JP2016040997A - Energy management system, power supply and demand plan optimization method, and power supply and demand plan optimization program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an energy management system, power supply and demand plan optimization method, and power supply and demand plan optimization program capable of shortening a time until an optimum solution is obtained.SOLUTION: An energy management system 20 comprises: a supply and demand plan calculation unit 22b for obtaining an optimum solution for a supply and demand plan including control values for an apparatus at a plurality of times in a plan period that is a given period from calculation time, by solving an optimization problem of an objective function that is an optimization index; and an initial value creation unit 22a for creating an initial value for searching in the supply and demand plan calculation unit 22b solving the optimization problem. The supply and demand plan calculation unit 22b updates the optimum solution for the supply and demand plan by repeatedly solving the optimization problem in an interval shorter than the plan period. The initial value creation unit 22a creates an initial value component for searching corresponding to at least one time in the plan period, on the basis of at least one of optimum solutions obtained before the calculation by the supply and demand plan calculation unit 22b.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an energy management system, a power supply / demand plan optimization method, and a power supply / demand plan optimization program.

  As described in Patent Document 1, a power supply system including a power generation system that is a solar power generator and an electric load and connected to an external power system is known. This system includes a charge / discharge plan control unit. The charge / discharge plan control unit calculates a predicted power amount of the electric load calculated based on the usage history of the power load and a predicted power generation amount of the power generation system predicted by the weather prediction. The charge / discharge plan control unit calculates a predicted consumption schedule indicating a transition of power consumption of the electric load for each hour and a predicted power generation schedule indicating a transition of power generation of the power generation system for each hour. The charge / discharge plan control unit determines a predicted power storage amount based on the predicted power amount and the predicted power generation amount, and determines a charge / discharge plan based on the predicted consumption schedule and the predicted power generation schedule.

  The charge / discharge plan control unit compares the predicted value based on the charge / discharge plan with the actually measured value based on the transition of the storage amount. The charge / discharge plan control unit calculates a difference between the predicted value and the actually measured value, and determines whether or not the difference is within the allowable value range. When the difference is outside the allowable value range, the charge / discharge plan control unit calculates the predicted consumption schedule and the predicted power generation schedule again, and newly determines the charge / discharge plan.

JP 2012-222860 A

  By the way, the microgrid which consists of a renewable energy generator, a private generator, the electrical storage possible facility, and a load is examined. As the renewable energy generator, a solar power generator or a wind power generator may be employed. A storage battery, an electric vehicle, or the like can be adopted as the facility capable of storing electricity. This microgrid is connected to an external system. The energy management system provided in the macro grid has a function of controlling the private power generator and the power storage facility. The energy management system optimizes the supply and demand plan for a certain period in the future with some index (for example, grid operation cost) as an objective function.

  The information (parameter) that serves as input for the supply and demand plan optimization is, for example, the above-described current value of the device, the predicted value of the power generation amount, or the predicted value of the demand amount. Since the predicted value and the actual value (current value) do not necessarily match, it is necessary to update the supply and demand plan by regularly reflecting the latest parameters during operation of the energy management system. The shorter the update interval of the supply and demand plan, the better. However, it is necessary to reduce the time required for the optimization calculation.

  In the optimization problem of supply and demand planning, it is difficult to directly obtain an optimal solution by an analytical method (so-called formula modification). Therefore, an optimal solution is obtained by performing a so-called iterative calculation in which some initial value is set and this initial value is gradually improved to approach the optimal solution. In the above-described conventional technique, although the supply and demand plan is updated based on the latest measured value (current value) and predicted value, there is no mention of how to determine the initial value. Therefore, depending on the setting of the initial value when solving the optimization problem, the time required to obtain the optimum solution can be long. From such a background, it is required to shorten the time until an optimal solution is obtained.

  An object of the present invention is to provide an energy management system, a power supply and demand plan optimization method, and a power supply and demand plan optimization program that can shorten the time required to obtain an optimal solution.

  The present invention provides energy management for optimizing energy supply and demand plans in a microgrid that includes a power-controllable device including a power storage device, a generator that generates power using renewable energy, and a load, and that is connected to an external power system By solving the optimization problem of the objective function, which is an optimization index, the system can find the optimal solution for supply and demand plans including control values for equipment at multiple times within the planning period, which is a fixed period from the time of calculation. A supply and demand plan calculation unit, and an initial value generation unit that generates an initial value for search when the optimization problem is solved in the supply and demand plan calculation unit. The supply and demand plan calculation unit is optimal at intervals shorter than the plan period. By resolving the optimization problem, the optimal solution for the supply and demand plan is updated, and the initial value generation unit uses the optimal solution obtained before the calculation by the supply and demand plan calculation unit. Based on at least one, and generates an initial value component of the search corresponding to at least one time within the planning horizon.

  According to this energy management system, the optimization function of the objective function, which is an optimization index, is solved by the supply and demand plan calculation unit. The supply and demand plan calculation unit obtains an optimal solution of the supply and demand plan including control values for the devices at a plurality of times within a planning period that is a fixed period from the time of calculation. In order to solve the optimization problem of the objective function, it is necessary to give an initial value, but an initial value for search is generated by the initial value generation unit. Here, the initial value generation unit generates an initial value for the search based on at least one of the optimal solutions obtained before the calculation by the supply and demand plan calculation unit. The time change of the parameter (for example, the predicted value of the amount of power generated by the generator) affecting the microgrid supply and demand plan is basically gentle. Therefore, the time change of the optimal solution component corresponding to each time within the planning period is also gradual. For this reason, even when time passes and optimization calculation is performed again, the optimum solution component corresponding to each time within the planning period of the obtained optimum solution is considered to be a value close to the already obtained optimum solution component. Therefore, even when performing so-called iterative calculations by generating the initial value of the search in the vicinity of the optimal solution of the new optimization problem based on at least one of the optimal solutions obtained before the calculation. The time to obtain the optimal solution can be shortened.

  In some aspects, the initial value generation unit is based on the optimal solution component corresponding to the specific time within the planning period of the optimal solution obtained before the calculation by the supply and demand plan calculation unit. The initial value component of the corresponding search is generated. As a result, the initial value of the search for a new optimization problem can be set in the vicinity of the optimal solution and the calculation can be started, and the optimal solution can be obtained in a short time.

  In some aspects, the initial value generation unit is configured to search for an optimal solution component corresponding to a specific time of an optimal solution obtained before calculation by the supply and demand plan calculation unit, and an initial value of a search corresponding to the specific time Ingredients. As a result, the initial value of the search for a new optimization problem can be set in the vicinity of the optimal solution and the calculation can be started, and the optimal solution can be obtained in a short time.

  In some aspects, the initial value generation unit determines whether or not there is an optimal solution component corresponding to each time within the planning period obtained before the calculation by the supply and demand plan calculation unit, and the optimal solution component is For the time determined not to exist, an initial value component corresponding to the time is generated based on the obtained optimum solution component corresponding to one or more times before the time. In this case, the initial value generation unit determines whether or not there is an optimal solution component corresponding to each time within the planning period of the optimal solution obtained before the calculation by the supply and demand plan calculation unit. When the initial value generation unit determines that there is no already obtained optimal solution component at a certain time, an initial value corresponding to the time based on a component corresponding to a single time or a plurality of times before the time among the obtained optimal solutions Generate value components. In the microgrid, since the transition of the control value of the device (which is an independent variable in the optimization problem) is not random and is considered to have a certain degree of smoothness, it can be optimized by using the above method. A reasonable estimate of the solution component (value set as the initial value) is obtained. Therefore, the initial value component at the time can be rationally set using the above-described concept even at a time when there is no obtained optimal solution component within the planning period, and the optimal solution can be obtained in a short time.

  The present invention provides a power supply and demand that optimizes an energy supply and demand plan in a microgrid that includes a power-controllable device including a power storage device, a generator that generates power using renewable energy, and a load, and that is connected to an external power system An initial value generation step in which an energy management system generates an initial value for searching an optimization problem of an objective function that is an optimization index, and an energy management system generates in an initial value generation step. A supply and demand plan calculation step for obtaining an optimal solution of a supply and demand plan including control values for devices at a plurality of times within a planning period that is a fixed period from the time of calculation by solving an optimization problem using the determined initial value, The energy management system repeats the supply and demand plan calculation step at intervals shorter than the planning period. In the initial value generation step, the search corresponding to at least one time within the planning period is based on at least one of the optimal solutions obtained before the supply and demand plan calculation step following the initial value generation step. The initial value component of is generated. According to this electric power supply and demand plan optimization method, the same operation effect as the above-mentioned energy management system is produced.

  The present invention provides an energy supply and demand plan optimal for an energy management system in a microgrid that includes a power-controllable device including a power storage device, a generator that generates power using renewable energy, and a load, and that is connected to an external power system. A power supply and demand plan optimization program that enables the energy management system to solve the objective function optimization problem, which is an optimization index, and solves equipment at multiple times within the planning period, which is a fixed period from the time of calculation. A supply-demand plan calculation unit that obtains an optimal solution of a supply-demand plan including control values for the supply-demand plan calculation unit that updates the optimal solution of the supply-demand plan by repeatedly solving the optimization problem at intervals shorter than the planning period; An initial value generation unit for generating an initial value of a search when an optimization problem is solved in a supply and demand plan calculation unit. An initial value generation unit that generates an initial value component of a search corresponding to at least one time within the planning period, based on at least one of the optimal solutions obtained before the time of calculation by the supply and demand plan calculation unit; To function. According to the power supply / demand plan optimization program, the same effects as the energy management system and the power supply / demand plan optimization method described above are exhibited.

  According to the present invention, it is possible to shorten the time until an optimum solution is obtained.

It is a block diagram which shows schematic structure of the electric power supply system to which the energy management system of one Embodiment of this invention was applied. It is a functional block diagram of the energy management system in FIG. It is a flowchart which shows the process performed in the energy management system of FIG. It is a flowchart which shows the supply-and-demand plan optimization process in FIG. It is a figure for demonstrating the initial value setting in the supply-and-demand plan calculation process implemented repeatedly. It is a figure which shows notionally the example which uses the obtained optimal solution component as an initial value component of the search in a new optimization problem. It is a figure which shows the storage medium in which the electric power supply-and-demand plan optimization program of one Embodiment of this invention was stored.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted.

  With reference to FIG. 1, the power supply system 1 to which the energy management system according to the present embodiment is applied will be described. As shown in FIG. 1, the power supply system 1 includes a microgrid G including a plurality of types of generators and power consuming devices, and an energy management system 20 that calculates control values of the devices in the microgrid G. Prepare. In the following description, “energy management system” is abbreviated as “EMS”. In FIG. 1, a solid line arrow indicates the flow of electricity, and a broken line arrow indicates the flow of information.

  The power supply system 1 can be used by a consumer who owns a building or a factory, for example. The power supply system 1 can be used by, for example, a power sales company that owns a renewable energy generator. The EMS 20 provides an optimized energy supply and demand plan to such a consumer or a power sales company.

  The microgrid G includes a renewable energy generator 5 including a solar power generator 3 and a wind power generator 4, and a prime mover 7 that generates power using fossil fuel. For example, a gas turbine can be used as the prime mover 7. Further, a gas turbine for cogeneration can be used as the prime mover 7. The microgrid G further includes a load 6 that consumes power in the microgrid G, and an electric vehicle (power storage device) 8 that travels using the power in the microgrid G. The load 6 may include a plurality of devices that consume power. The electric vehicle 8 includes a storage battery (not shown) and can store and discharge electric power. The electric vehicle 8 may include a charging station, for example. The microgrid G further includes a storage battery (power storage device) 9 capable of storing and discharging electric power. As the storage battery 9, a lithium ion battery can be used, for example. The microgrid G includes a grid control device 10 to which the plurality of power devices described above are electrically connected. The grid control device 10 is connected to the external power system 2. In other words, each of the plurality of power devices described above is connected to the external power system 2 via the grid control device 10.

  The electric power used in the microgrid G is covered by the renewable energy generator 5 or the prime mover 7, the electric vehicle 8 or the storage battery 9. In addition, in the microgrid G, it is possible to purchase power (that is, purchase power) from the external power system 2 or sell power (that is, sell power) by a reverse flow to the external power system 2. In general, the power purchase price depends on the contract with the power company, but in the present embodiment, it is assumed that the power purchase price changes depending on the time zone. The power selling price is defined by, for example, the “Special Measures Law concerning Renewable Energy Electricity Procurement by Electric Power Companies”. The power purchase price or the power sale price may be determined separately from the above system.

  The grid control device 10 includes hardware such as a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory), and software such as a program stored in the ROM. The grid control device 10 comprehensively controls power devices connected to the grid control device 10. The grid control device 10 includes a control circuit and a storage battery for controlling the flow of electricity. The grid control device 10 controls received power from the external power grid 2 and reverse power flow to the external power grid 2. The grid control device 10 and each power device can perform information communication with each other. The grid control device 10 acquires information on the current state of each power device. The grid control device 10 outputs a control value to each power device. The grid control device 10 stores information about each acquired power device. The grid control device 10 transmits information regarding each power device to the EMS 20.

  Among the power devices of the grid control device 10 described above, the prime mover 7, the electric vehicle 8, and the storage battery 9 correspond to devices whose output can be controlled by the grid control device 10.

  The EMS 20 is a computer configured by hardware such as a CPU, a ROM, and a RAM, and software such as a program stored in the ROM. The EMS 20 includes a power supply and demand plan optimization program 120 described later. The EMS 20 and the grid control device 10 can perform information communication with each other. The EMS 20 and the grid control device 10 may be communicable via the Internet, or may be communicable via a wired or wireless LAN. The EMS 20 has a function of calculating a control value for each power device in the microgrid G. In other words, the EMS 20 controls each power device in the microgrid G through the grid control device 10 by transmitting a control value to the grid control device 10.

  More specifically, the EMS 20 optimizes an energy supply and demand plan for a certain period in the future in the microgrid G using a certain index as an objective function. As an optimization index, that is, an objective function, for example, grid operation costs, that is, electricity charges are minimized during a planning period (for example, one day), received power fluctuation amount is minimized during a planning period, and emission CO2 is minimized. Can be mentioned. The EMS 20 calculates the supply and demand plan by solving the optimization problem of the objective function. The objective function may be an index other than the above three indices. The index used as the objective function is not particularly limited. The objective function may be defined by a weighted sum of a plurality of objective functions.

Examples of the independent variable of the objective function include variables shown in Table 1 below. The independent variable may be anything as long as it can be controlled in the microgrid G. The number of prime movers 7, electric vehicles 8, and storage batteries 9, which are controllable devices in the microgrid G, may be arbitrary as long as it is 1 or more as a whole, and may have different performance for each device.

  On the other hand, the power supply system 1 includes a demand / power generation amount prediction database 12 that stores a predicted amount of power demand and power generation amount in the microgrid G. The EMS 20 and the demand / power generation amount prediction database 12 can perform information communication with each other. The EMS 20 acquires the demand power generation amount and the power generation amount prediction value at a specific date and time from the demand / power generation amount prediction database 12. The demand power amount and the predicted value of the power generation amount stored in the demand / power generation amount prediction database 12 are periodically updated.

  The EMS 20 includes the latest information (for example, device status) regarding each power device of the microgrid G acquired from the grid control device 10 and the latest information regarding the power generation amount and the power demand amount acquired from the demand / power generation amount prediction database 12 ( For example, the supply and demand plan is corrected (that is, the supply and demand plan is updated) based on the predicted value and the like. Information (for example, device status) regarding each electric power device of the microgrid G and / or information (for example, predicted value) regarding the power generation amount and the power demand amount are used as parameters in the calculation of the supply and demand plan. That is, the parameter includes a current value or a predicted value related to at least one of the renewable energy generator 5, the prime mover 7, the storage battery 9, and the load 6. Specific parameters include, for example, various parameters shown in Table 2 below.

上表において、ＳＯＣは充放電状態（Ｓｔａｔｅ ｏｆ Ｃｈａｒｇｅ）を意味し、満充電の状態を１００％としたときの充電率を表す。ＰＣＳはパワーコンディショナ（Ｐｏｗｅｒ Ｃｏｎｄｉｔｉｏｎｉｎｇ Ｓｕｂｓｙｓｔｅｍ）を意味する。

In the above table, SOC means a charge / discharge state (State of Charge), and represents a charging rate when the fully charged state is 100%. PCS stands for Power Conditioning Subsystem.

  In the microgrid G, the independent variables and parameters depend on how the optimization problem is constructed, and therefore cannot be uniquely determined for the same grid. For example, if charging / discharging power of the storage battery 9 is an independent variable, the SOC becomes a dependent variable. On the other hand, when the SOC is an independent variable, a formulation with the charge / discharge power of the storage battery 9 as a dependent variable is also possible.

  The EMS 20 calculates the value of an independent variable that minimizes the objective function under given constraints in the calculation of the supply and demand plan. For example, the EMS 20 calculates the generated power at each time in the prime mover 7 by solving the optimization problem of the objective function. The EMS 20 calculates charge / discharge power at each time in the electric vehicle 8. The EMS 20 calculates the charge / discharge power at each time in the storage battery 9. The EMS 20 calculates the received power at each time of purchase from the external power system 2 depending on the generated power of the prime mover 7, the charge / discharge power of the electric vehicle 8, and the charge / discharge power of the storage battery 9.

  A functional configuration of the EMS 20 will be described with reference to FIG. The EMS 20 includes an overall control unit 20a, a communication unit 21, a calculation unit 22, a storage unit 23, and a display unit 24. The overall control unit 20a performs overall control of processing in the EMS 20. For example, the overall control unit 20a sequentially determines whether or not it is a supply and demand plan calculation time. The communication unit 21 is an input / output unit that performs information communication with the grid control device 10 and the demand / power generation amount prediction database 12. The calculation unit 22 calculates a supply and demand plan.

  The calculation unit 22 includes an initial value generation unit 22a, a supply / demand plan calculation unit 22b, a supply / demand plan adoption determination unit 22c, and a display control unit 22d. The initial value generation unit 22a generates an initial value for search when the optimization problem is solved in the supply and demand plan calculation unit 22b. The supply and demand plan calculation unit 22b calculates a supply and demand plan by solving the optimization problem. More specifically, the supply and demand plan calculation unit 22b obtains an optimal solution for the supply and demand plan at a plurality of times within a plan period that is a fixed period from the time of calculation by solving the optimization problem. This optimal solution includes control values for devices capable of output control such as the prime mover 7, the electric vehicle 8, and the storage battery 9. Further, the supply and demand plan calculation unit 22 b acquires parameters from the grid control device 10 and the demand / power generation amount prediction database 12. The supply / demand plan adoption determination unit 22c determines whether the supply / demand plan calculated by the supply / demand plan calculation unit 22b is adopted. The supply / demand plan acceptance / rejection determination unit 22c stores the supply / demand plan in the supply / demand plan storage unit 23c when the supply / demand plan is adopted. The display control unit 22d controls the display unit 24 according to the calculation result of the supply and demand plan.

  The storage unit 23 includes a hard disk device or a flash memory. The storage unit 23 includes a problem storage unit 23a, a parameter storage unit 23b, and a supply and demand plan storage unit 23c. The problem storage unit 23a stores an optimization problem solved by the supply and demand plan calculation unit 22b. The parameter storage unit 23b stores parameters acquired by the supply and demand plan calculation unit 22b. The supply and demand plan storage unit 23c stores the supply and demand plan calculated by the supply and demand plan calculation unit 22b.

  The display unit 24 is a display, for example, and displays parameters, supply and demand plans, and the like. The display unit 24 may display detailed information included in parameters, supply and demand plans, and the like. For example, the display unit 24 includes a touch panel or the like, and may display an operation schedule (such as a charge / discharge schedule or a power generation schedule) of the power device when the power device in the microgrid G is selected. The display unit 24 may be controlled by the calculation unit 22 to display a predetermined message (for example, a guidance message or a warning message) to the user of the EMS 20.

  With reference to FIG. 3, the process performed in EMS20, ie, the power supply and demand plan optimization method of this embodiment, is demonstrated. The following processing is periodically executed while the EMS 20 is activated. As shown in FIG. 3, the overall control unit 20a sequentially determines whether or not it is a supply and demand plan calculation time (step S01). The frequency with which the supply and demand plan is calculated by the overall control unit 20a can be set at intervals of 30 minutes, for example. If it is determined in step S01 that it is the supply and demand plan time, the overall control unit 20a gives a demand and supply plan optimization calculation command to the supply and demand plan calculation unit 22b. In response to the instruction, the supply and demand plan calculation unit 22b calculates the supply and demand plan by solving the optimization problem (step S02). On the other hand, if it is determined in step S01 that it is not the planned supply and demand time, the overall control unit 20a repeats the determination in step S01.

  In the supply and demand plan optimization in step S02, the supply and demand plan calculation unit 22b specifically solves the supply and demand plan optimization problem and acquires some solution. Details of this step will be described later.

  When calculating the supply and demand plan, the supply and demand plan may be calculated considering only the supply and demand plan on a specific day. For example, a plan of 0:00 to 24:00 may be calculated at the time of the first supply and demand plan calculation, and a plan of 0:30 minutes to 24:00 may be calculated the next time. Further, a supply and demand plan for 24 hours ahead may be calculated without considering the date. For example, a plan from 0:00 to 24:00 may be calculated at the time of the first supply and demand plan calculation, and a plan from 0:30 minutes to the next 0:30 may be calculated the next time (see FIG. 5).

The supply / demand plan acceptance / rejection determination unit 22c determines whether to adopt the optimum solution obtained by the supply / demand plan calculation unit 22b, that is, the supply / demand plan (step S03). In step S03, the supply and demand plan acceptance / rejection determination unit 22c examines the supply and demand plan calculated in step S02, and stores it in the supply and demand plan storage unit 23c when adopting it as a supply and demand plan. If an executable solution is obtained in step S02, the supply / demand plan acceptance / rejection determination unit 22c unconditionally saves the solution in the supply / demand plan storage unit 23c and updates the supply / demand plan (step S04).
Even if an infeasible solution is obtained in step S02, if the cause is that the future constraint cannot be satisfied, the supply / demand plan adoption determination unit 22c is provided on the condition that all the constraints on the current time are satisfied. The solution is provisionally adopted as a supply and demand plan (step S05). The display control unit 22d displays a warning message on the display unit 24 (step S06). The supply / demand plan acceptance / rejection determination unit 22c stores the solution in the supply / demand plan storage unit 23c, and updates the supply / demand plan (step S04).

  Examples of such a case include a shortage of storage battery SOC (state of charge) at peak demand. Even in such a case, the feasible solution may be obtained in the future due to an increase in the amount of power generated by the renewable energy generator 5 due to changes in the weather. It is not necessary to end the processing of FIG. 3 at a stage. In step S06, the warning message displayed on the display unit 24 includes, for example, “There is a possibility that SOC will be insufficient in the future in the current prediction” according to the content of the constraint violation. If the supply and demand plan calculated in step S02 cannot be executed at the current time (step S05; NO), the supply and demand plan acceptance / rejection determination unit 22c rejects the solution and ends the process shown in FIG. To do.

  The EMS 20 is characterized by the supply and demand plan optimization process in step S02. With reference to FIG. 4, the supply-and-demand plan optimization process of step S02 is demonstrated. First, the initial value generation unit 22a determines whether or not the calculated optimal solution component is stored in the supply and demand plan storage unit 23c with respect to the independent variable at the first time (step S11) of the planned supply and demand plan. (Step S12). Here, the planned period means a certain period from the time of calculation by the EMS 20, for example, one day. When there is an optimal solution component that has been calculated for the independent variable at the time, the initial value generation unit 22a generates an initial value component of the independent variable at the time based on the existing optimal solution component (step S13). When there is no calculated optimal solution component for the independent variable at the time, the initial value generation unit 22a generates a specified initial value component (step S14). Note that when simply referred to as “optimal solution” or “initial value”, it means a vector including independent variable values at all times in the planning period. On the other hand, the term “optimal solution component” or “initial value component” means a part of a vector (for example, an independent variable corresponding to a control value related to a certain time).

  Here, the calculated (existing) optimum solution in step S13 is the optimum solution stored in the supply-demand plan storage unit 23c as a result of the supply-demand plan calculation performed by the supply-demand plan calculation unit 22b before the previous time. . That is, the initial value generation unit 22a obtains the optimum solution component at the time (first time of the plan period of the supply / demand plan) obtained before the calculation by the supply / demand plan calculation unit 22b from the supply / demand plan storage unit 23c. And the initial value of the independent variable at that time. Further, the prescribed initial value in step S14 can be set to 0 (zero) when the independent variable is the generated power of the prime mover 7, for example. When the independent variable is the charge / discharge power of the electric vehicle 8 or the storage battery 9, the current value of the charge / discharge power of the electric vehicle 8 or the storage battery 9 can be used.

  The overall control unit 20a gives a command to the initial value generation unit 22a, and repeats the processes of steps S12 to S14 in the initial value generation unit 22a for the independent variable at each time increased by unit time (for example, 1 hour or 30 minutes). Make it. When the initial value generation unit 22a performs the processing of steps S12 to S14 for the independent variable at the last time in the planning period of the supply and demand plan, the overall control unit 20a gives a command to the initial value generation unit 22a, and steps S12 to S14. End the process. In other words, the overall control unit 20a causes the initial value generation unit 22a to perform loop processing as many times as the number of time points during the planning period.

  When initial values are generated for the independent variables at all times within the planning period through the above processing, the demand-and-supply plan calculation unit 22b performs optimization calculation based on these initial values (step S16). Then, the supply / demand plan calculation unit 22b outputs the obtained optimal solution to the supply / demand plan adoption determination unit 22c (step S17).

  With reference to FIG. 5, the initial value in the calculation process of the supply and demand plan repeatedly implemented is demonstrated. As shown in FIG. 5, for example, at the time of initial supply and demand plan calculation (that is, at time 0:00), the calculated optimal solution is calculated for all times within the period of 0:00 to 24:00. Suppose that does not exist. In this case, the initial value generation unit 22a generates (sets) an appropriate search initial value. For example, as described above, when the independent variable is the generated power of the prime mover 7, it can be set to 0 (zero). When the independent variable is the charge / discharge power of the electric vehicle 8 or the storage battery 9, the current value of the charge / discharge power of the electric vehicle 8 or the storage battery 9 can be used.

  When the overall control unit 20a next calculates the supply and demand plan (for example, at 0:30 after 30 minutes), the optimal value obtained at the time of calculation of 0:00 is in the range of 0:30 to 24:00. A solution component exists and is stored in the supply and demand plan storage unit 23c. In this case, the initial value generation unit 22a uses, as initial value components, the optimum solution components at the corresponding corresponding times for the respective times within the range of 0:30 to 24:00 (each corresponding to a specific time). Generate (set). However, since there is no calculated optimal solution component in the range from 0:30 to 0:30, the initial value generation unit 22a generates (sets) an appropriate search initial value.

  In the example shown in FIG. 5, the calculated optimal solution component does not exist at the last time corresponding to the time interval (30 minutes in the above case) in which the calculation is repeated in the planning period. At the time excluding the last time (that is, the time overlapped with the previous calculation plan period), the initial value generation unit 22a sets the optimum solution component obtained at the previous calculation as the initial value component.

As described above, the supply and demand plan calculation unit 22b of the EMS 20 updates the optimal solution of the supply and demand plan by repeatedly solving the optimization problem at intervals shorter than the plan period. In this way, an attempt is made to express the demand-and-supply plan calculated sequentially by a mathematical formula. In the following description, the symbol t is the actual time (for example, 0:00 to 23:00) when the optimization calculation is executed. Symbol T is a planning period. A vector x (t) is a supply and demand plan at a stage of a certain real time t, and its components x ^t (t),... X ^{t + T} (t) are control values corresponding to the superscript planned time. is there. As the control value, for example, there are items as listed in Table 1 above. Although there may be a plurality of types of control values corresponding to each planned time, in the following, for the sake of simplicity, a mathematical expression is described assuming that only one type of control device (for example, a storage battery) exists. A symbol A (x _init , t) is an algorithm that returns an optimal solution x _opt with an initial value x _init as an argument. This algorithm A itself also depends on the time t due to, for example, a change in the predicted power generation amount. Change. There is no particular limitation on the algorithm used in this embodiment.

また、実時刻ｔに計算する、時刻ｔからｔ＋Ｔまでの需給計画最適解は、下記式（２）で表される。

Here, the initial supply and demand plan value calculated from the time t to t + T, which is calculated at the actual time t, is expressed by the following equation (1).

Further, the optimum supply and demand plan solution from time t to t + T calculated at the actual time t is expressed by the following equation (2).

First, at the time of the first supply-demand plan calculation (t = 0), the initial value x _init is expressed by the following equation (3), and the optimal solution x _opt is expressed by the following equation (4).

Next, in the next and subsequent supply-demand plan calculations, the initial value x _init is expressed by the following equation (5), and the optimal solution x _opt is expressed by the following equation (6).

In the above equation (5), since there is an optimum solution component calculated at the previous time t−1 up to time t + T−1, the value is set as an initial value. At time t + T, since there is no already obtained optimum solution component, an appropriate value is set as an initial value. In equation (5), 0 (zero) is set as an appropriate value. In addition to this, for example, an initial value for the previous time t + T + 1 is taken over, or an initial value for the time at the previous N point is set. For example, a value may be set by extrapolating the curve by fitting the value by the least square method or the like. Figure 6 is an initial value _{x init} and the optimal solution _{x opt,} and the initial value _{x init} in the next time t + 1 is shown at time t. In FIG. 6, the initial value is indicated by a chain line, and the optimum solution is indicated by a solid line.

  According to the EMS 20 and the power supply / demand plan optimization method described above, the optimization problem of the objective function, which is an optimization index, is solved by the supply / demand plan adoption determination unit 22c. The supply and demand plan calculation unit 22b obtains an optimal solution for the supply and demand plan including control values for the devices at a plurality of times within a plan period that is a fixed period from the time of calculation. Further, an initial value for search is generated by the initial value generation unit 22a. Here, the initial value generation unit 22a generates an initial value of the search based on the optimal solution obtained before the calculation by the supply and demand plan calculation unit 22b. The time change of the parameter (for example, the predicted value of the power generation amount by the prime mover 7) affecting the supply and demand plan of the microgrid G is basically gentle. Therefore, the time change of the component of the optimal solution corresponding to each time within the planning period is also gradual. For this reason, even when time passes and optimization calculation is performed again, the component corresponding to each time within the planning period of the obtained optimum solution is considered to be close to the optimum solution component of the already obtained optimum solution. . Therefore, even when performing so-called iterative calculations by generating the initial value of the search in the vicinity of the optimal solution of the new optimization problem based on at least one of the optimal solutions obtained before the calculation. The time to obtain the optimal solution can be shortened.

  In addition, an optimum solution component corresponding to a specific time within the planning period of an optimal solution obtained before the calculation by the supply and demand plan calculation unit 22b is searched for corresponding to the specific time of the new optimization problem planning period. By directly setting the initial value component, the initial value for searching for a new optimization problem can be set in the vicinity of the optimal solution and the calculation can be started, and the optimal solution can be obtained in a short time.

  In addition, when there is no optimal solution component obtained before the calculation time corresponding to a certain time, based on the optimal solution component corresponding to the time before the time obtained before the calculation time. The initial value component of the search corresponding to the time may be generated. For example, the optimal solution component corresponding to the time immediately before one point may be set to the initial value as it is. Alternatively, the optimal value components corresponding to the time of the previous N points may be curve-fitted using a least square method or the like and extrapolated to set the initial value components. In the microgrid, since the transition of the control value of the device (which is an independent variable in the optimization problem) is not random and is considered to have a certain degree of smoothness, it can be optimized by using the above method. A reasonable estimate of the solution component (value set as the initial value) is obtained. Therefore, it is possible to rationally set the initial value component at the time using the above concept even for a time when there is no already obtained optimal solution component within the planning period, and to obtain the optimal solution in a short time as described above. Can do.

  Subsequently, a power supply and demand plan optimization program for causing the EMS 20 to execute the series of processes described above will be described. As shown in FIG. 7, the power supply and demand plan optimization program 120 is inserted into a computer and accessed. Alternatively, the power supply and demand plan optimization program 120 is stored in the program storage area 110 formed in the storage medium 100 provided in the computer.

  The power supply / demand plan optimization program 120 includes an initial value generation module 121, a supply / demand plan calculation module 122, a supply / demand plan acceptance / rejection determination module 123, and a display control module 124. The functions realized by executing the initial value generation module 121, the supply and demand plan calculation module 122, the supply and demand plan acceptance / rejection determination module 123, and the display control module 124 include the above-described initial value generation unit 22a of the EMS 20 and the supply and demand. The functions of the plan calculation unit 22b, the supply and demand plan acceptance / rejection determination unit 22c, and the display control unit 22d are the same.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. For example, regardless of the presence or absence of an already obtained optimal solution obtained for the calculation target time, the control value obtained by adding a parameter change amount to the control value obtained one unit time ago is the initial value of the search in the optimization calculation. It may be an ingredient. For example, the predicted power generation amount of the solar power generator 3 can be used as a parameter. As an example, it is assumed that the predicted power generation amount of the solar power generator 3 corresponding to the time t is 10 kW at the previous calculation, but 6 kW at the current calculation. That is, the predicted power generation amount of the solar power generator 3 corresponding to the same time is reduced by 4 kW. In that case, with respect to the optimal solution component obtained at the time of the previous calculation (for example, the charge / discharge power of the storage battery 9 is 7 kW), taking into account the decrease in the predicted power generation amount of the solar power generator 3, The charge / discharge power 3 kW (= 7 kW-4 kW) of the storage battery 9 can be used as an initial value component at the time of the current calculation. In this way, even when the parameter fluctuates greatly, such as when the weather changes greatly, an initial value can be reasonably determined and an optimal solution can be obtained in a short time.

  In the above embodiment, the case where the EMS 20 is provided separately from the microgrid G has been described, but the grid control device 10 of the microgrid G may have the same function as the EMS20. The microgrid G may include a fuel cell system, for example.

DESCRIPTION OF SYMBOLS 1 Power supply system 2 External power system 3 Solar power generator 4 Wind power generator 5 Renewable energy generator 6 Load 7 Engine 8 Electric vehicle 9 Storage battery 20 Energy management system 20a General control part 22 Calculation part 22a Initial value generation part 22b Supply and demand Plan calculation unit 22c Supply / demand plan acceptance / rejection determination unit 23a Problem storage unit 23b Parameter storage unit 23c Supply / demand plan storage unit G Microgrid

Claims (6)

An energy management system for optimizing energy supply and demand plans in a microgrid that includes a power-controllable device including a power storage device, a generator that generates power using renewable energy, and a load, and that is connected to an external power system ,
Supply and demand planning that obtains an optimal solution of the supply and demand plan including control values for the equipment at a plurality of times within a planning period that is a fixed period from the time of calculation by solving an optimization problem of an objective function that is an optimization index A calculation unit;
An initial value generation unit that generates an initial value of a search when the optimization problem is solved in the supply and demand plan calculation unit,
The supply and demand plan calculation unit updates the optimal solution of the supply and demand plan by repeatedly solving the optimization problem at intervals shorter than the plan period,
The initial value generation unit obtains an initial value component of a search corresponding to at least one time within the planning period based on at least one of the optimal solutions obtained before the calculation by the supply and demand plan calculation unit. Generate energy management system.   The initial value generation unit searches for an optimal solution obtained before the time of calculation by the supply and demand plan calculation unit based on an optimal solution component corresponding to the specific time within the planning period and corresponding to the specific time The energy management system according to claim 1, wherein an initial value component is generated.   The initial value generation unit uses the optimal solution component corresponding to the specific time of the optimal solution obtained before the calculation by the supply and demand plan calculation unit as the initial value component of the search corresponding to the specific time. The energy management system according to claim 2.   The initial value generation unit determines whether or not there is an optimal solution component corresponding to each time in the planning period obtained before the calculation by the supply and demand plan calculation unit, and determines that there is no optimal solution component The energy management system according to claim 1, wherein an initial value component corresponding to the time is generated based on an already obtained optimum solution component corresponding to one or more times before the time. Electric power supply and demand plan optimization method for optimizing energy supply and demand plan in a microgrid equipped with an output-controllable device including a power storage device, a generator that generates power by renewable energy, and a load, and connected to an external power system Because
An initial value generation step in which the energy management system generates an initial value for searching for an optimization problem of an objective function that is an optimization index;
The energy management system solves the optimization problem using the initial value generated in the initial value generation step, thereby obtaining control values for the device at a plurality of times within a planning period that is a fixed period from the time of calculation. A supply and demand plan calculation step for obtaining an optimal solution of the supply and demand plan including
The energy management system repeatedly performs the supply and demand plan calculation step at an interval shorter than the planning period,
In the initial value generation step, based on at least one of the optimum solutions obtained before the supply and demand plan calculation step following the initial value generation step, an initial search corresponding to at least one time within the planning period is performed. Electricity supply and demand plan optimization method that generates value components. Electricity supply and demand that optimizes energy supply and demand plans for the energy management system in a microgrid equipped with a power-controllable device including a power storage device, a generator that generates power using renewable energy, and a load, and connected to an external power system A plan optimization program,
The energy management system,
Supply and demand plan calculation that obtains an optimal solution of the supply and demand plan including control values for the equipment at a plurality of times within a planning period that is a fixed period from the time of calculation by solving an optimization problem of an objective function that is an optimization index A supply and demand plan calculation unit that updates the optimal solution of the supply and demand plan by repeatedly solving the optimization problem at intervals shorter than the planning period, and
An initial value generation unit that generates an initial value of a search when the optimization problem is solved in the supply / demand plan calculation unit, wherein at least one of the optimal solutions obtained before the calculation by the supply / demand plan calculation unit An initial value generating unit that generates an initial value component of a search corresponding to at least one time within the planning period,
Electricity supply and demand plan optimization program that makes it work.

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