High-voltage direct current commutation failure detection method and system adaptive to multiple types

Abstract

The invention relates to the technical field of electric power, and discloses a high-voltage direct current commutation failure detection method and system adaptive to multiple types, and the method comprises the steps: firstly analyzing a valve side current waveform of a target system through a primary commutation failure criterion obtained through pre-analysis, and accurately obtaining a primary commutation result; the method comprises the following steps: firstly, determining a primary commutation failure time, then determining a two-time commutation failure interval according to the commutation failure time of the primary commutation failure, and finally obtaining two-time commutation results in combination with two-time commutation failure criteria obtained through pre-analysis, can accurately identify different types of commutation results in the high-voltage direct-current power transmission system, accurately judges whether different commutation failure conditions occur or not, and improves the detection accuracy of the high-voltage direct-current power transmission system. And the operation stability of the high-voltage direct-current power transmission system is improved.

Description

Technical Field

[0001] The present invention relates to the field of electric power technology, and in particular to a method and system for detecting high-voltage direct current commutation failures that are adaptable to multiple types. Background Art

[0002] The inverter is prone to commutation failure, which is one of the main defects of high-voltage direct current transmission projects using grid-commutated converters. In one power frequency cycle, a 6-pulse converter will have at most two commutation failures, and there are only three types of commutation failures: one commutation failure, two consecutive commutation failures, and two discontinuous commutation failures. At present, the differential current criterion composed of valve-side AC and DC currents is used in actual projects to detect commutation failures. The differential current criterion represents the abnormal valve state after the converter is bypassed, and has no perception ability for commutation failures before bypassing, resulting in the differential current moment of the valve area protection criterion not corresponding to the moment of the abnormal valve state. In addition, affected by multiple factors such as fault type, system strength, fault strength, DC operating conditions, fault closing angle, control adjustment, etc., the differential current criterion has the risk of insufficient sensitivity.

[0003] Therefore, in the HVDC transmission system, accurate detection of commutation failure is crucial for the stable operation of the system. At present, the existing technology uses two typical dynamic characteristics to identify a commutation failure in the detection of commutation failure. However, in the actual operation scenario, the operation state of the power system is complex and changeable, and the fault types and working conditions are diverse. Relying solely on two typical dynamic characteristics cannot fully cover all possible situations. This leads to the inability to accurately identify commutation failures when facing some special operating conditions or complex fault combinations, thus affecting the reliability and stability of the entire HVDC transmission system. Summary of the invention

[0004] The present invention provides a method and system for detecting high-voltage direct current commutation failures that are adaptable to multiple types, and solves the technical problem of how to improve the operational stability of a high-voltage direct current power transmission system.

[0005] A first aspect of the present invention provides a method for detecting high voltage direct current commutation failures that is adaptable to multiple types, comprising:

[0006] In response to a commutation detection request for a target system, a valve-side current waveform and commutation characteristic data of the target system are acquired;

[0007] Determining a primary commutation result based on the valve-side current waveform and a preset primary commutation failure criterion;

[0008] When the commutation result is a commutation failure, two commutation failure intervals are determined based on the commutation failure moment of the commutation failure and the commutation characteristic data;

[0009] Based on the two commutation failure intervals, the valve-side current waveform and the preset two commutation failure criteria, two commutation results are determined.

[0010] Optionally, the preset primary commutation failure criterion includes an atypical commutation failure criterion and a typical commutation failure criterion, and determining a primary commutation result based on the valve-side current waveform and the preset primary commutation failure criterion includes:

[0011] When the valve-side current waveform satisfies the atypical commutation failure criterion, it is determined that an atypical commutation failure occurs in the target system;

[0012] When the valve-side current waveform meets the typical commutation failure criterion, it is determined that a typical commutation failure occurs in the target system;

[0013] When the atypical commutation failure or the typical commutation failure does not exist, determining a commutation result as no commutation failure occurs;

[0014] When the atypical commutation failure or the typical commutation failure occurs, a commutation result is determined to be a commutation failure.

[0015] Optionally, when the valve-side current waveform satisfies the atypical commutation failure criterion, determining that an atypical commutation failure occurs in the target system includes:

[0016] Acquire a first-phase valve-side current waveform and a second-phase valve-side current waveform when the valve-side current is a negative value in the valve-side current waveform;

[0017] Determining whether the first-phase valve-side current waveform has an increasing trend;

[0018] When the first-phase valve-side current waveform has an increasing trend, determining whether the increasing trend is greater than a preset first current threshold;

[0019] When the increasing trend is greater than the preset first current threshold, it is determined that a first commutation failure feature exists;

[0020] determining whether the second-phase valve-side current waveform has a minimum value;

[0021] When the second phase valve side current waveform has a minimum value, it is determined that the second commutation failure feature exists;

[0022] determining whether, after the second-phase valve-side current waveform reaches the minimum value, the increasing trend of the second-phase valve-side current waveform is greater than a preset second current threshold;

[0023] When the increasing trend of the second-phase valve-side current waveform is greater than a preset second current threshold, it is determined that a third commutation failure feature exists;

[0024] When the valve-side current waveform simultaneously has the first commutation failure feature, the second commutation failure feature, and the third commutation failure feature, it is determined that an atypical commutation failure occurs in the target system.

[0025] Optionally, the commutation characteristic data includes a steady-state commutation angle, a steady-state triggering angle, a steady-state triggering phase interval, a first commutation valve pre-touch angle, and a second commutation valve pre-touch angle, the two commutation failure intervals include two continuous commutation failure intervals and two discontinuous commutation failure intervals, and the determining of the two commutation failure intervals based on the commutation failure moment of a commutation failure and the commutation characteristic data includes:

[0026] Determine the lower limit of the interval of the two consecutive commutation failure intervals by using the commutation failure moment and the steady-state commutation angle;

[0027] Determine the upper limit value of the interval of the two consecutive commutation failure intervals by using the commutation failure moment and the steady-state trigger angle;

[0028] Determine the lower limit value of the interval of the two discontinuous commutation failure intervals by using the commutation failure moment, the steady-state trigger angle and the first converter valve pre-touch angle;

[0029] The upper limit value of the interval of the two discontinuous commutation failure intervals is determined by using the commutation failure moment, the steady-state trigger phase interval, the steady-state trigger angle and the second converter valve pre-touch angle.

[0030] Optionally, the preset two commutation failure criteria include two continuous commutation failure criteria and two discontinuous commutation failure criteria, and determining two commutation results based on the two commutation failure intervals, the valve-side current waveform and the preset two commutation failure criteria includes:

[0031] Determining two consecutive commutation results based on the two consecutive commutation failure intervals, the valve-side current waveform and the two consecutive commutation failure criteria;

[0032] Based on the two continuous commutation failure intervals, the two discontinuous commutation failure intervals, the valve-side current waveform and the two discontinuous commutation failure criteria, two discontinuous commutation results are determined.

[0033] Optionally, determining two consecutive commutation results based on the two consecutive commutation failure intervals, the valve-side current waveform and the two consecutive commutation failure criteria includes:

[0034] When the one commutation failure is detected, determining whether the operation time of the target system is within the interval of the two consecutive commutation failures;

[0035] When the operation time of the target system is within the interval of two consecutive commutation failures, it is determined that a fourth commutation failure feature exists;

[0036] Determining whether the first-phase valve-side current waveform has an increasing trend;

[0037] When the first-phase valve-side current waveform has an increasing trend, determining whether the first-phase valve-side current waveform has a maximum value;

[0038] When the first-phase valve-side current waveform has a maximum value, determining whether the first-phase valve-side current waveform has a decay trend after the increasing trend reaches the maximum value;

[0039] When the increasing trend of the first phase valve side current waveform reaches a maximum value and then has a decaying trend, it is determined that there is a fifth commutation failure feature;

[0040] Determining whether the attenuation trend is greater than a preset third current threshold;

[0041] When the attenuation trend is greater than the preset third current threshold, it is determined that the sixth commutation failure feature exists;

[0042] Acquire a first-phase valve-side current of the first-phase valve-side current waveform in which the first-phase valve-side current is in a first-transformed phase valve-side current under a transformed coordinate;

[0043] Performing a sum operation on the first phase valve-side current and the first conversion phase valve-side current to generate a first sum value;

[0044] Determine whether the first sum value is less than a preset first sum value threshold;

[0045] When the first sum value is less than the preset first sum value threshold, it is determined that the seventh commutation failure feature exists;

[0046] When the valve-side current waveform does not simultaneously have the fourth commutation failure feature, the fifth commutation failure feature, the sixth commutation failure feature, and the seventh commutation failure feature, it is determined that the target system does not have two consecutive commutation failures, and it is determined that the eighth commutation failure feature exists;

[0047] When the valve-side current waveform simultaneously has the fourth commutation failure feature, the fifth commutation failure feature, the sixth commutation failure feature, and the seventh commutation failure feature, it is determined that two consecutive commutation failures occur in the target system.

[0048] Optionally, determining two discontinuous commutation results based on the two continuous commutation failure intervals, the two discontinuous commutation failure intervals, the valve-side current waveform and the two discontinuous commutation failure criteria includes:

[0049] When the one commutation failure is detected, determining whether the operation time of the target system is within the interval of the two discontinuous commutation failures;

[0050] When the operation time of the target system is within the interval of the two discontinuous commutation failures, it is determined that the ninth commutation failure feature exists;

[0051] Determining whether the first-phase valve-side current waveform has a decay trend;

[0052] When the first-phase valve-side current waveform has a decaying trend, determining whether there is an increasing trend after the decaying trend of the first-phase valve-side current waveform reaches a minimum value;

[0053] When the attenuation trend of the first phase valve side current waveform reaches a minimum value and then has an increasing trend, it is determined that there is a tenth commutation failure feature;

[0054] Determining whether the increasing trend is greater than a preset fourth current threshold;

[0055] When the increasing trend is greater than the preset fourth current threshold, it is determined that the eleventh commutation failure feature exists;

[0056] Performing a sum operation on a first-phase valve-side current of the first-phase valve-side current waveform and a second-phase valve-side current of the second-phase valve-side current waveform to generate a second sum;

[0057] Determine whether the second sum is less than a preset second sum threshold;

[0058] When the second sum value is less than the preset second sum value threshold, it is determined that a twelfth commutation failure feature exists;

[0059] When the valve-side current waveform does not simultaneously have the ninth commutation failure feature, the tenth commutation failure feature, the eleventh commutation failure feature and the twelfth commutation failure feature, or has the eighth commutation failure feature, it is determined that the target system does not have two discontinuous commutation failures;

[0060] When the valve-side current waveform simultaneously has the ninth commutation failure feature, the tenth commutation failure feature, the eleventh commutation failure feature and the twelfth commutation failure feature, and does not have the eighth commutation failure feature, it is determined that the target system has two discontinuous commutation failures.

[0061] A second aspect of the present invention provides a high-voltage direct current commutation failure detection system adapted to multiple types, comprising:

[0062] A response module, used to respond to a commutation detection request for a target system, and obtain a valve-side current waveform and commutation characteristic data of the target system;

[0063] A primary commutation determination module, used to determine a primary commutation result based on the valve-side current waveform and a preset primary commutation failure criterion;

[0064] An interval determination module, for determining two commutation failure intervals based on the commutation failure moment of the one commutation failure and the commutation characteristic data when the one commutation result is a commutation failure;

[0065] The two-phase commutation determination module is used to determine the two-phase commutation results based on the two-phase commutation failure intervals, the valve-side current waveform and the preset two-phase commutation failure criteria.

[0066] A third aspect of the present invention provides an electronic device, comprising a memory and a processor, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the processor executes the steps of the method for detecting high-voltage direct current commutation failures adapted to multiple types as described in any one of the above items.

[0067] A fourth aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed, the method for detecting high-voltage direct current commutation failures adapted to multiple types as described in any one of the above items is implemented.

[0068] It can be seen from the above technical solutions that the present invention has the following advantages:

[0069] In the present invention, in response to a commutation detection request for a target system, a valve-side current waveform and commutation characteristic data of the target system are obtained; a commutation result is determined based on the valve-side current waveform and a preset commutation failure criterion; when a commutation result is a commutation failure, a two-commutation failure interval is determined based on the commutation failure moment of the one-commutation failure and the commutation characteristic data; two-commutation results are determined based on the two-commutation failure interval, the valve-side current waveform and the preset two-commutation failure criterion; the present invention first analyzes the valve-side current waveform of the target system through a one-commutation failure criterion obtained by pre-analysis to accurately obtain a commutation result, and then determines the two-commutation failure interval according to the commutation failure moment of the one-commutation failure, and finally obtains the two-commutation results in combination with the two-commutation failure criterion obtained by pre-analysis. The present invention can accurately identify the results of different types of commutation in a high-voltage direct current transmission system, accurately determine whether different commutation failure situations occur, and improve the operating stability of the high-voltage direct current transmission system. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0071] Figure 1 A flowchart of a method for detecting high voltage direct current commutation failures applicable to multiple types of applications provided in the first embodiment of the present invention;

[0072] Figure 2 A flowchart of a method for detecting high voltage direct current commutation failures applicable to multiple types of applications provided in the second embodiment of the present invention;

[0073] Figure 3 A schematic diagram of the valve-side current waveform showing the first typical characteristic of a commutation failure;

[0074] Figure 4 A schematic diagram of the valve-side current waveform showing the second typical characteristic of a commutation failure;

[0075] Figure 5 A schematic diagram of the valve-side current waveform with atypical characteristics of a commutation failure;

[0076] Figure 6 It is a schematic diagram of the valve side current waveform of two consecutive commutation failures;

[0077] Figure 7 It is a schematic diagram of the valve side current waveform of two discontinuous commutation failures;

[0078] Figure 8 The valve side current i is the first phase valve side current waveform x Schematic diagram of the judgment logic;

[0079] Fig. 9 The valve side current i is the second phase valve side current waveform y Schematic diagram of the judgment logic;

[0080] Fig.10 A schematic diagram of obtaining the action level of two commutation failures in different time intervals;

[0081] Fig.11 The valve side current i is the first phase valve side current waveform x Schematic diagram of attenuation criterion;

[0082] Fig.12 It is a schematic diagram of obtaining detection signals of two consecutive commutation failures;

[0083] Fig.13It is a schematic diagram of obtaining two discontinuous commutation failure detection signals;

[0084] Fig.14 It is a schematic diagram of the response of the phase-change failure detection link when a three-phase fault occurs in the DC engineering model 1;

[0085] Fig.15 It is a schematic diagram of the response of the phase-commutation failure detection link when the A phase of the DC engineering model 1 fails;

[0086] Fig.16 It is a schematic diagram of the response of the commutation failure detection link when the C phase fails in the DC engineering model 2;

[0087] Fig.17 It is a schematic diagram of the response of the phase-change failure detection link when there is a three-phase fault in the DC engineering model 2;

[0088] Fig.18 It is a schematic diagram of the response of the phase-commutation failure detection link when the A phase fails in the DC engineering model 2;

[0089] Fig.19 A structural block diagram of a high-voltage direct current commutation failure detection system adapted to multiple types provided in Embodiment 3 of the present invention;

[0090] Fig. 20 This is a structural block diagram of a computer device provided in Embodiment 4 of the present invention. DETAILED DESCRIPTION

[0091] The embodiment of the present invention provides a method and system for detecting high-voltage direct current (HVDC) commutation failures that are adaptable to multiple types, and is used to solve the technical problem of how to improve the operational stability of a high-voltage direct current (HVDC) power transmission system.

[0092] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0093] The prior art discloses a detection method for predicting commutation failure by calculating the turn-off angle using the node impedance matrix and the node voltage interaction factor, and comparing the turn-off angle with the minimum turn-off angle, but it has certain effectiveness; the prior art also discloses a detection method for detecting commutation failure using the dynamic characteristics of valve current and valve voltage respectively. However, in fact, most high-voltage DC projects cannot obtain valve current and valve voltage information; the prior art also discloses using two typical dynamic characteristics of the valve side current of the converter transformer under AC fault to judge the primary commutation failure, which improves the reliability and speed of the primary commutation failure detection compared with the actual engineering scheme. However, for a primary commutation failure with atypical characteristics, this method has the situation of non-action or malfunction; the prior art also discloses introducing a waveform similarity coefficient in the commutation failure prediction link to predict the commutation failure, but the starting threshold of the commutation failure prediction link lacks a theoretical basis; the prior art also discloses using the valve side current polarity characteristics to calculate the valve current, and judging the commutation failure according to the conduction and shutdown criteria of the converter valve, but the engineering implementation of this scheme is difficult.

[0094] Therefore, the above technologies all provide references for the detection of the inverter operation status, but there are still problems such as poor timeliness, low reliability and lack of identification of commutation failure types. The actual engineering solutions and existing technologies still have a lot of room for improvement in detection reliability, sensitivity or engineering implementation, and they are all unable to identify the type of commutation failure.

[0095] In high-voltage direct current (HVDC) transmission systems, accurate detection of commutation failures is crucial to the stable operation of the system. However, existing technologies have many defects in commutation failure detection, resulting in insufficient detection accuracy. For example, some existing technologies use the typical dynamic characteristics of the valve-side current of the converter transformer under AC faults to identify a commutation failure. Although this improves the reliability and speed of primary commutation failure detection to a certain extent, the existing detection methods often fail to operate or malfunction for non-typical characteristics of the valve-side current. This results in the actual operation of the HVDC system, which may threaten the stability of the system due to the inability to accurately detect commutation failures in such special circumstances.

[0096] In addition, when it comes to multiple commutation failures, the prior art lacks in-depth research on two consecutive and two discontinuous commutation failures. Specifically, there is no clear method to determine the time interval range of two consecutive and two discontinuous commutation failures, and there is no analysis of the action level structure for this situation. At the same time, there is a lack of effective detection criteria and structures specifically for two commutation failures, which makes it difficult for the prior art to accurately detect and judge these complex commutation failures, thereby affecting the safe, stable and efficient operation of the HVDC system.

[0097] In summary, the existing technology has the problem of insufficient accuracy in commutation failure detection, which is mainly reflected in the limited ability to detect commutation failures with atypical characteristics and the imperfect detection method for multiple commutation failures. This brings potential risks and challenges to the stable operation of HVDC systems.

[0098] The present invention provides a high-voltage DC commutation failure detection scheme that is adaptable to multiple types of valve-side current characteristics in different time intervals, accurately determines the time intervals of three types of commutation failures and the dynamic change characteristics of their respective valve-side currents, and accurately proposes effective detection criteria and structures. It has universal applicability for the detection of commutation failures in various DC projects. Compared with actual engineering schemes and existing technologies, the present invention has greater advantages in detection reliability, sensitivity and commutation failure type identification capabilities.

[0099] See also Figure 1 , Figure 1 A flowchart of a method for detecting high voltage direct current commutation failures that is adaptable to multiple types of embodiments of the present invention is provided.

[0100] The present invention provides a method for detecting high voltage direct current commutation failures that is adaptable to multiple types, comprising:

[0101] Step 101: respond to a commutation detection request for a target system, and obtain a valve-side current waveform and commutation characteristic data of the target system.

[0102] The target system refers to the high voltage direct current transmission system.

[0103] The commutation detection request refers to a detection request instruction initiated to determine whether the commutation process in the high-voltage direct current transmission system is normal.

[0104] Valve side current waveform, a graph showing the current flowing through one side of the converter valve changing with time.

[0105] The commutation characteristic data refers to relevant data that can reflect the characteristics of the commutation process in the target system, including but not limited to the steady-state commutation angle, the steady-state triggering angle, the steady-state triggering phase interval, the first commutation valve pre-sensor angle and the second commutation valve pre-sensor angle.

[0106] In an embodiment of the present invention, in response to a received detection request instruction initiated for determining whether a commutation process in a high-voltage direct current transmission system is normal, a valve-side current waveform of a current flowing through one side of a converter valve of a target system that varies with time, and commutation characteristic data reflecting the characteristics of the commutation process in the target system are obtained.

[0107] Step 102: Determine a commutation result based on the valve-side current waveform and a preset commutation failure criterion.

[0108] Presetting a commutation failure criterion means obtaining a valve-side current waveform of a commutation failure by analyzing a valve-side current relationship of a converter transformer of a commutation failure in advance, and then analyzing the valve-side current waveform of a commutation failure to obtain an auxiliary criterion of a commutation failure.

[0109] In the embodiment of the present invention, according to the primary commutation failure criterion obtained by pre-analysis, the valve-side current waveform of the target system acquired in real time is analyzed, so as to obtain the primary commutation result of the target system.

[0110] Step 103: When a commutation result is a commutation failure, two commutation failure intervals are determined based on the commutation failure moment and commutation characteristic data of the commutation failure.

[0111] The two commutation failure interval refers to the time period when two commutation failures occur during system operation. This time period can be divided into two types according to the order and interval of the two commutation failures: two continuous commutation failure interval and two discontinuous commutation failure interval.

[0112] Two consecutive commutation failure intervals refer to the situation where two commutation failures occur successively within a short period of time without successful commutation in between.

[0113] The two discontinuous commutation failure interval refers to the situation where there is a successful commutation between the two commutation failures.

[0114] In the embodiment of the present invention, two consecutive commutation failure intervals and two discontinuous commutation failure intervals are determined according to the commutation failure moment of a commutation failure in combination with the commutation characteristic data.

[0115] Step 104: Determine the two commutation results based on the two commutation failure intervals, the valve-side current waveform and the preset two commutation failure criteria.

[0116] The preset two-phase commutation failure criterion refers to obtaining the valve-side current waveform of the two-phase commutation failure by analyzing the valve-side current relationship of the converter transformer with two-phase commutation failures in advance, and then analyzing the valve-side current waveform of the two-phase commutation failures to obtain the auxiliary criterion of the two-phase commutation failure, which is divided into two types: two-phase continuous commutation failure criterion and two-phase discontinuous commutation failure criterion.

[0117] The two consecutive commutation failure criterion refers to the basis or standard for determining whether two consecutive commutation failures have occurred in a high-voltage direct current transmission system.

[0118] The double discontinuous commutation failure criterion refers to the basis or standard for determining whether double discontinuous commutation failures have occurred in a high voltage direct current transmission system.

[0119] In the embodiment of the present invention, the valve-side current waveform is analyzed according to the two commutation failure intervals and the preset two commutation failure criteria, so as to obtain the two commutation results of the target system.

[0120] In the present invention, in response to a commutation detection request for a target system, a valve-side current waveform and commutation characteristic data of the target system are obtained; a commutation result is determined based on the valve-side current waveform and a preset commutation failure criterion; when a commutation result is a commutation failure, a two-commutation failure interval is determined based on the commutation failure moment of the one-commutation failure and the commutation characteristic data; two-commutation results are determined based on the two-commutation failure interval, the valve-side current waveform and the preset two-commutation failure criterion; the present invention first analyzes the valve-side current waveform of the target system through a one-commutation failure criterion obtained by pre-analysis to accurately obtain a commutation result, and then determines the two-commutation failure interval according to the commutation failure moment of the one-commutation failure, and finally obtains the two-commutation results in combination with the two-commutation failure criterion obtained by pre-analysis. The present invention can accurately identify the results of different types of commutation in a high-voltage direct current transmission system, accurately determine whether different commutation failure situations occur, and improve the operating stability of the high-voltage direct current transmission system.

[0121] See also Figure 2 , Figure 2 A flowchart of a method for detecting high voltage direct current commutation failures applicable to multiple types of applications is provided in accordance with a second embodiment of the present invention.

[0122] The present invention provides a method for detecting high voltage direct current commutation failures that is adaptable to multiple types, comprising:

[0123] Step 201: respond to a commutation detection request for a target system, and obtain a valve-side current waveform and commutation characteristic data of the target system.

[0124] In the embodiment of the present invention, the specific implementation process of step 201 is similar to step 101 and will not be repeated here.

[0125] Further, the preset one-phase commutation failure criterion includes an atypical commutation failure criterion and a typical commutation failure criterion. The preset two-phase commutation failure criterion includes two continuous commutation failure criterion and two discontinuous commutation failure criterion.

[0126] It is worth mentioning that the present invention obtains valve-side current relationship and waveform under various commutation failure types. By analyzing the valve-side current relationship of the converter transformer with one commutation failure, two consecutive commutation failures and two discontinuous commutation failures, the valve-side current waveform under commutation failure is obtained. The following analysis shows that the converter valve V1 y To V3 y Commutation failure process:

[0127] (1) Obtaining the current waveform of the valve side when a commutation failure occurs

[0128] Process 1: When u yba In the positive half axis and V3 y When receiving the trigger pulse signal, V1 y Start to V3 y Before i1 drops to 0, V1 y , V2 y and V3 y Simultaneous conduction:

[0129] (1)

[0130] (2)

[0131] Where, L T Indicates the commutation reactance converted to the valve side, i a ,i b ,i c They represent the three-phase valve-side current, which flows from the converter valve to the AC system, I d Indicates direct current, u yba Indicates the commutation voltage.

[0132] Process 2: u yba When V1 crosses zero in the negative direction, y Still not turned off or the remaining carriers are not exhausted after turning off, V1 y Will continue or turn on again due to the forward voltage, V3 y It starts to shut down when it is subjected to reverse voltage. yba From negative zero crossing to V4 y Before conduction, the current relationship can still be expressed by equations (1) and (2), but its initial value is different from that in process 1.

[0133] Process 3: V1 y To V3 y The phase switching process has not yet ended, V2 of the common anode group y Started to V4 y Phase change, at this time V1 y , V2 y , V3 y and V4 y Simultaneous conduction:

[0134] (3)

[0135] (4)

[0136] Process 4: V4 y Whether the trigger is early and the degree of early triggering will affect V2y and V3 y The shutdown sequence.

[0137] Case 1: V4 y When triggered, V1 y To V3 y The switching phase is almost over, i3 has been decaying for a long time, V3 y Before V2 y Shutdown. V3 y After shutdown to V2 y Before shutting down, V1 y , V2 y and V4 y Simultaneous conduction:

[0138] (5)

[0139] (6)

[0140] Case 2: V1 y To V3 y V4 at the beginning of phase switching or even before phase switching y It has been triggered, V2 y Before V3 y Shutdown. V2 y After shutdown to V3 y Before shutting down, V1 y , V3 y and V4 y Simultaneous conduction:

[0141] (7)

[0142] (8)

[0143] Process 5: V1 only y and V4 y Conductive, DC side short circuit:

[0144] (9)

[0145] According to V4 y The degree of early triggering can obtain two typical characteristics and one atypical characteristic of the valve side current waveform of a commutation failure, such as Figure 3-Figure 5 shown.

[0146] Figure 3 A schematic diagram of the valve-side current waveform showing the first typical characteristic of a commutation failure;

[0147] Figure 4 A schematic diagram of the valve-side current waveform showing the second typical characteristic of a commutation failure;

[0148] Figure 5 A schematic diagram of the valve-side current waveform with atypical characteristics of a commutation failure;

[0149] In the figure, i s Indicates steady-state current, on means conduction, and off means shutdown. yba The positive zero-crossing phase is the reference phase "0". Normally, V3 y The trigger phase is 142°, V4 y The trigger phase is 202°. Figure 3 The triggering phase of V4y is 200°, and the degree of early triggering is very small; Figure 4 Medium V4 y The trigger phase is 180°, and the degree of advance triggering is relatively large. Figure 5 Medium V4 y The trigger phase is 189°, where V2 y and V3 y The turn-off phase interval is about 4°.

[0150] (2) Obtaining the valve-side current waveform after two consecutive commutation failures

[0151] Two consecutive commutation failures means that at V1 y To V3 y Commutation failure based on V2 y To V4 y Commutation failure. Two consecutive commutation failures are mostly based on the development of a commutation failure process 4 situation 1. The subsequent process is as follows:

[0152] Process 5: -u yac When V2 crosses zero in the negative direction y Still not turned off or the remaining carriers are not exhausted after turning off, V2 y Will continue or turn on again due to the forward voltage, V4 y When subjected to reverse voltage, it starts to turn off:

[0153] (10)

[0154] (11)

[0155] Process 6: V6 y After conduction, V4 y and V5 y Will shut down in sequence:

[0156] (12)

[0157] (13)

[0158] Process 7: V5 y Shutdown to V6 y Before shutdown, V1 y , V2 y and V6 y Simultaneous conduction:

[0159] (14)

[0160] (15)

[0161] Process 8: V6 y Shut down, only V1 remains y and V2 y Continuity:

[0162] (16)

[0163] The valve side current waveform after two consecutive commutation failures is as follows: Figure 6 As shown, Figure 6 Schematic diagram of valve-side current waveform after two consecutive commutation failures.

[0164] (3) Obtaining the valve-side current waveform of two discontinuous commutation failures

[0165] Two discontinuous commutation failures mean that at V1 y To V3 y Commutation failure based on V2 y To V4 y Successful commutation, V4 y To V6 y Commutation failure. Two discontinuous commutation failures are mostly based on the development of a commutation failure process 4 situation 1. The first commutation failure is consistent with the first commutation failure process. The subsequent process is as follows:

[0166] Process 6: V1 y To V3 y Phase switching forces V3 y After shutdown, V5 y The commutation voltage is given by u ycb becomes u yca , V5 y The conduction conditions are: (1) the potential at point c is higher than the potential at point a; (2) V5 y The trigger pulse has been generated:

[0167] Case 1: V5 y Continuity:

[0168] (17)

[0169] (18)

[0170] Case 2: V5 y No Continuity:

[0171] (19)

[0172] Process 7: V6 y Conduct to V2 y Before conduction, V1 y , V4 y and V6 y Simultaneous conduction:

[0173] (20)

[0174] (twenty one)

[0175] Process 8: V2 y Is it in V6 y The conduction before shutdown affects the subsequent commutation circuit:

[0176] Case 1: V1 y , V2 y , V4 y and V6 y Simultaneous conduction:

[0177] (twenty two)

[0178] (twenty three)

[0179] Case 2: V6 y V2 before shutdown y Not conducting, only V1 y and V4 y Conductive, DC side short-circuited.

[0180] Process 9: Regardless of the situation in process 8, it is V1 at this time y , V2 y and V4 y When the switch is turned on, the current relationship is consistent with equations (17) and (18).

[0181] Process 10: V1 only y and V4 y Conductive, DC side short circuit:

[0182] (twenty four)

[0183] The valve side current waveform after two discontinuous commutation failures is as follows Figure 7 As shown, Figure 7 Schematic diagram of valve-side current waveform with two discontinuous commutation failures.

[0184] Step 202: When the valve-side current waveform satisfies the atypical commutation failure criterion, it is determined that an atypical commutation failure occurs in the target system.

[0185] According to the above process, the atypical commutation failure criterion is obtained:

[0186] During a commutation failure with atypical characteristics, from V3 y The conduction to bypass pair appears, i a In the negative half axis, it gradually increases to 0. b In the negative half axis, it first decays to a minimum value and then increases to 0. It constitutes an auxiliary criterion for a commutation failure:

[0187] (1) The valve-side current of the AC phase of the converter valve that fails to shut down (referred to as “i x ”) shows an increasing trend on the negative half axis, and the increasing magnitude is greater than the current threshold I1 (the preset first current threshold);

[0188] (2) The valve-side current of the AC phase of the converter valve that is forced to shut down (referred to as “i y ”, its lag i x Phase 120°) has a minimum point on the negative semi-axis;

[0189] (3) i y After the minimum value, it shows an increasing trend, and the increasing amount is greater than the current threshold I2 (the preset second current threshold).

[0190] Further, step 202 may include the following sub-steps:

[0191] S11, obtaining a first-phase valve-side current waveform and a second-phase valve-side current waveform when the valve-side current is a negative value in the valve-side current waveform.

[0192] S12, determining whether the first phase valve side current waveform has an increasing trend.

[0193] S13: When the first phase valve side current waveform has an increasing trend, determine whether the increasing trend is greater than a preset first current threshold.

[0194] S14: When the increasing trend is greater than the preset first current threshold, it is determined that the first commutation failure feature exists.

[0195] S15, determining whether the second phase valve side current waveform has a minimum value.

[0196] S16. When the second phase valve side current waveform has a minimum value, it is determined that the second commutation failure feature exists.

[0197] S17, determining whether the increasing trend of the second phase valve side current waveform is greater than a preset second current threshold after the second phase valve side current waveform reaches a minimum value.

[0198] S18. When the increasing trend of the second phase valve side current waveform is greater than the preset second current threshold, it is determined that the third commutation failure feature exists.

[0199] S19. When the valve-side current waveform has the first commutation failure characteristic, the second commutation failure characteristic and the third commutation failure characteristic at the same time, it is determined that an atypical commutation failure occurs in the target system.

[0200] For easier understanding, see Figure 8-Figure 9 , the atypical commutation failure detection logic of steps S11-S19 is as follows:

[0201] See also Figure 8 , Figure 8 The valve side current i is the first phase valve side current waveform x Schematic diagram of the judgment logic;

[0202] See also Fig. 9 , Fig. 9 The valve side current i is the second phase valve side current waveform y Schematic diagram of the judgment logic;

[0203] Figure 8-Figure 9 In, L incx and L incy Respectively reflect i x and i y Whether the level signal is increasing, L decy It reflects y Whether to attenuate the level signal, P incx and P incy They are respectively incx and L incy The pulse signal of the rising edge, i rx and i ry I x and i y The initial value of the increment, L rx is the level signal reflecting the auxiliary criterion (1), L miny is the level signal reflecting the auxiliary criterion (2), L ry It reflects y The level signal meets the increasing requirement on the negative half axis.

[0204] See also Figure 8 ,i x The specific control steps of the judgment are as follows:

[0205] 1. Input the valve-side current of the converter transformer to determine whether it is increasing. If it is increasing, output an increasing signal;

[0206] 2. Detect the rising edge of the increasing signal, and output a pulse signal when the rising edge comes;

[0207] 3. Record the valve side current i at the moment of the pulse signal x The value of i rx ;

[0208] 4. Input i x with i rx The difference is determined to determine whether the difference is greater than a threshold value. If so, a high level signal is output;

[0209] 5. Judgement i x Is it less than 0? If so, output a high level signal;

[0210] 6. Take the logical AND of the high-level signals in 4 and 5, widen them, and output the level signal of the auxiliary criterion (1).

[0211] See also Fig. 9 ,i y The specific control steps of the judgment are as follows:

[0212] 1. Input the valve side current of the converter transformer to determine whether it is increasing or decreasing. If it is increasing, output an increasing signal; if it is decreasing, output a decreasing signal;

[0213] 2. Input the increasing signal and the attenuation signal to determine whether the valve side current has a minimum value. If so, output the level signal and widen it to obtain the level signal L reflecting the auxiliary judgment criterion (2). miny ;

[0214] 3. Detect the rising edge of the increasing signal, and output a pulse signal when the rising edge comes;

[0215] 4. Record the valve side current i at the moment of the pulse signal y The value of L ry ;

[0216] 5. Input i y With L ry The difference is determined to determine whether the difference is greater than a threshold value. If so, a high level signal is output;

[0217] 6. Judgement y Is it less than 0? If so, output a high level signal;

[0218] 7. Take the logical AND of the high-level signals in 4 and 5, and widen them. The output reflects i y The level signal L that meets the increasing requirement on the negative half axis ry .

[0219] In the embodiment of the present invention, when i is detected xWhen the negative half axis increases and the increment is greater than the threshold, L rx Converted to high level; when detected i y When there is a minimum point on the negative semi-axis, L miny Converted to high level; when detected i y When the negative half axis increases and the increase is greater than the threshold, L ry Converted to high level; when L rx , L miny and L ry When both are at a high level, the first atypical commutation failure is detected.

[0220] Step 203: When the valve-side current waveform meets the typical commutation failure criterion, it is determined that a typical commutation failure occurs in the target system.

[0221] Typical commutation failure criterion refers to the standard or basis for determining whether a typical commutation failure occurs in a high-voltage direct current transmission system.

[0222] It should be noted that the valve-side current waveform is one of the important bases for determining a typical commutation failure. When a typical commutation failure occurs, the valve-side current waveform will show obvious abnormal characteristics.

[0223] In the embodiment of the present invention, the valve-side current waveform of the target system is obtained in real time, and it is judged whether the commutation characteristics in the valve-side current waveform meet the commutation failure characteristics in the typical commutation failure criterion, wherein the typical commutation failure criterion is obtained by analyzing the valve-side current waveform of the above-mentioned commutation failure:

[0224] The first typical commutation failure criterion:

[0225] 1) The valve-side current of the AC phase of the converter valve that failed to shut down (referred to as “i x ”) It shows an increasing trend on the negative semi-axis; 2) When it increases to a value close to zero but less than zero, it begins to decay on the negative semi-axis; 3) It then quickly turns to increasing and finally increases to zero on the negative semi-axis.

[0226] The second typical commutation failure criterion:

[0227] 1) The valve-side current of the AC phase of the converter valve that failed to shut down (referred to as “i x ”) It shows an increasing trend on the negative half axis; 2) When it increases to a value close to zero but less than zero, it crosses the zero value in a short period of time and rapidly increases to a certain value on the positive half axis; 3) It then rapidly turns to attenuation and finally decays to zero.

[0228] Through the above two typical commutation failure criteria, it is possible to determine whether a typical commutation failure and the type of a typical commutation failure occur in the target system. The typical commutation failure detection logic here is similar to the atypical commutation failure detection logic, which will not be repeated here.

[0229] Step 204: When there is no atypical commutation failure or a typical commutation failure, it is determined that a commutation result is that no commutation failure occurs.

[0230] In the embodiment of the present invention, when there is no atypical commutation failure or typical commutation failure, that is, there is no atypical commutation failure and no typical commutation failure, it is determined that a commutation result is that no commutation failure occurs.

[0231] Step 205: When there is an atypical commutation failure or a typical commutation failure, a commutation result is determined to be a commutation failure.

[0232] In the embodiment of the present invention, when there is an atypical commutation failure or a typical commutation failure, that is, when there is any one of an atypical commutation failure and a typical commutation failure, a commutation result is determined to be the occurrence of a commutation failure.

[0233] Step 206: When a commutation result is a commutation failure, two commutation failure intervals are determined based on the commutation failure moment and commutation characteristic data of the commutation failure.

[0234] Further, the commutation characteristic data includes a steady-state commutation angle, a steady-state trigger angle, a steady-state trigger phase interval, a first converter valve pre-touch angle, and a second converter valve pre-touch angle, and the two commutation failure intervals include two continuous commutation failure intervals and two discontinuous commutation failure intervals. Step 206 may include the following sub-steps:

[0235] S21. Determine the lower limit of two consecutive commutation failure intervals by using the commutation failure moment and the steady-state commutation angle.

[0236] The lower limit of the interval between two consecutive commutation failures is encapsulated into a calculation formula, as follows:

[0237]

[0238] In the formula, Indicates the lower limit of the interval between two consecutive commutation failures. Indicates the moment of commutation failure. represents the steady-state commutation angle, specifically 23°.

[0239] S22. Determine an upper limit value of two consecutive commutation failure intervals by using the commutation failure moment and the steady-state trigger angle.

[0240] The upper limit value of the interval between two consecutive commutation failures is encapsulated into a calculation formula, as follows:

[0241]

[0242] In the formula, Indicates the upper limit of the interval between two consecutive commutation failures. Represents the steady-state firing angle, specifically 142°.

[0243] In the embodiment of the present invention, the time when a commutation failure occurs is determined by step 205, that is, when there is any one of an atypical commutation failure and a typical commutation failure, the time corresponding to the first pulse signal sent is the time when a commutation failure occurs. The time when a commutation failure occurs is t cf , considering that the phase interval from the start to the end of the first switching phase is 23°, the time interval is 1.28ms, 1.28ms corresponds to 23°, and the steady-state switching angle is 23°. Even if we optimistically consider that a switching failure detection signal is issued at the beginning of the first switching phase, t cf At +0.00128s, the next converter valve is also turned on. After the next converter valve is turned on, x It shows an increasing trend. Conservatively assuming that V6y is not triggered in advance, then V6 y Conducting distance V1 y To V3 y The conservative phase interval of the switching start point is 142°, the corresponding time interval is 7.88ms, 7.88ms corresponds to 142°, and the steady-state trigger angle is 142°. Therefore, t∈[t cf +0.00128s, t cf +0.00788s] can effectively distinguish the first and second commutation failures and will not affect the detection of the second commutation failure. cf +0.00128s, t cf +0.00788s] time interval, if i is detected x If there is a maximum value, it must mean that the second commutation failure occurs.

[0244] S23, using the commutation failure moment, the steady-state trigger angle and the first converter valve pre-touch angle to determine the lower limit value of two discontinuous commutation failure intervals.

[0245] The lower limit of the interval between two discontinuous commutation failures is encapsulated into a calculation formula, as follows:

[0246]

[0247] In the formula, Indicates the lower limit of the interval between two discontinuous commutation failures. Indicates the pre-sensor angle of the first converter valve, specifically V6 y The angle of early triggering is 30°.

[0248] S24, using the commutation failure moment, the steady-state trigger phase interval, the steady-state trigger angle and the second converter valve pre-touch angle to determine the upper limit value of the interval between two discontinuous commutation failure intervals.

[0249] The upper limit value of the interval between two discontinuous commutation failure intervals is encapsulated into a calculation formula, as follows:

[0250]

[0251] In the formula, Indicates the upper limit of the interval between two discontinuous commutation failures. Indicates the steady-state trigger phase interval, specifically refers to the 6-pulse converter steady-state trigger phase interval, 60°, Indicates the pre-sensor angle of the second converter valve, specifically V2 y The angle of the advance trigger, 40°, 5 means V2 y The positive zero crossing point of the commutation voltage is V3 y There are 5 trigger phase intervals between the positive zero crossing points of the commutation voltage.

[0252] In the embodiment of the present invention, it is conservatively considered that the response delay of a commutation failure detection signal is about 1.5ms, and usually after a commutation failure, the control system will generate a trigger pulse for the subsequent commutation valve in advance. y is triggered 30° in advance, then V6 y The fastest possible time for conduction is about 5ms after the first commutation failure detection signal is issued. The early trigger time margin considered here will not cause misjudgment of detection, because in the case of two discontinuous failures, the first bypass pair appears to V6 y Before being triggered, i a is always non-negative.

[0253] In addition, without considering the phase shift of the commutation voltage, V6 y When the phase is 360°, it starts to bear the reverse voltage. At this time, the distance V1 y To V3 y The time interval of the phase switching starting point is 10ms. y When subjected to reverse voltage, i a In the negative half axis, it increases greatly from the minimum value.

[0254] Optimistic Consideration V2 y Triggered 40° in advance, i.e. V2 y When the phase is 402°, V2 y The trigger phase is related to V1 y To V3 y The phase interval at the starting point of the phase switching is 222°, and the corresponding time interval is 12.33ms. Therefore, the time interval between two discontinuous switching failures is t∈[tcf +0.005s, t cf +0.01233s].

[0255] See also Fig.10 , Fig.10 A schematic diagram of obtaining the action level of two commutation failures in different time intervals;

[0256] In the figure, P CF and L CF are the detection pulse and the widening level of a commutation failure, respectively; Time is the running time of the system; L con It is a level signal reflecting the time interval of two consecutive commutation failures. incon It is a level signal reflecting the time interval between two discontinuous commutation failures.

[0257] The specific control steps are as follows:

[0258] 1. Input the system operation time and a commutation failure pulse signal, sample the system operation time, the sampling pulse is a commutation failure pulse signal, and the sampling time is the commutation failure time;

[0259] 2. Send the time of a commutation failure to the time interval upper and lower limit calculation module, and output the upper and lower limit values ​​of two continuous and two discontinuous commutation failure time intervals;

[0260] 3. Compare the time interval limit with the system operating time, and output the time interval level of two consecutive commutation failures and the time interval level of two discontinuous commutation failures.

[0261] Step 207: Determine the two commutation results based on the two commutation failure intervals, the valve-side current waveform and the preset two commutation failure criteria.

[0262] Further, the preset two commutation failure criteria include two continuous commutation failure criteria and two discontinuous commutation failure criteria, and step 207 may include the following sub-steps:

[0263] S31. Determine two consecutive commutation results based on two consecutive commutation failure intervals, valve-side current waveforms, and two consecutive commutation failure criteria.

[0264] The detection criteria and structure of two consecutive commutation failures are as follows:

[0265] The detection criteria for two consecutive commutation failures are:

[0266] (1) At t cf A commutation failure signal is detected at all times;

[0267] (2) At t∈[t cf+0.00128s, t cf +0.00788s] time interval, i x On the negative half axis, it shows a trend of first increasing to a maximum point and then decaying, and the decay amplitude is greater than I3 (the preset third current threshold); 0.05kA is directly used instead of I3.

[0268] (3) i x +i z <ε, ε is slightly greater than 0. z (The first phase valve side current is the first conversion phase valve side current under the transformation coordinate) leading i x Phase 120°.

[0269] i x 、i y 、i z represents the three-phase current on the valve side of the converter transformer. They are in relative transformation coordinates, for example: i x for i a ,i y for i b ,i z for i c ;i x for i b ,i y for i c ,i z for i a .

[0270] Further, S31 may include the following sub-steps:

[0271] S311. When a commutation failure is detected, determine whether the operation time of the target system is within an interval of two consecutive commutation failures.

[0272] S312: When the operation time of the target system is within the interval of two consecutive commutation failures, it is determined that a fourth commutation failure feature exists.

[0273] S313, determine whether the first phase valve side current waveform has an increasing trend.

[0274] S314: When the first-phase valve-side current waveform has an increasing trend, determine whether the first-phase valve-side current waveform has a maximum value.

[0275] S315. When the first-phase valve-side current waveform has a maximum value, determine whether the first-phase valve-side current waveform has a decay trend after the increasing trend reaches the maximum value.

[0276] S316: When the increasing trend of the first-phase valve-side current waveform reaches a maximum value and then has a decaying trend, it is determined that the fifth commutation failure feature exists.

[0277] S317: Determine whether the attenuation trend is greater than a preset third current threshold.

[0278] S318: When the attenuation trend is greater than the preset third current threshold, it is determined that the sixth commutation failure feature exists.

[0279] S319, obtaining a first-phase valve-side current waveform of a first-phase valve-side current, in which the first-phase valve-side current is in a first-transformed phase valve-side current under transformed coordinates.

[0280] S3110, performing a sum operation on the first phase valve side current and the first conversion phase valve side current to generate a first sum.

[0281] S3111. Determine whether the first sum is less than a preset first sum threshold.

[0282] S3112: When the first sum value is less than the preset first sum value threshold, it is determined that the seventh commutation failure feature exists.

[0283] S3113. When the valve-side current waveform does not simultaneously have the fourth commutation failure characteristic, the fifth commutation failure characteristic, the sixth commutation failure characteristic and the seventh commutation failure characteristic, it is determined that the target system has not had two consecutive commutation failures, and it is determined that the eighth commutation failure characteristic exists.

[0284] S3114. When the valve-side current waveform simultaneously has the fourth commutation failure characteristic, the fifth commutation failure characteristic, the sixth commutation failure characteristic and the seventh commutation failure characteristic, it is determined that the target system has two consecutive commutation failures.

[0285] For easier understanding, see Figure 11-Figure 12 The logic of two consecutive commutation detections in steps S311-S3114 is as follows:

[0286] In the figure, L decx It reflects x Whether to attenuate the level signal, P decx Is a reflection of L decx The rising edge pulse signal, L dx It reflects x Whether the level signal meets the attenuation requirement in the negative half axis, i dx is i x Initial value of attenuation, L maxx It reflects x Is there a maximum level signal, L subcon It reflects x +i z <ε level signal, L CFcon It is the detection signal of two consecutive commutation failures.

[0287] Fig.11 The valve side current i is the first phase valve side current waveformx Schematic diagram of attenuation criterion;

[0288] Fig.12 It is a schematic diagram of obtaining detection signals of two consecutive commutation failures;

[0289] See also Fig.11 , the specific control steps of attenuation criterion are as follows:

[0290] 1. Input the valve side current of the converter transformer to determine whether it is attenuated. If so, output an attenuation signal;

[0291] 2. Detect the rising edge of the attenuation signal, and output a pulse signal when the rising edge comes;

[0292] 3. Record the valve side current i at the moment of the pulse signal x The value of i dx ;

[0293] 4. Input i dx with i x The difference is determined to determine whether the difference is greater than a threshold value. If so, a high level signal is output;

[0294] 5. Judgement i x Is it less than 0? If so, output a high level signal;

[0295] 6. Take the logical AND of the high-level signals in 4 and 5, and widen them. The output reflects i x Attenuated level signal L dx .

[0296] See also Fig.12 , the specific control steps for obtaining the detection signal of two consecutive commutation failures are as follows:

[0297] 1. Input the valve side current of the converter transformer to determine whether it is increasing or decreasing. If it is increasing, output an increasing signal; if it is decreasing, output a decreasing signal;

[0298] 2. Input the attenuated signal and the widened increasing signal. Through logical AND judgment, if the two signals have a high-level intersection, the output reflects i x There is a maximum level signal L maxx ;

[0299] 3. Judgement x with i z Is the modulus of the sum less than the threshold? If so, output the level signal L reflecting the detection criterion (3) of two consecutive commutation failures subcon ;

[0300] 4. Input L maxx , L subcon 、Reflection x Attenuated level signal Ldx And the action level L of two consecutive commutation failure time interval con , the four signals are judged by logic and, if the four signals have a high-level intersection, the output reflects the detection signal L of the two commutation failures CFcon .

[0301] In the embodiment of the present invention, when the first commutation failure is detected and Time belongs to the time interval of two consecutive commutation failures, L con Converted to high level; when detected i x When the negative half axis shows the characteristic of increasing to a maximum value first and then decaying, L maxx Converted to high level; when detected i x When the attenuation amplitude of the negative half axis is greater than the threshold, L dx Converted to high level; when detected i x +i z When <ε, L subcon Converted to high level; when L con , L maxx , L dx and L subcon At the same time, when it is at high level, L CFcon Transitioning to high level means that two consecutive commutation failures have been detected.

[0302] S32. Determine two discontinuous commutation results based on two continuous commutation failure intervals, two discontinuous commutation failure intervals, valve-side current waveforms, and two discontinuous commutation failure criteria.

[0303] Two discontinuous commutation failure detection criteria and structure:

[0304] The detection criteria for two discontinuous commutation failures are:

[0305] (1) At t cf A commutation failure signal is detected at all times;

[0306] (2) In the time interval t∈[t cf +0.00128s, t cf +0.00788s], no two consecutive commutation failure signals were detected;

[0307] (3) At t∈[t cf +0.005s, t cf +0.01233s] time interval, i x On the negative half axis, it first decays to a minimum value and then increases significantly;

[0308] (4) i x +i y <ε, ε is slightly greater than 0.

[0309] Further, S32 may include the following sub-steps:

[0310] S321. When a commutation failure is detected, determine whether the operation time of the target system is within an interval of two discontinuous commutation failures.

[0311] S322: When the operation time of the target system is within the interval of two discontinuous commutation failures, it is determined that a ninth commutation failure feature exists.

[0312] S323, determine whether the first phase valve side current waveform has a decay trend.

[0313] S324. When the first-phase valve-side current waveform has a decaying trend, determine whether there is an increasing trend after the decaying trend of the first-phase valve-side current waveform reaches a minimum value.

[0314] S325. When the attenuation trend of the first-phase valve-side current waveform reaches a minimum value and then has an increasing trend, it is determined that the tenth commutation failure feature exists.

[0315] S326: Determine whether the increasing trend is greater than a preset fourth current threshold.

[0316] S327: When the increasing trend is greater than the preset fourth current threshold, it is determined that the eleventh commutation failure feature exists.

[0317] S328, performing a sum operation on the first-phase valve-side current of the first-phase valve-side current waveform and the second-phase valve-side current of the second-phase valve-side current waveform to generate a second sum.

[0318] S329: Determine whether the second sum is less than a preset second sum threshold.

[0319] S3210: When the second sum is less than the preset second sum threshold, it is determined that the twelfth commutation failure feature exists.

[0320] S3211. When the valve-side current waveform does not simultaneously have the ninth commutation failure characteristic, the tenth commutation failure characteristic, the eleventh commutation failure characteristic and the twelfth commutation failure characteristic, or has the eighth commutation failure characteristic, it is determined that the target system has not experienced two discontinuous commutation failures.

[0321] S3212: When the valve-side current waveform simultaneously has the ninth commutation failure characteristic, the tenth commutation failure characteristic, the eleventh commutation failure characteristic and the twelfth commutation failure characteristic, and does not have the eighth commutation failure characteristic, it is determined that the target system has two discontinuous commutation failures.

[0322] For easier understanding, see Fig.13 The logic of the two discontinuous commutation detections in steps S321-S3212 is as follows:

[0323] Fig.13 It is a schematic diagram of obtaining two discontinuous commutation failure detection signals;

[0324] In the figure, L minx It reflects x Is there a minimum level signal, L subincon It reflects x +i y <ε level signal, L CFincon It is the detection signal of two discontinuous commutation failures.

[0325] Specific control steps for obtaining two discontinuous commutation failure detection signals:

[0326] 1. Input the valve side current of the converter transformer to determine whether it is increasing or decreasing. If it is increasing, output an increasing signal; if it is decreasing, output a decreasing signal;

[0327] 2. Input the increasing signal and the widened attenuated signal. Through logical AND judgment, if the two signals have a high-level intersection, the output reflects i x There is a minimum level signal L minx ;

[0328] 3. Judgement x with i y Is the modulus of the sum less than the threshold? If so, output the level signal L reflecting the two discontinuous commutation failure detection criterion (4) subincon ;

[0329] 4. Input L minx , L subincon 、Reflection x Increasing level signal L rx And the action level L of two discontinuous commutation failure time interval CFincon , the four signals are judged by logic and if there is a high-level intersection among the four signals, a high-level signal is output;

[0330] 5. Input the detection signal of two commutation failures, invert it after widening, and make a logical AND judgment with the output signal in 4. If the two signals have a high-level intersection, the output reflects the detection signal L of two commutation failures. CFincon .

[0331] In the embodiment of the present invention, when the first commutation failure is detected and Time belongs to the time interval of two discontinuous commutation failures, L incon Converted to high level; when detected i x When the negative half axis shows the characteristic of first decaying to a minimum value and then increasing, L minx Converted to high level; when detected i xWhen the increment of the negative half axis is greater than the threshold, L rx Converted to high level; when detected i x +i y When <ε, L subincon When L incon , L minx , L rx and L subincon At the same time, L CFcon When at low level, L CFincon Transitioning to high level means that two discontinuous commutation failures have been detected.

[0332] In the present invention, in response to a commutation detection request for a target system, a valve-side current waveform and commutation characteristic data of the target system are obtained; a commutation result is determined based on the valve-side current waveform and a preset commutation failure criterion; when a commutation result is a commutation failure, a two-commutation failure interval is determined based on the commutation failure moment of the one-commutation failure and the commutation characteristic data; two-commutation results are determined based on the two-commutation failure interval, the valve-side current waveform and the preset two-commutation failure criterion; the present invention first analyzes the valve-side current waveform of the target system through a one-commutation failure criterion obtained by pre-analysis to accurately obtain a commutation result, and then determines the two-commutation failure interval according to the commutation failure moment of the one-commutation failure, and finally obtains the two-commutation results in combination with the two-commutation failure criterion obtained by pre-analysis. The present invention can accurately identify the results of different types of commutation in a high-voltage direct current transmission system, accurately determine whether different commutation failure situations occur, and improve the operating stability of the high-voltage direct current transmission system.

[0333] The following provides a specific simulation verification example:

[0334] 1. DC engineering model 1 simulation verification

[0335] Simulation condition 1: When the system runs to 3.992s, a three-phase ground fault with a fault inductance of 0.04H and lasting for 0.1s occurs in the AC system. The response of the commutation failure detection link is as follows: Fig.14 As shown, Fig.14 It is a schematic diagram of the response of the commutation failure detection link during three-phase fault of DC engineering model 1.

[0336] Simulation condition 2: When the system runs for 4 seconds, a ground fault occurs in phase A with a fault inductance of 0.01H and lasts for 0.1s. The response of the commutation failure detection link is as follows: Fig.15 As shown, Fig.15 This is a schematic diagram of the response of the commutation failure detection link when phase A fails in the DC engineering model 1.

[0337] where i Y and i DThey represent the valve-side current of YNy0 and YNd1 converter transformers respectively. Level=1 indicates the commutation failure detection link is activated. CF , L SCF_con and L SCF_in They represent the output signals of one, two continuous and two discontinuous commutation failure detection links, L CF_0 A detection signal representing a practical engineering solution.

[0338] Will Fig.14 and Fig.15 The trigger phase of the relevant valve, the response time of the commutation failure detection in the first power frequency cycle after the AC fault occurs, and the judgment result of the present invention are summarized in Table 1. Among them, the relevant valve refers to the first valve after the forced closing valve, and its phase reference point is the positive zero crossing point of the commutation voltage of the forced closing valve.

[0339] Combination Fig.14 , Fig.15 As shown in Table 1, in the DC engineering model 1, no matter it is a three-phase fault or a single-phase fault, the response time of the present invention for detecting commutation failure is obviously faster than that of the actual engineering solution, and the present invention can accurately identify the type of commutation failure.

[0340] Table 1. Commutation failure information of DC engineering model 1

[0341]

[0342] 2. DC Engineering Model 2 Simulation Verification

[0343] Simulation condition 3: When the system runs to 7.9933s, a ground fault occurs in phase C with a fault inductance of 0.04H and lasts for 0.1s. The response of the commutation failure detection link is as follows: Fig.16 As shown, Fig.16 This is a schematic diagram of the response of the commutation failure detection link when the C phase of the DC engineering model 2 fails.

[0344] Simulation condition 4: When the system runs for 8 seconds, a three-phase ground fault with a fault inductance of 0.07H and a duration of 0.1s occurs in the AC system. The response of the commutation failure detection link is as follows: Fig.17 As shown, Fig.17 This is a schematic diagram of the response of the commutation failure detection link during a three-phase fault in the DC engineering model 2.

[0345] Simulation condition 5: When the system runs for 8 seconds, a ground fault occurs in phase A with a fault inductance of 0.02H and lasts for 0.1s. The response of the commutation failure detection link is as follows: Fig.18 As shown, Fig.18 This is a schematic diagram of the response of the commutation failure detection link when phase A fails in DC engineering model 2.

[0346] Among them, LCF_1 and L CF_2 Respectively represent the detection signals of the prior art features 1 and 2, L CF_s A detection signal representing a phase-change failure auxiliary detection link of the present invention.

[0347] Fig.16 In the present invention, the prior art does not work, but the auxiliary detection link of a commutation failure can work reliably. Fig.17 and Fig.18 In all cases, the present invention can accurately identify the type of commutation failure. Figures 16 to 18 The trigger phase of the relevant valve, the response time of the commutation failure detection in the first power frequency cycle after the AC fault occurs, and the judgment result of the present invention are summarized in Table 2.

[0348] Combination Figure 16-Figure 18 As shown in Table 2, in DC engineering model 2, the present invention can solve the problem that the prior art does not operate under the characteristics of atypical primary commutation failure. At the same time, the response speed of the present invention is not slower than that of the actual engineering solution in most cases, and solves the problem that the actual engineering solution cannot identify the type of commutation failure.

[0349] Table 2. Commutation failure information of DC engineering model 2

[0350]

[0351] It should be noted that in Figure 14-18 In the figure, the Level on the vertical axis indicates the degree of response.

[0352] See also Fig.19 , Fig.19 This is a structural block diagram of a high-voltage direct current commutation failure detection system adapted to multiple types provided in Embodiment 3 of the present invention.

[0353] The present invention provides a high-voltage direct current commutation failure detection system that is adaptable to multiple types, comprising:

[0354] The response module 301 is used to respond to the commutation detection request for the target system and obtain the valve side current waveform and commutation characteristic data of the target system; the single commutation determination module 302 is used to determine the single commutation result based on the valve side current waveform and the preset single commutation failure criterion; the interval determination module 303 is used to determine the double commutation failure interval based on the commutation failure moment and commutation characteristic data of the single commutation failure when the single commutation result is a single commutation failure; the double commutation determination module 304 is used to determine the double commutation results based on the double commutation failure interval, the valve side current waveform and the preset double commutation failure criterion.

[0355] Further, the preset single-phase commutation failure criterion includes an atypical commutation failure criterion and a typical commutation failure criterion, and the single-phase commutation determination module 302 includes: an atypical commutation failure submodule, which is used to determine that an atypical commutation failure occurs in the target system when the valve-side current waveform meets the atypical commutation failure criterion; a typical commutation failure submodule, which is used to determine that a typical commutation failure occurs in the target system when the valve-side current waveform meets the typical commutation failure criterion; a first determination submodule, which is used to determine that a single-phase commutation result is that no single-phase commutation failure occurs when there is no atypical commutation failure or a typical commutation failure; and a second determination submodule, which is used to determine that a single-phase commutation result is that a single-phase commutation failure occurs when there is an atypical commutation failure or a typical commutation failure.

[0356] Furthermore, the atypical commutation failure submodule includes: a waveform acquisition unit, used to acquire the first phase valve side current waveform and the second phase valve side current waveform when the valve side current in the valve side current waveform is negative; a first judgment unit, used to judge whether the first phase valve side current waveform has an increasing trend; a second judgment unit, used to judge whether the increasing trend is greater than a preset first current threshold when the first phase valve side current waveform has an increasing trend; a third judgment unit, used to judge whether the first commutation failure feature exists when the increasing trend is greater than the preset first current threshold; a fourth judgment unit, used to judge whether the second phase valve side current waveform has a minimum value ; The fifth judgment unit is used to determine the presence of the second commutation failure feature when the second-phase valve-side current waveform has a minimum value; the sixth judgment unit is used to determine whether the increasing trend of the second-phase valve-side current waveform is greater than the preset second current threshold after the second-phase valve-side current waveform reaches the minimum value; the seventh judgment unit is used to determine the presence of the third commutation failure feature when the increasing trend of the second-phase valve-side current waveform is greater than the preset second current threshold; the eighth judgment unit is used to determine that an atypical commutation failure occurs in the target system when the valve-side current waveform has the first commutation failure feature, the second commutation failure feature and the third commutation failure feature at the same time.

[0357] Further, the commutation characteristic data includes a steady-state commutation angle, a steady-state triggering angle, a steady-state triggering phase interval, a first converter valve pre-touch angle and a second converter valve pre-touch angle, and the two commutation failure intervals include two continuous commutation failure intervals and two discontinuous commutation failure intervals. The interval determination module 303 includes: a first lower limit value submodule, which is used to use the commutation failure moment and the steady-state commutation angle to determine the interval lower limit value of the two continuous commutation failure intervals; a first upper limit value submodule, which is used to use the commutation failure moment and the steady-state triggering angle to determine the interval upper limit value of the two continuous commutation failure intervals; a second lower limit value submodule, which is used to use the commutation failure moment, the steady-state triggering angle and the first converter valve pre-touch angle to determine the interval lower limit value of the two discontinuous commutation failure intervals; and a second upper limit value submodule, which is used to use the commutation failure moment, the steady-state triggering phase interval, the steady-state triggering angle and the second converter valve pre-touch angle to determine the interval upper limit value of the two discontinuous commutation failure intervals.

[0358] Furthermore, the preset two commutation failure criteria include two continuous commutation failure criteria and two discontinuous commutation failure criteria. The two commutation determination module 304 includes: a two continuous commutation result submodule, which is used to determine the two continuous commutation results based on the two continuous commutation failure interval, the valve-side current waveform and the two continuous commutation failure criteria; and a two discontinuous commutation result submodule, which is used to determine the two discontinuous commutation results based on the two continuous commutation failure interval, the two discontinuous commutation failure interval, the valve-side current waveform and the two discontinuous commutation failure criteria.

[0359] Furthermore, the two-continuous commutation result submodule includes: a first continuous processing unit, which is used to determine whether the operating time of the target system is within the interval of two continuous commutation failures when a commutation failure is detected; a second continuous processing unit, which is used to determine whether the fourth commutation failure feature exists when the operating time of the target system is within the interval of two continuous commutation failures; a third continuous processing unit, which is used to determine whether the first-phase valve-side current waveform has an increasing trend; a fourth continuous processing unit, which is used to determine whether the first-phase valve-side current waveform has a maximum value when the first-phase valve-side current waveform has an increasing trend; a fifth continuous processing unit, which is used to determine whether the increasing trend of the first-phase valve-side current waveform has a decaying trend after reaching the maximum value when the first-phase valve-side current waveform has a maximum value; a sixth continuous processing unit, which is used to determine whether the fifth commutation failure feature exists when the increasing trend of the first-phase valve-side current waveform has a decaying trend after reaching the maximum value; a seventh continuous processing unit, which is used to determine whether the decaying trend is greater than a preset third current threshold; an eighth continuous processing unit, which is used to determine whether the decaying trend is greater than a preset third current threshold when the decaying trend is greater than a preset third current threshold; a ninth continuous processing unit for obtaining a first-phase valve-side current waveform of a first-phase valve-side current in a first-conversion phase valve-side current under a transformation coordinate; a tenth continuous processing unit for performing a sum operation using the first-phase valve-side current and the first-conversion phase valve-side current to generate a first sum; an eleventh continuous processing unit for determining whether the first sum is less than a preset first sum threshold; a twelfth continuous processing unit for determining the presence of a seventh commutation failure feature when the first sum is less than the preset first sum threshold; a first continuous determination unit for determining that the target system has not had two consecutive commutation failures and determining the presence of an eighth commutation failure feature when the valve-side current waveform does not simultaneously have the fourth commutation failure feature, the fifth commutation failure feature, the sixth commutation failure feature and the seventh commutation failure feature; a second continuous determination unit for determining that the target system has had two consecutive commutation failures when the valve-side current waveform simultaneously has the fourth commutation failure feature, the fifth commutation failure feature, the sixth commutation failure feature and the seventh commutation failure feature.

[0360] Furthermore, the two discontinuous commutation result submodule includes: a first discontinuous processing unit, which is used to determine whether the operating time of the target system is within the interval of two discontinuous commutation failures when a commutation failure is detected; a second discontinuous processing unit, which is used to determine the presence of the ninth commutation failure feature when the operating time of the target system is within the interval of two discontinuous commutation failures; a third discontinuous processing unit, which is used to determine whether the first-phase valve-side current waveform has an attenuation trend; a fourth discontinuous processing unit, which is used to determine whether there is an increasing trend after the attenuation trend of the first-phase valve-side current waveform reaches a minimum value when the first-phase valve-side current waveform has an attenuation trend; a fifth discontinuous processing unit, which is used to determine the presence of the tenth commutation failure feature when the attenuation trend of the first-phase valve-side current waveform reaches a minimum value and there is an increasing trend; a sixth discontinuous processing unit, which is used to determine whether the increasing trend is greater than a preset fourth current threshold; a seventh discontinuous processing unit, which is used to determine the presence of a tenth commutation failure feature when the increasing trend is greater than the preset fourth current threshold. in the eleventh commutation failure feature; the eighth discontinuous processing unit is used to perform a sum operation using the first-phase valve-side current of the first-phase valve-side current waveform and the second-phase valve-side current of the second-phase valve-side current waveform to generate a second sum; the ninth discontinuous processing unit is used to determine whether the second sum is less than a preset second sum threshold; the tenth discontinuous processing unit is used to determine that there is a twelfth commutation failure feature when the second sum is less than the preset second sum threshold; the third continuous determination unit is used to determine that the target system has not had two discontinuous commutation failures when the valve-side current waveform does not simultaneously have the ninth commutation failure feature, the tenth commutation failure feature, the eleventh commutation failure feature and the twelfth commutation failure feature, or the eighth commutation failure feature exists; the fourth continuous determination unit is used to determine that the target system has had two discontinuous commutation failures when the valve-side current waveform simultaneously has the ninth commutation failure feature, the tenth commutation failure feature, the eleventh commutation failure feature and the twelfth commutation failure feature, and the eighth commutation failure feature does not exist.

[0361] In the present invention, in response to a commutation detection request for a target system, a valve-side current waveform and commutation characteristic data of the target system are obtained; a commutation result is determined based on the valve-side current waveform and a preset commutation failure criterion; when a commutation result is a commutation failure, a two-commutation failure interval is determined based on the commutation failure moment of the one-commutation failure and the commutation characteristic data; two-commutation results are determined based on the two-commutation failure interval, the valve-side current waveform and the preset two-commutation failure criterion; the present invention first analyzes the valve-side current waveform of the target system through a one-commutation failure criterion obtained by pre-analysis to accurately obtain a commutation result, and then determines the two-commutation failure interval according to the commutation failure moment of the one-commutation failure, and finally obtains the two-commutation results in combination with the two-commutation failure criterion obtained by pre-analysis. The present invention can accurately identify the results of different types of commutation in a high-voltage direct current transmission system, accurately determine whether different commutation failure situations occur, and improve the operating stability of the high-voltage direct current transmission system.

[0362] See also Fig. 20 , Fig. 20 This is a structural block diagram of a computer device provided in Embodiment 4 of the present invention.

[0363] An electronic device according to an embodiment of the present invention includes: a memory 401 and a processor 402, wherein the memory 402 stores a computer program; when the computer program is executed by the processor 402, the processor 402 executes a method for detecting high-voltage direct current commutation failures adapted to multiple types as described in any of the above embodiments.

[0364] The memory 401 may be an electronic memory such as a flash memory, an EEPROM (electrically erasable programmable read-only memory), an EPROM, a hard disk or a ROM. The memory 401 has a storage space 403 for a program code 413 for executing any method step in the above method. For example, the storage space 403 for the program code may include individual program codes 413 for implementing the various steps in the above method, respectively. These program codes may be read from or written to one or more computer program products. These computer program products include program code carriers such as hard disks, compact disks (CDs), memory cards or floppy disks. The program code may be compressed, for example, in an appropriate form. When these codes are run by a computing and processing device, the computing and processing device performs the various steps in the method described above. These program codes may be read from or written to one or more computer program products. These computer program products include program code carriers such as hard disks, compact disks (CDs), memory cards or floppy disks. The program code may be compressed, for example, in an appropriate form. When these codes are executed by a computing and processing device, the computing and processing device is caused to execute the various steps of the above-described method for detecting high-voltage direct current commutation failures that are adaptable to multiple types.

[0365] Embodiment 5 of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the method for detecting high-voltage direct current commutation failures adaptable to multiple types as described in any of the above embodiments is implemented.

[0366] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0367] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0368] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0369] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0370] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0371] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for detecting high voltage direct current commutation failures that is adaptable to multiple types, characterized in that: include: In response to a commutation detection request for a target system, a valve-side current waveform and commutation characteristic data of the target system are acquired; Determining a primary commutation result based on the valve-side current waveform and a preset primary commutation failure criterion; When the commutation result is a commutation failure, two commutation failure intervals are determined based on the commutation failure moment of the commutation failure and the commutation characteristic data; Based on the two commutation failure intervals, the valve-side current waveform and the preset two commutation failure criteria, two commutation results are determined.

2. The method for detecting high voltage direct current commutation failures adapted to multiple types according to claim 1, characterized in that: The preset primary commutation failure criterion includes an atypical commutation failure criterion and a typical commutation failure criterion, and determining a primary commutation result based on the valve-side current waveform and the preset primary commutation failure criterion includes: When the valve-side current waveform satisfies the atypical commutation failure criterion, it is determined that an atypical commutation failure occurs in the target system; When the valve-side current waveform meets the typical commutation failure criterion, it is determined that a typical commutation failure occurs in the target system; When the atypical commutation failure or the typical commutation failure does not exist, determining a commutation result as no commutation failure occurs; When the atypical commutation failure or the typical commutation failure occurs, a commutation result is determined to be a commutation failure.

3. The method for detecting high voltage direct current commutation failures adapted to multiple types according to claim 2, characterized in that: When the valve-side current waveform satisfies the atypical commutation failure criterion, determining that the target system has an atypical commutation failure includes: Acquire a first-phase valve-side current waveform and a second-phase valve-side current waveform when the valve-side current is a negative value in the valve-side current waveform; Determining whether the first-phase valve-side current waveform has an increasing trend; When the first-phase valve-side current waveform has an increasing trend, determining whether the increasing trend is greater than a preset first current threshold; When the increasing trend is greater than the preset first current threshold, it is determined that a first commutation failure feature exists; determining whether the second-phase valve-side current waveform has a minimum value; When the second phase valve side current waveform has a minimum value, it is determined that the second commutation failure feature exists; determining whether, after the second-phase valve-side current waveform reaches the minimum value, the increasing trend of the second-phase valve-side current waveform is greater than a preset second current threshold; When the increasing trend of the second-phase valve-side current waveform is greater than a preset second current threshold, it is determined that a third commutation failure feature exists; When the valve-side current waveform simultaneously has the first commutation failure feature, the second commutation failure feature, and the third commutation failure feature, it is determined that an atypical commutation failure occurs in the target system.

4. The method for detecting high voltage direct current commutation failures adapted to multiple types according to claim 3 is characterized in that: The commutation characteristic data includes a steady-state commutation angle, a steady-state triggering angle, a steady-state triggering phase interval, a first converter valve pre-touch angle, and a second converter valve pre-touch angle. The two commutation failure intervals include two continuous commutation failure intervals and two discontinuous commutation failure intervals. The two commutation failure intervals are determined based on the commutation failure moment of a commutation failure and the commutation characteristic data, including: Determine the lower limit of the interval of the two consecutive commutation failure intervals by using the commutation failure moment and the steady-state commutation angle; Determine the upper limit value of the interval of the two consecutive commutation failure intervals by using the commutation failure moment and the steady-state trigger angle; Determine the lower limit value of the interval of the two discontinuous commutation failure intervals by using the commutation failure moment, the steady-state trigger angle and the first converter valve pre-touch angle; The upper limit value of the interval of the two discontinuous commutation failure intervals is determined by using the commutation failure moment, the steady-state trigger phase interval, the steady-state trigger angle and the second converter valve pre-touch angle.

5. The method for detecting high voltage direct current commutation failures adapted to multiple types according to claim 4, characterized in that: The preset two commutation failure criteria include two continuous commutation failure criteria and two discontinuous commutation failure criteria. The two commutation results are determined based on the two commutation failure intervals, the valve-side current waveform and the preset two commutation failure criteria, including: Determining two consecutive commutation results based on the two consecutive commutation failure intervals, the valve-side current waveform and the two consecutive commutation failure criteria; Based on the two continuous commutation failure intervals, the two discontinuous commutation failure intervals, the valve-side current waveform and the two discontinuous commutation failure criteria, two discontinuous commutation results are determined.

6. The method for detecting high voltage direct current commutation failures adapted to multiple types according to claim 5, characterized in that: The determining of two consecutive commutation results based on the two consecutive commutation failure intervals, the valve-side current waveform and the two consecutive commutation failure criteria includes: When the one commutation failure is detected, determining whether the operation time of the target system is within the interval of the two consecutive commutation failures; When the operation time of the target system is within the interval of two consecutive commutation failures, it is determined that a fourth commutation failure feature exists; Determining whether the first-phase valve-side current waveform has an increasing trend; When the first-phase valve-side current waveform has an increasing trend, determining whether the first-phase valve-side current waveform has a maximum value; When the first-phase valve-side current waveform has a maximum value, determining whether the first-phase valve-side current waveform has a decay trend after the increasing trend reaches the maximum value; When the increasing trend of the first phase valve side current waveform reaches a maximum value and then has a decaying trend, it is determined that there is a fifth commutation failure feature; Determining whether the attenuation trend is greater than a preset third current threshold; When the attenuation trend is greater than the preset third current threshold, it is determined that the sixth commutation failure feature exists; Acquire a first-phase valve-side current of the first-phase valve-side current waveform in which the first-phase valve-side current is in a first-transformed phase valve-side current under a transformed coordinate; Performing a sum operation on the first phase valve-side current and the first conversion phase valve-side current to generate a first sum value; Determine whether the first sum value is less than a preset first sum value threshold; When the first sum value is less than the preset first sum value threshold, it is determined that the seventh commutation failure feature exists; When the valve-side current waveform does not simultaneously have the fourth commutation failure feature, the fifth commutation failure feature, the sixth commutation failure feature, and the seventh commutation failure feature, it is determined that the target system does not have two consecutive commutation failures, and it is determined that the eighth commutation failure feature exists; When the valve-side current waveform simultaneously has the fourth commutation failure feature, the fifth commutation failure feature, the sixth commutation failure feature, and the seventh commutation failure feature, it is determined that two consecutive commutation failures occur in the target system.

7. The method for detecting high voltage direct current commutation failures adapted to multiple types according to claim 6, characterized in that: The determining of two discontinuous commutation results based on the two continuous commutation failure intervals, the two discontinuous commutation failure intervals, the valve-side current waveform and the two discontinuous commutation failure criteria includes: When the one commutation failure is detected, determining whether the operation time of the target system is within the interval of the two discontinuous commutation failures; When the operation time of the target system is within the interval of the two discontinuous commutation failures, it is determined that the ninth commutation failure feature exists; Determining whether the first-phase valve-side current waveform has a decay trend; When the first-phase valve-side current waveform has a decaying trend, determining whether there is an increasing trend after the decaying trend of the first-phase valve-side current waveform reaches a minimum value; When the attenuation trend of the first phase valve side current waveform reaches a minimum value and then has an increasing trend, it is determined that there is a tenth commutation failure feature; Determining whether the increasing trend is greater than a preset fourth current threshold; When the increasing trend is greater than the preset fourth current threshold, it is determined that the eleventh commutation failure feature exists; Performing a sum operation on a first-phase valve-side current of the first-phase valve-side current waveform and a second-phase valve-side current of the second-phase valve-side current waveform to generate a second sum; Determine whether the second sum is less than a preset second sum threshold; When the second sum value is less than the preset second sum value threshold, it is determined that a twelfth commutation failure feature exists; When the valve-side current waveform does not simultaneously have the ninth commutation failure feature, the tenth commutation failure feature, the eleventh commutation failure feature and the twelfth commutation failure feature, or has the eighth commutation failure feature, it is determined that the target system does not have two discontinuous commutation failures; When the valve-side current waveform simultaneously has the ninth commutation failure feature, the tenth commutation failure feature, the eleventh commutation failure feature and the twelfth commutation failure feature, and does not have the eighth commutation failure feature, it is determined that the target system has two discontinuous commutation failures.

8. A high voltage direct current commutation failure detection system adapted to multiple types, characterized in that: include: A response module, used to respond to a commutation detection request for a target system, and obtain a valve-side current waveform and commutation characteristic data of the target system; A primary commutation determination module, used to determine a primary commutation result based on the valve-side current waveform and a preset primary commutation failure criterion; An interval determination module, for determining two commutation failure intervals based on the commutation failure moment of the one commutation failure and the commutation characteristic data when the one commutation result is a commutation failure; The two-phase commutation determination module is used to determine the two-phase commutation results based on the two-phase commutation failure intervals, the valve-side current waveform and the preset two-phase commutation failure criteria.

9. An electronic device, characterized in that: It comprises a memory and a processor, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the processor executes the steps of the method for detecting high-voltage direct current commutation failures adapted to multiple types as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the method for detecting high-voltage direct current commutation failures adaptable to multiple types of applications as described in any one of claims 1 to 7 is implemented.

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