JP3599387B2 - Power storage system - Google Patents

Power storage system Download PDF

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Publication number
JP3599387B2
JP3599387B2 JP27223094A JP27223094A JP3599387B2 JP 3599387 B2 JP3599387 B2 JP 3599387B2 JP 27223094 A JP27223094 A JP 27223094A JP 27223094 A JP27223094 A JP 27223094A JP 3599387 B2 JP3599387 B2 JP 3599387B2
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Japan
Prior art keywords
power
discharge
module
output
battery
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JP27223094A
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JPH08140285A (en
Inventor
正則 ▲吉▼川
康司 佐藤
実 叶井
正明 向出
豊 堀川
晃康 奥野
成興 西村
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東京電力株式会社
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Description

[0001]
[Industrial applications]
The present invention relates to a power storage system using a secondary battery.
[0002]
[Prior art]
The power storage system is used for load leveling and peak cutting of system power, and for stabilizing system frequency and system voltage.
[0003]
In recent years, the development of power storage systems using secondary battery modules has been promoted. An outline of a power storage system using a secondary battery and a usage form thereof will be described with reference to FIG.
[0004]
The power generated by a power source (for example, a nuclear power plant or a thermal power plant) 1 of a system serving as a base of the system power is subjected to voltage transformation adjustment in a distribution substation 2 and supplied to a customer of a system load group 3. The power storage distributed power supply system 20 is connected to the distribution system 4 via the circuit breaker 5 and the AC voltage transformer 6.
[0005]
The power storage / distributed power supply system 20 includes a battery module 7 configured by connecting a plurality of secondary batteries in series / parallel, a power control unit 12, and a power conversion unit 11 for performing alternating / direct reversible conversion of power. It is configured. When the power of the power 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. Conversely, when the system power becomes excessive at night or the like, the AC power transmitted from the power distribution system 4 is converted into DC power by the power conversion unit 11, and the battery module 7 is charged.
[0006]
A hybrid power storage system that stabilizes system power in combination with a fuel cell system has also been proposed. For example, JP-A-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 supplies power to a load while floating charging the secondary battery in a charged state, except when compensating for insufficient output of the fuel cell.
[0007]
Secondary batteries used in such power storage systems are required to have high energy density and low charge / discharge loss. Attention has been paid to a sodium-sulfur secondary battery that satisfies such demands, and its development is currently being vigorously continued.
[0008]
It is known that the sodium-sulfur battery has an internal resistance R at the time of discharge increasing in a region where the depth of discharge is high and has a maximum value (see FIG. 3). For such characteristics, see, for example, Electrochem Soc. , Vol. 136, No. 7, P1962, July 1989.
[0009]
In the figure, "depth of discharge" means the total amount of power (discharge capacity) that can be discharged from a battery when discharging is started from a fully charged state and the amount of power already discharged at that time. Ratio. Alternatively, it is the ratio of the time required for the battery voltage to drop to a certain voltage at which the discharge is started from the fully charged state to the certain voltage, and the time that has already passed by that time.
[0010]
[Problems to be solved by the invention]
Assuming that the battery voltage is E, the battery current is I, and the internal resistance is R, the charge / discharge power amount W and the energy conversion efficiency η are represented by the following formulas 1, 2, and 3.
[0011]
(Equation 1)
Charge power amount Wc = ∫I · E dt + ∫I2・ R dt
[0012]
(Equation 2)
Discharge power amount Wd = ∫I · E dt-∫I2・ R dt
[0013]
(Equation 3)
Energy conversion efficiency η = discharge power Wd / charge power Wc
As can be seen from Equation 3, when the charging power amount Wc is considered to be constant, the energy conversion efficiency changes according to the output of the discharge power. Here, considering the case where the charging power amount Wc = the rated power amount Ws (see Expression 4), the energy conversion efficiency ηs is expressed by Expression 5 below. Further, the power loss amount Wp1 is expressed by the following equation (6).
[0014]
(Equation 4)
Rated power amount Ws = ∫I · Eocv dt
Eocv: Open circuit voltage
[0015]
(Equation 5)
Energy conversion efficiency ηs based on rated power = discharge power Wd / rated power Ws
[0016]
(Equation 6)
Power loss Wp1 = Rated power Ws-Discharge power Wd
The power loss amount Wp1 (see Equation 6) corresponds to the second term on the right side of Equation 2. The smaller the internal resistance R, the higher the energy conversion efficiency ηs based on the rated power. In other words, the amount of energy loss increases in a discharge in a 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, it is preferable for the sodium-sulfur battery to perform charging and discharging only in a low-resistance region having a depth of discharge of about 50% or less (see FIG. 3).
[0017]
In addition, a battery generally has a low electromotive force in a region where the depth of discharge is high. In order to constantly supply constant power to the outside (constant power operation), the output current must be increased in the region where the discharge depth is high. Therefore, such constant power operation would further increase the amount of energy loss (see FIG. 21).
[0018]
Further, there is a problem that the larger the size of the battery module, the greater the amount of energy loss due to internal resistance.
[0019]
However, in the conventional system, output control is not performed in consideration of such fluctuations of the internal resistance and the electromotive force according to the charge / discharge depth, resulting in a decrease in energy conversion efficiency.
[0020]
As another problem, the conventional system has not taken sufficient care in response to an emergency. For example, if the load fluctuates suddenly due to an accident or the like, the frequency of the AC power supplied to the system will suddenly change. In such a case, the system frequency can be stabilized by adjusting the active power charged and discharged by the secondary battery. However, in the conventional system, the charge / discharge capacity of the secondary battery is not always limited. When such a situation occurs while approaching the end-of-charge / discharge state, it cannot be dealt with.
[0021]
This problem was the same in the conventional hybrid system. Changing the operating state of the fuel cell system to cope with a sudden change in load causes a significant reduction 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 is abnormally overheated, which causes deterioration of the reforming catalyst and damage to the reformer.
[0022]
As a method for dealing with a situation where the load is small, for example, Japanese Patent Application Laid-Open No. 63-276877 discloses a technique for controlling the output of a fuel cell in accordance with the charge amount of a secondary battery.
[0023]
However, when the battery is near the end of charging at the time of light load such as at night, the system may be disconnected from the system due to a system accident such as a ground fault. In such a case, charging by the secondary battery becomes impossible, so that the output of the fuel cell must be temporarily stopped. Unlike a secondary battery or the like, once the fuel cell is stopped, a startup time is required to increase the output again. In addition, there is a problem that the operating rate of the fuel cell device is reduced.
[0024]
In a conventional hybrid system, charging and discharging of a secondary battery cannot be performed individually and independently for each battery module. Therefore, it was impossible to always secure a chargeable / dischargeable area.
[0025]
An object of the present invention is to provide a power storage distributed power supply system that can sufficiently cope with both normal operation and emergency.
[0026]
SUMMARY OF THE INVENTION An object of the present invention is to provide a power storage / distributed power supply system capable of increasing the energy conversion efficiency as much as possible.
[0027]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION The present invention has been made to achieve the above-described object, and increases the output current (output power) in a region where the internal resistance is low, and decreases the output current (output power) in a region where the internal resistance is high. This is to increase the energy conversion efficiency η (discharge energy / charge energy) of the module. The decrease in output power is compensated for by appropriately combining a plurality of battery modules.
[0028]
Hereinafter, the configuration of the present invention will be described more specifically.
[0029]
According to a first aspect of the present invention, there is provided a secondary battery module including one or more secondary batteries, and a parameter value (hereinafter, referred to as a “parameter value”) having a correlation with an internal resistance of the secondary battery. ") And control means for adjusting the discharge power from the secondary battery module according to the parameter value obtained by the parameter means. You.
[0030]
The control unit includes a reference value of the parameter determined based on a relationship with the internal resistance, and the adjustment is performed based on a magnitude relationship between the reference value and a parameter value obtained by the parameter unit. Preferably, it is
[0031]
Preferably, the adjustment is to reduce the discharge power in a region where the internal resistance is large.
[0032]
The parameter is preferably a depth of discharge of the secondary battery.
[0033]
The control means preferably causes the secondary battery module to discharge and / or charge within a range where the depth of discharge is within a predetermined range.
[0034]
Placed in parallel with each other, independent of charge and dischargeTargetA plurality of the secondary battery modules configured so as to be controllable, and the control unit controls a priority between the secondary battery modules predetermined for charging and discharging respectively.RankingWith the priorityRankingIt is preferable that the above charging and discharging be performed in accordance with the following.
[0035]
The above control means has priorityRankingIf the power discharged from the secondary battery module with highRankingIt is preferable that discharge from a secondary battery module having a low temperature is permitted.
[0036]
According to a second aspect of the present invention, in the method for operating a power storage system using a secondary battery, the internal resistance of the secondary battery is directly or indirectly determined, and the above-described method is performed according to the magnitude of the internal resistance. There is provided a method of operating a power storage system, wherein at least one of output power and input power of a secondary battery is adjusted.
[0037]
[Action]
The control means has priorityRankingCharge and discharge are performed on any of the secondary battery modules determined in accordance with the following. Also priorityRankingIf the power discharged from the secondary battery module with highRankingDischarge from the secondary battery module having a low power. In this case, the control means adjusts the output (discharge power) from the secondary battery module based on the magnitude relationship between the reference value and the value of the parameter (for example, the depth of discharge) obtained by the parameter means. For example, the discharge power is reduced in a region where the internal resistance of the secondary battery is large. Thereby, power loss can be suppressed.
[0038]
Usually, the control means causes the secondary battery module to discharge and / or charge only when the depth of discharge is within a predetermined range. As a result, usually, a certain constant capacity for charging and discharging is always secured, and it is possible to respond to an emergency.
[0039]
【Example】
Embodiments of the present invention will be described with reference to the drawings.
[0040]
[Example 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.
[0041]
The power generated by a power source (for example, a nuclear power plant or a thermal power plant) 1 serving as a base of the grid power is transformed and regulated by a distribution substation 2 and is supplied to consumers of a grid load group 3. The power storage / distributed power supply system 19 of the present embodiment is connected to the distribution system line 4 via the circuit breaker 5 and the AC voltage transformer 6.
[0042]
The power storage distributed power supply system 19 includes secondary battery modules 7a and 7b, battery auxiliary equipment 70, current / voltage detectors 9a and 9b, switches 10a and 10b, power converters 11a and 11b, And a control system 29.
[0043]
Hereinafter, the secondary battery module 7a and the secondary battery module 7b are collectively simply referred to as “secondary battery module 7”. The same applies to the current / voltage detector 9 and the like. The secondary battery module 7a and the secondary battery module 7b may be simply referred to as "module A" and "module B", respectively.
[0044]
The secondary battery module 7 is for storing electric power, and in this embodiment, is configured by connecting sodium-sulfur secondary batteries in series and parallel. The type of secondary battery used and the number of modules 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 to be used. The charging and discharging of the secondary battery modules 7a and 7b can be performed independently of each other. Therefore, for example, it is also possible to charge only the secondary battery module 7a.
[0045]
The battery auxiliary equipment 70 is for maintaining the operating temperature of the battery, such as a heat insulating container and a heater that house the secondary battery module 7. In this embodiment, the battery auxiliary equipment 70 is shared by the secondary battery module 7a and the secondary battery module 7b, but may be independently provided depending on the scale of the battery module.
[0046]
The power converter 11 is for adjusting charging / discharging power of the secondary battery module 7 and performing AC / DC conversion. The power is adjusted by changing the current value. Therefore, the reduction of the output power described later will directly lead to a decrease in the current value. When charging the secondary battery module 7, the AC power supplied from the power distribution system line 4 is converted to DC power, and conversely, when discharging, the DC power released from the secondary battery module 7 is converted to AC power. Convert to electric power. These operations are controlled according to an AC / DC switching command 392 and a 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.
[0047]
The current / voltage detector 9 is for detecting a current value and a voltage value when charging and discharging the secondary battery module 7. The current / voltage detector 9 is connected between the secondary battery module 7 and the power converter 11. The current / voltage detector 9 outputs the measurement result to the power control system 29 as a detection signal 400. These data are used for calculation of the amount of power and the like in the power control system 29 (in particular, the operation plan creation support means 14 described later).
[0048]
The switch 10 is for opening and closing an electric circuit between the two-battery module 7 and the power distribution system line 4. The switch 10 operates according to a circuit switch command signal 391 input from the power control system 29. The switch 10a and the switch 10b are configured to be independently controllable from each other.
[0049]
The power control system 29 is for monitoring and controlling the entire power storage 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 the present embodiment, the power control system 29 is configured by hardware such as a microprocessor and a memory, and software (programs and data) stored in the memory. Hereinafter, the power control system 29 will be described in detail with reference to FIG.
[0050]
The power control system 29 functionally includes a basic data storage unit 36, an input unit 37, an operation plan creation support unit 14, an operation data storage unit 35, an operation plan storage unit 15, a system protection determination unit 12, a power control unit 39. And so on.
[0051]
The basic data storage means 36 stores basic data indicating the relationship between battery characteristics (for example, internal resistance, open circuit voltage, current-voltage) of the secondary battery module 7 and the depth of discharge. However, in order to achieve the object of the present embodiment (reduction of power loss due to output regulation), at least two of the basic relationship between the depth of discharge and the internal resistance and the relationship between the depth of discharge and the circuit voltage are the basics. It only has to be included in the data. The characteristics of the sodium-sulfur battery including the basic data are shown in FIG.
[0052]
The input means 37 is used by a system administrator to input an instruction to the system when creating an operation plan. The “operation plan” here refers to the distribution of power load between the secondary battery module 7a and the secondary battery module 7b, the charge / discharge cut voltage, and the like. In this embodiment, the input means 37 includes a display device, a keyboard, a mouse, and the like. On the display device, various simulation results described later are displayed. Therefore, the system administrator is configured to make these inputs while looking at the display.
[0053]
The operation plan creation support means 14 has a function of calculating the depth of discharge and the amount of discharge power of the secondary battery module 7, the energy conversion efficiency, and the like. In addition, a function for performing various simulations is provided to assist the system administrator in creating an operation plan. Hereinafter, each function will be described in detail.
[0054]
The discharge depth and the discharge power amount are obtained by substituting the actually measured data (the detection signal 400 of the current / voltage detector 9) into the following Expressions 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 history of use of the secondary battery module (for example, the number of cycles, the accumulated amount of electricity, etc.).
[0055]
(Equation 7)
Discharge capacity C (Ah) = {i (t) dt
[0056]
(Equation 8)
Discharge depth D (%) = C / C0
[0057]
(Equation 9)
Discharge power Wd (Wh) = i (t) · E (t) dt− −i2(T) · R (t) dt
C0  : Rated discharge capacity (Ah)
i (t): current value
E (t): voltage
R (t): internal resistance
The energy conversion efficiency ηc and the loss (1−ηc) are calculated based on the measured electric energy after the end of the operation. The calculation result is displayed on the operation control screen of the input unit 37.
[0058]
Simulations such as voltage characteristics and operation efficiency are performed using the constraint conditions, basic data (see FIG. 3) input from the input unit 37, and equations 4 to 11.
[0059]
(Equation 10)
P (D) = I (D) · Eocv (D) −I2(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 depth of discharge D
R (D): Internal resistance at discharge depth D
E (D): battery voltage at depth of discharge D
The operation plan (plan of load distribution between the modules A and B) is configured such that the system administrator creates the operation plan according to his / her own judgment while watching the results of these simulations. For example, by obtaining the discharge depth or the like of the module A at that time (or after a certain amount of power discharge) by the simulation, the output power change timing of the modules A and B (note: the module A will be described later). The discharge depth of 50% corresponds to this) can be included in the operation plan as the actual operation switching “time”. The operation plan created in this way is stored in the operation plan storage means 15 (signal 141). 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 the present embodiment. Therefore, the operation plan will be described later in detail together with the operation description.
[0061]
In this embodiment, the operation plan creation support means 14 corresponds to "parameter means" in the claims. The “control means” is realized by the entire power control system 29 (among them, particularly, the power control means 39).
[0062]
The system protection judging means 12 is for monitoring the presence or absence of an abnormality in the power supply system (FIG. 1). The presence or absence of an abnormality is determined by comparing the signal 142 input from the operation plan creation support means 14 with the detection result (signal 380) of the system monitoring unit 13. Then, the presence / absence of the abnormality and, if there is an abnormality, the content of the abnormality are output to the power control means 39 as the determination signal 121. The system monitor 13 detects a current and a voltage in the power distribution system line 4. The signal 142 indicates a voltage, a current, a power amount, a depth of discharge, and the like.
[0063]
The power control means 39 controls the battery auxiliary equipment 70, the switch 10, and the power converter 11. The power control unit 39 outputs a switching operation command 391 to the switch 10. Similarly, an AC / DC switching command 392 and a power setting signal 393 are output to the power converter 11, and an auxiliary equipment control signal 394 is output to the battery auxiliary equipment 70. The switch 10 and the like are configured to operate according to these control signals 391 to 394.
[0064]
Normally, the power control unit 39 outputs control signals 391 to 394 according to the operation plan stored in the operation plan storage unit 15. However, when an abnormality is notified by the determination signal 121, a special control is performed in response to the notification. For example, when the fluctuation range of the power or frequency in the distribution system line 4 is equal to or larger 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 predetermined depth of discharge, a similar operation is performed to prevent overcharging and discharging. It should be noted that the information defining the content of the special control at the time of such an abnormality is provided in advance by the power control means 39 itself.
[0065]
Next, an example of an operation plan and a criterion for determining the operation plan in the power storage distributed power supply system 19 of the present embodiment will be described with reference to FIG. In addition, the power demand PL of the system load group 3 is satisfied by both the power supplied by the power storage distributed power 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 thus the description is omitted.
[0066]
Here, a case where constant power (here, Ps (W)) is always output will be described as an example. Further, the description will be made assuming that the specifications of the modules A and B are as follows.
[0067]
The module A is operated at the rated power Ps (W) until the depth of discharge reaches 50% (this corresponds to the "reference value" of the parameter in the claims). Then, at the subsequent depth of discharge, the operation is performed with the output power of 0.3 Ps (30% of the rated power). This is because, in a region where the depth of discharge is high (here, 50% or more), the internal resistance increases (see FIG. 3), and thus the power loss is reduced by lowering the output power. As described above, the output power is adjusted by changing the current value.
[0068]
On the other hand, the module B does not output power while the module A is operated at the rated power Ps (that is, when the discharge depth of the module A is 50% or less). When the output power of the module A is 0.3 Ps (that is, when the depth of discharge exceeds 50%), the module B operates at an output power of 0.7 Ps (70% of the rated power). . Regarding the module B, the output power is always set to 0.7 Ps regardless of the discharge depth of the module B itself.
[0069]
By performing such load distribution, even when the output power of the module A is set to 0.3 Ps, the power storage / distributed power system 19 as a whole can continuously output constant power (= rated power Ps). it can.
[0070]
The output power of each of the modules A and B described above (module A: Ps, 0.3 Ps, module B: 0.7 Ps) is the maximum value of the output power in the discharge depth region. When the power demand is small and the output power to be output as the power storage / distributed power supply system 19 is smaller than Ps, it goes without saying that the output power of the modules A and B is appropriately reduced.
[0071]
The reduction of the output power is performed preferentially for the module B. The module A is always preferentially discharged within a range not exceeding the maximum value (Ps, 0.3 Ps) of the output power at each discharge depth. For example, consider a case where the output power required for the entire power storage and distribution power supply system 19 is 0.9 Ps in a region where the discharge depth of the module A is 80%. In this case, the output power of module A is kept at 0.3 Ps, and only the output power of module B is reduced to 0.6 Ps.
[0072]
Next, the operation under the operation plan will be described with reference to FIGS.
[0073]
The output power of the modules A and B is controlled by the power control means 39 operating the power converter 11 and the like according to the operation plan.
[0074]
The power control unit 39 outputs a power setting signal 393 having a content of output power Ps to the power converter 11a. On the other hand, a power setting signal 393 whose content is to set the output power to 0 is sent to the power converter 11b. The current of the module A is initially substantially constant (see FIG. 4). This is because there is no decrease in voltage and no increase in internal resistance in a region where the depth of discharge is shallow.
[0075]
At the time when the depth of discharge exceeds 50% in the operation plan, the power control unit 39 instructs the power converter 11a to reduce the output power from Ps to 0.3Ps. The power converter 11a temporarily reduces the current of the module A correspondingly. However, in the depth of discharge region thereafter, a decrease in voltage and an increase in internal resistance occur. Therefore, the power converter 11a gradually increases the current value of the module A in order to offset the decrease.
[0076]
Further, in synchronization with the reduction of the output power of the module A to 0.3 Ps, the power control unit 39 instructs the power converter 11b to start discharging at the output power of 0.7 Ps. The power converter 11b causes the module B to discharge at 0.7 Ps according to the instruction. As in the case of module A, the current value is initially substantially constant, but gradually increases as the depth of discharge increases. For reference, FIG. 4 shows the state of a current change when each of the modules A and B independently discharges at the rated output power Ps (prior art) by a broken line as the rated Ip.
[0077]
Although not specifically described so far, the switch 10 is naturally closed during the operation. Further, the AC / DC switching command 392 has a content for converting DC to AC.
[0078]
FIG. 5 shows the power loss of each module and the power loss of the entire power storage / distribution 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 discharge depth of 50% is reduced to 0.3 Ps. Similarly, regarding the module B, the discharge efficiency ηc is 88%, which is higher than that during the rated operation. The discharge efficiency of the entire system is 88% (power loss 12%). For comparison, FIG. 5 also shows a voltage change and a power loss amount when one secondary battery module is continuously operated at the rated power Ps (prior art). In this case (prior art), the rated discharge efficiency ηc is 70% (power loss 30%). That is, in the present embodiment, the efficiency is improved by 18% as compared with the conventional system.
[0079]
As described above, in this embodiment, a highly efficient operation can be performed by optimizing the power distribution among the modules according to the depth of discharge, that is, the internal resistance characteristics.
[0080]
In the present embodiment, the magnitude of the output power of each module is 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 may be created in relation to the internal resistance of the battery. Furthermore, the magnitude of the output power may be defined in a relationship with the internal resistance and a relationship with some other amount that can be detected (or calculated).
[0081]
Note that obtaining the discharge depth corresponds to indirectly obtaining the internal resistance.
[0082]
[Example 2]
The second embodiment is characterized in that a peak cut operation of system power is enabled by predicting power demand. Further, the present invention is characterized in that it is possible to cope with abnormal load fluctuation.
[0083]
FIG. 6 shows an outline of a power supply system including the power storage distributed power supply system 20 of the second embodiment. The difference between the power storage distributed power system 20 and the power storage distributed power system 19 of the first embodiment is only the power control means 30. Therefore, only the power control system 30 will be described here, and description of the other parts will be omitted.
[0084]
The details of the power control system 30 will be described with reference to FIG.
[0085]
The power control system 30 includes a power demand prediction unit 32, a past case data storage unit 33, an operation plan creation unit 34, a basic data storage unit 36, an input unit 37, a calculator 40, an operation plan correction unit 38, a power control unit 39, and the like. It is comprised including.
[0086]
The power demand prediction means 32 has a function of predicting the power demand of the load 3 during the day, day, or night at predetermined time intervals (hereinafter, referred to as “long-term prediction”). In addition, a function of sequentially predicting the power demand one hour or 30 minutes ahead from the current time (hereinafter, referred to as “sequential prediction”) is provided. These predictions are performed by inputting factors (hereinafter referred to as “influencing factors”) 321 that affect power demand into a neural network that has learned the past case data 330 stored in the storage unit 33. Therefore, a demand change peculiar to a system to be controlled, such as an industrial area or a residential area, can be predicted with high accuracy. Examples of the influence factors 321 include weather forecast information such as temperature and humidity, weekdays, and event information. The past case data 330 is data in which the contents (331) of the influence factors 321 in the past and past demand data 351 including power demand values at each time are stored in association with each other. The past case data 330 is used for creating teacher data necessary for learning the neural network. Details of the neural network will be described later.
[0087]
The power demand forecasting means 32 is configured to output the result of the long-term forecast to the operation plan creating means 34 as a demand forecast result 322. On the other hand, the result of the sequential prediction is output to the operation plan correction means 38 as the sequential prediction result 323.
[0088]
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 voltages and the internal resistances of the modules A and B.
[0089]
The input means 37 is for inputting various constraints on operation and the like. In the present embodiment, for example, the relation between the depth of discharge and the upper limit of the output power for each of the modules A and B is given as the constraint condition. In addition, a range of a depth of discharge used during normal operation or a range of a depth of discharge used only in an emergency (Dxc and Dxd in examples described later correspond to this).
[0090]
Other constraints on the operation plan creation include a priority between modules A and B in charge / discharge.RankingAnd the like. But this priorityRankingIs fixed and cannot be changed by the input from the input means 37. The priorityRankingAre provided in advance by the operation plan creation means 34 itself.
[0091]
The arithmetic unit 40 performs a predetermined operation (for example, A / D conversion) on the detection result of the current / voltage detector 9 and outputs the result to each operation plan creating unit 34.
[0092]
The operation plan creating means 34 has a function of obtaining the electric energy and the depth of discharge based on the detection result of the current / voltage detector 9 and outputting these to the operation plan correcting means 38 together with the current value and the voltage value. . In addition, a function for creating an operation plan for the modules A and B is provided. The operation plan is created using the power demand prediction result 322, the power operation regulation condition 371 input from the input unit 37, various data in the basic data storage unit 36, the measured values of the voltages and currents of the modules A and B, and the like. Is done. Further, although not clear in the figure, an operation plan of the power supply 1 of the system and the like are also inputted. In the case where the peak cut operation is performed, an operation plan is created from after the end of charging to before the start of discharging. The created operation plan is stored in the operation data storage unit 35. In addition to the above, in the operation data storage means 35, actual measurement data of current and voltage of each module and calculation results (charge / discharge capacity, depth of discharge, electric energy, efficiency, loss, etc.) are stored by the operation plan creation means 34. You. Further, a signal 401 indicating the voltage, current, electric energy, and depth of discharge is output to the operation plan correction means 38.
[0093]
The operation plan correction means 38 has a function of correcting the operation plan using the sequential prediction result 323. The corrected operation plan is sent to the power control unit 39 as a control signal 381. The operation plan correction unit 38 further changes the output power of each module according to the discharge depth input from the operation plan creation unit 34 (note: this is specified in the operation plan as in the first embodiment. The function to make corrections is provided. In addition, the operation plan correction unit 38 has the same function as the system protection determination unit in the first embodiment. That is, the presence or absence of an abnormality is determined based on the system power and the frequency measurement value 380 detected by the system monitor 13, and when there is an abnormality, an instruction to switch to the emergency operation mode or the like is given to the power control unit 39. Output.
[0094]
The power control unit 39 outputs control signals 391 to 394 according to the operation plan (control signal 381) appropriately corrected by the operation plan correction unit 38, and controls the switch 10, the power converter 11, and the like.
[0095]
In the present embodiment, the "control means" in the claims is constituted by the power control means 39, the operation plan creating means 34, and the like. The operation plan creating means 34 corresponds to "parameter means" in the claims. However, since the entire power control system operates in close coordination, the correspondence with the claims described herein is not strict. As long as the above functions are realized as the entire power control system, the specific functions may be assigned (or divided) in any manner.
[0096]
Details of the power demand prediction means 32 will be described with reference to FIG. As described above, in this embodiment, the power demand prediction means 32 is configured using a neural network.
[0097]
The demand forecasting unit 32 includes a target data creating unit 3201, a neural network 3205, an input data creating unit 3206, and a comparing and correcting unit 3203.
[0098]
As is widely known, the neural network 3205 includes an input layer including a plurality of neurons, an intermediate layer, and an output layer. The neurons between the layers are connected to each other. Also, a weighting factor is assigned to each of the combinations. The neuron multiplies the input signal by a weight coefficient and outputs the signal to other neurons. Since the weighting factors are different for each connection, the output to the other neurons will be different for each connection. By using the teacher data and optimizing the weighting factor assigned to each connection in advance (hereinafter referred to as “learning”), an output 204 corresponding to a certain input 3207 becomes a predicted value of target data. The input 3207 for the actual prediction is created by the input data creating means 3206 using the influence factor 321.
[0099]
The teacher data includes a combination of input data to the neural network 3205 and target data corresponding to the input data. The target data is created by the target data creating unit 3201 by normalizing the past data 351 stored in the storage unit 33 and the like. The input data corresponding to the target data is created by the input data creating unit 3206 performing normalization or the like using the past case data 331 stored in the storage unit 33.
[0100]
Input data included in the teacher data is input to the input layer of the neural network. In response to this, the data 3204 output from the output layer and the target data are corrected (or approximated) by appropriately adjusting the weighting coefficient for each connection so that the target data matches (or approximates). (Shown as 3208) can be learned. The comparing and correcting means 3203 compares the data 3204 with the target data and corrects the weight coefficient. In the neural network 3205 of this embodiment, learning is performed in advance using teacher data including past case data 331 (input data) and past data 351 (input data).
[0101]
As an example of a neural network learning method and a specific calculation method of weight coefficient correction, there is a pack propagation method. Details of the neural network and the learning method thereof are described in, for example, "Learning internal representations by error propagation", Parallel Distributed Processing: Explorations in the Microstructure of Cog. 1, Chapter 41, pp., 675-695: MA: MIT Press, pp. 318-362.
[0102]
The operation plan creation unit 34 creates an operation plan 341 that satisfies all of the above-described various constraint conditions. In the present embodiment, mathematical planning is used to create the plan. Mathematical programming is already widely known and will not be described. For example, it is described in "Optimal Cogeneration Planning" by Koichi Ito and Ryohei Yokoyama: Published by Sangyo Tosho Co., Ltd. However, a specific method for creating an operation plan is not limited to this.
[0103]
The operation will be described.
[0104]
Here, the description will be made assuming that the constraint conditions that are the premise of the operation plan creation are set as follows (see FIG. 9).
[0105]
Module A:
The area of Dxc is secured for emergency charging. Normally, charging / discharging is performed only in a discharge depth region equal to or greater than Dxc (this corresponds to a “predetermined range” in the claims). Up to the discharge depth of 50%, the rated power Ps is set as the upper limit of the output power. In the region where the discharge depth is 50% or more, the upper limit of the output power is set to 0.5 Ps and the lower limit is set to 0.1 Ps, and the output power can be set freely within this range.
[0106]
Module B:
The area of Dxd is reserved for emergency discharge. Therefore, usually, charging and discharging are performed only in a region having a smaller discharge depth (this corresponds to a "predetermined range" in the claims). Up to the discharge depth of 50%, the rated power Ps is set to the upper limit of the output power. In the region where the discharge depth is 50% or more, the upper limit value of the output power is set to 0.5 Ps.
[0107]
The normal discharge is performed with priority given to the module A. Charging is performed with priority given to the module B. Dxc and Dxd are set to appropriate values in consideration of system power variability, facility utilization efficiency, and the like, but are preferably about 10 to 40%. For reference, FIG. 10 shows the relationship between the depth of discharge and the rated power that can be charged and discharged. As is clear from FIG. 10, the required rated power amount can be secured by restricting the depth of discharge. In this embodiment, by setting Dxc = 20 ± 5% and Dxd = 40 ± 5%, the rated power amount Wxc that can be charged in an emergency is 23 ± 5% and the rated power amount Wxd that can be discharged is 30 ± 5%. Can be secured.
[0108]
Under the above-described constraints, the rated charge / discharge power amount Wt in normal times can be obtained from the following equation (12).
[0109]
(Equation 12)
Wt = (Wa-Wxc) + (Wb-Wxd)
Wt: Rated charge / discharge power during normal times
Wa: Total rated power of module A
Wxc: Rated power that can be charged in an emergency
Wb: Total rated power of module B
Wxd: Rated power that can be discharged in an emergency
When the result of the long-term prediction by the power demand prediction means 32 is as shown in FIG. 11A, the power demand 1 alone cannot cope with the peak of the power demand. Further, in a time zone in which the power demand decreases, power is left over. Therefore, it is necessary to perform a peak cut operation as shown in FIG. That is, during the time ta to the time tb when the power demand decreases, the remaining power is charged to the modules A and B. On the other hand, discharge is performed between time tc and time te when power demand is tight. Of course, the charging power amount Wc and the discharging power amount Wd must be equal to or smaller than Wt in Expression 12.
[0110]
Therefore, the operation plan creation unit 34 creates an operation plan for power distribution between the modules A and B for performing the peak cut operation while satisfying the above-described constraint conditions. Further, the operation plan correction means 38 corrects the operation plan according to the result of the sequential prediction. Here, taking the discharge from time tc to time te in FIG. 11B as an example, the operation of correcting the operation plan will be described with reference to FIGS.
[0111]
First, an operation plan that has been initially set will be described.
[0112]
Module A is at time td1To start discharging. From time td1 to time td2, discharge is performed with output power that matches demand. At this time, since the depth of discharge is still small, the output power from the module A can be increased up to Ps. The reason why the output power is reduced in the period from the time td2 to the time td3 is to cope with a low demand. From time td3, since the demand increases again, the output power of module A should increase accordingly. However, from calculation, the discharge depth of module A reaches 50% between time td2 and time td4. Therefore, thereafter, the module A only discharges at the output power (maximum 0.5 Ps, minimum 0.1 Ps) corresponding to the depth of discharge until time td6.
[0113]
It is predicted that the demand will increase again at time td4. As described above, since the discharge depth of module A already exceeds 50%, module A alone cannot cope with this. Therefore, at time td4, the module B is activated, and the module B discharges only the shortage of the module A.
[0114]
After that, since the demand is expected to gradually decrease, the output power from the power storage / distributed power supply system 20 is also reduced accordingly. Here, it is specified in the constraint that the module A is preferentially discharged. Therefore, the reduction of the output power is preferentially performed for the module B. The reason why the output power of the module A is reduced in accordance with the decrease in the demand is that even after the discharge from the module B is completely stopped, the power is still higher than the demand.
[0115]
Despite having made such an operation plan, there is a case where a demand different from the result of the sequential prediction and the result of the long-term prediction is predicted. In this case, the operation plan correction unit 38 issues a command to the power control unit 39 while appropriately correcting the operation plan. Here, a case where the demand is larger than the long-term forecast by the amount of power We1 and We2 in FIG. 12 will be considered as an example.
[0116]
The operation plan correction means 38 compares the result of the sequential prediction with the operation plan (or the long-term prediction result based on the operation plan). Then, time td3Unexpected power demand We1Is newly generated. Therefore, the operation plan correction means 38 sets the start timing time of the module B to the time td.4From td3Hasten. Also, regarding the module A, the output power after exceeding the discharge depth of 50% is made slightly larger than originally planned in consideration of the power demand We1.
[0117]
Also, at time td5From td6Unexpected power demand We2Has occurred. Therefore, the output power of the module B is kept higher than originally planned to cope with this.
[0118]
Next, an operation in response to an emergency will be described.
[0119]
In this embodiment, it is also possible to suppress a sudden change in the system frequency due to an abnormal load fluctuation such as a reverse power flow.
[0120]
In an emergency (for example, when the frequency fluctuation of the system detected by the system monitor 13 exceeds a certain fluctuation range), the power from the power storage / distributed power supply system 20 is provided to stabilize the system frequency.
[0121]
When the system frequency is lowered (that is, when the power supply is insufficient for the demand), the power is supplied from the modules A and B in order in accordance with the discharge priority condition or from both the modules A and B as necessary. Supply. In the present embodiment, the power amount Wxd is secured in the module B even during the time period when the power storage amount of the system is the smallest (time te-time ta in FIG. 11B). Therefore, even if an unexpected increase in power demand occurs, the situation can be dealt with.
[0122]
Conversely, when the system frequency increases (that is, when the power supply greatly exceeds the demand), power is charged to the modules B and A in order, or to both of the modules A and B as necessary. . Therefore, even in a time zone in which the amount of power stored in the system is the largest (time tb-time tc in FIG. 11B), the module A has a capacity that can be charged with the power amount Wxc. Therefore, it is possible to cope with a situation where the power demand unexpectedly decreases.
[0123]
As described above, in the present embodiment, by making and correcting the operation plan based on the demand forecast, it is possible to perform the peak cut power operation with high accuracy that follows the actual power demand. In addition, it is possible to improve the energy conversion efficiency of the secondary battery facility while supplying necessary power to the system.
[0124]
Further, by always securing a chargeable / dischargeable area, it is possible to sufficiently cope with an emergency.
[0125]
In this embodiment, the output power is adjusted based on the discharge depth of 50%. However, it goes without saying that a greater number of discharge depths serving as the reference may be set and more finely set. Alternatively, the output power limit may be set continuously according to the depth of discharge. In this way, operation with less power loss is possible. However, it is preferable to set an appropriate step size in consideration of ease of control, a calculation method for optimization and a time required for the optimization, a target of power loss reduction, accuracy of demand prediction, and the like.
[0126]
In the above description, only the discharging is mainly described. However, the charging current may be adjusted in accordance with the depth of discharge from the same viewpoint when charging. However, since charging is basically performed using surplus power, there are restrictions on charging time and the like. Therefore, the charging current may be determined with higher priority given to these various constraints.
[0127]
[Example 3]
The present 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 b.
[0128]
FIG. 14 shows a power supply system including the power storage / distributed power supply system 21 of this embodiment.
[0129]
Since the secondary battery equipment and the control-related components are configured with the same equipment as in the second embodiment, the description is omitted here.
[0130]
The fuel cell module 8 obtains DC power by electrochemically reacting air and fuel gas. The fuel cell module 8 is configured 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 b. The change of the output destination is performed by the switches 10c and 10d described later.1, 10d2It is performed by.
[0131]
The secondary battery modules 7a and 7b store the power generated by the fuel cell module 8 and release the stored power to the distribution system line 4. Unlike the above embodiment, the electric power generated by the power supply 1 is not stored in the secondary battery modules 7a and 7b. The charging can be performed efficiently because the DC output generated by the fuel cell module 8 can be performed directly (without performing direct / interchange conversion). Such a difference from the above embodiment is realized by peripheral circuits (for example, switches 10a to 10d, power converter 11 and the like), and the secondary battery modules 7a and 7b themselves are different from the above embodiment. May be the same as However, the maximum charging current densities of the secondary battery modules 7a and 7b are set higher than the current density output from the fuel cell.
[0132]
The auxiliary equipment 80 is various devices related to the fuel cell module 8 such as a fuel supply unit and a heater.
[0133]
The current / voltage detector 9c detects a current value and a voltage value of an output from the fuel cell module 8. The detection result is output to the power control system 31.
[0134]
The switch 10c is for connecting / disconnecting the fuel cell module 8 and the electric circuit of the power distribution system line 4. Switch 10d1, 10d2Is for connecting / disconnecting the secondary battery modules 7a, 7b and the fuel cell module 8 on the DC side. As already described, the switches 10c, 10d1, 10d2Is used to change the output destination (the power distribution system line 4, the secondary battery modules 7a and 7b) of the power generated by the fuel cell module 8.
[0135]
The DC voltage regulator 16 regulates the fuel cell power generation voltage.
[0136]
Each unit described above is configured to operate according to a command signal from the power control system 31.
[0137]
The power control system 31 basically controls the fuel cell module 8 and controls the cooperation between the fuel cell 8 and the secondary battery modules 7a and 7b in addition to the functions similar to those of the second embodiment. It has a function to perform. Hereinafter, the power control system 31 will be described in detail with reference to FIG.
[0138]
Although the basic configuration of the power control system 31 is the same as that of the power control system of the second embodiment, the functions of the respective functional sections are slightly different because the control of the fuel cell module 8 is also required. Therefore, the following description focuses on differences from the power control system in the second embodiment.
[0139]
The basic data stored in the basic data storage means 36 may be the same as in the above embodiment.
[0140]
From the input means 37, in addition to the same restrictions as in the above embodiment, various restrictions for protecting the fuel cell module are also input.
[0141]
The operation plan creation unit 34 has a function of determining an operation plan for satisfying the result of the long-term prediction by the power demand prediction unit 32. The “operation plan” in this 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 regard, the first , Different from the second embodiment). The operation plan is basically created from the viewpoint of performing the peak cut operation using the secondary battery modules 7a and b so as to minimize the output fluctuation of the fuel cell module 8. In this case, it is natural that the plan is created in consideration of the discharge depth of the secondary battery module 7 at that time (or when the operation plan is performed). The determination of the load distribution between the secondary battery modules 7a and 7b is performed from the same viewpoint as the creation of the operation plan in the second embodiment.
[0142]
To create an operation plan, it is necessary to know the power that must be output as the entire power storage and distributed power system. For that purpose, it is necessary to know the output power value expected by the power supply 1. Therefore, the operation plan creating unit 34 of the present embodiment inputs the operation plan of the power supply 1 and the like as the base power operation information 310.
[0143]
The operation plan correction means 38 appropriately corrects the operation plan according to the result of the sequential prediction by the demand prediction means 32. 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 frequently changed, the power generation efficiency is reduced and the life is reduced. However, it is needless to say that the output power of the fuel cell module 8 is corrected when the rechargeable battery modules 7a and 7b alone cannot cope.
[0144]
The power control unit 39 outputs various control signals 391 to 395 to control the fuel cell module 8 and the secondary battery modules 7a and 7b in accordance with an instruction from the operation plan correction unit 38. The fuel cell output adjustment signal 395 is for adjusting the output voltage of the fuel cell module 8, and is output to the DC voltage regulator 16. The switching operation command 391 is output to the switches 10a, 10b, 10c, 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 equipments 8a and 8b.
[0145]
The operation of this embodiment will be described with reference to FIG.
[0146]
The operation plan creating means 34 creates an operation plan in which the power Po supplied by the power supply 1 is subtracted from the power demand in the load 3 and the remainder is supplied by the power storage / distributed power supply system 21. Since the power Po is generally kept constant, the description of the operation of the power supply 1 of the system is omitted.
[0147]
In normal times, power is supplied from the fuel cell module 8 (or from both the fuel cell module 8 and the secondary battery module 7) to the power distribution system line 4 side. That is, during the daytime (time tc-time te), the power demand is large and the power is insufficient only with the fuel cell module 8, so the shortage Wd is discharged from the secondary battery modules 7a and 7b (see FIG. 16A). . Therefore, in this case, the power control means 391, 10d2Is an open circuit. The switches 10a, 10b, 10c are closed. On the other hand, during the nighttime (time ta-time tb), the demand decreases and the power remains, so the 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 includes the switches 10c and 10d.1, 10d2Is closed. The switches 10a and 10b are open circuits. The electric power (electric energy Wc) required to perform the peak cut operation in the daytime is covered by the electric power charged at this time. The load distribution between the secondary battery modules 7a and 7b is performed from the same viewpoint as in the second embodiment.
[0148]
As described above, in the present embodiment, the power supply 1 located at a higher position in the system can continue to operate at a constant output. In addition, the energy conversion efficiency of the secondary battery modules 7a and 7b can be kept high. Further, the fluctuation of the output of the fuel cell module 8 can be reduced (see FIG. 16B). If the secondary battery modules 7a and 7b have sufficiently large capacities, it is possible to operate the fuel cell module 7 while keeping the output constant. Furthermore, the higher the chargeable current density of the secondary battery modules 7a and 7b, the greater the flexibility with respect to fluctuations.
[0149]
Next, a description will be given of how to deal with a sudden change in the system load.
[0150]
Here, as shown in FIG. 17, a plurality of system feeders F branched from the power distribution system line 4 are provided.1~ FnConsider a case where the AC load group 23 is connected to each of them. Also, the system feeder F1~ FnHas a circuit breaker 5(1)~ 5(N)Shall be attached.
[0151]
In such a configuration, for example, the system feeder F3(For example, a ground accident), the system feeder F3Is a circuit breaker 5(3)Is immediately disconnected from the distribution system line 4. Then, the system feeder F3In this case, the frequency of the power distribution system line 4 rises sharply because the load 23 provided in the power supply system falls off (that is, the power demand sharply decreases).
[0152]
However, in the present embodiment, the operation plan correction means 38 detects an abnormality (in this case, an increase in frequency) based on a signal from the system monitor 13 and notifies the power control unit 39 of that. Then, the power control unit 39 stops the output from the secondary battery module 7 to the power distribution system line 4 by opening the switches 10a and 10b to respond to the abnormal state. At the same time, the switch 10d1, 10d2Is closed, and at least a part of the electric power output from the fuel cell module 8 is stored in the secondary cell module 7. Thus, the output of the power storage / distributed power supply system 21 can be reduced without lowering 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.
[0153]
A sudden reverse power flow from the system load group 3 can be dealt with in the same manner.
[0154]
Thereby, the fuel cell module 7 can continue to operate in a state where the facility operation rate is high. The upper power supply 1 is also less affected by load fluctuations in normal times and in emergency, so that it can be operated while maintaining a constant output with a high operation rate. The same effect can be obtained by employing a solar cell power generation facility instead of the fuel cell power generation facility.
[0155]
Next, as another example, a description will be given of an emergency response in a case where the power storage distributed power supply system 21 is provided between the loads of the system feeder as shown in FIG.
[0156]
System feeder FxIs a circuit breaker 5xIs connected to the power distribution system line 4 via the. And the system feeder Fx, An AC power load group 23 and a large number of switches 17 are connected. Further, the system feeder FxAre connected to the power storage / distributed power supply system 21 via a circuit breaker 50.
[0157]
System feeder FxIf an accident occurs in any part of the above, the power storage / distributed power supply system 21 provided in the section where the accident occurred is opened by opening the circuit breaker 5 and the system feeder FxMust be disconnected from In this case, the fuel cell module 8 of the power storage / distributed power supply system 21 may be forced to operate at an extremely low load. The output of the fuel cell cannot be reduced instantaneously, and a sudden change in load leads to a significant reduction in the life of the fuel cell equipment. However, in this embodiment, since the output of the fuel cell can be instantaneously redirected to the charging of the secondary battery modules 7a and 7b, such a situation can be obtained even if the output of the fuel cell module 8 is not suddenly reduced. Can be handled.
[0158]
Further, the circuit breaker 5 in FIG.xWhen an accident occurs between the switch and the switch 17b, power can be supplied to the load groups 23a and 23b from the power storage / distributed power supply system 21 disposed on the downstream side. Therefore, the power failure section can be made as small as possible.
[0159]
[Example 4]
This embodiment is characterized in that both the AC power and the DC power are supplied from the distributed power storage system 21 according to the present invention.
[0160]
FIG. 19 shows a power supply system including the power storage distributed power supply system according to the present embodiment. The power storage / distributed power system 21 itself basically has the same configuration as that of the second or third embodiment, but further includes a DC power output unit 45 in this embodiment.
[0161]
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 includes a switch connected to each battery module (secondary battery, fuel cell) and an output voltage regulator, and the like. The operation of the DC power output unit 45 is controlled by the power control system 30 or 31.
[0162]
The DC power system line 46 is a cable for guiding power to a DC power customer 47. In the present embodiment, it is buried underground to prevent a power failure due to a lightning strike.
[0163]
As the DC power consumer 47, for example, a charging station for an electric vehicle, a computer user, and the like are considered.
[0164]
In this embodiment, high-quality and highly reliable DC power can be efficiently supplied to DC power consumers.
[0165]
【The invention's effect】
As described above, according to the present invention, the energy conversion efficiency of a secondary battery can be improved. Further, it is possible to stabilize the supplied power even in the event of a sudden load change in an emergency.
[0166]
Further, the stability of the upper system power supply can be secured. This leads to an improvement in the operation rate of the upper system power supply.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a power storage / distributed power 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 the present embodiment.
FIG. 6 is a block diagram illustrating a power storage / distributed power 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 constituting the demand forecasting means.
FIG. 9 is a diagram illustrating an example of a constraint condition.
FIG. 10 is a graph showing a relationship between a depth of discharge and a rated power amount.
FIG. 11 is a graph showing an example of (a) a demand forecast result and (b) a peak cut operation performed on the demand forecast.
FIG. 12 is a diagram showing an example of a power distribution operation plan and its correction.
13 is a diagram showing load distribution for each module corresponding to the operation plan and correction of FIG.
FIG. 14 is a block diagram illustrating a power storage / distributed power 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 block diagram showing an example in which the distributed power storage system 21 according to the third embodiment is connected to a system bus having a plurality of system feeders.
FIG. 18 is an example in which the power storage distributed power supply system 21 of the third embodiment is provided between the loads of a system feeder and interconnected.
FIG. 19 is a block diagram of a power supply system that supplies DC power from the distributed power storage 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]
DESCRIPTION OF SYMBOLS 1 ... Power supply 2 ... Distribution substation 3 ... System load group 4 ... Distribution system 5 ... Circuit breaker 6 ... Transformer 7 ... Secondary battery module 8 ... Fuel cell Module 10 Switchgear 11 Power converter 12 Power control unit 14 Operation plan creation support means 16 DC voltage regulator 19 Power storage distributed power supply system 20 ... power storage distributed power supply system, 21 ... 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 correction means 39: power control means 45: DC power output Stage, 46 ...... DC power system line, 47 ...... DC power consumers

Claims (2)

  1. A plurality of secondary battery modules configured to include one or more secondary batteries,
    Parameter means for obtaining a value of a certain parameter having a correlation with the internal resistance of the secondary battery (hereinafter referred to as “parameter value”);
    Control means for adjusting the discharge power from the secondary battery module according to the parameter value obtained by the parameter means,
    The plurality of secondary battery modules are arranged in parallel with each other, and configured to be able to control charging and discharging independently of each other,
    The control means, a reference value of the parameter determined based on the relationship with the internal resistance,
    And a priority order between the secondary battery modules predetermined for charging and discharging, respectively,
    The adjustment is performed based on the magnitude relationship between the reference value and the parameter value obtained by the parameter means. In the region where the internal resistance is large, the discharge power is reduced, and That the above charging and discharging are performed according to the order,
    A power storage system characterized by the above-mentioned.
  2. The control means, when the power is insufficient only with the power discharged from the high-priority secondary battery module, is to permit discharge from the low-priority secondary battery module;
    The power storage system according to claim 1, wherein:
JP27223094A 1994-11-07 1994-11-07 Power storage system Expired - Fee Related JP3599387B2 (en)

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US8928288B2 (en) 2009-10-05 2015-01-06 Ngk Insulators, Ltd. Controller, controller network and control method

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