JP2012068947A - System for performing arithmetic processing relating to distribution of resource and method for determining resource distribution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system for performing arithmetic processing relating to the distribution of resources and a method for determining resource distribution in a network including a node which generates a resource and a node which consumes the resource in which a power is generated, and consumed by a load in a typical manner.SOLUTION: The system includes: means for calculating the value of an objective function based on variables showing the scale of a resource generated in a first node and variables showing a transmission rate; means for updating variables showing the scale of the resource only by a value corresponding to a differential value to be obtained by partially differentiating the objective function by the variables showing the scale of the resource; means for updating the variables showing the transmission rate only by a value corresponding to a differential value to be obtained by partially differentiating the objective function by the variables showing the transmission rate; means for repeating the calculation of the value of the objective function based on the updated value; and means for outputting the scale of the resource and the transmission rate when the calculation processing of the objective function is converged.

Description

  The present invention relates to a system for performing arithmetic processing related to resource allocation in a network including nodes that generate resources and nodes that consume resources, and a method for determining resource allocation.

  Conventionally, a power network for supplying power and a communication network for exchanging voice / data have been laid and maintained independently of each other. At present, a technology called Green ICT (Information and Communications Technology) is attracting attention for the purpose of efficiently using energy.

  In Green ICT, it is planned to integrate an information communication network represented by the Internet and a power network (power network) mainly operated by a power company into a common network. In addition, green energy sources (renewable natural energy sources) such as solar power generation, wind power generation, and biomass power generation, and batteries (batteries) mounted on HVs (Hybrid Vehicles) and EVs (Electric Vehicles) It is planned to integrate distributed energy sources such as through a network.

  By integrating such energy sources, a stable supply / supply system can be constructed as a whole. Furthermore, it is possible to utilize surplus power that is widely dispersed even for urgent power demand due to seasonal fluctuations in power supply or sudden failures.

  Although not related to the above-mentioned Green ICT, Japanese Patent Application Laid-Open No. 10-276458 discloses a configuration for automatically switching to an alternative carrier network when a power supply abnormality occurs. By adopting a configuration that automatically switches, the user need not invest or intervene in an expensive backup power supply system.

JP-A-10-276458

  However, at present, the system as described above is still being planned or has just started research and development, and there are many problems to be developed. In other words, specific details such as dynamic scheduling of power demand and supply load distribution and ideal operation system design policy that should be in the future are still in the investigation and examination stage.

  The present invention has been made to solve the above-described problems, and its purpose is typically to generate nodes and resources that generate resources such as generating power and consuming the load. It is an object of the present invention to provide a system for performing arithmetic processing related to resource allocation and a method for determining resource allocation in a network including consuming nodes.

  According to one aspect of the present invention, there is provided a system that performs arithmetic processing related to resource allocation in a network including a first node that generates resources and a second node that consumes resources. The system includes means for maintaining an objective function. The objective function includes a first function that outputs a cost value required for the resource supplied from the first node, which monotonically increases with respect to the size of the resource, and a second of the resources generated at the first node. Transmission in the path of resources from the first node to the second node that outputs a larger value as the difference between the size of the resource supplied to the node and the size of the resource consumed by the second node increases. And a second function having the rate as a variable. The system further includes means for calculating a value of the objective function based on a variable indicating the size of the resource generated at the first node and a variable indicating the transmission rate, and the objective function indicates the size of the resource. A means for updating a variable indicating the size of a resource by a value corresponding to a differential value obtained by partial differentiation with a variable, and a value corresponding to a differential value obtained by partial differentiation of an objective function with a variable indicating a transmission rate. A means for updating the variable indicating the transmission rate, a means for repeatedly calculating the value of the objective function based on the updated value, and a resource size and a transmission rate when the objective function calculation process converges are output. Means.

  Preferably, the objective function further includes a third function that outputs a larger value as the size of the resource generated in the first node approaches zero.

  Preferably, the objective function further includes a fourth function that outputs a smaller value as the transmission rate approaches “0” or “1”.

  Preferably, both the variable indicating the size of the resource and the variable indicating the transmission rate are updated before the value of the objective function is newly calculated.

  Alternatively, preferably, before the value of the objective function is newly calculated, one of a variable indicating the size of the resource and a variable indicating the transmission rate is updated.

  Preferably, it is determined that the objective function calculation process has converged when the calculated value of the objective function substantially maintains the minimum value.

  Preferably, the network further includes a third node that relays resources or stores resources. The second function includes a function related to the size of the resource supplied from the first node to the third node, a function related to the size of the resource supplied from the first node to the second node, and a third And a function related to the size of the resource supplied from the first node to the second node.

  Preferably, the system further includes means for determining a characteristic function related to the time of the size of the resource consumed in the second node by acquiring and learning real information about the second node. The means for calculating the value of the objective function calculates the value of the objective function based on the future resource consumption determined by the characteristic function.

Preferably, the network is associated with a network that supplies power.
According to another aspect of the present invention, a method is provided for determining resource allocation in a network that includes a first node that generates resources and a second node that consumes resources. The method includes the step of the arithmetic processing unit holding an objective function. The objective function includes a first function that outputs a cost value required for the resource supplied from the first node, which monotonically increases with respect to the size of the resource, and a second of the resources generated at the first node. Transmission in the path of resources from the first node to the second node that outputs a larger value as the difference between the size of the resource supplied to the node and the size of the resource consumed by the second node increases. And a second function having the rate as a variable. The method further includes a step in which the arithmetic processing unit calculates a value of an objective function based on a variable indicating the size of the resource generated in the first node and a variable indicating the transmission rate; A step of updating a variable indicating the size of a resource by a value corresponding to a differential value obtained by partial differentiation with a variable indicating the size of the differential value obtained by partial differentiation of an objective function with a variable indicating a transmission rate The size of the resource when the variable indicating the transmission rate according to the value is updated, the step of repeating the calculation of the value of the objective function based on the updated value, and the calculation processing of the objective function converge And a step of outputting a transmission rate.

  According to the present invention, resources can be appropriately distributed in a network including nodes that generate resources and nodes that consume resources.

It is a schematic diagram which shows the structure of the electric power supply and demand control system according to this Embodiment. It is a block diagram which shows the hardware constitutions of the controller which concerns on this Embodiment. It is a figure showing typically an example of development of an existing electric power network. It is a figure which shows the typical model in the existing electric power system. It is a figure which shows an example of the constraint function _Hp ^{* according to} embodiment of this invention. It is a diagram illustrating an example of a constraint function H _B and constraint function H _Q according to an embodiment of the present invention. Is a diagram showing an example of an embodiment according to the constraint function H _{e (W i)} of the present invention. Is a diagram illustrating an example of a constraint function H _s according to the embodiment of the present invention. It is a flowchart which shows the control procedure about the existing electric power system according to embodiment of this invention. It is a figure showing typically an example of a microgrid. It is a flowchart which shows the control procedure about the existing microgrid according to embodiment of this invention. Is a graph showing temporal changes of the supply power P _i from power plants nodes observed by simulations for existing power network. It is a graph which shows the time change of the power transmission efficiency _wij observed by the simulation about the existing electric power network. It is a graph which shows the time change of the objective function R observed by the simulation about the existing electric power network. Is a graph showing temporal changes of the supply power P _i from power plants nodes observed by simulation for microgrid. Is a graph showing temporal changes in demand node Q _k observed by simulation for microgrid. It is a graph which shows the time change of the power transmission efficiency wij observed by the simulation about a microgrid. It is a graph which shows the time change of the objective function R observed by the simulation about a microgrid. Is a graph showing temporal changes in demand node Q _k observed by accident simulation for microgrid. Is a graph showing temporal changes of the supply power P _i from power plants nodes observed by accident simulation for microgrid. It is a graph which shows the time change of the electric power transmission efficiency _wij observed by the accident simulation about a microgrid. It is a graph which shows the time change of the objective function R observed by the accident simulation about a microgrid. It is a figure which shows typically about the structural example by which the several microgrid was integrated with the existing electric power network. Is a graph showing temporal changes of the supply power P _i from power plants nodes observed by simulation for Smart Grid (Node 1) (for synchronous mode). Is a graph showing the time variation of power B _j supplied to the capacitor observed by simulation for smart grid (node 17) (in synchronous mode). It is a graph which shows the time change of the power transmission efficiency _wij observed by the simulation about a smart grid (in the case of synchronous mode). It is a graph which shows the time change of the objective function R observed by the simulation about a smart grid (in the case of synchronous mode). Is a graph showing temporal changes of the supply power P _i from power plants nodes observed by simulation for Smart Grid (Node 1) (for asynchronous mode). Is a graph showing the time variation of power B _j supplied to the capacitor observed by simulation for smart grid (node 17) (for asynchronous mode). It is a graph which shows the time change of the power transmission efficiency wij observed by the simulation about a smart grid (in the case of asynchronous mode). It is a graph which shows the time change of the objective function R observed by the simulation about a smart grid (in the case of asynchronous mode). It is a figure which shows typically the example of the network architecture which integrated the service layer for performing the demand prediction according to this Embodiment. It is a figure which shows typically the example of a network architecture at the time of mounting the system according to this Embodiment in a new generation network. It is a figure which shows typically the network structure for implement | achieving the prediction learning layer according to this Embodiment. It is a figure which shows typically the operation | movement in the algorithm learning according to this Embodiment. It is a figure which shows typically the example of mounting in the algorithm learning according to this Embodiment.

  Embodiments of the present invention will be described in detail with reference to the drawings. Note that the same or corresponding parts in the drawings are denoted by the same reference numerals and description thereof will not be repeated.

  In this embodiment, as a typical example of arithmetic processing related to resource allocation in a network including nodes that generate resources and nodes that consume resources, a network that supplies power (existing power network, microgrid, smart Grid). In other words, the resource corresponds to “power”, the node that generates the resource corresponds to an entity that generates power such as “power plant”, and the node that consumes the resource consumes power such as “load” and “demand” It corresponds to the subject to do. Then, according to the situation in the network that supplies power, determination is made such as distribution of generated power and distribution of consumed power.

  The present invention can be used for various applications as long as it is not only a network that supplies power but also a network in which resources are generated, transmitted, and disappear in the network.

  For example, as described later, when natural products, general merchandise, rare metals, etc. scattered on the earth are regarded as “nodes that generate resources (resources)”, consumers who consume these resources are “ It can be regarded as a “resource consuming node”. The present invention can be applied to an optimal prediction distribution network / service system for demand / supply and a distribution system for these resources.

<A. System configuration>
First, the system configuration of the power supply / demand control system according to the present embodiment will be described.

  FIG. 1 is a schematic diagram showing a configuration of a power supply / demand control system according to the present embodiment. Referring to FIG. 1, the system includes a power plant, a substation / distribution station, a capacitor, a demand, and the like constituting the power system. The controller 100 obtains a state value in each of these elements and calculates a control value for each element by executing a control logic as will be described later.

  More specifically, the present system includes a controller 100 and field controllers 10, 20, and 30.

  The field controller 10 is disposed in the power plant, collects state values (operating state, generated power, etc.) in the power plant, and controls the power plant in accordance with a control command from the controller 100. More specifically, the field controller 10 includes a network I / F 11 for communicating with the controller 100 through the network 42, a sensor 12 for obtaining a state value, and an actuator 13 for actually controlling each device. Including.

  Similarly, the field controller 20 is arranged in the substation / distribution station, collects state values (transmission power, transmission rate, etc.) in the substation / distribution station, and in accordance with a control command from the controller 100, the substation / distribution station. To control. Similar to the field controller 10, the field controller 20 includes a network I / F 21, a sensor 22, and an actuator 23.

  Further, the field controller 30 is arranged in a consumer such as a factory or a home, collects state values such as a condenser and a load provided in the consumer, and controls the condenser in accordance with a control command from the controller 100. In addition, when the photovoltaic power generation equipment etc. are provided in the consumer, these information is also collected. Similarly to the field controller 10, the field controller 30 includes a network I / F 31, a sensor 32, and an actuator 33.

<B. Hardware configuration>
Next, the hardware configuration of controller 100 according to the present embodiment will be described with reference to FIG. FIG. 2 is a block diagram showing a hardware configuration of the controller 100 according to the present embodiment.

  The controller 100 includes a computer main body 102, a monitor 104 as a display device, and a keyboard 110 and a mouse 112 as input devices. The monitor 104, keyboard 110, and mouse 112 are connected to the computer main body 102 via the bus 105.

  The computer main body 102 includes a flexible disk (hereinafter also referred to as “FD”) drive 106, an optical disk drive 108, a CPU (Central Processing Unit) 120, a memory 122, and a direct access memory device such as a hard disk 124. A communication interface 128. These components are connected to each other by a bus 105.

  The FD drive 106 reads and writes information from and to the FD 116. The optical disk drive 108 reads information on an optical disk such as a CD-ROM (Compact Disk Read-Only Memory) 118. The communication interface 128 exchanges data with the outside.

  The CD-ROM 118 may be another medium, such as a DVD-ROM (Digital Versatile Disk) or a memory card, as long as it can record information such as a program installed in the computer main body. In this case, the computer main body 102 is provided with a drive device that can read these media. The bus 105 may be connected to a magnetic tape device that is detachably loaded with a cassette type magnetic tape.

  The memory 122 includes a ROM (Read Only Memory) and a RAM (Random Access Memory).

  The hard disk 124 stores a program and various setting values for realizing a power supply / supply load control logic according to the present embodiment to be described later. More specifically, the hard disk 124 includes an objective function generation module 131, an objective function calculation module 132, a variable update module 133, a convergence determination module 134, and a parameter file 135.

  The CPU 120 executes the objective function generation module 131 to generate an objective function (data indicating) used for optimizing the resource allocation in the target network, and the generated objective function is stored in the memory 122 or the like. Hold. Details of the objective function will be described later.

  When the CPU 120 executes the objective function calculation module 132, the value is calculated based on the held objective function. The calculation of the value of the objective function is based on a variable indicating the size of the resource (power) generated at the node that generates the resource (typically a power plant) and a variable indicating the transmission rate between the nodes. Based on.

  When the CPU 120 executes the variable update module 133, the parameter used for calculating the value of the objective function is updated. More specifically, the CPU 120 updates the variable indicating the resource size by a value corresponding to the differential value obtained by partial differentiation of the objective function with the variable indicating the resource size. Further, the CPU 120 updates the variable indicating the transmission rate by a value corresponding to the differential value obtained by partial differentiation of the objective function with the variable indicating the transmission rate.

  When the CPU 120 executes the convergence module determination 134, the calculation of the objective function is repeatedly executed based on the parameter value updated by the execution of the variable update module 133, and the calculation process of the objective function has converged. Determine whether or not. The CPU 120 outputs the resource size and the transmission rate when the objective function calculation process converges.

  The parameter file 135 holds various settings regarding the topology of the target network and members constituting the network.

  The CPU 120 functioning as an arithmetic processing unit executes processing corresponding to each program described above using the memory 122 as a working memory.

  The computer hardware itself shown in FIG. 2 and its operating principle are general. Therefore, an essential part for realizing the functions of the present invention is software stored in a storage medium such as the FD 116, the CD-ROM 118, and the hard disk 124.

<C. Electricity demand / supply load control logic>
(C1: Development of existing power network)
FIG. 3 is a diagram schematically illustrating a development example of an existing power network. For reference to FIG. 3, reference was made to Goda et al., “Microgrid for coexistence of distributed power supply and power network”, Denki Shimbun Books-Energy Shinsho, page 29, 2004.

  First, a configuration example in which an existing power network is integrated with a microgrid (hereinafter also referred to as “MG”) will be described with reference to FIG. 3.

  As shown in FIG. 3 (a), in an existing power network, a plurality of power plants (a power plant and a generator) are connected in parallel, and the plurality of power plants provide power to consumers (loads). Supply. When a plurality of MGs are coupled to the existing power network shown in FIG. 3A, the configuration is as shown in FIG.

  Each of the MGs typically includes a power / heat supply facility (not shown in FIG. 3B), a power storage facility, a power network, and a control device using information communication technology (FIG. 3B). (Not shown) and elements such as a plurality of loads. MG differs greatly from existing power networks (so-called commercial power systems) in that it uses heat and uses power storage equipment.

  A plurality of such MGs are combined to form a so-called smart grid.

(C2: Modeling of micro grid / smart grid)
Next, a method of modeling each component in order to realize control of power demand / supply load in the microgrid and smart grid will be described below.

  FIG. 4 is a diagram illustrating a typical model in an existing power system. In the existing power system shown in FIG. 4, three elements of a power plant (P), a substation / distribution station (T), and a demand (Q) are hierarchically coupled. Hereinafter, these elements are referred to as “nodes”.

More specifically, a power transmission line w _{ij for} transmitting power is coupled to the power plant node P _i , and similarly, power is transmitted to the substation / distribution station node B _{j. Are} connected to each other.

On the other hand, in the microgrid shown in FIG. 3, the power from one power plant node P _i is supplied to a plurality of capacitor nodes B _j and demand nodes Q _k through power transmission paths w _ij and w _ik , respectively. Supplied. Although not shown in FIG. 3, each power network cable is provided with a mechanism for acquiring necessary information via a middleware layer described later.

(C3: Model formula for existing power system)
Referring again to FIG. 4, the electric power supplied from the i-th power plants nodes P _i and P _i, the power delivered from the j-th substation / power distribution station Node B _j and B _j, k-th demand the power supplied to the node Q _k and Q _k, the power transmission efficiency from the i-th power plant node to j-th substation / power distribution station node and w _ij, k-th from the j-th substation / power distribution station nodes If the power transmission efficiency to the demand node is w _jk , Equations (1) and (2) are established between these physical quantities. In the following description, the same code “P _i ” is shared as a code indicating “i-th power plant node” and a code indicating “power supplied from the i-th power plant node”. The same applies to other cases.

  Furthermore, the objective function R for evaluating the power balance of the entire power system can be defined as in equation (3).

  In the above equation, λ, μ, ν, and ξ are constants that define the penalty weight of each constraint function, and are all set to constant values.

The objective function R in the equation (3) will be described in more detail. P _{0 in} the first term on the right side of the equation (3) is a function indicating a cost necessary for generating power at the power plant node. In addition, H _p ^{* in} the second term on the right side of the equation (3) is a constraint function that constrains the power at each power node so that it does not become zero. Further, H _v ^{* in} the third term on the right side of the equation (3) is a constraint function for defining the minimum power and the maximum power of each power node. H _e ^{* in} the fourth term on the right side of the equation (3) is a constraint function for making the power supplied from each power node as the supply source equal to the total of the power (demand) of the supply destination. H _s ^{* in} the fourth term on the right side of equation (3) is a constraint function related to a switch that switches between supplying and not supplying power.

In the control logic according to the present embodiment, the electric power supplied from the power plant node P _{i is changed} to P _i , and the transmission rate between the nodes is sequentially updated to search for a parameter having the minimum value of the objective function R. And based on this search result, the electric power flow in an electric power network is controlled, ie, distribution of electric power is controlled. As a mathematical method for minimizing the value of the objective function R will be described later, each constraint function included in the objective function R will be described first.

(A) Function P _{0 The} function P ₀ can be defined as the sum of fuel costs in the power plant included in the power system. The fuel cost of each power plant can be approximated as a quadratic expression with the supplied power P _i from the power plant as a variable. Specifically, it can be shown as follows using constants a _i , b _i , and c _i .

This function P ₀ is set so that its value decreases as the fuel cost decreases. That is, the function P ₀ is a function that monotonously increases with respect to the magnitude of the power that is a resource, and outputs a cost value required for the resource (power) supplied from the power plant node.

(B) Constraining function H _p ^{* The} constraint function H _p ^* is for constraining the power at each power node so that it does not become zero. Therefore, the value increases as the corresponding supply power P _i increases. A function that decreases is used. FIG. 5 shows an example of the constraint function H _p ^{* according to} the embodiment of the present invention. In the present embodiment, as shown in FIG. 5, for each power node, used is a value obtained power to supply power P _i of the constant-.alpha. _p, as a constraint function H _p ^*, these The sum of the values obtained for each power node is adopted.

That is, the constraint function H _p ^* used in the present embodiment can be expressed as follows.

This constraint function H _p ^* outputs a larger value as the magnitude of power (resource) generated at the power plant node approaches zero.

(C) Constraint function H _v ^{* The} constraint function H _v ^* is a constraint function for defining the minimum power and the maximum power of each power node. More specifically, it is necessary to consider the supply capacity at the substation / distribution node and the magnitude of the load at the demand node.

The constraint function H _v ^* used in the present embodiment can be expressed as follows.

Here, the constraint function H _v ^* includes a constraint function H _B and a constraint function H _Q. As the constraint function H _v ^* , the total sum of the values of the constraint function H _B and the constraint function H _Q obtained for each of these power nodes is adopted.

The constraint function H _B is a constraint that the power B _j of the substation / distribution node satisfies the limit values (maximum allowable power B _j ^max and minimum allowable power B _j ^min ) that can be transmitted. Further, the constraint function H _Q is a constraint that the demand Q _{k of the} demand node satisfies the load limit values (maximum allowable power Q _k ^max and demand power D _k ).

As the constraint function H _B and the constraint function H _Q , well-type functions are used in which the values become smaller as the center value of the limit range is closer. FIG. 6 shows an example of constraint function H _B and constraint function H _{Q according to} the embodiment of the present invention.

(D) Constraint Function H _e ^{* The} constraint function H _e ^* is a constraint function for making the supply power P _i supplied from each power node as the supply source equal to the total of the power (demand) of the supply destination. .

The constraint function H _e ^* used in the present embodiment can be expressed as follows.

Here, the constraint function H _e ^* includes a constraint function H _e (W _i ) and a constraint function H _Q (W _j ). More specifically, the constraint function H _e (W _i ) is used to satisfy the condition that the entire flow of supply power P _i generated by the power plant node P _i is limited by the total power. . The constraint function H _Q (W _i ) is used to satisfy the condition that the entire power flow transmitted by the substation / distribution station node B _j is limited by the total power.

As the constraint function H _e (W _i ) and the constraint function H _Q (W _j ), functions whose values are smaller as they are closer to the center value of the limit range are used. FIG. 7 is a diagram showing an example of the constraint function H _e (W _i ) according to the embodiment of the present invention.

Regarding variable W _i and variable W _j , power transmission efficiency w _ij from i-th power plant node to j-th substation / distribution node, and j-th substation / distribution node, respectively. Using the power transmission efficiency w _jk to the kth demand node, the following relationship is established.

This constraint function H _e ^* has a transmission rate (power transmission efficiency w _ij and w _jk ) in a power (resource) path from the power plant node to the demand node as a variable. The constraint function H _e ^* is larger as the difference between the magnitude of power supplied to the demand node and the magnitude of power consumed at the demand node among the power (resources) generated at the power plant node increases. Is output.

(E) Constraint function H _s ^{* The} constraint function H _s ^* is a constraint function related to a switch for switching between supplying and not supplying power. Specifically, power transmission efficiency between adjacent nodes (coefficient between power flow nodes × transmission rate between nodes) is considered. In the power flow, the transmission rate between nodes normally takes a value close to “0” or “1”.

The constraint function H _s ^* used in the present embodiment can be expressed as follows.

Here, c _ij represents a coefficient of power flow from node i to node j, and x _ij represents a transmission rate from node i to node j.

The constraint function H _s ^* outputs a smaller value as the transmission rate between the nodes is closer to “0” or “1”. FIG. 8 is a diagram showing an example of the constraint function H _{s according to} the embodiment of the present invention.

(C4: Solution of constraint function for existing power system)
In the present embodiment, as a method of searching for the minimum value of the objective function R shown in the above equation (3), the supply power P _i from the i-th power plant node is changed by a minute change ΔP _i , and The transmission rates x _ij and x _jk between the nodes at each time point are also sequentially calculated by changing the minute changes Δx _ij and Δx _jk . Then, the minimum value (convergence value) is searched.

That is, P _i is updated by a value corresponding to a differential value obtained by partial differentiation of the objective function R with P _i which is a variable indicating the magnitude of power (resource), and the objective function R is set to x indicating the transmission rate. _The transmission rates x _ij and x _jk are updated by values corresponding to the differential values obtained by partial differentiation with _ij and x _jk , respectively. Then, the calculation of the value of the objective function R is repeated based on the updated parameters. Then, the supply power P _i and the variables x _ij and x _jk when the calculation process of the objective function R converges are output.

In addition, before the value of the objective function R is newly calculated, a processing form for updating both P _i that is a variable indicating the magnitude of power (resource), and x _ij and x _jk indicating the transmission rate. (Hereinafter also referred to as “synchronous update method”) may be employed. Alternatively, a processing mode in which only one of them is updated (hereinafter also referred to as “asynchronous update method”) can be adopted.

First, the minute change ΔP _i of the supplied power P _i from the i-th power plant node can be calculated according to the following equation (4).

Here, to avoid periodic divergence, the constant η _p is scaled using a first order approximation for the equation obtained by Taylor expansion of R with respect to P _i , as shown below.

The constant η _p is defined as a reduction rate that reduces the original value of R by (1−η _p ) times. This is equal to the value in the next step of the objective function R in the case of linear approximation. Therefore, the constant η _p can be expressed as the following equation (5).

The supplied power P _i is sequentially updated according to P _i (t + 1) = P _i (t) + ΔP _i (t). The variable t indicates the number of times of calculation (step) in the convergence calculation of the objective function R described later.

In the same manner as described above, the inter-node transmission rate x _jk between the node B _j and the node Q _k can be expressed as the following equation (6).

  Similar to equation (5) above, to avoid periodic divergence, the constant η is scaled using a first order approximation for R, as shown in equation (7) below.

Next, the change Δx _{ij in} the transmission rate between the node P _i and the node B _j can be expressed as the following equation (8).

  Further, in order to avoid periodic divergence, the constant η is scaled according to the following equation (9), similarly to the above equation (7).

(C5: Control procedure for existing power system)
As a control procedure for the existing power system as shown in FIG. 3A, the calculation is repeated while the supplied power P _i from the power plant node, the transmission rate x _ij , and the transmission rate x _jk are synchronized and updated. Thus, each value at which the objective function R shown in the above equation (3) becomes the minimum value is sequentially determined.

  A specific processing procedure will be described with reference to FIG. FIG. 9 is a flowchart showing a control procedure for the existing power system according to the embodiment of the present invention.

Referring to FIG. 9, first, CPU 120 randomly determines initial values of transmission rates x _ij and x _jk (step S100).

The CPU 120 calculates the value of the objective function R using the above equation (3) during the period of forward power propagation (step S102). Then, the CPU 120 calculates the minute change Δx _jk for the transmission rate x _jk using the above-described equation (6) (step S104). Further, the CPU 120 calculates the minute change Δx _ij for the transmission rate x _ij using the above-described equation (8) (step S106). After that, the CPU 120 updates the transmission rates x _ij and x _jk according to the following formula (step S108).

x _jk (t + 1) = x _jk (t) + Δx _jk
x _ij (t + 1) = x _ij (t) + Δx _ij
In addition, the CPU 120 calculates a minute change ΔP _i for the supplied power P _i from the power plant node using the above-described equation (4) (step S110). Thereafter, CPU 120 may, according to the following formula, and updates the supply power _{P i} from the power plant node (step S112).

P _i (t + 1) = P _i (t) + ΔP _i
Furthermore, the CPU 120 determines whether or not the calculation for the objective function R has converged (step S114). More specifically, fine variation [Delta] P _i for supplying electric power _{P i} from the power plant node, small variation [Delta] x _jk for rate _{x jk,} none of the small change amount [Delta] x _ij for rate _{x ij} is stable In other words, if the amount of change is less than or equal to a predetermined threshold value, it is determined that it has converged. Otherwise, it is determined that it has not converged.

  That is, the CPU 120 determines that the calculation process of the objective function R has converged when the calculated value of the objective function R substantially maintains the minimum value.

If the calculation for the objective function R has not converged (NO in step S114), the processes in and after step S102 are repeated. On the other hand, if the calculation for the objective function R has converged (YES in step S114), the calculated supply power P _i from the power plant node, transmission rate x _ij , and transmission rate _jk are obtained. A control command is output to (step S116). That is, the power flow in the power network is controlled. Then, the process ends.

  Note that the processing procedure shown in the flowchart of FIG. 9 is executed every predetermined period or every event occurrence.

(C6: Model formula for microgrid)
The above model formula and its solution can be extended to the microgrid as described above.

  FIG. 10 is a diagram schematically illustrating an example of a microgrid. In the present embodiment, derivation of model formulas and execution results of various simulations are presented as an example when applied to the microgrid shown in FIG. 10, but this embodiment is not limited to generality. Can be applied to various microgrids.

As shown in FIG. 10, around the power plant node P _1, radially plural battery cells (battery) nodes and demand nodes and are coupled via a power network cable. In particular, in the microgrid shown in FIG. 10, the exchange of electric power between the capacitor nodes is also considered. This is because, when power is being supplied from one battery to deal with demand, when the power stored in the battery being supplied is about to be depleted, This is because a usage form such as accommodating the above is assumed. Or, there is a limit on the amount of power that can be stored in a capacitor, so when a certain capacitor cannot store any more power, it is also assumed that other capacitors store power Is done.

The power supplied from the i-th power plant node is P _i , the power supplied to the j-th battery node is B _j, and the power sent from the j′-th battery node to the j-th battery node is B _{j Suppose} that the power supplied to the kth demand node is Q _k, and the power transmission efficiency w between the nodes is used, the above equations (1) and (2) are expressed between these physical quantities. By expanding, equations (10) to (12) are established.

  Furthermore, the objective function R for evaluating the power balance of the entire power system can be defined as in equation (13).

In the above equation, λ, μ, ν, and ξ are all constants.
The meaning of each function (function P ₀ , constraint function H _p ^* , constraint function H _v ^* , constraint function H _e ^* , constraint function H _s ^* ) constituting the objective function R of the equation (13) is described above. It is the same as that. That is, the function P ₀ indicates the cost required to generate power at the power plant node, and the constraint function H _p ^* is the number of constraints that prevent the power at each power node from becoming zero. The constraint function H _v ^* defines the minimum power and the maximum power of each power node, and the constraint function H _e ^* indicates that the power supplied from each power node as the supply source The constraint function H _s ^* relates to a switch that switches between supplying and not supplying power.

In the microgrid shown in FIG. 10, the function P ₀ , the constraint function H _p ^* , the constraint function H _v ^* , the constraint function H _e ^* , and the constraint function H _s ^* can be defined as shown below. In the microgrid shown in FIG. 10, there are more nodes than in the existing power network shown in FIG. 4. Therefore, compared to the constraint function used in the modeling of the existing power network, It is a function that includes many variables.

Among these, the constraint function H _e ^* takes into account a substation / distribution node that relays power (resource) or a capacitor (battery) node that stores power (resource). That is, the constraint function H _e ^* relates to a function related to the size of the resource supplied from the power plant node P _i to the demand node Q _{k and} to the size of the resource supplied from the power plant node P _i to the capacitor node B _j . And a function related to the size of the resource supplied from the battery node B _j to the demand node Q _k .

(C7: Solution of constraint function for microgrid)
As a method of searching for the minimum value of the objective function R for the microgrid shown in the above equation (13), (1) a method of sequentially updating a plurality of variables (synchronous update method), and (2) A method of updating a plurality of variables at different timings (asynchronous update method) can be adopted.

As for the method (1), in the same way as the method for searching for the minimum value of the objective function R (Equation (3)) for the existing power system described above, the minute change ΔP for the supplied power P _i from the power plant node. _i , and small changes Δx _jk , Δx _ik , Δx _ij , Δx _{j′j for} each of the transmission rates x _jk , x _ik , x _ij , x _j′j , x _j′k , x _ij at each _node , Δx _j′k , Δx _ij are updated simultaneously in the same step. Then, the minimum value (convergence value) is searched.

  On the other hand, in the method (2), only a part of the parameters as described above is updated in each step.

Hereinafter, a mathematical calculation method for minute conversion will be described.
First, the minute change ΔP _i for the supplied power P _i from the power plant node can be calculated according to the following equation (14).

Next, the minute changes Δx _jk , Δx _ik , Δx _ij , Δx _j′j , Δx _j′k , Δx _{ij at} each node can be expressed as the following equations (15) to (20). it can.

In order to avoid periodic divergence, a constant η is introduced in the same manner as in the above formulas (5) and (7), and a minute change ΔP _i , for the supplied power P _i from the power plant node, It is preferable to scale the minute change Δx at each node.

(C8: Control procedure for microgrid)
A microgrid as shown in FIG. 10 will be described with reference to FIG. FIG. 11 is a flowchart showing a control procedure for an existing microgrid according to the embodiment of the present invention.

Referring to FIG. 10, first, CPU 120 determines whether or not any event has occurred in the target microgrid (step S200). This event means an event that restricts various parameters in the target microgrid. If any event has occurred (YES in step S200), CPU 120 determines target parameters (supply power P _i and transmission rates x _jk , x _ik , x _ij , x _j′j , x _{j ′). k,} is set to a value corresponding to any) events _{x ij} (step S202). Then, the process proceeds to step S204.

  On the other hand, if no event has occurred (NO in step S200), the process of step S202 is skipped.

In step S204, the CPU 120 determines the initial values of the transmission rates x _jk , x _ik , x _ij , x _j′j , x _j′k , and x _ij (except those set to predetermined values in step S202). Are determined at random (step S204).

The CPU 120 calculates the value of the objective function R using the above equation (13) during the period of forward power propagation (step S208). Then, the CPU 120 uses the above-described equations (15) to (20), and the minute change _amounts Δx _jk , Δx _ik , Δx _ij , Δx _j′j , Δx _j′k , Δx _ij (step S202). (Except those set to predetermined values in step S210) (step S210). Thereafter, the CPU 120 _updates the transmission rates x _jk , x _ik , x _ij , x _j′j , x _j′k , and x _ij (except for those set to predetermined values in step S202) according to the following formulas. (Step S210).

x _jk (t + 1) = x _jk (t) + Δx _jk
x _ik (t + 1) = x _ik (t) + Δx _ik
x _ij (t + 1) = x _ij (t) + Δx _ij
x _j′j (t + 1) = x _j′j (t) + Δx _j′j
x _j′k (t + 1) = x _j′k (t) + Δx _j′k
x _ij (t + 1) = x _ij (t) + Δx _ij
Further, the CPU 120 calculates the minute change ΔP _i for the supplied power P _i using the above-described equation (14) (step S212). Thereafter, CPU 120 may, according to the following formula, and updates the supply power _{P i} (step S214).

P _i (t + 1) = P _i (t) + ΔP _i
Further, the CPU 120 determines whether or not the calculation for the objective function R has converged (step S216). More specifically, the supply power _{P i} minimal change amount [Delta] P _i for, and, a minute change amount [Delta] x _jk for _{rate, Δx ik, Δx ij, Δx} j'j, Δx j'k, none of the [Delta] x _ij Is stable, that is, if the amount of change is less than or equal to a predetermined threshold value, it is determined that it has converged. Otherwise, it is determined that it has not converged.

If the calculation for the objective function R has not converged (NO in step S216), the processes in and after step S204 are repeated. On the other hand, when the calculation for the objective function R has converged (in the case of YES in step S216), the calculated supply power P _i and transmission rates _jk , x _ik , x _ij , x _j′j , x _A control command is output so as to be _j′k , x _ij (step S218). That is, the power flow in the power network is controlled.

  Note that the processing procedure shown in the flowchart of FIG. 11 is executed every predetermined period or every event occurrence.

<D. Simulation results>
Hereinafter, the result of the simulation using the objective function as described above will be shown.

(D1. Existing power network)
As conditions for the simulation, the constants λ, μ, ν, and ξ that define the weight of each constraint function (penalty) are all “1”. Also, the constants a _i , b _i , and c _i that define the fuel cost are all set to “1” from the viewpoint of simplifying the objective function.

For the power B _{j of} the substation / distribution node or capacitor node and the demand Q _k of the demand node, values normalized (0 ≦ B _j ≦ 1, 0 ≦ Q _k ≦ 1) were used. Then, the minimum allowable power B _j ^min = “0.2” and the maximum allowable power B _j ^max = “0.8”. Further, the demand power D _k = “0.2” and the maximum allowable power Q _k ^max = “0.8”.

As other parameters, a constant α _p = “0.5” defining the constraint function H _p ^* is set, and a constant α _B = α _Q defining the constraint function H _v ^* (the constraint function H _B and the constraint function H _Q ). = “4.0”, constant β _e = “0.05” defining the constraint function H _e ^* , and constant γ _e = “0.5”.

Furthermore, the constant η ₀ = “0.01” used for the first-order approximation for avoiding periodic divergence is set, and the coefficients c _ij , c _jk , c _ik , c _j′j , c of the power flow between the nodes are _set . _j′k and c _{ij ′} = “1.0”.

As a simulation target for an existing power network, there are two power plant nodes, three substation / distribution node, and five demand nodes. Supply power P _{i from} the power plant node, power transmission efficiency w _ij between the power plant node and the substation / distribution node, and power transmission efficiency w _jk between the substation / distribution node and the demand node Changes in the value of the objective function R were observed while changing the values synchronously.

Figure 12 is a graph showing temporal changes of the supply power P _i from power plants nodes observed by simulations for existing power network. FIG. 13 is a graph showing the time change of the power transmission efficiency w _ij observed by the simulation for the existing power network. FIG. 14 is a graph showing the time change of the objective function R observed by the simulation for the existing power network.

As shown in FIG. 12, the supplied power P _i is the simulation start after 100 steps (convergent calculation count: 100) from power plants nodes rapidly increasing, it can be seen that reaches "1.2". Further, as shown in FIG. 13, the power transmission efficiency w _ij between the power plant node and the substation / distribution node and the power transmission efficiency w _jk between the substation / distribution node and the demand node It can also be seen that convergence to a stable value is performed in 100 steps (convergence calculation count: 100) after the simulation is started.

  As a result, as shown in FIG. 14, the value of the objective function R also monotonously decreases, and it can be seen that a stable point of about “15” has been reached in 100 steps (convergence calculation number: 100) after the start of the simulation. .

  From the simulation results shown in FIGS. 12 to 14, it can be said that an appropriate solution in the existing power system can be determined in a short time by using the objective function according to the present embodiment.

(D2. Microgrid)
As conditions for the simulation, the same conditions as those for the above-described existing power network were adopted.

As a simulation target for the microgrid, there are one power plant node (supply power P _i ), four power storage nodes (power B _j ), and three demand nodes (demand Q _k ) as shown in FIG. The configuration. Supply power P _{i from} the power plant node, power transmission efficiency w _ij between the power plant node P _i and the battery node B _j , and power transmission efficiency w _jk between the battery node B _j and the demand node Q _k , The power transmission efficiency w _ik between the power plant node P _i and the demand node Q _k was changed synchronously, and the change in the value of the objective function R was observed.

Figure 15 is a graph showing temporal changes of the supply power P _i from power plants nodes observed by simulation for microgrid. Figure 16 is a graph showing temporal changes in demand node Q _k observed by simulation for microgrid. FIG. 17 is a graph showing the time change of the power transmission efficiency w _ij observed by the simulation of the microgrid. FIG. 18 is a graph showing the time change of the objective function R observed by the simulation of the microgrid.

As shown in FIG. 15, the supplied power _{P i} is 1800 steps (convergent calculation count: 1800) from power plants nodes rapidly increasing, it can be seen that reaches "2.2". Further, as shown in FIG. 16, increases monotonically values demand Q _k in demand node, it can be seen that reaches "0.35".

As shown in FIG. 17, even when 1% noise and 10% initial value are added, all the power transmission efficiencies w _ij , w _jk , w _ik between power nodes are all 0. It turns out that it has converged on the stable value in the range of 1-0.2. As shown in FIG. 18, it can be seen that the value of the objective function R also decreases smoothly and reaches a stable point of about “25”.

  From the simulation results shown in FIGS. 15 to 18, by using the objective function according to the present embodiment, an appropriate solution in the microgrid is determined in a short time and stably regardless of the initial value setting. Can be said.

(D3. Microgrid (when an accident occurs))
Next, in the simulation about the above-mentioned microgrid, the time change when an accident occurred was observed. More specifically, in step 2500, the power plant node P _i and the demand node Q _k are disconnected (power transmission efficiency w _ik = 0 (open)).

FIG. 19 is a graph showing the time change of the demand node Q _k observed by the accident simulation for the microgrid. Figure 20 is a graph showing temporal changes of the supply power P _i from power plants nodes observed by accident simulation for microgrid. FIG. 21 is a graph showing temporal changes in the power transmission efficiency w _ij observed by the accident simulation for the microgrid. FIG. 22 is a graph showing the time change of the objective function R observed by the accident simulation for the microgrid.

As shown in FIG. 19, since the power from the power plant node is not directly supplied to the demand node, the demand _Qk is instantaneously decreased at 2500 steps when the accident occurred. On the other hand, the supplied power P _i from the power plant node varies only slightly. This is because the generated power continues to be supplied to other demand nodes and capacitor nodes through the bypass path.

With the exception of the power transmission path w _ik set to “0”, the power supply is restored by detour transmission paths such as other power transmission paths w _ij , w _jk , and w _{ij ′} w _j′k . FIG. 21 shows a state in which the power transmission efficiency between the power plant node P _i and the demand node Q _k recovers with time through the bypass path. That is, even after the power transmission efficiency w _ik is reduced to “0” in 2500 steps, the power transmission efficiency w _ij and w _{jk of} other detour transmission paths increases to a positive value around the time point of 3600 steps. It can be seen that the power supply is restored.

  On the other hand, as shown in FIG. 22, even when such an accident occurs, it can be understood that the value of the objective function R slightly increases although it slightly increases.

(D4. Smart grid)
Next, the result of having performed the simulation about the smart grid integrated with the existing electric power network is shown.

  FIG. 23 is a diagram schematically illustrating a configuration example in which a plurality of microgrids are integrated into an existing power network. That is, the configuration example shown in FIG. 23 has two substation nodes located in the first layer (layer # 1) and three substations located in the third layer (layer # 3) with the power plant node as a vertex. Power network including nodes. This power network corresponds to an existing power system. Three microgrids (microgrids # 1, # 2, and # 3) are coupled to the existing power system. In FIG. 23, for convenience of explanation, each node is numbered.

  Also in the configuration shown in FIG. 23, the power transmission path w and the communication network (computer network) for realizing the power supply / demand control system are integrated through a middleware layer (details will be described later).

As conditions for the simulation, the constants λ, μ, and ν that define the weight of the penalty are all “1.4”, and the constant ξ is “1”. Also, the constants a _i , b _i , and c _i that define the fuel cost are all set to “1” from the viewpoint of simplifying the objective function.

For the power B _{j of} the substation / distribution node or capacitor node and the demand Q _k of the demand node, values normalized (0 ≦ B _j ≦ 1, 0 ≦ Q _k ≦ 1) were used. Then, the minimum allowable power B _j ^min = “0.2” and the maximum allowable power B _j ^max = “0.8”. Further, the demand power D _k = “0.2” and the maximum allowable power Q _k ^max = “0.8”.

As other parameters, a constant α _p = “0.22” that defines the constraint function H _p ^* is set, and a constant α _B = α _Q that defines the constraint function H _v ^* (the constraint function H _B and the constraint function H _Q ). = “4.0”, constant β _e defining constraint function H _e ^* = “0.05”, and constant γ _e = “0.5”, constant β _s defining constraint function H _s ^* = "0.15".

Furthermore, the constant η ₀ = “0.01” used for the first-order approximation for avoiding periodic divergence was set.

Similar to the above simulation, the supply power P _i from the power plant node (node 1) and the power transmission efficiency w between the nodes were changed synchronously, and the change in the value of the objective function R was observed. Furthermore, the behavior when an accident occurred was observed as in the above simulation. Specifically, in step 250 after the start of the simulation, the power distribution node P ′ _i and the capacitor node B _j are disconnected (power transmission efficiency w _ij = 0 (open)).

  The simulation results when the parameters are updated synchronously by the synchronous update method are shown in FIGS.

Figure 24 is a graph showing temporal changes of the supply power P _i from power plants nodes observed by simulation for Smart Grid (node 1). Figure 25 is a graph showing the time variation of power B _j supplied to the capacitor observed by simulation for smart grid (node 17). FIG. 26 is a graph showing temporal changes in the power transmission efficiency w _ij observed by the simulation for the smart grid. FIG. 27 is a graph showing the time change of the objective function R observed by the simulation of the smart grid.

As shown in FIG. 24, the supply power P _i from power plants node increases monotonically, after start of the simulation 120 step (convergent calculation count: 120) in that it reaches a stable value of "2.2" I understand. In addition, as shown in FIG. 25, power B _j supplied to the battery (for example, node 17) gradually increases so as to satisfy the minimum value of power B _j (that is, minimum allowable power B _j ^min ). I understand that.

Furthermore, as shown in FIG. 26, all the power transmission efficiencies w _ij , w _jk , and w _ik between the power nodes all converge to stable values in the range of 0.0 to 0.25. Recognize. As shown in FIG. 27, it can be seen that the value of the objective function R also decreases smoothly and reaches a stable point of about “150”.

Next, it is assumed that an accident occurs at the time of 250 steps in the above-described simulation of the microgrid. That is, in step 250, the distribution node P ′ _i and the storage node B _j are disconnected (power transmission efficiency w _ij = 0 (open)).

As shown in FIG. 26, since the power from the power distribution station nodes P _{'i (node} 8) is not supplied directly to the capacitor node B _{j (node} 17), as shown in FIG. 25 in the electric storage pack Node B _j The electric power of the power source instantaneously decreases at 250 steps where the accident occurred. On the other hand, the supplied power P _i from the power plant node varies only slightly.

Except for the power transmission path w _ik set to “0”, the power supply is restored by the detour transmission path. FIG. 26 shows a state where the power transmission efficiency w _ij between the power distribution node P ′ _i and the battery node B _j is recovered with time. That is, after the power transmission efficiency w _ij is once reduced to “0” in 250 steps, the power transmission efficiency via the detour transmission path is increased. That is, it can be seen that the power supply is recovered via the detour transmission path.

  On the other hand, as shown in FIG. 27, it can be seen that even when such an accident occurs, the value of the objective function R hardly fluctuates. This simulation shows the robustness (robustness) of the microgrid.

  Next, simulation results using the asynchronous update method for updating the control variable at an arbitrary timing under the same conditions as described above are shown in FIGS.

Figure 28 is a graph showing temporal changes of the supply power P _i from power plants nodes observed by simulation for Smart Grid (node 1). Figure 29 is a graph showing the time variation of power B _j supplied to the capacitor observed by simulation for smart grid (node 17). FIG. 30 is a graph showing the time change of the power transmission efficiency w _ij observed by the simulation of the smart grid. FIG. 31 is a graph showing the time change of the objective function R observed by the simulation for the smart grid.

  28 to 31 are similar to the simulation results shown in FIGS. 24 to 27 described above.

<E. Other considerations>
(E1. Demand fluctuation over time)
In the above-described embodiment, modeling is performed under some constraint conditions. In general, the objective function R is a nonlinear function that changes with time. For example, the demand power _Dk always changes with time. For example, the demand power _Dk increases during the day and decreases during the night.

Under such conditions, for example, the following function can be adopted as the demand power D _k (t) that varies with time.

Here, a _k indicates the amplitude, θ _k indicates the phase of the k-th demand node, and b _k is an offset, which has a margin of about 20% with respect to the maximum allowable power Q _k ^max . , Ε = 0.8.

When the demand power D _k (t) fluctuates with time, the convergence calculation that minimizes the objective function R described above is executed again, and the state of the power flow changes so that the value of the objective function R is minimized.

In the power supply / demand control system according to the present embodiment, by appropriately updating the supply power P _i from the power plant node and the transmission rates x _ij , x _jk , x _ik , Respond to fluctuations.

Note that the demand power D _k (t) that fluctuates with time is not a fixed function as described above, but a fluctuation model at each demand node is estimated by learning control as will be described later. Control may be performed using a variation model.

(E2. Presence of renewable energy sources)
Referring again to FIG. 10, when storage node B _j belongs to power plant node P _i and storage node B _{j ′} belongs to demand node Q _k , storage node B _j is charged. Sometimes, the power transmission efficiency w _j′j corresponds to a power supply path from the capacitor node B _{j ′} to the capacitor node B _j . This situation corresponds to the case where the customer Q _k sells power from the battery B _{j ′} to the power supply side P _i through the battery B _j .

Here, if the capacitor node or the demand node does not have sufficient capacity to receive power from other capacitor nodes or power plant nodes, the maximum allowable power B _j ^max of the capacitor node is expressed by the following function: By adopting, the maximum power storage capacity can be increased.

That is, at the time of calculating the convergence of the objective function R, the maximum allowable power B _j ^max is sequentially updated according to the following formula.

B _j ^max (t + 1) = B _j ^max (t) + ΔB _j ^max
Similarly, the maximum allowable power Q _k ^max of the demand node can be increased by adopting the following function.

That is, when calculating the convergence of the objective function R, the maximum allowable power Q _k ^max is sequentially updated according to the following formula.

Q _k ^max (t + 1) = Q _k ^max (t) + ΔQ _k ^max
By adopting the functions described above, even if renewable natural energy sources such as solar power generation, wind power generation, and biomass power generation are included in the configuration of the smart grid, appropriate power supply / demand Control becomes possible.

(E3. Smart grid topology change)
In particular, in a smart grid, a small power source (power plant) is easily added, or a battery (battery) is easily added. Alternatively, the power supply path (power network cable) may be interrupted due to some accident or repair.

In such a case, the topology of the smart grid changes as a whole. Even in such a case, in the power supply / demand control system according to the present embodiment, the value of the corresponding one of the transmission rates x _ij and x _jk included in the objective function R indicates the cutoff state “ By fixing to either “0 (open)” or “1 (close)” indicating the conduction state, it is possible to easily cope with such a topology change.

<F. Load fluctuation prediction by learning>
The power supply / demand control as described above is realized by a hierarchical structure such as a physical layer including the field controller shown in FIG. 1 and a control plane (Control Plane) including the controller 100 shown in FIG.

  A prediction learning layer for predicting future fluctuations in demand can be added to such a hierarchical structure.

(F1. Architecture)
FIG. 32 is a diagram schematically showing an example of a network architecture in which service layers for making a demand prediction according to the present embodiment are integrated.

  The network architecture shown in FIG. 32 has a smart grid layer for monitoring and controlling an actual smart grid. This smart grid layer is a physical layer located at the lowest layer of the network architecture.

  On the other hand, a prediction learning layer for predicting future fluctuations in demand is located in the uppermost layer of the network architecture. This predictive learning layer corresponds to an application layer or a service layer in the network hierarchy.

  Furthermore, a middleware layer (Middle Ware Layer) for integrating the two is located between the smart grid layer and the predictive learning layer. Strictly speaking, the middleware layer is implemented as a pseudo layer, and controls the power flow in the smart grid layer based on a learning value (function) of a future change in demand predicted by the prediction learning layer. That is, the above-described convergence calculation is performed so that the objective function R takes the minimum value.

  The middleware layer can improve the prediction accuracy by feeding back the control error signal to the prediction learning layer when the demand for power demand is not satisfied at the demand node or the capacitor node of the smart grid layer. Further, when any new node is added to the smart grid layer, the middleware layer notifies the prediction learning layer of the added content. The predictive learning layer copes with the change in the node configuration in the smart grid layer by changing the topology of the virtual network.

  The example shown in FIG. 32 shows an example of mounting on an existing network architecture. However, when it is mounted on a new generation network that is currently being researched and developed and is expected to be put into practical use after 4 to 5 years. Can adopt an architecture as shown in FIG.

  FIG. 33 is a diagram schematically showing an example of a network architecture when the system according to the present embodiment is mounted on a new generation network. Referring to FIG. 33, the predictive learning layer is implemented in a service layer positioned at the upper level of the new generation network architecture.

  In the new generation network architecture, a virtual network layer (Virtualization Layer) is placed above the physical layer (Substrate Layer) where packets are actually exchanged, and many nodes are virtually connected to the same physical entity. Can be provided.

(F2. Predictive learning layer network configuration)
FIG. 34 is a diagram schematically showing a network configuration for realizing the predictive learning layer according to the present embodiment.

  The network shown in FIG. 34 includes a plurality of virtual nodes. Each virtual node in the network executes processing related to calculation and learning, and processing related to algorithm construction. Processing related to this calculation and learning includes processing such as agent generation, data transfer, and constant value correction. Further, the processing related to algorithm construction includes processing related to topology change such as generation and deletion of nodes and edges.

  This network includes user nodes in addition to virtual nodes. This user node collects actual user data (various detection values related to power flow in the smart grid), or processes / manages input data / teacher data as a front end of the predictive learning process.

  The basic idea for realizing the predictive learning process using such a network and the virtual nodes included therein is described in detail in the specification of Japanese Patent Application No. 2008-274282 filed earlier by the present applicants. Please refer to it.

  The predictive learning process according to the present embodiment is realized using an “algorism variable network (ATN)” disclosed in Japanese Patent Application No. 2008-274282. That is, while constructing a network as shown in FIG. 34 physically or virtually, the predictive learning layer (FIG. 33) performs algorithm learning using information input from the user node as a teacher, and relates to temporal fluctuations in demand. Build an internal model.

(F3. Algorithm learning)
FIG. 35 schematically shows an operation in algorithm learning according to the present embodiment. In the present embodiment, as shown in FIG. 32, in a state where the smart grid layer (power network) and the predictive learning layer are integrated, information from the target consumer (load site) is input from the user node. / Give as teacher data. Then, according to the generated agent, learning is performed by sequentially propagating packets (forward propagation and back propagation) between virtual nodes of the network. After sufficient time has passed, an internal model (algorithm) is obtained. This internal model corresponds to a function indicating the characteristics of demand obtained as a result of learning.

  In addition, about algorithm learning as shown in FIG. 35, it is preferable to provide independently for each consumer.

  Once such an internal model (algorithm) is constructed, based on this information, power supply / demand control using the objective function R described above is executed. That is, after the function indicating the temporal change of each demand is included in the objective function R, the control is sequentially performed so that the value of the objective function R is minimized.

  As the teacher data input from the user node, in addition to the actual demand magnitude (time change), data that has an influence on the demand magnitude, that is, data highly correlated with the demand is inputted. It is preferable. Such data highly correlated with demand can be arbitrarily selected from the following.

・ Geographic information (latitude, longitude, altitude)
・ Time information (year, month, day, hour, minute, second)
・ Temperature (maximum temperature, minimum temperature, average temperature), sunshine duration, atmospheric pressure, humidity ・ Amount of precipitation, ice, frost, fog, snow ・ Wind direction, wind speed ・ Satellite image data from meteorological satellites ・ Weather maps and weather forecasts・ Weekly weather forecast, seasonal information, typhoon information, etc. ・ Past weather data ・ Global environmental data bank information (global warming data, greenhouse gas status, El Niño occurrence, Lanilla occurrence, Heat island information, yellow sand Information, UV observation data, ozone layer status, etc.)
・ Sunspot information, volcanic eruption forecast / warning, etc. ・ Ocean data (sea temperature, ocean greenhouse gases, etc.)
The internal model (algorithm) is generated as a function having a high correlation with the information input as the teacher data.

  In the example described above, the case of predictive learning of temporal fluctuations in demand is illustrated, but temporal fluctuations in the supply amount from service nodes (mainly power supply nodes) can also be predicted and learned. For example, even a consumer may supply surplus power generated by solar power generation to a power company on the power supply side, so for such parameters that may vary over time, the algorithm learning described above is used. Can be used to create an internal model that shows its characteristics.

  Therefore, once such a model is constructed, it is possible to perform appropriate control according to the near-future power supply and demand state using the logic that determines the power flow using the objective function R described above. That is, in the near future, taking into account events such as an increase in power used at demand nodes or a decrease in the amount of power generated by renewable natural energy sources, the power generation amount of the power plant is increased in advance, or the battery ( The amount of discharge from the battery can be increased. In other words, power demand information can be pre-supplied and supplied for each user (a pre-supply system for power demand).

  That is, in the system shown in FIG. 32 and FIG. 33, means for determining a characteristic function related to the time of the amount of power (resource) consumed in the demand node by acquiring and learning actual information about the demand node. Have Then, when calculating the value of the objective function, the value of the objective function R is calculated based on the future resource consumption determined by this characteristic function.

More specifically, the maximum allowable power B _j ^max and the minimum allowable power B _j ^min related to the substation / distribution node are automatically learned in advance by using, as an internal model, data having a high correlation with demand as described above. In addition, by updating the values of the maximum allowable power Q _k ^max and the demand power D _k as needed, the objective function can be dynamically changed according to the environment.

(F4. Implementation example)
FIG. 36 schematically shows an implementation example in algorithm learning according to the present embodiment. For example, it is assumed that a value of an nth-order vector quantity x = {x _i ; 1 ≦ i ≦ n} can be acquired in time series as input data / teacher data. That is, it is assumed that the vector quantity x ^(t) = {x _i ^(t) } is given.

In such a case, for example, vector quantities x ^(t) , x ^(t−1) ,..., X ^(t−9) for 10 unit time are input in parallel to the user node as shown in FIG. Is done. The above-described algorithm learning is performed while such a vector amount input is repeated for a predetermined time, whereby an internal model is created.

<G. Other application examples>
(G1. Implementation of middleware layer)
In the above-described embodiment, the example in which the power supply / demand control system (middleware layer) is implemented using the controller 100 as illustrated in FIG. 2 has been described. However, the algorithm variable network ( A computer network similar to ATN) can also be used.

  In this case, for example, in the architecture shown in FIG. 33, the program is implemented as a program that operates immediately below the application layer, thereby constructing a computer network in an overlay network (virtual network layer) on the Internet. To do.

In this case, for example, a control signal for controlling the power supplied to the power plant is sequentially transferred on the virtual network in the form of a communication packet. Further, the capacitor node B _j and the demand node Q _k are located at locations corresponding to the respective user nodes.

  The administrator node also monitors whether the power supply network is operating normally. If a power outage accident occurs due to a disaster or the like, the power supply is automatically restored immediately through the detour transmission path. At this time, it is also possible to monitor in the management node whether or not the power supply network has been normally restored by using the state of each node and the value of the objective function R of the entire system.

  As described in detail in the specification of Japanese Patent Application No. 2008-274282, in the algorithm variable network (ATN), an algorithm is represented by a network including operation nodes and data transfer edges. The calculation process is advanced in a large-scale, massively parallel, and asynchronous manner by a data flow (agent flow) method. Further, the algorithm variable network (ATN) has an advantage that the algorithm can be modified during execution by constant value correction by error back propagation learning and edge change.

(G2. Other application examples)
In the above-described embodiment, an example in which power is applied as an example of a resource (resource) has been described. However, the present invention can also be applied to a case where natural products, general products, rare metals, and the like scattered on the earth are used as resources.

In this case, the power plant node P _i described above is associated with the production area, the substation / distribution node or the capacitor node B _j is associated with the distribution center, and the demand node Q _k is associated with the consumer. . Further, the power transmission efficiency w _ij is associated with the transportation cost.

  Further, by combining learning control (service layer) as described above, dynamic resource allocation can be performed even when the demand is too large to provide resources (resources).

<H. Effect>
According to the present embodiment, in the power supply / demand control system, the convenience of users (including both the power supply side and the power demand side) is improved, the adaptability to environmental changes such as power load fluctuations, and sudden accidents It is possible to improve various performances such as fault tolerance to the system and flexibility of system operation management. In other words, in order to realize a network-based power supply / demand control system with a higher degree of perfection, it is possible to conduct a multifaceted study from the design stage. As a result, the quality of Green ICT-related technology that is currently being developed can be further improved.

  Further, by estimating the variation model at each demand node by learning control, not only the design policy can be supplied, but also the performance in the operation of the entire system can be improved.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

  10, 20, 30, 30 Field controller 11, 21, 31, 42 Network I / F, 12, 22, 32 Sensor, 13, 23, 33 Actuator, 100 Controller, 102 Computer body, 104 Monitor, 105 Bus, 106 Flexible disk (FD) drive, 108 optical disk drive, 110 keyboard, 112 mouse, 118 ROM, 120 CPU, 122 memory, 124 hard disk, 128 communication interface, 131 objective function generation module, 132 objective function calculation module, 133 variable update module, 134 Convergence module determination, 134 Convergence determination module, 135 Parameter file.

Claims (10)

A system for performing arithmetic processing related to resource allocation in a network including a first node that generates a resource and a second node that consumes the resource,
Means for holding an objective function, wherein the objective function is:
A first function that outputs a value of a cost required for a resource supplied from the first node, monotonically increasing with respect to a resource size;
Out of the resources generated in the first node, the larger the difference between the size of the resource supplied to the second node and the size of the resource consumed in the second node, the larger the value is output. A second function having as a variable a transmission rate in a resource path from the first node to the second node, and
Means for calculating a value of the objective function based on a variable indicating a size of a resource generated in the first node and a variable indicating the transmission rate;
Means for updating a variable indicating the size of the resource by a value corresponding to a differential value obtained by partial differentiation of the objective function with a variable indicating the size of the resource;
Means for updating the variable indicating the transmission rate by a value corresponding to a differential value obtained by partial differentiation of the objective function with the variable indicating the transmission rate;
Means for repeating the calculation of the value of the objective function based on the updated value;
And a means for outputting the resource size and the transmission rate when the objective function calculation process converges. The objective function is
The system according to claim 1, further comprising a third function that outputs a larger value as the size of the resource generated in the first node approaches zero. The objective function is
The system according to claim 1, further comprising a fourth function that outputs a smaller value as the transmission rate is closer to “0” or “1”.   The variable indicating the size of the resource and the variable indicating the transmission rate are both updated before the value of the objective function is newly calculated. The described system.   The variable indicating the magnitude of the resource and the variable indicating the transmission rate are updated before the value of the objective function is newly calculated. The system described in.   6. The objective function according to claim 1, wherein the objective function calculation process is determined to have converged when the calculated value of the objective function is substantially maintained at a minimum value. 7. system. The network further includes a third node that relays the resource or stores the resource,
The second function relates to a function related to the size of resources supplied from the first node to the third node, and to a size of resources supplied from the first node to the second node. The system according to claim 1, comprising a function and a function related to a size of a resource supplied from the third node to the second node. Means for determining a characteristic function relating to the time of the size of the resource consumed in the second node by acquiring and learning real information about the second node;
The system according to claim 1, wherein the means for calculating the value of the objective function calculates the value of the objective function based on a future resource consumption determined by the characteristic function. .   The system according to claim 1, wherein the network is associated with a network that supplies power. A method for determining resource allocation in a network including a first node that generates resources and a second node that consumes the resources, comprising:
The arithmetic processing unit includes a step of holding an objective function, wherein the objective function is:
A first function that outputs a value of a cost required for a resource supplied from the first node, monotonically increasing with respect to a resource size;
Out of the resources generated in the first node, the larger the difference between the size of the resource supplied to the second node and the size of the resource consumed in the second node, the larger the value is output. A second function having as a variable a transmission rate in a resource path from the first node to the second node, and
The arithmetic processing unit calculating a value of the objective function based on a variable indicating a size of a resource generated in the first node and a variable indicating the transmission rate;
The arithmetic processing unit updating the variable indicating the size of the resource by a value corresponding to a differential value obtained by partial differentiation of the objective function with a variable indicating the size of the resource;
The arithmetic processing unit updates the variable indicating the transmission rate by a value corresponding to a differential value obtained by partial differentiation of the objective function with the variable indicating the transmission rate;
The arithmetic processing unit repeatedly calculating the value of the objective function based on the updated value;
And a step of outputting the magnitude of the resource and the transmission rate when the calculation processing of the objective function has converged.

Images