Alternating current and direct current fault protection method of hybrid commutation converter valve and related equipment thereof

Abstract

The invention discloses an alternating-current and direct-current fault protection method of a hybrid commutation converter valve and related equipment thereof, and relates to the technical field of high-voltage direct-current power transmission. The method comprises the steps of obtaining an AC voltage of an AC side, a target trigger angle of a hybrid commutation converter valve and a DC current of a DC side, and determining an extinction angle margin risk factor and a volt-second area margin risk factor according to at least one of the above, the extinction angle margin risk factor being used for representing a commutation success margin, and the volt-second area margin risk factor being used for representing a target trigger angle of the hybrid commutation converter valve; the volt-second area margin risk factor is used for representing the commutation driving capability; determining a commutation failure risk index based on the extinction angle margin risk factor, the volt-second area margin risk factor and the prediction confidence factor; and when the commutation failure risk index is abnormal, controlling and triggering the hybrid commutation converter valve to enter a corresponding commutation enhancement mode or an active turn-off mode based on the commutation failure risk index. According to the embodiment of the invention, active intervention can be carried out before the commutation failure is caused by the AC / DC fault, so that the commutation failure can be fully resisted.

Description

Technical Field

[0001] The present application belongs to the field of high-voltage direct current (HVDC) transmission technology, and in particular relates to an AC / DC fault protection method for a hybrid commutation converter valve and related equipment. Background Art

[0002] With the rapid growth of high-proportion renewable energy grid integration and cross-regional power transmission demand, the topology of AC / DC hybrid power grids is becoming increasingly complex, and their operational vulnerability has significantly increased. Traditional DC transmission technology based on thyristor converters, LCC-HVDC (Line Commutated Converter High Voltage Direct Current), suffers from shortcomings such as high probability of commutation failure, large reactive power demand, and slow dynamic response due to the inherent characteristics of its semi-controlled devices. When a local AC fault causes a deep voltage drop in the grid, the transient distortion of the commutation voltage and insufficient reactive power support capacity can easily trigger a chain reaction of commutation failures, leading to DC system lockout or even transient instability. In extreme cases, it can even induce large-scale power outages, with profound impacts on the society and economy. Developing new commutation technologies that can effectively improve the fault ride-through capability and robustness of DC systems has become a key issue that needs to be urgently addressed in the current power sector.

[0003] As a fully controlled power electronic device, the integrated gate-commutated thyristor (IGCT), with its nanosecond-level rapid shutdown capability and bidirectional blocking characteristics, provides a solid physical foundation for the construction of an active defensive hybrid commutation converter valve (HCC). The IGCT's rapid current interruption capability can effectively suppress the abnormal growth of fault current in the early stages of an AC fault, fundamentally reducing the risk of commutation failure. Compared to LCC-HVDC systems, the operating characteristics of HCC-HVDC (Hybrid Commutation Converter High Voltage Direct Current) systems have undergone profound changes: in the active shutdown forced commutation mode to respond to commutation failures, the IGCT's shutdown causes the HCC to exhibit transient intermittent characteristics; recovery-enhanced natural commutation allows the HCC to actively alter the device's recovery process.

[0004] However, the high-frequency switching dynamics of IGCT devices and the strong coupling characteristics of AC / DC systems present new challenges for the design of control and protection strategies. Currently, HCC lacks the ability to proactively intervene in complex AC / DC fault scenarios, preventing commutation failures caused by these faults. Consequently, HCC cannot adequately mitigate the risk of commutation failures, posing a threat to the safe and stable operation of the system. Summary of the Invention

[0005] The embodiments of the present application provide an AC / DC fault protection method for a hybrid commutation valve and related equipment, which can actively intervene before an AC / DC fault causes a commutation failure, thereby fully preventing the commutation failure and improving the operational safety of the power transmission system.

[0006] In a first aspect, an embodiment of the present application provides an AC / DC fault protection method for a hybrid commutation valve, wherein the hybrid commutation valve is used to connect an AC side and a DC side. The AC / DC fault protection method for the hybrid commutation valve includes:

[0007] Obtaining the AC voltage on the AC side, the target trigger angle of the hybrid commutation valve, and the DC current on the DC side;

[0008] Determining an arc extinction angle margin risk factor and a volt-second area margin risk factor based on at least one of the AC voltage, the target trigger angle, and the DC current, wherein the arc extinction angle margin risk factor is used to characterize the commutation success margin, and the volt-second area margin risk factor is used to characterize the commutation drive capability;

[0009] Determine the commutation failure risk index based on the arc extinction angle margin risk factor, the volt-second area margin risk factor, and the prediction confidence factor;

[0010] In the case of an abnormal commutation failure risk index, the hybrid commutation valve is controlled and triggered to enter the corresponding commutation enhancement mode or active shutdown mode based on the commutation failure risk index.

[0011] In some possible implementations, before obtaining the AC voltage on the AC side, the target trigger angle of the hybrid commutation valve, and the DC current on the DC side, the AC / DC fault protection method for the hybrid commutation valve further includes:

[0012] Acquire a target monitoring signal on the DC side and output a DC state signal according to the target monitoring signal, wherein the target monitoring signal includes at least one of the DC voltage, the DC voltage change rate, and the DC current change rate on the DC side;

[0013] Obtaining the AC voltage on the AC side, the target trigger angle of the hybrid commutation valve, and the DC current on the DC side, including:

[0014] When the DC state signal is a normal signal, the AC voltage, the target trigger angle, and the DC current are obtained.

[0015] In some possible implementations, obtaining a target monitoring signal on the DC side and outputting a DC state signal according to the target monitoring signal includes:

[0016] When the target monitoring signal meets the DC fault criterion, the output DC state signal is a DC fault signal;

[0017] When the target monitoring signal does not meet the DC fault criterion, the output DC state signal is a normal signal;

[0018] The DC fault criteria include: the DC voltage is less than the DC voltage fault threshold, the DC voltage change rate is less than the fault voltage change rate threshold, or the DC current change rate is less than the fault current change rate threshold.

[0019] In some possible implementations, determining the arc extinction angle margin risk factor and the volt-second area margin risk factor based on at least one of the AC voltage, the target firing angle, and the DC current includes:

[0020] Determining a predicted arc extinction angle based on a target firing angle, a DC current, and a commutation reactance of a hybrid commutation valve, and determining an arc extinction angle margin risk factor based on the predicted arc extinction angle;

[0021] A net available volt-second area margin is determined based on the AC voltage, the target firing angle, the DC current, and the commutation reactance, and a volt-second area margin risk factor is determined based on the net available volt-second area margin.

[0022] In some possible implementations, determining the arc extinction angle margin risk factor based on the predicted arc extinction angle includes:

[0023] Based on the predicted arc extinction angle, the arc extinction angle margin risk factor is determined by a first calculation formula;

[0024] The first calculation formula includes:

[0025]

[0026] Among them, R γ is the arc extinction angle margin risk factor, γ th,CE is the predicted arc extinction angle threshold for triggering the commutation enhancement mode; γ pred To predict the arc extinction angle, γ crit is the critical predicted arc extinction angle for triggering the active shutdown mode, γ min_ctrl is the minimum arc extinction angle.

[0027] In some possible implementations, determining the predicted arc extinction angle based on the target firing angle, the DC current, and the commutation reactance of the hybrid commutation valve includes:

[0028] Based on the target trigger angle, DC current and commutation reactance, the predicted arc extinction angle is determined by a second calculation formula;

[0029] The second calculation formula includes:

[0030] γ pred =180°-α-2L c I dc

[0031] Among them, γ pred is the predicted arc extinction angle, α is the target trigger angle, I dc is the DC current, L c is the commutation reactance.

[0032] In some possible implementations, determining a volt-second area margin risk factor based on the net available volt-second area margin includes:

[0033] Based on the net available volt-second area margin, determine the volt-second area margin risk factor using a third calculation formula;

[0034] The third calculation formula includes:

[0035]

[0036] Among them, R VSA is the volt-second area margin risk factor, A CE A is the volt-second area margin threshold required to trigger the commutation enhancement mode. γ The critical volt-second area margin required to trigger the active shutdown mode, A net is the net available volt-second area margin.

[0037] In some possible implementations, determining the net available volt-second area margin based on the AC voltage, the target firing angle, the DC current, and the commutation reactance includes:

[0038] Based on the AC voltage, target firing angle, DC current, and commutation reactance, the net available volt-second area margin is determined using the fourth calculation formula;

[0039] The fourth calculation formula includes:

[0040]

[0041] Among them, A net is the net available volt-second area margin, I dc is the DC current, L c is the commutation reactance, α is the target trigger angle, U L (t) is the AC voltage, and ω is the angular frequency of the hybrid commutation valve.

[0042] In some possible implementations, determining a commutation failure risk index based on the arc extinction angle margin risk factor, the volt-second area margin risk factor, and the prediction confidence factor includes:

[0043] A commutation failure risk index is determined based on a product of an arc extinction angle margin risk factor and a first weight coefficient, a product of a volt-second area margin risk factor and a second weight coefficient, and a prediction confidence factor.

[0044] In some possible implementations, determining a commutation failure risk index based on a product of an arc extinction angle margin risk factor and a first weight coefficient, a product of a volt-second area margin risk factor and a second weight coefficient, and a prediction confidence factor includes:

[0045] Determine a commutation failure risk index using a fifth calculation formula based on the product of the arc extinction angle margin risk factor and the first weight coefficient, the product of the volt-second area margin risk factor and the second weight coefficient, and the prediction confidence factor;

[0046] The fifth calculation formula includes:

[0047]

[0048] Among them, CFRI is the commutation failure risk index, R γ is the arc extinction angle margin risk factor, R VSA is the volt-second area margin risk factor, W γ is the first weight coefficient, W VSA is the second weight coefficient, C pred is the prediction confidence factor.

[0049] In some possible implementations, when the commutation failure risk index is abnormal, controlling and triggering the hybrid commutation valve to enter the corresponding commutation enhancement mode or active shutdown mode based on the commutation failure risk index includes:

[0050] When the commutation failure risk index is greater than or equal to a first preset threshold, controlling and triggering the hybrid commutation valve to enter an active shutdown mode;

[0051] When the commutation failure risk index is less than a first preset threshold and greater than or equal to a second preset threshold, the hybrid commutation valve is controlled to enter a commutation enhancement mode, wherein the first preset threshold is greater than the second preset threshold.

[0052] Based on the same inventive concept, in a second aspect, an embodiment of the present application provides an AC / DC fault protection device for a hybrid commutation valve, wherein the hybrid commutation valve is used to connect an AC side and a DC side; the AC / DC fault protection device for the hybrid commutation valve includes:

[0053] A first acquisition module is used to obtain the AC voltage on the AC side, the target trigger angle of the hybrid commutation valve, and the DC current on the DC side;

[0054] a first determining module, configured to determine an arc extinction angle margin risk factor and a volt-second area margin risk factor based on at least one of the AC voltage, the target trigger angle, and the DC current, wherein the arc extinction angle margin risk factor is used to characterize the commutation success margin, and the volt-second area margin risk factor is used to characterize the commutation drive capability;

[0055] A second determination module is configured to determine a commutation failure risk index based on an arc extinction angle margin risk factor, a volt-second area margin risk factor, and a prediction confidence factor;

[0056] The first trigger module is used to control and trigger the hybrid commutation valve to enter the corresponding commutation enhancement mode or active shutdown mode based on the commutation failure risk index when the commutation failure risk index is abnormal.

[0057] In a third aspect, an embodiment of the present application provides an AC / DC fault protection device for a hybrid commutation valve, the AC / DC fault protection device for a hybrid commutation valve comprising:

[0058] a processor and a memory storing computer program instructions;

[0059] When the processor executes the computer program instructions, the AC / DC fault protection method for the hybrid commutation valve provided in any one of the above embodiments of the present application is implemented.

[0060] In a fourth aspect, an embodiment of the present application provides a computer storage medium, on which computer program instructions are stored. When the computer program instructions are executed by a processor, an AC / DC fault protection method for a hybrid phase-changing valve is implemented as provided in any one of the above-mentioned embodiments of the present application.

[0061] In a fifth aspect, an embodiment of the present application provides a computer program product. When the instructions in the computer program product are executed by a processor of an electronic device, the electronic device executes the AC / DC fault protection method for a hybrid phase-changing valve provided in any one of the above-mentioned embodiments of the present application.

[0062] Embodiments of the present application provide a hybrid commutation valve AC / DC fault protection method and related equipment. The method obtains the AC voltage on the AC side, the target trigger angle of the hybrid commutation valve, and the DC current on the DC side; determines an arc extinction angle margin risk factor and a volt-second area margin risk factor based on at least one of the AC voltage, target trigger angle, and DC current. Subsequently, a commutation failure risk index is determined based on the arc extinction angle margin risk factor, the volt-second area margin risk factor, and a prediction confidence factor. If the commutation failure risk index is abnormal, the method controls the hybrid commutation valve to enter a corresponding commutation enhancement mode or active shutdown mode based on the commutation failure risk index.

[0063] From the above description, it can be seen that the AC / DC fault protection method and related equipment of a hybrid commutation valve in an embodiment of the present application determines the arc extinction angle margin risk factor and the volt-second area margin risk factor based on at least one of the AC voltage, the target trigger angle, and the DC current, and then accurately quantifies the commutation failure risk by combining the arc extinction angle margin risk factor, the volt-second area margin risk factor, and the prediction confidence factor, thereby finally calculating the commutation risk failure index, thereby achieving a dynamic and quantitative characterization of the possibility of commutation failure. Based on the commutation risk failure index, the corresponding commutation enhancement mode or active shutdown mode can be accurately, reliably, and timely triggered in the event of an abnormality, thereby achieving effective active intervention before the AC / DC fault causes commutation failure, fully resisting the risk of commutation failure, and improving the operational safety and stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0065] Figure 1 1 is a flow chart of an AC / DC fault protection method for a hybrid commutation valve provided in one embodiment of the present application;

[0066] Figure 2 This is a scenario flow diagram of an AC / DC fault protection method for a hybrid commutation valve provided in one embodiment of the present application;

[0067] Figure 3 This is a schematic diagram of transient responses of relevant parameters under a deep fault provided by an embodiment of the present application;

[0068] Figure 4 1 is a schematic structural diagram of an AC / DC fault protection device for a hybrid commutation valve provided in one embodiment of the present application;

[0069] Figure 5It is a structural diagram of an AC / DC fault protection device for a hybrid phase-commutated converter valve provided in one embodiment of the present application. DETAILED DESCRIPTION

[0070] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is merely to provide a better understanding of the present application by illustrating the examples of the present application.

[0071] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, the elements defined by the phrase "comprising..." do not exclude the presence of other identical elements in the process, method, article, or device comprising the elements.

[0072] It should be noted that in the embodiments of the present application, certain software, components, models and other existing solutions in the industry may be mentioned. They should be regarded as exemplary. Their purpose is only to illustrate the feasibility of implementing the technical solution of the present application, but it does not mean that the applicant has or will necessarily use the solution.

[0073] As mentioned in the background technology section, in complex AC / DC fault scenarios, HCC currently lacks the ability to proactively intervene in the risk of commutation failure caused by system AC / DC faults, thus failing to adequately protect against the risk of commutation failure, posing a threat to the safe and stable operation of the system. The high-frequency switching dynamics of IGCT devices and the strong coupling characteristics of AC / DC systems pose new challenges to the design of control and protection strategies.

[0074] Specifically, traditional DC protection and AC relay protection are typically designed independently, lacking dynamic interaction and coordination mechanisms. Conventional DC fault protection strategies primarily implement protection actions based on a single criterion, the bridge arm current. This approach has certain limitations. On the one hand, the sensitivity of high-resistance faults and weak grids is severely reduced, and the fault signals are not obvious. The sensitivity and reliability of traditional protection methods are significantly reduced, and the risk of missed detection increases sharply when shallow short-circuit faults occur on the AC side voltage. On the other hand, its excessive sensitivity increases the probability of false triggering of protection during normal commutation, causing unnecessary lockout. In AC / DC hybrid power grids, the strong coupling characteristics of AC and DC further amplify the defects. The voltage drop caused by AC-side faults propagates to the DC side through the HCC converter, significantly increasing the probability of triggering commutation failure compared to pure AC systems. Traditional protection cannot effectively distinguish the coupling paths of AC and DC faults, making it difficult to meet the stringent protection selectivity and reliability requirements of new power systems.

[0075] At the same time, the dynamic impact of AC / DC cross-coupling creates coordination blind spots. Traditional AC protection and DC control protection systems operate independently, lacking real-time interaction mechanisms and unable to effectively address the mutual impact of AC / DC faults. In scenarios where AC / DC faults interact, isolated designs make it difficult to coordinate protection actions. AC-side faults can rapidly increase the risk of DC-side commutation failure, but DC protection cannot obtain timely AC-side information to adjust its strategy, further exacerbating the consequences of the fault. DC-side problems can also spread to the AC side, impacting overall protection reliability. Furthermore, ignoring the impact of AC / DC fault coupling can lead to misjudgment or failure of AC protection devices, complicating system recovery. During system recovery, the combined effects of inrush current and low short-circuit capacity significantly reduce the fault type identification accuracy of existing reclosing strategies. This not only delays fault isolation but also increases the risk of secondary shocks, posing a threat to grid stability.

[0076] Based on this, existing technologies have obvious deficiencies in the quantitative prediction of dynamic commutation failure risks, the precise triggering of HCC active intervention capabilities, and the collaborative decision-making of AC / DC protection systems. Therefore, they cannot effectively resist the risk of dynamic commutation failure under complex AC / DC faults.

[0077] In view of the above, in order to solve the problems of the prior art, the embodiments of the present application provide an AC / DC fault protection method for a hybrid phase-commutated converter valve and related equipment. It should be noted that the embodiments provided in this application are not intended to limit the scope of the disclosure of this application.

[0078] The following first introduces the AC / DC fault protection method for the hybrid commutation valve provided in the embodiment of the present application.

[0079] Figure 1The figure shows a flow chart of an AC / DC fault protection method for a hybrid commutation converter valve provided by an embodiment of the present application. The AC / DC fault protection method for a hybrid commutation converter valve is applied to a control device in an AC / DC power transmission system, such as a control and protection system (CPS) or a valve control system (VCS), which can be used to monitor, control and protect the operating status of the converter valve. Figure 1 As shown, a hybrid commutation valve is used to connect the AC side and the DC side; the AC / DC fault protection method of the hybrid commutation valve includes the following steps:

[0080] S110, obtaining an AC voltage on the AC side, a target trigger angle of a hybrid commutation valve, and a DC current on the DC side;

[0081] S120, determining an arc extinction angle margin risk factor and a volt-second area margin risk factor based on at least one of the AC voltage, the target trigger angle, and the DC current, wherein the arc extinction angle margin risk factor is used to characterize a commutation success margin, and the volt-second area margin risk factor is used to characterize a commutation drive capability;

[0082] S130, determining a commutation failure risk index based on the arc extinction angle margin risk factor, the volt-second area margin risk factor, and the prediction confidence factor;

[0083] S140 , when the commutation failure risk index is abnormal, based on the commutation failure risk index, controlling and triggering the hybrid commutation valve to enter the corresponding commutation enhancement mode or active shutdown mode.

[0084] From the above description, it can be seen that the AC / DC fault protection method for a hybrid commutation valve in an embodiment of the present application determines the arc extinction angle margin risk factor and the volt-second area margin risk factor based on at least one of the AC voltage, the target trigger angle, and the DC current, and then accurately quantifies the commutation failure risk by combining the arc extinction angle margin risk factor, the volt-second area margin risk factor, and the prediction confidence factor, thereby ultimately calculating the commutation risk failure index, thereby achieving a dynamic and quantitative characterization of the possibility of commutation failure. Based on the commutation risk failure index, the corresponding commutation enhancement mode or active shutdown mode can be accurately, reliably, and timely triggered in the event of an abnormality, thereby achieving effective active intervention before the AC / DC fault causes commutation failure, fully resisting the risk of commutation failure, and improving the operational safety and stability of the system.

[0085] The specific implementation of the above steps 110 to 140 is described in detail below.

[0086] In S110, during specific implementation, the hybrid commutation valve is used to connect the AC side and the DC side, and can operate in a tumor mode or an inverter mode through its internal thyristors and fully controlled devices (such as IGCT), thereby realizing conversion between AC and DC.

[0087] The AC voltage on the AC side may specifically be, for example, three instantaneous line voltages on the AC side of the hybrid commutation valve. The AC voltage may be collected and fed back by a measuring device such as a voltage transformer provided on the AC side.

[0088] The target trigger angle of the hybrid commutation valve may be, for example, the actual trigger angle of the hybrid commutation valve in its current working state, or the trigger angle that the control system is about to send to the hybrid commutation valve, which is not strictly limited here.

[0089] During normal operation of the AC / DC system, the target firing angle is typically a fixed value. In some cases, the target firing angle can be adjusted based on actual needs to adjust the conduction timing of the hybrid commutation valve, thereby regulating the DC voltage and current.

[0090] The DC voltage on the DC side can be obtained by collecting and feeding back the DC voltage through a current sensor or other measuring device provided on the DC transmission line.

[0091] It should be understood that the AC voltage on the AC side, the target trigger angle of the hybrid commutation valve and the DC current on the DC side may be obtained simultaneously or at different times, which is not limited here.

[0092] According to some embodiments of the present application, optionally, before obtaining the AC voltage on the AC side, the target trigger angle of the hybrid commutation valve, and the DC current on the DC side, the AC / DC fault protection method of the hybrid commutation valve further includes:

[0093] Acquire a target monitoring signal on the DC side and output a DC state signal according to the target monitoring signal, wherein the target monitoring signal includes at least one of the DC voltage, the DC voltage change rate, and the DC current change rate on the DC side;

[0094] Obtaining the AC voltage on the AC side, the target trigger angle of the hybrid commutation valve, and the DC current on the DC side, including:

[0095] When the DC state signal is a normal signal, the AC voltage, the target trigger angle, and the DC current are obtained.

[0096] In this embodiment, considering that faults on the DC side often directly affect the stability of the entire power transmission system, in order to more reasonably achieve accurate coordination of fault protection in AC and DC systems, key signals on the DC side are monitored first, thereby quickly realizing the status judgment of the DC side.

[0097] Specifically, the target monitoring signal includes at least one of the DC voltage, the rate of change of the DC voltage, and the rate of change of the DC current on the DC side. The target monitoring signal can be obtained by acquiring the DC voltage and DC current on the DC side and performing corresponding data processing on the DC voltage and DC current. It should be noted that in this embodiment, the DC current acquired in S110 can be directly acquired during this process to reduce repeated data acquisition.

[0098] Thus, after obtaining at least one of the DC voltage, the DC voltage change rate, and the DC current change rate of the DC side, whether the DC side status is normal is determined based on the parameter value. For example, each parameter value in the target monitoring signal is compared with a threshold value. If the comparison result indicates that the DC side is currently normal, the output DC status signal is a normal signal.

[0099] Once the DC side is confirmed to be normal, the AC voltage, target firing angle, and DC current are then acquired to predict the risk of commutation failure on the AC side. This prioritizes DC side fault detection, allowing for timely implementation of protective measures, rapid fault isolation, and prevention of escalation. This DC-first, AC-later protection strategy more effectively safeguards the safe operation of the entire AC / DC system and reduces the risk of commutation failure.

[0100] According to some embodiments of the present application, optionally, obtaining a target monitoring signal on the DC side and outputting a DC state signal according to the target monitoring signal includes:

[0101] When the target monitoring signal meets the DC fault criterion, the output DC state signal is a DC fault signal;

[0102] When the target monitoring signal does not meet the DC fault criterion, the output DC state signal is a normal signal;

[0103] The DC fault criteria include: the DC voltage is less than the DC voltage fault threshold, the DC voltage change rate is less than the fault voltage change rate threshold, or the DC current change rate is less than the fault current change rate threshold.

[0104] In specific implementation, as an example, the target monitoring signal includes: DC voltage V dc , DC voltage change rate dV dc / dt, DC current change rate dI dc / dt.

[0105] When judging the target monitoring signal, a logical "OR" combination is adopted by combining multiple DC fault judgment criteria. The specific DC fault judgment method is as follows (1):

[0106]

[0107] Among them, DC_Status is the DC status signal, which can support the output of normal signal or DC fault signal; DC_Fault is the DC fault signal, V dcmin It is the DC voltage fault threshold, and the specific value can be set to 70%-80% of the rated DC voltage. fault_negative Is the fault voltage change rate threshold, for HCC system can be selected as -1000V / ms. fault_positive is the fault current change rate threshold, which can be selected as 100A / ms for the HCC system.

[0108] It should be added that the above threshold values ​​are only used as examples and do not play a substantial role in limiting the specific DC fault determination in this application.

[0109] In this embodiment, the DC protection focuses on rapidly detecting and isolating DC-side faults. Based on the simple and reliable threshold criteria, it achieves a rapid response time of microseconds to milliseconds, effectively blocking the occurrence of DC faults and rapidly isolating the fault to prevent further escalation. Furthermore, in normal conditions without DC faults, subsequent defensive HCC control measures are triggered, effectively protecting the safe operation of the entire AC / DC system and reducing the risk of commutation failure.

[0110] It should be understood that in this embodiment, a locking operation will be performed when a DC fault is detected. The locking operation can be, for example: by sending a locking signal to the hybrid phase-commutating valve to stop the conduction of each switching device, thereby cutting off the fault current loop; it can also be by controlling the disconnection of the DC side disconnector, circuit breaker, etc., so as to facilitate rapid fault isolation and protect system safety. No strict restrictions are made here.

[0111] In S120, during specific implementation, in this step, margin assessment of the arc extinction angle margin risk factor and the volt-second area margin risk factor is performed based on at least one of the AC voltage, the target trigger angle, and the DC current.

[0112] The aforementioned arc extinction angle margin risk factor characterizes the commutation success margin. The volt-second area margin risk factor characterizes commutation drive capability and is adaptable to AC voltage distortion. These two risk factors can be used to dynamically quantify the likelihood of commutation failure.

[0113] According to some embodiments of the present application, optionally, determining an arc extinction angle margin risk factor and a volt-second area margin risk factor based on at least one of an AC voltage, a target trigger angle, and a DC current includes:

[0114] Determining a predicted arc extinction angle based on a target firing angle, a DC current, and a commutation reactance of a hybrid commutation valve, and determining an arc extinction angle margin risk factor based on the predicted arc extinction angle;

[0115] A net available volt-second area margin is determined based on the AC voltage, the target firing angle, the DC current, and the commutation reactance, and a volt-second area margin risk factor is determined based on the net available volt-second area margin.

[0116] In this embodiment, a predicted extinction angle is determined based on the target firing angle, the DC current, and the commutation reactance of the hybrid-commutated converter valve. A further extinction angle margin risk factor is determined based on the predicted extinction angle. This extinction angle margin risk factor can be used to measure the proximity of the predicted extinction angle to the critical extinction angle and the threshold angle for triggering the enhanced mode.

[0117] Furthermore, a net available volt-second area margin is determined based on the AC voltage, target firing angle, DC current, and commutation reactance, and a volt-second area margin risk factor is determined based on the net available volt-second area margin. The volt-second area margin risk factor can quantify the risk of commutation failure caused by insufficient net available volt-second area margin.

[0118] The commutation reactance of the above-mentioned hybrid commutation valve can be calculated in advance based on the short-circuit voltage, rated current and other parameters of the hybrid commutation converter. The commutation reactance can be stored in the control system in advance for use in predicting the arc extinction angle and calculating the net available volt-second area margin.

[0119] The calculation methods of the above-mentioned predicted arc extinction angle, arc extinction angle margin risk factor, net available volt-second area margin and volt-second area margin risk factor are introduced one by one below.

[0120] According to some embodiments of the present application, optionally, determining the arc extinction angle margin risk factor based on the predicted arc extinction angle includes:

[0121] Based on the predicted arc extinction angle, the arc extinction angle margin risk factor is determined by a first calculation formula;

[0122] The first calculation formula is shown in the following formula (2):

[0123]

[0124] Among them, R γ is the arc extinction angle margin risk factor, γ th,CE is the predicted arc extinction angle threshold for triggering the commutation enhancement mode; γ predTo predict the arc extinction angle, γ crit is the critical predicted arc extinction angle for triggering the active shutdown mode, γ min_ctrl is the minimum arc extinction angle.

[0125] As an example, combined with the actual hybrid commutation scenario, γ th,CE Can be set to 12°, γ crit Can be set to 5°, γ min_ctrl It can be set to 6°. Under normal system operation, the arc extinction angle margin risk factor R γ Between 0 and 1, if R γ If it is greater than 1, it indicates that the risk of system commutation failure is high.

[0126] According to some embodiments of the present application, optionally, determining the predicted arc extinction angle based on the target firing angle, the DC current, and the commutation reactance of the hybrid commutation valve includes:

[0127] Based on the target trigger angle, DC current and commutation reactance, the predicted arc extinction angle is determined by a second calculation formula;

[0128] The second calculation formula is shown in formula (3):

[0129] γ pred =180°-α-2L c I dc (3)

[0130] Among them, γ pred To predict the arc extinction angle, α is the target trigger angle, I dc is the DC current, L c is the commutation reactance of the hybrid commutation reversing valve.

[0131] According to some embodiments of the present application, optionally, determining the volt-second area margin risk factor based on the net available volt-second area margin includes:

[0132] Based on the net available volt-second area margin, determine the volt-second area margin risk factor using a third calculation formula;

[0133] The third calculation formula is shown in the following formula (4):

[0134]

[0135] Among them, R VSA is the volt-second area margin risk factor, A CE A is the volt-second area margin threshold required to trigger the commutation enhancement mode. γ The critical volt-second area margin required to trigger the active shutdown mode, A net is the net available volt-second area margin.

[0136] Among them, under normal system operation, the volt-second area margin risk factor R VSA The risk increases linearly with the decrease of the net available volt-second area margin, ranging from 0 to 1. If the volt-second area margin risk factor R VSA If it is greater than 1, it indicates that the risk of commutation failure is high.

[0137] According to some embodiments of the present application, optionally, determining the net available volt-second area margin based on the AC voltage, the target firing angle, the DC current, and the commutation reactance includes:

[0138] Based on the AC voltage, target firing angle, DC current, and commutation reactance, the net available volt-second area margin is determined using the fourth calculation formula;

[0139] The fourth calculation formula is shown in the following formula (5):

[0140]

[0141] Among them, A net is the net available volt-second area margin, I dc is the DC current, L c is the commutation reactance, α is the target trigger angle, U L (t) is the AC voltage, and ω is the angular frequency of the hybrid commutation valve. ω can be the real-time angular frequency of the hybrid commutation valve detected by the pole-controlled phase-locked loop.

[0142] In this embodiment, A net It is a key indicator for evaluating the adequacy of commutation drive capability. Its physical meaning is the remaining volt-second area after subtracting the volt-second area actually required by the commutation valve to complete this commutation from the effective commutation volt-second area that the AC system can provide during the current commutation cycle. Therefore, the above formula (5) can achieve an accurate calculation of the net available volt-second area margin.

[0143] In S130 , in a specific implementation, after the arc extinction angle margin risk factor and the volt-second area margin risk factor are calculated, a commutation failure risk index is determined based on the arc extinction angle margin risk factor, the volt-second area margin risk factor and the prediction confidence factor.

[0144] In this step, a prediction confidence factor is introduced into the calculation process of the commutation failure risk index, taking into account possible errors in signal fluctuations, acquisition, and signal conversion and transmission.

[0145] The prediction confidence factor reflects the impact of the AC voltage waveform quality, the severity of dynamic changes, and the reliability of real-time monitoring of AC and DC synchronization signals on the credibility of the prediction results, and can be used to determine the degree of conservatism in modulation risk assessment.

[0146] In specific applications, the prediction confidence factor can be selected based on actual project needs, such as 0.5, 0.8, etc. Low confidence will amplify the risk index and make the strategy more conservative. The lower limit can be set to 0.2 and the upper limit can be set to 1, depending on the actual project needs.

[0147] According to some embodiments of the present application, optionally, determining a commutation failure risk index based on an arc extinction angle margin risk factor, a volt-second area margin risk factor, and a prediction confidence factor includes:

[0148] A commutation failure risk index is determined based on a product of an arc extinction angle margin risk factor and a first weight coefficient, a product of a volt-second area margin risk factor and a second weight coefficient, and a prediction confidence factor.

[0149] In this way, by further introducing the first weight coefficient corresponding to the above-mentioned arc extinction angle margin risk factor and the second weight coefficient corresponding to the volt-second area margin risk factor, the importance of the arc extinction angle and volt-second area in the HCC system in the overall system can be more reasonably reflected, thereby improving the accuracy and reliability of the calculated commutation failure risk index.

[0150] Furthermore, the first weight coefficient and the second weight coefficient may be adjusted according to the actual operating state of the system or changes in external conditions, so that the commutation failure risk index can better adapt to different situations.

[0151] More specifically, determining the commutation failure risk index based on the product of the arc extinction angle margin risk factor and the first weight coefficient, the product of the volt-second area margin risk factor and the second weight coefficient, and the prediction confidence factor includes:

[0152] Determine a commutation failure risk index using a fifth calculation formula based on the product of the arc extinction angle margin risk factor and the first weight coefficient, the product of the volt-second area margin risk factor and the second weight coefficient, and the prediction confidence factor;

[0153] The fifth calculation formula is shown in the following formula (6):

[0154]

[0155] Among them, CFRI is the commutation failure risk index, R γ is the arc extinction angle margin risk factor, R VSA is the volt-second area margin risk factor, W γ is the first weight coefficient, W VSA is the second weight coefficient, C pred is the prediction confidence factor.

[0156] In this way, by calculating the above-mentioned commutation failure risk index, accurate risk quantification and prediction of HCC commutation failure are achieved, so that active intervention can be carried out according to the commutation failure risk index to prevent commutation failure.

[0157] Optionally, the sum of the first weight coefficient and the second weight coefficient is equal to 1. At the same time, considering the importance of the arc extinction angle in achieving reliable commutation and maintaining stable operation of the system in actual commutation scenarios, the first weight coefficient is set to be greater than the second weight coefficient, that is, the first weight coefficient W γ The value of is greater than 0.5 and less than 1. As an example, for the HCC system, in order to highlight the dominance of the arc extinction angle, it is recommended to set it to 0.7 and 0.3 respectively.

[0158] In this way, the dominant role of the arc extinction angle can be fully highlighted when calculating the commutation failure risk index, thereby facilitating a more accurate quantitative prediction of the commutation failure risk based on the commutation failure risk index, which helps to further ensure the safe operation of the system.

[0159] Optionally, the lower limit of the prediction confidence factor is greater than 0, and the upper limit of the prediction confidence factor is 1. If the prediction confidence factor is small, the low confidence will amplify the risk index, making the AC / DC coordinated protection strategy of this application more conservative. As an example, the prediction confidence factor can be set with a lower limit of 0.2 and an upper limit of 1. The specific value can be selected according to actual project needs.

[0160] In S140, during specific implementation, after calculating the above-mentioned commutation failure risk index, if the commutation failure risk index is abnormal, the hybrid commutation valve can be controlled to enter the corresponding commutation enhancement mode or active shutdown mode based on the specific numerical value of the commutation failure risk index.

[0161] The above-mentioned controlled extinction (CE) commutation enhancement mode can be used to improve the reliability and margin of the commutation process of the hybrid commutation valve. In this mode, commutation failure is avoided as much as possible by enhancing the commutation capability.

[0162] The commutation enhancement mode can be triggered by controlling the arc extinction angle to achieve commutation enhancement. In addition, after triggering the commutation enhancement mode, the commutation failure risk index can be continuously monitored to determine whether it is necessary to switch from the commutation enhancement mode to the active shutdown mode.

[0163] The above-mentioned active turn-off mode (ATO) can be used to achieve active shutdown of the hybrid commutation valve by controlling the active shutdown of devices such as IGCT in the hybrid commutation valve, thereby fully utilizing the IGCT's microsecond-level fast shutdown capability to forcibly prevent commutation failure.

[0164] The active shutdown mode triggering can be specifically achieved by controlling the conduction angle locking of the hybrid commutation valve, controlling the sending of gate shutdown instructions, and other operations to achieve precise shutdown control, thereby fully preventing commutation failure, which is not strictly limited here.

[0165] It should be noted that if the above-mentioned commutation failure risk index is normal, the normal operation of the system and the commutation of the HCC can be maintained, and the commutation failure risk index of the system can be calculated continuously or regularly so as to actively intervene in time before the AC or DC fault causes the commutation failure, thereby preventing the commutation failure.

[0166] According to some embodiments of the present application, optionally, when the commutation failure risk index is abnormal, controlling and triggering the hybrid commutation valve to enter the corresponding commutation enhancement mode or active shutdown mode based on the commutation failure risk index includes:

[0167] When the commutation failure risk index is greater than or equal to a first preset threshold, controlling and triggering the hybrid commutation valve to enter an active shutdown mode;

[0168] When the commutation failure risk index is less than a first preset threshold and greater than or equal to a second preset threshold, the hybrid commutation valve is controlled to enter a commutation enhancement mode, wherein the first preset threshold is greater than the second preset threshold.

[0169] In a specific application example, for the HCC system, the first preset threshold corresponding to the active shutdown mode is set to 1, and the second preset threshold corresponding to the commutation enhancement mode is set to 0.3.

[0170] In this embodiment, the HCC triggers either enhanced or active shutdown mode based on the comparison of commutation failure risk index thresholds. This enables a graded response to varying degrees of commutation failure risk under AC / DC faults, enabling proactive intervention before commutation failures caused by AC / DC faults actually occur. The aforementioned CE mode rapidly increases margins to maintain operation, while the ATO mode effectively mitigates commutation failures.

[0171] In this way, through the above-mentioned hierarchical active intervention logic: when a medium risk is identified, the commutation enhancement measures are initiated and the margin is improved by using control flexibility; and when it is determined that the risk has reached a critical level, the control triggers the active shutdown mode, thereby fully resisting the risk of commutation failure.

[0172] To facilitate understanding of the AC / DC fault protection method for a hybrid commutation valve provided in the above embodiment, the above method is described below using a specific scenario embodiment. Figure 2This is a flow chart of a scenario embodiment of an AC / DC fault protection method for a hybrid commutation converter valve provided in one embodiment of the present application, which can be specifically designed for a high-voltage direct current transmission receiving end system.

[0173] This scenario employs a modular parallel architecture, with DC and AC protection functions as independent yet collaborative units. DC protection focuses on rapidly detecting and isolating DC-side faults, using simple and reliable threshold criteria to achieve rapid responses in microseconds to milliseconds. AC protection, on the other hand, comprehensively assesses the commutation failure risk index and triggers preventive control measures when no DC faults are present.

[0174] like Figure 2 As shown in Figure 1, DC protection and AC protection operate in coordination through priority logic: DC faults under DC protection prioritize triggering system blocking, while the commutation failure risk index calculation in AC protection is used to optimize the operation strategy under normal conditions on the DC side.

[0175] Specifically, this scenario embodiment may include the following steps S201-S211:

[0176] S201: Acquire a target monitoring signal of the DC side. The target monitoring signal may include at least one of the DC voltage, the DC voltage change rate, and the DC current change rate of the DC side. In one example, the target monitoring signal includes the DC voltage, the DC voltage change rate, and the DC current change rate of the DC side.

[0177] S202: Determine whether the target monitoring signal meets the DC fault criteria. If so, execute S203 to perform a blocking operation. If not, enter AC protection to begin the commutation failure risk index calculation cycle.

[0178] Specifically, when judging whether the target monitoring signal meets the DC fault criterion, the aforementioned formula (1) can be referred to: by judging whether the above-mentioned DC voltage is less than the DC voltage fault threshold, whether the above-mentioned DC voltage change rate is less than the fault voltage change rate threshold, or whether the above-mentioned DC current change rate is less than the fault current change rate threshold, the DC side fault judgment can be achieved.

[0179] If any parameter is less than its corresponding threshold, the target monitoring signal meets the DC fault criteria. In this case, the DC status signal can be output as a DC fault signal, and a blocking operation can be controlled. Specifically, the blocking operation can include sending a blocking signal to the hybrid commutation valve to stop each switching device from conducting, thereby interrupting the fault current loop; or controlling the disconnector and circuit breaker on the DC side to quickly isolate the fault.

[0180] If the target monitoring signal does not meet the DC fault criteria, the system is in a DC-free state. In this case, subsequent defensive HCC control measures are triggered, and the commutation failure risk index calculation cycle begins. This DC-first, AC-later protection strategy can more effectively ensure the safe operation of the entire AC / DC system and reduce the risk of commutation failure.

[0181] In a specific commutation failure risk index calculation cycle, S204, the AC voltage, target trigger angle, and DC current are obtained. The AC voltage can be, for example, the three instantaneous line voltages on the AC side of the hybrid commutation valve. The AC voltage can be obtained by collecting and feeding back measurement devices such as voltage transformers set on the AC side. The target trigger angle can be, for example, the actual trigger angle of the hybrid commutation valve in its current working state, or the trigger angle that the control system is about to send to the hybrid commutation valve. The DC voltage on the DC side can be obtained by collecting and feeding back measurement devices such as current sensors set on the DC transmission line.

[0182] S205: Calculate and obtain an arc extinction angle margin risk factor and a volt-second area margin risk factor. The arc extinction angle margin risk factor is used to characterize the commutation success margin. The volt-second area margin risk factor characterizes the commutation drive capability and is adaptable to AC voltage distortion. These arc extinction angle margin risk factor and volt-second area margin risk factor can be used to subsequently dynamically quantify the likelihood of commutation failure.

[0183] In the specific calculation, the predicted arc extinction angle is determined based on the target trigger angle, DC current and the commutation reactance of the hybrid commutation valve, and the arc extinction angle margin risk factor is determined based on the predicted arc extinction angle. The calculation method can be found in formulas (2) and (3).

[0184] Furthermore, based on the AC voltage, target trigger angle, DC current and commutation reactance, the net available volt-second area margin is determined, and then the volt-second area margin risk factor is determined based on the net available volt-second area margin. The calculation method can be found in equations (4) and (5).

[0185] S206: Calculate a commutation failure risk index based on the arc extinction angle margin risk factor, the volt-second area margin risk factor, and the prediction confidence factor. This prediction confidence factor reflects the impact of the AC voltage waveform quality, the severity of dynamic changes, and the reliability of the real-time monitoring of the AC and DC synchronization signals on the credibility of the prediction result. It can be used to determine the degree of conservatism in the modulation risk assessment.

[0186] In the specific calculation, by further introducing the first weight coefficient corresponding to the above-mentioned arc extinction angle margin risk factor and the second weight coefficient corresponding to the volt-second area margin risk factor, and combining with the above-mentioned formula (6), the system commutation failure risk index is finally calculated.

[0187] In this way, by calculating the above-mentioned commutation failure risk index, accurate risk quantification and prediction of HCC commutation failure are achieved, and active intervention can be carried out based on the commutation failure risk index to prevent commutation failure.

[0188] S207: Determine whether the commutation failure risk index is greater than or equal to a first preset threshold. If so, execute S208; if not, execute S209. In one example, the first preset threshold is 1.

[0189] S208, controlling and triggering an active shutdown mode. The process ends after executing the active shutdown mode. If the commutation failure risk index is greater than or equal to a first preset threshold, controlling and triggering the hybrid commutation valve to enter the active shutdown mode.

[0190] The above-mentioned active shutdown mode can be used to actively shut down devices such as IGCT in the hybrid commutation valve by controlling the IGCT, thereby fully utilizing the microsecond-level fast shutdown capability of the IGCT to forcibly prevent commutation failure.

[0191] During actual triggering, it can be achieved by controlling the conduction angle locking of the hybrid commutation valve, controlling the sending of gate shutdown instructions, and other operations to achieve precise shutdown control, thereby fully preventing commutation failure, which is not strictly limited here.

[0192] S209: Determine whether the commutation failure risk index is greater than or equal to a second preset threshold. If so, proceed to S210; if not, proceed to the commutation failure risk index calculation cycle. In one example, the second preset threshold is 0.3.

[0193] S210, controlling and triggering a commutation enhancement mode: When the commutation failure risk index is less than a first preset threshold and greater than or equal to a second preset threshold, controlling and triggering the hybrid commutation valve to enter the commutation enhancement mode.

[0194] The above-mentioned commutation enhancement mode can be used to improve the reliability and margin of the commutation process of the hybrid commutation valve. When actually triggered, the commutation enhancement can be achieved by controlling the arc extinction angle increase.

[0195] S211, continuously monitoring the commutation failure risk index. After the commutation enhancement mode is triggered, the commutation failure risk index may be continuously monitored to determine whether it is necessary to switch from the commutation enhancement mode to the active shutdown mode.

[0196] In the embodiment of this scenario, on the one hand, a quantitative calculation method for the risk of commutation failure is introduced, which integrates margin assessment (based on the predicted arc extinction angle and volt-second area margin) and prediction confidence analysis to achieve dynamic and quantitative characterization of the possibility of commutation failure, and provide an accurate and reliable decision-making basis for subsequent graded intervention. Therefore, after calculating the commutation failure risk index, through accurate risk prediction and graded response of the commutation failure risk index, this embodiment can actively intervene before the AC / DC fault causes the commutation failure to actually occur, so as to actively trigger the commutation enhancement mode or the active shutdown mode. The commutation enhancement mode can quickly increase the margin to maintain operation, while the active shutdown mode can fully resist commutation failure.

[0197] On the other hand, through the AC / DC coordinated fault protection mechanism and AC / DC operation priority setting, the precise coordination of AC / DC protection can be fully realized, the fault source can be distinguished more accurately, and the probability of protection misoperation and refusal to operate can be reduced. Its clear operating mode can fully provide a clear and real-time status interface for the HCC AC / DC protection system.

[0198] In addition, it should be added that this embodiment, by combining the accurate prediction of the commutation failure risk index with the fast reverse recovery characteristics of the IGCT, can effectively replace the traditional passive margin that relies on increasing the arc extinction angle reference to ensure commutation safety, thereby allowing the system to operate at a time close to the physical minimum shutdown time under normal operating conditions, forming a dynamic defense line against sudden failures.

[0199] To better understand the engineering value of this embodiment, please refer to the following Figure 3 , Figure 3 This is a schematic diagram of transient responses of relevant parameters under a deep fault provided by an embodiment of the present application. Figure 3 The transient response diagram of the AC voltage, predicted arc extinction angle, CFRI factor (commutation failure risk index), CFRI threshold judgment and trigger signal on the AC side of the embodiment of this solution is shown. The scenario is set as the AC side voltage drops by 0.6pu in 0.1s to verify the AC / DC coordinated protection capability of this application.

[0200] In this embodiment, when a deep fault occurs on the AC side, the sharp drop of the AC voltage immediately leads to the predicted arc extinction angle γ pred Rapid decline, reflecting the factor R of the arc extinction angle margin risk γ (arcing angle margin risk factor) and the factor R reflecting the volt-second area margin risk VSA The volt-second area margin risk factor increases rapidly, so that the CFRI rises rapidly from an initial value close to zero and exceeds the triggering threshold of the active shutdown mode at about t=0.115s. In this case, the embodiment triggers the ATO mode in a timely manner.

[0201] After the ATO mode is started, the downward trend of the arc extinction angle is effectively limited and stabilized at γ crit In the safety area near the critical predicted arc extinction angle (triggering the active shutdown mode), it is always much higher than the minimum arc extinction angle γ required by physics or control. min_ctrl Therefore, this embodiment achieves proactive and preventive prevention of commutation failures through rapid and accurate quantitative assessment of commutation failure risk and timely ATO intervention, utilizing the fast shutdown capability of the IGCT in the HCC, thereby fully improving the operational safety of the system under severe AC faults.

[0202] Based on the AC / DC fault protection method of the hybrid commutation valve provided in the above embodiment, based on the same inventive concept, the present application also provides an AC / DC fault protection device of the hybrid commutation valve corresponding to the AC / DC fault protection method of the hybrid commutation valve. Figure 4 The AC / DC fault protection device of the hybrid commutation valve is introduced in detail.

[0203] Figure 4 The structure diagram of the AC / DC fault protection device of the hybrid commutation valve provided in one embodiment of the present application is shown. The hybrid commutation valve is used to connect the AC side and the DC side; Figure 4 The AC / DC fault protection device 400 for a hybrid commutation valve shown includes:

[0204] A first acquisition module 410 is configured to acquire the AC voltage on the AC side, the target trigger angle of the hybrid commutation valve, and the DC current on the DC side;

[0205] A first determining module 420 is configured to determine an arc extinction angle margin risk factor and a volt-second area margin risk factor based on at least one of the AC voltage, the target trigger angle, and the DC current, wherein the arc extinction angle margin risk factor is used to characterize the commutation success margin, and the volt-second area margin risk factor is used to characterize the commutation drive capability;

[0206] A second determining module 430 is configured to determine a commutation failure risk index based on the arc extinction angle margin risk factor, the volt-second area margin risk factor, and the prediction confidence factor;

[0207] The first trigger module 440 is configured to control and trigger the hybrid commutation valve to enter a corresponding commutation enhancement mode or active shutdown mode based on the commutation failure risk index when the commutation failure risk index is abnormal.

[0208] An AC / DC fault protection device for a hybrid commutation valve, provided in an embodiment of the present application, employs corresponding functional modules to determine an arc extinction angle margin risk factor and a volt-second area margin risk factor based on at least one of the AC voltage, target trigger angle, and DC current. The device then accurately quantifies the commutation failure risk by combining the arc extinction angle margin risk factor, the volt-second area margin risk factor, and the prediction confidence factor. This ultimately yields a commutation risk failure index, achieving a dynamic and quantitative characterization of the likelihood of commutation failure. Based on this commutation risk failure index, the device can accurately and reliably trigger a corresponding commutation enhancement mode or active shutdown mode in the event of an abnormality, thereby enabling effective proactive intervention before an AC / DC fault causes a commutation failure, effectively mitigating the risk of commutation failure and improving the operational safety and stability of the system.

[0209] Based on the AC / DC fault protection method of the hybrid commutation valve provided in the above embodiment, for the same inventive concept, the present application also provides an AC / DC fault protection device of the hybrid commutation valve corresponding to the AC / DC fault protection method of the hybrid commutation valve. Figure 5 The AC / DC fault protection equipment of hybrid commutation valve is introduced in detail.

[0210] See below Figure 5 , Figure 5 It is a structural diagram of an AC / DC fault protection device for a hybrid phase-commutated converter valve provided in one embodiment of the present application.

[0211] The AC / DC fault protection device for a hybrid commutated converter valve may include a processor 501 and a memory 502 storing computer program instructions.

[0212] Specifically, the processor 501 may include a central processing unit (CPU), or an application-specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0213] The memory 502 may include a large capacity memory for data or instructions. By way of example and not limitation, the memory 502 may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive, or a combination of two or more of these. Where appropriate, the memory 502 may include removable or non-removable (or fixed) media. Where appropriate, the memory 502 may be inside or outside the integrated gateway disaster recovery device. In a specific embodiment, the memory 502 is a non-volatile solid-state memory.

[0214] The memory may include read-only memory (ROM), random access memory (RAM), magnetic disk storage media devices, optical storage media devices, flash memory devices, electrical, optical or other physical / tangible memory storage devices. Thus, generally, the memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the method according to an aspect of the present disclosure.

[0215] The processor 501 reads and executes computer program instructions stored in the memory 502 to implement any one of the AC / DC fault protection methods for a hybrid commutation valve in the above embodiments.

[0216] In one example, the AC / DC fault protection device for the data hybrid commutation valve may further include a communication interface 503 and a bus 510. Figure 5 As shown, the processor 501, the memory 502, and the communication interface 503 are connected via a bus 510 and communicate with each other.

[0217] The communication interface 503 is mainly used to implement communication between various modules, devices, units and / or equipment in the embodiments of the present application.

[0218] The bus 510 includes hardware, software, or both, coupling the components of the AC / DC fault protection device of the hybrid commutation valve to each other. By way of example and not limitation, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industrial Standard Architecture (EISA) bus, a Front Side Bus (FSB), a HyperTransport (HT) interconnect, an Industrial Standard Architecture (ISA) bus, an InfiniBand interconnect, a Low Pin Count (LPC) bus, a memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or other suitable buses or a combination of two or more of these. Where appropriate, the bus 510 may include one or more buses. Although the embodiments of the present application describe and illustrate specific buses, the present application contemplates any suitable bus or interconnect.

[0219] The AC / DC fault protection device of the hybrid commutation valve executes the AC / DC fault protection method of the hybrid commutation valve in the embodiment of the present application, thereby realizing the AC / DC fault protection method of the hybrid commutation valve described in the embodiment of the present application.

[0220] In addition, in conjunction with the AC / DC fault protection method for a hybrid commutated converter valve in the above-described embodiments, embodiments of the present application may provide a computer storage medium for implementation. The computer storage medium stores computer program instructions; when executed by a processor, the computer program instructions implement any of the AC / DC fault protection methods for a hybrid commutated converter valve in the above-described embodiments.

[0221] Based on the AC / DC fault protection method for a hybrid phase-commutating converter valve in the above-mentioned embodiments, an embodiment of the present application provides a computer program product. When the instructions in the computer program product are executed by a processor of an electronic device, the electronic device executes the AC / DC fault protection method for a hybrid phase-commutating converter valve provided in any one of the above-mentioned embodiments of the present application.

[0222] It should be understood that the present application is not limited to the specific configurations and processes described above and illustrated in the figures. For the sake of brevity, a detailed description of known methods is omitted here. In the above embodiments, several specific steps are described and illustrated as examples. However, the method process of the present application is not limited to the specific steps described and illustrated. Those skilled in the art can make various changes, modifications, and additions, or change the order of the steps after understanding the spirit of the present application.

[0223] The functional blocks shown in the above-described block diagram can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of the present application are programs or code segments that are used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or a communication link by a data signal carried in a carrier wave. "Machine-readable medium" can include any medium that can store or transmit information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROMs, flash memories, erasable ROMs (EROMs), floppy disks, CD-ROMs, optical disks, hard disks, optical fiber media, radio frequency (RF) links, etc. The code segment can be downloaded via a computer network such as the Internet, an intranet, etc.

[0224] It should also be noted that the exemplary embodiments mentioned in this application describe some methods or systems based on a series of steps or devices. However, this application is not limited to the order of the above steps. In other words, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0225] Aspects of the present disclosure have been described above with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present disclosure. It should be understood that each box in the flowchart and / or block diagram and the combination of each box in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer or other programmable data processing device to produce a machine so that these instructions executed by the processor of the computer or other programmable data processing device enable the implementation of the function / action specified in one or more boxes of the flowchart and / or block diagram. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor or a field programmable logic circuit. It is also understood that each box in the block diagram and / or flowchart and the combination of the boxes in the block diagram and / or flowchart can also be implemented by dedicated hardware that performs the specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0226] The above description is only a specific embodiment of the present application. Those skilled in the art will clearly understand that for the convenience and brevity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the scope of protection of the present application.

Claims

1. A method for AC / DC fault protection of a hybrid commutation valve, characterized in that: The hybrid phase-commutation valve is used to connect the AC side and the DC side; the method includes: Acquiring the AC voltage on the AC side, the target trigger angle of the hybrid commutation valve, and the DC current on the DC side; Determining an arc extinction angle margin risk factor and a volt-second area margin risk factor based on at least one of the AC voltage, the target trigger angle, and the DC current, wherein the arc extinction angle margin risk factor is used to characterize a commutation success margin, and the volt-second area margin risk factor is used to characterize a commutation drive capability; Determining a commutation failure risk index based on the arc extinction angle margin risk factor, the volt-second area margin risk factor, and a prediction confidence factor; In the case where the commutation failure risk index is abnormal, the hybrid commutation valve is controlled and triggered to enter the corresponding commutation enhancement mode or active shutdown mode based on the commutation failure risk index.

2. The method according to claim 1, characterized in that Before acquiring the AC voltage on the AC side, the target trigger angle of the hybrid commutation valve, and the DC current on the DC side, the method further includes: Acquire a target monitoring signal of the DC side, and output a DC state signal according to the target monitoring signal, wherein the target monitoring signal includes at least one of the DC voltage, the DC voltage change rate, and the DC current change rate of the DC side; The acquiring of the AC voltage on the AC side, the target trigger angle of the hybrid commutation valve, and the DC current on the DC side includes: When the DC state signal is a normal signal, the AC voltage, the target trigger angle, and the DC current are acquired.

3. The method according to claim 2, characterized in that The acquiring the target monitoring signal of the DC side and outputting the DC state signal according to the target monitoring signal includes: When the target monitoring signal meets the DC fault criterion, outputting the DC state signal as a DC fault signal; When the target monitoring signal does not meet the DC fault criterion, outputting the DC state signal as the normal signal; The DC fault criterion includes: the DC voltage is less than a DC voltage fault threshold, the DC voltage change rate is less than a fault voltage change rate threshold, or the DC current change rate is less than a fault current change rate threshold.

4. The method according to claim 1, wherein The determining of the arc extinction angle margin risk factor and the volt-second area margin risk factor based on at least one of the AC voltage, the target trigger angle, and the DC current includes: Determining a predicted arc extinction angle based on the target firing angle, the DC current, and the commutation reactance of the hybrid commutation valve, and determining the arc extinction angle margin risk factor based on the predicted arc extinction angle; A net available volt-second area margin is determined based on the AC voltage, the target firing angle, the DC current, and the commutation reactance, and the volt-second area margin risk factor is determined based on the net available volt-second area margin.

5. The method according to claim 4, characterized in that The determining the arc extinction angle margin risk factor based on the predicted arc extinction angle includes: Based on the predicted arc extinction angle, determining the arc extinction angle margin risk factor using a first calculation formula; The first calculation formula includes: Among them, R γ is the arc extinction angle margin risk factor, γ th,CE is the predicted arc extinction angle threshold for triggering the commutation enhancement mode; γ pred is the predicted arc extinction angle, γ crit is the critical predicted arc extinction angle for triggering the active shutdown mode, γ min_ctrl is the minimum arc extinction angle.

6. The method according to claim 4, characterized in that The step of determining a predicted arc extinction angle based on the target trigger angle, the DC current, and the commutation reactance of the hybrid commutation valve includes: Determining the predicted arc extinction angle using a second calculation formula based on the target trigger angle, the DC current, and the commutation reactance; The second calculation formula includes: c pred =180°-α-2L c I dc Among them, γ pred is the predicted arc extinction angle, α is the target trigger angle, I dc is the DC current, L c is the commutation reactance.

7. The method according to claim 4, characterized in that The determining the volt-second area margin risk factor based on the net available volt-second area margin includes: Determining the volt-second area margin risk factor based on the net available volt-second area margin using a third calculation formula; The third calculation formula includes: Among them, R VSA is the volt-second area margin risk factor, A CE A is the volt-second area margin threshold required to trigger the commutation enhancement mode. γ The critical volt-second area margin required to trigger the active shutdown mode, A net is the net available volt-second area margin.

8. The method according to claim 4, characterized in that The determining of a net available volt-second area margin based on the AC voltage, the target firing angle, the DC current, and the commutation reactance includes: Determining the net available volt-second area margin using a fourth calculation formula based on the AC voltage, the target firing angle, the DC current, and the commutation reactance; The fourth calculation formula includes: Among them, A net is the net available volt-second area margin, I dc is the DC current, L c is the commutation reactance, α is the target trigger angle, U L (t) is the AC voltage, and ω is the angular frequency of the hybrid commutation valve.

9. The method according to claim 1, characterized in that Determining a commutation failure risk index based on the arc extinction angle margin risk factor, the volt-second area margin risk factor, and the prediction confidence factor includes: The commutation failure risk index is determined based on the product of the arc extinction angle margin risk factor and a first weight coefficient, the product of the volt-second area margin risk factor and a second weight coefficient, and the prediction confidence factor.

10. The method according to claim 9, characterized in that The determining of the commutation failure risk index based on the product of the arc extinction angle margin risk factor and a first weight coefficient, the product of the volt-second area margin risk factor and a second weight coefficient, and the prediction confidence factor includes: Determining the commutation failure risk index using a fifth calculation formula based on the product of the arc extinction angle margin risk factor and the first weight coefficient, the product of the volt-second area margin risk factor and the second weight coefficient, and the prediction confidence factor; The fifth calculation formula includes: Wherein, CFRI is the commutation failure risk index, R γ is the arc extinction angle margin risk factor, R VSA is the volt-second area margin risk factor, W γ is the first weight coefficient, W VSA is the second weight coefficient, C pred is the prediction confidence factor.

11. The method according to claim 1, wherein In the case where the commutation failure risk index is abnormal, controlling and triggering the hybrid commutation valve to enter a corresponding commutation enhancement mode or active shutdown mode based on the commutation failure risk index includes: When the commutation failure risk index is greater than or equal to a first preset threshold, controlling and triggering the hybrid commutation valve to enter the active shutdown mode; When the commutation failure risk index is less than the first preset threshold and greater than or equal to the second preset threshold, the hybrid commutation valve is controlled to enter the commutation enhancement mode, wherein the first preset threshold is greater than the second preset threshold.

12. An AC / DC fault protection device for a hybrid phase-commutation valve, characterized in that: The hybrid phase-commutation valve is used to connect the AC side and the DC side; the device includes: a first acquisition module, configured to acquire the AC voltage on the AC side, the target trigger angle of the hybrid commutation valve, and the DC current on the DC side; a first determining module, configured to determine an arc extinction angle margin risk factor and a volt-second area margin risk factor based on at least one of the AC voltage, the target trigger angle, and the DC current, wherein the arc extinction angle margin risk factor is used to characterize a commutation success margin, and the volt-second area margin risk factor is used to characterize a commutation drive capability; a second determining module, configured to determine a commutation failure risk index based on the arc extinction angle margin risk factor, the volt-second area margin risk factor, and a prediction confidence factor; The first trigger module is used to control and trigger the hybrid commutation valve to enter the corresponding commutation enhancement mode or active shutdown mode based on the commutation failure risk index when the commutation failure risk index is abnormal.

13. An AC / DC fault protection device for a hybrid phase-commutation valve, characterized in that: The device includes: a processor and a memory storing computer program instructions; When the processor executes the computer program instructions, the AC / DC fault protection method for the hybrid commutation valve is implemented as described in any one of claims 1 to 11.

14. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer program instructions, and when the computer program instructions are executed by a processor, the AC / DC fault protection method for a hybrid commutation valve is implemented according to any one of claims 1 to 11.

15. A computer program product, characterized in that When the instructions in the computer program product are executed by a processor of an electronic device, the electronic device executes the AC / DC fault protection method for a hybrid commutation valve according to any one of claims 1 to 11.

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