A method, device, equipment and medium for destructive test of flexible HVDC converter valve

Abstract

The application discloses a kind of flexible direct current converter valve destructive test method, device, equipment and medium, first, according to the long-term current-carrying capacity of IGBT device in flexible direct current converter valve submodule, IGBT test product submodule is constructed;It includes IGBT test product submodule with long-term current-carrying capacity and IGBT test product submodule without long-term current-carrying capacity;Second, the two test product submodules are respectively subjected to up and down IGBT straight-through destructive test, the test product submodule with long-term current-carrying capacity is subjected to bypass switch miscombination destructive test, and the two test product submodules are respectively subjected to bypass switch refusal destructive test;Finally, the explosion-proof performance of the flexible direct current converter valve is judged according to the test phenomenon of the above test, and the test result is obtained.The application can better meet the needs of flexible direct current converter valve destructive test and improve the reliability of test result.

Description

Technical Field

[0001] This invention relates to the field of flexible DC transmission technology, and in particular to a destructive testing method, apparatus, equipment, and medium for flexible DC converter valves. Background Technology

[0002] Flexible DC transmission (VSC-HVDC, Voltage Source Converter based High Voltage Direct Current) is a DC transmission technology that uses fully controlled devices such as IGBTs (Insulated Gate Bipolar Transistors) as core power devices. Compared with conventional DC transmission (LCC-HVDC, Line Commutated Converter based High Voltage Direct Current), it has advantages in reactive power compensation, no need for supporting power sources, no commutation failure, and flexible power control. Future applications such as distributed energy grid connection, back-to-back AC grid projects, islanded system power supply, and deep-sea wind power transmission will primarily utilize flexible DC transmission as the external transmission route. However, limited by the current-carrying capacity of IGBT devices, the maximum DC current of currently completed flexible DC projects both domestically and internationally is only 3kA. With the gradual advancement of energy development, the demand for ultra-high voltage, high-capacity flexible DC transmission and its core converter valve equipment is becoming increasingly urgent.

[0003] However, with the increase in single-module capacity, in addition to the improved current-carrying performance of IGBT devices, the increased capacitance of submodules leads to a significant increase in the magnitude of the shoot-through short-circuit current that may result from power device breakdown under extreme fault conditions. High voltage and high current may cause overvoltage breakdown of semiconductor devices and shell rupture, potentially damaging the power module and adjacent modules, resulting in the inability to reliably bypass the flexible DC converter valve module in case of failure. Therefore, it is crucial to verify the protection performance of the flexible DC converter valve submodule under extreme fault conditions through experiments. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a destructive testing method, apparatus, equipment and medium for flexible DC converter valves, so as to improve the rationality and accuracy of the protection performance testing of flexible DC converter valve sub-modules and improve the reliability of flexible DC power transmission.

[0005] To address the above technical problems, embodiments of the present invention provide a destructive testing method for a flexible DC converter valve, comprising:

[0006] Based on the long-term current-carrying capability of the IGBT devices in the flexible DC converter valve submodule, an IGBT test sample submodule is constructed; wherein, the IGBT test sample submodule includes a test sample submodule with IGBT having long-term current-carrying capability and a test sample submodule with IGBT not having long-term current-carrying capability.

[0007] Destructive tests involving the upper and lower IGBTs were conducted on the test sub-modules with IGBTs having long-term current carrying capacity and the test sub-modules without IGBTs having long-term current carrying capacity.

[0008] A destructive test was conducted on the test submodule of the IGBT with long-term current carrying capacity, involving the destructive effect of a bypass switch mis-closing.

[0009] Bypass switch failure destructive test was performed on the test sub-modules of IGBT with long-term current carrying capacity and the test sub-modules of IGBT without long-term current carrying capacity respectively;

[0010] The explosion-proof performance of the flexible DC converter valve is judged based on the test phenomena observed in the above and below IGBT direct-through destructive test, the bypass switch mis-closing destructive test, and the bypass switch failure to operate destructive test, and the test results are obtained.

[0011] As an improvement to the above scheme, the above-mentioned IGBT shoot-through destructive test, bypass switch mis-closing destructive test, and bypass switch failure to operate destructive test all include overall assessment-level destructive test and device assessment-level destructive test.

[0012] Preferably, the overall assessment-level destructive test is conducted using a complete IGBT test module with long-term current carrying capacity / an IGBT test module without long-term current carrying capacity;

[0013] The device evaluation-level destructive test uses an insulating pad, metal block, or a failed IGBT device to replace the IGBT device in the test sub-module with long-term current carrying capacity or the test sub-module without long-term current carrying capacity to construct an equivalent test circuit for testing.

[0014] As an improvement to the above scheme, a 168-hour long-term current-carrying test is conducted on the test sub-modules with and without IGBT long-term current-carrying capability, respectively, based on the maximum operating current values ​​of the test sub-modules with and without IGBT long-term current-carrying capability.

[0015] Preferably, the test submodule with long-term current carrying capacity of the IGBT includes an upper IGBT device, a lower IGBT device, an upper anti-parallel diode, a lower anti-parallel diode, a DC capacitor, a resistor, and a bypass switch; the upper anti-parallel diode is connected in parallel to the upper IGBT device, the lower anti-parallel diode is connected in parallel to the lower IGBT device, one end of the upper IGBT device is connected to one end of the DC capacitor, the other end of the upper IGBT device is connected to one end of the lower IGBT device, the other end of the lower IGBT device is connected to the other end of the DC capacitor, the resistor is connected in parallel to the DC capacitor, one end of the bypass switch is connected to one end of the lower IGBT device, and the other end of the bypass switch is connected to the other end of the lower IGBT device; wherein, the failure characteristic of the upper and lower IGBT devices is short circuit;

[0016] The test submodule for IGBTs lacking long-term current carrying capacity includes an upper IGBT device, a lower IGBT device, a transition thyristor connected in parallel with the lower IGBT device, an upper IGBT anti-parallel diode, a lower IGBT anti-parallel diode, a DC capacitor, a resistor, and a bypass switch. The upper IGBT anti-parallel diode is connected in parallel to the upper IGBT device, and the lower IGBT anti-parallel diode is connected in parallel to the lower IGBT device. One end of the upper IGBT device is connected to one end of the DC capacitor, and the other end of the upper IGBT device is connected to one end of the lower IGBT device. The other end of the lower IGBT device is connected to the other end of the DC capacitor. The transition thyristor is connected in parallel to the lower IGBT device. The resistor is connected in parallel to the DC capacitor. One end of the bypass switch is connected to one end of the lower IGBT device, and the other end of the bypass switch is connected to the other end of the lower IGBT device. The failure characteristic of the upper and lower IGBT devices is an open circuit.

[0017] Preferably, the step of performing a direct-through destructive test on the upper and lower IGBTs of the test sub-modules with and without long-term current carrying capacity of the IGBTs includes:

[0018] The desaturation protection function of the test sub-module with long-term current carrying capacity of the IGBT and the test sub-module without long-term current carrying capacity of the IGBT are respectively disabled, and the IGBT is charged to the first predetermined test voltage.

[0019] By actively triggering the conduction of the upper and lower IGBT devices in the test sub-modules with long-term current carrying capacity and the test sub-modules without long-term current carrying capacity, a direct short-circuit loop between the upper and lower IGBTs is formed.

[0020] Wherein, the first predetermined test voltage is the overvoltage protection setting value for the test sub-module of the IGBT with long-term current carrying capacity and the test sub-module of the IGBT without long-term current carrying capacity.

[0021] Preferably, a destructive test of bypass switch mis-closing is performed on the test submodule of the IGBT with long-term current carrying capacity, including:

[0022] Increase the operating voltage of the test submodule with long-term current carrying capacity of the IGBT. When the capacitor voltage of the DC capacitor in the test submodule with long-term current carrying capacity of the IGBT reaches the second predetermined test voltage, a command is issued to close the bypass switch to form a short circuit circuit.

[0023] Wherein, the second predetermined test voltage is the lockout overvoltage protection setting value of the test sample submodule of the IGBT with long-term current carrying capacity.

[0024] Preferably, a destructive test of bypass switch failure is performed on the test submodule of the IGBT with long-term current carrying capacity, including:

[0025] The bypass switch in the test submodule of the IGBT with long-term current carrying capacity is shielded or removed to disable the bypass switch.

[0026] Increase the charging voltage of the test sub-module with long-term current carrying capacity of the IGBT. When the capacitor voltage of the DC capacitor in the test sub-module with long-term current carrying capacity of the IGBT reaches the third predetermined test voltage, the upper IGBT device and the lower IGBT device will be over-voltage broken down and present a short circuit state.

[0027] The third predetermined test voltage is the upper limit of the active breakdown voltage of the upper and lower IGBT devices of the test submodule with long-term current carrying capacity.

[0028] Preferably, a destructive test of bypass switch failure is performed on the test submodule of the IGBT that does not have long-term current carrying capacity, including:

[0029] The bypass switch closing circuit of the test submodule of the IGBT that does not have long-term current carrying capacity is disconnected to simulate switch failure.

[0030] Increase the charging voltage of the test sub-module where the IGBT does not have long-term current carrying capacity. When the capacitance voltage of the DC capacitor in the test sub-module where the IGBT has long-term current carrying capacity reaches the fourth predetermined test voltage, the switching thyristor, the upper IGBT device, or the upper anti-parallel diode will be over-voltage broken down and present a short circuit state.

[0031] The fourth predetermined test voltage is the upper limit of the breakdown voltage of the turnaround thyristor of the test submodule of the IGBT that does not have long-term current carrying capacity.

[0032] To address the above technical problems, embodiments of the present invention also provide a destructive testing device for a flexible DC converter valve, comprising:

[0033] The IGBT test sample submodule construction module is used to construct an IGBT test sample submodule based on the long-term current carrying capacity of the IGBT devices in the flexible DC converter valve submodule; wherein, the IGBT test sample submodule includes test sample submodules with IGBT having long-term current carrying capacity and test sample submodules without IGBT having long-term current carrying capacity.

[0034] The upper and lower IGBT shoot-through destructive test module is used to perform upper and lower IGBT shoot-through destructive tests on the test sub-modules of the IGBT with long-term current carrying capability and the test sub-modules of the IGBT without long-term current carrying capability, respectively.

[0035] The bypass switch mis-closing destructive test module is used to conduct a bypass switch mis-closing destructive test on the test sub-module of the IGBT with long-term current carrying capacity.

[0036] The bypass switch failure destructive test module is used to conduct bypass switch failure destructive tests on the IGBT test sub-modules with long-term current carrying capacity and the IGBT test sub-modules without long-term current carrying capacity, respectively.

[0037] The test judgment module is used to judge the explosion-proof performance of the flexible DC converter valve based on the test phenomena of the upper and lower IGBT direct-through destructive test, the bypass switch mis-closing destructive test, and the bypass switch failure to operate destructive test, and obtain the test results.

[0038] To address the above technical problems, embodiments of the present invention provide a terminal device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the destructive testing method for flexible DC converter valves as described above.

[0039] To address the above technical problems, this invention provides a computer-readable storage medium, which includes a stored computer program. When the computer program is executed, it controls the device containing the computer-readable storage medium to perform the destructive testing method for the flexible DC converter valve as described above.

[0040] Compared with the prior art, the present invention provides a destructive testing method, apparatus, equipment, and medium for a flexible DC converter valve. First, based on the long-term current-carrying capability of the IGBT devices in the flexible DC converter valve sub-module, an IGBT test sub-module is constructed. This IGBT test sub-module includes test sub-modules with IGBTs possessing long-term current-carrying capability and test sub-modules without IGBTs possessing long-term current-carrying capability. Second, destructive tests are performed on the test sub-modules with and without IGBTs, including a direct-through destructive test of the upper and lower IGBTs, a bypass switch mis-closing destructive test, and a bypass switch failure destructive test. Finally, the explosion-proof performance of the flexible DC converter valve is judged based on the test phenomena observed in the above three types of tests, and the test results are obtained. This invention divides the IGBT test module into test modules with IGBTs having long-term current-carrying capability and test modules without IGBTs having long-term current-carrying capability. It also conducts three types of tests: destructive test of upper and lower IGBT direct connection, destructive test of bypass switch mis-closing, and destructive test of bypass switch failure to operate. This can simulate the actual working environment of flexible DC converter valves, better meet the needs of destructive testing of flexible DC converter valves, improve the accuracy of test results, and detect the performance reliability of flexible DC converter valves. Attached Figure Description

[0041] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a flowchart of a destructive testing method for a flexible DC converter valve provided in an embodiment of the present invention;

[0043] Figure 2 This is the electrical schematic diagram of the IGBT sample submodule with long-term current carrying capacity provided in this embodiment of the invention;

[0044] Figure 3 This is the electrical schematic diagram of the test sample submodule of the IGBT that does not have long-term current carrying capacity provided in the embodiment of the present invention;

[0045] Figure 4 This is another flowchart of a destructive testing method for a flexible DC converter valve provided in an embodiment of the present invention;

[0046] Figure 5This is a schematic diagram of the overall assessment stage upper and lower IGBT shoot-through destructive test provided in an embodiment of the present invention;

[0047] Figure 6 This is a schematic diagram of the device evaluation stage upper and lower IGBT shoot-through destructive test provided in the embodiment of the present invention;

[0048] Figure 7 This is a schematic diagram of the destructive test principle for the bypass switch mis-closing in the overall assessment provided by an embodiment of the present invention;

[0049] Figure 8 This is a schematic diagram of the destructive test principle for the bypass switch mis-closing in the device-level evaluation provided in this embodiment of the invention;

[0050] Figure 9 This is a schematic diagram of the overall assessment level bypass switch failure destructive test of the IGBT test sample submodule with long-term current carrying capacity provided in the embodiment of the present invention;

[0051] Figure 10 This is a schematic diagram of the device evaluation-level bypass switch failure destructive test of the IGBT test sample submodule with long-term current carrying capacity provided in the embodiment of the present invention;

[0052] Figure 11 This is a schematic diagram of the destructive test of the bypass switch failure of the test sample submodule of the IGBT that does not have long-term current carrying capacity, provided in the embodiment of the present invention.

[0053] Figure 12 This is a schematic diagram of a device evaluation-level bypass switch failure destructive test for a test module of an IGBT that does not have long-term current carrying capacity, provided in an embodiment of the present invention.

[0054] Figure 13 This is a structural block diagram of a destructive testing device for a flexible DC converter valve provided in an embodiment of the present invention;

[0055] Figure 14 This is a structural block diagram of a terminal device provided in an embodiment of the present invention. Detailed Implementation

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] See Figure 1The present invention provides a flowchart of a destructive testing method for a flexible DC converter valve, the destructive testing method for the flexible DC converter valve including steps S1 to S5:

[0058] S1. Based on the long-term current carrying capacity of the IGBT devices in the flexible DC converter valve submodule, construct an IGBT test sample submodule; wherein, the IGBT test sample submodule includes a test sample submodule with IGBT having long-term current carrying capacity and a test sample submodule with IGBT not having long-term current carrying capacity.

[0059] Specifically, the test sub-module with long-term current-carrying capability includes an upper IGBT device, a lower IGBT device, an upper anti-parallel diode, a lower anti-parallel diode, a DC capacitor, a resistor, and a bypass switch. The upper anti-parallel diode is connected in parallel to the upper IGBT device, and the lower anti-parallel diode is connected in parallel to the lower IGBT device. One end of the upper IGBT device is connected to one end of the DC capacitor, and the other end of the upper IGBT device is connected to one end of the lower IGBT device. The other end of the lower IGBT device is connected to the other end of the DC capacitor. The resistor is connected in parallel to the DC capacitor. One end of the bypass switch is connected to one end of the lower IGBT device, and the other end of the bypass switch is connected to the other end of the lower IGBT device. The failure characteristic of the upper and lower IGBT devices is short circuit.

[0060] The test submodule for IGBTs lacking long-term current carrying capacity includes an upper IGBT device, a lower IGBT device, a transition thyristor connected in parallel with the lower IGBT device, an upper IGBT anti-parallel diode, a lower IGBT anti-parallel diode, a DC capacitor, a resistor, and a bypass switch. The upper IGBT anti-parallel diode is connected in parallel to the upper IGBT device, and the lower IGBT anti-parallel diode is connected in parallel to the lower IGBT device. One end of the upper IGBT device is connected to one end of the DC capacitor, and the other end of the upper IGBT device is connected to one end of the lower IGBT device. The other end of the lower IGBT device is connected to the other end of the DC capacitor. The transition thyristor is connected in parallel to the lower IGBT device. The resistor is connected in parallel to the DC capacitor. One end of the bypass switch is connected to one end of the lower IGBT device, and the other end of the bypass switch is connected to the other end of the lower IGBT device. The failure characteristic of the upper and lower IGBT devices is an open circuit.

[0061] For example, see Figure 2 , Figure 2 This is an electrical schematic diagram of the IGBT test module with long-term current carrying capacity provided in an embodiment of the present invention, such as... Figure 2 As shown, VT1 and VT2 are the upper and lower IGBT devices, respectively; D1 and D2 are the upper and lower IGBT anti-parallel diodes, respectively; C is the DC capacitor for the flexible DC converter valve submodule; R is the voltage equalizing resistor; and K is the bypass switch. The upper IGBT anti-parallel diode D1 is connected in parallel to the upper IGBT device VT1, and the lower IGBT anti-parallel diode D2 is connected in parallel to the lower IGBT device VT2. One end of the upper IGBT device VT1 is connected to one end of the DC capacitor C, and the other end of the upper IGBT device VT1 is connected to one end of the lower IGBT device VT2. The other end of the lower IGBT device VT2 is connected to the other end of the DC capacitor C. The resistor R is connected in parallel to the DC capacitor C. One end of the bypass switch K is connected to one end of the lower IGBT device VT2, and the other end of the bypass switch K is connected to the other end of the lower IGBT device VT2.

[0062] See Figure 3 , Figure 3 This is an electrical schematic diagram of a test submodule of IGBT without long-term current carrying capacity provided in an embodiment of the present invention. Compared with the test submodule of IGBT with long-term current carrying capacity, the failure characteristic of the multiple configured power devices IGBT is open circuit, and the circuit is equipped with a transition thyristor T connected in parallel with the lower IGBT.

[0063] S2. Perform a direct-through destructive test on the upper and lower IGBTs on the test sub-modules with IGBTs having long-term current carrying capacity and the test sub-modules without IGBTs having long-term current carrying capacity.

[0064] In one embodiment, the step of performing a direct-through destructive test on the upper and lower IGBTs of a test submodule with IGBTs possessing long-term current-carrying capability and a test submodule without IGBTs possessing long-term current-carrying capability includes:

[0065] The desaturation protection function of the test sub-module with long-term current carrying capacity of the IGBT and the test sub-module without long-term current carrying capacity of the IGBT are respectively disabled, and the IGBT is charged to the first predetermined test voltage.

[0066] By actively triggering the conduction of the upper and lower IGBT devices in the test sub-modules with long-term current carrying capacity and the test sub-modules without long-term current carrying capacity, a direct short-circuit loop between the upper and lower IGBTs is formed.

[0067] Wherein, the first predetermined test voltage is the overvoltage protection setting value for the test sub-module of the IGBT with long-term current carrying capacity and the test sub-module of the IGBT without long-term current carrying capacity.

[0068] Preferably, the IGBT shoot-through destructive test includes an overall assessment-level destructive test and a device assessment-level destructive test.

[0069] In one embodiment, the IGBT test submodule undergoes an overall evaluation-level IGBT shoot-through destructive test, including:

[0070] The IGBT test module is desaturated and driven by the protection shield and then charged to a predetermined voltage.

[0071] Actively trigger the lower IGBT device to conduct, and establish current in the lower IGBT device through the inductor circuit;

[0072] The upper IGBT device is triggered after a predetermined time. When both the upper and lower IGBT devices are turned on simultaneously, a shoot-through short-circuit loop is formed.

[0073] In one embodiment, the IGBT test module is subjected to a device evaluation-level shoot-through destructive test on the upper and lower IGBTs, including:

[0074] A metal block is used to replace the upper IGBT device in the IGBT test sample submodule to construct a first equivalent test circuit.

[0075] The capacitor in the first equivalent test circuit is charged to reach the preset voltage;

[0076] Actively triggering the conduction of the lower IGBT device, the upper metal block and the lower IGBT device form a direct short-circuit loop.

[0077] It should be noted that, since the direct-through short-circuit circuits of the upper and lower tubes require testing of the IGBT test sub-modules with long-term current carrying capacity and the IGBT test sub-modules without long-term current carrying capacity respectively, the term "IGBT test sub-module" in the above context includes both the test sub-modules with long-term current carrying capacity and the test sub-modules without long-term current carrying capacity, for the purpose of simplification.

[0078] S3. Conduct a destructive test on the bypass switch mis-closing of the test sub-module of the IGBT with long-term current carrying capacity.

[0079] In one embodiment, a destructive test of bypass switch mis-closing is performed on the test submodule of the IGBT with long-term current carrying capacity, including:

[0080] Increase the operating voltage of the test submodule with long-term current carrying capacity of the IGBT. When the capacitor voltage of the DC capacitor in the test submodule with long-term current carrying capacity of the IGBT reaches the second predetermined test voltage, close the bypass switch by issuing a command to form a short circuit circuit.

[0081] Wherein, the second predetermined test voltage is the lockout overvoltage protection setting value of the test sample submodule of the IGBT with long-term current carrying capacity.

[0082] Preferably, the destructive test for accidental closing of the bypass switch includes an overall assessment-level destructive test and a device assessment-level destructive test.

[0083] In one embodiment, a test submodule of the IGBT with long-term current carrying capacity is used to conduct a destructive test on the overall evaluation-level bypass switch mis-closing, including:

[0084] Increase the operating voltage of the test submodule of the IGBT with long-term current carrying capacity;

[0085] When the charging voltage of the test submodule with long-term current carrying capacity of the IGBT is not lower than the blocking voltage, a command is issued to close the bypass switch when the upper IGBT device is in the conducting state, and the upper IGBT device and the bypass switch form a short circuit loop.

[0086] In one embodiment, a test submodule of the IGBT with long-term current carrying capacity is used to conduct a destructive test on the device evaluation-grade bypass switch mis-closing, including:

[0087] A second equivalent test circuit is constructed by replacing the upper IGBT device in the test sample submodule with the IGBT having long-term current carrying capacity with a failed IGBT device or a metal block.

[0088] Increase the operating voltage of the second equivalent test circuit;

[0089] When the charging voltage of the second equivalent test circuit is not lower than the blocking voltage, a command is issued to close the bypass switch when the upper IGBT device is in the on state. The upper IGBT device or metal block that fails forms a short circuit with the bypass switch.

[0090] S4. Perform a destructive test on the bypass switch failure of the test sub-module with long-term current carrying capacity and the test sub-module without long-term current carrying capacity of the IGBT respectively.

[0091] In one embodiment, a destructive test of bypass switch failure is performed on the test submodule of the IGBT with long-term current carrying capacity, including:

[0092] The bypass switch in the test submodule of the IGBT with long-term current carrying capacity is shielded or removed to disable the bypass switch.

[0093] Increase the charging voltage of the test sub-module with long-term current carrying capacity of the IGBT. When the capacitor voltage of the DC capacitor in the test sub-module with long-term current carrying capacity of the IGBT reaches the third predetermined test voltage, the upper IGBT device and the lower IGBT device will be over-voltage broken down and present a short circuit state.

[0094] The third predetermined test voltage is the upper limit of the active breakdown voltage of the upper and lower IGBT devices of the test submodule with long-term current carrying capacity.

[0095] In one embodiment, a destructive test of bypass switch failure is performed on the test submodule of the IGBT that does not have long-term current carrying capacity, including:

[0096] The bypass switch closing circuit of the test submodule of the IGBT that does not have long-term current carrying capacity is disconnected to simulate switch failure.

[0097] Increase the charging voltage of the test sub-module where the IGBT does not have long-term current carrying capacity. When the capacitance voltage of the DC capacitor in the test sub-module where the IGBT has long-term current carrying capacity reaches the fourth predetermined test voltage, the switching thyristor, the upper IGBT device, or the upper anti-parallel diode will be over-voltage broken down and present a short circuit state.

[0098] The fourth predetermined test voltage is the upper limit of the breakdown voltage of the turnaround thyristor of the test submodule of the IGBT that does not have long-term current carrying capacity.

[0099] Preferably, the destructive test for the bypass switch failure includes an overall assessment-level destructive test and a device assessment-level destructive test.

[0100] Specifically, the bypass switch failure destructive test is performed using the IGBT test specimen submodule, including:

[0101] An overall assessment-level destructive test was conducted on the test sub-module of the IGBT with long-term current carrying capacity, which was subjected to a bypass switch failure test.

[0102] A device evaluation-level bypass switch failure destructive test was conducted on the test sub-module of the IGBT with long-term current carrying capacity.

[0103] An overall assessment-level destructive test was conducted on the test sub-module of the IGBT that did not have long-term current carrying capacity, to determine whether the bypass switch would fail to operate.

[0104] For the test submodule of the IGBT that does not have long-term current carrying capacity, a device evaluation-level bypass switch failure destructive test was conducted.

[0105] In one embodiment, the destructive test of the bypass switch failure of the test submodule of the IGBT with long-term current carrying capacity includes:

[0106] Shield or remove the bypass switch of the test submodule of the IGBT with long-term current carrying capacity to disable the bypass switch;

[0107] The power module is continuously pressurized so that the capacitor voltage of the test sub-module with long-term current carrying capacity of the IGBT is charged to a preset voltage until the upper and lower IGBT devices are over-voltaged and break down, resulting in a short circuit.

[0108] In one embodiment, the device evaluation-level bypass switch failure destructive test on the test submodule of the IGBT with long-term current carrying capability includes:

[0109] Shield or remove the bypass switch of the test submodule of the IGBT with long-term current carrying capacity to disable the bypass switch;

[0110] An insulating block is used to replace the upper IGBT device of the test submodule with long-term current carrying capacity to construct a third equivalent test circuit;

[0111] The power module is continuously pressurized to charge the capacitor voltage of the third equivalent test circuit to the preset voltage until the upper and lower IGBT devices break down due to overvoltage and exhibit a short circuit state.

[0112] In one embodiment, the destructive test of the bypass switch failure to operate on the test submodule of the IGBT that does not have long-term current carrying capacity includes:

[0113] The bypass switch closing circuit of the test submodule of the IGBT that does not have long-term current carrying capacity is disconnected to simulate switch failure.

[0114] The power module is continuously pressurized until the switching thyristor, the upper IGBT device, or the upper anti-parallel diode breaks down due to overvoltage, resulting in a short circuit.

[0115] In one embodiment, the destructive test of the bypass switch failure to operate on the test submodule of the IGBT that does not have long-term current carrying capacity includes:

[0116] Shield or remove the bypass switch of the test submodule of the IGBT that does not have long-term current carrying capacity, so that the bypass switch is ineffective.

[0117] An insulating block is used to replace the upper and lower IGBT devices in the test sample sub-module where the IGBT does not have long-term current carrying capacity, to construct a fourth equivalent test circuit;

[0118] The power module is continuously pressurized until the turnaround thyristor and the upper anti-parallel diode of the fourth equivalent test circuit break down due to overvoltage, resulting in a short circuit.

[0119] S5. Based on the experimental phenomena, the explosion-proof performance of the flexible DC converter valve is judged, and the experimental results are obtained.

[0120] Specifically, it is necessary to determine whether the test sub-module of IGBT with long-term current carrying capacity / test sub-module of IGBT without long-term current carrying capacity has exploded, whether there is water leakage in the cooling system after the explosion, whether there are objects splashing, and whether the internal busbar components of the IGBT test sub-module are deformed.

[0121] If so, the destructive test of the flexible DC converter valve is deemed unsuccessful.

[0122] As an improvement to the above scheme, the destructive testing method for the flexible DC converter valve, as described above, further includes:

[0123] Based on the maximum operating current values ​​of the test sub-modules with and without IGBT long-term current carrying capacity, a 168-hour long-term current carrying capacity test was conducted on the test sub-modules with and without IGBT long-term current carrying capacity.

[0124] It is worth noting that in this embodiment of the invention, the IGBT shoot-through destructive test, the bypass switch mis-closing destructive test, and the bypass switch failure-to-operate destructive test all include overall assessment-level destructive tests and device assessment-level destructive tests. Specifically, the IGBT shoot-through destructive test simulates the extreme case of simultaneous conduction of the upper and lower IGBTs, verifying whether the system can operate normally or safely enter the protection state under such conditions; the bypass switch mis-closing destructive test simulates the extreme case of a bypass switch mis-closing, verifying whether the system can detect the mis-closing in a timely manner and take protective measures; the bypass switch failure-to-operate destructive test simulates the extreme case of a bypass switch failure to operate, verifying whether the system can detect the failure to operate in a timely manner and take protective measures. The overall assessment-level destructive test aims to verify the overall reliability of the flexible DC converter valve under extreme conditions, while the device assessment-level destructive test aims to verify the reliability of key components in the system. By conducting overall assessment-level and device assessment-level destructive tests, the reliability of the flexible DC converter valve and key components can be comprehensively evaluated, ensuring that the flexible DC converter valve can operate safely and reliably in practical applications.

[0125] It should be noted that the overall assessment-level destructive test is conducted on a complete IGBT test module; the device assessment-level destructive test uses insulating pads, metal blocks, or failed IGBT devices to replace the IGBT devices in the IGBT test module, constructing an equivalent test circuit for testing. Specifically, the device assessment-level destructive test aims to assess the most stringent fault inrush current for various devices, using insulating pads, metal blocks, failed IGBT devices, etc., to design an equivalent test circuit.

[0126] To enable those skilled in the art to better understand the technical solution of the present invention, the test method provided by the present invention will be further explained below in conjunction with specific test implementation steps.

[0127] This invention addresses the issue of overvoltage in UHV flexible DC converter submodules caused by faults within converter stations, leading to large-scale bypassing of submodules. It proposes a destructive testing method for flexible DC converter valves, specifically for UHV flexible DC converter valves, to verify the explosion-proof performance of the converter valve submodules. A detailed description of the test scheme follows.

[0128] Reference Figure 4 This is a flowchart of a destructive test for a flexible DC converter valve provided in an embodiment of the present invention. In specific implementation, the flexible DC converter valve is of the 5kA class. During the test, the DC capacitor discharges through a short-circuit loop, and the stored energy is released instantaneously through the power device and connecting busbar. This may cause the power device to rupture due to electrothermal stress, objects to splash, the busbar to break due to electrodynamic detachment, water pipes to leak due to airflow and splash impact, or the power device to fail and lose its normal current-carrying capacity after an explosion. After the test, the explosion-proof performance of the converter valve submodule can be evaluated in detail according to the above standards. If any of the above situations exist, the test is deemed unsuccessful. Figure 4 As shown, the test method includes three destructive tests: upper and lower IGBT shoot-through, bypass switch mis-closing, and bypass switch failure to operate.

[0129] 1. Destructive test of the upper and lower IGBTs through-through:

[0130] 1) Conduct a destructive test on the upper and lower IGBTs for overall assessment. The test schematic is shown below. Figure 5 As shown:

[0131] Step 1: Shield the desaturation drive protection of the test submodule and charge the test submodule to the predetermined voltage. Actively trigger the conduction of the lower IGBT-VT2 and establish current in the lower IGBT-VT2 through the inductor circuit.

[0132] Step 2: Then the upper IGBT is triggered, and both the upper and lower IGBTs are turned on at the same time, forming a direct short circuit loop. At this time, the capacitor C discharges, and the large short circuit current passes through the upper IGBT-VT1 and the lower IGBT-VT2 in sequence. The release of short circuit energy may cause the power devices of the upper and lower IGBTs to explode.

[0133] Step 3: After the test, a detailed analysis is conducted on the results of the shoot-through destructive test of the upper and lower IGBTs based on whether the module exploded, whether there was water leakage in the cooling system after the explosion, whether there was any splashing of objects, the deformation of components such as the internal busbar of the test sub-module, and the 168-hour current-carrying test of the failed power device IGBT-VT2 of the test sub-module with long-term current carrying capacity under the maximum operating current of the module.

[0134] 2) Conduct a device-level performance test involving the shoot-through destructive operation of the upper and lower IGBTs. The test schematic is shown below. Figure 6 As shown:

[0135] Step 1: Replace the upper IGBT device in the test sample submodule with a metal block;

[0136] Step 2: Charge the submodule capacitor C with a DC power supply until it reaches the preset voltage;

[0137] Step 3: By actively triggering the conduction of the lower IGBT-VT2 device, the upper metal block and the lower IGBT-VT2 form a direct short circuit loop. At this time, the capacitor C discharges, and the large short circuit current passes through the upper metal block and the lower IGBT-VT2 in sequence. The release of short circuit energy may cause the IGBT-VT2 to explode.

[0138] Step 4: After the test, a detailed analysis is conducted on the results of the direct-through destructive test of the upper and lower tubes based on whether the module exploded, whether there was water leakage in the cooling system after the explosion, whether there was any splashing of objects, the deformation of components such as the busbar inside the submodule, and the 168-hour current-carrying test of the failed power device IGBT-VT2 under the maximum operating current of the module.

[0139] 2. Destructive test for accidental closing of bypass switch:

[0140] 1) Conduct a destructive test on the bypass switch for overall assessment due to mis-closing. The test schematic is as follows: Figure 7 As shown:

[0141] Step 1: Configure a bypass switch K in the test submodule to increase the operating voltage of a single submodule to the maximum continuous operating load condition;

[0142] Step 2: When the charging voltage of the test sub-module is not lower than the blocking voltage of the sub-module, with the upper IGBT-VT1 of the converter valve in the on state, a command is issued to close the sub-module bypass switch K. The upper IGBT-VT1 and the bypass switch K form a short circuit circuit. At this time, the capacitor C discharges, and the large short circuit current passes through the upper IGBT-VT1 and the bypass switch K in sequence. The release of short circuit energy may cause the upper IGBT-VT1 to explode.

[0143] Step 3: After the test, a detailed analysis is conducted on the results of the destructive test of the bypass switch mis-closing based on whether the module exploded, whether there was water leakage in the cooling system after the explosion, whether there was any splashing of objects, the deformation of components such as the busbar inside the sub-module, and the 168-hour current-carrying test of the failed power device IGBT-VT1 under the maximum operating current of the module.

[0144] 2) Conduct a destructive test on the bypass switch for device-level evaluation. The test schematic is shown below. Figure 8 As shown:

[0145] Step 1: Replace the upper IGBT-VT1 device in the test sample submodule with a failed IGBT or a metal block;

[0146] Step 2: Configure the bypass switch K on the test submodule to increase the operating voltage of a single submodule to the maximum continuous operating load condition;

[0147] Step 3: When the charging voltage of the test sub-module is not lower than the blocking voltage of the sub-module, with the upper IGBT-VT1 of the converter valve in the on state, a command is issued to close the sub-module bypass switch K. The failed upper IGBT and the bypass switch K form a short circuit circuit. At this time, the capacitor C discharges, and the large short circuit current passes through the failed IGBT and the bypass switch K in sequence. The release of short circuit energy may cause the failed IGBT to explode.

[0148] Step 4: After the test, a detailed analysis is conducted on the results of the destructive test of the bypass switch mis-closing based on whether the module exploded, whether there was water leakage in the cooling system after the explosion, whether there was any splashing of objects, the deformation of components such as the busbar inside the sub-module, and the 168-hour current-carrying test of the failed power device IGBT under the maximum operating current of the module.

[0149] 3. Destructive test for bypass switch failure to operate:

[0150] 1) Conduct an overall bypass switch failure test on the test submodule with IGBTs possessing long-term failure current-carrying capability, i.e., without a transition thyristor. The test schematic is as follows: Figure 9 As shown:

[0151] Step 1: Shield or remove the bypass switch K to disable it;

[0152] Step 2: Continuously apply voltage to the power module to charge the sub-module capacitor voltage to the preset voltage until the upper and lower power devices are over-voltaged and break down, resulting in a short circuit. At this time, capacitor C discharges, and the large short-circuit current passes through the broken IGBTs or anti-parallel diodes in sequence. The release of short-circuit energy may cause the failed power devices to explode.

[0153] Step 3: After the test, a detailed analysis is conducted on the results of the destructive test of the bypass switch mis-closing based on whether the module exploded, whether there was water leakage in the cooling system after the explosion, whether there were objects splashing, the deformation of components such as the busbar inside the sub-module, and the 168-hour current-carrying test of the failed power device IGBT under the maximum operating current of the module.

[0154] 2) Conduct a device-level bypass switch failure test on the test submodule with IGBTs possessing long-term failure current-carrying capability, i.e., without a transition thyristor. The test schematic is shown below. Figure 10 As shown:

[0155] Step 1: Shield or remove the bypass switch K to disable the bypass switch K;

[0156] Step 2: Replace the upper IGBT-VT1 device of the test sample submodule with an insulating block;

[0157] Step 3: Continuously apply voltage to the power module to charge the sub-module capacitor voltage to the preset voltage until the upper and lower power devices are over-voltaged and break down, presenting a short circuit state. At this time, the capacitor C discharges, and the large short circuit current passes through the broken down anti-parallel diode D1 of the upper tube and the broken down IGBT-VT1 power device in sequence. The release of short circuit energy may cause the failed power device to explode.

[0158] Step 4: After the test, a detailed analysis is conducted on the results of the destructive test of the bypass switch mis-closing based on whether the module exploded, whether there was water leakage in the cooling system after the explosion, whether there was any splashing of objects, the deformation of components such as the busbar inside the submodule, and the 168-hour current-carrying test of the failed power device under the maximum operating current of the module.

[0159] 3) For IGBTs that do not possess long-term failure current carrying capacity, i.e., test submodules equipped with transition thyristors, conduct an overall bypass switch failure test. The test schematic is shown below. Figure 11 As shown:

[0160] Step 1: Disconnect the bypass switch K closing circuit of the power module in the test sample sub-module to simulate switch failure;

[0161] Step 2: Continuously apply pressure to the power module until the turnaround thyristor T, upper IGBT-VT1 or anti-parallel diode D1 of the test sub-module are over-voltage broken down and short-circuited. At this time, capacitor C discharges and the large short-circuit current passes through the broken-down power device and the turnaround thyristor T in sequence. The release of short-circuit energy may cause the failed power device to explode.

[0162] Step 3: After the test, a detailed analysis is conducted on the results of the destructive test of the bypass switch mis-closing based on whether the module exploded, whether there was water leakage in the cooling system after the explosion, whether there was any splashing of objects, the deformation of components such as the busbar inside the submodule, and the 168-hour current-carrying test of the failed power device under the maximum operating current of the module.

[0163] 4) For IGBTs that lack long-term failure current carrying capacity (i.e., those equipped with a transition thyristor), a device-level bypass switch failure test is conducted. The test schematic is shown below. Figure 12 As shown:

[0164] Step 1: Shield or remove the bypass switch K to disable it;

[0165] Step 2: Replace the upper and lower IGBT devices in the test sample sub-module with insulating blocks;

[0166] Step 3: Continuously apply pressure to the power module until the test module's transition thyristor T and upper anti-parallel diode D1 break down due to overvoltage, resulting in a short circuit. At this time, capacitor C discharges, and the large short-circuit current passes through the broken-down upper anti-parallel diode D1 and transition thyristor T in sequence. The release of short-circuit energy may cause the failed power device to explode.

[0167] Step 4: After the test, a detailed analysis is conducted on the results of the destructive test of the bypass switch mis-closing based on whether the module exploded, whether there was water leakage in the cooling system after the explosion, whether there was any splashing of objects, the deformation of components such as the busbar inside the submodule, and the 168-hour current-carrying test of the failed power device under the maximum operating current of the module.

[0168] In summary, the destructive testing method for a flexible DC converter valve provided by this invention firstly categorizes module destructive tests into three types based on the actual operating conditions of the flexible DC converter valve: upper and lower IGBT shoot-through test, bypass switch mis-closing test, and bypass switch failure test. Secondly, for sub-modules where the IGBTs lack long-term current carrying capacity and are equipped with a transition thyristor, bypass failure and upper and lower IGBT shoot-through tests are conducted. Then, for sub-modules where the IGBTs possess long-term current carrying capacity but are not equipped with a transition thyristor, bypass mis-closing, bypass failure, and upper and lower IGBT shoot-through tests are conducted. Finally, considering more stringent test conditions, all tests are divided into overall assessment-level destructive tests using a complete module and device assessment-level destructive tests using an equivalent test circuit. Based on simulating the actual operating conditions of the converter valve, an equivalent test circuit is constructed using insulating pads, metal blocks, etc., avoiding the current sharing phenomenon between the IGBTs and anti-parallel diodes. This allows for the assessment of the device's explosion-proof performance under the most stringent conditions, improving the effectiveness of the test conclusions and possessing industrial application value.

[0169] Based on the above method embodiments, the present invention provides corresponding apparatus embodiments.

[0170] See Figure 13 This is a structural block diagram of a destructive testing device for a flexible DC converter valve provided in an embodiment of the present invention. The destructive testing device for the flexible DC converter valve includes:

[0171] IGBT test sample submodule construction module 21 is used to construct an IGBT test sample submodule based on the long-term current carrying capacity of the IGBT devices in the flexible DC converter valve submodule; wherein, the IGBT test sample submodule includes a test sample submodule with IGBT having long-term current carrying capacity and a test sample submodule without IGBT having long-term current carrying capacity.

[0172] The upper and lower IGBT direct-through destructive test module 22 is used to perform upper and lower IGBT direct-through destructive tests on the test sub-modules of the IGBT with long-term current carrying capacity and the test sub-modules of the IGBT without long-term current carrying capacity, respectively.

[0173] The bypass switch mis-closing destructive test module 23 is used to conduct a bypass switch mis-closing destructive test on the test sub-module of the IGBT with long-term current carrying capacity.

[0174] The bypass switch failure destructive test module 24 is used to perform bypass switch failure destructive tests on the test sub-modules of the IGBT with long-term current carrying capacity and the test sub-modules of the IGBT without long-term current carrying capacity, respectively.

[0175] The test judgment module 25 is used to judge the explosion-proof performance of the flexible DC converter valve based on the test phenomena of the upper and lower IGBT direct-through destructive test, the bypass switch mis-closing destructive test, and the bypass switch failure to operate destructive test, and to obtain the test results.

[0176] As an improvement to the above solution, the destructive testing device for the flexible DC converter valve further includes a long-term current-carrying test module, which is used to conduct a 168-hour long-term current-carrying test on the test sub-modules with and without long-term current-carrying capability of the IGBT based on the maximum operating current values ​​of the test sub-modules with and without long-term current-carrying capability of the IGBT.

[0177] It should be noted that the destructive testing device for a flexible DC converter valve provided in this embodiment of the invention is used to perform all the process steps of the destructive testing method for a flexible DC converter valve in the above embodiment. The working principles and beneficial effects of the two are one-to-one, so they will not be described again.

[0178] This invention also provides a terminal device, such as... Figure 14 The diagram shown is a structural block diagram of a preferred embodiment of a terminal device provided by the present invention. The terminal device includes a processor 31, a memory 32, and a computer program stored in the memory 32 and configured to be executed by the processor 31. When the processor 31 executes the computer program, it implements the destructive testing method for flexible DC converter valves as described in any of the above embodiments.

[0179] In addition, embodiments of the present invention also provide a computer-readable storage medium, the computer-readable storage medium including a stored computer program, wherein, when the computer program is executed, it controls the device where the computer-readable storage medium is located to perform the destructive testing method for flexible DC converter valves as described in any of the above embodiments.

[0180] When the processor 31 executes the computer program, it implements the steps in the above-described embodiments of the destructive testing method for flexible DC converter valves, for example... Figure 1 All steps of the destructive testing method for the flexible DC converter valve shown. Alternatively, when the processor 31 executes the computer program, it implements the functions of each module in the aforementioned destructive testing device for the flexible DC converter valve, for example... Figure 13 The functions of each module in the destructive testing device for the flexible DC converter valve are shown.

[0181] Preferably, the computer program can be divided into one or more modules / units, which are stored in the memory 32 and executed by the processor 31 to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing specific functions, which describe the execution process of the computer program in the terminal device.

[0182] The processor 31 can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor, or the processor 31 can be any conventional processor. The processor 31 is the control center of the terminal device, connecting various parts of the terminal device through various interfaces and lines.

[0183] The memory 32 mainly includes a program storage area and a data storage area. The program storage area can store the operating system, applications required for at least one function, etc., and the data storage area can store related data, etc. In addition, the memory 32 can be a high-speed random access memory, or a non-volatile memory, such as a plug-in hard disk, a smart media card (SMC), a secure digital card (SD), and a flash card, etc., or the memory 32 can also be other volatile solid-state storage devices.

[0184] It should be noted that the aforementioned terminal devices may include, but are not limited to, processors and memory, as will be understood by those skilled in the art. Figure 14 The structural block diagram shown is merely a structural example of the terminal device described above and does not constitute a limitation on the structure of the terminal device. The terminal device may include more or fewer components than shown, or combine certain components, or use different components.

[0185] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method of destructive testing of a flexible DC converter valve, characterized in that, The method comprises the following steps: According to the long-term current-carrying capacity of IGBT devices in a flexible HVDC converter valve sub-module, an IGBT sample sub-module is constructed; wherein the IGBT sample sub-module comprises an IGBT sample sub-module with long-term current-carrying capacity and an IGBT sample sub-module without long-term current-carrying capacity; The IGBT sample sub-module with long-term current-carrying capacity and the IGBT sample sub-module without long-term current-carrying capacity are respectively subjected to up-down IGBT straight-through destructive test; The IGBT sample sub-module with long-term current-carrying capacity is subjected to bypass switch mis-connection destructive test; The IGBT sample sub-module with long-term current-carrying capacity and the IGBT sample sub-module without long-term current-carrying capacity are respectively subjected to bypass switch refusal destructive test; According to the test phenomena of the up-down IGBT straight-through destructive test, the bypass switch mis-connection destructive test and the bypass switch refusal destructive test, the explosion-proof performance of the flexible HVDC converter valve is judged, and a test result is obtained.

2. The flexible DC converter valve destructive testing method of claim 1, wherein, The up-down IGBT straight-through destructive test, the bypass switch mis-connection destructive test and the bypass switch refusal destructive test all comprise whole examination level destructive test and device examination level destructive test.

3. The flexible DC converter valve destructive testing method of claim 2, wherein, The whole examination level destructive test adopts a complete IGBT sample sub-module with long-term current-carrying capacity / IGBT sample sub-module without long-term current-carrying capacity for test; The device examination level destructive test adopts an insulating pad or a metal block or a failed IGBT device to replace the IGBT device in the IGBT sample sub-module with long-term current-carrying capacity / IGBT sample sub-module without long-term current-carrying capacity to construct an equivalent test loop for test.

4. The flexible DC converter valve destructive testing method of claim 1, wherein, The method further comprises the following steps: According to the maximum operating current values of the IGBT sample sub-module with long-term current-carrying capacity and the IGBT sample sub-module without long-term current-carrying capacity, the IGBT sample sub-module with long-term current-carrying capacity and the IGBT sample sub-module without long-term current-carrying capacity are respectively subjected to 168-hour long-term current-carrying test.

5. The flexible DC converter valve destructive testing method of claim 1, wherein, The IGBT sample sub-module with long-term current-carrying capacity comprises an upper tube IGBT device, a lower tube IGBT device, an upper tube anti-parallel diode, a lower tube anti-parallel diode, a direct current capacitor, a resistor and a bypass switch; the upper tube anti-parallel diode is connected in parallel to the upper tube IGBT device, the lower tube anti-parallel diode is connected in parallel to the lower tube IGBT device, one end of the upper tube IGBT device is connected to one end of the direct current capacitor, the other end of the upper tube IGBT device is connected to one end of the lower tube IGBT device, the other end of the lower tube IGBT device is connected to the other end of the direct current capacitor, the resistor is connected in parallel to the direct current capacitor, one end of the bypass switch is connected to one end of the lower tube IGBT device, and the other end of the bypass switch is connected to the other end of the lower tube IGBT device; wherein the failure characteristics of the upper tube IGBT device and the lower tube IGBT device are short circuit. The IGBT without long-term current-carrying capability test sub-module includes an upper tube IGBT device, a lower tube IGBT device, a turn-off thyristor connected in parallel with the lower tube IGBT device, an upper tube anti-parallel diode, a lower tube anti-parallel diode, a direct current capacitor, a resistor and a bypass switch; the upper tube anti-parallel diode is connected in parallel to the upper tube IGBT device, the lower tube anti-parallel diode is connected in parallel to the lower tube IGBT device, one end of the upper tube IGBT device is connected to one end of the direct current capacitor, the other end of the upper tube IGBT device is connected to one end of the lower tube IGBT device, the other end of the lower tube IGBT device is connected to the other end of the direct current capacitor, the turn-off thyristor is connected in parallel to the lower tube IGBT device, the resistor is connected in parallel to the direct current capacitor, one end of the bypass switch is connected to one end of the lower tube IGBT device, and the other end of the bypass switch is connected to the other end of the lower tube IGBT device; wherein the failure characteristics of the upper tube IGBT device and the lower tube IGBT device are open circuit.

6. The flexible DC converter valve destructive testing method of claim 5, wherein, The upper and lower IGBT direct-through destructive test is performed on the IGBT with long-term current-carrying capability test sub-module and the IGBT without long-term current-carrying capability test sub-module, including: The desaturation protection function of the IGBT with long-term current-carrying capability test sub-module and the IGBT without long-term current-carrying capability test sub-module is shielded respectively, and is charged to a first predetermined test voltage; The upper tube IGBT device and the lower tube IGBT device in the IGBT with long-term current-carrying capability test sub-module and the IGBT without long-term current-carrying capability test sub-module are turned on by active triggering, to form an upper and lower tube direct-through short circuit loop; Wherein, the first predetermined test voltage is the latching overvoltage protection setting value of the IGBT with long-term current-carrying capability test sub-module and the IGBT without long-term current-carrying capability test sub-module respectively.

7. The flexible DC converter valve destructive testing method of claim 5, wherein, The bypass switch misoperation destructive test is performed on the IGBT with long-term current-carrying capability test sub-module, including: The operating voltage of the IGBT with long-term current-carrying capability test sub-module is raised, and when the capacitor voltage of the direct current capacitor in the IGBT with long-term current-carrying capability test sub-module reaches a second predetermined test voltage, a command is issued to close the bypass switch to form a short circuit loop; Wherein, the second predetermined test voltage is the latching overvoltage protection setting value of the IGBT with long-term current-carrying capability test sub-module.

8. The flexible DC converter valve destructive testing method of claim 5, wherein, The bypass switch refusal destructive test is performed on the IGBT with long-term current-carrying capability test sub-module, including: The bypass switch in the IGBT with long-term current-carrying capability test sub-module is shielded or removed, so that the bypass switch is disabled; The charging voltage of the IGBT with long-term current-carrying capability test sub-module is raised, and when the capacitor voltage of the direct current capacitor in the IGBT with long-term current-carrying capability test sub-module reaches a third predetermined test voltage, the upper tube IGBT device and the lower tube IGBT device are overvoltage breakdown, and are in a short circuit state; The third predetermined test voltage is an upper limit value of active breakdown voltages of the upper IGBT device and the lower IGBT device of the IGBT test sub-module with long-term current-carrying capability.

9. The flexible DC converter valve destructive testing method of claim 5, wherein, The bypass switch fails to act on the IGBT test sub-module without long-term current-carrying capability, and destructive test is performed. The bypass switch closing loop of the IGBT test sub-module without long-term current-carrying capability is disconnected to simulate switch failure; The charging voltage of the IGBT test sub-module without long-term current-carrying capability is raised, and when the capacitor voltage of the IGBT test sub-module with long-term current-carrying capability reaches a fourth predetermined test voltage, the turn-off thyristor, the upper IGBT device or the upper anti-parallel diode is overvoltage breakdown, and is in a short-circuit state; The fourth predetermined test voltage is an upper limit value of breakdown voltage of the turn-off thyristor of the IGBT test sub-module without long-term current-carrying capability.

10. A flexible DC converter valve destructive test device, characterized by, The method comprises the following steps: An IGBT test sub-module construction module is configured to construct IGBT test sub-modules according to long-term current-carrying capability of IGBT devices in a flexible DC converter valve sub-module, wherein the IGBT test sub-modules include IGBT test sub-modules with long-term current-carrying capability and IGBT test sub-modules without long-term current-carrying capability; An upper and lower IGBT direct-through destructive test module is configured to perform upper and lower IGBT direct-through destructive test on the IGBT test sub-modules with long-term current-carrying capability and the IGBT test sub-modules without long-term current-carrying capability, respectively; A bypass switch mis-closing destructive test module is configured to perform bypass switch mis-closing destructive test on the IGBT test sub-modules with long-term current-carrying capability; A bypass switch fails to act on the IGBT test sub-module without long-term current-carrying capability, and destructive test is performed. A test judgment module is configured to judge the explosion-proof performance of the flexible DC converter valve according to test phenomena of the upper and lower IGBT direct-through destructive test, the bypass switch mis-closing destructive test and the bypass switch fails to act destructive test, and obtain test results.

11. A terminal device, comprising: The computer readable storage medium comprises a stored computer program, wherein when the computer program is running, the computer readable storage medium controls the device where the computer readable storage medium is located to perform the flexible DC converter valve destructive test method.

12. A computer-readable storage medium, characterized in that, The computer readable storage medium comprises a stored computer program, wherein when the computer program is running, the computer readable storage medium controls the device where the computer readable storage medium is located to perform the flexible DC converter valve destructive test method.

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