,
When the total generated power, which is the sum of the generated power of the first power generation device and the generated power of the second power generation device, is equal to or more than the power consumption of the power consumption device in a surplus power generation state, the charging level of the charging/discharging unit Until the upper limit charging level is reached, the surplus power coping mode that aims to charge the charging/discharging unit from the AC line with power equivalent to surplus power that can be derived by subtracting the consumed power from the total generated power To control the operation of the charging/discharging section,
In the case of the insufficient power generation state in which the total generated power is smaller than the consumed power, until the charge level of the charging/discharging unit reaches the lower limit charge level, the total generated power is subtracted from the consumed power to obtain a deficit. Controlling the operation of the charging/discharging unit in a power shortage coping mode aiming to discharge the corresponding power from the charging/discharging unit to the AC line;
The unprocessed surplus power that cannot be charged by the charging/discharging unit in the surplus power generation state is supplied to the power system based on the first power sale unit price and the second power sale unit price. Power is sold at the power sale rate,
In the case of the power shortage occurrence state, the unprocessed power shortage that could not be covered by the discharge of the charging/discharging unit is purchased from the power system at a predetermined power purchase charge,
When controlling the operation of the charging/discharging unit in the surplus power handling mode, a predetermined first upper limit level is set in the first time zone during which the generated power of the first power generator is relatively large in one day. The upper limit charge level is set to control charging by the charging/discharging unit, and in the second time zone during which the generated power of the first power generation device becomes relatively small in one day, the charge amount is higher than the first upper limit level. A distributed power supply system for controlling charging by the charging/discharging unit by setting a small second predetermined upper limit level to the upper limit charge level. The distributed power supply system according to claim 1, wherein at least one of the first power generation device and the second power generation device is a device that uses natural energy to generate power. The first power generator is a solar power generator,
The distributed power supply system according to claim 2, wherein the first time zone and the second time zone are set according to sunrise time and sunset time. The first time zone includes a time zone in which the generated power of the first power generator is equal to or greater than a set generated power or is equal to or greater than the set generated power,
The distributed power supply system according to claim 1 or 2, wherein the second time zone includes a time zone in which the generated power of the first power generator is predicted to be smaller than the set generated power or smaller than the set generated power. .. The charging/discharging control unit of the charging/discharging device determines an upper limit level that determines the second upper limit level set in the second time zone that arrives next to a value that minimizes the power cost in a predetermined determination period. Configured to do the processing in advance,
In the upper limit level determination process,
Reference generated power data and the power consumption of the power consuming device that shows a temporal change in the total generated power that is the sum of the generated power of the first power generator and the generated power of the second power generator in the determination period. Of the reference power consumption data that shows the change over time is specified to specify the period in which the power shortage occurs and the period in which the surplus power occurs,
The electric power cost in the determination period, the electric power purchase fee when the electric power is bought from the electric power system while controlling the operation of the charging/discharging unit in the electric power shortage handling mode in response to the electric power shortage occurrence state. And deriving based on the power sale charge when selling power to the power system while controlling the operation of the charging/discharging unit in the surplus power handling mode in response to the surplus power generation state. The distributed power supply system according to any one of claims 1 to 4. The charge and discharge control unit of the charge and discharge device, in the upper limit level determination process,
When the charging level of the charging/discharging unit at the end of the determination period becomes larger than the charging level of the charging/discharging unit at the start of the determination period by a predetermined increase amount, the power corresponding to the increase amount. Including the charge in the case of selling to the power system,
When the charge level of the charge/discharge unit at the end of the determination period is smaller than the charge level of the charge/discharge unit at the start of the determination period by a predetermined decrease amount, the power corresponding to the decrease amount. The distributed power supply system according to claim 5, wherein a charge when it is assumed that the power is purchased from the power system is included in the power purchase charge. The reference generated power data is created using data that shows a temporal change in the total generated power, which is the sum of the generated power of the first power generator and the generated power of the second power generator in the past,
The distributed power supply system according to claim 5 or 6, wherein the reference power consumption data is created using data that shows a temporal change in the power consumption of the power consumption device in the past.

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