A short-time overvoltage test method and related device for a converter valve half-bridge submodule

Abstract

The present application discloses a short-term overvoltage test method for a converter valve half-bridge submodule and a related device. The method is based on a submodule towing circuit and simultaneously forms a charging current to charge the submodule capacitor through an externally connected capacitor tower test circuit, simulating the DC side submodule capacitor voltage rise state. When a certain voltage is reached, the pressure relief protection branch of the power module is activated, realizing multiple releases of the capacitor surplus energy of the flexible DC converter valve half-bridge submodule and verification of the overvoltage protection function. The test method of the present application has a large short-term energy of the tested submodule, which is similar to the energy discharge state of the engineering submodule. Based on the submodule towing circuit, multiple groups of high-power capacitor towers are used to synthesize multiple single-cycle charging currents, thereby achieving multiple continuous overvoltages and verifying the energy release function and reliability of its pressure relief protection branch.

Description

Technical Field

[0001] The present application relates to the technical field of power transmission and distribution testing, and in particular to a short-time overvoltage testing method for a converter valve half-bridge submodule and related devices. Background Art

[0002] Due to its advantages such as efficient transmission, strong flexibility, and zero commutation failure, HVDC Flexible technology can provide reactive power support for the power grid and is suitable for isolated renewable energy islands without stable power grids. In recent years, the scale of HVDC Flexible projects has continued to expand, and transmission capacity has been significantly increased due to performance upgrades of power devices.

[0003] When a flexible DC grid is connected to a new energy island, if a fault occurs in the receiving AC system, the sending converter station cannot immediately sense the fault and reduce the transmitted power due to the long distance. This will cause the receiving system to accumulate excess surplus energy within tens of milliseconds, and the power transmitted to the receiving grid will suddenly drop. Energy accumulation will occur between the sending and receiving ends, the DC side voltage will be too high, and the sub-module capacitor voltage will rise rapidly, even exceeding the sub-module overvoltage tolerance capability, causing the system to lock out.

[0004] Within tens of milliseconds of a fault occurring on the receiving AC side, the system shuts down, creating a deficit in the AC system's active power, adversely impacting system frequency stability. Therefore, the flexible DC grid is required to have fault ride-through capability, meaning that when an AC system fault occurs, the DC system remains operational and can operate normally and stably.

[0005] By placing overvoltage protection devices at both ends of the DC side of the submodule, the capacitor voltage can be quickly released when a short-term overvoltage is generated by the above-mentioned system fault, and surplus energy can be consumed before the sending-end system reduces power or puts other devices into operation, thereby clearing the short-term overvoltage fault.

[0006] The flexible DC converter valve stores large energy and has high power during short-term overvoltage. Ordinary power supplies cannot simulate its state and action. Therefore, it is urgent to design a short-term overvoltage test method for the flexible DC converter valve half-bridge submodule. Summary of the Invention

[0007] The present application provides a short-time overvoltage test method and related device for a converter valve half-bridge submodule, which is used to verify the performance of the pressure relief protection circuit in multiple releases of the capacitive surplus energy of the flexible DC converter valve half-bridge submodule, as well as the overvoltage protection function.

[0008] In view of this, the first aspect of the present application provides a short-time overvoltage test method for a converter valve half-bridge submodule, which is applied to a test device, wherein the test device includes: a tow circuit, a pressure relief protection branch and a capacitor tower test circuit, wherein the tow circuit includes: a power supply S1, a tested submodule B t , Tested submodule Bt Capacitor, test module P t The capacitor tower test circuit includes: an oscillating circuit for generating a periodic charging current and a capacitor tower charging power supply S2; the towing circuit passes through the tested submodule B t The capacitors are respectively connected in parallel with the pressure relief protection branch and the capacitor tower test circuit;

[0009] Methods include:

[0010] S1, based on the drag loop, the tested submodule B is controlled by the upper level. t Working at rated voltage and current;

[0011] S2, generate charging current through the capacitor tower test circuit to make the tested submodule B t The voltage of the capacitor is increased for a short time, thus simulating the voltage rise state caused by a short-term fault on the DC side;

[0012] S3, when the tested submodule B t When the voltage of the capacitor reaches the overvoltage fault protection threshold voltage, the pressure relief protection branch is controlled to consume energy until the voltage of the tested submodule B is reached. t The voltage of the capacitor drops to the rated voltage;

[0013] S4. Repeat step S3 until a preset number of times is reached, disconnect the capacitor tower charging power supply S2 of the capacitor tower test circuit, and discharge to the ground, thereby ending the test.

[0014] Optionally, the capacitor tower test circuit is: a multi-group oscillation circuit structure;

[0015] Wherein, each of the oscillation circuit structures includes: a capacitor, an adjustable reactor, a thyristor valve and an isolation knife switch.

[0016] Optionally, step S1 includes:

[0017] When the tested submodule B t and the accompanying test submodule P t When both are in the locked state, the energy supply S1 is started to output the minimum energy voltage, so that the tested submodule B t be in normal working condition;

[0018] Increase the output voltage of the energy supply S1, and when it reaches the output voltage of the tested submodule B t When the rated working voltage is reached, unlock the tested submodule B t Run, and increase the current of the drag circuit through the upper control to reach the tested submodule B t Rated operating current.

[0019] Optionally, step S2 includes:

[0020] By adjusting the adjustable reactor and the charging voltage of the capacitor in the capacitor tower test circuit, a single-cycle charging current is generated to make the tested submodule B t The capacitor rises to the overvoltage fault preset protection threshold voltage, thereby triggering the energy dissipation protection branch action, and by sequentially triggering the thyristor valves of each branch of the capacitor tower test circuit, a periodic charging current is generated, thereby causing the tested sub-module B to t The voltage of the capacitor rises and the pressure relief protection branch operates and releases energy.

[0021] The second aspect of the present application provides a converter valve half-bridge submodule short-time overvoltage test system, which is applied to a test device, wherein the test device includes: a towing circuit, a pressure relief protection branch and a capacitor tower test circuit, wherein the towing circuit includes: a power supply S1, a tested submodule B t , Tested submodule B t Capacitor, test module P t The capacitor tower test circuit includes: an oscillating circuit for generating a periodic charging current and a capacitor tower charging power supply S2; the towing circuit passes through the tested submodule B t The capacitors are respectively connected in parallel with the pressure relief protection branch and the capacitor tower test circuit;

[0022] The system includes:

[0023] The first control unit is used to control the tested submodule B based on the pair-pulling circuit through the upper control t Working at rated voltage and current;

[0024] The second control unit is used to generate a charging current through the capacitor tower test circuit to make the tested submodule B t The voltage of the capacitor is increased for a short time, thus simulating the voltage rise state caused by a short-term fault on the DC side;

[0025] The third control unit is used to serve as the tested submodule B t When the voltage of the capacitor reaches the overvoltage fault protection threshold voltage, the pressure relief protection branch is controlled to consume energy until the voltage of the tested submodule B is reached. t The voltage of the capacitor drops to the rated voltage;

[0026] The fourth control unit is used to trigger the third control unit until a preset number of times is reached, disconnect the capacitor tower charging power supply S2 of the capacitor tower test circuit, and discharge to the ground, thereby ending the test.

[0027] Optionally, the capacitor tower test circuit is: a multi-group oscillation circuit structure;

[0028] Wherein, each of the oscillation circuit structures includes: a capacitor, an adjustable reactor, a thyristor valve and an isolation knife switch.

[0029] Optionally, the first control unit is specifically configured to:

[0030] When the tested submodule B t and the accompanying test submodule P t When both are in the locked state, the energy supply S1 is started to output the minimum energy voltage, so that the tested submodule B t be in normal working condition;

[0031] Increase the output voltage of the energy supply S1, and when it reaches the output voltage of the tested submodule B t When the rated working voltage is reached, unlock the tested submodule B t Run, and increase the current of the drag circuit through the upper control to reach the tested submodule B t Rated operating current.

[0032] Optionally, the second control unit is specifically configured to:

[0033] By adjusting the adjustable reactor and the charging voltage of the capacitor in the capacitor tower test circuit, a single-cycle charging current is generated to make the tested submodule B t The capacitor rises to the overvoltage fault preset protection threshold voltage, thereby triggering the energy dissipation protection branch action, and by sequentially triggering the thyristor valves of each branch of the capacitor tower test circuit, a periodic charging current is generated, thereby causing the tested sub-module B to t The voltage of the capacitor rises and the pressure relief protection branch operates and releases energy.

[0034] A third aspect of the present application provides a converter valve half-bridge submodule short-time overvoltage test device, the device comprising a processor and a memory:

[0035] The memory is used to store program code and transmit the program code to the processor;

[0036] The processor is configured to execute the steps of the converter valve half-bridge submodule short-time overvoltage test method as described in the first aspect according to the instructions in the program code.

[0037] In a fourth aspect, the present application provides a computer-readable storage medium for storing program code, wherein the program code is used to execute the short-time overvoltage test method for the converter valve half-bridge submodule described in the first aspect.

[0038] It can be seen from the above technical solutions that this application has the following advantages:

[0039] The embodiment of the present application provides a short-term overvoltage test method for a converter valve half-bridge submodule. The method is based on a submodule towing circuit and simultaneously forms a charging current to charge the submodule capacitor through an externally connected capacitor tower test circuit, simulating the DC side submodule capacitor voltage rise state. When a certain voltage is reached, the pressure relief protection branch of the power module is activated, thereby realizing multiple releases of the capacitor surplus energy of the flexible DC converter valve half-bridge submodule and verifying the overvoltage protection function. The test method of the present application has a large short-term energy of the tested submodule, which is similar to the energy discharge state of the engineering submodule. Based on the submodule towing circuit, multiple groups of high-power capacitor towers are used to synthesize a periodic charging current, thereby realizing multiple continuous overvoltage energy release functions and verifying the reliability of its pressure relief protection branch. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Schematic diagram of a flow chart of a short-time overvoltage test method for a converter valve half-bridge submodule provided in an embodiment of the present application;

[0041] Figure 2 This is a schematic diagram of the flexible DC converter valve half-bridge submodule pairing principle provided in an embodiment of the present application;

[0042] Figure 3 This is a schematic diagram of a method for generating periodic charging current for a high-voltage, high-power capacitor tower provided in an embodiment of the present application;

[0043] Figure 4 Provides a periodic charging current waveform for a high-voltage, high-power capacitor tower in an embodiment of the present application;

[0044] Figure 5 Schematic diagram of the structure of a converter valve half-bridge submodule short-time overvoltage test system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0045] In order to help those skilled in the art better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0046] See also Figures 1 to 3 In the embodiment of the present application, a short-time overvoltage test method for a converter valve half-bridge submodule is provided, which is applied to a test device. The test device includes: a towing circuit, a pressure relief protection branch, and a high-power capacitor tower test circuit. The towing circuit includes: a power supply S1, a tested submodule B t , Tested submodule B t Capacitor, test module Pt The capacitor tower test circuit includes: an oscillating circuit for generating a periodic charging current and a capacitor tower charging power supply S2; the towing circuit passes through the tested submodule B t The capacitors are connected in parallel with the pressure relief protection branch and the capacitor tower test circuit respectively.

[0047] In one embodiment, the capacitor tower test circuit is: multiple groups of oscillation circuit structures; wherein each of the oscillation circuit structures includes: a capacitor, an adjustable reactor, a thyristor valve and an isolation knife switch.

[0048] It should be noted that the test device Figure 2 As shown, the submodule rated voltage / current operating state is achieved through the towing platform. The towing circuit includes the energy supply S1 and the tested submodule B. t , Accompanying test module P t And inductor L; adjustable DC energy supply S1 is connected in parallel with the test submodule P t And the tested submodule B t At both ends of the capacitor, the midpoints of the outputs of the two sub-module bridge arms are connected through the inductor L.

[0049] Tested submodule B t The two ends of the capacitor are connected in parallel with the pressure relief protection branch and the capacitor tower test circuit (high voltage and high power capacitor tower test system), that is, the towing circuit is connected through the tested sub-module B. t The capacitor is connected in parallel with the pressure relief protection branch and the capacitor tower test circuit.

[0050] like Figure 3 As shown, the tested submodule B t A high-voltage and high-power capacitor tower test circuit is connected in parallel at both ends of the capacitor. The capacitor tower test circuit generates a periodic charging current through multiple LC oscillation circuits of the capacitor tower to simulate the DC side voltage rise process, including: capacitors C1, C2, C3...Cn of the high-voltage and high-power capacitor tower, adjustable reactors L1, L2, L3...Ln, thyristor valves V1, V2, V3...Vn, isolation switch K V1 , K V2 , K V3 ···Kvn; Each LC oscillation circuit has the same parameters and structure. Taking the capacitor tower L1 / C1 branch as an example, the capacitor tower charging power supply S2 (such as Figure 3 Us in the high voltage end is connected to the isolation switch K S1 Then connect the current limiting resistor R1 and the isolation switch K in series. R1 The high voltage end of capacitor C1 is connected in series with adjustable reactor L1, thyristor valve V1, and isolation knife switch K V1 Then it is connected to the high voltage end of the capacitor C of the tested submodule, the capacitor tower charging power supply S2, the low voltage end of the capacitor C1, the low voltage end of the current limiting resistor R1, and the tested submodule B.t The low voltage end is connected to the primary grounding terminal of the test circuit.

[0051] Methods include:

[0052] Step 101: Based on the drag loop, the upper control makes the tested submodule B t Work at rated voltage and current.

[0053] It should be noted that upper control refers to control through the upper computer issuing control commands.

[0054] like Figure 2 and Figure 3 As shown, in one embodiment, step 101 includes:

[0055] When the tested submodule B t and the accompanying test module P t When both are in the locked state, start the energy supply S1 to output the minimum energy voltage, so that the tested submodule B t be in normal working condition;

[0056] Increase the output voltage of the energy supply S1, and when it reaches the tested sub-module B t When the rated working voltage is reached, unlock the tested submodule B t Run, and increase the current of the drag circuit through the upper control to reach the tested submodule B t Rated operating current.

[0057] Step 102: Generate a charging current through the oscillation circuit in the capacitor tower test circuit to make the tested submodule B t The voltage of the capacitor increases briefly, thereby simulating the voltage rise state caused by a short-term fault on the DC side.

[0058] In one embodiment, step 102 includes:

[0059] By adjusting the adjustable reactor in the capacitor tower test circuit and the charging voltage of the capacitor, a single-cycle charging current is generated to make the tested submodule B t The capacitor rises to the overvoltage fault preset protection threshold voltage, thereby triggering the energy dissipation protection branch action, and by sequentially triggering the thyristor valves of each branch of the capacitor tower test circuit, a periodic charging current is generated, thereby causing the tested sub-module B to t The voltage of the capacitor rises multiple times and the pressure relief protection branch operates multiple times and releases energy.

[0060] It should be noted that if Figure 2 and Figure 3 As shown:

[0061] Adjust the size of the adjustable reactor L1 to meet the test conditions and close the isolation switch K.S1 and K R1 , adjust the DC charging voltage of the capacitor tower charging power supply S2, charge the capacitor C1 of the capacitor tower, and disconnect the isolation switch K after reaching the preset test voltage. S1 and K R1 ;

[0062] Charging current trigger event method: Close the isolation switch K V1 , triggering the thyristor valve V1 to conduct forward, the capacitor C1 of the capacitor tower, the adjustable reactor L1, and the thyristor valve V1 form a DC circuit to generate a charging current; at a certain interval, V1-V2-V3···Vn are triggered in sequence to form a periodic charging current. The charging current of the capacitor tower is fed to the tested sub-module B. t Capacitor C is charged.

[0063] Step 103: When the tested submodule B t When the voltage of the capacitor rises to the overvoltage fault protection threshold voltage, the pressure relief protection branch is controlled to consume energy until the tested submodule B is reached. t The voltage across the capacitor drops to the rated voltage.

[0064] It should be noted that when the tested submodule B t The voltage of the capacitor is increased to the overvoltage fault protection threshold voltage U 导通 When the test submodule B is triggered t The pressure relief protection branch is put into operation, and the capacitor energy is released through the circuit, thereby achieving rapid clearance of overvoltage faults, and the submodule capacitor voltage is reduced. When the capacitor voltage drops to the rated voltage U 额定 When the voltage is 0, the pressure relief protection branch stops working, terminates the energy discharge operation, and waits for the next charging current to arrive, and the tested sub-module continues to rise.

[0065] Step 104: Repeat step 103 until a preset number of times is reached, disconnect the capacitor tower charging power supply S2 of the capacitor tower test circuit, and discharge to the ground, thereby ending the test.

[0066] It should be noted that step 103 is repeated to clear the fault until the actual test requirements are met. The capacitor tower charging power supply S2 is then disconnected, discharged to ground, and the submodule in the tow circuit is restored to its rated voltage and current state. The circuit current and the voltage of the energy supply S1 are sequentially reduced, and the energy supply S1 is disconnected, discharged to ground, and the submodule capacitor is discharged to ground, completing the test.

[0067] The following is a specific test example provided in the examples of this application:

[0068] 1) Pre-treatment before the test: conditioning Figure 3The size of the adjustable reactors L1, L2, L3, etc., Cn in some parts should be adjusted so that the bottom width of the single-cycle charging current waveform meets 20ms. Figure 3 The DC output voltage Us of the medium-high voltage and high-power capacitor tower charging power supply S2 changes the peak value of the charging current. The short-term charging energy can meet the requirements of raising the capacitor voltage of the tested sub-module from the rated voltage to the threshold voltage.

[0069] Single cycle charging current oscillation width:

[0070] ;

[0071] Single cycle charging current peak:

[0072] ;

[0073] 2) Based on the submodule drag circuit, after the submodule is unlocked and running, the upper control is used to make the voltage and current of the tested submodule reach the rated value;

[0074] 3) Based on the high-voltage and high-power capacitor tower test circuit, close the isolation switch K S1 and K R1 , adjust the DC charging voltage Us of the capacitor tower charging power supply S2 to charge the capacitor C1 of the capacitor tower. After reaching the test preset voltage, disconnect the isolation switch K S1 and K R1 ;

[0075] 4) Charging current generation method: triggering thyristor valve V1, capacitor tower capacitor C1, adjustable reactor L1, thyristor V1 and isolation knife switch K V1 A loop is formed to generate a single-cycle charging current;

[0076] 5) Trigger the thyristor valves V1, V2, V3, and Vn in sequence at intervals, such as Figure 4 As shown, a periodic charging current is generated, and the charging energy causes the capacitor voltage of the tested submodule to increase from the rated voltage U 额定 Raised to the threshold voltage U 导通 ; Due to the certain fluctuation of the capacitor voltage of the tested submodule in the drag circuit, the threshold voltage U 导通 Further settings are:

[0077] ;

[0078] Among them, m is the conduction margin, which is specified as 30%~35%;

[0079] 6) When the capacitor voltage of the tested submodule is detected to be close to the shutdown threshold voltage U 关断, the charging current is naturally turned off, the pressure relief protection branch stops working, and the overvoltage fault protection state is exited. When the next cycle charging current arrives, the submodule capacitor voltage rises again, and the tested submodule B t The pressure relief protection branch is put into operation again and the fault clearing operation is repeated;

[0080] Furthermore, the cut-off voltage is specified as:

[0081] ;

[0082] Among them, U 关断 is the test power supply charging current shutdown voltage, n is the shutdown margin, which is specified as 0%~5%;

[0083] 7) Disconnect the capacitor tower charging power supply S2, discharge it to ground, and restore the submodule in the towing circuit to the rated voltage and current state; reduce the current in the circuit and the voltage of the energy source S1 in turn, disconnect the energy source S1, discharge it to ground, and the submodule capacitor is grounded and discharged, and the test is completed.

[0084] The embodiment of the present application provides a short-term overvoltage (fault clearing) test method for a flexible DC converter valve half-bridge submodule. The method is based on a submodule towing circuit and simultaneously forms a charging current to charge the submodule capacitor through an externally connected capacitor tower test circuit, simulating the DC side submodule capacitor voltage rise state. When a certain voltage is reached, the pressure relief protection branch of the power module is activated, achieving multiple releases of surplus energy in the capacitor of the flexible DC converter valve half-bridge submodule and verification of the overvoltage protection function. The test method of the present application has a large short-term energy of the tested submodule, which is similar to the energy discharge state of the engineering submodule. Based on the submodule towing circuit, multiple groups of high-power capacitor towers are used to synthesize a periodic charging current, thereby achieving multiple continuous overvoltage energy release functions and verifying the reliability of its pressure relief protection branch.

[0085] The above is a short-time overvoltage test method for a converter valve half-bridge submodule provided in an embodiment of the present application. The following is a short-time overvoltage test system for a converter valve half-bridge submodule provided in an embodiment of the present application.

[0086] See also Figure 5 In the embodiment of the present application, a short-time overvoltage test system for a converter valve half-bridge submodule is provided, which is applied to a test device. The test device includes: a towing circuit, a pressure relief protection branch, and a capacitor tower test circuit. The towing circuit includes: a power supply S1, a tested submodule B t , Tested submodule B t Capacitor, test module P t The capacitor tower test circuit includes: an oscillating circuit for generating a periodic charging current and a capacitor tower charging power supply S2; the towing circuit passes through the tested submodule B tThe capacitors are connected in parallel with the pressure relief protection branch and the capacitor tower test circuit respectively.

[0087] The system includes:

[0088] The first control unit 201 is used to control the tested submodule B based on the drag loop through the upper control t Work at rated voltage and current.

[0089] The second control unit 202 is used to generate a charging current through the oscillation circuit in the capacitor tower test circuit to make the tested submodule B t The voltage of the capacitor increases briefly, thereby simulating the voltage rise state caused by a short-term fault on the DC side.

[0090] The third control unit 203 is used to serve as the tested submodule B t When the voltage of the capacitor rises to the overvoltage fault protection threshold voltage, the pressure relief protection branch is controlled to consume energy until the tested submodule B is reached. t The voltage across the capacitor drops to the rated voltage.

[0091] The fourth control unit 204 is configured to trigger the third control unit 203 until a preset number of times is reached, disconnect the capacitor tower charging power supply S2 of the capacitor tower test circuit, and discharge to the ground, thereby ending the test.

[0092] Furthermore, an embodiment of the present application also provides a converter valve half-bridge submodule short-time overvoltage test device, the device including a processor and a memory:

[0093] The memory is used to store program code and transmit the program code to the processor;

[0094] The processor is configured to execute the steps of the converter valve half-bridge submodule short-time overvoltage test method as described in the above method embodiment according to the instructions in the program code.

[0095] Furthermore, a computer-readable storage medium is provided in an embodiment of the present application, wherein the computer-readable storage medium is used to store program code, and the program code is used to execute the short-time overvoltage test method for the converter valve half-bridge submodule described in the above method embodiment.

[0096] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0097] The terms "first," "second," "third," "fourth," and the like (if any) in the specification of the present application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0098] It should be understood that in this application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships can exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or plural.

[0099] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0100] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0101] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0102] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (full name: Read-Only Memory, English abbreviation: ROM), random access memory (full name: Random Access Memory, English abbreviation: RAM), disk or optical disk, and other media that can store program code.

[0103] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A short-time overvoltage test method for a converter valve half-bridge submodule, characterized in that: Applied to the test device, the test device includes: a towing circuit, a pressure relief protection branch and a capacitor tower test circuit, wherein the towing circuit includes: a supplementary power supply S1, a tested submodule B t , Tested submodule B t Capacitor, test submodule P t The capacitor tower test circuit includes: an oscillating circuit for generating a periodic charging current and a capacitor tower charging power supply S2; the towing circuit passes through the tested submodule B t The capacitors are respectively connected in parallel with the pressure relief protection branch and the capacitor tower test circuit; Methods include: S1, based on the drag loop, the tested submodule B is controlled by the upper level. t Working at rated voltage and current; S2, generate charging current through the capacitor tower test circuit to make the tested submodule B t The voltage of the capacitor is increased for a short time, thus simulating the voltage rise state caused by a short-term fault on the DC side; S3, when the tested submodule B t When the voltage of the capacitor reaches the overvoltage fault protection threshold voltage, the pressure relief protection branch is controlled to consume energy until the voltage of the tested submodule B is reached. t The voltage of the capacitor drops to the rated voltage; S4. Repeat step S3 until a preset number of times is reached, disconnect the capacitor tower charging power supply S2 of the capacitor tower test circuit, and discharge to the ground, thereby ending the test.

2. The converter valve half-bridge submodule short-time overvoltage test method according to claim 1, characterized in that: The capacitor tower test circuit is: a multi-group oscillation circuit structure; Wherein, each of the oscillation circuit structures includes: a capacitor, an adjustable reactor, a thyristor valve and an isolation knife switch.

3. The converter valve half-bridge submodule short-time overvoltage test method according to claim 1, characterized in that: Step S1 includes: When the tested submodule B t and the accompanying test submodule P t When both are in the locked state, the energy supply S1 is started to output the minimum energy voltage, so that the tested submodule B t be in normal working condition; Increase the output voltage of the energy supply S1, and when it reaches the output voltage of the tested submodule B t When the rated working voltage is reached, unlock the tested submodule B t Run, and increase the current of the drag circuit through the upper control to reach the tested submodule B t Rated operating current.

4. The converter valve half-bridge submodule short-time overvoltage test method according to claim 2, characterized in that: Step S2 includes: By adjusting the adjustable reactor and the charging voltage of the capacitor in the capacitor tower test circuit, a single-cycle charging current is generated to make the tested submodule B t The capacitor rises to the overvoltage fault preset protection threshold voltage, thereby triggering the energy dissipation protection branch action, and by sequentially triggering the thyristor valves of each branch of the capacitor tower test circuit, a periodic charging current is generated, thereby causing the tested sub-module B to t The voltage of the capacitor rises and the pressure relief protection branch operates and releases energy.

5. A converter valve half-bridge submodule short-time overvoltage test system, characterized in that: Applied to the test device, the test device includes: a towing circuit, a pressure relief protection branch and a capacitor tower test circuit, wherein the towing circuit includes: a supplementary power supply S1, a tested submodule B t , Tested submodule B t Capacitor, test module P t The capacitor tower test circuit includes: an oscillating circuit for generating a periodic charging current and a capacitor tower charging power supply S2; the towing circuit passes through the tested submodule B t The capacitors are respectively connected in parallel with the pressure relief protection branch and the capacitor tower test circuit; The system includes: The first control unit is used to control the tested submodule B based on the pair-pulling circuit through the upper control t Working at rated voltage and current; The second control unit is used to generate a charging current through the capacitor tower test circuit to make the tested submodule B t The voltage of the capacitor is increased for a short time, thus simulating the voltage rise state caused by a short-term fault on the DC side; The third control unit is used to serve as the tested submodule B t When the voltage of the capacitor reaches the overvoltage fault protection threshold voltage, the pressure relief protection branch is controlled to consume energy until the voltage of the tested submodule B is reached. t The voltage of the capacitor drops to the rated voltage; The fourth control unit is used to trigger the third control unit until a preset number of times is reached, disconnect the capacitor tower charging power supply S2 of the capacitor tower test circuit, and discharge to the ground, thereby ending the test.

6. The converter valve half-bridge submodule short-time overvoltage test system according to claim 5, characterized in that: The capacitor tower test circuit is: a multi-group oscillation circuit structure; Wherein, each of the oscillation circuit structures includes: a capacitor, an adjustable reactor, a thyristor valve and an isolation knife switch.

7. The converter valve half-bridge submodule short-time overvoltage test system according to claim 5, characterized in that: The first control unit is specifically configured to: When the tested submodule B t and the accompanying test submodule P t When both are in the locked state, the energy supply S1 is started to output the minimum energy voltage, so that the tested submodule B t be in normal working condition; Increase the output voltage of the energy supply S1, and when it reaches the output voltage of the tested submodule B t When the rated working voltage is reached, unlock the tested submodule B t Run, and increase the current of the drag circuit through the upper control to reach the tested submodule B t Rated operating current.

8. The converter valve half-bridge submodule short-time overvoltage test system according to claim 6, characterized in that: The second control unit is specifically configured to: By adjusting the adjustable reactor and the charging voltage of the capacitor in the capacitor tower test circuit, a single-cycle charging current is generated to make the tested submodule B t The capacitor rises to the overvoltage fault preset protection threshold voltage, thereby triggering the energy dissipation protection branch action, and by sequentially triggering the thyristor valves of each branch of the capacitor tower test circuit, a periodic charging current is generated, thereby causing the tested sub-module B to t The voltage of the capacitor rises and the pressure relief protection branch operates and releases energy.

9. A converter valve half-bridge submodule short-time overvoltage test equipment, characterized in that: The device includes a processor and a memory: The memory is used to store program code and transmit the program code to the processor; The processor is configured to execute the converter valve half-bridge submodule short-time overvoltage test method according to any one of claims 1 to 4 according to the instructions in the program code.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium is used to store program code, and the program code is used to execute the short-time overvoltage test method for the converter valve half-bridge submodule according to any one of claims 1 to 4.

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