JP2005130550A - Method and system for generating distributed energy system operation plan - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To minimize a running cost, taking into consideration the balance among accumulation and release of energy and black out, when controlling operation by interconnecting a power grid with a distributed energy system. <P>SOLUTION: An facility data storage part 22 stores facility data such as nominal output and efficiency of equipment. An initial operation plan generating part 21 generates initial operation plan, based on the operation plan of the previous day. An operation plan correcting part 23 takes a demand prediction data from a demand predicting device 4, which predicts the amount of demanded electric power of the energy load on the day and corrects the operation plan to satisfy the demanded electric power amount. Further, the initial operation plan is so corrected as to minimize a running cost, while satisfying energy accumulation device restraints based, on the facility data of the facility data storage part 22, and the corrected initial operation plan is outputted as an optimum operation plan. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a distributed energy system having one or more energy generators and energy storage devices and connected to a power system and an energy load.

Currently, there is a power demand supply control system described in Patent Document 1 as a system that performs such control. This is because low-cost power generation is performed in a given area when distributing power to a plurality of power consumers including a power consumer with a distributed power source in a given area (community) and supplying and supplying power between these consumers. Reduce the cost by controlling the supply and demand by suppressing the amount of expensive purchased power from the electric utility, for example, by maximizing the use of the distributed power source and the energy storage equipment that stores energy, such as the power generation device of the customer Is intended.
Japanese Patent Laid-Open No. 2002-010506

  Here, there are charging devices, hydrogen tanks, hot water tanks, etc. as energy storage devices, but if you create an operation plan that minimizes running costs without balancing energy, you should use up all the energy in the energy storage device. Since the running cost is reduced, a plan in which no energy remains in the energy storage device is created in the last time zone of the operation plan. If an attempt is made to create the next operation plan in this state, even if there is a lot of energy demand in the initial time zone, energy is not stored in the energy storage device. Even in this case, there arises a problem that grid power must be purchased.

  In addition, when the power system in a predetermined area suddenly loses power and the power generation device is stopped, there is a case where power cannot be supplied to an important load described later unless an energy storage device has a certain capacity. .

  The present invention has been made in view of the above-described problems, and the object of the present invention is to take into account the balance of energy storage and discharge and power outages when operating a distributed energy system linked to a power system. Another object of the present invention is to provide a distributed energy system operation plan creation apparatus and creation method that minimizes running costs.

  The energy system operation plan creation device of the present invention has been modified by correcting the initial operation plan so as to minimize the running cost, and the initial operation plan creation means for creating an initial operation plan using past operation data. Operation plan correction means for outputting the initial operation plan as the optimum operation plan is provided.

  Specifically, the optimum operation plan correction means uses the method of solving the combination optimization problem for the initial operation plan created by the initial operation plan creation means, and the energy generator, the energy storage device, and the power in all time zones. The amount of energy supplied from the grid is the integrated value of the fuel cost, which is the cost for the energy generator to generate energy while satisfying the energy demand of the energy load, and the amount bought and sold at the power price of the power grid Correction is made to minimize the running cost, which is the sum of the grid power cost, and further, the energy storage device is corrected so that the amount of energy stored in the energy storage device is equal to the amount released, and the energy storage device is a certain amount. Make an optimal operation plan by modifying the energy storage device capacity to be always larger than the value.

  Therefore, an optimum operation plan that minimizes the running cost is created.

  Here, when an operation plan is created in which the amount of energy released within a certain period is greater than the accumulated amount, the amount of energy within the certain period is increased by increasing the accumulated amount within the capacity range of the energy storage device. The optimum operation plan is created while correcting the initial operation plan so that the energy storage amount and the discharge amount of the storage device become equal. In the process of increasing the amount of energy stored, when a storage battery is used as an energy storage device, the storage battery constraint conditions are set in order from the time when the power price is the lowest, in order to minimize the grid power cost. While satisfying, the optimum operation plan is created while updating the initial operation plan so as to increase the amount of charging power.

  When an operation plan is created in which the amount of energy stored in a certain period is greater than the amount released, the amount of energy stored in the specified period is increased by increasing the amount released in the energy storage device capacity range. The optimal operation plan is created while correcting the initial operation plan so that the amount and the discharge amount are equal. When a storage battery is used as an energy storage device in the process of increasing the released amount, the storage battery constraints are satisfied in order from the time when the power price is highest in order to minimize the grid power cost. However, the optimum operation plan is created while updating the initial operation plan so as to increase the discharge electric energy.

  The energy storage capacity for the amount of energy of the important load is calculated in advance so that the energy demand of the important load that requires constant energy supply can be satisfied for more than the required backup time using only the energy supplied from the energy storage device. The optimal operation plan is created so as to secure the energy storage capacity in any time zone.

  In this way, it is possible to cope with an emergency such as a power failure by always securing an important energy load.

  As described above, the present invention can keep the accumulated state by minimizing the running cost in consideration of the balance of energy, and when making the next operation plan by using the accumulated energy. The cost can be reduced for various situations.

  Next, embodiments of the present invention will be described with reference to the drawings.

  In the following embodiment, a genetic algorithm (hereinafter referred to as GA) is used as a technique for solving the optimization problem, but other techniques such as tab search and simulated annealing may be used.

  FIG. 1 shows a configuration of a distributed energy system including a distributed energy system operation plan creation device according to an embodiment of the present invention.

  The distributed energy system 1 includes a power generation device 11 and a heat generation device 12 as energy generation devices, an energy storage device 13 (for heat), an energy storage device 14 (for power), a power conversion device 15, and a server 16. And a distributed energy system operation plan creation device 17 and a control device 18.

  When a storage battery is used for the energy storage device 14 (for power), for example, a direct current from the power generation device 11 and the energy storage device 14 (for power) is converted into an alternating current by the power conversion device 15 and connected to the power system 3 when discharging. Thus, electric power is supplied to the energy load 2. Further, at the time of charging, the energy storage device 14 (for electric power) is charged by the power generated by converting the power from the power generation device 11 and the alternating current from the power system 3 into direct current by the power conversion device 15. Here, a gas turbine or the like may be used as the power generation device 11 in addition to a fuel cell, and a lead storage battery or a nickel hydrogen battery may be used as the energy storage device 14 (for power). Examples of the energy load 2 of electric power include lighting, air conditioning, and a home server. Further, in order to effectively use the exhaust heat of the power generation device, a hot water storage tank or the like is provided as the energy storage device 13 (for heat). It is assumed that the heat accumulated in the hot water storage tank is used in a bath or the like that is the heat energy load 2. The control device 18 performs the above-described control, and the control value is supplied from the server 16 to the distributed energy system operation plan creation device 17 that creates an operation plan for minimizing the running cost based on the demand prediction data and the operation data for the previous day. It is determined by the optimum operation plan value taken in. The server 16 stores demand forecast data, operation data for the previous day, and the like.

  FIG. 2 is a block diagram illustrating a configuration example of the distributed energy system operation plan creation device 17. The distributed energy system operation plan creation device 17 includes an initial operation plan creation unit 21, an equipment data storage unit 22, and an operation plan correction unit 23.

  The equipment data storage unit 22 stores equipment data such as the rated output and efficiency of the equipment. The initial operation plan creation unit 21 creates an initial operation plan based on the previous day's operation plan. The operation plan correction unit 23 takes in the demand prediction data from the demand prediction device 4 that predicts the demand power amount of the energy load of the day, corrects the initial operation plan so as to satisfy the demand power amount, and further, the equipment data storage unit The initial operation plan was revised to minimize the running cost while satisfying the energy storage device constraint conditions (conditions such as not releasing energy when the capacity of the energy storage device reached the lower limit) based on the 22 equipment data. The initial operation plan is output to the control device 18 as the optimum operation plan.

  If the operation plan is performed in units of one hour, for example, combinations of 24 operation command values can be considered as shown in FIG. When thinking about how to make this command value the power price or how to satisfy the load power, there are a huge number of combinations, so efficiently search for a solution that seems to be good to some extent. I have to go. Metaheuristics is a method of finding the combination with an algorithm of each method. For example, in GA, an operation plan is compared to a gene sequence. Although FIG. 6 shows a gene arrangement, a good individual (driving plan) survives in nature, and a bad one is deceived (natural selection). There are several different individuals in the same generation, and a good individual is selected by natural selection. Leave the good solid in the next generation, and then create a new individual with reference to the good individual (crossover, Fig. 7), or create a good individual by mutation (Fig. 8). Ask.

  Next, FIG. 3 shows a flowchart of initial operation plan creation in the initial operation plan creation unit 21. In this example, the driving pattern of the previous day is read from the server 16 (step 101), an initial gene is created (step 102), and an initial driving plan is created. Alternatively, an average value for one month, an average value for each past day of the week, or the like may be used.

  FIG. 4 shows a flowchart of the operation plan update in the operation plan correction unit 23 of FIG. In this example, genes are crossed or mutated so as to satisfy the predicted power demand for the energy load of the day from the initial gene creation data obtained in the initial operation plan creation unit 21 based on the previous day's operation data. If the integrated value of the charge / discharge power amount (with the charge power amount minus and the discharge power amount plus) within a certain period is not 0 by this operation, it is set to 0. (Step 202) (This is said to balance charging and discharging, and a specific example of balancing will be described later). After balancing the charge and discharge, the fitness of each gene is calculated (step 203), and natural selection is made according to the fitness (step 204). Here, the degree of conformity is defined as in equation (1), for example.

Goodness of fit = 1 / running cost (1)
Also, the running cost is defined as shown in equation (2), for example. Note that Σ means that the running cost for one day is integrated, and generated power and charge / discharge power are output in consideration of efficiency, and examples of unit prices for buying and selling are shown in FIGS.

Running cost = Σ [(load power−generated power−charge / discharge power) × unit price for buying and selling power + fuel cost for generating power and heat] (2)
After performing these operations, in the convergence determination (step 205), the solutions that have the minimum running cost in a certain generation are not updated, or they have converged after a certain period of time. An operation plan with a low running cost is selected as the optimum operation plan (step 206).

  Here, the energy balancing (step 202) in FIG. 4 will be described. As an example, FIG. 5 shows a processing flow for balancing charge and discharge in a storage battery. After genetic manipulation such as crossover and mutation, the balance of charge and discharge within a certain period may be lost. In step 301, when the amount of discharge power is large, the charge power amount is increased sequentially from the time zone with the lowest price of the system power, and the minimum load power is supplied so that it can be supplied to the important load power when the power system fails. The capacity is secured (described in FIG. 13 described later), and the charge / discharge electric energy is calculated so that the charge / discharge balance within a certain period can be achieved (steps 302 to 304). If charge / discharge balance is achieved, the battery capacity should be checked against overcharge and overdischarge. If overcharge or overdischarge has occurred, the charge / discharge power amount is recalculated so that the charge / discharge amount falls within the storage battery capacity range (steps 308 to 310). If not, the convergence determination (step 205) is performed. Shall move. Similarly, when the amount of discharge power is small, increase the discharge power sequentially from the time when the grid power is most expensive, and move to convergence judgment while considering the minimum load capacity, charge / discharge balance, overcharge and overdischarge. (Steps 305 to 310). Here, the charge / discharge power amount indicates an output from the storage battery in units of one hour, and the charge / discharge amount indicates an integrated value for 24 hours of the charge / discharge power amount.

  Next, an example of a method for making an operation plan a gene sequence will be described. FIG. 6 shows the output of the fuel cell as the power generation apparatus 11 in 6 stages, 1 to 6 and the output of the storage battery 14 in charge 1 to -8, discharge 1 to 8, and no charge / discharge as 0 to 17 stages. It is an example. In this way, the day is divided into 24 equal parts, and the operation plan of the power generator 11 and the storage battery 14 is output for each time zone.

  Next, an example of crossover will be described. For example, FIG. 7 divides the operation plan of FIG. 6 into two, 0-12 o'clock and 12-24 o'clock. The operation plan at 0-12 o'clock is A, the operation plan at 12-24 o'clock is B, the individual 1, the operation plan at 0-12 o'clock is C, the operation plan at 12-24 o'clock is D, and the individual 2 To do. Here, a new individual 3 and an individual 4 are obtained by exchanging B of the individual 1 and D of the individual 2. Crossover is performed in this way.

  Next, an example of mutation will be described. For example, FIG. 8 is an operation plan of the fuel cell of FIG. 6, and one time zone in which the output is changed is selected at random, and the output is increased or decreased at random. In FIG. 8, the output from 0 o'clock to 1 o'clock is changed from 6 to 4. If an operation plan value that does not fall within the output range of the fuel cell is created as a result of the mutation, it is deleted.

  Even if the output is changed only by these crossovers and mutations, there is no problem with the fuel cell, but the charge / discharge balance within a certain period is not achieved in the storage battery. Therefore, the discharge output is + (plus) and the charge output is-(minus), and the charge / discharge integrated value within a certain period is corrected to 0 (zero). For example, in FIG. 9, which is a modified example, the operation plan at 0-12 o'clock is output 1, and the operation plan at 12-24 o'clock is -1. The sum of the output values for each time zone of these energy storage devices 14 is zero.

  The charging / discharging of the storage battery in consideration of the price range will be described. For example, when the power purchase unit price, which is the price purchased from the power system 3, is as shown in FIG. 10, and the power sale unit price, which is the price for selling power by reverse flow, is as shown in FIG. In the vicinity of 15:00, system power is not purchased as much as possible, and output from the fuel cell or storage battery reduces the running cost. In addition, since the minimum value is around 3 o'clock in the middle of the night, the running cost is reduced by purchasing the grid power and supplying it to the energy load 2 or charging the storage battery without outputting from the fuel cell or storage battery. At this time, an operation plan outside the constraint range such as overdischarge is excluded, and an operation plan having a minimum running cost within the constraint range is selected as the optimum operation plan. 10 and 11 are priced like a sine wave as an example, but any price can be set.

  FIG. 12 shows an operation plan of the fuel cell and the storage battery, which is a result example calculated based on these. The upper part is an operation plan for the fuel cell, and the lower part is an operation plan for the energy storage device 14. The vertical axis represents each output power value, and the horizontal axis represents the time axis. In addition, the plus of charging / discharging power of the energy storage device 14 indicates the amount of discharging power, and the minus indicates the amount of charging power. In this example, both the power generation device 11 and the energy storage device 14 generate power during the daytime when the power demand is high, and the energy storage device 14 is charged without generating power from the power generation device 11 at midnight when the power demand is low.

  A method of securing the minimum load power capacity so that important load power can be supplied when the power system in FIG. FIG. 13 shows a control flowchart when a power failure occurs in the system power. An important load power amount to be supplied to an important load that must be constantly supplied, such as some lights and home servers, is input in advance (step 401). The important load electric energy is the electric energy that can cover the electric energy of the important load only by the storage battery 14 in the time (backup time) from the power failure to the start of the power generation device, and the storage battery 14 always uses this electric energy. Calculate to keep. As a result, if the power generation device 11 is activated after a power failure occurs, power is supplied from the power generation device 11 to the important load (steps 402 to 404). Can be supplied (steps 402, 403, and 405), and after the power generation device 11 is started (step 406), power is supplied from the power generation device 11 to the important load (step 407). Power can be supplied. After the power failure recovery, the power is supplied from the power system 3, the power generator 11, and the storage battery 14 to the load as usual. At this time, an important load that is a power supply destination from the power generation device 11 and the storage battery 14 at the time of a power failure is set in advance.

It is a lineblock diagram of a distributed energy system which has a distributed energy system operation plan creation device of one embodiment of the present invention. It is a block diagram which shows the structure of the distributed energy system operation plan preparation apparatus 17 in FIG. It is a flowchart which shows the process of the initial stage operation plan preparation part 21 in FIG. It is a flowchart which shows the process of the driving plan correction part 23 in FIG. 5 is a flowchart showing details of energy balancing in FIG. 4. The example which made the arrangement | sequence of the fuel cell and the storage battery the operation plan is shown. It is a figure which shows an example of crossover. 8 shows an example in which a part of the operation plan of the fuel cell in FIG. 7 is mutated. An example in which the integrated value of charge / discharge within a certain period is set to 0 is shown. An example of power purchase unit price is shown for each time series. An example of the power selling unit price is shown for each time series. The example of the result of having calculated the operation plan of a fuel cell and a storage battery is shown. FIG. 6 is a flowchart of a process for securing a minimum load power capacity so that important load power can be supplied when the power system in FIG. 5 fails.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Distributed energy system 2 Energy load 3 Electric power system 4 Demand prediction apparatus 11 Electric power generation apparatus 12 Heat generating apparatus 13 Energy storage apparatus (for heat)
14 Energy storage device (for electric power)
DESCRIPTION OF SYMBOLS 15 Power converter 16 Server 17 Distributed energy system operation plan preparation apparatus 18 Control apparatus 21 Initial operation plan preparation part 22 Equipment data storage part 23 Operation plan correction part 101-102, 201-207, 301-310, 401-407 Step

Claims (12)

In a distributed energy system having one or more energy generators and energy storage devices and connected to a power system and an energy load,
An initial operation plan creation means for creating an initial operation plan using past operation data;
The initial operation plan created by the initial operation plan creation means is converted into the energy supply amount from the energy generation device, the energy storage device, and the power system in all time zones by using a method for solving a combination optimization problem. While satisfying the energy demand of the load, the sum of the fuel cost, which is the cost that the energy generating device generates when generating energy, and the grid power cost, which is the integrated value of the amount bought and sold at the power price of the grid The energy storage device is modified so as to minimize a running cost, and is further modified so that the energy storage amount and the discharge amount of the energy storage device are equal within a certain period, and the energy storage device stores energy exceeding a certain value. Modify the operation plan so that the equipment capacity is always secured, and create an optimal operation plan. Distributed energy system operation plan creating apparatus for.   In the operation plan search process for minimizing the running cost, the operation plan correction means, when an operation plan in which the amount of released energy within a certain period is greater than the accumulated amount is created, Create an optimal operation plan while modifying the initial operation plan so that the energy storage amount and the discharge amount of the energy storage device within a certain period become equal by increasing the storage amount within the capacity range. The distributed energy system operation plan creation device according to claim 1.   When the storage plan is used as an energy storage device in the process of increasing the amount of stored energy, the operation plan correcting means has the lowest power price in order to minimize the system power cost. 3. The distributed energy system operation according to claim 2, wherein the optimum operation plan is created while updating the initial operation plan so as to increase the amount of charging electric power while sequentially satisfying the storage battery constraint condition from the time zone. Planning device.   In the operation plan search process for minimizing the running cost, the operation plan correction means is configured such that when an operation plan in which the amount of accumulated energy in a certain period is larger than the released amount is created, the energy storage device capacity range The optimal operation plan is created while correcting the initial operation plan so that the stored amount and the released amount of the energy storage device within a certain period become equal by increasing the released amount within Item 2. The distributed energy system operation plan creation device according to Item 1.   When the storage plan is used as an energy storage device in the process of increasing the release amount, the operation plan correcting means is configured to minimize the grid power cost so that the time when the power price is the highest. 5. The distributed energy system operation plan according to claim 4, wherein the optimum operation plan is created while updating the initial operation plan so as to increase the discharge electric energy while satisfying the storage battery constraint condition sequentially from the belt. Creation device.   The operation plan correction means satisfies an energy demand of an important load that always requires energy supply for the operation plan search process for minimizing the running cost for more than the backup time required only by the energy supplied from the energy storage device. The energy storage capacity corresponding to the energy amount of the important load is calculated in advance so that the energy storage capacity can be ensured in any time zone, and an optimal operation plan is created. Distributed energy system operation plan creation device. In a distributed energy system having one or more energy generators and energy storage devices and connected to a power system and an energy load,
An initial operation plan creation stage for creating an initial operation plan using past operation data;
The initial operation plan created in this initial operation plan creation stage uses the method of solving the combinatorial optimization problem, and the energy supply amount from the energy generator, energy storage device, and power system in all time zones is the energy supply amount. It is the sum of the fuel cost, which is the cost of the energy generating device generating energy while satisfying the energy demand of the load, and the grid power cost, which is the integrated value of the amount bought and sold at the power price of the grid The energy storage device is modified so as to minimize the running cost, and is further modified so that the energy storage amount and the discharge amount of the energy storage device are equal to each other within a certain period. The operation plan modification stage, in which the capacity is constantly secured and the optimum operation plan is created Distributed energy system operation planning how to.   In the operation plan correction step, in the operation plan search process that minimizes the running cost, when an operation plan in which the amount of released energy within a certain period is larger than the accumulated amount is created, the energy storage device Create an optimal operation plan while modifying the initial operation plan so that the energy storage amount and the discharge amount of the energy storage device within a certain period become equal by increasing the storage amount within the capacity range. The distributed energy system operation plan creation method according to claim 7.   In the operation plan correction stage, when a storage battery is used as an energy storage device in the process of increasing the amount of stored energy, the power price is the lowest so that the system power cost is minimized. The distributed energy system operation according to claim 8, wherein the optimum operation plan is created while updating the initial operation plan so as to increase the amount of charging power while satisfying the storage battery constraint condition sequentially from the time zone. Planning method.   In the operation plan correction stage, in an operation plan search process that minimizes the running cost, when an operation plan in which the amount of accumulated energy in a certain period is larger than the released amount is created, the energy storage device capacity range The optimal operation plan is created while correcting the initial operation plan so that the stored amount and the released amount of the energy storage device within a certain period become equal by increasing the released amount within Item 8. A distributed energy system operation plan creation method according to Item 7.   In the process of correcting the operation plan, in the process of increasing the release amount, when a storage battery is used as an energy storage device, the time when the power price is the highest in order to minimize the grid power cost. The distributed energy system operation plan according to claim 10, wherein the optimum operation plan is created while updating the initial operation plan so as to increase the discharge electric energy while satisfying the storage battery constraint condition sequentially from the band. How to make.   In the operation plan correction stage, in the process of searching for an operation plan that minimizes the running cost, the energy demand of an important load that always requires energy supply is satisfied more than the backup time required only by the energy supplied from the energy storage device. The energy storage capacity corresponding to the amount of energy of the important load is calculated in advance so that the energy storage capacity can be secured in any time zone, and an optimal operation plan is created. Decentralized energy system operation plan creation method.

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