Hybrid commutation converter valve operation method and hybrid commutation converter valve

Abstract

The invention relates to a hybrid commutation converter valve operation method and a hybrid commutation converter valve, and the method comprises the steps: obtaining a phase current measurement value of an AC wire inlet of the hybrid commutation converter valve, obtaining the bridge arm conduction state information of the hybrid commutation converter valve, and combining a preset corresponding relation among a bridge arm conduction state, a phase current and a bridge arm current, and obtaining a phase current measurement value of an AC wire inlet of the hybrid commutation converter valve; and analyzing and calculating to obtain the bridge arm current of the current conduction bridge arm. According to the scheme, the bridge arm current of the hybrid commutation converter valve is indirectly obtained by measuring the phase current measurement value of the alternating current wire inlet of the hybrid commutation converter valve and combining the bridge arm conduction state information for analysis, a current sensor does not need to be installed on the bridge arm of the hybrid commutation converter valve, the influence of electromagnetism and vibration is avoided, and the reliability of the hybrid commutation converter valve is improved. And the accuracy of the obtained bridge arm current is ensured. In this way, active turn-off monitoring of the hybrid commutation converter valve is achieved through the bridge arm current with high accuracy, and the operation reliability of the hybrid commutation converter valve is effectively improved.

Description

Technical Field

[0001] The present application relates to the field of commutation technology, and in particular to a hybrid commutation commutation valve operation method and a hybrid commutation commutation valve. Background Art

[0002] With the development of power technology, hybrid commutation valves with active commutation function are gradually being used in high-voltage direct current transmission systems. Hybrid commutation valves generally use IGCT (Integrated Gate Commutated Thyristor) as active shutdown modules. During operation, it is usually necessary to combine the bridge arm current to determine whether active shutdown is required. During the active shutdown process, it is necessary to further combine the bridge arm current to determine whether overcurrent shutdown is required. Therefore, detecting the bridge arm current flowing through the bridge arm is of great significance to the reliable operation of the hybrid commutation valve.

[0003] However, in the related art, due to the complex internal electromagnetic environment and strong vibration of the hybrid commutation valve, it is usually difficult to install the current sensor on the bridge arm of the hybrid commutation valve to collect accurate bridge arm current, and the operating reliability of the hybrid commutation valve is poor. Summary of the invention

[0004] Based on this, it is necessary to provide a hybrid phase-commutation valve operation method and a hybrid phase-commutation valve to obtain accurate bridge arm current, thereby improving the operation reliability of the hybrid phase-commutation valve.

[0005] A hybrid phase-commutation converter valve operation method, comprising: obtaining bridge arm conduction state information of the hybrid phase-commutation converter valve; obtaining phase current measurement values ​​of the AC inlet of the hybrid phase-commutation converter valve; determining the bridge arm current of the currently conducting bridge arm according to the bridge arm conduction state information, the phase current measurement values, and the preset correspondence between the bridge arm conduction state, phase current and bridge arm current; wherein the bridge arm current is used to perform active shutdown monitoring of the hybrid phase-commutation converter valve.

[0006] In one of the embodiments, the hybrid commutation valve operation method further includes: obtaining a DC current measurement value of a DC inlet of the hybrid commutation valve; and performing fault detection on the hybrid commutation valve based on the DC current measurement value and the phase current measurement value.

[0007] In one of the embodiments, the DC current measurement value includes a first-end DC current measurement value and a second-end DC current measurement value, and the phase current measurement value includes a Y-bridge phase current measurement value and a D-bridge phase current measurement value; the hybrid commutation valve fault detection is performed based on the DC current measurement value and the phase current measurement value, including: determining a first phase current maximum value based on an absolute value of the D-bridge phase current measurement value; determining a second phase current maximum value based on an absolute value of the Y-bridge phase current measurement value; and the hybrid commutation valve fault detection is performed based on the first phase current maximum value, the second phase current maximum value, the first-end DC current measurement value, and the second-end DC current measurement value.

[0008] In one of the embodiments, the hybrid commutation valve is subjected to fault detection based on the maximum value of the first phase current, the maximum value of the second phase current, the measured value of the DC current at the first end, and the measured value of the DC current at the second end, including: determining a first criterion condition based on the maximum value of the first phase current, the measured value of the DC current at the first end, and a set value for starting current; determining a second criterion condition based on the maximum value of the first phase current, the maximum value of the second phase current, and the set value for starting current; determining a third criterion condition based on the maximum value of the second phase current, the measured value of the DC current at the second end, and the set value for starting current; and performing fault detection on the hybrid commutation valve based on the first criterion condition, the second criterion condition, and the third criterion condition.

[0009] In one embodiment, the hybrid commutation valve is subjected to fault detection based on the first criterion condition, the second criterion condition and the third criterion condition, including: determining the fault state of the hybrid commutation valve based on the number of triggering criteria and the triggering method in the first criterion condition, the second criterion condition and the third criterion condition.

[0010] In one of the embodiments, the fault state of the hybrid commutation valve is determined according to the number of trigger criteria and the triggering method in the first criterion condition, the second criterion condition and the third criterion condition, including: within one cycle, when the number of trigger criteria in the first criterion condition, the second criterion condition and the third criterion condition is one, the grounding fault type of the hybrid commutation valve is determined according to the criterion triggering method; within one cycle, when the number of trigger criteria in the first criterion condition, the second criterion condition and the third criterion condition is two, the short circuit fault type of the hybrid commutation valve is determined according to the criterion triggering method.

[0011] In one embodiment, the hybrid phase-changing valve operation method includes at least one of the following items: first, the first criterion condition includes: the absolute value of the difference between the maximum value of the first phase current and the measured value of the DC current at the first end is greater than the set starting current value; second, the second criterion condition includes: the absolute value of the difference between the maximum value of the first phase current and the maximum value of the second phase current is greater than the set starting current value; third, the third criterion condition includes: the absolute value of the difference between the maximum value of the second phase current and the measured value of the DC current at the second end is greater than the set starting current value.

[0012] In one embodiment, the method of obtaining the phase current measurement value of the AC inlet of the hybrid phase-commutation valve includes: receiving the current sampling value collected and sent by the phase current acquisition device arranged at the AC inlet of the hybrid phase-commutation valve; wherein, one phase current acquisition device is arranged corresponding to one AC inlet, each of the phase current acquisition devices includes at least two optical fiber current transformers, and each of the optical fiber current transformers collects and obtains a current sampling value; and performing optimal analysis based on each of the current sampling values ​​to determine the phase current measurement value of the AC inlet.

[0013] In one of the embodiments, the preferred analysis based on the current sampling values ​​to determine the phase current measurement value of the AC inlet includes: checking whether each of the current sampling values ​​is abnormal; when at least two of the current sampling values ​​are normal, determining the phase current measurement value of the AC inlet based on the normal current sampling values.

[0014] In one of the embodiments, when at least two of the current sampling values ​​are normal, the phase current measurement value of the AC inlet is determined according to the normal current sampling values, including: when two of the current sampling values ​​are normal, taking the average of the two normal current sampling values ​​as the phase current measurement value of the AC inlet; when more than three of the current sampling values ​​are normal, determining the average of the normal current sampling values, and taking the normal current sampling value with the smallest absolute difference from the average value as the phase current measurement value of the AC inlet.

[0015] In one of the embodiments, before the current sampling value collected and sent by the phase current acquisition device arranged at the AC inlet of the hybrid phase-commutation valve is received, it also includes: obtaining the operating status of each of the optical fiber current transformers in the phase current acquisition device; when at least two of the optical fiber current transformers are normal, executing the step of receiving the current sampling value collected and sent by the phase current acquisition device arranged at the AC inlet of the hybrid phase-commutation valve; when all of the optical fiber current transformers are abnormal or one of the optical fiber current transformers is normal, outputting a prompt message prohibiting active shutdown.

[0016] A hybrid phase-changing valve comprises a bridge arm power unit, a phase current acquisition device and a control device, wherein the phase current acquisition device is arranged at the AC line inlet of the bridge arm power unit, the phase current acquisition device and the bridge arm power unit are respectively connected to the control device, and the control device is used to execute the steps of the above-mentioned hybrid phase-changing valve operation method.

[0017] In one of the embodiments, it further includes a DC current collection device disposed at the DC line inlet of the bridge arm power unit, and the DC current collection device is connected to the control device.

[0018] In one embodiment, the phase current acquisition device and the DC current acquisition device have the same structure, and both include at least two optical fiber current transformers.

[0019] In one embodiment, the control device includes a valve controller, and a first active shutdown judgment chassis and a second active shutdown judgment chassis that are redundant with each other, the phase current acquisition device is connected to the first active shutdown judgment chassis and the second active shutdown judgment chassis respectively, and the first active shutdown judgment chassis and the second active shutdown judgment chassis are connected to the valve controller respectively.

[0020] The hybrid phase-changing converter valve operation method and hybrid phase-changing converter valve obtain the phase current measurement value of the AC inlet of the hybrid phase-changing converter valve and the bridge arm conduction state information of the hybrid phase-changing converter valve, and combine the preset correspondence between the bridge arm conduction state, phase current and bridge arm current to analyze and calculate the bridge arm current of the current conduction bridge arm. This scheme indirectly obtains the bridge arm current of the hybrid phase-changing converter valve by measuring the phase current measurement value of the AC inlet of the hybrid phase-changing converter valve and analyzing it in combination with the bridge arm conduction state information. There is no need to install a current sensor on the bridge arm of the hybrid phase-changing converter valve, and it is not affected by electromagnetic and vibration, ensuring the accuracy of the acquired bridge arm current. In this way, the active shutdown monitoring of the hybrid phase-changing converter valve is realized with the bridge arm current with higher accuracy, effectively improving the operating reliability of the hybrid phase-changing converter valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 This is a flow chart of a hybrid phase-commutation valve operation method in one embodiment of the present application;

[0023] Figure 2 This is a schematic diagram of the topological structure of a hybrid commutation valve in an embodiment of the present application;

[0024] Figure 3 This is a flow chart of a hybrid phase-commutation valve operation method in another embodiment of the present application;

[0025] Figure 4 This is a flow chart of a hybrid phase-commutation valve operation method in another embodiment of the present application;

[0026] Figure 5 This is a schematic diagram of a hybrid commutation valve fault detection process in an embodiment of the present application;

[0027] Figure 6 This is a schematic diagram of a hybrid commutation valve fault detection process in another embodiment of the present application;

[0028] Figure 7 This is a schematic diagram of a phase current measurement value determination process in an embodiment of the present application;

[0029] Figure 8 This is a schematic diagram of a phase current measurement value determination process in another embodiment of the present application;

[0030] Fig. 9 This is a schematic diagram of a phase current measurement value determination process in another embodiment of the present application;

[0031] Fig.10 This is a schematic diagram of a phase current measurement value determination process in yet another embodiment of the present application;

[0032] Fig.11 This is a schematic diagram of the topological structure of a hybrid phase-commutated converter valve in another embodiment of the present application. DETAILED DESCRIPTION

[0033] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0035] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0036] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0037] It can be understood that “at least one” means one or more, “plurality” means two or more, and “at least part of an element” means part or all of an element.

[0038] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0039] The hybrid commutation converter valve operation method provided in the embodiment of the present application is applied to a current source converter valve with a hybrid commutation function (i.e., capable of natural commutation and active commutation), and its detailed structure is not unique and is not specifically limited. In order to facilitate understanding of the technical solution of the present application, the following embodiments are explained by taking a 12-pulse converter valve as an example.

[0040] See also Figure 1 , a hybrid phase-commutation valve operation method, including step 102, step 104 and step 106.

[0041] Step 102, obtaining the bridge arm conduction state information of the hybrid commutation valve.

[0042] Specifically, the bridge arm conduction state information is used to characterize the information of the bridge arm in the conduction state in the hybrid phase-changing valve. In the embodiment of the present application, the hybrid phase-changing valve is equipped with a control device, through which various state parameters of the hybrid phase-changing valve can be obtained during operation, and based on these state parameters, an on-off control signal is sent to the bridge arm power unit of the hybrid phase-changing valve, thereby realizing the commutation function. Therefore, through the control device, information related to the conduction of the bridge arm of the hybrid phase-changing valve can be retrieved, thereby obtaining the bridge arm conduction state information.

[0043] It should be noted that the type of bridge arm conduction state information is not unique. In one embodiment, it may be a bridge arm conduction control signal used to control the bridge arm of the hybrid commutation valve to be turned on and off. In another embodiment, the bridge arm conduction state information may also be the number of the currently turned-on bridge arm, or the commutation state of the commutation valve, etc., which is not specifically limited.

[0044] Step 104, obtaining the phase current measurement value of the AC inlet of the hybrid commutation valve.

[0045] Specifically, the AC inlet is the bridge arm power unit in the hybrid commutation valve, which is used to access the line port on the AC side. In actual scenarios, the number of corresponding AC inlets varies depending on the type of hybrid commutation valve. For example, take the 12-pulse valve as an example. Figure 2 , its bridge arm power unit includes a Y bridge (specifically including VY1, VY2, VY3, VY4, VY5 and VY6 as shown in the figure) and a D bridge (specifically including VD1, VD2, VD3, VD4, VD5 and VD6 as shown in the figure). In the Y bridge, the winding of the converter transformer is usually connected in Y (star); while in the D bridge, the winding of the converter transformer is connected in D (delta) or Y-Δ (star-delta). Therefore, the Y bridge and the D bridge correspond to three AC incoming lines respectively. In the Y bridge or the D bridge, each AC incoming line corresponds to phase A, phase B and phase C respectively. There are a total of 6 phase current measurement values ​​at the AC incoming port, which are represented as IDA, IDB, IDC, and IYA, IYB, IYC. In the actual operating environment, different phase current measurement values ​​can be measured according to the different commutation states of the current hybrid commutation converter valve.

[0046] It should be pointed out that the method for obtaining the phase current measurement value is not unique. In one embodiment, a phase current acquisition device may be provided at the inlet of each AC incoming line, and the phase current acquisition device is connected to the control device. The current sampling values ​​of different phase lines of the D bridge or Y bridge can be acquired through the phase current acquisition device. The control device analyzes and processes the received current sampling values ​​to obtain the phase current measurement value. In another embodiment, after the control device receives the current sampling value, it can directly use the current sampling value as the phase current measurement value, and it can be set according to the actual needs.

[0047] It can be understood that in one embodiment, in order to ensure the accuracy of the phase current measurement value finally obtained, each phase current acquisition device can sample and obtain multiple current sampling values ​​respectively. For each phase line, the control device performs optimal analysis based on the received multiple current sampling values ​​and finally determines the phase current measurement value.

[0048] Step 106, determining the bridge arm current of the currently conducting bridge arm according to the bridge arm conducting state information, the phase current measurement value, and the preset corresponding relationship between the bridge arm conducting state, the phase current and the bridge arm current.

[0049] Specifically, the bridge arm current is used to perform active shutdown monitoring on the hybrid commutation valve. Active shutdown monitoring includes but is not limited to detecting whether the hybrid commutation valve needs to be turned on for active shutdown, and whether overcurrent shutdown occurs during the active shutdown process, etc., which are not specifically limited.

[0050] The control device pre-stores the corresponding relationship between the bridge arm conduction state, the phase current and the bridge arm current, wherein the bridge arm conduction state includes one or more of the bridge arm conduction control signal, the number of the conduction bridge arm and the converter valve state, and is not specifically limited. In one embodiment, the bridge arm conduction state includes the bridge arm conduction control signal, the number of the conduction bridge arm and the converter valve state at the same time. In actual scenarios, only one of the three needs to be obtained as the bridge arm conduction state information, and it is input into the control device together with the phase current measurement value, so that the other two bridge arm conduction states and the bridge arm current of the current conduction bridge arm can be matched.

[0051] In order to facilitate understanding of the technical solution of the present application, the following explanation is also given by taking a 12-pulse converter valve as an example. Figure 2As shown, the VD1 bridge arm and the VD4 bridge arm are connected, and the common end formed is used as the A-phase incoming line terminal of the D bridge, and the bridge arm currents of the two will be determined by the phase current measurement value IDA of the phase incoming line terminal; the VD3 bridge arm and the VD6 bridge arm are connected, and the common end formed is used as the B-phase incoming line terminal of the D bridge, and the bridge arm currents of the two will be determined by the phase current measurement value IDB of the phase incoming line terminal; the VD2 bridge arm and the VD5 bridge arm are connected, and the common end formed is used as the C-phase incoming line terminal of the D bridge, and the bridge arm currents of the two will be determined by the phase current measurement value IDC of the phase incoming line terminal. The VY1 bridge arm and the VY4 bridge arm are connected, and the common end formed is used as the A-phase incoming line terminal of the Y bridge. The bridge arm currents of the two will be determined by the phase current measurement value IYA of the phase incoming line terminal; the VY3 bridge arm and the VY6 bridge arm are connected, and the common end formed is used as the B-phase incoming line terminal of the Y bridge. The bridge arm currents of the two will be determined by the phase current measurement value IYB of the phase incoming line terminal; the VY2 bridge arm and the VY5 bridge arm are connected, and the common end formed is used as the C-phase incoming line terminal of the Y bridge. The bridge arm currents of the two will be determined by the phase current measurement value IYC of the phase incoming line terminal.

[0052] As shown in the following table, the CP signal, that is, the bridge arm conduction control signal, defines the bridge arm currents corresponding to the six bridge arms VD1, VD2, VD3, VD4, VD5 and VD6 as ID1, ID2, ID3, ID4, ID5 and ID6 respectively; and defines the bridge arm currents corresponding to the six bridge arms VY1, VY2, VY3, VY4, VY5 and VY6 as IY1, IY2, IY3, IY4, IY5 and IY6 respectively.

[0053]

[0054] Take the CP signal including VD1 or VD4 as an example. If VD1 is 1 (that is, the VD1 bridge arm is turned on), VD4 is 0 (that is, the VD4 bridge arm is not turned on); accordingly, the bridge arm current ID1 flowing through the VD1 bridge arm is negative IDA, and the bridge arm current flowing through the VD4 bridge arm is 0. If VD1 is 0 (that is, the VD1 bridge arm is not turned on), VD4 is 1 (that is, the VD4 bridge arm is turned on); accordingly, the bridge arm current ID1 flowing through the VD1 bridge arm is 0, and the bridge arm current flowing through the VD4 bridge arm is IDA. When the CP signals of VD1 and VD4 are both 0, the bridge arm current flowing through the VD1 bridge arm and the bridge arm current flowing through the VD4 bridge arm will remain unchanged from the corresponding state of the previous CP signal. For example, if the previous CP signal is VD1=0, VD4=1, and the current CP signal is VD1=0, VD4=0, the corresponding relationship of ID1=0, ID4=IDA remains unchanged; if the previous CP signal is VD1=1, VD4=0, and the current CP signal is VD1=0, VD4=0, the corresponding relationship of ID1=negative IDA, ID4=0 remains unchanged.

[0055] It can be understood that when the bridge arm conduction state information is other, according to the corresponding relationship shown in the above table, the bridge arm current value of each bridge arm can be matched respectively in combination with the phase current measurement value at this time, which will not be repeated here one by one.

[0056] The above hybrid phase-changing converter valve operation method obtains the phase current measurement value of the AC inlet of the hybrid phase-changing converter valve and the bridge arm conduction state information of the hybrid phase-changing converter valve, and combines the preset correspondence between the bridge arm conduction state, phase current and bridge arm current to analyze and calculate the bridge arm current of the current conduction bridge arm. This scheme indirectly obtains the bridge arm current of the hybrid phase-changing converter valve by measuring the phase current measurement value of the AC inlet of the hybrid phase-changing converter valve and analyzing it in combination with the bridge arm conduction state information. There is no need to install a current sensor on the bridge arm of the hybrid phase-changing converter valve, and it is not affected by electromagnetic and vibration, ensuring the accuracy of the acquired bridge arm current. In this way, the active shutdown monitoring of the hybrid phase-changing converter valve is realized with the bridge arm current with higher accuracy, effectively improving the operating reliability of the hybrid phase-changing converter valve.

[0057] See also Figure 3 In one embodiment, the hybrid phase-commutation valve operation method also includes step 302 and step 304.

[0058] Step 302, obtaining a DC current measurement value of a DC inlet of a hybrid commutation valve.

[0059] Step 304: Perform fault detection on the hybrid commutation valve according to the DC current measurement value and the phase current measurement value.

[0060] Specifically, in the DC inlet, i.e., the hybrid commutation valve, the bridge arm power unit is used to access the line port on the DC side. In one embodiment, since there are two lines for the bridge arm power unit to access the DC side, a DC current acquisition device needs to be set at each line port, and the collected current sampling value is sent to the control device, and the DC current measurement value is obtained through analysis by the control device.

[0061] It can be understood that, similar to the phase current acquisition device in the above embodiment, each DC current acquisition device can acquire multiple current sampling values. After receiving the multiple current sampling values, the control device performs optimization analysis and finally determines the DC current measurement value corresponding to each DC inlet.

[0062] After obtaining the DC current measurement value, the control device performs fault analysis in combination with the phase current measurement value to detect whether the hybrid commutation valve is faulty at this time and the specific fault type. In this way, it can be known in time when the hybrid commutation valve is faulty, further improving the operational reliability of the hybrid commutation valve.

[0063] It should be pointed out that the faults of the hybrid phase-changing valve include but are not limited to ground faults and short circuit faults. Taking the 12-pulse valve as an example, the ground fault may include at least one of a twelve-pulse neutral point grounding fault, a DC side grounding fault, a high-voltage bridge (D bridge) neutral point grounding fault, and a low-voltage bridge (Y bridge) neutral point grounding fault; the short circuit fault may include at least one of a high-voltage bridge arm short circuit fault, a low-voltage bridge arm short circuit fault, a high- and low-voltage bridge arm short circuit fault at the same time, a high-voltage bridge phase-to-phase short circuit or three-phase short circuit, a low-voltage bridge phase-to-phase short circuit or three-phase short circuit, a DC side short circuit, a high-voltage bridge upper and lower bridge arm short circuit, and a low-voltage bridge upper and lower bridge arm short circuit, without specific limitation.

[0064] See also Figure 4 In one embodiment, the DC current measurement value includes a first-end DC current measurement value and a second-end DC current measurement value, and the phase current measurement value includes a Y-bridge phase current measurement value and a D-bridge phase current measurement value; step 304 includes step 402, step 404 and step 406.

[0065] Step 402: Determine the maximum value of the first phase current according to the absolute value of the D-bridge phase current measurement value.

[0066] Step 404: determine the maximum value of the second phase current according to the absolute value of the Y-bridge phase current measurement value.

[0067] Step 406, performing fault detection on the hybrid commutation valve according to the maximum value of the first phase current, the maximum value of the second phase current, the measured value of the DC current at the first end, and the measured value of the DC current at the second end.

[0068] Specifically, this embodiment is explained with a 12-pulse converter valve, and the Y-bridge phase current measurement value is also the three phase current measurement value corresponding to the Y bridge of the hybrid phase-commutation converter valve, and the D-bridge phase current measurement value is also the three phase current measurement value corresponding to the D bridge of the hybrid phase-commutation converter valve. As shown in the above embodiment, there are two lines for the bridge arm power unit to access the DC side. Therefore, by measuring each line, the first end DC current measurement value and the second end DC current measurement value can be obtained respectively. After that, the control device analyzes in combination with each D-bridge phase current measurement, and takes the absolute maximum value of the three D-bridge phase current measurements as the first phase current maximum value; analyzes in combination with each Y-bridge phase current measurement, and takes the absolute maximum value of the three Y-bridge phase current measurements as the second phase current maximum value, and combines the first phase current maximum value, the second phase current maximum value, the first end DC current measurement value and the second end DC current measurement value to perform fault detection on the hybrid phase-commutation converter valve.

[0069] The above scheme combines the absolute maximum value of the D-bridge phase current measurement value and the absolute maximum value of the Y-bridge phase current measurement value to perform fault detection on the hybrid commutation valve, and has high fault detection accuracy.

[0070] It is understandable that in other embodiments, fault detection may be performed in other ways, for example, comparing the DC current measurement value with the phase current measurement value, or comparing the Y-bridge phase current measurement with the D-bridge phase current measurement, etc., without specific limitation.

[0071] See also Figure 5 In one embodiment, step 406 includes step 502 , step 504 , step 506 and step 508 .

[0072] Step 502, determining a first criterion condition according to the maximum value of the first phase current, the measured value of the DC current at the first end and the set value of the starting current.

[0073] Step 504, determining a second criterion condition according to the maximum value of the first phase current, the maximum value of the second phase current and the set value of the starting current.

[0074] Step 506, determining a third criterion condition according to the maximum value of the second phase current, the measured value of the DC current at the second end and the set value of the starting current.

[0075] Step 508, performing fault detection on the hybrid commutation valve according to the first criterion condition, the second criterion condition and the third criterion condition.

[0076] Specifically, the starting current setting value is a specific setting value for the current required by the converter valve during the starting process in the high-voltage direct current transmission system, which can generally be set to 0.1pu (per unit value, which can be understood as taking the rated current of the hybrid phase-commutated converter valve as a reference)-0.2pu. The scheme of this embodiment combines the maximum value of the first phase current, the measured value of the first-end DC current and the starting current setting value to establish a first criterion condition for the fault detection of the hybrid phase-commutated converter valve, combines the maximum value of the first phase current, the maximum value of the second phase current and the starting current setting value to establish a second criterion condition for the fault detection of the hybrid phase-commutated converter valve, and combines the maximum value of the second phase current, the measured value of the second-end DC current and the starting current setting value to establish a third criterion condition for the fault detection of the hybrid phase-commutated converter valve.

[0077] After that, the real-time maximum value of the first-phase current, the maximum value of the second-phase current, the first-end DC current measurement value and the second-end DC current measurement value are substituted into the three judgment conditions for judgment and analysis, and the hybrid commutation valve is fault detected based on the final analysis result.

[0078] The above scheme, combined with the three constructed criteria, is used to detect the faults of the hybrid commutation valve, which has high detection convenience.

[0079] See also Figure 6 , in one embodiment, step 508 includes step 602.

[0080] Step 602, determining the fault state of the hybrid commutation valve according to the trigger criteria quantity and trigger mode in the first criterion condition, the second criterion condition and the third criterion condition.

[0081] Specifically, the criterion triggering means satisfying the set criterion conditions. Specifically, the maximum value of the first phase current and the measured value of the DC current at the first end satisfy the set first criterion condition, indicating that the first criterion condition is triggered; the maximum value of the first phase current and the maximum value of the second phase current satisfy the set second criterion condition, indicating that the second criterion condition is triggered; the maximum value of the second phase current and the measured value of the DC current at the second end satisfy the set third criterion condition, indicating that the third criterion condition is triggered. The number of triggering criteria, that is, the number of criteria triggered in the first criterion condition, the second criterion condition, and the third criterion condition, can be one, two, or three. The triggering mode, that is, the mode of triggering different criterion conditions, includes but is not limited to alternating triggering, simultaneous triggering, etc., which are not specifically limited.

[0082] Further, in one of the embodiments, step 602 includes: within one cycle, when the number of triggering criteria in the first criterion condition, the second criterion condition and the third criterion condition is one, determining the grounding fault type of the hybrid commutation valve according to the criterion triggering method; within one cycle, when the number of triggering criteria in the first criterion condition, the second criterion condition and the third criterion condition is two, determining the short circuit fault type of the hybrid commutation valve according to the criterion triggering method.

[0083] In this embodiment, the fault types of the hybrid commutation valve include ground fault type and short circuit fault type. If within one cycle, it is detected that the number of the above three criteria conditions in the hybrid commutation valve is one, then according to the specific triggering method, the type of ground fault occurring at this time is analyzed. If within one cycle, it is detected that the number of the above three criteria conditions in the hybrid commutation valve is two, then according to the specific triggering method, the type of short circuit fault occurring at this time is analyzed. In this way, different fault types are analyzed according to different criteria condition triggering numbers, thereby improving the accuracy of fault analysis.

[0084] In order to facilitate understanding of the technical solution of the present application, the following embodiments are also explained with a 12-pulse converter valve. First, in the same cycle, when the number of criterion triggers is 0, it indicates that the hybrid commutation converter valve has no fault. When the number of criterion triggers is three, that is, in the same cycle, the first criterion condition, the second criterion condition and the third criterion condition are triggered at the same time, it is judged that multiple faults are superimposed at this time.

[0085] When the number of criteria triggered in a cycle is one, the following situations are included: (1) The second criterion condition is triggered alone, and it is judged as a twelve-pulse neutral point grounding fault; (2) The first criterion condition is triggered alone, and it is judged as a DC side grounding fault; (3) The first criterion condition and the second criterion condition are triggered alternately, and it is judged as a high-voltage bridge (D bridge) neutral point grounding fault; (4) The second criterion condition and the third criterion condition are triggered alternately, and it is judged as a low-voltage bridge (Y bridge) neutral point grounding fault.

[0086] When the number of criteria triggered in a cycle is two, the following situations are included: (1) The first criteria condition and the second criteria condition are triggered in the same half cycle, and the other half cycle is not triggered. In this case, it is judged as a high-voltage bridge arm short-circuit fault; (2) The second criteria condition and the third criteria condition are triggered in the same half cycle, and the other half cycle is not triggered. In this case, it is judged as a low-voltage bridge arm short-circuit fault; (3) The first criteria condition, the second criteria condition and the third criteria condition are all triggered in the same cycle, and only two criteria conditions are triggered at the same time. In this case, it is judged as a simultaneous short-circuit fault of the high and low voltage bridge arms; (4) The first criteria condition and the second criteria condition are triggered at the same time in the same cycle, and the current (the output current of the hybrid commutation valve) increases to (5) The second criterion condition and the third criterion condition are triggered simultaneously in the same cycle, and the current increases to more than 2pu, in which case it is judged as a phase-to-phase short circuit or a three-phase short circuit of the high-voltage bridge; (6) The first criterion condition and the third criterion condition are triggered simultaneously in the same cycle, and it is judged as a DC side short circuit fault; (7) The first criterion condition and the second criterion condition are triggered simultaneously in the same cycle, and the current is below 2pu, in which case it is judged as a short circuit fault of the upper and lower bridge arms of the high-voltage bridge; (8) The second criterion condition and the third criterion condition are triggered simultaneously in the same cycle, and the current is below 2pu, in which case it is judged as a short circuit fault of the upper and lower bridge arms of the low-voltage bridge.

[0087] In one of the embodiments, the hybrid phase-changing valve operation method includes at least one of the following items: First, the first criterion condition includes: the absolute value of the difference between the maximum value of the first phase current and the measured value of the DC current at the first end is greater than the set value of the starting current; Second, the second criterion condition includes: the absolute value of the difference between the maximum value of the first phase current and the maximum value of the second phase current is greater than the set value of the starting current; Third, the third criterion condition includes: the absolute value of the difference between the maximum value of the second phase current and the measured value of the DC current at the second end is greater than the set value of the starting current.

[0088] Specifically, the specific types of the first criterion condition, the second criterion condition, and the third criterion condition are not unique, and any type of criterion condition can be used as long as it can reasonably characterize the fault state of the hybrid phase-changing valve. In the solution of this embodiment, the absolute value of the difference between the maximum value of the first phase current and the measured value of the DC current at the first end is greater than the set value of the starting current, which is determined as the first criterion condition. That is, ,in, Indicates the DC current measurement value of the first terminal, Indicates the maximum value of the first phase current, represents the set value of the starting current; correspondingly, when this relationship is established, it is considered that the first criterion is triggered.

[0089] The absolute value of the difference between the maximum value of the first phase current and the maximum value of the second phase current is greater than the set value of the starting current, which is determined as the second criterion condition. ,in, represents the maximum value of the second phase current; correspondingly, when this relationship holds, it is considered that the second criterion is triggered.

[0090] The absolute value of the difference between the maximum value of the second phase current and the measured value of the DC current at the second end is greater than the set value of the starting current, which is determined as the third criterion condition. ,in, represents the measured value of the DC current at the second end; correspondingly, when this relationship holds, it is considered that the third criterion is triggered.

[0091] See also Figure 7 In one embodiment, step 104 includes step 702 and step 704.

[0092] Step 702: receiving current sampling values ​​collected and sent by a phase current collection device disposed at an AC inlet of a hybrid phase-commutation converter valve.

[0093] Step 704, performing optimal analysis based on each current sampling value to determine the phase current measurement value of the AC inlet.

[0094] Specifically, a phase current acquisition device is provided corresponding to an AC incoming port, and each phase current acquisition device includes at least two fiber optic current transformers, and each fiber optic current transformer collects a current sampling value. The phase current measurement value corresponding to each AC incoming port is collected separately, that is, each AC incoming port is provided with a phase current acquisition device. In the same phase current acquisition device, multiple fiber optic current transformers (CT, Current Transformer) are provided, and each fiber optic current transformer can be sampled independently to obtain a current sampling value. In this way, not only can the redundancy of the sampling function of the phase current acquisition device be achieved, but also multiple current sampling values ​​can be combined for optimization to obtain a more accurate phase current measurement value.

[0095] It can be understood that the phase current acquisition device performs real-time sampling at a certain sampling period during the operation of the hybrid commutation valve, which can be 4μs (microseconds) as a sampling period. There is no specific limitation and it can be set according to actual needs. The structure and sampling principle of the DC current acquisition device set at the DC inlet are consistent with those of the phase current acquisition device, and will not be repeated here.

[0096] It should be pointed out that the number of fiber optic current transformers in the same phase current acquisition device is not unique. In one embodiment, it can include three, four, five or even more fiber optic current transformers. In order to facilitate understanding of the technical solution of the present application, the following embodiments can be understood as including four fiber optic current transformers.

[0097] The control device is not limited to the way of performing the optimal analysis based on each current sampling value. In one embodiment, each current sampling value may be combined to perform calculations to obtain the phase current measurement value. In another embodiment, one of the current sampling values ​​may be used as the phase current measurement value, which is not specifically limited.

[0098] The specific structure of the control device is not unique. In one embodiment, the control device includes a valve controller and a first active shutdown judgment chassis and a second active shutdown judgment chassis that are redundant with each other. Each phase current acquisition device is connected to the first active shutdown judgment chassis and the second active shutdown judgment chassis respectively. The active shutdown judgment chassis performs optimal analysis on the current sampling value, obtains the phase current measurement value, and then sends it to the valve controller. In this way, not only can the data processing pressure be alleviated, but also the operational reliability of the control device can be improved through the redundant setting of the active shutdown judgment chassis.

[0099] See also Figure 8 In one embodiment, step 704 includes step 802 and step 804.

[0100] Step 802, checking whether each current sampling value is abnormal.

[0101] Step 804: when at least two current sampling values ​​are normal, determine the phase current measurement value of the AC inlet according to the normal current sampling values.

[0102] Specifically, when the control device performs optimization in combination with the current sampling values, it first needs to check whether each current sampling value is abnormal. When at least two current sampling values ​​are normal, optimization can be performed based on the normal current sampling values ​​to determine the phase current measurement value of the AC inlet. When there are no two normal current sampling values, it may be that each current sampling value is abnormal. In this case, it is considered that the current sampling value collected this time is meaningless, and an abnormal prompt message is output. It may also be that only one current sampling value is normal, in which case optimization cannot be performed, and an abnormal prompt message is also output.

[0103] In the above scheme, when obtaining the current sampling value, each current sampling value needs to be verified first, and the phase current measurement value is determined according to the verification result, so as to further improve the accuracy of the phase current measurement value.

[0104] It should be pointed out that the method of verifying whether each current sampling value is abnormal is not unique. In one embodiment, it can be achieved by determining whether the absolute value of the difference between any two current sampling values ​​among these current sampling values ​​is within the allowable measurement error range.

[0105] Specifically, taking four current sampling values ​​as an example, the four current sampling values ​​are divided into I1, I2, I3, and I4, and A1=|I1-I2|, A2=|I1-I3|, A3=|I1-I4|, A4=|I2-I3|, A5=|I2-I4|, and A6=|I3-I4|. It is assumed that A1, A2, A3, A4, A5, and A6 are all: less than or equal to the measurement error (for example, 25 amperes) is normal, and A1, A2, A3, A4, A5, and A6 are all: greater than the measurement error is abnormal. Whether each current sampling value is normal can be analyzed in combination with the relationship in the following table:

[0106]

[0107] Take three current sampling values ​​as an example. The three current sampling values ​​are I1, I2, and I3. Let A1=|I1-I2|, A2=|I1-I3|, and A3=|I2-I3|. Set A1, A2, and A3 to be: less than or equal to the measurement error, which is normal. Set A1, A2, and A3 to be: greater than the measurement error, which is abnormal. The following table can be used to analyze whether each current sampling value is normal:

[0108]

[0109] Further, taking two current sampling values ​​as an example, the two current sampling values ​​are divided into I1 and I2, and A1=|I1-I2|. Correspondingly, if the analysis shows that A1 is normal, that is, A1 is less than or equal to the measurement error, it is determined that the two current sampling values ​​are normal at this time; if the analysis shows that A1 is abnormal, that is, A1 is greater than the measurement error, it is determined that the two current sampling values ​​are abnormal at this time.

[0110] See also Fig. 9 In one embodiment, step 804 includes step 902 and step 904.

[0111] Step 902: When the two current sampling values ​​are normal, the average value of the two normal current sampling values ​​is used as the phase current measurement value of the AC inlet.

[0112] Step 904, when more than three current sampling values ​​are normal, determine the average value of the normal current sampling values, and use the normal current sampling value with the smallest absolute difference from the average value as the phase current measurement value of the AC inlet.

[0113] Specifically, in the solution of this embodiment, when two current sampling values ​​are normal, the average value is used as the phase current measurement value of the AC inlet; when three or more current sampling values ​​are normal, the data closest to the average value of the normal current sampling values ​​is used as the phase current measurement value of the AC inlet. In this way, according to the different numbers of normal current sampling values, different methods are used to analyze and obtain the phase current measurement value, which can further improve the accuracy of the phase current measurement value.

[0114] See also Fig.10 In one embodiment, before step 702, the method further includes steps 1002 and 1004.

[0115] Step 1002, obtaining the operating status of each optical fiber current transformer in the phase current acquisition device.

[0116] When at least two optical fiber current transformers are normal, step 702 is performed.

[0117] Step 1004: when all the optical fiber current transformers are abnormal or one optical fiber current transformer is normal, output a prompt message prohibiting active shutdown.

[0118] Specifically, the number of current sampling values ​​that can be sampled by the phase current acquisition device is not only related to the number of fiber optic current transformers configured by the phase current acquisition device, but also directly related to the operating status of each fiber optic current transformer. If a fiber optic current transformer fails, the number of output current sampling values ​​will also decrease accordingly.

[0119] Therefore, in order to ensure that the subsequent optimization of the current sampling value can be carried out, the scheme of this embodiment needs to ensure that at least two fiber optic current transformers of the same phase current acquisition device are in normal operation, that is, it is necessary to obtain the operating status of each fiber optic current transformer and perform fault detection on each fiber optic current transformer. When all fiber optic current transformers are abnormal or one fiber optic current transformer is normal, the output prohibits active shutdown prompt information, so that the hybrid phase-changing valve stops active shutdown, reducing the risk of further faults caused by active shutdown.

[0120] It should be pointed out that there is not only one way to determine whether each fiber optic current transformer in the phase current acquisition device is abnormal. In one embodiment, the identification information representing the operating status of the fiber optic current transformer can be obtained. If the status of the fiber optic current transformer is received as no good within a certain time period (for example, 500 μs, corresponding to 125 sampling cycles) or for a certain number of consecutive times, the fiber optic current transformer is considered to be abnormal.

[0121] In another embodiment, it can also be realized by analyzing the current sampling value of the optical fiber current transformer. For example, if a certain optical fiber current transformer determines that the deviation of the current sampling value from the current sampling value of other optical fiber current transformers exceeds the measurement error for 25,000 consecutive times (100 ms, 4 μs once), the optical fiber current transformer is set as abnormal.

[0122] Please refer to Figure 2 The embodiment of the present application also provides a hybrid phase-commutation converter valve, including a bridge arm power unit 20, a phase current collection device 21 and a control device (not shown in the figure), the phase current collection device 21 is arranged at the AC line inlet of the bridge arm power unit 20, the phase current collection device 21 and the bridge arm power unit 20 are respectively connected to the control device, and the control device is used to execute the steps of the above-mentioned hybrid phase-commutation converter valve operation method.

[0123] Specifically, the hybrid phase-changing valve operation method is as shown in the above-mentioned embodiments and drawings, and will not be repeated here. The above-mentioned hybrid phase-changing valve obtains the phase current measurement value of the AC inlet of the hybrid phase-changing valve and the bridge arm conduction state information of the hybrid phase-changing valve, and combines the preset correspondence between the bridge arm conduction state, the phase current and the bridge arm current to analyze and calculate the bridge arm current of the current conduction bridge arm. This scheme indirectly obtains the bridge arm current of the hybrid phase-changing valve by measuring the phase current measurement value of the AC inlet of the hybrid phase-changing valve and analyzing it in combination with the bridge arm conduction state information. There is no need to install a current sensor on the bridge arm of the hybrid phase-changing valve, and it is not affected by electromagnetic and vibration, ensuring the accuracy of the acquired bridge arm current. In this way, the active shutdown monitoring of the hybrid phase-changing valve is realized with the bridge arm current with higher accuracy, effectively improving the operation reliability of the hybrid phase-changing valve.

[0124] Please refer to Fig.11 In one embodiment, it also includes a DC current collection device 22 arranged at the DC line inlet of the bridge arm power unit 20, and the DC current collection device 22 is connected to the control device.

[0125] Specifically, since there are two lines for the bridge arm power unit 20 to access the DC side, a DC current acquisition device 22 needs to be set at each line port to send the collected current sampling value to the control device, which analyzes the DC current measurement value.

[0126] After obtaining the DC current measurement value, the control device performs a fault analysis in combination with the phase current measurement value to detect whether the hybrid commutation valve is faulty at this time, and the specific fault type. In this way, when a hybrid commutation valve fails, it can be known in time, further improving the operating reliability of the hybrid commutation valve.

[0127] In one embodiment, the phase current collection device 21 and the DC current collection device 22 have the same structure, and both include at least two optical fiber current transformers.

[0128] Specifically, a plurality of optical fiber current transformers are provided in the same phase current acquisition device 21 or DC current acquisition device 22, and each optical fiber current transformer can independently perform sampling to obtain a current sampling value. In this way, not only the redundancy of the sampling function can be achieved, but also multiple current sampling values ​​can be combined for optimization to obtain a more accurate phase current measurement value or DC current measurement value.

[0129] In one embodiment, the control device includes a valve controller, and a first active shutdown judgment chassis and a second active shutdown judgment chassis that are redundant with each other. The phase current acquisition device 21 is connected to the first active shutdown judgment chassis and the second active shutdown judgment chassis respectively, and the first active shutdown judgment chassis and the second active shutdown judgment chassis are respectively connected to the valve controller.

[0130] Specifically, each phase current acquisition device 21 is connected to the first active shutdown judgment chassis and the second active shutdown judgment chassis respectively, and the active shutdown judgment chassis performs optimal analysis on the current sampling value, obtains the phase current measurement value, and then sends it to the valve controller. In this way, it can not only relieve the data processing pressure, but also improve the operating reliability of the control device through the redundant setting of the active shutdown judgment chassis.

[0131] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic description of the above terms does not necessarily refer to the same embodiment or example.

[0132] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0133] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A hybrid phase-commutation valve operation method, characterized in that: include: Obtaining the conduction state information of the bridge arm of the hybrid commutation valve; Obtaining a phase current measurement value of an AC inlet of the hybrid commutation valve; The bridge arm current of the currently conducting bridge arm is determined according to the bridge arm conduction state information, the phase current measurement value, and the preset correspondence between the bridge arm conduction state, phase current and bridge arm current; wherein the bridge arm current is used to perform active shutdown monitoring on the hybrid phase-changing valve.

2. The hybrid commutation valve operation method according to claim 1, characterized in that: Also includes: Obtaining a DC current measurement value of a DC inlet of the hybrid commutation valve; Fault detection is performed on the hybrid commutation valve according to the DC current measurement value and the phase current measurement value.

3. The hybrid commutation valve operation method according to claim 2, characterized in that: The DC current measurement value includes a first-end DC current measurement value and a second-end DC current measurement value, and the phase current measurement value includes a Y-bridge phase current measurement value and a D-bridge phase current measurement value; The performing fault detection on the hybrid commutation valve according to the DC current measurement value and the phase current measurement value comprises: Determine the maximum value of the first phase current according to the absolute value of the D bridge phase current measurement value; Determining the maximum value of the second phase current according to the absolute value of the Y-bridge phase current measurement value; Fault detection is performed on the hybrid commutation valve according to the maximum value of the first phase current, the maximum value of the second phase current, the measured value of the DC current at the first end, and the measured value of the DC current at the second end.

4. The hybrid commutation valve operation method according to claim 3, characterized in that: The performing fault detection on the hybrid commutation valve according to the maximum value of the first phase current, the maximum value of the second phase current, the measured value of the DC current at the first end, and the measured value of the DC current at the second end comprises: Determining a first criterion condition according to the maximum value of the first phase current, the measured value of the DC current at the first end and the set value of the starting current; Determining a second criterion condition according to the maximum value of the first phase current, the maximum value of the second phase current and the set starting current value; Determining a third criterion condition according to the maximum value of the second phase current, the measured value of the DC current at the second end and the set value of the starting current; According to the first criterion condition, the second criterion condition and the third criterion condition, fault detection is performed on the hybrid commutation valve.

5. The hybrid commutation valve operation method according to claim 4, characterized in that: The performing fault detection on the hybrid commutation valve according to the first criterion condition, the second criterion condition and the third criterion condition comprises: The fault state of the hybrid commutation valve is determined according to the triggering criterion quantity and the triggering method in the first criterion condition, the second criterion condition and the third criterion condition.

6. The hybrid commutation valve operation method according to claim 5, characterized in that: The determining the fault state of the hybrid commutation valve according to the triggering criteria quantity and triggering mode in the first criterion condition, the second criterion condition and the third criterion condition comprises: In one cycle, when the number of triggering criteria in the first criterion condition, the second criterion condition and the third criterion condition is one, determining the grounding fault type of the hybrid commutation valve according to the criterion triggering mode; In one cycle, when the number of triggering criteria in the first criterion condition, the second criterion condition and the third criterion condition is two, the short-circuit fault type of the hybrid commutation valve is determined according to the criterion triggering mode.

7. The hybrid commutation valve operation method according to claim 4, characterized in that: Include at least one of the following: The first criterion condition includes: the absolute value of the difference between the maximum value of the first phase current and the measured value of the DC current at the first end is greater than the set value of the starting current; The second criterion condition includes: the absolute value of the difference between the maximum value of the first phase current and the maximum value of the second phase current is greater than the set value of the starting current; The third item, the third criterion condition includes: the absolute value of the difference between the maximum value of the second phase current and the measured value of the DC current at the second end is greater than the set value of the starting current.

8. The hybrid commutation valve operation method according to any one of claims 1 to 7, characterized in that: The step of obtaining the phase current measurement value of the AC inlet of the hybrid phase-commutation valve comprises: Receiving the current sampling value collected and sent by the phase current collection device arranged at the AC inlet of the hybrid phase-commutation valve; wherein one phase current collection device is arranged corresponding to one AC inlet, each phase current collection device comprises at least two optical fiber current transformers, and each optical fiber current transformer collects and obtains a current sampling value respectively; An optimal analysis is performed based on each of the current sampling values ​​to determine the phase current measurement value of the AC inlet.

9. The hybrid commutation valve operation method according to claim 8, characterized in that: The performing of optimal analysis according to the current sampling value to determine the phase current measurement value of the AC inlet includes: Checking whether each current sampling value is abnormal; When at least two of the current sampling values ​​are normal, the phase current measurement value of the AC inlet is determined according to the normal current sampling values.

10. The hybrid commutation valve operation method according to claim 9, characterized in that: The step of determining the phase current measurement value of the AC inlet according to the normal current sampling values ​​when at least two of the current sampling values ​​are normal includes: When the two current sampling values ​​are normal, the average value of the two normal current sampling values ​​is used as the phase current measurement value of the AC inlet; When more than three current sampling values ​​are normal, the average value of the normal current sampling values ​​is determined, and the normal current sampling value with the smallest absolute difference from the average value is used as the phase current measurement value of the AC inlet.

11. The hybrid commutation valve operation method according to claim 8, characterized in that: Before receiving the current sampling value collected and sent by the phase current collection device arranged at the AC inlet of the hybrid phase-commutation valve, the method further includes: Acquiring the operating status of each of the optical fiber current transformers in the phase current acquisition device; When at least two of the optical fiber current transformers are normal, the step of receiving the current sampling value collected and sent by the phase current collection device arranged at the AC inlet of the hybrid phase-commutation valve is performed; When all the fiber optic current transformers are abnormal or one of the fiber optic current transformers is normal, an active shutdown prohibition prompt message is output.

12. A hybrid phase-changing flow control valve, characterized in that: It includes a bridge arm power unit, a phase current acquisition device and a control device, wherein the phase current acquisition device is arranged at the AC line inlet of the bridge arm power unit, the phase current acquisition device and the bridge arm power unit are respectively connected to the control device, and the control device is used to execute the steps of the hybrid phase-changing valve operation method described in any one of claims 1-11.

13. The hybrid phase-commutation valve according to claim 12, characterized in that: It also includes a DC current collection device arranged at the DC line inlet of the bridge arm power unit, and the DC current collection device is connected to the control device.

14. The hybrid phase-commutation valve according to claim 13, characterized in that: The phase current acquisition device and the DC current acquisition device have the same structure, and both include at least two optical fiber current transformers.

15. The hybrid phase-commutation valve according to claim 12, characterized in that: The control device includes a valve controller, and a first active shutdown judgment chassis and a second active shutdown judgment chassis that are redundant with each other. The phase current acquisition device is connected to the first active shutdown judgment chassis and the second active shutdown judgment chassis respectively, and the first active shutdown judgment chassis and the second active shutdown judgment chassis are connected to the valve controller respectively.

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