JP7080165B2 - Distributed power system - Google Patents

Description

The present invention is between an AC line connected to an AC line, 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 charging / discharging unit with 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. The present invention relates to a distributed power supply system including a charge / discharge device having a charge / discharge control unit for controlling charge / discharge, and a power consumption device connected to an AC line.

Patent Document 1 describes a distributed power supply system including a photovoltaic power generation device and a charging / discharging device. In this distributed power supply system, an example in which the charging / discharging device operates in an operation mode called a green mode is described. In this green mode, when the total power consumption due to the load is larger than the generated power of the photovoltaic power generation device, that is, when a shortage power is generated, the charging / discharging device discharges the power corresponding to the shortage power. On the other hand, when surplus power that is not used by the load is generated among the power generated by the photovoltaic power generation device, the charge / discharge device charges the surplus power. However, if 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 that the buying and selling of electric power between the distributed power supply system and the electric power system is reduced.

It should be noted that Patent Document 1 does not describe a distributed power supply system in which a plurality of power generation devices are installed in addition to the charging / discharging device.

Japanese Unexamined Patent Publication No. 2015-159726

Patent Document 1 describes an example in which surplus power generated by a photovoltaic power generation device is sold, but in the case of a distributed power generation system in which a power generation device other than the photovoltaic power generation device is additionally installed, It is also assumed that the unit price of electricity sold to the power system will differ for each power generation device. In that case, the surplus power sold to the power system may be the generated power of a power generation device having a high unit selling price or the power generated by a power generation device having a low unit selling 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 be controlled so that the electric power having a low unit selling price can be charged as much as possible. That is, it is preferable that a sufficient charge margin is secured in the charge / discharge portion of the charge / discharge device before the time when the generated power of the power generation device having a low unit selling price becomes large.

The present invention has been made in view of the above problems, and an object of the present invention is an economic merit in selling electric power to an electric power system while reducing the sale and purchase of electric power to and from the electric power system. The point is to provide a distributed power supply system that increases the size of the power supply.

The characteristic configuration of the distributed power supply system according to the present invention for achieving the above object is the AC line connected to the power system, the first power generation device connected to the AC line, and the AC line. The second power generation device, a charge / discharge unit including a storage battery connected to the AC line and charging / discharging power between the AC lines, and a predetermined upper limit charge level as the upper limit of the charge level of the charge / discharge unit. A charging / discharging device having a charging / discharging control unit for controlling charging / discharging by the charging / discharging unit is provided with a predetermined lower limit charging level as the lower limit of the charging level of the charging / discharging unit, and a power consuming device is connected to the AC line. It is a distributed power supply system that has been developed.
The first power selling unit price when selling the generated power of the first power generation device to the power system is higher than the second power selling unit price when selling the generated power of the second power generation device to the power system. It is set low and
The charge / discharge control unit of the charge / discharge device is
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 greater than the power consumption of the power consuming device, the charging level of the charging / discharging unit is in the surplus power generation state. Is a surplus power coping mode in which the charging / discharging portion is charged with power corresponding to the surplus power that can be derived by subtracting the power consumption from the total power generation until the upper limit charging level is reached. Controls the operation of the charge / discharge unit with
When the total generated power is smaller than the power consumption, the total generated power can be derived by subtracting the total generated power from the power consumption until the charge level of the charge / discharge unit reaches the lower limit charge level. The operation of the charge / discharge unit is controlled in the insufficient power coping mode, which aims to discharge the corresponding power from the charge / discharge unit to the AC line.
In the case of the surplus power generation state, the unprocessed surplus power that could not be charged by the charging / discharging unit is determined to the power system based on the first power selling unit price and the second power selling unit price. Power is sold at the power selling fee,
In the case of the shortage power generation state, the unprocessed shortage power that could not be covered by the discharge of the charge / discharge unit is purchased from the power system at a predetermined power purchase fee.
When controlling the operation of the charge / discharge unit in the surplus power coping mode, the predetermined first upper limit level is set in the first time zone in which the generated power of the first power generation device becomes relatively large during the day. In the second time zone in which the power generated by the first power generation device is relatively small during the day, the charging by the charge / discharge unit is controlled by setting the upper limit charge level, and the charge is higher than the first upper limit level. A small predetermined second upper limit level is set to the upper limit charge level to control charging by the charge / discharge unit.
Here, at least one of the first power generation device and the second power generation device may be a device that uses natural energy to generate power.

According to the above-mentioned feature configuration, when the surplus power is generated, the charge / discharge device charges the surplus power as much as possible by the surplus power coping mode, and when the shortage power is generated, the shortage power is charged by the shortage power coping mode. Discharge as much as possible to cover it. By charging and discharging the charging / discharging device in this way, the amount of power exchanged with 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 generation system itself is reduced. It is effectively used in 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 coping mode, it is predetermined in the first time zone during the day when 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 charging by the charge / discharge unit, and in the second time zone in which the generated power of the first power generation device becomes relatively small during the day, the first upper limit level is set. A predetermined second upper limit level smaller than 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, there is a margin for charging a large amount of electric power in the first time zone in which the upper limit charge level is set relatively high thereafter. do. Further, in the first time zone, there is a high possibility that the surplus power, which has a low unit price for selling power to the power system, will increase. Therefore, in the first time zone in which there is a margin for charging a large amount of electric power, the generated power of the first power generation device having a low unit selling price is easily charged by the charging / discharging device. In other words, it is possible to avoid the situation where the electric power having a low unit selling price has to be sold to the electric power system as surplus electric power as much as possible.
Therefore, it is possible to provide a distributed power supply system that has a great economic merit when selling power to the power system while reducing the buying and selling of power with the power system.

Yet another characteristic configuration of the distributed power generation 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 the sunrise time and the sunset time. It is in the point of being done.

According to the above characteristic configuration, the first time zone in which the generated power of the photovoltaic power generation device is relatively large and the second time zone in which the generated power of the photovoltaic power generation device is relatively small are set as the sunrise time and the day. It can be set appropriately according to the input time of.

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

According to the above characteristic configuration, the generated power of the first power generation device is relatively relative to the time zone in which the generated power of the first power generation device actually exceeds the set generated power or is predicted to exceed the set generated power. It can be appropriately set as the first time zone when it becomes large. Further, the time zone in which the generated power of the first power generation device is actually smaller than the set generated power or predicted to be smaller than the set generated power is defined as the second time zone in which the generated power of the first power generation device is relatively small. Can be set appropriately.

Yet another characteristic configuration of the distributed power supply system according to the present invention is that the charge / discharge control unit of the charge / discharge device determines the second upper limit level to be set in the second time zone that arrives next. It is configured to perform the upper limit level determination process in advance to determine the value that minimizes the power cost in the period.
In the upper limit level determination process,
The reference power generation power data showing the temporal change of the total power generation power, which is the sum of the power generation power of the first power generation device and the power generation power of the second power generation device in the determination period, and the power consumption of the power consumption device. By referring to the reference power consumption data that shows the change over time, specify the period during which the shortage power generation state occurs and the period during which the surplus power generation state occurs.
The power purchase charge in the case of purchasing power from the power system while controlling the operation of the charge / discharge unit in the shortage power coping mode according to the power cost in the determination period in the shortage power generation state. And, in response to the surplus power generation state, the power is derived based on the power selling charge when the power is sold to the power system while controlling the operation of the charge / discharge unit in the surplus power coping mode. be.
Here, the reference power generation power data is created using data that shows the temporal change of the total power generation power, which is the sum of the power generation power of the first power generation device and the power generation power of the second power generation device in the past. , The reference power consumption data may be created by using data that shows the temporal change of the power consumption of the power consuming device in the past.

According to the above characteristic configuration, the standard power generation data of the total power generation, which is the sum of the power generated by the first power generation device and the power generated by the second power generation device in the determination period, and the standard power consumption of the power consumption device. With reference to the data, a second upper limit level can be set so that the power cost is reduced.

Yet another characteristic configuration of the distributed power supply system according to the present invention is that the charge / discharge control unit of the charge / discharge device determines the charge level of the charge / discharge unit at the end of the determination period in the upper limit level determination process. However, when the charge level of the charge / discharge unit becomes larger than the charge level of the charge / discharge unit at the start of the determination period by a predetermined increase, the charge when it is assumed that the power corresponding to the increase is sold to the power system is sold. 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, the decrease is included in the electricity charge. The point is that the charge when it is assumed that the electric power corresponding to the minute is purchased from the electric power system is included in the electric discharge charge.

According to the above feature configuration, when the power originally stored in the charge / discharge unit changes between the start time and the end time of the judgment period in the upper limit level determination process, the changed amount of power is used. Charges are included in the electricity cost calculation. As a result, the calculation of the power cost in the upper limit level determination process becomes more detailed.

It is a figure which shows the structure of the distributed power supply system. This is an example when the charging / discharging device is operating in the surplus power handling mode. This is an example when the charging / discharging device is operating in the insufficient power handling mode. It is a graph which shows the transition of electric power and charge level. It is a table explaining an example of the upper limit level determination process. It is a table explaining an example of the upper limit level determination process.

The distributed power supply system according to the 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 generation system is connected to the AC line 2 connected to the power system 1, the solar power generation device PV as the first power generation device connected to the AC line 2, and the AC line 2. A fuel cell device 10 as a second power generation device and a charging / discharging device 20 connected to an AC line 2 are provided, and a power consuming device 3 is connected to the AC line 2.

[Solar power generation device PV]
The photovoltaic power generation device PV as the first power generation device has an element (not shown) that directly converts the optical energy of the incident light (sunlight) into electrical energy, and the electric power generated by the element at a desired voltage and frequency. It is configured to have a power conversion unit (not shown) for converting to phase power and outputting to the AC line 2.

The generated power of the photovoltaic power generation device PV can be sold to the power system 1. The unit selling price (first unit selling price) when selling the generated power of the photovoltaic power generation device PV to the power system 1 is set in advance, for example, in a storage device (not shown) of the charging / discharging device 20. It is remembered. The unit price of electricity sold may be sequentially updated to a value acquired by, for example, Internet communication.

[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 has a power conversion unit 12b for converting the electric power generated by the fuel cell 12a and the fuel cell 12a 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 or the like that produces hydrogen or the like as a fuel gas 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, and the like 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 a constant power generation power such as a rated power generation power to the AC line 2.
Alternatively, the fuel cell control unit 11 of the fuel cell device 10 fuels the generated power supplied from the fuel cell unit 12 to the AC line 2 so as to follow the power consumption of the power consumption device 3 (for example, both are equal). The operation of the battery unit 12 may be controlled.

The generated power of the fuel cell device 10 can be sold to the power system 1. The unit selling price (second unit selling 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 electricity sold may be sequentially updated to a value acquired by, for example, Internet communication. In the present embodiment, the first selling unit price when selling the generated power of the photovoltaic power generation device PV to the power system 1 is the second selling price when selling the generated power of the fuel cell device 10 to the power system 1. It is set lower than the unit price of electricity. 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 generation device PV to the power system 1.

[Charging / discharging device 20]
The charging / discharging device 20 has a charging / discharging unit 22 including a storage battery 22a that charges / discharges electric power to / from the AC line 2, and a charging / discharging control unit 21 that controls the operation 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, the charging / discharging unit 22 can convert the electric power stored in the storage battery 22a into electric power having a desired voltage, frequency, and phase and output the electric power to the AC line 2. In this case, the charge / discharge control unit 21 charges / discharges the charge / discharge unit 22 with a predetermined upper limit charge level as the upper limit of the charge level of the charge / discharge unit 22 and a predetermined lower limit charge level as the lower limit of the charge level of the charge / discharge unit 22. To control. The storage battery 22a can be configured by 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. conduct.

Information about the electric power measured by the electric power measuring instrument 5 is transmitted to the charge / discharge control unit 21. In the present embodiment, the power measuring instrument 5 is provided on the upstream side (power system 1 side) of the location to which the photovoltaic power generation device PV is connected, and receives the power supplied from the power system 1 to the AC line 2. measure. If the power measured by the power measuring instrument 5 is a positive value, the distributed power supply system is buying power from the power system 1, and if the power measured by the power measuring instrument 5 is a negative value, it means that the distributed power supply system is buying power. The distributed power supply system sells power to the power system 1. The power measuring instrument 5 is configured by using, for example, a current transformer (current transformer for an instrument) used for detecting the current value of electric power in the AC line 2, and has a predetermined voltage value (for example, 100V, 200V, etc.). From the product, the power value on the AC line 2 can be derived. The power measuring instrument 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, in the charge / discharge control unit 21, the charge / discharge control unit 21 controls the charge / discharge of the charge / discharge unit 22 with reference to the measurement result of the power measuring instrument 5.

When the charging / discharging device 20 discharges power to the AC line 2, the power measured by the power measuring instrument 5 is the power consumed by the power consuming device 3 from the AC line 2, and the solar power generation device PV receives the power from the AC line 2. It is a value obtained by subtracting the sum of the generated power supplied to the AC line 2, the generated power supplied by the fuel cell device 10 to the AC line 2, and the discharge power supplied by the charging / discharging device 20 to the AC line 2. 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 measuring device 5 is the power consumed by the power consuming device 3 from the AC line 2 and the AC of the charging / discharging device 20. From the sum of the charging power charged from the line 2, the sum of the power generated by the solar power generation device PV to the AC line 2 and the power generated by the fuel cell device 10 to the AC line 2 is calculated. It becomes the subtracted value.

In the present embodiment, the charge / discharge control unit 21 of the charge / discharge device 20 controls so that the buying and selling of electric power between the distributed power supply system and the power system 1 is minimized. Specifically, the charge / discharge control unit 21 of the charge / discharge device 20 is the sum of the power generated by the solar power generation device PV (first power generation device) and the power generated by the fuel cell device 10 (second power generation device). When the total generated power is equal to or higher than the power consumed by the power consuming 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 charge / discharge unit 22 is controlled in the surplus power coping mode in which the charge / discharge unit 22 is charged with the electric power corresponding to the above. In this surplus power coping mode, the surplus power is charged to the charging / discharging unit 22 as much as possible.

On the other hand, when the total generated power is smaller than the power consumption, it corresponds to the shortage power that can be derived by subtracting the total generated power from the power consumption until the charge level of the charge / discharge unit 22 reaches the lower limit charge level. The operation of the charge / discharge unit 22 is controlled in the insufficient power coping mode, which aims to discharge the power to be generated from the charge / discharge unit 22 to the AC line 2. In this shortage power coping mode, the charging / discharging unit 22 discharges so as to cover the shortage power 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. The electric power value shown in the figure 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 the consumption of the power consumption device 3. The surplus power generation state is such that the power (0.5 kW) or more is generated. If the charging / discharging device 20 is neither charging nor discharging, 1.2 kW of electric power is sold to the power system 1, but in the example shown in FIG. 2, the charging / discharging device 20 transfers 1.1 kW of electric power. It is charging. In this way, in the charge / discharge control unit 21 of the charge / discharge device 20, the charge level of the charge / discharge unit 22 becomes the upper limit charge level so that the measured power (power selling power) of the power measuring instrument 5 becomes as small as possible. Up to, the power corresponding to the surplus power is charged from the AC line 2 to the charging / discharging unit 22. Even if the goal is to charge the charging / discharging unit 22 with the power corresponding to the surplus power, when the charging level of the charging / discharging unit 22 reaches the upper limit charging level, the charging / discharging unit 22 cannot be charged any more and is charged. When the power to be charged reaches the upper limit of the charging power of the charging / discharging unit 22 (for example, the capacity of the power conversion unit 22b), no more power can be charged. By charging the charging / discharging unit 22, 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 system 1. ..

FIG. 3 is an example of the case where the charging / discharging device 20 is operating in the insufficient power coping mode. The electric power value shown in the figure is a value described for the purpose of illustration. As shown in the figure, the total generated power (0.7 kW), which is the sum of the generated power (0 kW) of the photovoltaic power generation device PV and the generated power (0.7 kW) of the fuel cell device 10, is the consumption of the power consumption device 3. It is in a state of insufficient power generation smaller than the power consumption (2 kW). If the charging / discharging device 20 is neither charging nor discharging, 1.3 kW of electric power is purchased from the power system 1, but in the example shown in FIG. 3, the charging / discharging device 20 discharges 1.3 kW of electric power. is doing. In this way, in the charge / discharge control unit 21 of the charge / discharge device 20, the charge level of the charge / discharge unit 22 becomes the lower limit charge level so that the measured power (power purchase power) of the power measuring device 5 becomes as small as possible. Up to, the power corresponding to the insufficient power is discharged from the charge / discharge unit 22 to the AC line 2. Even when the goal is to discharge the power corresponding to the insufficient power from the charge / discharge unit 22, when the charge level of the charge / discharge unit 22 reaches the lower limit charge level, no further discharge can be performed and discharge is performed. When the power to be discharged reaches the upper limit value of the discharge power of the charge / discharge unit 22 (for example, the capacity of the power conversion unit 22b), no more power can be discharged. By discharging from the charging / discharging unit 22, the power purchased from the power system 1 is zero in the example shown in FIG. The unit price for purchasing electric power when purchasing electric power from the electric power system 1 is set in advance, and is stored in, for example, a storage device (not shown) of the charging / discharging device 20. It should be noted that this power purchase unit price may be sequentially updated to a value acquired by, for example, Internet communication or the like.

In the charge / discharge device 20 of the present embodiment, the charge / discharge control unit 21 controls charging by the charge / discharge unit 22 with a predetermined upper limit charge level as the upper limit of the charge level of the charge / discharge unit 22, but the upper limit charge level is 1. It is a variable value set for each of multiple time zones in 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 power generated by the solar power generation device PV (first power generation device) during the day is relative. In the first time zone when the target becomes 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 power generated by the solar power generation device PV during the day is relative. In the second time zone, which is smaller than the first upper limit level, 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 charging / discharging unit 22.

FIG. 4 is a graph showing changes in electric power and charge level. Specifically, FIG. 4A is a graph of the power consumption of the power consuming device 3. FIG. 4B is a graph of the power generated by the photovoltaic power generation device PV, the power generated by the fuel cell device 10, and the total power generated by them. 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 as a line graph. For example, in FIG. 4A, the average power consumption in the 7 o'clock time range is shown as the power consumption at 7 o'clock time. Further, FIG. 4 (d) is a graph of the charge level. In this graph, the transition of the charge level of the storage battery 22a at the end of one hour is shown as a line graph. For example, the charge level at the end of the time 7 o'clock is shown as the charge level at the time 7 o'clock in FIG. 4D.

As shown in FIG. 4B, the generated power of the fuel cell device 10 is constantly controlled at 0.7 kW. The generated power of the photovoltaic power generation device PV is generated between 6 o'clock and 17 o'clock. In this way, since the photovoltaic power generation device PV is a device that generates power by using natural energy, the magnitude of the generated power changes according to the natural energy (irradiation light intensity of sunlight), that is, the generated power. The size cannot be freely controlled, and there are times when the generated power is relatively large and times when the generated power is relatively small. In the present embodiment, the time zone in which the generated power of the photovoltaic power generation device PV is relatively large is set as the first time zone, and the time zone in which the generated power is relatively small is set as the second time zone. In the example shown in FIG. 4, the period from time 6:00 to time 18:00 is the first time zone, and the period from time 18:00 to time 6:00 on the next day is the second time zone.

In the case of the photovoltaic power generation device PV, since the generated power changes according to the received solar 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 charge / discharge control unit 21 of the charge / discharge device 20 sets the period from the sunrise time to the sunset time as the first time zone with reference to the calendar information, and sets the period from the sunset time to the sunrise time as the second time. Can be set as a band. In other words, since the sunset time and the sunrise time change throughout the year, the time zone in which the generated power of the solar power generation device PV is relatively large and the time zone in which the power generated by the solar power generation device PV is relatively small is one year. Although it changes within, the first time zone and the second time zone can be appropriately set by referring to the calendar information.

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

For example, when the charge / discharge control unit 21 of the charge / discharge device 20 can obtain information on the generated power of the photovoltaic power generation device PV, data or the like that shows past changes in the generated power of the photovoltaic power generation device PV, etc. (For example, the power generation data of the PV of the photovoltaic power generation device for the last few days, etc.), the time zone (first time zone) in which the power generation power of the PV of the photovoltaic power generation device is predicted to be equal to or higher than the set power generation power, and A time zone (second time zone) that is predicted to be smaller than the set power generation can be specified in advance.

In addition, if the charge / discharge control unit 21 of the charge / discharge device 20 can obtain information about the generated power of the photovoltaic power generation device PV, the photovoltaic power generation can be performed by referring to the generated power of the current photovoltaic power generation device PV. It is possible to determine whether or not the generated power of the device PV is equal to or higher than the set generated power. Therefore, the charge / discharge control unit 21 of the charge / discharge device 20 refers to the generated power of the current photovoltaic power generation device PV, and if the generated power is equal to or higher than the set generated power, it is currently in the first time zone. If the generated power is smaller than the set generated power, it can be determined that it is currently in the second time zone.

As shown in FIG. 4C, insufficient power is generated in 6 hours from 18:00 to 0:00. That is, during those 6 hours, 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 in a state of insufficient power generation smaller than the power consumption of the power consumption device 3. On the other hand, surplus power is generated in 18 hours from 0:00 to 18:00. That is, the 18 hours are 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 higher 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, no further charging is possible. Alternatively, if the power to be charged reaches the upper limit of the charging power of the charging / discharging unit 22 (for example, the capacity of the power conversion unit 22b), no more power can be charged. In that case, the unprocessed surplus power that could not be charged by the charging / discharging unit 22 in the surplus power generation state is determined to the power system 1 based on the first power selling unit price and the second power selling unit price. Electricity is sold at the electricity selling fee (unit price x electric energy).

Similarly, even if the shortage power as shown in FIG. 4C occurs, it is not always possible to cover all of the shortage power with the discharge power of the charging / discharging device 20. For example, if the charge level of the charge / discharge unit 22 of the charge / discharge device 20 reaches the lower limit charge level, further discharge cannot be performed. Alternatively, if the power to be discharged reaches the upper limit of the discharge power of the charge / discharge unit 22 (for example, the capacity of the power conversion unit 22b), no more power can be discharged. In that case, the unprocessed insufficient power that could not 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 x electric energy). ..

As described above, when the charge level of the charge / discharge unit 22 of the charge / discharge device 20 reaches the upper limit charge level, the unprocessed surplus power generated thereafter must be sold to the power system 1, and the charge / discharge device must be sold. Considering that if the charge level of the charge / discharge unit 22 of 20 reaches the lower limit charge level, the unprocessed insufficient power generated after that must be purchased from the power system 1, when selling the power to the power system 1. 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 charged before the time when the generated power of the power generation device having a low selling price becomes large so that the power having a low unit selling price is charged by the charging / discharging device 20 as much as possible. It is preferable that a sufficient charge margin is secured.

In the present embodiment, since the unit price of the photovoltaic power generation device PV is set to be lower than the unit price of the photovoltaic power generation device 10, the second time zone in which the generated power of the photovoltaic power generation device PV becomes relatively small. Then, the charging to the charging / discharging unit 22 is suppressed so that the charging / discharging unit 22 can be charged as much as possible with the power having a low unit selling price in the first time zone when the generated power of the photovoltaic power generation device PV becomes relatively large. Is preferable. 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 power generated by the solar power generation device PV (first power generation device) during the day. In the first time zone when In the second time zone, which is relatively small, 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 charging / discharging unit 22. Therefore, the charge / discharge control unit 21 of the charge / discharge device 20 determines the upper limit level for determining the second upper limit level to be set in the next second time zone to be the value at which the power cost in the predetermined determination period is the smallest. 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, there is a margin for charging a large amount of electric power in the first time zone in which the upper limit charge level is set relatively high thereafter. do. Further, in the first time zone, there is a high possibility that the surplus power having a low unit price for selling power to the power system 1 will increase. Therefore, in the first time zone in which there is a margin for charging a large amount of electric power, the generated power of the photovoltaic power generation device PV having a low unit selling price is easily charged by the charging / discharging device 20. In other words, it is possible to avoid a situation in which the electric power having a low unit selling price has to be sold to the electric power system 1 as surplus electric power as much as possible.

To give a specific example, in the charge / discharge control unit 21 of the charge / discharge device 20, in the upper limit level determination process, the power generated by the solar power generation device PV (first power generation device) and the fuel cell device 10 ( Insufficient power by referring to the standard power generation data that shows the temporal change of the total generated power, which is the sum of the generated power of the second power generation device), and the standard power consumption data that shows the time change of the power consumption of the power consumption device 3. Specify the period during which the power is generated and the period during which the surplus power is generated. For example, the standard power generation data is created using data that shows the temporal change of the total power generation, which is the sum of the power generated by the PV of the photovoltaic power generation device in the past and the power generated by the fuel cell device 10, and the standard power consumption. The data is created using data that shows the temporal changes in the power consumption of the power consumption device 3 in the past. Then, the charge / discharge control unit 21 purchases power from the power system 1 while controlling the operation of the charge / discharge unit 22 in the shortage power coping mode according to the power cost in the determination period. It is derived based on the power purchase charge of the above and the power sale charge when the power is sold to the power system 1 while controlling the operation of the charge / discharge unit 22 in the surplus power coping mode according to the surplus power generation state.

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

Reference power generation data that shows the temporal change of the total power generation power, which is the sum of the power generation power of the solar power generation device PV and the power generation power of the fuel cell device 10 as shown in FIGS. 5 and 6, and the consumption of the power consumption device 3. By referring to the standard power consumption data that shows the change over time of power, it is possible to specify the period during which the shortage power generation occurs and the period during which the surplus power generation occurs. Then, the power cost in the determination period of these two days is the power purchase when the power is purchased from the power system 1 while controlling the operation of the charge / discharge unit 22 in the shortage power coping mode according to the shortage power generation state. It can be derived based on the charge and the power selling charge when the power is sold to the power system 1 while controlling the operation of the charge / discharge unit 22 in the surplus power coping mode according to the surplus power generation state.

In the examples shown in FIGS. 5 and 6, of the surplus power generated between the time 11:00 and the time 17:00 one 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 power generated by the photovoltaic power generation device PV having a low unit selling price is sold to the power system 1 at 3 yen / kWh. Further, 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 power cost in the judgment period for a total of 2 days (48 hours in total) from 18:00 two days ago to 18:00 on the current day is "-14.1 yen". By performing such calculation of the power cost 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 is performed. You can specify the value of the level.

In Table 1 below, the second upper limit level set in the second time zone between 18:00 and 6:00 is set to 0 (kWh), 1 (kWh), 2 (kWh), 3 (kWh), 4 ( It is the result of the calculated value of the 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, the charge / discharge control unit 21 of the charge / discharge device 20 sets the second upper limit level to be set in the next coming second time zone to 0 (kWh) in the upper limit level setting process.

<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, the fuel cell device 10 has been mentioned as an example of the second power generation device of the present invention, but there are various types of power generation devices such as a type of power generation device including an engine and a generator driven by the engine. 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 appropriately changed.
Further, in the above embodiment, the case where the first power generation device is the photovoltaic 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 as appropriate. Although a photovoltaic power generation device is exemplified as a device that generates power using natural energy, a device that generates power using other natural energy such as tidal force and wind power can also be adopted.

<2>
In the above embodiment, the charging level (5kWh) of the charging / discharging unit 22 at the start of the determination period shown in FIGS. 5 and 6 is different from the charging level (3.6kWh) at the end of the charging / discharging unit 22. In this example, by using 1.4kWh of the electric power originally stored in the charge / discharge unit 22, the charge level of the charge / discharge unit 22 at the end of the determination period is higher than the charge level at the start. Is also reduced by 1.4kWh. That is, the power of 1.4kWh was procured from the power system 1 and should be included in the calculation of the power cost, but it was covered by the discharge from the charging / discharging unit 22 (that is, included in the calculation of the power cost). It can be said that there was no such thing. Therefore, when the charge level of the charge / discharge 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 power cost calculation. Is preferable.

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

<3>
In the above embodiment, the case where the determination period is 2 days is illustrated, but the length of the determination period can be appropriately set.

<4>
In the above embodiment, the unit price of selling power to the power system 1, the unit price of buying power 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 embodiment, the reference power generation data is created using the data showing the time change of the past total power generation power, and the reference power consumption data is created using the data showing the time change of the past power consumption. Although an example has been described, the reference power generation data and the reference power consumption data may be other data. For example, the reference power generation data is the total power generation power which is the sum of the power generation power of the solar power generation device PV (first power generation device) and the power generation power of the fuel cell device 10 (second power generation device) in the above determination period. The predicted value data may be the predicted value data showing the change over time, and the reference power consumption data may be the predicted value data showing the time change of the power consumption of the power consuming device 3 in the determination period.

<6>
The configurations disclosed in the above embodiment (including other embodiments, the same shall apply hereinafter) can be applied in combination with the configurations disclosed in other embodiments as long as there is no contradiction, and are also disclosed herein. The embodiment is an example, and the embodiment of the present invention is not limited to this, and can be appropriately modified 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 the economic merit is increased when selling power to the power system while reducing the buying and selling of power with the power system.

1 Power system 2 AC line 3 Power consumption device 10 Fuel cell device (second power generation device)
11 Fuel cell control unit 12 Fuel cell unit 12a Fuel cell 12b Power conversion unit 20 Charging / discharging device 21 Charging / discharging control unit 22 Charging / discharging unit 22a Storage battery 22b Power conversion unit 5 Power measuring instrument PV photovoltaic power generation device (first power generation device)

Claims (7)

Between the AC line connected to the power system, the first power generation device connected to the AC line, the second power generation device connected to the AC line, and the AC line connected to the AC line. The charge / discharge unit including a storage battery for charging / discharging electric power, and the predetermined upper limit charge level is set as the upper limit of the charge level of the charge / discharge unit, and the predetermined lower limit charge level is set as the lower limit of the charge level of the charge / discharge unit. A distributed power supply system including a charge / discharge device having a charge / discharge control unit for controlling charge / discharge by the discharge unit, and a power consuming device connected to the AC line.
The first power selling unit price when selling the generated power of the first power generation device to the power system is higher than the second power selling unit price when selling the generated power of the second power generation device to the power system. It is set low and
The charge / discharge control unit of the charge / discharge device is
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 greater than the power consumption of the power consuming device, the charging level of the charging / discharging unit is in the surplus power generation state. Is a surplus power coping mode in which the charging / discharging portion is charged with power corresponding to the surplus power that can be derived by subtracting the power consumption from the total power generation until the upper limit charging level is reached. Controls the operation of the charge / discharge unit with
When the total generated power is smaller than the power consumption, the total generated power can be derived by subtracting the total generated power from the power consumption until the charge level of the charge / discharge unit reaches the lower limit charge level. The operation of the charge / discharge unit is controlled in the insufficient power coping mode, which aims to discharge the corresponding power from the charge / discharge unit to the AC line.
In the case of the surplus power generation state, the unprocessed surplus power that could not be charged by the charging / discharging unit is determined to the power system based on the first power selling unit price and the second power selling unit price. Power is sold at the power selling fee,
In the case of the shortage power generation state, the unprocessed shortage power that could not be covered by the discharge of the charge / discharge unit is purchased from the power system at a predetermined power purchase fee.
When the operation of the charge / discharge unit is controlled in the surplus power coping mode, the predetermined first upper limit level is set in the first time zone in which the generated power of the first power generation device becomes relatively large during the day. In the second time zone in which the power generated by the first power generation device is relatively small during the day, the charging by the charge / discharge unit is controlled by setting the upper limit charge level, and the charge is higher than the first upper limit level. A distributed power supply system that controls charging by the charging / discharging unit by setting a small predetermined second upper limit level to the upper limit charging 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 generates power by utilizing natural energy. The first power generation device is a solar power generation device.
The distributed power supply system according to claim 2, wherein the first time zone and the second time zone are set according to the sunrise time and the sunset time. The first time zone includes a time zone in which the generated power of the first power generation device is expected to be equal to or higher than the set generated power or equal to or higher than the set generated power.
The distributed power source 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 generation device is smaller than the set power generation power or is predicted to be smaller than the set power generation power. .. The charge / discharge control unit of the charge / discharge device determines the upper limit level for determining 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,
The reference power generation power data showing the temporal change of the total power generation power, which is the sum of the power generation power of the first power generation device and the power generation power of the second power generation device in the determination period, and the power consumption of the power consumption device. By referring to the reference power consumption data that shows the change over time, specify the period during which the shortage power generation state occurs and the period during which the surplus power generation state occurs.
The power purchase charge in the case of purchasing power from the power system while controlling the operation of the charge / discharge unit in the shortage power coping mode according to the power cost in the determination period in the shortage power generation state. The claim is derived based on the power selling charge when selling power to the power system while controlling the operation of the charging / discharging unit in the surplus power coping mode according to the surplus power generation state. The distributed power supply system according to any one of 1 to 4. The charge / discharge control unit of the charge / discharge device is used in the upper limit level determination process.
When the charge level of the charge / discharge unit at the end of the determination period is larger than the charge level of the charge / discharge unit at the start of the determination period by a predetermined increase, the power corresponding to the increase is achieved. Is included in the power sale charge when it is assumed that the power system is sold 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, the power corresponding to the decrease. The distributed power supply system according to claim 5, wherein the charge when it is assumed that the power system is purchased from the power system is included in the power purchase charge. The reference power generation power data is created by using data that shows the temporal change of the total power generation power, which is the sum of the power generation power of the first power generation device and the power generation power of the second power generation device in the past.
The distributed power supply system according to claim 5 or 6, wherein the reference power consumption data is created by using data showing a time change of the power consumption of the power consuming device in the past.

Images