Method for evaluating operation reliability of converter valve of ultrahigh-voltage flexible direct-current power transmission system

Abstract

A converter valve operation reliability evaluation method for an ultrahigh-voltage flexible direct-current power transmission system belongs to the technical evaluation field of converter valves, and comprises the following steps: obtaining a topological structure of a converter valve, and establishing a bridge arm sub-module reliability function derivation diagram of the converter valve; historical data of the converter valve are obtained, and a bridge arm sub-module fault rate is obtained by establishing a bridge arm sub-module fault rate time-varying characteristic function of the converter valve; deriving a reliability function of the converter valve according to the reliability function derivation schematic diagram of the converter valve and the fault rate of the bridge arm sub-module; and obtaining the reliability index of the converter valve by means of the transfer rate matrix of the converter valve operation state transfer process and the Markov random process model. By improving the evaluation algorithm, the accuracy and adaptability of the evaluation algorithm are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of operating reliability assessment of flexible direct current converter valves in ultra-high voltage flexible direct current transmission systems, and in particular, relates to an operating reliability assessment method and system for converter valves in ultra-high voltage flexible direct current transmission systems. Background Art

[0002] As a new type of DC transmission technology, ultra-high voltage flexible DC transmission avoids the problems of reactive power compensation and commutation failure in traditional DC transmission technology. It also has the advantages of flexible control, low harmonic level and strong fault handling ability, providing effective technical support for long-distance transmission of electric energy, and playing an increasingly important role in the new power system. As one of the important components in the ultra-high voltage flexible DC transmission system, the converter valve has the functions of AC-DC conversion, frequency and voltage regulation, fault detection and protection, and plays a vital role in the process of long-distance transmission of electric energy and energy exchange between power grids.

[0003] However, in actual operation, flexible direct current valves may fail or degrade in performance due to various reasons. It is necessary to promptly inspect and repair valves with operating risks to ensure their normal operation. With the continuous development of technologies such as online equipment monitoring and real-time communication, equipment maintenance strategies are gradually shifting from traditional periodic maintenance to condition-based maintenance. Compared with the traditional periodic maintenance model, condition-based maintenance predicts possible equipment failures based on the operating status of the equipment and formulates customized maintenance strategies. It can more accurately grasp the maintenance intensity of equipment in different operating states, set more flexible equipment maintenance cycles, and improve the efficiency and overall economy of operation and maintenance work.

[0004] The reliability assessment of converter valve operation in ultra-high voltage flexible direct current transmission system can provide strong information support for the status inspection of converter valve. At present, the reliability assessment method of converter valve in ultra-high voltage flexible direct current transmission system is still used in the reliability assessment method of converter valve in traditional direct current transmission system. It is usually assumed that the converter valve in ultra-high voltage flexible direct current transmission system only has two states: normal operation and fault shutdown, and the failure rate of valve components is constant. This idea ignores the multi-state characteristics of converter valve in ultra-high voltage flexible direct current transmission system and cannot meet the increasingly accurate reliability analysis needs. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for evaluating the operating reliability of a converter valve in an ultra-high voltage flexible direct current transmission system, and the accuracy and adaptability of the evaluation algorithm are improved by improving the evaluation algorithm.

[0006] The technical solution adopted by the present invention is: a method for evaluating the operation reliability of a converter valve of an ultra-high voltage flexible direct current transmission system, the method comprising the following steps: S01. Obtain the topological structure of the converter valve and establish a schematic diagram of the derivation of the reliability function of the bridge arm submodule of the converter valve; S02. Obtain historical data of the converter valve, and obtain the failure rate of the bridge arm submodule by establishing a time-varying characteristic function of the failure rate of the bridge arm submodule of the converter valve; S03. According to the reliability function derivation diagram of the converter valve and the failure rate of the bridge arm submodule, the reliability function of the converter valve is derived; S04. With the help of the transfer rate matrix of the converter valve operation state transfer process and the Markov random process model, the reliability index of the converter valve is obtained.

[0007] Further, the valve topology structure includes m bridge arms, each bridge arm includes n bridge arm submodules and 1 bridge arm reactance L; The schematic diagram for deriving the reliability function of the bridge arm submodule includes an IGBT valve group C1, a resistor C2, a capacitor C3, a control protection circuit C4 and an energy extraction circuit C5.

[0008] Furthermore, the historical data of the converter valve includes: information data before the converter valve operation, converter valve operation data, converter valve maintenance data, and converter valve family defect data.

[0009] Furthermore, the process of establishing the time-varying characteristic function of the failure rate of the bridge arm submodule of the converter valve includes: First, establish the failure rate formula η of the bridge arm submodule r，s for: , Among them, θ r,s Representative The number of failures of the bridge arm submodule Cr in each subinterval; r represents the serial number of the bridge arm submodule r∈ (1, 2, 3…5); s represents the time interval The number of subintervals that evenly divide the entire observation time, s∈(1,2,3…s); Then, based on the subinterval s and the failure rate η r，s Based on engineering experience, the segmented fitting method is used to obtain the time-varying characteristic function ηr(t) of the failure rate of the bridge arm submodule Cr. , Among them, t r，1 and t r，2 is the turning point of the failure rate of the bridge arm submodule Cr; ηr(t) is in [0, t r，1 ] is a strictly monotonically decreasing function. r，1 , t r，2 ] is approximately a constant, in [t r，2 ,+∞] is a strictly monotonically increasing function, so η r (t) The interval failure rate is stable, so ηr is selected as the failure rate of the bridge arm submodule Cr.

[0010] Furthermore, the derivation process of the converter valve reliability function includes: First, the reliability function K(t) of the bridge arm submodule Cr is established. , Among them, η1 represents the failure rate of the IGBT valve group C1, η2 represents the failure rate of the resistor C2, η3 represents the failure rate of the capacitor C3, η4 represents the failure rate of the control protection circuit C4, and η5 represents the failure rate of the energy extraction circuit C5; Then, since the topological structure of a single bridge arm is the same, the reliability function Karm(t) of the converter valve is: , Among them, n represents the total number of bridge arm submodules, and q represents the minimum required number of bridge arm submodules when the converter valve is in operation.

[0011] Furthermore, the transfer rate matrix is: A = , Among them, δ is the maintenance rate of the ultra-high voltage flexible direct current converter valve bridge arm, q represents the minimum required number of bridge arm submodules when the converter valve is in operation, and n represents the total number of bridge arm submodules; Based on the Markov random process model, the reliability index of the converter valve is obtained: The steady-state probability index pi of the converter valve operation state, , Where, i∈(0,1,2…,n-q+1); Frequency index fi of converter valve operation status, , Among them, is the transfer rate matrix The element in the i-th row and j-th column in represents the transition rate from operating state i to operating state j (j≠i); Expected indicators of converter valve operation duration , .

[0012] A converter valve operation reliability assessment system for an ultra-high voltage flexible direct current transmission system implements the above method, and the system comprises: A reliability function derivation schematic diagram construction module is used to obtain a converter valve topology structure and establish a converter valve reliability function derivation schematic diagram; A failure rate time-varying characteristic analysis module is used to obtain historical data of the converter valve and analyze the failure rate time-varying characteristics of the converter valve bridge arm submodule; A reliability function derivation module is used to derive a failure rate function of a converter valve bridge arm submodule, and then derive a converter valve reliability function; The reliability index calculation module is used to consider the operation state transition process of the converter valve and then solve the reliability index of the converter valve based on the Markov random process model.

[0013] An electronic device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above-mentioned method when executing the computer program.

[0014] A non-transitory computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the steps of the method described above are implemented.

[0015] A computer program product comprises a computer program, wherein the computer program implements the steps of the above method when executed by a processor.

[0016] The beneficial effects produced by the use of the present invention are as follows: the analysis of the time-varying characteristics of the failure rate of the bridge arm submodule of the ultra-high voltage flexible direct current converter valve provides a strong support for the derivation of the bridge arm submodule reliability function, the failure rate function relationship and the reliability function of the ultra-high voltage flexible direct current converter valve. The consideration of the state transfer process of the ultra-high voltage flexible direct current converter valve in the reliability assessment model improves the scientificity and accuracy of the reliability assessment results of the converter valve of the ultra-high voltage flexible direct current transmission system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the process of the present invention; Figure 2 Schematic diagram of the topological structure of the converter valve of the present invention; Figure 3 1. It is a schematic diagram of the derivation of the reliability function of the converter valve of the present invention; Figure 4 This is the state transfer process of the converter valve of the present invention; Figure 5 is a schematic diagram of the structure of an electronic device provided by the present invention; Figure 6 It is a schematic diagram of the physical structure of the electronic device provided by the present invention.

[0018] In the accompanying drawings: 110 is a reliability function derivation schematic diagram construction module, 120 is a failure rate time-varying characteristic analysis module; 130 is a reliability function derivation module, 140 is a reliability index calculation module, 2010 is a processor, 2020 is a communication interface, 2030 is a memory, and 2040 is a communication bus. DETAILED DESCRIPTION

[0019] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0020] See attached Figure 1-5 , a method for evaluating the operation reliability of a converter valve of an ultra-high voltage flexible direct current transmission system, the method comprising the following steps: S01. Obtain the topological structure of the converter valve and establish a schematic diagram of the derivation of the reliability function of the bridge arm submodule of the converter valve; S02. Obtain historical data of the converter valve, and obtain the failure rate of the bridge arm submodule by establishing a time-varying characteristic function of the failure rate of the bridge arm submodule of the converter valve; S03. According to the reliability function derivation diagram of the converter valve and the failure rate of the bridge arm submodule, the reliability function of the converter valve is derived; S04. With the help of the transfer rate matrix of the converter valve operation state transfer process and the Markov random process model, the reliability index of the converter valve is obtained.

[0021] In the present invention, a converter valve topology structure is obtained and a converter valve reliability function derivation schematic diagram is established, which specifically includes: S101. Obtaining a converter valve topology structure; The converter valve topology of the ultra-high voltage flexible DC transmission system is the basis for establishing the converter valve reliability function derivation diagram. Figure 2 For example, the converter valve includes There are bridge arms, each of which includes n bridge arm sub-modules and 1 bridge arm reactor L.

[0022] S102. Establish a schematic diagram for deriving the reliability function of the converter valve.

[0023] Based on the topological structure of the converter valve of the ultra-high voltage flexible direct current transmission system, taking a bridge arm submodule (including IGBT valve group C1, resistor C2, capacitor C3, control and protection circuit C4 and energy extraction circuit C5) as an example, a schematic diagram for the derivation of the reliability function of the ultra-high voltage flexible direct current converter valve is established, as shown in the figure. Figure 3 shown.

[0024] In the present invention, historical data of the converter valve is obtained, and the time-varying characteristics of the failure rate of the converter valve bridge arm submodule are analyzed, which specifically includes: S201. Obtaining historical data of super-converter valve; The historical data of ultra-high voltage flexible direct current converter valves reflects the basic performance and potential design defects of each component of the converter valve, and is the basis for analyzing the time-varying characteristics of the failure rate of each component of the ultra-high voltage flexible direct current converter valve. Among them, the pre-operation information data includes technical records, installation acceptance records and drawings, etc., the operation data includes operation and maintenance data, defect data, abnormal and fault data, online monitoring data, etc., the maintenance test data includes routine test data, diagnostic test data, professional inspection record data, defect elimination data, etc., and the family defect data includes the data of defects caused by common factors such as design, material, and process of equipment of the same manufacturer, model, and batch.

[0025] S202. Analyze the time-varying characteristics of the fault rate of the converter valve bridge arm submodule.

[0026] The state of electrical equipment deteriorates over time, and the failure rate also changes accordingly. In order to obtain the time-varying characteristic curve of the failure rate of the bridge arm submodule of the converter valve, first, the entire observation period is evenly divided into s sub-intervals at a time interval T, and the number of failures of the key component bridge arm submodule in the sth sub-interval is θ r,s , the failure rate is η r，s , then η r，s The calculation formula is: , Among them, θ r,s Representative The number of failures of the bridge arm submodule Cr in each subinterval; r represents the serial number of the bridge arm submodule r∈ (1, 2, 3…5); s represents the time interval The number of subintervals that evenly divide the entire observation time, s∈(1,2,3…s); Based on the subinterval s, the failure rate η r，s Based on engineering experience, the piecewise fitting method is used to obtain the time-varying characteristic function of the bridge arm submodule failure rate: , Among them, t r，1 and t r，2 is the turning point of the failure rate of the bridge arm submodule Cr; ηr(t) is in [0, t r，1 ] is a strictly monotonically decreasing function. r，1 , t r，2 ] is approximately a constant, in [t r，2 ,+ ∞] is a strictly monotonically increasing function, so combined with engineering practice, we focus on [t r，1 , t r，2 ] interval,η r (t) in [t r，1 , t r，2 ] The failure rate in the interval is stable, so ηr is selected as the failure rate of the bridge arm submodule Cr.

[0027] In the present invention, the failure rate function relationship of the bridge arm submodule of the ultra-high voltage flexible direct current converter valve is derived, and then the converter valve reliability function is derived, which specifically includes: S301, deriving a function relationship of a converter valve bridge arm submodule failure rate; According to the derivation diagram of the converter valve reliability function, the calculation formula of the bridge arm submodule reliability function K(t) is: , Wherein, K1(t), K2(t), K3(t), K4(t), and K5(t) are the reliability functions of the IGBT valve group C1, the resistor C2, the capacitor C3, the control protection circuit C4, and the energy extraction circuit C5, respectively.

[0028] According to the actual project, the failure rate in the converter valve operation range is approximately constant, and the reliability function obeys the exponential distribution. The calculation formula of the reliability function K(t) of the bridge arm submodule can be rewritten as: , Among them, η1 represents the failure rate of the IGBT valve group C1, η2 represents the failure rate of the resistor C2, η3 represents the failure rate of the capacitor C3, η4 represents the failure rate of the control protection circuit C4, and η5 represents the failure rate of the energy extraction circuit C5.

[0029] S302. Derive the reliability function of the ultra-high voltage flexible direct current converter valve.

[0030] Configuring redundancy on each bridge arm of the converter valve can effectively improve reliability. Assume that the minimum number of bridge arm submodules required to meet the operation requirements is q. Based on the actual project, it can be seen that the topological structure of each bridge arm of the ultra-high voltage flexible direct current converter valve is the same. Therefore, taking a single bridge arm as an example, the reliability function Karm (t) of the ultra-high voltage flexible direct current converter valve is derived as follows: , Among them, n represents the total number of bridge arm submodules, and q represents the minimum required number of bridge arm submodules when the converter valve is in operation.

[0031] In the present invention, the operation state transition process of the super converter valve is considered, and the reliability index of the converter valve is solved based on the Markov random process model, which specifically includes: S401, considering the operation state transfer process of the direct current converter valve, calculating the transfer rate matrix; Combined with the actual project, it can be known that the converter valve fault is mainly in the bridge arm submodule. By defining the converter valve operation state corresponding to the number of bridge arm fault submodules, the converter valve operation state transfer process can be obtained as follows: Figure 4 In the figure, n is the total number of single bridge arm submodules, q is the minimum number of bridge arm submodules required to meet the operation requirements, and δ is the maintenance rate of the ultra-high voltage flexible direct current converter valve bridge arm.

[0032] According to the state transfer process of the converter valve, the transfer rate matrix A is obtained: A= ; S402, solve the converter valve reliability index based on the Markov random process model. Combined with the relevant knowledge of the Markov model, calculate the converter valve operating state steady-state probability index pi, , Where, i∈(0,1,2…,n-q+1); Calculate the frequency index fi of the converter valve operation status, , Among them, is the transfer rate matrix The element in the i-th row and j-th column in represents the transition rate from operating state i to operating state j (j≠i); Calculate the expected duration index of the converter valve operation state, .

[0033] refer to Figure 5 The present invention also provides a converter valve operation reliability assessment system for an ultra-high voltage flexible direct current transmission system, which implements the above-mentioned method, and the system comprises: A reliability function derivation schematic diagram building module 110 is used to obtain a converter valve topology structure and establish a converter valve reliability function derivation schematic diagram; A failure rate time-varying characteristic analysis module 120 is used to obtain historical data of the converter valve and analyze the failure rate time-varying characteristics of the converter valve bridge arm submodule; A reliability function derivation module 130, used to derive a failure rate function of a converter valve bridge arm submodule, and then derive a converter valve reliability function; The reliability index calculation module 140 is used to consider the operation state transition process of the converter valve and then solve the reliability index of the converter valve based on the Markov random process model.

[0034] The analysis of the time-varying characteristics of the failure rate of the bridge arm submodule of the ultra-high voltage flexible direct current converter valve provides a strong support for the derivation of the bridge arm submodule reliability function, the failure rate function relationship and the reliability function of the ultra-high voltage flexible direct current converter valve. The consideration of the state transition process of the ultra-high voltage flexible direct current converter valve in the reliability assessment model improves the scientificity and accuracy of the reliability assessment results of the converter valve of the ultra-high voltage flexible direct current transmission system.

[0035] Figure 6 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 5As shown, the electronic device may include: a processor (processor) 2010, a communication interface (Communications Interface) 2020, a memory (memory) 2030 and a communication bus 2040, wherein the processor 2010, the communication interface 2020, and the memory 2030 communicate with each other through the communication bus 2040. The processor 2010 may call the logic instructions in the memory 2030 to execute the above method.

[0036] In addition, the logic instructions in the above-mentioned memory 2030 can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, 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, and the computer software product is stored in a storage medium, including 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 invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0037] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can perform the steps of the above methods.

[0038] In another aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is implemented to perform the steps of the above methods when executed by a processor. Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for evaluating the operation reliability of converter valves in an ultra-high voltage flexible direct current transmission system, characterized in that: The method comprises the following steps: S01. Obtain the topological structure of the converter valve and establish a schematic diagram of the derivation of the reliability function of the bridge arm submodule of the converter valve; S02. Obtain historical data of the converter valve, and obtain the failure rate of the bridge arm submodule by establishing a time-varying characteristic function of the failure rate of the bridge arm submodule of the converter valve; S03. According to the reliability function derivation diagram of the converter valve and the failure rate of the bridge arm submodule, the reliability function of the converter valve is derived; S04. With the help of the transfer rate matrix of the converter valve operation state transfer process and the Markov random process model, the reliability index of the converter valve is obtained.

2. The method for evaluating the operation reliability of a converter valve according to claim 1, characterized in that: The valve topology structure includes m bridge arms, each bridge arm includes n bridge arm submodules and 1 bridge arm reactance L; The schematic diagram for deriving the reliability function of the bridge arm submodule includes an IGBT valve group C1, a resistor C2, a capacitor C3, a control protection circuit C4 and an energy extraction circuit C5.

3. The method for evaluating the operation reliability of a converter valve according to claim 1, characterized in that: The historical data of the converter valve includes: information data before the converter valve operation, converter valve operation data, converter valve maintenance data, and converter valve family defect data.

4. The method for evaluating the operation reliability of a converter valve according to claim 1, characterized in that: The process of establishing the time-varying characteristic function of the fault rate of the bridge arm submodule of the converter valve includes: First, establish the failure rate formula η of the bridge arm submodule r，s for, ， Among them, θ r,s Representative The number of failures of the bridge arm submodule Cr in each subinterval; r represents the serial number of the bridge arm submodule r∈ (1, 2, 3…5); s represents the time interval The number of subintervals that evenly divide the entire observation time, s∈(1,2,3…s); Then, based on the subinterval s and the failure rate η r，s Based on engineering experience, the segmented fitting method is used to obtain the time-varying characteristic function ηr(t) of the failure rate of the bridge arm submodule Cr. ， Among them, t r，1 and t r，2 is the turning point of the failure rate of the bridge arm submodule Cr; ηr(t) is in [0, t r，1 ] is a strictly monotonically decreasing function. r，1 , t r，2 ] is approximately a constant, in [t r，2 ,+∞] is a strictly monotonically increasing function, so η r (t) in [t r，1 ,t r，2 ] The failure rate in the interval is stable, so ηr is selected as the failure rate of the bridge arm submodule Cr.

5. The method for evaluating the operation reliability of a converter valve according to claim 1, characterized in that: The derivation process of the converter valve reliability function includes: First, the reliability function K(t) of the bridge arm submodule Cr is established. ， Among them, η1 represents the failure rate of the IGBT valve group C1, η2 represents the failure rate of the resistor C2, η3 represents the failure rate of the capacitor C3, η4 represents the failure rate of the control protection circuit C4, and η5 represents the failure rate of the energy extraction circuit C5; Then, since the topological structure of a single bridge arm is the same, the reliability function Karm(t) of the converter valve is: ， Among them, n represents the total number of bridge arm submodules, and q represents the minimum required number of bridge arm submodules when the converter valve is in operation.

6. The method for evaluating the operation reliability of a converter valve according to claim 1, characterized in that: The transfer rate matrix is: A = ， Among them, δ is the maintenance rate of the ultra-high voltage flexible direct current converter valve bridge arm, q represents the minimum required number of bridge arm submodules when the converter valve is in operation, and n represents the total number of bridge arm submodules; Based on the Markov random process model, the reliability index of the converter valve is obtained: The steady-state probability index pi of the converter valve operation state, ， Where, i∈(0,1,2…,n-q+1); Frequency index fi of converter valve operation status, ， Among them, is the transfer rate matrix The element in the i-th row and j-th column in represents the transition rate from operating state i to operating state j (j≠i); Expected indicators of converter valve operation duration , 。 7. A converter valve operation reliability assessment system for an ultra-high voltage flexible direct current transmission system, implementing the method described in any one of claims 1 to 6, characterized in that: The system comprises: A reliability function derivation schematic diagram construction module is used to obtain a converter valve topology structure and establish a converter valve reliability function derivation schematic diagram; A failure rate time-varying characteristic analysis module is used to obtain historical data of the converter valve and analyze the failure rate time-varying characteristics of the converter valve bridge arm submodule; A reliability function derivation module is used to derive a failure rate function of a converter valve bridge arm submodule, and then derive a converter valve reliability function; The reliability index calculation module is used to consider the operation state transition process of the converter valve and then solve the reliability index of the converter valve based on the Markov random process model.

8. An electronic device, comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A non-transitory computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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