Method and device for monitoring capacitor degradation of a flexible direct current transmission converter valve sub-module

Abstract

The application provides a flexible direct current transmission converter valve submodule capacitor attenuation monitoring method and device, relates to the field of power equipment maintenance, and comprises the following steps: determining a switching frequency change curve according to the cumulative switching times of each bridge arm submodule; constructing an attenuation monitoring target matrix according to the switching frequency change curve; and determining the converter valve submodule with capacitor attenuation according to the attenuation monitoring target matrix. The application can recognize the capacitor capacity value reduction trend of the flexible direct current transmission converter valve submodule through the short-time submodule switching frequency change characteristics, support the operation monitoring and maintenance of the converter valve support capacitor, and further ensure the stable operation of the flexible direct current transmission project.

Description

Technical Field

[0001] This application relates to the field of power equipment maintenance, specifically a method and device for monitoring capacitance attenuation in a flexible DC transmission converter valve submodule. Background Technology

[0002] Flexible direct current (DC) transmission technology, as one of the important technical means for constructing new power systems, has led to the establishment of numerous DC transmission projects. Compared with traditional conventional DC transmission technology, the advantages of flexible DC transmission technology lie in its converter valves, which offer flexible control methods and possess excellent scalability and power output quality. The key components of the converter valves mainly include power electronic devices and metallized film capacitors. While metallized film capacitors can self-heal after breakdown during operation, thus ensuring the reliable operation of submodules, their capacitance gradually decreases with each breakdown, accompanied by deterioration of various performance indicators, posing potential risks to the operation of the flexible DC converter valves and converter stations.

[0003] Currently, capacitor failures in converter valve submodules mainly focus on two types of instantaneous faults: short circuits and open circuits. However, research on their long-term failure processes and aging mechanisms is limited. Existing methods for identifying capacitor aging in converter valve submodules are primarily offline detection methods. For example, one method for detecting capacitor aging in MMC submodules compares a target submodule with a reference submodule and detects capacitor aging based on the proportion of high-frequency components and the proportion of voltage change after wavelet packet decomposition. Summary of the Invention

[0004] To address the problems in the prior art, this application provides a method and device for monitoring the capacitance attenuation of a flexible DC transmission converter valve submodule. This method can identify the decreasing trend of the capacitance value of the flexible DC transmission converter valve submodule by observing the short-term switching frequency variation characteristics of the submodule, thereby supporting the operation monitoring and maintenance of the converter valve support capacitor and ensuring the stable operation of the flexible DC transmission project.

[0005] To solve the above-mentioned technical problems, this application provides the following technical solution:

[0006] In a first aspect, this application provides a method for monitoring capacitance attenuation in a flexible DC transmission converter valve submodule, comprising:

[0007] The change curve of the number of switching operations is determined based on the cumulative number of switching operations for each bridge arm sub-module.

[0008] Construct an attenuation monitoring target matrix based on the change curve of the number of switching operations;

[0009] The converter valve submodule with capacitance attenuation is determined based on the attenuation monitoring target matrix.

[0010] Further, determining the switching frequency change curve based on the cumulative switching frequency of each bridge arm submodule includes:

[0011] The cumulative number of switching operations for each bridge arm submodule is obtained according to a preset time interval.

[0012] The cumulative number of switching operations for each bridge arm submodule within a preset time period is determined based on the cumulative number of switching operations for each bridge arm submodule, and the switching operation number change curve is generated.

[0013] Furthermore, the step of constructing the attenuation monitoring target matrix based on the change curve of the number of switching operations includes:

[0014] Determine the Hausdorff distance between the switching frequency variation curves corresponding to each bridge arm submodule;

[0015] Determine the maximum and average Hausdorf distances for each bridge arm submodule;

[0016] The attenuation monitoring target matrix is ​​constructed based on the maximum value and the average value.

[0017] Further, the step of determining the converter valve submodule with capacitance attenuation based on the attenuation monitoring target matrix includes:

[0018] Select the sub-module pairs that appear in the attenuation monitoring target matrix, and calculate the maximum value of the Hausdorf distance between the switching number curves corresponding to the two sub-modules in the sub-module pair;

[0019] Based on the maximum value of the corresponding submodule, the converter valve submodule with capacitance decay is determined.

[0020] Secondly, this application provides a capacitor attenuation monitoring device for a flexible DC transmission converter valve submodule, comprising:

[0021] The change curve determination unit is used to determine the change curve of the number of switching based on the cumulative number of switching of each bridge arm sub-module.

[0022] The target matrix construction unit is used to construct an attenuation monitoring target matrix based on the change curve of the number of switching operations.

[0023] The capacitor attenuation determination unit is used to determine the converter valve submodules that exhibit capacitor attenuation based on the attenuation monitoring target matrix.

[0024] Furthermore, the change curve determination unit includes:

[0025] The switching count acquisition module is used to acquire the cumulative switching count of each bridge arm submodule according to a preset time interval;

[0026] The change curve generation module is used to determine the cumulative number of times each bridge arm submodule is switched over a preset time based on the cumulative number of switching times of each bridge arm submodule, and generate the change curve of the number of switching times.

[0027] Furthermore, the target matrix construction unit includes:

[0028] The distance determination module is used to determine the Hausdorf distance between the switching frequency variation curves corresponding to each bridge arm submodule;

[0029] The maximum and minimum value determination module is used to determine the maximum and average values ​​of Hausdorf distances corresponding to each bridge arm submodule;

[0030] The target matrix construction module is used to construct the attenuation monitoring target matrix based on the maximum value and the average value.

[0031] Furthermore, the capacitance attenuation determination unit includes:

[0032] The extreme value determination module is used to select the sub-module pairs appearing in the attenuation monitoring target matrix and calculate the maximum value of the Hausdorf distance between the switching number curves corresponding to the two sub-modules in the sub-module pair;

[0033] The capacitor attenuation screening module is used to determine the converter valve sub-modules that exhibit capacitor attenuation based on the maximum value of the corresponding sub-module.

[0034] Thirdly, this application provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the flexible DC transmission converter valve submodule capacitance attenuation monitoring method.

[0035] Fourthly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the flexible DC transmission converter valve submodule capacitance attenuation monitoring method.

[0036] Fifthly, this application provides a computer program product, including a computer program / instructions, which, when executed by a processor, implement the steps of the flexible DC transmission converter valve submodule capacitance attenuation monitoring method.

[0037] To address the problems in existing technologies, this application provides a method and device for monitoring the capacitance attenuation of flexible DC transmission converter valve submodules. This method can acquire the cumulative switching frequency of each bridge arm submodule over a short period, and utilize Hausdorff distance to analyze the similarity of the switching frequency variation patterns of each bridge arm submodule. This allows for the identification of submodules with relatively frequent switching that may exhibit capacitance attenuation, thus providing a reference for the operation and maintenance of flexible DC converter valve equipment. Compared to existing methods for identifying capacitor attenuation and aging in converter valve submodules, this application can accurately identify and locate the attenuation of the DC support capacitors of each bridge arm submodule in a flexible DC converter valve. It does not rely on excessively high sampling frequencies or data storage and processing resources, making it widely applicable. Furthermore, it does not require additional online monitoring devices, offering good economic efficiency. It can be integrated into advanced application systems such as digital platform online monitoring, fault early warning, and condition assessment, demonstrating high potential for widespread application. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a flowchart of the capacitor attenuation monitoring method for the flexible DC transmission converter valve submodule in this application embodiment;

[0040] Figure 2 This is a flowchart illustrating the process of determining the change curve of the number of cutting operations in this application embodiment;

[0041] Figure 3 This is a flowchart illustrating the construction of the attenuation monitoring target matrix in this application embodiment;

[0042] Figure 4 This is a flowchart illustrating the process of determining the converter valve submodule exhibiting capacitance decay in this application embodiment;

[0043] Figure 5 This is a structural diagram of the capacitor attenuation monitoring device for the flexible DC transmission converter valve submodule in this embodiment of the application.

[0044] Figure 6 This is a structural diagram of the change curve determination unit in an embodiment of this application;

[0045] Figure 7 This is a structural diagram of the target matrix construction unit in the embodiments of this application;

[0046] Figure 8 This is a structural diagram of the capacitor attenuation determination unit in an embodiment of this application;

[0047] Figure 9 This is a schematic diagram showing the statistics of the number of times the converter valve submodule is switched on and off under normal circumstances in an embodiment of this application;

[0048] Figure 10 This is a schematic diagram of the capacitor attenuation monitoring method for the flexible DC transmission converter valve submodule in this application embodiment;

[0049] Figure 11 This is a schematic diagram showing the statistics of the number of switching operations of each submodule after the capacitor of the converter valve submodule has aged in the embodiments of this application;

[0050] Figure 12 This is a schematic diagram of the structure of the electronic device in the embodiments of this application. Detailed Implementation

[0051] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0052] The acquisition, storage, use, and processing of data in this application comply with relevant laws and regulations.

[0053] In one embodiment, see Figure 1 In order to identify the decreasing trend of capacitor value in flexible DC transmission converter valve submodules by analyzing short-term submodule switching frequency variations, and to support the operation monitoring and maintenance of the converter valve support capacitors, thereby ensuring the stable operation of flexible DC transmission projects, this application provides a method for monitoring capacitor attenuation in flexible DC transmission converter valve submodules, including:

[0054] S101: Determine the switching frequency change curve based on the cumulative switching frequency of each bridge arm sub-module;

[0055] S102: Construct an attenuation monitoring target matrix based on the change curve of the number of switching operations;

[0056] S103: Determine the converter valve submodule with capacitance attenuation based on the attenuation monitoring target matrix.

[0057] It is understood that the flexible DC transmission converter valve submodule capacitor attenuation identification method provided in this application identifies the decreasing trend of the capacitor value of the flexible DC transmission converter valve submodule by acquiring the characteristics of the short-term switching frequency change of the converter valve submodule, supports the operation monitoring and maintenance of the converter valve support capacitor, and thus ensures the stable operation of the flexible DC transmission project.

[0058] To address the issue of capacitor status assessment in flexible DC transmission converter valve submodules, this application provides an online monitoring method for capacitor attenuation in flexible DC transmission converter valve submodules. The basic principle is as follows:

[0059] See Figure 9 , Figure 9 This section presents statistics on the number of switching operations of the converter valve submodule (hereinafter referred to as "submodule") under normal operating conditions (without faults). Assuming the time interval of the converter valve control system is Δt, the sampling time interval of the online monitoring system is also Δt. The statistical analysis focuses on the number of switching operations N of each submodule in the upper and lower arms of the three commutation units of the converter valve within a statistical time window T = 10 seconds. mnp Where m = a, b, c represent the three commutation units a, b, c, n = u, l represent the upper and lower bridge arms, and p represents the submodule number within each bridge arm.

[0060] The monitoring cycle time interval is ΔT. Each time, the curve of the cumulative number of switches of each submodule changing over time within T is recorded and denoted as L. mnp Solve for the Hausdorff distance H between the curves. mnp-q Where p and q are the submodule numbers corresponding to the two target curves (p = 1, 2, ..., K; q = 1, 2, ..., K; K is the total number of bridge arm submodules). Under normal operating conditions, the converter valve submodule switching strategy controls each submodule to avoid frequent switching. Therefore, the trend of the cumulative number of switching times of each submodule changes very little over time, and the H curves of the cumulative number of switching times of each submodule are similar. mnp_q At a low level, the positions of each curve remain within a certain range, such as Figure 1 As shown, SM (sub-module) represents a sub-module, and the total number of sub-modules K in a single bridge arm in the example is 30.

[0061] When the capacitors in one or more submodules show signs of aging, the capacitance values ​​decrease to varying degrees, resulting in a decrease in the charging and discharging time and an increase in the switching frequency of the corresponding submodule. This leads to an increase in the cumulative switching count curve L for the capacitor-aged submodule. mnp Gradually deviating from the curve range corresponding to the normal submodule, i.e., H mnp-q If the trend shows an upward trend, then the following process for the capacitor attenuation identification method in the sub-module is as follows.

[0062] Specifically, the steps of the online identification method for submodule capacitor attenuation are as follows:

[0063] The activation criterion of this method is shown in (1). When a certain submodule H in the m-phase n-arm bridge... mnp-q The maximum value H mnp-q_max All submodules H of the n-phase bridge arm greater than m phase mnp-q_maxThe average value of the results H mn_ave When the capacitor aging of the subsequent sub-module is detected and located, k is the sensitivity coefficient of the start-up criterion, which is generally taken as 1.1 to 1.3.

[0064] H mnp-q_max >kH mn_ave (1)

[0065] Take H in the bridge arm mnp_q The top K / Q largest values ​​in the results are used as elements of the target matrix, where Q is the submodule capacitor attenuation screening and adjustment coefficient, which can be adjusted according to the number of converter valve submodules and the data processing capability of the monitoring and analysis system in the actual project. The target matrix is ​​as follows:

[0066] F mn =[H mnp-q_max1 H mnp-q_max2 … H mnp-q_maxK / Q (2)

[0067] Based on the two submodule numbers corresponding to the elements of the matrix given in (2), statistics are performed, and the submodule numbers that appear are processed a second time, that is, the H values ​​between the cumulative curves of the switching of the submodules with the above numbers are compared again. mnp-q_max If H mnp-q_max Still exceeds the entire bridge arm submodule H mnp-q_max If the average value is 0, it indicates that the capacitor of the submodule is degraded.

[0068] As described above, the flexible DC-DC converter valve submodule capacitor attenuation monitoring method provided in this application can obtain the cumulative switching frequency of each bridge arm submodule over a short period of time. By using Hausdorff distance to analyze the similarity of the switching frequency variation patterns of each bridge arm submodule, it can identify the possibility of capacitor attenuation in submodules with relatively frequent switching, thus providing a reference for the operation and maintenance of flexible DC-DC converter valve equipment. Compared with existing methods for identifying capacitor attenuation and aging in converter valve submodules, this application can accurately identify and locate the attenuation of the DC support capacitor of each bridge arm submodule in the flexible DC-DC converter valve. It does not rely on excessively high sampling frequencies and data storage and processing resources, has wide applicability, and does not require additional online monitoring devices, thus offering good economic efficiency. Furthermore, it can be integrated into advanced application systems such as online monitoring and fault early warning, and condition assessment on digital platforms, making it highly valuable for widespread application.

[0069] The following provides a detailed explanation of steps S101 to S103.

[0070] In one embodiment, see Figure 2 The step of determining the switching frequency change curve based on the cumulative switching frequency of each bridge arm submodule includes:

[0071] S201: Obtain the cumulative number of switching operations for each bridge arm submodule according to a preset time interval;

[0072] S202: Determine the cumulative number of switching operations for each bridge arm submodule over a preset time period based on the cumulative number of switching operations for each bridge arm submodule, and generate the switching operation number change curve.

[0073] It is understandable that the online monitoring system performs a check every ΔT interval. Figure 10 The data extraction and processing flow is as follows: Based on the switching command signal of the submodule issued by the converter valve control system or other signals that can characterize the voltage / current changes during the switching process of the submodule, the cumulative number of switching times and the corresponding time of each submodule of each arm within the monitoring time window T are collected, and the sampling time interval is Δt.

[0074] Based on the information collected in the previous step, a curve L is generated showing the cumulative number of switching operations for each submodule over time within T. mnp Where m = a, b, c correspond to three commutation units, n = u, l represent the upper and lower bridge arms, and p represents the submodule number within each bridge arm.

[0075] As can be seen from the above description, the flexible DC transmission converter valve submodule capacitor attenuation monitoring method provided in this application can determine the switching frequency change curve based on the cumulative switching frequency of each bridge arm submodule.

[0076] In one embodiment, see Figure 3 The step of constructing the attenuation monitoring target matrix based on the change curve of the number of switching operations includes:

[0077] S301: Determine the Hausdorff distance between the switching frequency variation curves corresponding to each bridge arm submodule;

[0078] S302: Determine the maximum and average Hausdorf distances corresponding to each bridge arm submodule;

[0079] S303: Construct the attenuation monitoring target matrix based on the maximum value and the average value.

[0080] Understandably, see Figure 10 Based on the cumulative number of switching operations for each submodule obtained in the previous step, calculate the L curves. mnp The Hausdorff distance between them is denoted as H. mnp-q , where p and q are both submodule numbers.

[0081] Next, calculate H within each bridge arm. mnp-q The maximum value H mnp-qmax and average value H mn_ave H mnp-qmaxH represents the similarity of the trend of the number of cuts between submodules p and q within T. mn_ave The average level of similarity in the number of switching operations of each submodule within the m-phase n-arm bridge reflects the overall trend of submodule switching within that arm.

[0082] Furthermore, based on H calculated in the previous step mn_ave H mnp-qmax Determine whether to execute subsequent data processing steps, i.e., when H mnp-qmax >kH mn_ave If necessary, continue with the subsequent data processing steps; otherwise, return to the initial steps to sample data for the next monitoring cycle.

[0083] Finally, select H within the m-phase n-arm bridge. mnp-qmax The largest K / Q is used as the target matrix F mn Where K is the total number of bridge arm sub-modules, and Q is the sub-module capacitor attenuation screening and adjustment coefficient, which can be adjusted according to the number of converter valve sub-modules and the data processing capability of the monitoring and analysis system in the actual project.

[0084] As can be seen from the above description, the flexible DC transmission converter valve submodule capacitor attenuation monitoring method provided in this application can construct an attenuation monitoring target matrix based on the switching frequency change curve.

[0085] In one embodiment, see Figure 4 The step of determining the converter valve submodule with capacitance attenuation based on the attenuation monitoring target matrix includes:

[0086] S401: Select the sub-module pairs that appear in the attenuation monitoring target matrix, and calculate the maximum value of the Hausdorf distance between the switching number curves corresponding to the two sub-modules in the sub-module pair;

[0087] S402: Determine the converter valve submodule with capacitance decay based on the corresponding maximum value of the submodule.

[0088] Understandably, see Figure 10 Select the target matrix F mn The submodule numbers appearing in the data are used to calculate the H-value between the curves of the number of submodule switching attempts after filtering. mnp-qmax The judgment is made based on the calculation results of the previous step, that is, when H... mnp-qmax <H mn_ave Then, the corresponding two sub-modules can be excluded. After successively judging each one, the remaining sub-module numbers are the sub-module numbers of capacitor attenuation; if the calculation results all satisfy H mnp-qmax >H mn_ave Then F mn The submodule numbers appearing in the text are all submodule numbers related to capacitor attenuation.

[0089] To better illustrate the method provided in this application, a specific embodiment is given below.

[0090] See Figure 11 , Figure 11 This is a statistical analysis of the number of switching operations of each submodule after the capacitors of the converter valve submodule have aged.

[0091] Taking the upper bridge arm of phase a of the converter valve as an example, the number of submodules in a single bridge arm is K=30. Figure 11 The statistics of the number of switching operations for each submodule in the entire bridge arm after the capacitance values ​​of submodules 1, 14, and 21 decreased are given. The submodule capacitance attenuation screening and adjustment coefficient Q is tentatively set to 6. Therefore, the target matrix contains 5 elements, and the calculation results are as follows:

[0092] F au =[H au1-7_max1 (475)H au1-23_max2 (468)H au21-7_max3 (401)H au21-23_max4 (394)H au14-7_max5 (260)](3)

[0093] According to the target matrix results in (3), submodule numbers 1, 7, 14, 21, and 23 appeared. The results of the secondary processing are as follows:

[0094] H au1-7_max =475, H au1-14_max =215, H au1-21_max =74, H au1-23_max =468, H au7-1_max =475, H au7-14_max =260, H au7-21_max =401, H au7-23_max =7,H au14-1_max =215, H au14-7_max =260, H au14-21_max =141, H au14-23_max =253,H au21-23_max =394, H au23-1_max =468, H au23-7_max =7,H au23-14_max =253,H au23-21_max =394.

[0095] Based on the above results, H au7-23_max =7 is less than H aup-q_max The average value (8.89) indicates that the capacitors of submodules 7 and 23 are in a normal state, which means that the capacitors of submodules 1, 14, and 21 are attenuated.

[0096] Based on the same inventive concept, this application also provides a flexible DC transmission converter valve submodule capacitor attenuation monitoring device, which can be used to implement the method described in the above embodiments, as described in the following embodiments. Since the principle of the flexible DC transmission converter valve submodule capacitor attenuation monitoring device in solving the problem is similar to that of the flexible DC transmission converter valve submodule capacitor attenuation monitoring method, the implementation of the flexible DC transmission converter valve submodule capacitor attenuation monitoring device can refer to the implementation of the software performance benchmark determination method, and repeated details will not be elaborated further. As used below, the terms "unit" or "module" can refer to a combination of software and / or hardware that implements a predetermined function. Although the system described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0097] In one embodiment, see Figure 5 In order to identify the decreasing trend of capacitor value in flexible DC transmission converter valve submodules by analyzing the short-term switching frequency variation characteristics of submodules, and to support the operation monitoring and maintenance of the converter valve support capacitors, thereby ensuring the stable operation of flexible DC transmission projects, this application provides a flexible DC transmission converter valve submodule capacitor attenuation monitoring device, comprising:

[0098] The variation curve determination unit 501 is used to determine the variation curve of the number of switching based on the cumulative number of switching of each bridge arm sub-module.

[0099] The target matrix construction unit 502 is used to construct an attenuation monitoring target matrix based on the switching frequency change curve.

[0100] The capacitor attenuation determination unit 503 is used to determine the converter valve submodule with capacitor attenuation based on the attenuation monitoring target matrix.

[0101] In one embodiment, see Figure 6 The change curve determination unit 501 includes:

[0102] The switching count acquisition module 601 is used to acquire the cumulative switching count of each bridge arm submodule according to a preset time interval;

[0103] The change curve generation module 602 is used to determine the cumulative number of times each bridge arm submodule is switched over a preset time based on the cumulative number of switching times of each bridge arm submodule, and generate the change curve of the number of switching times.

[0104] In one embodiment, see Figure 7 The target matrix construction unit 502 includes:

[0105] The distance determination module 701 is used to determine the Hausdorf distance between the switching frequency variation curves corresponding to each bridge arm submodule;

[0106] The maximum and minimum value determination module 702 is used to determine the maximum and average values ​​of Hausdorf distances corresponding to each bridge arm sub-module;

[0107] The target matrix construction module 703 is used to construct the attenuation monitoring target matrix based on the maximum value and the average value.

[0108] In one embodiment, see Figure 8 The capacitance attenuation determination unit 503 includes:

[0109] The extreme value determination module 801 is used to select the sub-module pairs appearing in the attenuation monitoring target matrix and calculate the maximum value of the Hausdorf distance between the switching number curves corresponding to the two sub-modules in the sub-module pair;

[0110] The capacitor attenuation screening module 802 is used to determine the converter valve sub-module with capacitor attenuation based on the maximum value of the corresponding sub-module.

[0111] From a hardware perspective, in order to identify the decreasing trend of the capacitor value of the flexible DC transmission converter valve submodule by observing the short-term switching frequency variation characteristics of the submodule, and to support the operation monitoring and maintenance of the converter valve support capacitor, thereby ensuring the stable operation of the flexible DC transmission project, this application provides an embodiment of an electronic device for implementing all or part of the aforementioned flexible DC transmission converter valve submodule capacitor attenuation monitoring method. The electronic device specifically includes the following components:

[0112] The system comprises a processor, a memory, a communications interface, and a bus; wherein the processor, memory, and communications interface communicate with each other via the bus; the communications interface is used to realize information transmission between the flexible DC transmission converter valve submodule capacitance attenuation monitoring device and core business systems, user terminals, and related databases and other related equipment; the logic controller can be a desktop computer, tablet computer, or mobile terminal, etc., and this embodiment is not limited to these. In this embodiment, the logic controller can be implemented with reference to the embodiments of the flexible DC transmission converter valve submodule capacitance attenuation monitoring method and the flexible DC transmission converter valve submodule capacitance attenuation monitoring device in the embodiments, the contents of which are incorporated herein, and repeated details will not be described again.

[0113] It is understood that the user terminal may include smartphones, tablet computers, network set-top boxes, portable computers, desktop computers, personal digital assistants (PDAs), in-vehicle devices, smart wearable devices, etc. Among these, the smart wearable devices may include smart glasses, smartwatches, smart bracelets, etc.

[0114] In practical applications, part of the capacitance attenuation monitoring method for the flexible DC transmission converter valve submodule can be executed on the electronic device side as described above, or all operations can be completed in the client device. The choice can be made based on the processing power of the client device and the limitations of the user's usage scenario. This application does not impose any limitations on this. If all operations are completed in the client device, the client device may further include a processor.

[0115] The aforementioned client device may have a communication module (i.e., a communication unit) that can communicate with a remote server to achieve data transmission. The server may include a server on the task scheduling center side; in other implementation scenarios, it may also include a server on an intermediate platform, such as a server on a third-party server platform that has a communication link with the task scheduling center server. The server may include a single computer device, a server cluster consisting of multiple servers, or a distributed server structure.

[0116] Figure 12 This is a schematic block diagram illustrating the system configuration of the electronic device 9600 according to an embodiment of this application. Figure 12 As shown, the electronic device 9600 may include a central processing unit 9100 and a memory 9140; the memory 9140 is coupled to the central processing unit 9100. It is worth noting that... Figure 12 This is an example; other types of structures can also be used to supplement or replace this structure to achieve telecommunications functions or other functions.

[0117] In one embodiment, the capacitance attenuation monitoring method for the flexible DC transmission converter valve submodule can be integrated into the central processing unit 9100. The central processing unit 9100 can be configured to perform the following control:

[0118] S101: Determine the switching frequency change curve based on the cumulative switching frequency of each bridge arm sub-module;

[0119] S102: Construct an attenuation monitoring target matrix based on the change curve of the number of switching operations;

[0120] S103: Determine the converter valve submodule with capacitance attenuation based on the attenuation monitoring target matrix.

[0121] As described above, the flexible DC transmission converter valve submodule capacitor attenuation monitoring method and device provided in this application can obtain the cumulative switching frequency of each bridge arm submodule over a short period of time. By using Hausdorff distance to analyze the similarity of the switching frequency variation patterns of each bridge arm submodule, it can identify the possibility of capacitor attenuation in submodules with relatively frequent switching, thus providing a reference for the operation and maintenance of flexible DC converter valve equipment. Compared with existing methods for identifying capacitor attenuation and aging of converter valve submodules, this application can accurately identify and locate the attenuation of the DC support capacitor of each bridge arm submodule of the flexible DC converter valve. It does not rely on excessively high sampling frequencies and data storage and processing resources, has wide applicability, and does not require additional online monitoring devices, thus offering good economic efficiency. Furthermore, it can be integrated into advanced application systems such as digital platform online monitoring, fault early warning, and condition assessment, making it highly valuable for widespread application.

[0122] In another embodiment, the capacitor attenuation monitoring device for the flexible DC transmission converter valve submodule can be configured separately from the central processing unit 9100. For example, the capacitor attenuation monitoring device for the flexible DC transmission converter valve submodule can be configured as a chip connected to the central processing unit 9100, and the function of the capacitor attenuation monitoring method for the flexible DC transmission converter valve submodule can be realized through the control of the central processing unit.

[0123] like Figure 12 As shown, the electronic device 9600 may further include: a communication module 9110, an input unit 9120, an audio processor 9130, a display 9160, and a power supply 9170. It is worth noting that the electronic device 9600 does not necessarily need to include these components. Figure 12 All components shown; in addition, the electronic device 9600 may also include Figure 12 For components not shown, please refer to existing technologies.

[0124] like Figure 12 As shown, the central processing unit 9100, sometimes also referred to as a controller or operating control, may include a microprocessor or other processor device and / or logic device, which receives inputs and controls the operation of various components of the electronic device 9600.

[0125] The memory 9140 may be, for example, one or more of a cache, flash memory, hard drive, removable media, volatile memory, non-volatile memory, or other suitable devices. It may store the aforementioned failure-related information, and also store a program for executing that information. The central processing unit 9100 may execute the program stored in the memory 9140 to perform information storage or processing, etc.

[0126] Input unit 9120 provides input to central processing unit 9100. Input unit 9120 may be, for example, a keypad or touch input device. Power supply 9170 provides power to electronic device 9600. Display 9160 displays images and text. Display may be, for example, an LCD display, but is not limited thereto.

[0127] The memory 9140 can be a solid-state memory, such as a read-only memory (ROM), random access memory (RAM), a SIM card, etc. It can also be a memory that retains information even when power is off, can be selectively erased, and contains more data; examples of this type of memory are sometimes referred to as EPROMs. The memory 9140 can also be some other type of device. The memory 9140 includes a buffer memory 9141 (sometimes referred to as a buffer). The memory 9140 may include an application / function storage unit 9142 for storing application programs and function programs or processes for executing the operation of the electronic device 9600 via the central processing unit 9100.

[0128] The memory 9140 may also include a data storage unit 9143 for storing data, such as contacts, digital data, pictures, sounds, and / or any other data used by the electronic device. The driver storage unit 9144 of the memory 9140 may include various drivers for the electronic device's communication functions and / or for performing other functions of the electronic device (such as messaging applications, address book applications, etc.).

[0129] The communication module 9110 is a transmitter / receiver 9110 that transmits and receives signals via the antenna 9111. The communication module (transmitter / receiver) 9110 is coupled to the central processing unit 9100 to provide input signals and receive output signals, which can be the same as in a conventional mobile communication terminal.

[0130] Based on different communication technologies, multiple communication modules 9110 can be configured in the same electronic device, such as cellular network modules, Bluetooth modules, and / or wireless LAN modules. The communication module (transmitter / receiver) 9110 is also coupled to a speaker 9131 and a microphone 9132 via an audio processor 9130 to provide audio output via the speaker 9131 and receive audio input from the microphone 9132, thereby realizing typical telecommunications functions. The audio processor 9130 may include any suitable buffer, decoder, amplifier, etc. Additionally, the audio processor 9130 is also coupled to a central processing unit 9100, enabling on-device recording via the microphone 9132 and on-device playback of stored sound via the speaker 9131.

[0131] Embodiments of this application also provide a computer-readable storage medium capable of implementing all steps of the flexible DC transmission converter valve submodule capacitance attenuation monitoring method with a server or client execution subject as described in the above embodiments. The computer-readable storage medium stores a computer program that, when executed by a processor, implements all steps of the flexible DC transmission converter valve submodule capacitance attenuation monitoring method with a server or client execution subject as described in the above embodiments. For example, when the processor executes the computer program, it implements the following steps:

[0132] S101: Determine the switching frequency change curve based on the cumulative switching frequency of each bridge arm sub-module;

[0133] S102: Construct an attenuation monitoring target matrix based on the change curve of the number of switching operations;

[0134] S103: Determine the converter valve submodule with capacitance attenuation based on the attenuation monitoring target matrix.

[0135] As described above, the flexible DC transmission converter valve submodule capacitor attenuation monitoring method and device provided in this application can obtain the cumulative switching frequency of each bridge arm submodule over a short period of time. By using Hausdorff distance to analyze the similarity of the switching frequency variation patterns of each bridge arm submodule, it can identify the possibility of capacitor attenuation in submodules with relatively frequent switching, thus providing a reference for the operation and maintenance of flexible DC converter valve equipment. Compared with existing methods for identifying capacitor attenuation and aging of converter valve submodules, this application can accurately identify and locate the attenuation of the DC support capacitor of each bridge arm submodule of the flexible DC converter valve. It does not rely on excessively high sampling frequencies and data storage and processing resources, has wide applicability, and does not require additional online monitoring devices, thus offering good economic efficiency. Furthermore, it can be integrated into advanced application systems such as digital platform online monitoring, fault early warning, and condition assessment, making it highly valuable for widespread application.

[0136] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, apparatus, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0137] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (devices), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0138] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0139] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0140] Specific embodiments have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A method for monitoring capacitance attenuation in a flexible DC transmission converter valve submodule, characterized in that, include: The change curve of the number of switching operations is determined based on the cumulative number of switching operations for each bridge arm sub-module. Construct an attenuation monitoring target matrix based on the change curve of the number of switching operations; The converter valve submodule with capacitance attenuation is determined based on the attenuation monitoring target matrix; The step of constructing the attenuation monitoring target matrix based on the change curve of the number of switching operations includes: Determine the Hausdorff distance between the switching frequency variation curves corresponding to each bridge arm submodule; Determine the maximum and average Hausdorf distances corresponding to each bridge arm submodule; The attenuation monitoring target matrix is ​​constructed based on the maximum value and the average value. The step of determining the converter valve submodule with capacitance attenuation based on the attenuation monitoring target matrix includes: Select the sub-module pairs that appear in the attenuation monitoring target matrix, and calculate the maximum value of the Hausdorf distance between the switching number curves corresponding to the two sub-modules in the sub-module pair; Based on the maximum value of the corresponding submodule, determine the converter valve submodule that has capacitance decay; Specifically, the submodule numbers appearing in the attenuation monitoring target matrix are selected, and the maximum value of the Hausdorff distance between the switching curves of the submodules after screening is calculated. If the maximum value of the Hausdorff distance is less than the average value of the Hausdorff distance, the corresponding two submodules are excluded. The remaining submodule numbers after sequential discrimination are the submodule numbers of capacitor attenuation. If the calculation results all satisfy the condition that the maximum value of the Hausdorff distance is greater than the average value of the Hausdorff distance, then the submodule numbers appearing in the attenuation monitoring target matrix are all submodule numbers of capacitor attenuation.

2. The method for monitoring capacitance attenuation of flexible DC transmission converter valve submodules according to claim 1, wherein the step of determining the switching frequency change curve based on the acquired cumulative switching frequency of each bridge arm submodule is characterized in that, include: The cumulative number of switching operations for each bridge arm submodule is obtained according to a preset time interval. The cumulative number of switching operations for each bridge arm submodule within a preset time period is determined based on the cumulative number of switching operations for each bridge arm submodule, and the switching operation number change curve is generated.

3. A flexible DC transmission converter valve submodule capacitance attenuation monitoring device, characterized in that, include: The change curve determination unit is used to determine the change curve of the number of switching based on the cumulative number of switching of each bridge arm sub-module. The target matrix construction unit is used to construct an attenuation monitoring target matrix based on the change curve of the number of switching operations. A capacitor attenuation determination unit is used to determine the converter valve submodule with capacitor attenuation based on the attenuation monitoring target matrix. The target matrix construction unit includes: The distance determination module is used to determine the Hausdorf distance between the switching frequency variation curves corresponding to each bridge arm submodule; The maximum and minimum value determination module is used to determine the maximum and average values ​​of Hausdorf distances corresponding to each bridge arm sub-module; The target matrix construction module is used to construct the attenuation monitoring target matrix based on the maximum value and the average value. The capacitance attenuation determination unit includes: The extreme value determination module is used to select the sub-module pairs that appear in the attenuation monitoring target matrix and calculate the maximum value of the Hausdorf distance between the switching number curves corresponding to the two sub-modules in the sub-module pair; The capacitor attenuation screening module is used to determine the converter valve sub-module that has capacitor attenuation based on the maximum value of the corresponding sub-module. Specifically, the submodule numbers appearing in the attenuation monitoring target matrix are selected, and the maximum value of the Hausdorff distance between the switching curves of the submodules after screening is calculated. If the maximum value of the Hausdorff distance is less than the average value of the Hausdorff distance, the corresponding two submodules are excluded. The remaining submodule numbers after sequential discrimination are the submodule numbers of capacitor attenuation. If the calculation results all satisfy the condition that the maximum value of the Hausdorff distance is greater than the average value of the Hausdorff distance, then the submodule numbers appearing in the attenuation monitoring target matrix are all submodule numbers of capacitor attenuation.

4. The flexible DC transmission converter valve submodule capacitance attenuation monitoring device according to claim 3, characterized in that, The curve determination unit includes: The switching count acquisition module is used to acquire the cumulative switching count of each bridge arm submodule according to a preset time interval; The change curve generation module is used to determine the cumulative number of times each bridge arm submodule is switched over a preset time based on the cumulative number of switching times of each bridge arm submodule, and generate the change curve of the number of switching times.

5. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the flexible DC transmission converter valve submodule capacitance attenuation monitoring method according to any one of claims 1 to 2.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the method for monitoring capacitance attenuation of a flexible DC transmission converter valve submodule as described in any one of claims 1 to 2.

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