JPH08140285A - Power storage system - Google Patents

Abstract

PURPOSE: To raise energy conversion efficiency by adjusting the discharging power from a secondary battery, according to the parameter value found by a parameter means. CONSTITUTION: A power control system 29 makes either secondary cell module 7a (7b) being decided according to priority charging or discharging electricity, and in the case that the power is insufficient with only the power discharged from the secondary cell module 7a (7b) higher in priority, it makes the secondary cell module 7a (7b) lower in priority discharging electricity. In this case, the power control system 29 adjusts the output (discharging power) from the secondary cell module 7a (7b), based on the magnitude relation with the parameter (for example, discharged depth) found by a parameter means. For example, in the region where the inner resistance of the secondary cell is large, the discharging power is made small to suppress the power loss. Hereby, the energy conversion efficiency of the secondary cell modules 7a and 7b can be raised.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power storage system using a secondary battery.

[0002]

2. Description of the Related Art Electric power storage systems are used for load leveling and peak cutting of grid power, and for stabilizing grid frequency and grid voltage.

In recent years, an electric power storage system using a secondary battery module has been developed. FIG. 20 shows an outline of a power storage system using a secondary battery and its usage pattern.
Will be explained.

The electric power generated by a power source (for example, a nuclear power plant or a thermal power plant) 1 of the grid which is the basis of the grid power is
It is transformed and adjusted at the distribution substation 2 and supplied to the customers of the system load group 3. And the power storage and distributed power supply system 2
0 is connected to the distribution system 4 via a circuit breaker 5 and an AC voltage transformer 6.

The power storage / dispersed power supply system 20 includes a battery module 7 formed by connecting a plurality of secondary batteries in series and parallel.
And a power control unit 12, and a power conversion unit 11 that performs alternating / direct reversible conversion of power. When the power of the distribution system 4 is insufficient, the DC power discharged from the secondary battery module 7 is converted into AC by the power conversion unit 11 and supplied to the system. On the contrary, when the system power becomes excessive at night or the like, the AC power sent from the power distribution system 4 is converted into the DC power by the power conversion unit 11, and the battery module 7 is charged.

[0006] A hybrid type power storage system has also been proposed in which the system power is stabilized in combination with a fuel cell system. For example, Japanese Patent Laid-Open No. 63-45765 discloses a system in which a secondary battery and a fuel cell system are connected in parallel on the DC side. The system is
Except when the output shortage of the fuel cell is to be compensated, the secondary cell is designed to supply electric power to the load while performing floating charging such that the secondary cell is in a charged state.

The secondary battery used in such a power storage system is required to have a large energy density and a small charge / discharge loss. Sodium-sulfur secondary batteries have been attracting attention as one that meets such requirements.
Currently, its development is energetically continued.

It is known that the sodium-sulfur battery has a maximum value due to an increase in internal resistance R at the time of discharge in a high discharge depth region (see FIG. 3). For such characteristics, see, for example, J. Electrochem So
c. , Vol. 136, No. 7, P1962, Jul
y 1989.

In the figure, "depth of discharge" means the total amount of electric power (discharge capacity) that can be discharged from the battery by starting discharging from the fully charged state, and the electric power already discharged at that time. It is the ratio to the quantity. Alternatively, it is the ratio of the time required for the battery voltage to drop from the fully charged state to a certain voltage after the start of discharging and the time that has already elapsed by that point.

[0010]

Assuming that the battery voltage is E, the battery current is I, and the internal resistance is R, the charging / discharging electric energy W and the energy conversion efficiency η are expressed by the following formulas 1, 2 and 3. It

[0011]

[Equation 1] Charging power amount Wc = ∫I · E dt + ∫I ² · R dt

[0012]

[Equation 2] Discharge power amount Wd = ∫I · E dt−∫I ² · R dt

[0013]

[Equation 3] Energy conversion efficiency η = Discharge power amount Wd / Charge power amount Wc As can be seen from Formula 3, when the charge power amount Wc is considered to be constant, the energy conversion efficiency changes according to the output of the discharge power. . Here, the charging power amount Wc
= Considering the case where the rated power amount Ws (see Formula 4),
The energy conversion efficiency ηs is shown by the following Expression 5.
The power loss amount Wp1 is shown by the following equation 6.

[0014]

[Equation 4] Rated electric energy Ws = ∫I · Eocv dt Eocv: Open circuit voltage

[0015]

[Equation 5] Energy conversion efficiency ηs on the basis of rated power = Discharge power amount Wd / Rated power amount Ws

[0016]

## EQU00006 ## Power loss amount Wp1 = Rated power amount Ws-Discharge power amount Wd The power loss amount Wp1 (see Formula 6) corresponds to the second term on the right side of Formula 2. The smaller the internal resistance R,
The energy conversion efficiency ηs based on the rated power becomes high.
In other words, the amount of energy loss becomes large in the discharge in the region where the internal resistance R is high. If a constant current is discharged regardless of the depth of discharge, the efficiency ηs decreases. In order to reduce the amount of energy loss and increase the energy conversion efficiency ηs, in the sodium-sulfur battery,
It is preferable to charge and discharge only in the low resistance region where the depth of discharge is about 50% or less (see FIG. 3).

In addition, the electromotive force of a battery generally decreases in a region where the depth of discharge is high. In order to always supply a constant power to the outside (constant power operation), the output current must be increased in the region where the depth of discharge is high. Therefore, such constant power operation was supposed to further increase the amount of energy loss (see FIG. 21).

Further, there is a problem that the larger the battery module, the larger the amount of energy loss due to the internal resistance.

However, the conventional system does not perform the output control in consideration of such changes in the internal resistance and the electromotive force depending on the depth of charge and discharge, resulting in a decrease in energy conversion efficiency.

As another problem, the conventional system is
There was not enough consideration given to emergency situations. For example, if the load changes abruptly due to an accident or the like, the frequency of the AC power supplied to the grid changes abruptly. In such a case, the grid frequency can be stabilized by adjusting the effective power charged and discharged by the secondary battery. However, in the conventional system, the charge / discharge capacity of the secondary battery is not always sufficient. I could not deal with such a situation when I was approaching the end of charge and discharge.

This problem was also the same in the conventional hybrid system. Changing the operating state of the fuel cell system to cope with a sudden change in load leads to a significant decrease in the life of the fuel cell equipment. For example, the pressure balance between the anode and the cathode is disturbed, and the electrolyte plate is damaged or deteriorated. Further, since an excessive amount of unreacted fuel gas is sent to the burner of the reformer, the reformer temperature abnormally overheats, resulting in deterioration of the reforming catalyst and damage to the reformer.

As a method for coping with a situation where the load is small, for example, Japanese Patent Laid-Open No. 63-276877 discloses a technique of controlling the output of the fuel cell according to the charge amount of the secondary cell.

However, it is also conceivable that when the load reaches near the end of charging at a light load such as at night, the system may be disconnected from the system due to a system fault such as a ground fault. In such a case,
Since the secondary battery cannot be charged, the output of the fuel cell must be temporarily stopped. Unlike a secondary battery, a fuel cell, once stopped, requires a start-up time to increase its output again. Further, there is a problem that the operating rate of the fuel cell device also decreases.

In the conventional hybrid type system, charging / discharging of the secondary battery could not be performed independently for each battery module. Therefore, it is impossible to always secure a chargeable / dischargeable area.

It is an object of the present invention to provide an electric power storage / dispersed power supply system which can sufficiently cope with both steady operation and emergency.

An object of the present invention is to provide a power storage distributed power supply system which can maximize energy conversion efficiency.

[0027]

The present invention has been made in order to achieve the above-mentioned object, and increases the output current (output power) in the region where the internal resistance is low, and increases the output current (output power) in the region where the internal resistance is high. By reducing the electric power), the energy conversion efficiency η (discharge energy / charge energy) of the battery module is increased. The decrease in output power is compensated by using a plurality of battery modules in an appropriate combination.

The structure of the present invention will be described in more detail below.

The first aspect of the present invention is 1 or 2
A secondary battery module including the above secondary battery; parameter means for obtaining a value of a certain parameter (hereinafter referred to as “parameter value”) having a correlation with the internal resistance of the secondary battery; There is provided a power storage system comprising: a control unit that adjusts discharge power from the secondary battery module according to the obtained parameter value.

The control means includes a reference value of the parameter determined based on the relationship with the internal resistance, and the adjustment is based on the magnitude relationship between the reference value and the parameter value obtained by the parameter means. It is preferable that it is carried out.

It is preferable that the adjustment is to reduce the discharge power in a region where the internal resistance is high.

The parameter is preferably the depth of discharge of the secondary battery.

It is preferable that the control means discharges and / or charges the secondary battery module within a predetermined range of the depth of discharge.

A plurality of secondary battery modules arranged in parallel with each other and capable of controlling charging and discharging independently of each other are provided, and the control means has the secondary battery predetermined for each of charging and discharging. It is preferable that a priority level is provided between the modules and the charging and discharging are performed according to the priority level.

The control means may allow the secondary battery module having a low priority level to discharge when the power is insufficient only by the electric power discharged from the secondary battery module having a high priority level. preferable.

According to a second aspect of the present invention, in the method of operating a power storage system using a secondary battery, the internal resistance of the secondary battery is directly / or indirectly determined, and the internal resistance is determined according to the magnitude of the internal resistance. Thus, there is provided a method of operating a power storage system, which comprises adjusting at least one of the output power and the input power of the secondary battery.

[0037]

The control means causes any of the secondary battery modules determined according to the priority level to be charged and discharged. Further, when the electric power discharged from the secondary battery module having a high priority level is insufficient, the secondary battery module having a low priority level is caused to discharge. In this case, the control unit adjusts the output (discharge power) from the secondary battery module based on the magnitude relation between the reference value and the value of the parameter (for example, the depth of discharge) obtained by the parameter unit. For example, the discharge power is reduced in the region where the internal resistance of the secondary battery is high. This allows
Power loss can be suppressed.

Further, usually, the control means causes the secondary battery module to be discharged and / or charged only when the depth of discharge is within a predetermined range. This allows
Usually, a certain fixed capacity for charging and discharging is always secured, and it becomes possible to deal with an emergency.

[0039]

Embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1] FIG. 1 shows an outline of a power storage distributed power supply system of this embodiment and a power supply system using the same.

The power generated by a power source (for example, a nuclear power plant or a thermal power plant) 1 which is the base of the grid power is transformed and adjusted by the distribution substation 2 and supplied to the customers of the grid load group 3. . The power storage / dispersion power supply system 19 of the present embodiment is connected to the power distribution system line 4 via the breaker 5 and the AC voltage transformer 6.

The power storage and distributed power supply system 19 includes secondary battery modules 7a and 7b, battery auxiliary equipment 70, current / voltage detectors 9a and 9b, and switches 10a and 10b.
Power converters 11a and 11b and power control system 29
And are included.

Hereinafter, the secondary battery module 7a and the secondary battery module 7b are collectively referred to simply as "secondary battery module 7". The same applies to the current / voltage detector 9 and the like. Further, the secondary battery module 7a and the secondary battery module 7b may be simply referred to as "module A" and "module B", respectively.

The secondary battery module 7 is for storing electric power, and in this embodiment, it is constituted by connecting sodium-sulfur secondary batteries in series and parallel. The type of secondary battery and the number of modules used are not limited to these. However, it goes without saying that it is necessary to change the contents of the operation control described later according to the type and characteristics of the battery used. The secondary battery modules 7a and 7b can be charged and discharged independently of each other. Therefore, for example, it is possible to charge only the secondary battery module 7a.

The battery auxiliary equipment 70 is a heat insulating container for accommodating the secondary battery module 7, a heater or the like for maintaining the operating temperature of the battery. In this embodiment, the battery auxiliary equipment 70 includes the secondary battery module 7a and the secondary battery module 7
However, it may be provided independently depending on the scale of the battery module.

The power converter 11 is the secondary battery module 7
It is for adjusting the charging / discharging electric power and for AC / DC conversion. The electric power is adjusted by changing the current value. Therefore, the reduction of the output power, which will be described later, directly leads to the reduction of the current value. When the secondary battery module 7 is charged, the AC power supplied from the power distribution system line 4 is converted into DC power, and conversely, when the secondary battery module 7 is discharged, the DC power released from the secondary battery module 7 is converted into AC power. Convert to electricity. These operations are controlled according to the AC / DC switching command 392 and the power setting signal 393 input from the power control system 29. The power converter 11a and the power converter 11b can be controlled independently of each other.

The current / voltage detector 9 is for detecting a current value and a voltage value during charging / discharging of the secondary battery module 7. The current / voltage detector 9 is connected between the secondary battery module 7 and the power converter 11. Electric current
The voltage detector 9 outputs the measurement result to the power control system 29 as the detection signal 400. These data are used for calculation of the amount of electric power and the like in the power control system 29 (particularly, the operation plan creation support means 14 described later).

The switch 10 includes a two-battery module 7,
It is for opening and closing an electric circuit with the distribution system line 4. The switch 10 is configured to operate according to a circuit switching command signal 391 input from the power control system 29. The switch 10a and the switch 10b are configured to be controllable independently of each other.

The power control system 29 is for monitoring and controlling the entire power storage and distributed power supply system 19.
The power control system 29 is connected to the current / voltage detector 9, the switch 10, the power converter 11, and the battery auxiliary equipment 70 by a communication line. In this embodiment, the power control system 29 is composed of hardware such as a microprocessor and a memory, and software (program, data) stored in the memory. Details of the power control system 29 will be described below with reference to FIG.

Functionally, the power control system 29 has a basic data storage means 36, an input means 37, an operation plan creation support means 14, an operation data storage means 35, an operation plan storage means 15, a system protection determination means 12, and an electric power. Control means 39
And so on.

The basic data storage means 36 stores basic data indicating the relationship between the battery characteristics of the secondary battery module 7 (for example, internal resistance, open circuit voltage, current-voltage) and the depth of discharge. However, in order to achieve the purpose of this embodiment (reduction of power loss due to output regulation), at least
It suffices that the basic data includes two relationships, that is, the relationship between the depth of discharge and the internal resistance, and the relationship between the depth of discharge and the circuit voltage. The characteristics of the sodium-sulfur battery including the basic data are shown in FIG.

The input means 37 is for the system administrator to input an instruction to the system when preparing an operation plan. The "operation plan" here is the power load distribution between the secondary battery module 7a and the secondary battery module 7b, the charge / discharge cutoff voltage, and the like. In this embodiment, the input means 37 includes a display device, a keyboard, a mouse and the like. Various simulation results, which will be described later, and the like are displayed on the display device. Therefore, the system administrator is configured to input these while watching the display.

The operation plan creation support means 14 has a function of calculating the depth of discharge, the amount of discharged power, the energy conversion efficiency, etc. of the secondary battery module 7. It also has the function of performing various simulations in order to assist the system administrator in creating an operation plan. Hereinafter, each function will be described in detail.

The depth of discharge and the amount of discharge electric power are obtained by substituting actually measured data (detection signal 400 of the current / voltage detector 9) into the following formulas 7 to 9. further,
The obtained depth of discharge and the like are stored in the operation data storage means 35. The operation data storage means 35 is for storing the usage history of the secondary battery module (for example, the number of cycles, the cumulative energization amount, etc.).

[0055]

[Equation 7] Discharge capacity C (Ah) = ∫i (t) dt

[0056]

[Equation 8] Depth of discharge D (%) = C / C ₀

[0057]

[Equation 9] Discharge power amount Wd (Wh) = ∫i (t) · E
(T) dt−∫i ² (t) · R (t) dt C ₀ : Rated discharge capacity (Ah) i (t): Current value E (t): Voltage R (t): Internal resistance Energy conversion efficiency ηc And, the loss (1−ηc) is calculated based on the measured electric energy after the operation is completed. The calculation result is displayed on the operation control screen of the input means 37.

The simulation of the voltage characteristics, the operating efficiency, etc. is performed using the constraint conditions input from the input means 37, the basic data (see FIG. 3), and the equations (4) to (11).

[0059]

[Equation 10] P (D) = I (D) · Eocv (D) −I
² (D) / R (D)

[0060]

[Equation 11] E (D) = I (D) · R (D) P (D): Output power at discharge depth D I (D): Current at discharge depth D Eocv (D): Open circuit voltage at discharge depth D R (D): Internal resistance at the depth of discharge D E (D): Battery voltage at the depth of discharge D The operation plan (plan of load distribution between modules A and B) is checked by the system administrator while looking at the results of these simulations. , It is constructed according to one's own judgment. For example, by obtaining the depth of discharge of the module A at that time (or after discharging a certain amount of electric power) by the simulation, the module A,
The timing of changing the output power of B (Note: the depth of discharge of 50% described later for module A corresponds to this) can be included in the operation plan as the actual operation switching “time”. The operation plan thus created is stored in the operation plan storage means 15 (signal 1).
41). The operation plan (or the method of determining the plan) actually defines the content of the operation control of the secondary battery module according to the depth of discharge, which is the greatest feature of this embodiment. Therefore, the operation plan will be described later in detail together with the operation description.

In this embodiment, the operation plan creation support means 14 corresponds to the "parameter means" in the claims. The “control means” is realized by the entire power control system 29 (in particular, the power control means 39).

The system protection judging means 12 is for monitoring whether or not there is an abnormality in the power supply system (FIG. 1).
A signal 142 input from the operation planning support means 14
And the detection result (signal 380) of the system monitor unit 13,
The presence or absence of abnormality is determined by comparison. Then, the presence / absence of abnormality and, if there is abnormality, the content thereof is output to the power control means 39 as the determination signal 121. The system monitor unit 13 detects current and voltage in the distribution system line 4. Also, signal 1
Reference numeral 42 indicates voltage, current, electric energy, depth of discharge, and the like.

The power control means 39 is a battery auxiliary equipment 70,
It is for controlling the switch 10 and the power converter 11. The power control means 39 outputs an opening / closing operation command 391 to the switch 10. Similarly, the power converter 11 has an AC / DC switching command 392 and a power setting signal 393.
The auxiliary equipment control signal 394 is output to the battery auxiliary equipment 70. The switch 10 and the like are controlled by these control signals 391.
˜394 to operate.

Normally, the power control means 39 controls the control signal 3 according to the operation plan stored in the operation plan storage means 15.
91 to 394 are output. However, the determination signal 121
When an abnormal occurrence is notified by the, special control is performed to cope with this. For example, when the fluctuation range of the power or frequency in the distribution system line 4 is equal to or more than a predetermined value, the switch 10 is switched to the open state. Further, even when the voltage of the secondary battery module 7 reaches a predetermined cut voltage or a discharge depth, the same operation is performed to prevent overcharging and discharging. It should be noted that the power control means 39 itself has in advance information that defines the contents of special control in the event of such an abnormality.

Next, an example of the operation plan and the criteria for determining the operation plan in the electric power storage and distributed power supply system 19 of this embodiment will be described with reference to FIG. The power demand PL of the system load group 3 is satisfied by both the power supplied by the power storage distributed power supply system 19 and the power Po supplied from the system power supply 1. However, the electric power Po is not related to the electric power storage / distributed power supply system 19 of the present embodiment, and therefore its explanation is omitted.

Here, a constant power (here, P
A case of outputting s (W) will be described as an example. Further, description will be made assuming that the specifications of the modules A and B are as follows.

Module A: Rated power amount = Ws (Wh) Rated output power = Ps (W) Discharge efficiency during rated operation ηs = 70% Module B: Rated power amount = Ws / 2 (Wh) Rated output power = Ps (W) Discharge efficiency during rated operation ηs = 70% Module A has a depth of discharge of 50% (this corresponds to the "reference value" of the parameter in the claims). , Rated power Ps
Drive at (W). And in the depth of discharge after that,
Operate with output power of 0.3 Ps (30% of rated power). This is because in the region where the depth of discharge is high (here, 50% or more), the internal resistance increases (see FIG. 3), so that the output power is reduced to reduce the power loss. As described above, the output power is adjusted by changing the current value.

On the other hand, the module B operates while the module A is operating at the rated power Ps (that is, the module A
When the depth of discharge is less than 50%), no electric power is output. The output power of module A is 0.3 for module B.
When Ps is set (that is, when the depth of discharge exceeds 50%), the operation is performed with the output power of 0.7 Ps (70% of the rated power). The output power of the module B is always 0.7 Ps regardless of the depth of discharge of the module B itself.

By carrying out such load distribution, even when the output power of the module A is 0.3 Ps, the power storage / dispersed power supply system 19 as a whole outputs constant power (= rated power Ps). You can continue.

Output power of each of the modules A and B described here (module A: Ps, 0.3 Ps, module B:
0.7 Ps) is the maximum value of the output power in the discharge depth region. Needless to say, the output power of the modules A and B is appropriately reduced when the power demand is small and the output power that should be output by the power storage distributed power supply system 19 is smaller than Ps.

The output power is cut down preferentially to the module B. Maximum output power for each depth of discharge (P
s, 0.3 Ps), the module A is always prioritized to be discharged within a range not exceeding s, 0.3 Ps). For example, in the area where the depth of discharge of the module A is 80%, the output power required for the entire power storage and distributed power supply system 19 is 0.9.
Consider the case of Ps. In this case, the output power of module A remains 0.3Ps and module B
Only the output power of is reduced to 0.6 Ps.

Next, the operation under the above operation plan will be described with reference to FIGS. 4 and 5.

The power control means 39 operates the power converter 11 and the like in accordance with the operation plan to control the output power of the modules A and B.

The power control means 39 outputs a power setting signal 393 having the content of output power Ps to the power converter 11a. On the other hand, the power converter 11b outputs 0
The power setting signal 393 having the contents described below is transmitted. The current of module A is initially kept almost constant (see FIG. 4). This is because in the region where the depth of discharge is shallow, the voltage does not drop and the internal resistance does not increase.

When the depth of discharge exceeds 50% in the operation plan, the power control means 39 instructs the power converter 11a to reduce the output power from Ps to 0.3 Ps. The power converter 11a corresponds to the module A
Current is once reduced. However, in the subsequent depth of discharge region, the voltage decreases and the internal resistance increases, so the power converter 11a gradually increases the current value of the module A in order to cancel this.

The output power of the module A is 0.3P.
In synchronism with lowering to s, the power control means 39 causes the power converter 1 to start discharging at an output power of 0.7 Ps.
Give instructions to 1b. The power converter 11b causes the module B to discharge at 0.7 Ps according to the instruction. Similar to the case of the module A, the current value is initially made almost constant, but gradually increases as the depth of discharge increases. For reference, FIG. 4 shows a state of current change when each of the modules A and B continues to discharge at the rated output power Ps (prior art), and the rated I
It is shown by a broken line as p.

Although not particularly mentioned so far, during the operation,
The switch 10 is naturally closed. Further, the AC / DC switching command 392 has the content of converting DC to AC.

FIG. 5 shows the power loss of each module and the power loss of the entire power storage / dispersed power supply system 19 when such an operation is performed. The discharge efficiency ηc of the module A is 88%, which is higher than the discharge efficiency (= 70%) at the rated output power. This is because the output after the depth of discharge of 50% is reduced to 0.3 Ps. Similarly for module B, discharge efficiency ηc
Is 88%, which is higher than that during rated operation. The discharge efficiency of the entire system is 88% (power loss 12%). For comparison, FIG. 5 also shows the voltage change and the amount of power loss when one secondary battery module is continuously operated at the rated power Ps (conventional technology). In this case (prior art), the rated discharge efficiency ηc is 70% (power loss 30%). That is, in this embodiment, the efficiency is improved by 18% as compared with the conventional system.

As described above, in this embodiment, by optimizing the power distribution among the modules according to the depth of discharge, that is, the internal resistance characteristic, highly efficient operation becomes possible.

In the present embodiment, the magnitude of the output power of each module was defined in relation to the depth of discharge in the operation plan. However, the present invention is not limited to this, and an operation plan that defines the output power in relation to the internal resistance of the battery may be created. Furthermore, the magnitude of the output power may be defined in relation to the internal resistance and a certain amount that can be detected (or calculated).

Note that obtaining the depth of discharge corresponds to indirectly obtaining the internal resistance.

[Second Embodiment] The second embodiment is characterized in that the peak cut operation of the system power can be performed by predicting the power demand. It is also characterized in that it is possible to cope with abnormal load fluctuations.

Electric power storage distributed power supply system 2 of the second embodiment
An outline of the power supply system including 0 is shown in FIG. The difference between the power storage distributed power supply system 20 and the power storage distributed power supply system 19 of the first embodiment is only in the power control means 30. Therefore, only the power control system 30 will be described here, and description of other parts will be omitted.

Details of the power control system 30 will be described with reference to FIG.

The power control system 30 includes a power demand prediction means 32, a past case data storage means 33, an operation plan creation means 34, a basic data storage means 36, an input means 37, an arithmetic unit 40, an operation plan correction means 38, and power control. It is configured to include means 39 and the like.

The power demand predicting means 32 has a function of predicting daily, daytime, or nighttime power demand of the load 3 at predetermined time intervals (hereinafter referred to as "long-term prediction"). Further, it has a function (hereinafter, referred to as “sequential prediction”) of sequentially predicting the power demand one hour or 30 minutes ahead from the current time. These predictions are performed by inputting a factor (hereinafter referred to as “influence factor”) 321 that affects the power demand to a neural network that has learned the past case data 330 stored in the storage unit 33.
Therefore, it is possible to highly accurately predict demand changes specific to the system to be controlled, such as industrial areas and residential areas. Influencing factor 3
21, for example, weather forecast information such as temperature and humidity,
Weekend holidays and event information. Past case data 3
30 is the content of the influencing factor 321 (33
1) and past demand data 351 configured to include a power demand value for each time and the like are stored in association with each other. The past case data 330 is used to create teacher data necessary for learning the neural network. The details of the neural network will be described later.

The power demand forecasting means 32 is constructed so as to output the result of the long-term forecast to the operation plan creating means 34 as the demand forecasting result 322. On the other hand, the result of sequential prediction is
The sequential prediction result 323 is output to the operation plan correction means 38.

The basic data storage means 36 is the same as in the above embodiment. That is, the basic data storage means 36 stores data such as the open circuit voltage and the internal resistance of the modules A and B.

The input means 37 is for inputting various operational constraints and the like. As a constraint condition, in the present embodiment, for example, for each module A and B,
There is a relationship between the depth of discharge and the upper limit of output power. In addition, the range of the depth of discharge used during normal operation or the range of the depth of discharge used only in an emergency is mentioned (Dxc and Dxd in the example described later correspond to this).

In addition to the above, other constraint conditions in the operation plan preparation include a priority level between the modules A and B in charging / discharging. However, this priority level is fixed and cannot be changed by input from the input means 37. The priority level is provided in advance by the operation plan creation means 34 itself.

The arithmetic unit 40 performs a predetermined arithmetic operation (for example, A / D conversion) on the detection result of the current / voltage detector 9,
The data is output to each operation plan creation means 34.

The operation plan creating means 34 obtains the electric energy and the depth of discharge based on the detection result of the current / voltage detector 9,
This is combined with the current value and the voltage value, and the operation plan correction means 38
It has a function to output to. In addition, modules A and B
It is equipped with a function to create an operation plan. The operation plan includes the power demand forecast result 322, the power operation regulation condition 371 input from the input unit 37, and the basic data storage unit 36.
It is created using various data in the above, measured values of the voltages and currents of the modules A and B, and the like. Further, although not clearly shown in the figure, the operation plan of the power source 1 of the system is input. When the peak cut operation is performed, an operation plan is created after the end of charging and before the start of discharging. The created operation plan is the operation data storage means 3
Stored in 5. In addition to this, the operation data storage unit 35 stores the actual measurement data and the calculation result (charge / discharge capacity, discharge depth, power amount, efficiency, loss, etc.) of each module by the operation plan creation unit 34. It Further, the operation plan correction means 38 includes a voltage, current, electric energy,
A signal 401 indicating the depth of discharge is output.

The operation plan correction means 38 uses the sequential prediction result 3
23, a function for correcting the operation plan is provided. The corrected operation plan is sent to the power control means 39 by a control signal 381.
Send as. The operation plan correction means 38 further changes the output power of each module according to the depth of discharge input from the operation plan creation means 34 (Note: this is defined in the operation plan as in the first embodiment above). It has a function to make corrections. Besides this,
The operation plan correction means 38 also has the same function as the system protection determination means in the first embodiment. That is, the presence / absence of abnormality is determined based on the system power detected by the system monitor 13 and the frequency measurement value 380, and if there is an abnormality, the power control means 39 is instructed to switch to the emergency operation mode. Output.

The power control means 39 is the operation plan correction means 3
Operation Plan Corrected by 8 (Control Signal 381)
The control signals 391 to 394 are output in accordance with
0, power converter 11 and the like.

"Control means" referred to in the claims
In the present embodiment, is constituted by the power control means 39, the operation plan creation means 34, and the like. The operation plan creating means 34 corresponds to the "parameter means" in the claims. However, since the power control system as a whole operates in close cooperation, the correspondence with the claims described here is not strict. As long as the above-mentioned functions are realized in the entire power control system, any specific division (or division) of functions may be made.

Details of the power demand predicting means 32 will be described with reference to FIG. As described above, in this embodiment, the power demand forecasting means 32 is constructed by using the neural network.

The demand forecasting means 32 comprises a target data creating means 3201, a neural network 3205, an input data creating means 3206, and a comparison / correction means 3203.

As is widely known, the neural network 3205 is composed of an input layer, a middle layer, and an output layer including a plurality of neurons. The neurons between the layers are connected to each other. A weighting factor is attached to each of the combinations. The neuron multiplies the input signal by a weighting factor and outputs it to another neuron. Since the weighting factor is different for each connection, the output to the other neurons is different for each connection. The weighting coefficient to be given to each connection is optimized in advance using the teacher data (hereinafter "learning").
Output 2 for a certain input 3207
04 is the predicted value of the target data. The input 3207 for the actual prediction is the input data creating means 32.
06 is created using the influencing factor 321.

The teacher data is the neural network 3
It consists of a combination of input data to 205 and target data corresponding to the input data. The target data creation unit 3201 creates the target data by normalizing the past data 351 stored in the storage unit 33. The input data corresponding to the target data is created by the input data creating means 3206 by normalizing it using the past case data 331 stored in the storage means 33.

Input data included in the teacher data is input to the input layer of the neural network. Accordingly, the data 3204 output from the output layer and the target data are matched (or approximated) with each other as appropriate.
Learning can be performed by adding a correction (the correction operation is shown as an arrow 3208 in the figure) to the weighting coefficient for each connection. The comparison / correction unit 3203 compares the data 3204 with the target data and corrects the weighting coefficient. The neural network 3205 of the present embodiment is preliminarily learned using teacher data composed of past case data 331 (input data) and past data 351 (input data).

The pack propagation method is an example of a specific learning method for the neural network and a specific calculation method for modifying the weighting factor. For details on neural networks and their learning methods, see, for example, "Lear
ning internal representations by error propagatio
n) Parallel Distributed Processing: Explorations in
the Microstructures of Cognition, 1986, Vol.1, Chapte
r41, pp.675-695: MA: MIT Press, pp.318-362.

The operation plan preparing means 34 prepares an operation plan 341 which satisfies all of the above-mentioned various constraint conditions. In this embodiment, a mathematical programming method is used to create the plan. Since the mathematical programming method is already widely known, its explanation is omitted. For example, it is described in "Optimum Cogeneration Plan" Koichi Ito, Ryohei Yokoyama: Sangyo Tosho Co., Ltd. However, the specific method for creating the operation plan is not limited to this.

The operation will be described.

Here, description will be given on the assumption that the constraint conditions which are the premise of the operation plan preparation are set as follows (see FIG. 9).

Module A: The area of Dxc is reserved for emergency charging. Normally, charging / discharging is performed only in a discharge depth region of Dxc or more (this corresponds to the “predetermined range” in the claims). The rated power Ps is the upper limit of the output power up to the depth of discharge of 50%. In the region where the depth of discharge is 50% or more, the upper limit of the output power is 0.5 Ps and the lower limit is 0.1 Ps, and the output power can be freely set within this range.

Module B: The area of Dxd is reserved for emergency discharge. Therefore, normally, charging and discharging are performed only in a region having a smaller depth of discharge (this corresponds to the "predetermined range" in the claims). The rated power Ps is the upper limit value of the output power up to the depth of discharge of 50%. Depth of discharge 50%
In the above range, the upper limit value of the output power is 0.5 Ps.

For normal discharge, the module A is given priority. The module B is preferentially charged. Dxc and Dxd are set to appropriate values in consideration of the variability of system power and the utilization efficiency of equipment, but are preferably about 10 to 40%. For reference, FIG. 10 shows the relationship between the depth of discharge and the rated amount of power that can be charged and discharged. As is clear from FIG. 10, by restricting the depth of discharge, it is possible to secure the required rated power amount. In this embodiment, Dxc = 20 ±
By setting 5% and Dxd = 40 ± 5%, it is possible to secure the rated power amount Wxc that can be charged in an emergency of 23 ± 5% and the rated power amount Wxd that can be discharged of 30 ± 5%.

Under the above constraint conditions, the rated charging / discharging electric energy Wt in normal times can be obtained from the following expression 12.

[0109]

[Formula 12] Wt = (Wa-Wxc) + (Wb-Wxd) Wt: Rated charge / discharge power amount in normal time Wa: Total rated power amount of module A Wxc: Rated power amount capable of charging in an emergency Wb: Module B Of the total rated power Wxd: rated power that can be discharged in an emergency The result of the long-term prediction by the power demand prediction means 32 is shown in FIG.
In the case of (a), the peak of the power demand cannot be met only by the power supply 1 of the system. In addition, there is excess power in the time period when the power demand decreases. Therefore, it is necessary to perform the peak cut operation as shown in FIG. That is, the time ta- when the power demand decreases
During time tb, the surplus electric power is charged to the modules A and B. On the other hand, discharging is performed between time tc and time te when power demand is tight. The charging power amount Wc and the discharging power amount Wd are
Naturally, it must be equal to or lower than Wt in Expression 12.

Therefore, the operation plan preparation means 34 prepares an operation plan for the power distribution between the modules A and B for performing the peak cut operation while satisfying the above-mentioned constraint conditions. Further, the operation plan correction means 38 corrects the operation plan according to the result of the sequential prediction. Here, FIG.
Taking the discharge from time tc to time te in (b) as an example, the operation of correcting the operation plan will be described with reference to FIGS. 12 and 13.

First, the operation plan initially set up will be described.

Module A starts discharging from time td ₁ . From time td1 to time td2, discharging is performed with output power according to demand. At this time, since the discharge depth is still small, the output power from module A is maximum, P
can be increased to s. From time td2 to time td3
During the period, the output power was reduced because of the low demand. Since the demand increases again from time td3, the output power of the module A should also increase accordingly. However, in calculation, the discharge depth of the module A reaches 50% between the time td2 and the time td4. Therefore, after that, the module A discharges with the output power (maximum 0.5 Ps, minimum 0.1 Ps) according to the depth of discharge until time td6.

It is predicted that demand will increase again at time td4. As described above, the depth of discharge of module A has already exceeded 50%.
This alone cannot handle this. Therefore, at the time td4, the module B is started up, and the module B is discharged by the amount that the module A alone lacks.

After that, since it is predicted that the demand will gradually decrease, the output power from the power storage / dispersed power supply system 20 is also reduced accordingly. Here, the constraint condition specifies that the module A is discharged first. Therefore, the module B is given priority to reduce the output power. The output power of the module A is reduced in accordance with the decrease in demand even after the discharge from the module B is completely stopped.
This is the case when there is more power than demand.

In spite of having made such an operation plan, there is a case where a demand different from the long-term prediction result is predicted as a result of the sequential prediction. In this case, the operation plan correction means 38 appropriately corrects the operation plan, and the power control means 3
Issue a command to 9. Here, in FIG. 12, electric power We
Consider, for example, a case where the demand is larger than the long-term forecast by the amount indicated by 1, We2.

The operation plan correction means 38 compares the result of the sequential prediction with the operation plan (or the long-term prediction result which is the basis of the operation plan). Then, it can be seen that an unexpected power demand We ₁ is newly generated at time td ₃ . Therefore, the operation plan correction means 38 uses the module B
The start timing time of is advanced from time td ₄ to td ₃ . Also for the module A, the output power after the discharge depth exceeds 50% is taken into consideration in consideration of the power demand We1.
A little larger than originally planned.

Further, an unexpected power demand We ₂ occurs between time td ₅ and time td ₆ . Therefore, module B
To cope with this, keep the output power of the higher than originally planned.

Next, the operation of responding to an emergency will be described.

In this embodiment, it is also possible to suppress a sudden change in the system frequency due to an abnormal load change such as reverse power flow.

In an emergency (for example, when the frequency fluctuation of the grid detected by the grid monitor 13 exceeds a certain fluctuation range), the power from the power storage / dispersed power supply system 20 is exchanged to stabilize the grid frequency. Turn into

When the system frequency is lowered (that is, when the power supply is insufficient for the demand), the modules A and B are in this order in accordance with the discharge priority condition, or both modules A and B are used as required. Powered by. In the present embodiment, the time zone in which the power storage amount of the system is the smallest (time te-time ta in FIG. 11B).
However, the power amount Wxd is secured in the module B. Therefore, even if an unexpected increase in power demand occurs, this can be dealt with.

On the contrary, when the system frequency rises (that is, when the electric power supply greatly exceeds the demand),
Electric power is charged in the order of the modules B and A, or both of the modules A and B as necessary. Therefore, even in the time zone in which the power storage amount of the system is the largest (time tb-time tc in FIG. 11B), the module A has a sufficient capacity to charge the power amount Wxc. Therefore, it is possible to deal with a situation where the power demand unexpectedly drops.

As described above, in this embodiment, the operation plan is prepared and revised based on the demand forecast,
High-accuracy peak cut power operation that enables load following the actual power demand becomes possible. In addition, it is possible to improve the energy conversion efficiency of the secondary battery equipment while supplying necessary power to the grid.

Furthermore, by always ensuring a chargeable / dischargeable area, it is possible to sufficiently deal with an emergency.

In this embodiment, the output power was adjusted with reference to the depth of discharge of 50%. However, it goes without saying that a larger number of discharge depths serving as the reference may be set and more finely set. Alternatively, the limit of the output power may be set continuously according to the depth of discharge. This makes it possible to operate with less power loss. However, it is preferable to set an appropriate step size in consideration of easiness of control, a calculation method for optimizing and the time required for this, a target of power loss reduction, accuracy of demand prediction, and the like.

In the above description, only the discharging was mainly described, but from the same viewpoint in charging, the charging current may be adjusted according to the depth of discharge. However, since charging is basically performed using surplus power, there are restrictions on the charging time and the like. Therefore, the charging current may be determined by giving priority to these various constraint conditions.

[Embodiment 3] This embodiment is a hybrid system in which fuel cell power generation equipment is connected in parallel with secondary battery equipment such as secondary battery modules 7a and 7b.

Electric power storage distributed power supply system 21 of the present embodiment
A power supply system equipped with is shown in FIG.

Since the secondary battery equipment and the control-related components are made up of the same equipment as in the second embodiment, their explanations are omitted here.

The fuel cell module 8 electrochemically reacts air and fuel gas to obtain DC power.
The fuel cell module 8 is formed by stacking a plurality of unit cells. The fuel cell module 8 is configured to output the generated power to the power distribution system line 4 or the secondary battery modules 7a and 7b. The output destination is changed by the switches 10c, 10d ₁ and 10d ₂ described later.

The secondary battery modules 7a and 7b store the power generated by the fuel cell module 8 and discharge the stored power to the power distribution system line 4. Unlike the above embodiment, the power generated by the power supply 1 is not stored in the secondary battery modules 7a and 7b. For charging, the DC output generated by the fuel cell module 8 is directly (direct / direct
It is efficient because it can be performed (without interchanging). The difference from the above-described embodiment is realized by peripheral circuits (for example, switches 10a to 10d, power converter 11 and the like), and the secondary battery module 7a,
7b itself may be the same as in the above embodiment. However,
The maximum charging current density of the secondary battery modules 7a and 7b is
It is set higher than the current density output by the fuel cell.

The auxiliary equipment 80 is various equipment related to the fuel cell module 8, such as a fuel supply means and a heater.

The current / voltage detector 9c detects the current value and voltage value of the output from the fuel cell module 8. The detection result is output to the power control system 31.

The switch 10c is used for the fuel cell module 8
And for connecting / disconnecting the electric circuit of the power distribution system line 4. The switches 10d ₁ and 10d ₂ are for connecting / disconnecting the secondary battery modules 7a and 7b and the fuel cell module 8 on the DC side. As I said,
The switches 10c, 10d ₁ and 10d ₂ are used to change the output destination (power distribution system line 4, secondary battery modules 7a, 7b) of the electric power generated by the fuel cell module 8.

The DC voltage regulator 16 adjusts the fuel cell power generation voltage.

The above-mentioned units are the same as those in the power control system 31.
It is configured to operate according to a command signal from.

The power control system 31 basically has the same function as that of the second embodiment, controls the fuel cell module 8 and cooperates with the fuel cell 8 and the secondary cell modules 7a, 7b. It has a function to control. Details of the power control system 31 will be described below with reference to FIG. 15.

The basic configuration of the power control system 31 is as follows.
Although it is similar to the power control system of the second embodiment, the functions of the respective functional sections are slightly different because it is necessary to control the fuel cell module 8 as well. Therefore, in the following, differences from the power control system according to the second embodiment will be mainly described.

The basic data stored in the basic data storage means 36 may be the same as in the above embodiment.

From the input means 37, various constraint conditions for protecting the fuel cell module are input in addition to the constraint conditions similar to those in the above embodiment.

The operation plan creation means 34 has a function of determining an operation plan for satisfying the result of the long-term prediction by the power demand prediction means 32. The "operation plan" referred to in the present embodiment includes not only the load distribution between the secondary battery modules 7a and 7b but also the adjustment plan of the output power of the fuel cell module 8 (Note: in this respect, the first , Different from the second embodiment). The operation plan is basically
The peak cut operation is performed using the secondary battery modules 7a and 7b so that the output fluctuation of the fuel cell module 8 is minimized. In this case, it is natural that the plan is created in consideration of the depth of discharge of the secondary battery module 7 at that time (or when the operation plan is executed). The load distribution between the secondary battery modules 7a and 7b is determined according to the second embodiment.
From the same viewpoint as in the preparation of the operation plan in.

In order to create an operation plan, it is necessary to know the electric power that should be output as the entire electric power storage and distributed power supply system. And for that purpose, it is necessary to know the output electric power value which the power supply 1 has planned. Therefore, the operation plan creation means 34 of the present embodiment receives the operation plan of the power source 1 and the like as the base power operation information 310.

The operation plan correcting means 38 is the demand forecasting means 3
The operation plan is appropriately modified according to the result of the sequential prediction by 2. The correction is basically performed by correcting the output power of the secondary battery modules 7a and 7b. This is because if the output power of the fuel cell module 8 is changed frequently, the power generation efficiency and life will be shortened. However, needless to say, the output power of the fuel cell module 8 is corrected when the secondary battery modules 7a and 7b alone cannot handle the problem.

The power control means 39 is the operation plan correction means 3
According to the instruction from 8, various control signals 3 for controlling the fuel cell module 8 and the secondary cell modules 7a, 7b
91 to 395 are output. Fuel cell output adjustment signal 3
Reference numeral 95 is for adjusting the output voltage of the fuel cell module 8, and is output to the DC voltage adjuster 16. The opening / closing operation command 391 is issued to the switches 10a, 10b, 10c,
It is output to 10d1 and 10d2. The AC / DC conversion switching command 392 and the power setting signal 393 are output to the power converters 11a, 11b, 11c. The auxiliary equipment control signal 394 is output to the auxiliary equipment 8a, 8b.

The operation of this embodiment will be described with reference to FIG.

The operation plan preparation means 34 subtracts the electric power Po supplied from the power source 1 from the electric power demand in the load 3 and prepares an operation plan supplied by the electric power storage distributed power supply system 21. Since the electric power Po is generally kept constant, description of the operation of the power supply 1 of the system is omitted.

In normal times, power is supplied from the fuel cell module 8 (or from both the fuel cell module 8 and the secondary cell module 7) to the side of the power distribution system line 4. That is, during the daytime (time tc-time te), the power demand is large and the fuel cell module 8 alone lacks power, so the shortage Wd is discharged from the secondary battery modules 7a and 7b (see FIG. 16 (a)). . So in this case,
The power control means 39 opens the switches 10d ₁ and 10d ₂ . Further, the switches 10a, 10b, 10c are closed. On the other hand, at night (time ta-time tb), the demand decreases and the electric power remains, so the electric power generated by the fuel cell module 8 is stored in the secondary battery module 8 (see FIG. 16A). Therefore, in this case, the power control means 39 closes the switches 10c, 10d ₁ and 10d ₂ . Switch 10
a and 10b are open circuits. The electric power (electric energy Wc) required to perform the peak cut operation in the daytime is supplied by the electric power charged at this time. The secondary battery module 7
The load distribution between a and 7b is performed from the same viewpoint as in the second embodiment.

As described above, in the present embodiment, the power source 1 located on the upper side of the system can continue to operate at a constant output. Moreover, the energy conversion efficiency in the secondary battery modules 7a and 7b can be kept high. Furthermore, fluctuations in the output of the fuel cell module 8 can be reduced (see FIG. 1).
6 (b)). If the secondary battery modules 7a and 7b having a sufficiently large capacity are adopted, it is possible to perform an operation in which the output of the fuel cell module 7 is always kept constant. Furthermore, the greater the chargeable current density of the secondary battery modules 7a and 7b, the greater the flexibility with respect to fluctuations.

Next, how to deal with a sudden change in the system load will be described.

Here, as shown in FIG. 17, the distribution system line 4
Consider a case in which the AC load group 23 is connected to each of the plurality of system feeders F _{1 to} F _n branched off from. Further, the system feeders F _{1 to} F _n are respectively equipped with circuit breakers 5 _{(1) to} 5 _(n) .

[0151] In such a configuration, for example, aberrations in the system feeder F ₃ (e.g., ground faults accident) occurs, said line feeder F ₃ is immediately disconnected from the power distribution system lines 4 by breaker 5 ₍₃₎ . Then, the load 23 provided in the system feeder F ₃ drops off (that is, the power demand sharply decreases), and the frequency of the distribution system line 4 rapidly increases as it is.

However, in this embodiment, the operation plan correction means 3
8 detects an abnormality (in this case, an increase in frequency) based on the signal from the system monitor 13, and notifies the power control unit 39 of that fact. Then, the power control unit 39 opens the switches 10a and 10b to stop the output from the secondary battery module 7 to the distribution system line 4 in order to cope with the abnormal state. At the same time, the switches 10d ₁ and 10
By closing d ₂ , at least part of the electric power output from the fuel cell module 8 is stored in the secondary battery module 7. Thereby, the output of the power storage distributed power supply system 21 can be reduced without reducing the output of the fuel cell module 7. And the rise of the frequency in the distribution system line 4 can be suppressed to the minimum.

A sudden reverse power flow from the system load group 3 can be dealt with in the same manner.

As a result, the fuel cell module 7 can continue to operate in a state where the facility operating rate is high. Further, since the upper power supply 1 is also less affected by load fluctuations in normal times and in an emergency, it is possible to operate with a high output and a constant output. Even if a solar cell power generation facility is adopted instead of the fuel cell power generation facility, the same effect can be obtained.

Next, as another example, a case of an emergency when the power storage distributed power supply system 21 is provided between the loads of the system feeder as shown in FIG. 20 will be described.

The system feeder F _x is connected via the circuit breaker 5 _x ,
It is connected to the distribution system line 4. A large number of AC power load groups 23 and switches 17 are connected to the system feeder F _x . Further, the power storage and distributed power supply system 2 is connected to each part of the system feeder F _x via the circuit breaker 50.
1 is connected.

When an accident occurs in any part of the system feeder F _x, the power storage distributed power supply system 21 provided in the section where the accident occurred must be disconnected from the system feeder F _x by opening the circuit breaker 5. I have to. Then, in that case, the fuel cell module 8 of the power storage distributed power supply system 21 may be forced to operate in an extremely low load. The output of the fuel cell cannot be instantaneously reduced, and sudden changes in the load lead to a marked reduction in the life of the fuel cell equipment. However, in this embodiment, the output of the fuel cell is instantaneously changed to the secondary battery module 7
Since it can be devoted to the charging of a and b, it is possible to deal with such a situation without sharply reducing the output of the fuel cell module 8.

Furthermore, when an accident occurs between the circuit breaker 5 _x and the switch 17b in FIG. 18, the load group 2 is transferred from the power storage distributed power supply system 21 arranged on the downstream side.
Electric power can be supplied to 3a and 3b. Therefore, the power failure section can be made as small as possible.

[Embodiment 4] This embodiment is characterized in that both the AC power and the DC power are supplied from the power storage distributed power supply system 21 according to the present invention.

FIG. 19 shows a power supply system equipped with the power storage distributed power supply system of this embodiment. The electric power storage / distributed power supply system 21 itself basically has the same configuration as that of the second or third embodiment, but in the present embodiment, it further includes the DC power output means 45.

The DC power output means 45 supplies DC power to the DC power consumer 47 through the DC power system line 46. The DC power output means 45 is composed of a switch and an output voltage regulator which are circuit-connected to each battery module (secondary battery, fuel cell). The operation of the DC power output means 45 is controlled by the power control system 30 or 31.

The DC power system line 46 is connected to the DC power consumer 4
It is a cable for guiding power to 7. In this embodiment,
It is buried underground to prevent blackouts caused by lightning strikes.

The DC power consumer 47 may be, for example, a charging stand for electric vehicles or a computer user.

In this embodiment, high-quality and highly reliable DC power can be efficiently supplied to DC power consumers.

[0165]

As described above, according to the present invention, the energy conversion efficiency of the secondary battery can be improved. In addition, it is possible to stabilize the supplied power even when the load changes suddenly in an emergency.

Furthermore, the stability of the upper system power supply can be ensured. This leads to an improvement in the operating rate of the upper system power supply.

[Brief description of drawings]

FIG. 1 is a block diagram showing a power storage distributed power supply system 19 and a power supply system including the same according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a functional configuration of a power control system 29.

FIG. 3 is a graph showing characteristic data of a sodium-sulfur battery stored as basic data.

FIG. 4 is a graph showing an example of power distribution operation for each secondary battery module.

FIG. 5 is a graph showing a power loss ratio in this embodiment.

FIG. 6 is a block diagram showing an electric power storage and distributed power supply system 20 and a power supply system including the same according to a second embodiment of the present invention.

FIG. 7 is a block diagram showing a functional configuration of a power control system 30.

FIG. 8 is a block diagram showing an outline of a neural network that constitutes demand prediction means.

FIG. 9 is a diagram showing an example of constraint conditions.

FIG. 10 is a graph showing the relationship between the depth of discharge and the rated power amount.

FIG. 11 is a graph showing an example of (a) a demand forecast result and (b) a peak cut operation performed for the demand forecast.

FIG. 12 is a diagram showing an example of a power distribution operation plan and its modification.

FIG. 13 is a diagram showing load distribution of each module corresponding to the operation plan and correction of FIG. 12;

FIG. 14 is a block diagram showing a power storage and distributed power supply system 21 and a power supply system including the same according to a third embodiment of the present invention.

FIG. 15 is a block diagram showing a functional configuration of a power control system 31.

FIG. 16 is a graph showing an operation example of the third embodiment.

FIG. 17 is a power storage distributed power supply system 2 according to a third embodiment.
FIG. 3 is a block diagram showing an example in which 1 is connected to a system bus having a plurality of system feeders.

FIG. 18 is a power storage distributed power supply system 2 according to a third embodiment.
1 is an example in which 1 is provided between the loads of the system feeder and the system is interconnected.

FIG. 19 is a block diagram of a power supply system for supplying DC power from the power storage distributed power supply system according to the present invention.

FIG. 20 is a configuration example of a conventional power storage system.

FIG. 21 is a graph showing power loss in the related art.

[Explanation of symbols]

1 ... Power source, 2 ... Distribution substation, 3 ... System load group, 4 ... Distribution system, 5 ... Circuit breaker, 6 ... Transformer, 7 ... Secondary battery module, 8 ... Fuel cell Module, 10 ... Switch, 11 ... Power converter,
12 ... Electric power control unit, 14 ... Operation plan creation support means, 16 ... DC voltage regulator, 19 ... Electric power storage distributed power supply system, 20 ... Electric power storage distributed power supply system, 21 ... Electric power storage distributed power supply system , 29 ... Power control system, 30 ... Power control system, 31
...... Power control system, 32 ...... Power demand prediction means, 33 ...... Storage means, 34 ...... Battery operation plan creation means, 36 ...... Basic data storage means, 37 ...... Constraint condition input means, 38 ...... Operation plan Correcting means 39 ...
Power control means, 45 ... DC power output means, 46 ...
… DC power system line, 47 …… DC power consumers

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shigeoki Nishimura 7-1, 1-1 Omika-cho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi Research Laboratory (72) Inventor ▲ Yoshi ▼ Masanori Kawa Omika, Hitachi-shi, Ibaraki 7-1-1, Machi, Hitachi, Ltd., Hitachi Research Laboratory (72) Inventor Minoru Kanai 7-1, 1-1, Omika-cho, Hitachi-shi, Ibaraki Hitachi, Ltd., Hitachi, Ltd. (72) Akiyasu Okuno 2-30, Kanda-Jinbocho, Chiyoda-ku, Tokyo Tokyo Electric Power Company, Inc. R & D Laboratory (72) Inventor Yutaka Horikawa 2-3-2, Kanda-Jimbocho, Chiyoda-ku, Tokyo Tokyo Electric Power Company, Inc.

Claims (8)

[Claims] 1. A secondary battery module configured to include one or more secondary batteries, and a value of a parameter (hereinafter referred to as "parameter value") having a correlation with the internal resistance of the secondary battery. An electric power storage system comprising: parameter means; and control means for adjusting discharge power from the secondary battery module according to a parameter value obtained by the parameter means. 2. The control means comprises a reference value of the parameter determined on the basis of the relationship with the internal resistance, and the adjustment is a magnitude relationship between the reference value and the parameter value obtained by the parameter means. The power storage system according to claim 1, wherein the power storage system is performed based on 3. The power storage system according to claim 2, wherein the adjustment is to reduce the discharge power in a region where the internal resistance is large. 4. The power storage system according to claim 1, wherein the parameter is a depth of discharge of the secondary battery. 5. The control means causes the secondary battery module to be discharged and / or charged within the range where the depth of discharge is predetermined. Power storage system. 6. A plurality of the secondary battery modules, which are arranged in parallel with each other and are configured to be capable of controlling their charging and discharging independently of each other, wherein the control means has a predetermined value for each of charging and discharging. The power storage system according to claim 3, further comprising a priority level between the secondary battery modules, and performing the charging and discharging according to the priority level. 7. The control means permits discharge from a secondary battery module with a low priority level when the power is insufficient only with the power discharged from the secondary battery module with a high priority level. The power storage system according to claim 6, wherein: 8. A method of operating a power storage system using a secondary battery, wherein the internal resistance of the secondary battery is directly / or indirectly determined, and the output of the secondary battery is determined according to the magnitude of the internal resistance. Adjusting at least one of electric power and input electric power, The operating method of the electric power storage system characterized by the above-mentioned.