CN118841993A - Feeder load aggregator adjustable capacity calculation method, system, equipment and medium - Google Patents

Abstract

The present invention relates to a method, system, device and medium for calculating adjustable capacity of a feeder load aggregator, wherein the method comprises the following steps: a target feeder load aggregator receives a voltage adjustable amount declaration request from a user on a corresponding feeder branch, wherein the voltage adjustable amount declaration request of the user is declared by the corresponding user in combination with the voltage requirement of its own electrical equipment; the maximum adjustable amount of voltage at the feeder is obtained through power flow calculation in combination with the voltage adjustable amount declared by each user; the feeder voltage is regulated according to the maximum adjustable amount of voltage at the feeder and a voltage regulating device; and the sum of the capacity changes of all users on the feeder branch after the feeder voltage regulation is completed is calculated as the final adjustable capacity calculation result.

Description

Feeder load aggregator adjustable capacity calculation method, system, device and medium

Technical Field

The present invention relates to a method, system, equipment and medium for calculating adjustable capacity of a feeder load aggregator, and belongs to the technical field of power peak regulation and frequency regulation assistance.

Background Art

The research and application of tapping into the flexible and adjustable resources on the user side to participate in the peak and frequency regulation of the power grid has received widespread attention. As an important part of the adjustable resources on the user side, feeder load plays a vital role in participating in the peak and frequency regulation of the power grid and maintaining the power balance of the system. However, the current research on the participation of feeder load in the interaction of the power grid is still incomplete. Feeder load aggregators have gradually become a new role in the power market. Feeder load aggregators play an important role in centralized management, optimized allocation, and market-based transactions for power users on feeder branches. However, the interactive mechanism for how feeder load aggregators can efficiently participate in the market has not yet been put into practical operation on a large scale.

The voltage at the feeder adjusted by the feeder load aggregator will affect the power voltage of all power users under the feeder branch. Therefore, how the feeder load aggregator can adjust the voltage at the feeder to make the voltage change of all users under the feeder branch within an acceptable range while considering the user's wishes has become a hot issue in this field. How the feeder load aggregator can adjust the feeder voltage in accordance with the user's wishes and report the adjustable capacity to the power peak and frequency regulation market has become a hot issue in this field.

Summary of the invention

In order to solve the above problems existing in the prior art, the present invention proposes a method, system, device and medium for calculating the adjustable capacity of a feeder load aggregator.

The technical solution of the present invention is as follows:

On the one hand, the present invention provides a method for calculating the adjustable capacity of a feeder load aggregator, comprising the following steps:

The target feeder load aggregator receives a voltage adjustable amount declaration request from a user on a corresponding feeder branch, where the voltage adjustable amount declaration request is made by the corresponding user in combination with the voltage requirements of its own electrical equipment;

Combined with the adjustable voltage reported by each user, the maximum adjustable voltage at the feeder is obtained through power flow calculation;

Regulating the feeder voltage according to the maximum adjustable amount of the voltage at the feeder and the voltage regulating device;

The sum of the capacity changes of all users on the feeder branch after the feeder voltage regulation is calculated as the final regulated capacity calculation result.

As a preferred implementation, the step of obtaining the maximum adjustable voltage at the feeder by power flow calculation in combination with the adjustable voltage reported by each user is specifically as follows:

Get the power flow relationship between the i-th user and the feeder before feeder voltage regulation:

;

;

;

in, It indicates the line power loss between the feeder and the user before the feeder voltage is regulated; is the rated voltage at the feeder; are the active power, reactive power, total power and voltage of the ith user before feeder voltage regulation, R and X are the line resistance and reactance parameters between the feeder and the ith user, respectively. are the active power, reactive power, total power and voltage of the i-th user at feeder k respectively;

Get the power flow relationship between the i-th user and the feeder after feeder voltage regulation:

;

;

;

in, It indicates the line power loss between the feeder and the user before the feeder voltage is regulated; are the active power, reactive power, total power and voltage of the i-th user after feeder voltage regulation, are respectively the active power, reactive power, total power and voltage of the i-th user at feeder k after feeder voltage regulation;

Get the voltage regulation at the feeder The functional relationship between the voltage change of the user is:

;

in, ; The adjustable voltage reported by the i-th user; It represents the functional relationship between the voltage regulation at the feeder and the voltage change of the user;

Calculate the maximum adjustable voltage at the feeder :

;

in, Indicates the total number of users.

As a preferred implementation, the calculation method of the active power and reactive power of the i-th user after the feeder voltage is adjusted is specifically as follows:

;

;

Wherein, A and B are the voltage-power coupling coefficients of the i-th user, representing the coupling relationship between the voltage change of the user and the power change caused by the voltage change of the user.

As a preferred implementation, the method for calculating the sum of capacity changes of all users on the feeder branch after the feeder voltage regulation is completed is specifically as follows:

The active power change of the i-th user on the feeder branch before and after the feeder voltage regulation is obtained as the capacity change of each user after the feeder voltage regulation:

;

Calculate the sum of capacity changes of each user:

.

On the other hand, the present invention also provides a feeder load aggregator adjustable capacity calculation system, comprising:

A user intention acquisition module is used to acquire a voltage adjustable amount declaration request from a user on a corresponding feeder branch, where the voltage adjustable amount declaration request is made by the corresponding user in combination with the voltage requirements of his own electrical equipment;

The adjustment amount calculation module is used to obtain the maximum adjustable amount of voltage at the feeder through power flow calculation based on the adjustable amount of voltage reported by each user;

A feeder voltage regulation module, which regulates the feeder voltage according to the maximum adjustable amount of the voltage at the feeder and the voltage regulation device;

The adjustable capacity calculation module is used to calculate the sum of the capacity changes of all users on the feeder branch after the feeder voltage regulation is completed as the final adjustment capacity calculation result.

As a preferred implementation, the step of obtaining the maximum adjustable voltage at the feeder by power flow calculation in combination with the adjustable voltage reported by each user is specifically as follows:

Get the power flow relationship between the i-th user and the feeder before feeder voltage regulation:

;

;

;

in, It indicates the line power loss between the feeder and the user before the feeder voltage is regulated; is the rated voltage at the feeder; are the active power, reactive power, total power and voltage of the ith user before feeder voltage regulation, R and X are the line resistance and reactance parameters between the feeder and the ith user, respectively. are the active power, reactive power, total power and voltage of the i-th user at feeder k respectively;

Get the power flow relationship between the i-th user and the feeder after feeder voltage regulation:

;

;

;

in, It indicates the line power loss between the feeder and the user before the feeder voltage is regulated; are the active power, reactive power, total power and voltage of the i-th user after feeder voltage regulation, are respectively the active power, reactive power, total power and voltage of the i-th user at feeder k after feeder voltage regulation;

Get the voltage regulation at the feeder The functional relationship between the voltage change of the user is:

;

in, ; The adjustable voltage reported by the i-th user; It represents the functional relationship between the voltage regulation at the feeder and the voltage change of the user;

Calculate the maximum adjustable voltage at the feeder :

;

in, Indicates the total number of users.

As a preferred implementation, the calculation method of the active power and reactive power of the i-th user after the feeder voltage is adjusted is specifically as follows:

;

;

Wherein, A and B are the voltage-power coupling coefficients of the i-th user, representing the coupling relationship between the voltage change of the user and the power change caused by the voltage change of the user.

As a preferred implementation, the method for calculating the sum of capacity changes of all users on the feeder branch after the feeder voltage regulation is completed is specifically as follows:

The active power change of the i-th user on the feeder branch before and after the feeder voltage regulation is obtained as the capacity change of each user after the feeder voltage regulation:

;

Calculate the sum of capacity changes of each user:

.

On the other hand, the present invention further proposes an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, a method for calculating the adjustable capacity of a feeder load aggregator as described in any embodiment of the present invention is implemented.

On the other hand, the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements a feeder load aggregator adjustable capacity calculation method as described in any embodiment of the present invention.

The present invention has the following beneficial effects:

The present invention provides a method for calculating the adjustable capacity of a feeder load aggregator. First, the user's willingness is obtained through the adjustable voltage amount reported by the user. On the basis of considering the user's willingness, the feeder load aggregator calculates the maximum voltage adjustment amount at the feeder according to the adjustable voltage amount reported by the user himself and the power flow relationship. After completing the voltage adjustment, the adjustable capacity is calculated and reported to the power auxiliary service market, which improves the enthusiasm of power users to participate in power auxiliary services and provides reference value for feeder load aggregators to efficiently participate in the interaction of the power market.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a method flow chart of Embodiment 1 of the present invention.

DETAILED DESCRIPTION

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

It should be understood that the step numbers used in this document are only for convenience of description and are not intended to limit the order in which the steps are executed.

It should be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

The terms “include” and “comprising” indicate the presence of described features, integers, steps, operations, elements and/or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or combinations thereof.

The term "and/or" means and includes any and all possible combinations of one or more of the associated listed items.

Embodiment 1:

Referring to FIG. 1 , this embodiment proposes a method for calculating the adjustable capacity of a feeder load aggregator, comprising the following steps:

Step 1: The target feeder load aggregator receives a voltage adjustable amount declaration request from a user on a corresponding feeder branch. The voltage adjustable amount declaration request is made by the corresponding user to the load aggregator in combination with the voltage requirements of its own electrical equipment.

That is, the target feeder load aggregator receives the voltage adjustable amount declared by each user and forms a voltage adjustable amount declaration set of the aggregated users:

;

;

in, The adjustable voltage reported by the i-th user is the maximum voltage change caused by feeder voltage adjustment that the corresponding user can accept. and are the voltages of the i-th user before and after feeder voltage regulation respectively.

Step 2: The target feeder load aggregator calculates the maximum adjustable voltage at the feeder by combining the adjustable voltage reported by each user through power flow calculation.

Step 3: The target feeder load aggregator uses a voltage regulating device to adjust the feeder voltage according to the maximum adjustable amount of the voltage at the feeder calculated in step 2.

Step 4: The target feeder load aggregator calculates the sum of the capacity changes of all users on the feeder branch after the feeder voltage regulation is completed, which is used as the final regulation capacity calculation result, and can be used as the final regulation capacity reported to the power peak and frequency regulation auxiliary service market.

As a preferred implementation of this embodiment, in step 2, the step of obtaining the maximum adjustable voltage at the feeder through power flow calculation in combination with the adjustable voltage reported by each user is specifically as follows:

S201, obtaining the power flow relationship between the i-th user and the feeder before feeder voltage regulation:

;

;

;

in, It indicates the line power loss between the feeder and the user before the feeder voltage is regulated; is the rated voltage at the feeder; are the active power, reactive power, total power and voltage of the ith user before feeder voltage regulation, R and X are the line resistance and reactance parameters between the feeder and the ith user, respectively. are the active power, reactive power, total power and voltage of the i-th user at feeder k respectively.

S202, obtaining the power flow relationship between the i-th user and the feeder after the feeder voltage is adjusted:

;

;

;

in, It indicates the line power loss between the feeder and the user before the feeder voltage is regulated; are the active power, reactive power, total power and voltage of the i-th user after feeder voltage regulation, They are respectively the active power, reactive power, total power and voltage of the i-th user at feeder k after feeder voltage regulation.

In one embodiment, after the feeder voltage is adjusted, the active power and reactive power of the i-th user are The specific calculation method is:

;

;

Wherein, A and B represent the voltage-power coupling coefficient and voltage-reactive power coupling coefficient of the i-th user, respectively, representing the coupling relationship between the voltage change of the user and the power change caused by the voltage change of the user.

S203: jointly obtain the power flow relationship between the i-th user and the feeder before and after the feeder voltage is regulated, and obtain the voltage regulation value at the feeder The functional relationship between the voltage change of the user is:

;

in, ; The adjustable voltage reported by the i-th user; It represents the functional relationship between the voltage regulation at the feeder and the voltage change of the user;

Calculate the maximum adjustable voltage at the feeder :

S204. Since the voltage regulation at the feeder affects the power voltage of all power users under the feeder branch, the voltage regulation at the feeder should make the voltage variation of all users under the feeder branch within the acceptable range. The maximum adjustable voltage at the feeder is calculated. The following relationship should be satisfied:

;

in, Indicates the total number of users.

As a preferred implementation of this embodiment, in step 4, the method for calculating the sum of the capacity changes of all users on the feeder branch after the feeder voltage regulation is completed is specifically:

The active power change of the i-th user on the feeder branch before and after the feeder voltage regulation is obtained as the capacity change of each user after the feeder voltage regulation:

;

Finally, the feeder load aggregator calculates the sum of the capacity changes of each user as the regulation capacity reported to the power peak and frequency regulation auxiliary service market. :

.

In this embodiment, based on the consideration of the user's wishes, the feeder load aggregator calculates the maximum voltage adjustment amount at the feeder according to the adjustable voltage amount declared by the user himself and the power flow relationship, calculates the adjustable capacity after completing the voltage adjustment, and reports it to the power auxiliary service market, thereby increasing the enthusiasm of power users to participate in power auxiliary services and providing reference value for feeder load aggregators to efficiently participate in the interaction of the power market.

Embodiment 2:

This embodiment provides a feeder load aggregator adjustable capacity calculation system, including:

A user intention acquisition module is used to obtain a voltage adjustable amount declaration request from a user on a corresponding feeder branch, where the voltage adjustable amount declaration request is made by the corresponding user in combination with the voltage requirements of his own electrical equipment; this module is used to implement the function of step 1 in the first embodiment, and will not be described in detail here;

An adjustment amount calculation module is used to obtain the maximum adjustable amount of voltage at the feeder through power flow calculation in combination with the adjustable amount of voltage reported by each user; this module is used to implement the function of step 2 in embodiment 1, which will not be described in detail here;

A feeder voltage regulating module, which regulates the feeder voltage according to the maximum adjustable amount of the voltage at the feeder and the voltage regulating device; this module is used to implement the function of step 3 in the first embodiment, and will not be described in detail here;

The adjustable capacity calculation module is used to calculate the sum of the capacity changes of all users on the feeder branch after the feeder voltage regulation is completed as the final adjustable capacity calculation result; this module is used to implement the function of step 4 in embodiment 1 and will not be repeated here.

As a preferred implementation of this embodiment, the step of obtaining the maximum adjustable voltage at the feeder through power flow calculation in combination with the adjustable voltage reported by each user is specifically as follows:

Get the power flow relationship between the i-th user and the feeder before feeder voltage regulation:

;

;

;

in, It indicates the line power loss between the feeder and the user before the feeder voltage is regulated; is the rated voltage at the feeder; are the active power, reactive power, total power and voltage of the ith user before feeder voltage regulation, R and X are the line resistance and reactance parameters between the feeder and the ith user, respectively. are the active power, reactive power, total power and voltage of the i-th user at feeder k respectively;

Get the power flow relationship between the i-th user and the feeder after feeder voltage regulation:

;

;

;

in, It indicates the line power loss between the feeder and the user before the feeder voltage is regulated; are the active power, reactive power, total power and voltage of the i-th user after feeder voltage regulation, are respectively the active power, reactive power, total power and voltage of the i-th user at feeder k after feeder voltage regulation;

Get the voltage regulation at the feeder The functional relationship between the voltage change of the user is:

;

in, ; The adjustable voltage reported by the i-th user; It represents the functional relationship between the voltage regulation at the feeder and the voltage change of the user;

Calculate the maximum adjustable voltage at the feeder :

;

in, Indicates the total number of users.

As a preferred implementation of this embodiment, the calculation method of the active power and reactive power of the i-th user after the feeder voltage is adjusted is specifically:

;

;

Wherein, A and B are the voltage-power coupling coefficients of the i-th user, representing the coupling relationship between the voltage change of the user and the power change caused by the voltage change of the user.

As a preferred implementation of this embodiment, the method for calculating the sum of capacity changes of all users on the feeder branch after the feeder voltage regulation is completed is specifically:

The active power change of the i-th user on the feeder branch before and after the feeder voltage regulation is obtained as the capacity change of each user after the feeder voltage regulation:

;

Calculate the sum of capacity changes of each user:

.

Embodiment three:

This embodiment proposes an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, a method for calculating the adjustable capacity of a feeder load aggregator as described in any embodiment of the present invention is implemented.

Embodiment 4:

This embodiment provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, a method for calculating the adjustable capacity of a feeder load aggregator as described in any embodiment of the present invention is implemented.

In the embodiments of the present application, "at least one" refers to one or more, and "more than one" refers to two or more. "And/or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and/or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character "/" generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, c can be single or multiple.

Those of ordinary skill in the art will appreciate that the various units and algorithm steps described in the embodiments disclosed herein can be implemented in a combination of electronic hardware, computer software, and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

In several embodiments provided in the present application, if any function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory; hereinafter referred to as: ROM), random access memory (Random Access Memory; hereinafter referred to as: RAM), disk or optical disk, and other media that can store program codes.

The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims (8)

1. A method for calculating the adjustable capacity of a feeder load aggregator, characterized by comprising the following steps: The target feeder load aggregator receives a voltage adjustable amount declaration request from a user on a corresponding feeder branch, where the voltage adjustable amount declaration request is made by the corresponding user in combination with the voltage requirements of its own electrical equipment; Combined with the adjustable voltage reported by each user, the maximum adjustable voltage at the feeder is obtained through power flow calculation; Regulating the feeder voltage according to the maximum adjustable amount of the voltage at the feeder and the voltage regulating device; Calculate the sum of capacity changes of all users on the feeder branch after feeder voltage regulation is completed as the final regulation capacity calculation result; The step of obtaining the maximum adjustable voltage at the feeder by power flow calculation in combination with the adjustable voltage reported by each user is specifically as follows: Get the power flow relationship between the i-th user and the feeder before feeder voltage regulation: ; ; ; in, It indicates the line power loss between the feeder and the user before the feeder voltage is regulated; is the rated voltage at the feeder; are the active power, reactive power, total power and voltage of the ith user before feeder voltage regulation, R and X are the line resistance and reactance parameters between the feeder and the ith user, respectively. are the active power, reactive power, total power and voltage of the i-th user at feeder k respectively; Get the power flow relationship between the i-th user and the feeder after feeder voltage regulation: ; ; ; in, It indicates the line power loss between the feeder and the user before the feeder voltage is regulated; are the active power, reactive power, total power and voltage of the i-th user after feeder voltage regulation, are respectively the active power, reactive power, total power and voltage of the i-th user at feeder k after feeder voltage regulation; Get the voltage regulation at the feeder The functional relationship between the voltage change of the user is: ; in, ; The adjustable voltage reported by the i-th user; It represents the functional relationship between the voltage regulation at the feeder and the voltage change of the user; Calculate the maximum adjustable voltage at the feeder : ; in, Indicates the total number of users. 2. A method for calculating the adjustable capacity of a feeder load aggregator according to claim 1, characterized in that the calculation method of the active power and reactive power of the i-th user after the feeder voltage is adjusted is specifically as follows: ; ; Wherein, A and B are the voltage-power coupling coefficients of the i-th user, representing the coupling relationship between the voltage change of the user and the power change caused by the voltage change of the user. 3. According to the method for calculating the adjustable capacity of a feeder load aggregator of claim 1, it is characterized in that the method for calculating the sum of the capacity changes of all users on the feeder branch after the feeder voltage adjustment is completed is specifically: The active power change of the i-th user on the feeder branch before and after the feeder voltage regulation is obtained as the capacity change of each user after the feeder voltage regulation: ; Calculate the sum of capacity changes of each user: . 4. A feeder load aggregator adjustable capacity calculation system, characterized by comprising: A user intention acquisition module is used to acquire a voltage adjustable amount declaration request from a user on a corresponding feeder branch, where the voltage adjustable amount declaration request is made by the corresponding user in combination with the voltage requirements of his own electrical equipment; The adjustment amount calculation module is used to obtain the maximum adjustable amount of voltage at the feeder through power flow calculation based on the adjustable amount of voltage reported by each user; A feeder voltage regulation module, which regulates the feeder voltage according to the maximum adjustable amount of the voltage at the feeder and the voltage regulation device; The adjustable capacity calculation module is used to calculate the sum of the capacity changes of all users on the feeder branch after the feeder voltage regulation is completed as the final adjustment capacity calculation result; The step of obtaining the maximum adjustable voltage at the feeder by power flow calculation in combination with the adjustable voltage reported by each user is specifically as follows: Get the power flow relationship between the i-th user and the feeder before feeder voltage regulation: ; ; ; in, It indicates the line power loss between the feeder and the user before the feeder voltage is regulated; is the rated voltage at the feeder; are the active power, reactive power, total power and voltage of the ith user before feeder voltage regulation, R and X are the line resistance and reactance parameters between the feeder and the ith user, respectively. are the active power, reactive power, total power and voltage of the i-th user at feeder k respectively; Get the power flow relationship between the i-th user and the feeder after feeder voltage regulation: ; ; ; in, It indicates the line power loss between the feeder and the user before the feeder voltage is regulated; are the active power, reactive power, total power and voltage of the i-th user after feeder voltage regulation, are respectively the active power, reactive power, total power and voltage of the i-th user at feeder k after feeder voltage regulation; Get the voltage regulation at the feeder The functional relationship between the voltage change of the user is: ; in, ; The adjustable voltage reported by the i-th user; It represents the functional relationship between the voltage regulation at the feeder and the voltage change of the user; Calculate the maximum adjustable voltage at the feeder : ; in, Indicates the total number of users. 5. A feeder load aggregator adjustable capacity calculation system according to claim 4, characterized in that the calculation method of the active power and reactive power of the i-th user after the feeder voltage is adjusted is specifically: ; ; Wherein, A and B are the voltage-power coupling coefficients of the i-th user, representing the coupling relationship between the voltage change of the user and the power change caused by the voltage change of the user. 6. A feeder load aggregator adjustable capacity calculation system according to claim 4, characterized in that the method for calculating the sum of capacity changes of all users on the feeder branch after the feeder voltage adjustment is completed is specifically: The active power change of the i-th user on the feeder branch before and after the feeder voltage regulation is obtained as the capacity change of each user after the feeder voltage regulation: ; Calculate the sum of capacity changes of each user: . 7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method according to any one of claims 1 to 3 when executing the program. 8. A computer-readable storage medium having a computer program stored thereon, wherein when the program is executed by a processor, the method according to any one of claims 1 to 3 is implemented.