Phase commutation failure detection method and device, equipment and medium

Abstract

The invention discloses a commutation failure detection method and device, equipment and a medium, and the method comprises the steps: carrying out the derivation of the current waveform of each converter valve, and obtaining the curvature of the current waveform of each converter valve; according to the curvature of the current waveform of each converter valve and a preset curvature threshold, determining a corresponding time vector when commutation failure occurs in each commutation condition; combining the corresponding time vectors when all commutation conditions fail, and generating a commutation failure moment matrix; and based on the commutation failure moment matrix, determining the converter valve of the converter with the commutation failure for the first time and the commutation failure moment. According to the method, the converter valve with the first commutation failure of the converter and the commutation failure time are determined through the current curvature of each converter valve, so that the commutation failure position is accurately positioned, subsequent fault processing and maintenance work is facilitated, faults in a larger range caused by the commutation failure are reduced, and the stability of a high-voltage direct-current power transmission system is improved.

Description

Technical Field

[0001] This invention relates to the field of power system technology, and in particular to methods, devices, equipment and media for detecting commutation failure. Background Technology

[0002] In high-voltage direct current (HVDC) transmission systems, converters, as the core equipment for power conversion, are crucial for system stability due to their condition monitoring. The operating states of converters are complex, especially during commutation failures, when the presence of bypass pairs further complicates their operation. There are as many as 45 normal operating modes for converters, and commutation failure is one of the most common faults in HVDC transmission systems. The thyristor, the basic unit of the converter valve and a semi-controlled device, directly reflects the valve's state through its on / off processes affecting the valve current. Therefore, monitoring the valve current is of great significance for clearly and reliably detecting the converter valve's operating status and achieving visualized analysis of the converter.

[0003] However, there is currently no effective method for detecting commutation failure in actual engineering projects, which makes it impossible to locate commutation failure problems in a timely manner, reducing system stability and causing more widespread failures. Summary of the Invention

[0004] Therefore, it is necessary to propose methods, devices, equipment, and media for detecting commutation failures to address the aforementioned issues, so as to achieve timely and accurate location of commutation failures, facilitate subsequent fault handling and maintenance, reduce the wider range of faults caused by commutation failures, and improve the stability of high-voltage direct current transmission systems.

[0005] To achieve the above objectives, the first aspect of this application provides a commutation failure detection method, the method comprising:

[0006] Based on the current signals of each converter valve obtained in the converter, the current waveform of each converter valve is determined.

[0007] Differentiate the current waveform of each of the aforementioned converter valves to obtain the curvature of the current waveform of each of the aforementioned converter valves;

[0008] Based on the curvature of the current waveform of each converter valve and a preset curvature threshold, the time vector corresponding to the commutation failure in each commutation case is determined, wherein the commutation case is a combination of two converter valves that have performed a commutation operation.

[0009] Merge the time vectors corresponding to all commutation failures to generate a commutation failure time matrix;

[0010] Based on the commutation failure time matrix, determine the commutation valve at which the first commutation failure of the converter occurs, and the time of the commutation failure.

[0011] Furthermore, determining the time vector corresponding to commutation failure for each commutation condition based on the curvature of the current waveform of each of the converter valves and a preset curvature threshold specifically includes:

[0012] Based on the curvature of the current waveform of each of the aforementioned converter valves and a preset first curvature threshold, the target commutation condition for the nth commutation operation is determined, where n is a positive integer and n is less than or equal to N, and N is the total number of commutation operations. The target commutation condition is the combination of the first converter valve and the second converter valve that commutate during the nth commutation operation, where the first converter valve is the valve that is about to exit and the second converter valve is the valve that is about to open.

[0013] Based on the comparison of the curvature of the current waveforms of the first converter valve and the second converter valve and a preset second curvature threshold, it is determined whether the target commutation situation has failed during the nth commutation operation, wherein the first curvature threshold is greater than the second curvature threshold;

[0014] If a commutation failure is determined to have occurred, a corresponding time vector is generated based on the moment when the commutation failure occurred under the target commutation condition.

[0015] Furthermore, determining the target commutation condition for the nth commutation operation based on the curvature of the current waveform of each of the converter valves and a preset first curvature threshold specifically includes:

[0016] After the (n-1)th commutation operation is completed, the two commutator valves whose current waveform curvature exceeds the preset first curvature threshold are designated as the first commutator valve and the second commutator valve, and the combination of the first commutator valve and the second commutator valve is designated as the target commutation situation corresponding to the nth commutation operation.

[0017] Furthermore, the step of comparing the curvature of the current waveforms of the first and second commutator valves with a preset second curvature threshold to determine whether the target commutation failure occurs during the nth commutation operation specifically includes:

[0018] After the (n-1)th commutation operation is completed, the moment when the curvature of the current waveform first exceeds the preset first curvature threshold is taken as the commutation start time of the nth commutation operation;

[0019] Starting from the commutation start time, the commutation end time of the nth commutation operation is determined based on the curvature of the current waveforms of the first commutator valve and the second commutator valve.

[0020] The curvature of the current waveforms of the first and second commutator valves at the end of the commutation is compared with a preset second curvature threshold to determine whether the target commutation failure occurs during the nth commutation operation.

[0021] Furthermore, the step of comparing the curvature of the current waveforms of the first and second commutator valves at the commutation end time with a preset second curvature threshold to determine whether the target commutation failure occurred during the nth commutation operation specifically includes:

[0022] When the curvature of the current waveform of the first commutator valve at the end of the commutation is greater than the preset second curvature threshold, and the curvature of the current waveform of the second commutator valve is greater than the second curvature threshold, it is determined that the target commutation situation has not failed during the target commutation operation.

[0023] If the curvature of the current waveform of the first commutator valve at the end of the commutation is not greater than the second curvature threshold, it is determined that the target commutation situation has failed during the target commutation operation.

[0024] If the curvature of the current waveform of the second commutator at the end of the commutation is not greater than the second curvature threshold, it is determined that the target commutation condition has failed during the target commutation operation.

[0025] Furthermore, the step of differentiating the current waveforms of each of the converter valves to obtain the curvature of the current waveforms of each converter valve specifically includes:

[0026] By taking the second derivative of the current waveform of each of the aforementioned converter valves, the first and second derivatives of the current waveform of each of the aforementioned converter valves are obtained.

[0027] The curvature of the current waveform of each of the aforementioned converter valves is calculated based on the first and second derivatives of the current waveform of each converter valve.

[0028] Furthermore, the curvature of the current waveform of the converter valve is calculated using the following formula:

[0029]

[0030] In the formula, K VTM Let i″ be the curvature of the Mth converter valve. VTM Let i′ be the second derivative of the current waveform of the Mth converter valve. VTM Let be the first derivative of the current waveform of the Mth converter valve.

[0031] To achieve the above objectives, a second aspect of this application provides a commutation failure detection device, the device comprising:

[0032] The parameter acquisition module is used to determine the current waveform of each converter valve based on the acquired current signals of each converter valve in the converter.

[0033] Differentiate the current waveform of each of the aforementioned converter valves to obtain the curvature of the current waveform of each of the aforementioned converter valves;

[0034] The commutation detection module is used to determine the time vector corresponding to the commutation failure in each commutation case based on the curvature of the current waveform of each commutator and a preset curvature threshold, wherein the commutation case is a combination of two commutator valves that have performed a commutation operation.

[0035] The commutation failure determination module is used to merge the time vectors corresponding to all commutation failures and generate a commutation failure time matrix.

[0036] Based on the commutation failure time matrix, determine the commutation valve at which the first commutation failure of the converter occurs, and the time of the commutation failure.

[0037] To achieve the above objectives, a third aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, causes the processor to perform the steps of the method described in the first aspect.

[0038] To achieve the above objectives, a fourth aspect of this application provides a computer device including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the steps of the method described in the first aspect.

[0039] The embodiments of the present invention have the following beneficial effects:

[0040] This invention proposes a commutation failure detection method, which includes: determining the current waveform of each converter valve based on the acquired current signals of each converter valve within the converter; differentiating the current waveform of each converter valve to obtain the curvature of the current waveform of each converter valve; determining the time vector corresponding to the occurrence of commutation failure for each commutation condition based on the curvature of the current waveform of each converter valve and a preset curvature threshold, wherein the commutation condition is a combination of two converter valves undergoing commutation operation; merging the time vectors corresponding to the failure of all commutation conditions to generate a commutation failure time matrix; and determining the converter valve in which the converter first experiences a commutation failure and the commutation failure time based on the commutation failure time matrix. This invention calculates the curvature of the current waveform of each converter valve and determines the converter valve in which the converter first experiences a commutation failure and the commutation failure time based on the magnitude of the curvature, thereby accurately locating the commutation failure position, facilitating subsequent fault handling and maintenance, reducing the wider range of faults caused by commutation failure, and improving the stability of the high-voltage direct current transmission system. Attached Figure Description

[0041] 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.

[0042] in:

[0043] Figure 1 This is a flowchart illustrating the commutation failure detection method in an embodiment of the present invention.

[0044] Figure 2 This is a waveform diagram of the valve current during normal commutation in an embodiment of the present invention;

[0045] Figure 3 This is a structural block diagram of the commutation failure detection device in an embodiment of the present invention;

[0046] Figure 4 This is an internal structural diagram of a computer device in an embodiment of the present invention. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] One embodiment of the present invention proposes a commutation failure detection method, which can be referred to in the following text. Figure 1 , Figure 1 This is a flowchart illustrating the commutation failure detection method in an embodiment of the present invention. The method includes:

[0049] Step 100: Determine the current waveform of each converter valve based on the current signals of each converter valve obtained in the converter.

[0050] In this embodiment, the converter is a 12-pulse converter, which is composed of two sets of 6-pulse converters connected in series or parallel. The 6-pulse converter consists of six converter valves, the main component of which is a thyristor. These six valves are arranged in two groups: VT1, VT3, and VT5 form a common-cathode cathode commutation group, and VT2, VT4, and VT6 form a common-anode anode commutation group. By acquiring the current signals of the 12 converter valves in the converter in real time, the current waveform of each converter valve can be determined.

[0051] Step 200: Differentiate the current waveform of each converter valve to obtain the curvature of the current waveform of each converter valve.

[0052] In this embodiment, the valve current function is determined by acquiring the valve current waveform. The valve current function has inflection points at both the start and end of commutation, exhibiting a certain degree of curvature. Therefore, its curvature can be calculated based on the valve current function, and the curvature can be used to represent the degree of curvature of the valve current function to determine whether there is an inflection point in the valve current function and whether the commutation operation is proceeding normally.

[0053] Based on this, after acquiring the current waveforms of each converter valve in real time, the derivative of the current waveforms is calculated to obtain the curvature of the current waveforms of each converter valve, and the success of the commutation operation is determined based on the magnitude of the curvature.

[0054] Step 300: Based on the curvature of the current waveform of each converter valve and the preset curvature threshold, determine the time vector corresponding to the commutation failure in each commutation case, where the commutation case is the combination of two converter valves that have performed the commutation operation.

[0055] During normal operation of a high-voltage direct current transmission system (LCC-HVDC), at any given commutation moment, the commutation process occurs only between a specific pair of converter valves. For example, in a 6-pulse bridge, VT1 commutates to VT3. After this event ends, at a specific moment in the next cycle, it will be VT2's turn to commutate to VT4. Therefore, there is only one commutation situation for each commutation operation.

[0056] In one embodiment, the converter consists of two sets of 6-pulse converters. Each 6-pulse converter consists of 6 converter valves, including VT1, VT3, VT5, VT2, VT4, and VT6. Each 6-pulse converter includes 6 commutation scenarios: VT1→VT3 (meaning valve VT1 commutates to VT3), VT3→VT5, VT5→VT1, VT2→VT4, VT4→VT6, and VT6→VT2. Therefore, the two sets of 6-pulse converters contain a total of 12 commutation scenarios.

[0057] By determining the failure status of each commutation operation, the time of each commutation failure is included in the time vector of the corresponding commutation status, so as to obtain the time vector corresponding to the commutation failure in each commutation status.

[0058] When commutation is running normally, the valve current waveform has a large curvature at the inflection point at the start of commutation. This characteristic can be used as a criterion for the start of commutation of the two valves. At the inflection point at the end of commutation, the derivative of the valve current function crosses zero, and the valve current function has an extreme point. This characteristic can be used as a criterion for the end of commutation of the two valves. When commutation fails, the two converter valves will continue to reverse commutation after the commutation ends, resulting in a longer commutation time for the two converter valves and a smaller curvature of the valve current waveform, which is much smaller than the curvature near the extreme point of the valve current at the end of normal commutation.

[0059] For reference Figure 2 , Figure 2 This is a waveform diagram of the valve current during normal commutation in an embodiment of the present invention. Figure 2 The diagram shows the waveform changes of the valve current, its differential, and curvature under normal commutation conditions from VT3 to VT5. It can be seen that when VT3 begins commutation to VT5 (t = α / ω), the valve current i... VT3 and i VT5 The curvatures are 0.118937 and 0.136073, respectively; when i VT3 and i VT5 When commutation ends (t=(α+μ) / ω), the curvatures of valve currents iVT3 and iVT5 are 0.0320644 and 0.028814, respectively. The curvatures of the valve currents at these two special moments are much higher than the curvatures at other moments in the entire commutation process.

[0060] Based on this, embodiments of the present invention determine whether the system has experienced commutation failure by determining the curvature near the extreme point of the valve current function.

[0061] In this embodiment, a preset curvature threshold is used to determine whether the curvature of the current waveform of the converter valve meets the standard for normal commutation operation. The normality of commutation operation is determined by comparing the curvature of the current waveform of each converter valve with the preset curvature threshold.

[0062] Step 400: Merge the time vectors corresponding to all commutation failures to generate a commutation failure time matrix.

[0063] In this embodiment, the time vectors corresponding to each commutation condition are combined according to a preset commutation sequence to obtain a commutation failure time matrix. This commutation failure time matrix is ​​a 12-row matrix, which can be understood as each time vector being a row of the matrix. Through ordered merging, the commutation failure time matrix forms a complete, system-wide fault time record table. In this "table," each row uniquely corresponds to a specific commutation combination. Each column can be viewed as a fault event index on a time series.

[0064] Step 500: Determine the converter valve at which the first commutation failure occurs and the commutation failure time based on the commutation failure time matrix.

[0065] In this embodiment, the first non-zero column is searched in the commutation failure time matrix. This first non-zero column represents the time when the first commutation failure of the entire system was recorded. In other words, the time corresponding to the first non-zero column is the time of the first commutation failure. The commutation situation corresponding to the smallest element in the first non-zero column is the converter valve that first experienced a commutation failure. Since multiple valves may fail within a very short time (theoretically within the same calculation cycle), searching for the smallest element in the first non-zero column is to find the earliest commutation failure among all recorded failure times in that column. The time point of this commutation failure is the commutation failure time of the first valve in the entire converter to experience a commutation failure.

[0066] This invention searches for the moment of the first commutation failure of the converter by acquiring the current waveform of the converter valve, so as to detect the commutation failure fault in a timely manner; based on the current waveform characteristics at the time of commutation failure, the current waveform of each converter valve is judged to determine the converter valve that failed commutation and the time of commutation failure, so as to accurately locate the location of commutation failure, facilitate subsequent fault handling and maintenance work, thereby reducing the wider range of faults caused by commutation failure and improving the stability of the high voltage direct current transmission system.

[0067] In one embodiment of the present invention, the commutation operation of the converter is detected based on a commutation failure detection system. The commutation failure detection system includes an input module, a commutation failure detection module, and a module for determining the first valve commutation failure time.

[0068] The input module differentiates the current waveforms of the 12 converter valves to obtain the curvature of the current waveform of each converter valve, and inputs them together as a dataset into the commutation failure detection module.

[0069] There are 12 commutation scenarios between the valves in the 12-pulse converter. According to the commutation scenario, the commutation failure detection module includes 12 commutation failure detection units. Each unit number corresponds to a commutation scenario. For example, the commutation failure detection unit numbered 2141 is used to detect whether a commutation failure occurs during the commutation process of the converter valves VT21 and VT41. If a commutation failure occurs, the commutation failure time is recorded in the vector t_cf2141. After all 12 commutation failure detection units have completed their detection, the commutation failure time vector is used as the result input to determine the first valve commutation failure time module.

[0070] To determine the first valve commutation failure time module, the 12 independent commutation failure time vectors are first combined into a 12-row matrix according to a pre-defined order. This can be understood as treating each vector as a row of the matrix. For example, the vector t_cf2141 from commutation failure detection unit number 2141 becomes the first row of the t_cf matrix. t_cf3151 from commutation failure detection unit number 3151 becomes the second row, and so on, until the vector from the 12th detection unit becomes the 12th row. Through this ordered merging, the commutation failure time matrix t_cf forms a fault time record table.

[0071] In one embodiment of the present invention, step 200, differentiating the current waveforms of each converter valve to obtain the curvature of the current waveforms of each converter valve, specifically includes:

[0072] Step 210: Perform a second derivative on the current waveform of each converter valve to obtain the first and second derivatives of the current waveform of each converter valve.

[0073] In one embodiment, taking the commutation process from VT3 to VT5 as an example, the valve current flowing through the two valves is as follows:

[0074]

[0075] In the formula, i VT3 and i VT5 Let ω be the instantaneous current flowing through converter valves VT3 and VT5, respectively, ω be the angular frequency of the AC power grid, α be the firing angle of converter valve VT5, and E be the instantaneous current flowing through converter valves VT3 and VT5, respectively. m This represents the peak value of the AC phase current, which is 2πf, where f is the frequency of the power grid (typically 50Hz). r For commutation inductance, I d denoted as ν, where μ is the steady-state DC current transmitted on the DC line, t is the commutation angle, and t represents time.

[0076] From the above equation, it can be seen that during the commutation process, the valve currents flowing through the two commutation valves are piecewise functions. ωt=α and ωt=α+μ are the starting and ending points of the commutation process, respectively, and ωt=α and ωt=α+μ are two inflection points. The part of the function between them, i.e., the interval α≤ωt≤α+μ, is the mathematical representation of the dynamic changes in the currents of the two commutation valves during the commutation period. Differentiating the two valve current functions between the two inflection points:

[0077] For the converter valve VT5, its current function is:

[0078] Find the first derivative:

[0079] During the inverse transform phase, α ≤ ωt ≤ α + μ, and α > 90°, the value of sin(ωt) is positive. Therefore, i′ VT5 >0.

[0080] Find the second derivative:

[0081] During the inverse transform phase, cos(ωt) is negative. Therefore, i” VT5 <0.

[0082] For the converter valve VT3, its current function is i VT3 =I d -i VT5 :

[0083] Find the first derivative: Therefore i′ VT5 It is positive, so i′ VT3 <0.

[0084] Find the second derivative: Because i” VT5 <0, so i” VT3 >0.

[0085] Step 220: Calculate the curvature of the current waveform of each converter valve based on the first and second derivatives of the current waveform of each converter valve.

[0086] In this embodiment, the 12-pulse converter is composed of two 6-pulse converter bridges connected in series or in parallel. Here, a 6-pulse bridge (containing 6 valves, numbered 1 to 6) is used to introduce the curvature calculation method, which is applicable to all 12 valves in the 12-pulse converter.

[0087] To quantify the curvature of the valve current waveform, this embodiment uses curvature to describe the degree of waveform curvature. The formula for calculating curvature is as follows:

[0088]

[0089] In the formula, K VTM Let i″ be the curvature of the Mth converter valve. VTM Let i′ be the second derivative of the current waveform of the Mth converter valve. VTM Let be the first derivative of the current waveform of the Mth converter valve.

[0090] Taking the commutation from valve VT3 to valve VT5 as an example, the curvature of both VT3 and VT5 needs to be calculated separately. When determining the curvature of the current waveform of VT3, M = 3, and the curvature is:

[0091]

[0092] When determining the curvature of the current waveform of the converter valve VT5, M = 5, and the curvature is:

[0093]

[0094] In one embodiment of the present invention, step 300, determining the time vector corresponding to commutation failure for each commutation condition based on the curvature of the current waveform of each converter valve and a preset curvature threshold, specifically includes:

[0095] Step 310: Based on the curvature of the current waveform of each converter valve and the preset first curvature threshold, determine the target commutation situation for the nth commutation operation, where n is a positive integer and n is less than or equal to N, N is the total number of commutation operations, and the target commutation situation is the combination of the first and second converter valves that will commutate during the nth commutation operation, where the first converter valve is the valve that is about to exit and the second converter valve is the valve that is about to turn on.

[0096] Since the system operates continuously, multiple commutation operations may be detected at different times for each commutation condition. Whether a commutator valve has entered a commutation operation can be determined based on the curvature of each commutator valve.

[0097] In one embodiment, Step 310, based on the curvature of the current waveform of each converter valve and a preset first curvature threshold, determines the target commutation situation for the nth commutation operation. Specifically, after the (n-1)th commutation operation, the two converter valves whose current waveform curvature exceeds the preset first curvature threshold are designated as the first converter valve and the second converter valve, and the combination of the first converter valve and the second converter valve is designated as the target commutation situation corresponding to the nth commutation operation.

[0098] Specifically, after the previous commutation operation is detected, the curvature of all converter valves is calculated and detected. When a converter valve whose current curvature exceeds the first curvature threshold for the first time is detected, that valve is identified as the converter valve currently performing a commutation operation. It can be understood that only two converter valves operate during each commutation operation. That is, if the current curvature of two converter valves simultaneously exceeds the first curvature threshold, then those two valves are the ones performing the current commutation operation.

[0099] Step 320: Based on the curvature of the current waveforms of the first and second converter valves and the preset second curvature threshold, determine whether the target commutation failure occurs during the nth commutation operation, wherein the first curvature threshold is greater than the second curvature threshold.

[0100] After determining the first and second commutator valves at the nth commutation operation, the curvature of the current waveforms of the first and second commutator valves can be detected. The commutation failure can be determined based on the curvature magnitude at the end of the commutation and the second curvature threshold.

[0101] In one embodiment, Step 320, by comparing the curvature of the current waveforms of the first and second converter valves with a preset second curvature threshold, determines whether the target commutation failure occurs during the nth commutation operation, specifically including:

[0102] Step 321: After the (n-1)th commutation operation, the moment when the curvature of the current waveform first exceeds the preset first curvature threshold is taken as the commutation start time of the nth commutation operation; from the commutation start time, the commutation end time of the nth commutation operation is determined based on the curvature of the current waveforms of the first converter valve and the second converter valve.

[0103] Specifically, after the previous commutation operation is completed, the start time of the current commutation operation is determined by comparing the first curvature threshold with the curvature of all commutation valves. From the start time, the current of the first and second commutation valves that are currently undergoing commutation operation is monitored to determine the end time of the current commutation operation.

[0104] Step 322: Compare the curvature of the current waveforms of the first and second commutator valves at the end of the commutation with the preset second curvature threshold to determine whether the target commutation failure occurs during the nth commutation operation.

[0105] In one embodiment of the present invention, when the curvature of the current waveform of the first commutator valve at the end of commutation is greater than a preset second curvature threshold, and the curvature of the current waveform of the second commutator valve is greater than the second curvature threshold, it is determined that the target commutation situation has not failed during the target commutation operation.

[0106] If the curvature of the current waveform of the first commutator valve at the end of the commutation is not greater than the second curvature threshold, it is determined that the target commutation situation has failed during the target commutation operation.

[0107] If the curvature of the current waveform of the second commutator valve at the end of the commutation is not greater than the second curvature threshold, it is determined that the target commutation failure occurred during the target commutation operation.

[0108] Specifically:

[0109]

[0110] In the formula, K d K is the first current valve. u For the second current valve, K VTset2 This is the second curvature threshold.

[0111] Step 330: If a commutation failure is determined to have occurred, a corresponding time vector is generated based on the moment when the commutation failure occurred in the target commutation situation.

[0112] Specifically, when a commutation failure is detected during the nth commutation operation, the moment of the failure is included in the time vector of the corresponding target commutation situation. For example, if the commutator valve VT3 commutates to VT5 during the nth commutation operation, the moment of the commutation failure during the nth commutation operation is included in the time vector corresponding to the commutation from VT3 to VT5. In this embodiment, the moment of commutation failure can be the moment commutation occurs, the moment commutation ends, or any moment during the commutation process; no limitation is imposed here.

[0113] This invention enables the detection of commutation failures by real-time monitoring of the curvature of the converter valve. Furthermore, based on the current waveform characteristics at the time of commutation failure, the current waveform of the converter valve is used to determine the commutation failure, thereby identifying the converter valve and the time of commutation failure. This allows for precise location of the commutation failure, facilitating subsequent fault handling and maintenance, reducing the risk of larger-scale faults caused by commutation failures, and improving the stability of the high-voltage direct current transmission system.

[0114] One embodiment of the present invention provides a commutation failure detection device; please refer to [link to relevant documentation]. Figure 3 , Figure 3 This is a structural block diagram of the commutation failure detection device according to an embodiment of the present invention. The device includes:

[0115] The parameter acquisition module 301 is used to determine the current waveform of each converter valve based on the acquired current signals of each converter valve in the converter.

[0116] Differentiate the current waveform of each converter valve to obtain the curvature of the current waveform of each converter valve.

[0117] The commutation detection module 302 is used to determine the time vector corresponding to the commutation failure in each commutation situation based on the curvature of the current waveform of each converter valve and the preset curvature threshold. The commutation situation is the combination of two converter valves that have performed commutation operation.

[0118] The commutation failure determination module 303 is used to merge the time vectors corresponding to all commutation failures to generate a commutation failure time matrix; and to determine the converter valve where the first commutation failure of the converter occurs, as well as the commutation failure time, based on the commutation failure time matrix.

[0119] The commutation failure detection device proposed in this invention searches for the moment of the first commutation failure of the converter by acquiring the current waveform of the converter valve, so as to detect the commutation failure fault in a timely manner; based on the current waveform characteristics at the time of commutation failure, the device judges the commutation failure of each converter valve to determine the converter valve that failed the commutation and the time of commutation failure, so as to accurately locate the commutation failure position, facilitate subsequent fault handling and maintenance work, thereby reducing the wider range of faults caused by commutation failure and improving the stability of the high voltage direct current transmission system.

[0120] Figure 4 An internal structural diagram of a computer device according to one embodiment of the present invention is shown. This computer device can specifically be a terminal or a system. Figure 4 As shown, the computer device includes a processor, memory, and network interface connected via a system bus. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system and may also store a computer program. When executed by the processor, this computer program causes the processor to perform the steps in the above-described method embodiments. The internal memory may also store a computer program, which, when executed by the processor, causes the processor to perform the steps in the above-described method embodiments. Those skilled in the art will understand that... Figure 4 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0121] In one embodiment, a computer device is provided, including a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform the steps in the above method embodiments.

[0122] In one embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, causes the processor to perform the steps in the above method embodiments.

[0123] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments described above. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0124] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0125] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for detecting commutation failure, characterized in that, The method includes: Based on the current signals of each converter valve obtained in the converter, the current waveform of each converter valve is determined. Differentiate the current waveform of each of the aforementioned converter valves to obtain the curvature of the current waveform of each of the aforementioned converter valves; Based on the curvature of the current waveform of each converter valve and a preset curvature threshold, the time vector corresponding to the commutation failure in each commutation case is determined, wherein the commutation case is a combination of two converter valves that have performed a commutation operation. Merge the time vectors corresponding to all commutation failures to generate a commutation failure time matrix; Based on the commutation failure time matrix, determine the commutation valve at which the first commutation failure of the converter occurs, and the time of the commutation failure.

2. The method as described in claim 1, characterized in that, The step of determining the time vector corresponding to commutation failure for each commutation condition based on the curvature of the current waveform of each of the converter valves and a preset curvature threshold specifically includes: Based on the curvature of the current waveform of each of the converter valves and a preset first curvature threshold, the target commutation condition for the nth commutation operation is determined, where n is a positive integer and n is less than or equal to N, and N is the total number of commutation operations. The target commutation condition is the combination of the first converter valve and the second converter valve that commutate during the nth commutation operation, where the first converter valve is the valve that is about to exit and the second converter valve is the valve that is about to open. Based on the comparison of the curvature of the current waveforms of the first converter valve and the second converter valve and a preset second curvature threshold, it is determined whether the target commutation situation has failed during the nth commutation operation, wherein the first curvature threshold is greater than the second curvature threshold; If a commutation failure is determined to have occurred, a corresponding time vector is generated based on the moment when the commutation failure occurred under the target commutation condition.

3. The method as described in claim 2, characterized in that, The step of determining the target commutation condition for the nth commutation operation based on the curvature of the current waveform of each of the converter valves and a preset first curvature threshold specifically includes: After the (n-1)th commutation operation is completed, the two commutation valves whose current waveform curvature exceeds the preset first curvature threshold are designated as the first commutation valve and the second commutation valve, and the combination of the first commutation valve and the second commutation valve is designated as the target commutation situation corresponding to the nth commutation operation.

4. The method as described in claim 3, characterized in that, The step of comparing the curvature of the current waveforms of the first and second commutator valves with a preset second curvature threshold to determine whether the target commutation failure occurs during the nth commutation operation specifically includes: After the (n-1)th commutation operation is completed, the moment when the curvature of the current waveform first exceeds the preset first curvature threshold is taken as the commutation start time of the nth commutation operation; Starting from the commutation start time, the commutation end time of the nth commutation operation is determined based on the curvature of the current waveforms of the first commutator valve and the second commutator valve. The curvature of the current waveforms of the first and second commutator valves at the end of the commutation is compared with a preset second curvature threshold to determine whether the target commutation failure occurs during the nth commutation operation.

5. The method as described in claim 4, characterized in that, The step of comparing the curvature of the current waveforms of the first and second commutator valves at the commutation end time with a preset second curvature threshold to determine whether the target commutation failure occurs during the nth commutation operation specifically includes: When the curvature of the current waveform of the first commutator valve at the end of the commutation is greater than the preset second curvature threshold, and the curvature of the current waveform of the second commutator valve is greater than the second curvature threshold, it is determined that the target commutation situation has not failed during the target commutation operation. If the curvature of the current waveform of the first commutator valve at the end of the commutation is not greater than the second curvature threshold, it is determined that the target commutation situation has failed during the target commutation operation. If the curvature of the current waveform of the second commutator at the end of the commutation is not greater than the second curvature threshold, it is determined that the target commutation condition has failed during the target commutation operation.

6. The method as described in claim 1, characterized in that, The step of differentiating the current waveforms of each of the converter valves to obtain the curvature of the current waveforms of each converter valve specifically includes: By taking the second derivative of the current waveform of each of the aforementioned converter valves, the first and second derivatives of the current waveform of each of the aforementioned converter valves are obtained. The curvature of the current waveform of each of the aforementioned converter valves is calculated based on the first and second derivatives of the current waveform of each converter valve.

7. The method as described in claim 1, characterized in that, The curvature of the current waveform of the converter valve is calculated using the following formula: In the formula, K VTM Let i″ be the curvature of the Mth converter valve. VTM Let i′ be the second derivative of the current waveform of the Mth converter valve. VTM Let be the first derivative of the current waveform of the Mth converter valve.

8. A commutation failure detection device, characterized in that, The device includes: The parameter acquisition module is used to determine the current waveform of each converter valve based on the acquired current signals of each converter valve in the converter. Differentiate the current waveform of each of the aforementioned converter valves to obtain the curvature of the current waveform of each of the aforementioned converter valves; The commutation detection module is used to determine the time vector corresponding to the commutation failure in each commutation case based on the curvature of the current waveform of each commutator and a preset curvature threshold, wherein the commutation case is a combination of two commutator valves that have performed a commutation operation. The commutation failure determination module is used to merge the time vectors corresponding to all commutation failures and generate a commutation failure time matrix. Based on the commutation failure time matrix, determine the commutation valve at which the first commutation failure of the converter occurs, and the time of the commutation failure.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it causes the processor to perform the steps of the method as described in any one of claims 1 to 7.

10. A computer device, comprising a memory and a processor, characterized in that, The memory stores a computer program that, when executed by the processor, causes the processor to perform the steps of the method as described in any one of claims 1 to 7.

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