Control System and Management System

Abstract

Reduce the possibility that the command value distributed to each power storage unit becomes a minute value. 【Solution means】 The control system 40 is a control system that controls a power storage system that adjusts the active power at the synthesis point with the power grid by a plurality of power storage units including power storage devices that discharge and charge DC power. The control system includes a command calculation unit 51 that calculates a total DC power command value Cp, which is the total value of the power that the power storage devices in the plurality of power storage units should discharge or charge; a command distribution unit 52 that calculates an active power distribution value P[m] to be distributed to each of the plurality of power storage units from among the total DC power command value Cp; and an operation instruction unit 53 that instructs each of the plurality of power storage units of the active power distribution value P[m] of the power storage unit. When the power distribution value calculated for the first power storage unit among the plurality of power storage units is a numerical value within the first range, the command distribution unit 52 distributes the power distribution value to one or more power storage units other than the first power storage unit among the plurality of power storage units.

Description

Technical Field

[0001] The present disclosure relates to a technique for controlling a plurality of power storage devices.

Background Art

[0002] For example, a technique for controlling a plurality of power storage devices according to a command value of power to be exchanged with a power grid has been conventionally proposed. For example, Patent Document 1 discloses a configuration for controlling the charge and discharge of each storage battery according to a command value based on a charge request or a discharge request in a storage battery system including a plurality of banks each composed of an AC-DC converter and a storage battery.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the command value for instructing charging or discharging of each power storage device is a non-zero numerical value that is sufficiently small (hereinafter referred to as "minute value"), problems such as inability to accurately measure the charge amount or discharge amount of each power storage device are assumed. In view of the above circumstances, one aspect of the present disclosure aims to reduce the possibility that the command value allocated to each power storage unit becomes a minute value.

Means for Solving the Problems

[0005] To solve the above problems, a control system according to one aspect of the present disclosure controls a power storage system that adjusts power at a connection point with a power grid by a plurality of power storage units each including a power storage device that discharges and charges DC power. The control system includes a command calculation unit that calculates a total DC power command value, which is the total value of the power that the power storage devices in the plurality of power storage units should discharge or charge; a command distribution unit that calculates a power distribution value to be distributed to each of the plurality of power storage units from the total DC power command value; and an operation instruction unit that instructs each of the plurality of power storage units of the power distribution value of the power storage unit. When the power distribution value calculated for the first power storage unit among the plurality of power storage units is a value within a first range, the command distribution unit distributes the power distribution value to one or more power storage units other than the first power storage unit among the plurality of power storage units.

[0006] A management system according to one aspect of the present disclosure includes a power storage system that adjusts active power at a connection point with a power grid by a plurality of power storage units each including a power storage device that discharges and charges DC power, and a control system that controls the power storage system. The control system includes a command calculation unit that calculates a total DC power command value, which is the total value of the power that the power storage devices in the plurality of power storage units should discharge or charge; a command distribution unit that calculates a power distribution value to be distributed to each of the plurality of power storage units from the total DC power command value; and an operation instruction unit that instructs each of the plurality of power storage units of the power distribution value of the power storage unit. When the power distribution value calculated for the first power storage unit among the plurality of power storage units is a value within a first range, the command distribution unit distributes the power distribution value to one or more power storage units other than the first power storage unit among the plurality of power storage units.

Brief Description of Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

Figure 22

Embodiments for Carrying Out the Invention

[0008] Embodiments for carrying out the present disclosure will be described with reference to the drawings. Note that the embodiments described below are exemplary embodiments assumed when implementing the present disclosure. Therefore, the scope of the present disclosure is not limited to the embodiments illustrated below.

[0009] 1. First Embodiment FIG. 1 is a block diagram illustrating the configuration of a management system 100 according to the first embodiment. The management system 100 is a system that exchanges AC power with the power grid 10. The power grid 10 is, for example, a power distribution system or a power transmission system for supplying AC power generated by a power generation facility 23 (not shown), such as a thermal power plant or a nuclear power plant, to consumers such as business facilities or ordinary households. The management system 100 is connected to the power grid 10 at the connection point 11. The connection point 11 is a connection point corresponding to the boundary between the power grid 10 and the management system 100.

[0010] As illustrated in FIG. 1, the management system 100 includes a substation facility 21, a load facility 22, a power storage system 30, and a control system 40. The power storage system 30 is a power facility that exchanges AC power with the power grid 10.

[0011] The substation equipment 21 is power equipment that aggregates the outputs of a plurality of power storage units U[m] constituting the power storage system 30 and the inputs of the load equipment 22, and transforms the voltage of the AC power transmitted and received between these and the synthesis point 11 using a transformer. Note that the transformer of the substation equipment 21 may be omitted. The load equipment 22 is various loads (in-station loads) that operate by consuming power supplied from the power storage system 30 or the power grid 10. For example, the load equipment 22 includes various equipment that supplies control power, operating power, or auxiliary power to each element of the management system 100 (substation equipment 21, power storage system 30, or control system 40). Specifically, an in-station transformer that transforms the supply voltage from the substation equipment 21, a DC power supply device that supplies control power or operating power to the substation equipment 21 or the AC-DC converter 322, an uninterruptible power supply (UPS) that supplies power in the event of an abnormality, a power supply device that supplies auxiliary power (for example, the drive power required for auxiliary equipment such as air conditioning equipment) or control power to the power storage device 31, a fuel transfer pump or cooling fan used in the substation equipment 21 and the AC-DC converter 322, a communication device used for security telephones with power companies, lighting equipment or air conditioning equipment installed in the site or building, a measurement system that measures environmental information such as temperature or humidity, or various fire protection equipment (smoke detectors, heat detectors, fire alarms, etc.) are exemplified as the load equipment 22. Note that the load equipment 22 may be omitted.

[0012] The power storage system 30 of the first embodiment is composed of a plurality of power storage units U[m] (m = 1 to 5). In the following description, for convenience, a form in which the power storage system 30 includes five power storage units U[1] to U[5] is exemplified. However, the number of power storage units U[m] constituting the power storage system 30 can be arbitrarily changed.

[0013] Each of the plurality of power storage units U[m] is power equipment capable of charging and discharging power. As illustrated in FIG. 1, each power storage unit U[m] includes a power storage device 31 and a power conditioner 32. The power storage device 31 is a secondary battery that discharges and charges DC power. The type of the power storage device 31 is arbitrary, and for example, a lithium-ion battery or a sodium-sulfur battery is exemplified as the power storage device 31.

[0014] The power conditioner 32 is a PCS (Power Conditioning System) that controls the discharge and charge of the energy storage device 31. Specifically, the power conditioner 32 includes a transformer 321 and an AC / DC converter 322. The transformer 321 converts the voltage of the AC power. The AC / DC converter 322 mutually converts DC power and AC power. Specifically, the AC / DC converter 322 converts the DC power supplied by the discharge of the energy storage device 31 into AC power, and the transformer 321 converts the voltage of the AC power after conversion by the AC / DC converter 322 and supplies it to the synthesis point 11. Also, the transformer 321 converts the voltage of the AC power supplied from the power grid 10, converts the AC power after transformation by the transformer 321 into DC power, and supplies it to the energy storage device 31. As described above, the energy storage system 30 adjusts the active power at the synthesis point 11 with the power grid 10 by a plurality of energy storage units U[m] including the energy storage device 31. Note that the transformer 321 may be omitted. Also, a plurality of energy storage units U[m] may share one transformer 321.

[0015] The control system 40 is a computer system (PMS: Power Management System) that controls the energy storage system 30. Specifically, the control system 40 instructs an active power distribution value P[m] for each energy storage unit U[m] of the energy storage system 30. Each energy storage unit U[m] causes the energy storage device 31 to execute discharge or charge of DC power corresponding to the active power distribution value P[m]. The active power distribution value P[m] is the power value of the AC power that the energy storage unit U[m] should discharge or charge. Specifically, a positive number of the active power distribution value P[m] corresponds to a discharge command (i.e., power supply from the energy storage unit U[m] to the synthesis point 11), and a negative number of the active power distribution value P[m] corresponds to a charge command (i.e., power reception by the energy storage unit U[m] from the synthesis point 11). Note that a negative number of the active power distribution value P[m] may correspond to a discharge command, and a positive number of the active power distribution value P[m] may correspond to a charge command.

[0016] FIG. 2 is a block diagram illustrating the configuration of the control system 40. As illustrated in FIG. 2, the control system 40 includes a control device 41, a storage device 42, and a transmission / reception device 43. Note that the control system 40 can be realized by a single device or by a plurality of devices configured separately from each other.

[0017] The control device 41 is composed of one or more processors that control each element of the control system 40. Specifically, for example, the control device 41 is composed of one or more types of processors such as a PLD (Programmable Logic Device), a CPU (Central Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), or an ASIC (Application Specific Integrated Circuit).

[0018] The storage device 42 is one or more memories that store the programs executed by the control device 41 and the data used by the control device 41. The storage device 42 is composed of a known recording medium such as a magnetic recording medium or a semiconductor recording medium, for example. The storage device 42 may be composed of a combination of multiple types of recording media. A portable recording medium detachable from the control system 40 may be used as the storage device 42.

[0019] The transmission / reception device 43 transmits and receives signals to and from an external device by wire or wirelessly. Specifically, the transmission / reception device 43 communicates with each power storage unit U[m] (specifically, the power conditioner 32) via a communication network (not shown) such as a dedicated line, for example. For example, the active power distribution value P[m] is transmitted from the transmission / reception device 43 to each power storage unit U[m]. Note that the signals exchanged between the transmission / reception device 43 and each power storage unit U[m] (specifically, the power conditioner 32) may be either digital signals or analog signals.

[0020] FIG. 3 is a block diagram illustrating the functional configuration of the control system 40. The control device 41 realizes a plurality of functions (command calculation unit 51, command distribution unit 52, operation instruction unit 53) for controlling a plurality of power storage units U[m] by executing a program stored in the storage device 42.

[0021] As illustrated in FIG. 3, a basic command value C0 is input to the control system 40. The basic command value C0 is a command value for the active power (hereinafter referred to as "synthesis point power") at the synthesis point 11 with the power grid 10. That is, the basic command value C0 is the total value of the power to be discharged or charged by the entire management system 100. In addition to indicating the numerical value of the synthesis point power, the basic command value C0 indicates the direction of the power with respect to the synthesis point 11 (discharge / charge) by a sign. Specifically, power supply from the power storage system 30 to the synthesis point 11 (that is, discharge by the power storage unit U[m]) is indicated by a positive number, and power reception from the synthesis point 11 by the power storage system 30 (that is, charge by the power storage unit U[m]) is indicated by a negative number.

[0022] The basic command value C0 is transmitted from an external system that manages a power market, such as a wholesale power market or a supply-demand adjustment market, to the control system 40. That is, the basic command value C0 is the total value of the power that the management system 100 should trade in various power markets.

[0023] The command calculation unit 51 in FIG. 3 calculates the total DC power command value Cp from the basic command value C0. The total DC power command value Cp is a command value obtained by adding the power loss from the power storage device 31 of each power storage unit U[m] to the synthesis point 11 to the basic command value C0. Specifically, the total DC power command value Cp designates the total value of the DC power that each power storage device 31 should generate so that the synthesis point power is maintained at the basic command value C0 even when power loss is associated from each power storage device 31 to the synthesis point 11. That is, the total DC power command value Cp is the total value of the DC power that the power storage devices 31 in the plurality of power storage units U[m] should discharge or charge in order to realize the basic command value C0.

[0024] FIG. 4 is an equivalent circuit diagram obtained by virtually integrating a plurality of power storage units U[m]. As illustrated in FIG. 4, the power storage devices 31 in the plurality of power storage units U[m] are equivalently replaced by one power storage device 31eq, and the power conditioning devices 32 in the plurality of power storage units U[m] are equivalently replaced by one power conditioning device 32eq.

[0025] As illustrated in FIG. 4, the total DC power command value Cp calculated by the command calculation unit 51 is the total value of the DC power that the power storage device 31eq should discharge or receive. As understood from the above description, the total DC power command value Cp can also be expressed as a value obtained by equivalently converting the AC power to be set at the synthesis point 11 (i.e., the synthesis point power specified by the basic command value C0) into the DC power generated by the power storage device 31.

[0026] As illustrated in FIG. 4, in the path from the power storage device 31 of each power storage unit U[m] to the synthesis point 11, a transformation loss X1, a load loss X2, and a conversion loss X3 occur.

[0027] The transformation loss X1 is a power loss caused by voltage transformation by the transformation facility 21. That is, the transformation loss X1 is a loss (e.g., load loss and no-load loss) generated by voltage transformation between the AC voltage between the power storage system 30 and the transformation facility 21 and the voltage at the synthesis point 11.

[0028] The transformation loss X1 is calculated by adding the calculated value of the copper loss generated in the transformer of the transformation facility 21 when the power corresponding to the basic command value C0 passes through the synthesis point 11 to each other, and the iron loss generated in the transformer of the transformation facility 21 when a voltage is applied to the transformation facility 21. The stray load loss or dielectric loss of the transformer in the transformation facility 21 may be added to the transformation loss X1. Note that the transformation loss X1 may be calculated by the absolute value of the difference between the power at the synthesis point 11 corresponding to the basic command value C0 (or the measured value by the power meter installed at the synthesis point 11) and the measured value by the meter installed at the input of the transformation facility 21. Also, the line loss between the power storage system 30 and the transformation facility 21 may be added to the transformation loss X1.

[0029] The load loss X2 is a power loss resulting from the power consumption by the load equipment 22. That is, the load loss X2 corresponds to the active power consumed by the load equipment 22. The load loss X2 is calculated, for example, according to the measured value measured by a measuring instrument. Note that the load loss X2 may be calculated according to a planned value preset for the load equipment 22. Also, the line loss between the power storage system 30 and the load equipment 22 may be added to the load loss X2.

[0030] The conversion loss X3 is a power loss obtained by summing up the conversion losses x[m] caused by the power conversion by the power conditioning device 32 of each power storage unit U[m] over a plurality of power storage units U[m]. The conversion loss x[m] of each power storage unit U[m] is a loss generated by the conversion between the DC power between the power storage device 31 and the power conditioning device 32 and the AC power between the control system 40 and the substation equipment 21.

[0031] The conversion loss x[m] is the sum of the loss of the transformer 321 (such as load loss and no-load loss) in the power storage unit U[m] and the loss of the AC-DC converter 322. The line loss between the transformer 321 and the AC-DC converter 322 may be added to the conversion loss x[m].

[0032] The loss of the transformer 321 is calculated by adding the calculated value of the copper loss of the transformer 321 that occurs when the power corresponding to the active power distribution value P[m] passes through the transformer 321 mutually and the iron loss of the transformer 321 that occurs when a voltage is applied to the transformer 321. The stray load loss or dielectric loss of the transformer 321 may be added to the conversion loss x[m]. Note that the loss of the transformer 321 may be calculated by the absolute value of the difference between the power corresponding to the active power distribution value P[m] input to the transformer 321 (or the measured value by the power measuring instrument provided for the input of the transformer 321) and the measured value by the power measuring instrument provided for the output of the transformer 321.

[0033] The loss of the AC-DC converter 322 is calculated, for example, by the absolute value of the difference between the active power distribution value P[m] (or the measured value by the power measuring instrument installed on the AC side of the AC-DC converter 322) and the measured value of the DC power.

[0034] Figures 5 and 6 are explanatory diagrams of the operation of the command calculation unit 51. Figure 5 shows the operation of the command calculation unit 51 when the discharge by the power storage system 30 is instructed by the basic command value C0 (C0 > 0). As illustrated in Figure 5, the command calculation unit 51 calculates the total DC power command value Cp by adding the power loss (X1 + X2 + X3) including the substation loss X1, the load loss X2, and the conversion loss X3 to the basic command value C0. In Figure 5, since the conversion loss x[m] of each power storage unit U[m] is "1", a state where the conversion loss X3 is "5" is illustrated.

[0035] Figure 6 shows the operation of the command calculation unit 51 when the charging by the power storage system 30 is instructed by the basic command value C0 (C0 < 0). While the basic command value C0 is negative, the substation loss X1, the load loss X2, and the conversion loss X3 are positive. Even when the charging by the power storage system 30 is instructed by the basic command value C0, similar to the case of Figure 5, the command calculation unit 51 calculates the total DC power command value Cp by adding the power loss (X1 + X2 + X3) including the substation loss X1, the load loss X2, and the conversion loss X3 to the basic command value C0.

[0036] That is, as expressed by the following mathematical formula (1), the command calculation unit 51 calculates the total DC power command value Cp by adding the substation loss X1, the load loss X2, and the conversion loss X3 to the basic command value C0.

Number

[0037] The command distribution unit 52 in Figure 3 calculates the command value of the active power (hereinafter referred to as "active power distribution value P[m]") to be distributed to each of the plurality of power storage units U[m] among the total DC power command value Cp. The active power distribution value P[m] is the command value of the AC power for which each power storage unit U[m] should discharge (P[m] > 0) or charge (P[m] < 0).

[0038] The operation instruction unit 53 instructs each of the plurality of power storage units U[m] of the effective power distribution value P[m] of the power storage unit U[m]. Specifically, the operation instruction unit 53 transmits the effective power distribution value P[m] calculated by the command distribution unit 52 to the power storage unit U[m] by the transmission and reception device 43.

[0039] FIG. 7 is a block diagram illustrating a specific configuration of the command distribution unit 52. As illustrated in FIG. 7, the command distribution unit 52 includes a coefficient setting unit 521, a limit value setting unit 522, and a distribution processing unit 523.

[0040] The coefficient setting unit 521 sets distribution coefficients K[m] (K[1] to K[5]) for each of the plurality of power storage units U[m]. Each distribution coefficient K[m] is a positive number representing the ratio of the power that the power storage unit U[m] should share in the total DC power command value Cp. The coefficient setting unit 521 of the first embodiment sets the distribution coefficient K[m] according to, for example, the specifications or states of the respective power storage devices 31.

[0041] The limit value setting unit 522 sets limit values L[m] (L[1] to L[5]) for each of the plurality of power storage units U[m]. Each limit value L[m] is a numerical value for restricting the effective power distribution value P[m] within a predetermined range. The limit value L[m] includes a limit value L[m]_d (d: discharge) regarding the discharge of the power storage device 31 and a limit value L[m]_c (c: charge) regarding the charge of the power storage device 31. The limit value setting unit 522 of the first embodiment sets the limit value L[m] according to, for example, the specifications or states of the respective power storage devices 31.

[0042] The distribution processing unit 523 calculates the effective power distribution value P[m] to be distributed to each power storage unit U[m] from the total DC power command value Cp. The distribution processing unit 523 of the first embodiment distributes the total DC power command value Cp to a plurality of effective power distribution values P[m] according to the distribution coefficient K[m] set by the coefficient setting unit 521 for each power storage unit U[m] and the limit value L[m] (L[m]_d, L[m]_c) set by the limit value setting unit 522 for each power storage unit U[m].

[0043] Figs. 8 to 11 are explanatory diagrams of the operation by the distribution processing unit 523. First, Fig. 8 is a specific example of the operation of the distribution processing unit 523 when the total DC power command value Cp indicates discharge (Cp > 0).

[0044] In step Sa1, the distribution processing unit 523 calculates the power distribution value Pa[m] to be distributed to each power storage unit U[m] among the total DC power command value Cp according to the distribution coefficient K[m] of each power storage unit U[m]. Specifically, the distribution processing unit 523 calculates each power distribution value Pa[m] such that each power distribution value Pa[m] is in the ratio corresponding to the distribution coefficient K[m].

[0045] For example, the distribution processing unit 523 calculates each power distribution value Pa[m] by the operation of the following formula (2). That is, the distribution processing unit 523 multiplies the ratio of each distribution coefficient K[m] to the total value ΣK[m] of the plurality of distribution coefficients K[m] (K[1] to K[5]) by the total DC power command value Cp of the discharge illustrated in Fig. 5 to calculate each power distribution value Pa[m]. As understood from the above description, according to the first embodiment, the total DC power command value Cp can be distributed to each of the plurality of power storage units U[m] according to the distribution coefficient K[m] of each power storage unit U[m].

Equation

[0046] The power distribution value Pa[m] calculated in step Sa1 may exceed the discharge limit value L[m]_d. When the total DC power command value Cp indicates discharge, the case where the power distribution value Pa[m] exceeds the limit value L[m]_d means the case where the power distribution value Pa[m] is greater than the limit value L[m]_d (Pa[m] > L[m]_d). For example, in Fig. 8, the case where the power distribution value Pa[1] (= 50) of the power storage unit U[1] exceeds the limit value L[1]_d (= 40) and the power distribution value Pa[2] (= 40) of the power storage unit U[2] exceeds the limit value L[2]_d (= 30) is illustrated.

[0047] The distribution processing unit 523 distributes the total excess value E1, which is the sum of the excess values (Pa[m] - L[m]_d) for one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pa[m] exceeds the limit value L[m]_d, to each of one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pa[m] does not exceed the limit value L[m]_d (Sa2 to Sa5).

[0048] Specifically, in step Sa2 of FIG. 8, the distribution processing unit 523 calculates the total excess value E1 by summing the differences (i.e., excess values) between the power distribution value Pa[m] and the limit value L[m]_d for one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pa[m] exceeds the limit value L[m]_d. In the situation of FIG. 8, "20", which is the sum of "10", the excess value (Pa[1] - L[1]_d) of the power storage unit U[1], and "10", the excess value (Pa[2] - L[2]_d) of the power storage unit U[2], is calculated as the total excess value E1.

[0049] In step Sa3, the distribution processing unit 523 calculates the total available power E2 by summing the differences (i.e., available margins) between the limit value L[m]_d and the power distribution value Pa[m] for one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pa[m] does not exceed the limit value L[m]_d. In the situation of FIG. 8, "30", which is the sum of "10", the available margin (L[4]_d - Pa[4]) of the power storage unit U[4], and "20", the available margin (L[5]_d - Pa[5]) of the power storage unit U[5], is calculated as the total available power E2.

[0050] In step Sa4, the distribution processing unit 523 calculates an additional distribution value ΔP[m] for one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pa[m] does not exceed the limit value L[m]_d. Specifically, the distribution processing unit 523 calculates each additional distribution value ΔP[m] by the operation of the following mathematical formula (3a). That is, the distribution processing unit 523 calculates the additional distribution value ΔP[m] by multiplying the ratio of each margin value (L[m]_d - Pa[m]) to the total available power E2 by the total excess value E1.

Number

[0051] In step Sa5, the distribution processing unit 523 calculates a power distribution value Pb[m] for each power storage unit U[m]. That is, each power distribution value Pa[m] is updated to the power distribution value Pb[m]. Specifically, for one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pa[m] exceeds the limit value L[m]_d, the distribution processing unit 523 sets the limit value L[m]_d as the updated power distribution value Pb[m]. Also, for one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pa[m] does not exceed the limit value L[m]_d, the distribution processing unit 523 calculates the updated power distribution value Pb[m] by adding the additional distribution value ΔP[m] to the power distribution value Pa[m]. For the power storage unit U[m] in which the power distribution value Pa[m] and the limit value L[m]_d are equal among the plurality of power storage units U[m], the power distribution value Pa[m] is adopted as the power distribution value Pb[m]. The power distribution value Pb[m] is the command value of the DC power that the power storage device 31 of each power storage unit U[m] should discharge.

[0052] In step Sa6, the distribution processing unit 523 calculates the effective power distribution value P[m] by subtracting the conversion loss x[m] in the power storage unit U[m] from the power distribution value Pb[m] calculated for each power storage unit U[m] (P[m]=Pb[m]-x[m]). That is, as described above, the effective power distribution value P[m] is the command value of the effective power that the power storage unit U[m] should discharge. The operation in which the distribution processing unit 523 calculates the effective power distribution value P[m] when the total DC power command value Cp indicates discharge (Cp>0) is as described above.

[0053] As described above, between each power storage unit U[m] and the synthesis point 11, a power conversion loss X1 by the power conversion facility 21 and a load loss X2 by the load facility 22 occur. As illustrated in FIG. 9, as a result of subtracting the power conversion loss X1 and the load loss X2 from the total value ΣP[m] of the effective power distribution values P[m] calculated by the above procedure, AC power corresponding to the basic command value C0 (=130) is supplied from the management system 100 to the synthesis point 11.

[0054] FIG. 10 is a specific example of the operation of the distribution processing unit 523 when the total DC power command value Cp indicates charging (Cp<0).

[0055] In step Sa1, the distribution processing unit 523 calculates the power distribution value Pa[m] to be distributed to each power storage unit U[m] among the total DC power command value Cp according to the distribution coefficient K[m] of each power storage unit U[m]. Specifically, the distribution processing unit 523 calculates each power distribution value Pa[m] so that each power distribution value Pa[m] has a ratio corresponding to the distribution coefficient K[m]. That is, the distribution processing unit 523 calculates each power distribution value Pa[m] by multiplying the ratio of each distribution coefficient K[m] to the total value ΣK[m] of the plurality of distribution coefficients K[m] (K[1] to K[5]) by the total DC power command value Cp of charging illustrated in FIG. 6, as in the above formula (2).

[0056] The power distribution value Pa[m] calculated in step Sa1 may exceed the charging limit value L[m]_c. When the total DC power command value Cp indicates charging, the case where the power distribution value Pa[m] exceeds the limit value L[m]_c means the case where the power distribution value Pa[m] is below the limit value L[m]_c (Pa[m] < L[m]_c). For example, in FIG. 10, the case where the power distribution value Pa[4] (= -40) of the power storage unit U[4] exceeds the limit value L[4]_c (= -30) and the power distribution value Pa[5] (= -50) of the power storage unit U[5] exceeds the limit value L[5]_c (= -40) is illustrated.

[0057] The distribution processing unit 523 distributes the total excess value E1 obtained by summing the excess value (Pa[m] - L[m]_c) to each of one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pa[m] exceeds the limit value L[m]_c (Sa2 to Sa5).

[0058] Specifically, in step Sa2 of FIG. 10, the distribution processing unit 523 calculates the total excess value E1 by summing the difference between the power distribution value Pa[m] and the limit value L[m]_c (i.e., the excess value) for one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pa[m] exceeds the limit value L[m]_c. In the situation of FIG. 10, "-20", which is the sum of "-10", the excess value (Pa[4] - L[4]_c) of the power storage unit U[4], and "-10", the excess value (Pa[5] - L[5]_c) of the power storage unit U[5], is calculated as the total excess value E1.

[0059] In step Sa3, the distribution processing unit 523 calculates the total available power E2 by summing the difference between the limit value L[m]_c and the power distribution value Pa[m] (i.e., the margin value) for one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pa[m] does not exceed the limit value L[m]_c. In the situation of FIG. 10, "-30", which is the sum of "-20", the margin value of the power storage unit U[4] (L[1]_c - Pa[1]), and "-10", the margin value of the power storage unit U[2] (L[2]_c - Pa[2]), is calculated as the total available power E2.

[0060] In step Sa4, the distribution processing unit 523 calculates an additional distribution value ΔP[m] for one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pa[m] does not exceed the limit value L[m]_c. Specifically, the distribution processing unit 523 calculates each additional distribution value ΔP[m] by the operation of the following mathematical formula (3b). That is, the distribution processing unit 523 calculates the additional distribution value ΔP[m] by multiplying the ratio of each margin value (L[m]_c - Pa[m]) to the total available power E2 by the total excess value E1.

Number

[0061] In step Sa5, the distribution processing unit 523 calculates a power distribution value Pb[m] for each power storage unit U[m]. That is, each power distribution value Pa[m] is updated to the power distribution value Pb[m]. Specifically, the distribution processing unit 523 sets the limit value L[m]_c as the updated power distribution value Pb[m] for one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pa[m] exceeds the limit value L[m]_c. Also, the distribution processing unit 523 calculates the updated power distribution value Pb[m] by adding an additional distribution value ΔP[m] to the power distribution value Pa[m] for one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pa[m] does not exceed the limit value L[m]_c. For a power storage unit U[m] in which the power distribution value Pa[m] is equal to the limit value L[m]_c among the plurality of power storage units U[m], the power distribution value Pa[m] is adopted as the power distribution value Pb[m]. The power distribution value Pb[m] is a command value for the DC power that the power storage device 31 of each power storage unit U[m] should charge.

[0062] In step Sa6, the distribution processing unit 523 calculates an effective power distribution value P[m] by subtracting the conversion loss x[m] in the power storage unit U[m] from the power distribution value Pb[m] calculated for each power storage unit U[m] (P[m]=Pb[m]-x[m]). That is, as described above, the effective power distribution value P[m] is a command value for the effective power that the power storage unit U[m] should charge. The operation of the distribution processing unit 523 to calculate the effective power distribution value P[m] when the total DC power command value Cp indicates charging (Cp < 0) is as described above.

[0063] As described above, between each power storage unit U[m] and the synthesis point 11, a substation loss X1 by the substation equipment 21 and a load loss X2 by the load equipment 22 occur. As illustrated in FIG. 11, as a result of subtracting the substation loss X1 and the load loss X2 from the total value ΣP[m] of the effective power distribution values P[m] calculated by the above procedure, AC power corresponding to the basic command value C0 (=-170) is supplied from the synthesis point 11 to the management system 100.

[0064] FIG. 12 is a flowchart of the overall operation of the control system 40 (hereinafter referred to as "control process"). For example, the control process in FIG. 12 is repeated at a predetermined cycle.

[0065] When the control process starts, the control device 41 (command calculation unit 51) acquires a basic command value C0 (S1). The control device 41 (command calculation unit 51) calculates a total DC power command value Cp by adding power losses including a substation loss X1, a load loss X2, and a conversion loss X3 to the basic command value C0 (S2).

[0066] The control device 41 (command distribution unit 52) calculates an active power distribution value P[m] which is a command value of the power to be distributed to each of a plurality of power storage units U[m] among the total DC power command value Cp (S3). A specific example of the process of calculating the active power distribution value P[m] is as described above with reference to FIGS. 8 and 10. The control device 41 (operation instruction unit 53) instructs each of the plurality of power storage units U[m] of the active power distribution value P[m] of the power storage unit U[m] (S4).

[0067] When the power storage system 30 includes a power storage unit U[m] that responds to DC power in response to a command of DC power, the control device 41 (operation instruction unit 53) may instruct the power storage unit U[m] of the power distribution value Pb[m] calculated for the power storage unit U[m]. Further, when the power storage system 30 includes a power storage unit U[m] that responds to the active power at a point between the transformer 321 and the AC-DC converter 322 in response to an instruction of the active power at that point, the control device 41 (operation instruction unit 53) may instruct the power storage unit U[m] with a value obtained by subtracting the loss of the transformer 321 in the power storage unit U[m] from the power distribution value Pb[m] calculated for the power storage unit U[m].

[0068] As described above, in the first embodiment, the total DC power command value Cp is calculated by adding the conversion loss X3 due to the conversion between the DC power and the AC power that the power storage device 31 discharges or charges, and the substation loss X1 due to the mutual transformation between the substation facilities 21 and the power storage system 30 to the basic command value C0, and the total DC power command value Cp is distributed to each power storage unit U[m]. Therefore, compared with the form in which the basic command value C0 is distributed to each power storage unit U[m] without considering the substation loss X1 and the conversion loss X3, the effective power distribution value P[m] instructed to each power storage unit U[m] can be appropriately calculated. When the basic command value C0 is minute, the influence of the conversion losses (X1 to X3) on the basic command value C0 relatively increases. Therefore, the configuration of the first embodiment in which the substation loss X1 and the conversion loss X3 are taken into account in the basic command value C0 is particularly effective.

[0069] Also, in the first embodiment, for one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pa[m] exceeds the limit value L[m], the total excess value E1 obtained by summing up the excess values is distributed to each of one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pa[m] does not exceed the limit value L[m]. Therefore, while maintaining the synthetic point power at the basic command value C0, the power distributed to each power storage unit U[m] can be suppressed within the range of the limit value L[m].

[0070] 2. Second Embodiment The second embodiment of the present disclosure will be described. For elements whose functions are the same as those in the first embodiment in each aspect exemplified below, the same reference numerals as those in the description of the first embodiment are used, and the detailed description of each is appropriately omitted.

[0071] FIG. 13 is an explanatory diagram regarding the numerical range of the effective power distribution value P[m] in the second embodiment. As illustrated in FIG. 13, in the second embodiment, a first range R1 and a second range R2 (R2_d, R2_c) are defined in the numerical range of the effective power distribution value P[m]. The first range R1 is a range with a predetermined width including the numerical value 0. Specifically, the first range R1 is a range between a threshold value T1_d and a threshold value T1_c (T1_c ≦ P[m] ≦ T1_d). The threshold value T1_d is greater than the threshold value T1_c. The threshold value T1_d is a predetermined positive number indicating the discharge of the power storage unit U[m] (T1_d > 0) and corresponds to the upper limit value of the first range R1. On the other hand, the threshold value T1_c is a predetermined negative number indicating the charge of the power storage unit U[m] (T1_c < 0) and corresponds to the lower limit value of the first range R1.

[0072] The second range R2 is a range adjacent to the first range R1. Specifically, the second range R2 includes a discharge range R2_d and a charge range R2_c. The discharge range R2_d is a range adjacent to the positive side of the first range R1, and the charge range R2_c is a range adjacent to the negative side of the first range R1.

[0073] Specifically, the discharge range R2_d is a range between the aforementioned threshold value T1_d and a predetermined threshold value T2_d (T1_d < P[m] ≦ T2_d). The threshold value T2_d is a positive number greater than the threshold value T1_d (T2_d > T1_d) and corresponds to the upper limit value of the discharge range R2_d. The threshold value T1_d is the lower limit value of the discharge range R2_d. Note that the width |T2_d - T1_d| of the discharge range R2_d is smaller than the width |T1_d - T1_c| of the first range R1. However, a form in which the width of the discharge range R2_d is greater than the width of the first range R1 or a form in which the width of the discharge range R2_d is common to the width of the first range R1 is also assumed.

[0074] On the other hand, the charging range R2_c is a range (T2_c ≤ P[m] < T1_c) between the aforementioned threshold value T1_c and a predetermined threshold value T2_c. The threshold value T2_c is a negative number less than the threshold value T1_c (T2_c < T1_c) and corresponds to the lower limit value of the charging range R2_c. The threshold value T1_c is the upper limit value of the charging range R2_c. Note that the width |T1_c - T2_c| of the charging range R2_c is less than the width |T1_d - T1_c| of the first range R1. However, a form in which the width of the charging range R2_c exceeds the width of the first range R1 or a form in which the width of the charging range R2_c and the width of the first range R1 are common is also assumed. Also, the width of the discharging range R2_d and the width of the charging range R2_c may be the same or different.

[0075] When the effective power distribution value P[m] of each power storage unit U[m] is a positive or negative minute value, there is a problem that numerical values regarding states such as voltage or charge rate cannot be accurately measured for each power storage device 31. The first range R1 is a range including minute values in which the above problems can occur among the numerical ranges of the effective power distribution value P[m]. That is, the first range R1 is expressed as a numerical range to be avoided in operation regarding the effective power distribution value P[m].

[0076] FIG. 14 is a flowchart illustrating the operation of the command distribution unit 52 in the second embodiment. The process of FIG. 14 is executed in step S3 of the control process illustrated in FIG. 12.

[0077] The command distribution unit 52 first calculates a provisional power distribution value Pb[m] of each power storage unit U[m] by the same method as in the first embodiment (S31). Specifically, the command distribution unit 52 calculates an initial power distribution value Pa[m] of the power storage unit U[m] by distributing the total DC power command value Cp according to the distribution coefficient K[m] (Sa1), and calculates the power distribution value Pb[m] of each power storage unit U[m] by distributing the excess of each power distribution value Pa[m] over the limit value L[m] to other power storage units U[m] (Sa2 to Sa5).

[0078] The command distribution unit 52 determines whether any of a plurality of power distribution values Pb[m] calculated for different power storage units U[m] is a value within the first range R1 (S32). When any of the plurality of power distribution values Pb[m] is a value within the first range R1 (S32: YES), the command distribution unit 52 executes a first limiting process (S33). The first limiting process is a process of distributing the power distribution value Pb[m] that is a value within the first range R1 among the other power distribution values Pb[m]. The details of the first limiting process will be described later.

[0079] On the other hand, when none of the plurality of power distribution values Pb[m] is a value within the first range R1 (S32: NO), the command distribution unit 52 determines whether any of the plurality of power distribution values Pb[m] is a value within the second range R2 (discharge range R2_d or charge range R2_c) (S34).

[0080] When any of the plurality of power distribution values Pb[m] is a value within the second range R2 (S34: YES), the command distribution unit 52 executes a second limiting process (S35). The second limiting process is a process of restricting the redistribution from the other power distribution values Pb[m] for the power distribution value Pb[m] that is a value within the second range R2 among the plurality of power distribution values Pb[m]. The details of the second limiting process will be described later.

[0081] When executing the first limiting process (S33) or the second limiting process (S35), the command distribution unit 52 calculates the effective power distribution value P[m] by subtracting the conversion loss x[m] from each power distribution value Pb[m] after each process, similar to step Sa6 exemplified in the first embodiment (S36).

[0082] Also, when a plurality of power distribution values Pb[m] do not fall within the numerical values in the first range R1 or the numerical values in the second range R2 (S34: NO), the command distribution unit 52 calculates the effective power distribution value P[m] by subtracting the conversion loss x[m] from the calculated power distribution value Pb[m] of each power storage unit U[m] (S36). When the effective power distribution value P[m] of each power storage unit U[m] is calculated by the above procedure, the command distribution unit 52 ends the process of FIG. 14.

[0083] The specific procedures of the first limiting process and the second limiting process will be described below. In the following description, as illustrated in FIG. 13, it is assumed that the threshold value T1_d of the first range R1 is 5, the threshold value T1_c of the first range R1 is -5, the threshold value T2_d of the second range R2 is 8, and the threshold value T2_c of the second range R2 is -8.

[0084] [First Limiting Process (S33)] FIG. 15 is an explanatory diagram illustrating the specific procedure of the first limiting process. In FIG. 15, it is assumed that the power distribution value Pb[5] of the power storage unit U[5] among the plurality of power storage units U[m] is a numerical value within the first range R1 (Pb[5] = 5). The power storage unit U[5] in the following description is an example of the "first power storage unit".

[0085] When the first limiting process is started, the command distribution unit 52 changes the limit value L[5]_d of the power storage unit U[5] to 0 (S331). That is, when the power distribution value Pb[m] calculated for the power storage unit U[5] is a numerical value within the first range R1, the command distribution unit 52 changes the limit value L[5]_d of the power storage unit U[5] to 0.

[0086] FIG. 16 is an explanatory diagram of the change in the limit value L[5]_d in the first limiting process. As illustrated in FIG. 16, the command distribution unit 52 changes the limit value L[5]_d of the power storage unit U[5] to 0 over time. That is, the command distribution unit 52 continuously changes the limit value L[5]_d from the default value to 0 from the start point to the end point of the period Ta on the time axis.

[0087] As a result of the limit value L[5]_d being changed to 0, the calculated power distribution value Pb[m] for the power storage unit U[5] exceeds the limit value L[5]_d. Therefore, the command distribution unit 52 distributes the power distribution value Pb[5] of the power storage unit U[5] (that is, the excess of the power distribution value Pb[5] over the limit value L[5]_d) to each power storage unit U[m] (U[1] to U[4]) other than the power storage unit U[5] (S332 to S335). The process of distributing the power distribution value Pb[5] to each power storage unit U[m] is the same as the process from step Sa3 to step Sa5 in the first embodiment.

[0088] Specifically, in step S332, the command distribution unit 52 calculates the total excess value E1 by summing the difference between the power distribution value Pa[m] and the limit value L[m]_d (that is, the excess value) for one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pb[m] exceeds the limit value L[m]_d. In the situation of FIG. 15, among the plurality of power storage units U[m], only the power distribution value Pb[5] of the power storage unit U[5] for which the limit value L[5]_d has been changed to 0 exceeds the limit value L[5]_d. Therefore, the power distribution value Pb[5] of the power storage unit U[5] is calculated as the total excess value E1 (E1 = Pb[5]).

[0089] In step S333, the command distribution unit 52 calculates the total available power E2 by summing the difference between the limit value L[m]_d and the power distribution value Pb[m] (that is, the margin value) for each power storage unit U[m] (U[1] to U[4]) other than the power storage unit U[5] among the plurality of power storage units U[m].

[0090] In step S334, the command distribution unit 52 calculates an additional distribution value ΔP[m] for each power storage unit U[m] (U[1] to U[4]) other than the power storage unit U[5]. Specifically, the command distribution unit 52 calculates each additional distribution value ΔP[m] by the operation of the following mathematical formula (3c). That is, the command distribution unit 52 calculates the additional distribution value ΔP[m] by multiplying the ratio of each margin value (L[m]_d - Pb[m]) to the total available power E2 by the total excess value E1 (the power distribution value Pb[5] of the power storage unit U[5]).

Number

[0091] In step S335, the command distribution unit 52 updates the power distribution value Pb[m] of each power storage unit U[m]. Specifically, the command distribution unit 52 sets the limit value L[m]_d as the updated power distribution value Pb[m] for one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pb[m] exceeds the limit value L[m]_d. For example, as a result of the limit value L[5]_d being changed to 0, the power distribution value Pb[5] of the power storage unit U[5] is updated to 0.

[0092] In addition, the command distribution unit 52 calculates the updated power distribution value Pb[m] by adding the additional distribution value ΔP[m] to the power distribution value Pb[m] for one or more power storage units U[m] among the plurality of power storage units U[m] whose power distribution value Pb[m] does not exceed the limit value L[m]_d. Note that for the power storage unit U[m] where the power distribution value Pb[m] and the limit value L[m]_d are equal among the plurality of power storage units U[m], the calculated power distribution value Pb[m] is maintained. The effective power distribution value P[m] of each power storage unit U[m] is calculated by subtracting the conversion loss x[m] from each power distribution value Pb[m] calculated by the above procedure (S36).

[0093] As described above, in the second embodiment, when the power distribution value Pb calculated for the power storage unit U[5] is a value within the first range R1, the power distribution value Pb[5] is distributed to one or more power storage units U[m] (U[1] to U[4]). That is, the power distribution value Pb[5] of the power storage unit U[5] is changed to 0. Therefore, the possibility that the power distribution value Pb[m] of each power storage unit U[m] becomes a non-zero minute value within the first range R1 can be reduced.

[0094] Also, in the second embodiment, the limit value L[5]_d of the power storage unit U[5] changes over time to 0 over a predetermined time. That is, discontinuous fluctuations in the limit value L[5]_d are suppressed. Therefore, the possibility that the combined point power fluctuates suddenly due to a sharp change in the limit value L[5]_d of each power storage unit U[5] can be reduced.

[0095] [Second Limiting Process (S35)] FIG. 17 is an explanatory diagram illustrating a specific procedure of the second limiting process. In FIG. 17, it is assumed that the power distribution value Pb[5] of the power storage unit U[5] among the plurality of power storage units U[m] is a value within the discharge range R2_d in the second range R2 (Pb[5] = 8). The power storage unit U[5] in the following description is an example of the "second power storage unit".

[0096] When the second limiting process is started, the command distribution unit 52 changes the limit value L[5]_d of the power storage unit U[5] to the already calculated power distribution value Pb[5] at the current time (S351). That is, when the power distribution value Pb[5] calculated for the power storage unit U[5] is a value within the second range R2, the command distribution unit 52 changes the limit value L[5]_d of the power storage unit U[5] to the power distribution value Pb[5].

[0097] FIG. 18 is an explanatory diagram of the change in the limit value L[5]_d in the second limiting process. As illustrated in FIG. 18, the command distribution unit 52 changes the limit value L[5]_d of the power storage unit U[5] to the power distribution value Pb[5] over time. That is, the command distribution unit 52 continuously changes the limit value L[5]_d from the default value to the power distribution value Pb[5] from the start point to the end point of the period Tb on the time axis.

[0098] Similar to the first limiting process (S33), the command distribution unit 52 executes the calculation of the total excess value E1 (S352), the calculation of the total available power E2 (S353), the calculation of the additional distribution value ΔP[m] of each power storage unit U[m] (S354), and the update of the power distribution value Pb[m] of each power storage unit U[m] (S355).

[0099] As described above, since the limit value L[5]_d of the power storage unit U[5] is changed to the power distribution value Pb[5], the difference (i.e., the margin value) between the limit value L[5]_d and the power distribution value Pb[5] in the power storage unit U[5] is 0. Therefore, the additional distribution value ΔP[5] of the power storage unit U[5] is 0. That is, no additional distribution (S355) is performed on the power distribution value Pb[m] that has been calculated for the power storage unit U[5]. As described above, in the second embodiment, since the power storage unit U[5] is excluded from the distribution target of the additional distribution value ΔP[m], additional distribution for the power storage unit U[5] can be suppressed.

[0100] Also, in the second embodiment, the limit value L[5]_d of the power storage unit U[5] changes to the power distribution value Pb[5] over time over a predetermined time. That is, discontinuous fluctuations in the limit value L[5]_d are suppressed. Therefore, it is possible to reduce the possibility that the combined point power fluctuates suddenly due to a sharp change in the limit value L[5]_d of each power storage unit U[5].

[0101] FIG. 19 is an explanatory diagram of the temporal changes of the respective numerical values (Pb[5], L[5]_d) related to the power storage unit U[5] described above. In FIG. 19, the initial power distribution value Pb[5] before the update by the first limiting process or the second limiting process is represented by the symbol Pb[5]_1, and the power distribution value Pb[5] after the update is represented by the symbol Pb[5]_2.

[0102] In FIG. 19, it is assumed that the power distribution value Pb[5]_1 before the update decreases over time to 0 within the positive range until time t3 and then increases over time within the positive range from time t3.

[0103] The power distribution value Pb[5]_1 reaches the threshold value T2_d of the second range R2 at time t1 and then decreases over time within the second range R2. Therefore, after time t1, the limit value L[5]_d changes over time from the initial value L0 to the power distribution value Pb[5]_1. Note that the initial value L0 is a default value set before the process by the first limiting process or the second limiting process.

[0104] The power distribution value Pb[5]_1 reaches the threshold value T1_d of the first range R1 at time t2 and then decreases over time within the first range R1. Therefore, after time t1, the limit value L[5]_d changes over time from the value (power distribution value Pb[m]_1) at time t2 to 0. By setting the limit value L[5]_d to 0, the power distribution value Pb[m]_2 after the update is maintained at 0.

[0105] The change in the power distribution value Pb[5]_1 reverses from decreasing to increasing at time t3. Then, the power distribution value Pb[5]_1 reaches the threshold value T1_d of the first range R1 at time t4 and then increases over time within the second range R2. Therefore, after time t4, the limit value L[5]_d changes over time from the value (=0) at time t4 to the power distribution value Pb[5]_1. Due to the increase in the limit value L[5]_d, the power distribution value Pb[5]_2 changes over time to the power distribution value Pb[5]_1 before the update.

[0106] The power distribution value Pb[5]_1 before the update reaches the threshold value T2_d of the second range R2 at time t5, and thereafter increases with time within the second range R2. Therefore, after time t5, the limit value L[5]_d changes with time up to the initial value L0.

[0107] As described above, according to the second embodiment, it is possible to reduce the possibility that the power distribution value Pb[m]_2 of each power storage unit U[m] becomes a minute value within the first range R1. In the above description, it is assumed that the power distribution value Pb[m] is a positive number (discharge), but the same processing is executed even when the power distribution value Pb[m] is a negative number (charge).

[0108] 3. Third Embodiment FIG. 20 is a block diagram illustrating the configuration of the management system 100 according to the third embodiment. As illustrated in FIG. 20, the management system 100 of the third embodiment includes a power generation facility 23 in addition to the same elements (substation facility 21, load facility 22, power storage system 30, control system 40) as those in the first embodiment (FIG. 1).

[0109] The power generation facility 23 is a distributed power source that generates power using, for example, renewable energy. For example, a solar power generation system that converts solar energy into electricity, a wind power generation system that converts wind energy into electricity, a geothermal power generation system that converts geothermal energy into electricity, a hydroelectric power generation system that converts hydro energy into electricity, or a biomass power generation system that converts biomass energy into electricity, or any other power generation system that uses renewable energy can be used as the power generation facility 23. The power generation facility 23 may be configured by a plurality of power generation systems with different power generation methods.

[0110] In each of the above-described embodiments, the command calculation unit 51 calculates the total DC power command value Cp by adding the power loss (X1 + X2 + X3) including the conversion loss X1, the load loss X2, and the conversion loss X3 to the basic command value C0 as in the above-described formula (1). The command calculation unit 51 of the third embodiment calculates the total DC power command value Cp by adding the active power generated by the power generation facility 23 (hereinafter referred to as "generated active power value Gc") to the basic command value C0 in addition to the power loss (X1 + X2 + X3). Specifically, the command calculation unit 51 calculates the total DC power command value Cp by an operation including addition of the power loss (X1 + X2 + X3) to the basic command value C0 and subtraction of the generated active power value Gc as in the following formula (4). [Number]

[0111] The configuration and operation for calculating the active power distribution value P[m] of each power storage unit U[m] from the total DC power command value Cp are the same as those in the above-described embodiments. According to the third embodiment, even in an environment where the power generation facility 23 is installed in parallel with a plurality of power storage units U[m], the synthetic point power can be maintained at the basic command value C0 with high accuracy.

[0112] 4. Fourth Embodiment FIG. 21 is a block diagram illustrating the configuration of the management system 100 according to the fourth embodiment. As illustrated in FIG. 21, the power adjustment device 32 in each power storage unit U[m] of the fourth embodiment is a DC / DC converter that converts DC power into DC power of another voltage value. That is, each power storage unit U[m] of the fourth embodiment supplies or receives DC power. The conversion loss X3 applied to the calculation of the total DC power command value Cp in the fourth embodiment includes a numerical value obtained by summing the power losses caused by power conversion by the power adjustment device 32 over a plurality of power storage units U[m].

[0113] As illustrated in FIG. 21, an AC / DC converter 24 is installed between the power substation equipment 21 and the power storage system 30. The AC / DC converter 24 is an AC / DC converter that mutually converts DC power and AC power. AC power is exchanged between the AC / DC converter 24 and the power substation equipment 21, and DC power is exchanged between the AC / DC converter 24 and each power storage unit U[m]. In the above configuration, the power conversion loss X1 is a power loss resulting from power conversion by the power substation equipment 21 and the AC / DC converter 24.

[0114] The management system 100 of the fourth embodiment includes a load facility 22a and a load facility 22b. The load facility 22a is installed in parallel with a plurality of power storage units U[m], similar to the load facility 22 of the first embodiment. The load facility 22b is connected between the AC / DC converter 24 and the power substation equipment 21. The load loss X2 of the fourth embodiment is the total value of the power loss in the load facility 22a and the power loss in the load facility 22b.

[0115] Also in the fourth embodiment, similar to the first embodiment, the command calculation unit 51 calculates the total DC power command value Cp by adding the power loss (X1 + X2 + X3) including the power conversion loss X1, the load loss X2, and the conversion loss X3 to the basic command value C0. Note that the power generation facility 23 of the third embodiment may be added to the fourth embodiment. 5. Fifth Embodiment FIG. 22 is a block diagram illustrating the configuration of each power storage unit U[m] in the fifth embodiment. As illustrated in FIG. 65, the power storage unit U[m] of the fifth embodiment includes a load facility 33 in addition to the same elements (power storage device 31, power conditioner 32) as in the previous embodiments. The load facility 33 is various loads that operate by consuming the power supplied from the power conditioner 32. For example, the load facility 33 is a power supply device that generates auxiliary power or control power used within the power storage unit U[m].

[0116] In the conversion loss x[m] of each power storage unit U[m] in the fifth embodiment, in addition to the losses of the transformer 321 and the AC-DC converter 322 (and further line losses), the active power X31 of the load equipment 33 in the power storage unit U[m] is added. That is, the conversion loss X3 in the fifth embodiment includes the total of the active powers X31 of the load equipment 33 in the plurality of power storage units U[m]. The active power X31 of the load equipment 33 is measured by, for example, a measuring instrument (not shown) installed in each power storage unit U[m].

[0117] 6. Modification Example Specific modification modes added to each of the aspects exemplified above are exemplified below. Two or more aspects arbitrarily selected from the following examples may be appropriately combined within a non-conflicting range.

[0118] (1) In the second embodiment, a form in which the first range R1 and the second range R2 (R2_d, R2_c) are fixed ranges is exemplified, but the first range R1 or the second range R2 may be a variable range. For example, the control device 41 (command distribution unit 52) variably controls the range width of the first range R1 or the second range R2 by changing each threshold value (T1_d, T2_d, T1_c, T2_c) in FIG. 12 according to an instruction from the administrator of the management system 100.

[0119] (2) In the second embodiment, a form in which the threshold value T2_d exceeds the threshold value T1_d is exemplified. In the above form, a discharge range R2_d (second range R2) having a range width corresponding to the difference between the threshold value T2_d and the threshold value T1_d is ensured. However, the threshold value T2_d may be set to a numerical value equal to the threshold value T1_d. When the threshold value T2_d and the threshold value T1_d are equal, the discharge range R2_d disappears (range width = 0). Therefore, the second limit process caused by the power distribution value Pb[m] being a value within the discharge range R2_d is not executed.

[0120] Also, in the second embodiment, a form in which the threshold value T2_c is lower than the threshold value T1_c was exemplified. In the above form, a charging range R2_c (second range R2) with a range width corresponding to the difference between the threshold value T1_c and the threshold value T2_c is ensured. However, the threshold value T2_c may be set to the same numerical value as the threshold value T1_c. When the threshold value T2_c and the threshold value T1_c are equal, the charging range R2_c disappears (range width = 0). Therefore, the second limiting process caused by the power distribution value Pb[m] being a value within the charging range R2_c is not executed.

[0121] Furthermore, the threshold value T1_d, which is the upper limit value of the first range R1, and the threshold value T1_c, which is the lower limit value, may be set to the same numerical value. When the threshold value T1_d and the threshold value T1_c are equal, the first range R1 disappears (range width = 0). Therefore, the first limiting process caused by the power distribution value Pb[m] being a value within the first range R1 is not executed.

[0122] As shown in the above examples, in a state where each threshold value is set to a different numerical value (T2_c < T1_c < T1_d < T2_d), as exemplified in the second embodiment, the first limiting process and the second limiting process are executed according to the relationship between the first range R1 or the second range R2 (R2_d, R2_c) and the power distribution value Pb[m]. On the other hand, in a state where each threshold value is set to the same numerical value (T2_c = T1_c = T1_d = T2_d = 0), the first limiting process and the second limiting process are invalidated. As can be understood from the above description, the control device 41 (command distribution unit 52) operates in either a first operation mode (T2_c < T1_c < T1_d < T2_d) in which the first limiting process and the second limiting process are enabled, or a second operation mode (T2_c = T1_c = T1_d = T2_d = 0) in which the first limiting process and the second limiting process are invalidated.

[0123] The operation mode of the control device 41 is selected, for example, according to an instruction from the administrator of the management system 100. When the first operation mode is instructed, the control device 41 enables the first limit process and the second limit process by setting each threshold value to different numerical values (T2_c < T1_c < T1_d < T2_d). On the other hand, when the second operation mode is instructed, the control device 41 disables the first limit process and the second limit process by setting each threshold value to equal numerical values (T2_c = T1_c = T1_d = T2_d = 0).

[0124] (3) Two or more embodiments selected from the plurality of embodiments exemplified above may be arbitrarily combined. The configurations exemplified in each of the above embodiments may be implemented without assuming the configurations of other embodiments.

[0125] (4) The functions of the control system 40 according to the above-described embodiment are realized, as described above, by the cooperation of one or more processors constituting the control device 41 and the program stored in the storage device 42. The programs exemplified above can be provided in a form stored in a computer-readable recording medium and installed in a computer. The recording medium is, for example, a non-transitory recording medium, and an optical recording medium (optical disk) such as a CD-ROM is a preferred example, but any known form of recording medium such as a semiconductor recording medium or a magnetic recording medium is also included. Note that the non-transitory recording medium includes any recording medium except a transitory, propagating signal, and does not exclude a volatile recording medium. Also, in a configuration where a distribution device distributes a program via a communication network, the recording medium that stores the program in the distribution device corresponds to the non-transitory recording medium described above.

[0126] (5) The description "the nth" (n is a natural number) in this application is used only as a formal and convenient label for distinguishing each element in notation and has no substantial meaning. Therefore, there is no room for limited interpretation of the position or order of each element based on the notation "the nth".

[0127] 7. Supplementary Note From the forms exemplified above, for example, the following configuration can be understood.

[0128] A control system according to one aspect (Aspect 1) of the present disclosure is a control system that controls a power storage system that adjusts power at a connection point with a power grid by a plurality of power storage units including a power storage device that discharges and charges DC power. The control system includes a command calculation unit that calculates a total DC power command value that is the total value of the power that the power storage devices in the plurality of power storage units should discharge or charge, a command distribution unit that calculates a power distribution value to be distributed to each of the plurality of power storage units from the total DC power command value, and an operation instruction unit that instructs each of the plurality of power storage units of the power distribution value of the power storage unit. When the power distribution value calculated for the first power storage unit among the plurality of power storage units is a value within a first range, the command distribution unit distributes the power distribution value to one or more power storage units other than the first power storage unit among the plurality of power storage units. In the above aspect, when the power distribution value calculated for the first power storage unit is a value within the first range, the power distribution value is distributed to one or more power storage units. That is, the power distribution value of the first power storage unit is changed to 0. Therefore, the possibility that the power distribution value of each power storage unit becomes a minute value can be reduced.

[0129] In a specific example of Mode 1 (Mode 2), the command distribution unit sets a limit value for each of the plurality of power storage units, and sums up the excess values for one or more power storage units among the plurality of power storage units whose power distribution value exceeds the limit value of the power storage unit, and distributes the total excess value to each of one or more power storage units among the plurality of power storage units whose power distribution value does not exceed the limit value of the power storage unit. When the calculated power distribution value for the first power storage unit is a value within the first range, the limit value of the first power storage unit is changed to 0. In the above aspect, while maintaining the total DC power command value, the power distributed to each power storage unit can be suppressed within the range of the limit value. Also, as a result of the limit value of the first power storage unit among the plurality of power storage units being changed to 0 because the power distribution value is a value within the first range, the power distribution value of the first power storage unit is distributed to other power storage units. Therefore, the possibility that the power distribution value of each power storage unit becomes a minute value can be reduced.

[0130] In a specific example of Mode 2 (Mode 3), the command distribution unit changes the limit value of the first power storage unit to 0 over time. In the above aspect, the limit value of the first power storage unit changes to 0 over time over a predetermined time. That is, discontinuous fluctuations in the limit value are suppressed. Therefore, the possibility that the active power at the synthesis point fluctuates suddenly due to a sharp change in the limit value of each power storage unit can be reduced.

[0131] In a specific example of Mode 2 or Mode 3 (Mode 4), when the calculated power distribution value for the second power storage unit among the plurality of power storage units is a value within a second range adjacent to the first range, the command distribution unit changes the limit value of the second power storage unit to the power distribution value. In the above aspect, for the second power storage unit among the plurality of power storage units whose power distribution value is a value within the second range, the limit value is changed to the power distribution value, so the power distribution value of the second power storage unit does not exceed the limit value. That is, the second power storage unit is excluded from the distribution target of the excess of the power distribution value over the limit value of each power storage unit. As described above, additional distribution for the second power storage unit can be suppressed.

[0132] In a specific example of Mode 4 (Mode 5), the command distribution unit changes the limit value of the second power storage unit to the power distribution value over time. In the above aspects, the limit value of the second power storage unit changes to the power distribution value over time over a predetermined period. That is, discontinuous fluctuations in the limit value are suppressed. Therefore, it is possible to reduce the possibility that the active power at the synthesis point fluctuates suddenly due to a sharp change in the limit value of each power storage unit.

[0133] In a specific example of any one of Modes 1 to 5 (Mode 6), the command calculation unit calculates the total DC power command value by adding power losses including conversion losses due to conversion between the DC power and the AC power and transformation losses due to transformation between the power conversion equipment between the power storage system and the synthesis point and the power storage system to the basic command value of the active power. In the above aspects, the total DC power command value is calculated by adding power losses including conversion losses due to conversion between the DC power and the AC power for which the power storage device discharges or charges and transformation losses due to transformation between the power conversion equipment and the power storage system (that is, losses generated by transformation between the AC voltage between the power storage system and the power conversion equipment and the synthesis point voltage at the synthesis point) to the basic command value, and the total DC power command value is distributed to each power storage unit. Therefore, compared with a form in which the basic command value is distributed to each power storage unit without considering the conversion losses between the DC power and the AC power and the transformation losses between the power storage system and the power conversion equipment, the effective power distribution value instructed to each power storage unit can be appropriately calculated. When the basic command value is minute, the influence of the conversion losses and the transformation losses on the basic command value relatively increases, and thus the configuration of the present disclosure in which the conversion losses and the transformation losses are taken into account in the basic command value is particularly effective.

[0134] A management system according to one aspect (Aspect 7) of the present disclosure includes a power storage system that adjusts active power at a connection point with a power grid by a plurality of power storage units including power storage devices that discharge and charge DC power, and a control system that controls the power storage system. The control system includes a command calculation unit that calculates a total DC power command value that is the total value of the power that the power storage devices in the plurality of power storage units should discharge or charge, a command distribution unit that calculates a power distribution value to be distributed to each of the plurality of power storage units from the total DC power command value, and an operation instruction unit that instructs each of the plurality of power storage units of the power distribution value of the power storage unit. When the power distribution value calculated for the first power storage unit among the plurality of power storage units is a value within a first range, the command distribution unit distributes the power distribution value to one or more power storage units other than the first power storage unit among the plurality of power storage units.

Explanation of Signs

[0135] 100… Management system, 10, 10a, 10b… Power grid, 11, 11a, 11b… Connection point, 21, 21a, 21b… Substation equipment, 22, 22a, 22b… Load equipment, 23… Power generation equipment, 24… AC-DC converter, 30… Power storage system, 31… Power storage device, 32… Control device, 33… Load equipment, 321… Transformer, 322… AC-DC converter, 40… Control system, 41… Control device, 42… Storage device, 43… Transceiver, 51… Command calculation unit, 52… Command distribution unit, 521… Coefficient setting unit, 522… Limit value setting unit, 523… Distribution processing unit, 53… Operation instruction unit.

Claims

1. A control system for controlling a power storage system that adjusts power at a combination point with a power grid by using a plurality of power storage units including a power storage device that discharges and charges DC power, comprising: a command calculation unit that calculates a total DC power command value that is a total value of power to be discharged or charged by the power storage devices in the plurality of power storage units; a command allocation unit that calculates a power allocation value to be allocated to each of the plurality of power storage units from the total DC power command value; an operation instruction unit that instructs each of the plurality of power storage units on a power allocation value of the power storage unit; When a power allocation value calculated for a first power storage unit among the plurality of power storage units is a numerical value within a first range, the command allocation unit allocates the power allocation value to one or more power storage units other than the first power storage unit among the plurality of power storage units. Control system.

2. The command distribution unit includes: setting a limit value for each of the plurality of power storage units; allocating a total excess value obtained by adding up the excess values ​​of one or more power storage units among the plurality of power storage units whose power allocation values ​​exceed the limit value of the power storage unit to each of one or more power storage units among the plurality of power storage units whose power allocation values ​​do not exceed the limit value of the power storage unit; When the power allocation value calculated for the first power storage unit is a value within the first range, the limit value of the first power storage unit is changed to 0. The control system of claim 1.

3. The command distribution unit changes the limit value of the first power storage unit to 0 over time. The control system of claim 2.

4. The command distribution unit includes: When a power allocation value calculated for a second power storage unit among the plurality of power storage units is a value within a second range adjacent to the first range, the limit value of the second power storage unit is changed to the power allocation value. The control system of claim 2.

5. The command allocation unit changes the limit value of the second power storage unit to the power allocation value over time. The control system of claim 4.

6. The command calculation unit calculates the total DC power command value by adding a power loss including a conversion loss due to conversion between the DC power and the AC power and a transformation loss due to a mutual transformation between the power storage system and a substation equipment between the power storage system and the combining point to a basic command value of power at the combining point. The control system of claim 1.

7. a power storage system that adjusts active power at a combination point with a power grid by using a plurality of power storage units including a power storage device that discharges and charges DC power; A control system for controlling the power storage system, The control system includes: a command calculation unit that calculates a total DC power command value that is a total value of power to be discharged or charged by the power storage devices in the plurality of power storage units; a command allocation unit that calculates a power allocation value to be allocated to each of the plurality of power storage units from the total DC power command value; an operation instruction unit that instructs each of the plurality of power storage units on a power allocation value of the power storage unit; When a power allocation value calculated for a first power storage unit among the plurality of power storage units is a numerical value within a first range, the command allocation unit allocates the power allocation value to one or more power storage units other than the first power storage unit among the plurality of power storage units. Management system.

Images