Flexible direct current valve control temporary lockout timeout protection test method, device and related equipment

Abstract

This application discloses a test method, apparatus, and related equipment for flexible DC valve-controlled temporary blocking timeout protection. The method includes: determining a set of operating conditions based on the main circuit topology and measurement point distribution in the flexible DC system simulation model; combining the action time of the flexible DC valve-controlled temporary blocking timeout protection with the switching failure logic of the grid-side circuit breaker and the valve-side circuit breaker, triggering each target fault condition one by one, acquiring waveform data, and judging whether the flexible DC valve-controlled temporary blocking timeout protection responds according to the design principles; if a failure to respond according to the design principles occurs, the flexible DC valve-controlled temporary blocking timeout protection is determined to have failed the test. This application is simple to operate, has good versatility and strong applicability. The test process does not involve real-time requirements and can be implemented on both non-real-time simulation tools and real-time simulation tools, effectively performing functional testing on flexible DC valve-controlled temporary blocking timeout protection.

Description

Technical Field

[0001] This application relates to the field of power system fault technology, and more specifically, to a test method, apparatus and related equipment for temporary blocking timeout protection of flexible DC valve control. Background Technology

[0002] Modular multilevel converters (MMCs) offer advantages such as modular design, strong scalability, flexible four-quadrant power operation, low AC voltage harmonics, and small footprint. In recent years, they have been widely researched and utilized in areas such as asynchronous interconnection of AC power grids and wind farm integration. In practical applications, the Nan'ao multi-terminal flexible DC transmission project, the Yunnan asynchronous interconnection project, the Shanghai Nanhui flexible DC project, the Zhoushan five-terminal flexible DC project, the Xiamen flexible DC project, the Zhangbei flexible DC power grid project, and the Wudongde power station's ultra-high voltage multi-terminal DC demonstration project transmitting power to Guangdong and Guangxi all utilize the MMC topology.

[0003] As a voltage source converter, to prevent overcurrent damage to fully controlled power electronic devices such as IGBTs (Insulated Gate Bipolar Transistors), the flexible DC valve control system is equipped with temporary lockout protection. This protection is a fast-acting protection; when the flexible DC valve control detects that the arm current exceeds the set value and meets the action delay, it briefly locks the converter valve; when the flexible DC valve control detects that the arm current is less than the return value and meets the return delay, it unlocks the converter valve again. However, when a fault occurs in the control equipment or trigger circuit, it may lead to a situation where the flexible DC valve control actually issues a temporary lockout command, but the converter valve does not actually lock out. To prevent this situation, the flexible DC valve control system is also equipped with a temporary lockout timeout protection function. The principle of this function is: after the temporary lockout protection is activated, it checks whether the maximum value of the current in the six arms meets the return value. If it does not meet the return value, it triggers the temporary lockout timeout protection to trip after a certain period of time.

[0004] To reliably assess and verify the rationality of the criteria and settings for valve-controlled temporary blocking timeout protection, this function needs to be tested. Due to the extremely high safety and stability requirements of power systems, it is impossible to conduct testing of this protection in a production environment. Traditional dynamic simulation tests suffer from drawbacks such as limitations in simulation scale due to site constraints, complex wiring, poor scalability, and limited testing capabilities. Therefore, simulation tools are often required for testing. However, temporary blocking timeout protection is a backup protection for MMC converter valves, and even simulating various short-circuit faults in a simulation system makes it difficult to trigger this protection action. Summary of the Invention

[0005] In view of this, this application provides a test method, apparatus and related equipment for the temporary lockout timeout protection of flexible DC valve control, so as to realize the functional test of the temporary lockout timeout protection of flexible DC valve control.

[0006] To achieve the above objectives, the first aspect of this application provides a test method for temporary lockout timeout protection of a flexible direct current valve, comprising:

[0007] Based on the main circuit topology and measurement point location distribution in the simulation model of the flexible DC system, a set of operating conditions is determined, which includes multiple target fault operating conditions for triggering the flexible DC valve-controlled temporary lockout protection.

[0008] Combining the action time of the flexible DC valve-controlled temporary blocking timeout protection, and the switching failure logic of the grid-side circuit breaker and the valve-side circuit breaker, each target fault condition is triggered one by one in the flexible DC system simulation model, and waveform data in the flexible DC system simulation model is obtained.

[0009] Based on the waveform data, determine whether the flexible direct current valve-controlled temporary lockout timeout protection responds in accordance with the design principles;

[0010] If the flexible direct current valve-controlled temporary lockout timeout protection fails to respond according to the design principles, it is determined that the flexible direct current valve-controlled temporary lockout timeout protection has failed the test.

[0011] Preferably, the process of determining the set of operating conditions based on the main loop topology and measurement point location distribution in the flexible DC system simulation model includes:

[0012] Based on the main circuit topology and measurement point location distribution in the simulation model of the flexible DC system, each fault point and the corresponding fault type are determined.

[0013] Based on each fault point and the corresponding fault type, determine each fault mode;

[0014] For each type of failure:

[0015] In the simulation model of the flexible DC system, a fault matching the fault type is triggered, and it is determined whether the flexible DC valve-controlled temporary lockout protection is activated.

[0016] If so, the fault type is identified as the target fault condition;

[0017] The set of operating conditions consists of various target fault conditions.

[0018] Preferably, the process of determining each fault point based on the main loop topology and measurement point location distribution in the flexible DC system simulation model includes:

[0019] Based on the main circuit topology and measurement point location distribution in the flexible DC system simulation model, the location information of each current measurement point, each resistor, and each reactor in the flexible DC system simulation model is obtained.

[0020] Based on the location information, in the simulation model of the flexible DC system, starting from the converter valve side along the power flow direction, a fault point is set between every two adjacent current measurement points, a fault point is set at both ends of each resistor, a fault point is set at both ends of each reactor, an inter-turn short-circuit fault point is set at each resistor, and an inter-turn short-circuit fault point is set at each reactor.

[0021] Preferably, the process of determining the fault type corresponding to each fault point based on the main loop topology and measurement point location distribution in the flexible DC system simulation model includes:

[0022] Based on the main circuit topology in the simulation model of the flexible DC system, the AC side circuit and the DC side circuit are determined.

[0023] The fault type corresponding to the fault point located in the AC side circuit section is determined as a single-phase ground fault, a two-phase short circuit fault, a two-phase ground fault, or a three-phase ground fault.

[0024] The fault type corresponding to the fault point located in the DC side circuit section is determined to be ground fault or inter-electrode short circuit fault.

[0025] Preferably, the process of triggering each target fault condition one by one in the flexible DC system simulation model, combining the action time of the flexible DC valve-controlled temporary blocking timeout protection and the switching failure logic of the grid-side circuit breaker and the valve-side circuit breaker, includes:

[0026] The DC side of the flexible DC system simulation model is set to a power operation condition of 0.5 pu or more in the power transmission mode, or the DC side of the flexible DC system simulation model is set to a power operation condition of 0.5 pu or more in the STATCOM mode.

[0027] The switch failure logic of the enable grid-side circuit breaker and valve-side circuit breaker is used, and each target fault condition is triggered one by one based on the target duration through fault simulation logic and fault triggering control logic. The target duration is greater than the action time of the flexible DC valve control temporary blocking timeout protection. The fault simulation logic is a simulation logic pre-built at the fault point of each target fault condition according to the fault form. The fault triggering control logic is a control logic pre-built in conjunction with the fault simulation logic.

[0028] Preferably, all the faults are faults that do not pass through the transition resistor; the target duration is twice the action time.

[0029] Preferably, the flexible-vertical system simulation model includes:

[0030] The primary circuit model should include at least the MMC converter valve, flexible DC transformer, AC system, starting circuit, and bridge arm reactor of the flexible DC system.

[0031] It should include at least the typical control functions of flexible DC, such as DC power control, DC voltage control, and AC fault ride-through strategy.

[0032] It should include at least the typical protection functions for flexible DC valve-controlled temporary lockout and flexible DC valve-controlled temporary lockout timeout protection.

[0033] The second aspect of this application provides a test device for temporary lockout timeout protection of a flexible direct current valve, comprising:

[0034] The operating condition determination unit is used to determine the set of operating conditions based on the main circuit topology and the distribution of measurement points in the simulation model of the flexible DC system. The set of operating conditions includes multiple target fault operating conditions for triggering the temporary lockout protection of the flexible DC valve control.

[0035] The fault triggering unit is used to combine the action time of the flexible DC valve-controlled temporary blocking timeout protection with the switching failure logic of the grid-side circuit breaker and the valve-side circuit breaker to trigger each target fault condition one by one in the flexible DC system simulation model and obtain the waveform data in the flexible DC system simulation model.

[0036] The waveform analysis unit is used to determine, based on the waveform data, whether the flexible direct current valve-controlled temporary lockout timeout protection responds in accordance with the design principles;

[0037] The result output unit is used to determine that the flexible DC valve-controlled temporary lockout timeout protection has failed the test if the waveform analysis unit determines that the flexible DC valve-controlled temporary lockout timeout protection has failed to respond according to the design principle.

[0038] A third aspect of this application provides a test device for temporary lockout timeout protection of flexible direct current valve control, comprising: a memory and a processor;

[0039] The memory is used to store programs;

[0040] The processor is used to execute the program to implement each step of the above-described test method for temporary lockout timeout protection of flexible direct current valve control.

[0041] The fourth aspect of this application provides a storage medium having a computer program stored thereon, which, when executed by a processor, implements the various steps of the above-described test method for temporary lockout timeout protection of flexible direct current valve control.

[0042] As described in the above technical solution, this application first determines the set of operating conditions based on the main circuit topology and measurement point location distribution in the flexible DC system simulation model. This set of operating conditions includes multiple target fault conditions used to trigger the flexible DC valve-controlled temporary blocking timeout protection. Then, combining the action time of the flexible DC valve-controlled temporary blocking timeout protection with the switching failure logic of the grid-side circuit breaker and the valve-side circuit breaker, the target fault conditions are triggered one by one in the flexible DC system simulation model, and waveform data is obtained from the model. It is understood that each target fault condition corresponds to a waveform data point, which reflects the electrical characteristics of the converter before and after the triggering of the target fault condition. Next, based on the waveform data, it is determined whether the flexible DC valve-controlled temporary blocking timeout protection responds according to the design principles. If the flexible DC valve-controlled temporary blocking timeout protection fails to respond according to the design principles, it is determined that the flexible DC valve-controlled temporary blocking timeout protection has failed the test. It is understandable that if the flexible DC valve-controlled temporary lockout timeout protection can respond according to the design principles for all target fault conditions, then the function of the flexible DC valve-controlled temporary lockout timeout protection can be determined to be qualified. The technical solution of this application is simple to operate, has good versatility and strong applicability. The testing process does not involve real-time requirements and can be implemented on both non-real-time simulation tools and real-time simulation tools, which can effectively perform functional testing on the flexible DC valve-controlled temporary lockout timeout protection. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the test method for temporary lockout timeout protection of flexible direct current valve control disclosed in the embodiments of this application;

[0045] Figure 2 This is a schematic diagram of a typical topology of a flexible DC back-to-back system disclosed in an embodiment of this application;

[0046] Figure 3 This is a schematic diagram of a typical topology of a high-voltage flexible DC transmission system disclosed in the embodiments of this application;

[0047] Figure 4 This is a schematic diagram of a typical topology of the ultra-high voltage flexible DC transmission system disclosed in the embodiments of this application;

[0048] Figure 5This is a schematic diagram of the distribution of measurement points and the setting of fault points under a typical topology of the flexible DC back-to-back system disclosed in the embodiments of this application;

[0049] Figure 6 This is a schematic diagram of the distribution of measurement points and the setting of fault points under a typical topology of the high-voltage flexible DC transmission system disclosed in the embodiments of this application;

[0050] Figure 7 This is a schematic diagram of the distribution of measurement points and the setting of fault points under a typical topology of the ultra-high voltage flexible DC transmission system disclosed in the embodiments of this application.

[0051] Figure 8 This is a schematic diagram of the circuit breaker switch failure logic disclosed in the embodiments of this application;

[0052] Figure 9 This is a schematic diagram of the positive and negative DC voltage waveforms of the MMC2 converter disclosed in the embodiments of this application;

[0053] Figure 10 This is a schematic diagram of the MMC2 converter arm current waveform disclosed in the embodiments of this application;

[0054] Figure 11 This is a schematic diagram of the MMC2 related flag bits disclosed in the embodiments of this application;

[0055] Figure 12 This is a schematic diagram of the flexible direct current valve-controlled temporary lockout timeout protection test device disclosed in the embodiments of this application;

[0056] Figure 13 This is a schematic diagram of the flexible direct current valve-controlled temporary lockout timeout protection test equipment disclosed in the embodiments of this application. Detailed Implementation

[0057] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0058] The following describes the test method for temporary lockout timeout protection of flexible direct current valve control provided in the embodiments of this application. Please refer to... Figure 1 The test method for temporary lockout timeout protection of flexible direct current valve control provided in this application embodiment may include the following steps:

[0059] Step S101: Determine the set of operating conditions based on the main circuit topology and the distribution of measuring points in the simulation model of the flexible DC system.

[0060] The simulation model of the flexible DC system was built in advance in the simulation tool; the set of operating conditions includes multiple target fault conditions for triggering the flexible DC valve-controlled temporary blocking protection. Specifically, the target fault conditions are abnormal circuit conditions that can trigger the flexible DC valve-controlled temporary blocking protection, such as ground faults, two-phase short-circuit faults, and inter-turn short-circuit faults.

[0061] Step S102: Combining the action time of the flexible DC valve-controlled temporary blocking timeout protection, and the switching failure logic of the grid-side circuit breaker and the valve-side circuit breaker, trigger each target fault condition one by one in the flexible DC system simulation model, and obtain the waveform data in the flexible DC system simulation model.

[0062] Among them, the duration of the fault can be determined based on the action time of the temporary blocking timeout protection of the flexible DC valve control. Only when the duration of the fault reaches the action time of the temporary blocking timeout protection of the flexible DC valve control will the temporary blocking timeout protection of the flexible DC valve control be triggered. The switch refusal logic of the grid-side circuit breaker and the valve-side circuit breaker is used to refuse the converter valve from performing the blocking action when the flexible DC valve control actually issues a temporary blocking command.

[0063] It is understandable that the simulation model of the flexible DC system will generate corresponding waveform data before triggering a target fault condition and after triggering a continuous fault condition. Therefore, each target fault condition in the set of conditions corresponds to a set of waveform data.

[0064] Step S103: Based on the waveform data, determine whether the flexible direct current valve-controlled temporary lockout timeout protection responds in accordance with the design principles.

[0065] In step S104, if a situation occurs where the response fails to meet the design principles, it is determined that the temporary lockout timeout protection of the flexible direct valve control has failed the test.

[0066] Understandably, in the above tests, for each target fault condition in the operating condition set, if the flexible DC valve-controlled temporary blocking timeout protection fails to respond according to design principles even once, the test is considered a failure. Once a failure is detected, the flexible DC valve-controlled temporary blocking timeout protection function needs to be modified and the test repeated. Conversely, if the flexible DC valve-controlled temporary blocking timeout protection responds according to design principles for all target fault conditions, its function is deemed qualified.

[0067] In addition, the target fault conditions that cause the test to fail, as well as the corresponding waveform data, can be recorded so that the temporary lockout timeout protection of the flexible direct current valve can be analyzed and improved in the future.

[0068] This application first determines the set of operating conditions based on the main circuit topology and measurement point distribution in the flexible DC system simulation model. This set includes multiple target fault conditions for triggering the flexible DC valve-controlled temporary blocking timeout protection. Then, combining the action time of the flexible DC valve-controlled temporary blocking timeout protection with the switching failure logic of the grid-side circuit breaker and the valve-side circuit breaker, the target fault conditions are triggered one by one in the flexible DC system simulation model, and waveform data is obtained from the model. It is understood that each target fault condition corresponds to a waveform data point, which reflects the electrical characteristics of the converter before and after the target fault condition is triggered. Next, based on the waveform data, it is determined whether the flexible DC valve-controlled temporary blocking timeout protection responds according to the design principles. If the flexible DC valve-controlled temporary blocking timeout protection fails to respond according to the design principles, it is determined that the flexible DC valve-controlled temporary blocking timeout protection has failed the test. Understandably, if the flexible DC valve-controlled temporary blocking timeout protection can respond according to the design principles for all target fault conditions, then the function of the flexible DC valve-controlled temporary blocking timeout protection can be determined to be qualified. The technical solution of this application is simple to operate, has good versatility and strong applicability. The testing process does not involve real-time requirements and can be implemented on both non-real-time simulation tools and real-time simulation tools, which can effectively perform functional testing on the flexible DC valve-controlled temporary blocking timeout protection.

[0069] In some embodiments of this application, the simulation model of the flexible vertical transmission system mentioned above may include:

[0070] A1 includes at least the primary circuit model of the flexible DC system MMC converter valve, flexible DC transformer, AC system, starting circuit, and bridge arm reactor.

[0071] A2 includes at least the typical control functions of flexible DC, such as DC power control, DC voltage control, and AC fault ride-through strategy.

[0072] A3 includes at least the typical protection functions for flexible DC valve-controlled temporary lockout and flexible DC valve-controlled temporary lockout timeout protection.

[0073] Among them, flexible DC systems at both ends can be divided into flexible DC back-to-back systems, high-voltage flexible DC transmission systems, and ultra-high-voltage flexible DC transmission systems.

[0074] For a flexible vertical back-to-back system, the entire system has a symmetrical monopolar (pseudo-bipolar) structure, and a typical topology diagram is shown below. Figure 2 As shown, each end contains one converter (MMC1, MMC2) and does not involve a grounding electrode. Clamping is achieved through the flexible DC-DC converter valve side.

[0075] For high-voltage flexible DC transmission systems, symmetrical monopole (pseudo-bipolar) or symmetrical bipolar (true bipolar) structures can be adopted. A typical topology diagram under true bipolar is shown below. Figure 3 As shown, it includes two converter stations (MMC1 and MMC2). Each converter station has one MMC converter for both positive and negative poles, and each has a grounding electrode. The two MMC converters are connected by a DC line.

[0076] For ultra-high voltage (UHV) flexible direct current (DC) transmission systems, a symmetrical bipolar (true bipolar) structure can be adopted. Compared to high voltage (HV) flexible DC transmission systems, UHV flexible DC transmission systems use a structure where each electrode employs two MMC converters connected in series. A typical topology diagram of an UHV flexible DC transmission system is shown below. Figure 4 As shown, it includes two converter stations (MMC1 and MMC2). The two MMC converter stations are connected by a DC line and are each equipped with a grounding electrode. Each converter station has two MMC converters on both the positive and negative poles.

[0077] In some embodiments of this application, the process of determining the set of operating conditions based on the main loop topology and measurement point location distribution in the flexible DC system simulation model may include:

[0078] S1. Based on the main circuit topology and measurement point location distribution in the simulation model of the flexible DC system, determine each fault point and the corresponding fault type.

[0079] The fault point is used to attempt to trigger the flexible DC valve-controlled temporary blocking protection. For example, a fault point can be set between every two adjacent current measurement points, or at both ends of a resistor, and so on. The fault type corresponding to a fault point is the type of fault set at that fault point, such as ground fault, short circuit fault, etc.

[0080] S2, based on each fault point and the corresponding fault type, determine each fault type.

[0081] It is understandable that a fault point can correspond to multiple fault types. For example, for a fault point located at the inflow end of the valve-side circuit breaker, the corresponding fault types can include single-phase grounding, two-phase grounding, three-phase grounding, and phase-to-phase short circuit. So, assuming the total number of fault points is M and the total number of fault types is N, it is easy to see that N > M.

[0082] S3, for each type of fault:

[0083] In the simulation model of the flexible DC system, a fault matching the fault type is triggered, and it is determined whether the flexible DC valve-controlled temporary lockout protection is activated.

[0084] If so, the fault type is identified as the target fault condition.

[0085] After traversing all fault types, multiple target fault conditions are obtained, and the set of conditions is composed of each target fault condition.

[0086] For example, assuming there are a total of N types of faults, which constitute a set of fault types, then the process of determining the set of operating conditions for each fault type in S3 above can include:

[0087] S31, run the simulation model and switch the DC operation to a high-power operating condition (which can be either power transfer mode or STATCOM mode, with the power level greater than 0.5 pu of the current mode).

[0088] S32, set variable i, where the initial value of i is 1; set variable j, where the initial value of j is 0; set variable k, where the initial value of k is 0.

[0089] S33, trigger the i-th fault mode in the set of fault modes and observe the system response.

[0090] S34. If the valve-controlled temporary lockout protection of the flexible direct feed end is activated, the fault type is recorded in the operating condition set S_TB of the flexible direct feed end, and j++ is set.

[0091] S35, if the valve-controlled temporary lockout protection of the flexible DC receiving end is activated, then the fault point is recorded in the working condition set R_TB of the flexible DC receiving end, and k++ is set.

[0092] S36 restores the flexible DC system to the operating conditions in S31.

[0093] S37, increment i, check if i is greater than N. If i ≤ N, return to execute S33; otherwise, complete the process of determining the set of working conditions.

[0094] Thus, the set of operating conditions S_TB for the flexible DC transmission end containing j target fault conditions and the set of operating conditions R_TB for the flexible DC receiving end containing k target fault conditions are obtained respectively.

[0095] In some embodiments of this application, the faults mentioned above are all faults that do not pass through the transition resistor; the duration of the target mentioned above is twice the action time.

[0096] In some embodiments of this application, the process of determining each fault point in S11 based on the main circuit topology and measurement point location distribution in the flexible DC system simulation model may include:

[0097] S111, based on the main circuit topology and measurement point location distribution in the flexible DC system simulation model, obtain the location information of each current measurement point, each resistor, and each reactor in the flexible DC system simulation model.

[0098] S112, Based on this location information, in the simulation model of the flexible DC system, starting from the converter valve side along the power flow direction, a fault point is set between every two adjacent current measurement points, a fault point is set at both ends of each resistor, a fault point is set at both ends of each reactor, an inter-turn short-circuit fault point is set at each resistor, and an inter-turn short-circuit fault point is set at each reactor.

[0099] The above lists all possible fault points. In practical applications, some or all of the fault points can be selected for testing as needed.

[0100] For example, Figure 5 A schematic diagram of the measurement point distribution and fault point setting under a typical topology of a flexible DC back-to-back system is given. The starting circuit is located on the valve side (it can also be placed on the grid side), and the bridge arm reactor is located near the AC side (it can also be placed near the DC bus). Figure 4 As shown, the simulation model of the flexible vertical shaft system includes 13 fault points F1 to F13 at one end, and the fault points at the other end are symmetrically distributed with these fault points.

[0101] Figure 6 A schematic diagram of the measurement point distribution and fault point setting under a typical topology of a high-voltage flexible DC transmission system is given. The starting circuit is located on the grid side (it can also be placed on the valve side in practice), and the bridge arm reactor is located near the DC side (it can also be placed near the AC side in practice). Figure 5 As shown, the simulation model of the flexible DC system includes 17 fault points of single station single pole F1 to F17, and the fault points of the local pole and the opposite station are symmetrically distributed with these fault points.

[0102] Figure 7 A schematic diagram of the distribution of measuring points and fault location under a typical topology of an ultra-high voltage flexible direct current transmission system is given. The starting circuit is located on the grid side (it can also be placed on the valve side), and the bridge arm reactor is located near the DC side (it can also be placed near the AC side). Figure 6 As shown, the simulation model of the flexible DC system includes 29 fault points of single station single pole F1 to F29. The faults of the pole and the station are symmetrically distributed with these fault points.

[0103] In some embodiments of this application, the process of determining the fault type of each fault point based on the main circuit topology and measurement point location distribution in the flexible DC system simulation model in step S11 may include:

[0104] S113. Based on the main circuit topology in the simulation model of the flexible DC system, determine the AC side circuit and the DC side circuit.

[0105] S114 determines the fault type of the fault point located in the AC side circuit section as a single-phase ground fault, a two-phase short-circuit fault, a two-phase ground fault, or a three-phase ground fault.

[0106] S115 determines the fault type of the fault point located in the DC side circuit section as ground fault or inter-electrode short circuit fault.

[0107] For example, please refer to Figure 5 The fault types for fault points F1 and F3 can be set as single-phase grounding, three-phase grounding, phase-to-phase short circuit, or two-phase grounding; the fault type for fault point F2 can be set as at least one of single-phase grounding, three-phase grounding, phase-to-phase short circuit, two-phase grounding, and resistor turn-to-turn short circuit; the fault types for fault points F4 and F9 can be set as single-phase grounding, phase-to-phase short circuit, or reactor turn-to-turn short circuit; the fault types for fault points F5 and F10 can be set as single-phase grounding or phase-to-phase short circuit; the fault types for fault points F6 and F11 can be set as inter-module short circuit or phase-to-phase short circuit; the fault types for fault points F7 and F12 can be set as grounding fault; the fault type for fault point F8 can be set as grounding fault or inter-electrode short circuit; the fault type for fault point F12 can be set as grounding fault; and the fault type for fault point F13 can be set as grounding fault or inter-electrode short circuit.

[0108] Please see Figure 6 The fault types of fault points F1 and F2 can be set to at least one of single-phase grounding, three-phase grounding, phase-to-phase short circuit, and two-phase grounding; the fault types of fault points F3 and F10 can be set to inter-module short circuit or phase-to-phase short circuit; the fault types of fault points F4 and F11 can be set to single-phase grounding or phase-to-phase short circuit; the fault types of fault points F5 and F12 can be set to single-phase grounding, phase-to-phase short circuit, or reactor turn-to-turn short circuit; the fault type of fault point F6 can be set to grounding fault, bridge arm short circuit, or valve group short circuit; the fault types of fault points F7, F8, F14, F15, and F16 can be set to grounding fault; the fault type of fault point F9 can be set to grounding fault or inter-electrode short circuit; and the fault type of fault point F13 can be set to grounding fault, bridge arm short circuit, or inter-electrode short circuit.

[0109] Please see Figure 7The fault types for fault points F1, F2, F12, and F13 can be set as single-phase grounding, three-phase grounding, phase-to-phase short circuit, or two-phase grounding; the fault types for fault points F3, F8, F14, and F19 can be set as inter-module short circuit or phase-to-phase short circuit; the fault types for fault points F4, F9, F15, and F20 can be set as single-phase grounding or phase-to-phase short circuit; the fault types for fault points F5, F10, F16, and F21 can be set as single-phase grounding, phase-to-phase short circuit, or reactor turn-to-turn short circuit; the fault types for fault points F6, F11, and F17 can be set as grounding fault or bridge arm short circuit; the fault types for fault points F7 and F18 can be set as valve group short circuit; and the fault types for fault points F22 to F29 can be set as grounding fault.

[0110] In some embodiments of this application, step S102, combined with the operating time of the flexible DC valve-controlled temporary blocking timeout protection and the switching failure logic of the grid-side circuit breaker and the valve-side circuit breaker, is a process of triggering each target fault condition one by one in the flexible DC system simulation model, which may include:

[0111] S1, switch the DC power to the preset high-power operating condition, or switch the DC power to the reactive power operating condition with the preset pu value in STATCOM mode.

[0112] Specifically, the DC side of the flexible DC system simulation model is set to a power operation condition of 0.5 pu or higher under power transmission mode, or the DC side of the flexible DC system simulation model is set to a power operation condition of 0.5 pu or higher under STATCOM mode.

[0113] S2 enables the switching failure logic of the grid-side circuit breaker and the valve-side circuit breaker, and triggers each target fault condition one by one based on the target duration through fault simulation logic and fault triggering control logic.

[0114] The duration of the target is greater than the action time of the temporary blocking timeout protection of the flexible direct valve control. The fault simulation logic is a simulation logic pre-built at the fault point of each target fault condition according to the fault mode of each target fault condition. The fault trigger control logic is a control logic pre-built in conjunction with the fault simulation logic.

[0115] For example, Figure 8 A circuit breaker switch failure logic is presented. When it is not necessary to simulate switch failure, the failure logic enable flag is set to 0, and the circuit breaker ultimately executes the closing or tripping command from the control and protection logic. When it is necessary to simulate switch failure, the failure logic enable flag is set to 1, and the circuit breaker receives the closing command as the closing command.

[0116] The following describes, in conjunction with the above embodiments, a specific example for the flexible direct feed end, detailing the process of testing the valve-controlled temporary lockout timeout protection of the flexible direct feed end using the aforementioned operating condition set S_TB, which includes j target fault conditions. Specifically, the process may include:

[0117] S1, build the switching failure logic of the flexible direct transmission end network side circuit breaker and valve side circuit breaker in the model.

[0118] S2, run the simulation model and switch the DC operation to a high-power operating condition (which can be either power transfer mode or STATCOM mode, with the power level greater than 0.5 pu of the current mode).

[0119] S3 enables the circuit breaker switch failure logic of the grid-side circuit breaker and valve-side circuit breaker at the flexible direct-feed end.

[0120] S4, set the initial value of variable x to 1 and the initial value of variable p to 0.

[0121] S5, triggers the x-th target fault condition in the set of operating conditions S_TB;

[0122] S6. Analyze the rationality of the valve-controlled temporary lockout timeout protection action at the flexible direct feed end based on the test waveform.

[0123] S7. If the valve-controlled temporary lockout timeout protection at the flexible direct feed end operates correctly or does not operate correctly, the target fault condition test is valid, and the target fault condition is recorded in the condition set S_TBL of the flexible direct feed end, and p++ is set.

[0124] S8. If the valve-controlled temporary lockout timeout protection action at the flexible direct feed end does not conform to the design principle, then the valve-controlled temporary lockout timeout protection is determined to have failed the test, and the test ends.

[0125] S9 restores the flexible DC system to the operating conditions in S2.

[0126] S10, increment x, and determine if x is greater than j. If x ≤ j, return to execute S5; otherwise, complete this valve-controlled temporary lockout timeout protection test.

[0127] At this point, the valve-controlled temporary lockout timeout protection test was successfully completed, and the valve-controlled temporary lockout timeout protection action condition set S_TBL was obtained at the flexible direct delivery end. It contains a total of p specific target fault conditions that can effectively trigger the valve-controlled temporary lockout timeout protection to operate correctly or not operate correctly.

[0128] The following describes, in conjunction with the above embodiments, a specific example of testing the valve-controlled temporary blocking timeout protection of the flexible DC receiving end using the aforementioned operating condition set R_TB containing k target fault conditions. Specifically, the process may include:

[0129] S1, build the switching failure logic of the flexible DC receiving end network side circuit breaker and valve side circuit breaker in the model.

[0130] S2, run the simulation model and switch the DC operation to a high-power operating condition (which can be either power transfer mode or STATCOM mode, with the power level greater than 0.5 pu of the current mode).

[0131] S3 enables the logic for the refusal to operate of the flexible DC receiving-side circuit breaker and the valve-side circuit breaker.

[0132] S4, set the initial value of variable y to 1 and the initial value of variable q to 0.

[0133] S5 triggers the y-th target fault condition in the set of operating conditions R_TB;

[0134] S6. Analyze the rationality of the temporary lockout timeout protection action of the receiving end valve based on the test waveform.

[0135] S7. If the valve-controlled temporary lockout timeout protection at the flexible DC receiving end operates correctly or does not operate correctly, then the target fault condition test is valid. Record the target fault condition in the condition set R_TB at the flexible DC receiving end, and simultaneously increment q.

[0136] S8. If the valve-controlled temporary lockout timeout protection action at the flexible DC receiving end does not conform to the design principles, then the valve-controlled temporary lockout timeout protection is determined to have failed the test, and the test ends.

[0137] S9 restores the flexible DC system to the operating conditions in S2.

[0138] S10, increment y, and determine if y is greater than k. If y ≤ k, return to execute S5; otherwise, complete this valve-controlled temporary lockout timeout protection test.

[0139] At this point, the valve-controlled temporary lockout timeout protection test was successfully completed, and the set of valve-controlled temporary lockout timeout protection operating conditions R_TBL at the flexible DC receiving end was obtained. It contains q specific target fault conditions that can effectively trigger the valve-controlled temporary lockout timeout protection to operate correctly or not operate correctly.

[0140] Based on the above method for testing the valve-controlled temporary blocking timeout protection of the flexible DC sending end or the flexible DC receiving end using the target fault conditions in the set of operating conditions, the following is a test method and test results of a certain flexible DC back-to-back DC receiving end valve-controlled temporary blocking timeout protection (protection delay of 1s) under a certain target fault condition, combined with specific parameters.

[0141] S1: Establish a simulation model of the flexible DC system in the simulation tool. The established model shall include at least the following: the primary main circuit model of the flexible DC system MMC converter valve, flexible DC transformer, AC system, starting circuit, bridge arm reactor, etc.; typical flexible DC control functions including DC power control, DC voltage control, and AC fault ride-through strategy; and typical flexible DC protection functions including flexible DC valve-controlled temporary blocking protection and flexible DC valve-controlled temporary blocking timeout protection.

[0142] S2, according to Figure 5 For each fault point shown, fault simulation logic and corresponding fault triggering control logic are built at the corresponding positions in the main circuit of the model. All faults are those that do not pass through a transition resistor; the fault duration is twice the temporary blocking timeout protection action time, i.e., 2 seconds.

[0143] S3, run the simulation model, and switch the DC operation to the receiving end STATCOM mode 0.75pu reactive power operation condition.

[0144] S4 triggers an inter-pole short circuit fault at the F13 fault point on the flexible DC receiving end, causing a temporary valve-controlled lockout action on the flexible DC receiving end.

[0145] S5 restores the flexible DC system to the receiving end STATCOM mode with 0.75 pu reactive power operation.

[0146] S6, build the switching failure logic of the flexible DC receiving end network side circuit breaker and valve side circuit breaker in the model.

[0147] S7, run the simulation model, and switch the DC operation to the receiving end STATCOM mode 0.75pu reactive power operation condition.

[0148] S8 enables the logic for the refusal to operate of the flexible DC receiving-side circuit breaker and the valve-side circuit breaker.

[0149] S9 triggers an inter-pole short circuit fault at fault point F13. The flexible DC receiving end valve-controlled temporary lockout protection does not return after its operation, and the flexible DC receiving end valve-controlled temporary lockout timeout protection operates.

[0150] Figures 9 to 12 The waveform diagram is given for a short-circuit fault at point F13 in the receiving end of the S4 system operating in STATCOM mode with 0.75 pu reactive power. Figure 9 The waveforms are the positive and negative DC voltages of the MMC2 converter. Figure 10 The waveform of the MMC2 converter bridge arm current is shown. Figure 11 The flags are: MMC2 valve-controlled temporary lockout protection action flag, MMC2 valve-controlled temporary lockout timeout protection action flag, MMC2 DC protection trip AC circuit breaker flag, MMC2 valve-controlled bridge arm overcurrent protection trip flag, MMC2 valve-controlled bipolar short circuit protection trip flag, MMC2 bridge arm differential protection 3-stage trip flag, and MMC2 valve-controlled trip request flag.

[0151] As can be seen from the figure, after the fault, the valve-controlled temporary blocking action of the flexible DC receiving end was activated. The duration of the temporary blocking flag was approximately 155.8ms. The valve-controlled temporary blocking timeout protection of the flexible DC receiving end did not activate. The valve-controlled bridge arm overcurrent protection, bipolar short circuit protection, and other protection actions of the flexible DC receiving end tripped.

[0152] The following describes the flexible direct current valve-controlled temporary lockout timeout protection test device provided in the embodiments of this application. The flexible direct current valve-controlled temporary lockout timeout protection test device described below can be referred to in correspondence with the flexible direct current valve-controlled temporary lockout timeout protection test method described above.

[0153] Please see Figure 12 The flexible direct current valve-controlled temporary lockout timeout protection test device provided in this application embodiment may include:

[0154] The operating condition determination unit 21 is used to determine the set of operating conditions based on the main circuit topology, measurement point location distribution and the action time of the flexible DC valve-controlled temporary blocking timeout protection in the simulation model of the flexible DC system. The set of operating conditions includes multiple target fault operating conditions for triggering the flexible DC valve-controlled temporary blocking timeout protection.

[0155] The fault triggering unit 22 is used to combine the switching failure logic of the grid-side circuit breaker and the valve-side circuit breaker to trigger each target fault condition one by one in the flexible DC system simulation model, and to acquire the waveform data in the flexible DC system simulation model.

[0156] The waveform analysis unit 23 is used to determine, based on the waveform data, whether the flexible direct current valve-controlled temporary lockout timeout protection responds in accordance with the design principles;

[0157] The result output unit 24 is used to determine that the flexible direct current valve-controlled temporary blocking timeout protection has failed the test if the waveform analysis unit determines that the flexible direct current valve-controlled temporary blocking timeout protection has failed to respond according to the design principle.

[0158] In some embodiments of this application, the process by which the operating condition determination unit 21 determines the set of operating conditions based on the main loop topology and the distribution of measurement points in the simulation model of the flexible DC system may include:

[0159] Based on the main circuit topology and measurement point location distribution in the simulation model of the flexible DC system, each fault point and the corresponding fault type are determined.

[0160] Based on each fault point and the corresponding fault type, determine each fault mode;

[0161] For each type of failure:

[0162] In the simulation model of the flexible DC system, a fault matching the fault type is triggered, and it is determined whether the flexible DC valve-controlled temporary lockout protection is activated.

[0163] If so, the fault type is identified as the target fault condition;

[0164] The set of operating conditions consists of various target fault conditions.

[0165] In some embodiments of this application, the process by which the operating condition determination unit 21 determines each fault point based on the main loop topology and measurement point location distribution in the flexible DC system simulation model may include:

[0166] Based on the main circuit topology and measurement point location distribution in the flexible DC system simulation model, the location information of each current measurement point, each resistor, and each reactor in the flexible DC system simulation model is obtained.

[0167] Based on the location information, in the simulation model of the flexible DC system, starting from the converter valve side along the power flow direction, a fault point is set between every two adjacent current measurement points, a fault point is set at both ends of each resistor, a fault point is set at both ends of each reactor, an inter-turn short-circuit fault point is set at each resistor, and / or an inter-turn short-circuit fault point is set at each reactor.

[0168] In some embodiments of this application, the process by which the operating condition determination unit 21 determines the fault type corresponding to each fault point based on the main loop topology and measurement point location distribution in the flexible DC system simulation model may include:

[0169] Based on the main circuit topology in the simulation model of the flexible DC system, the AC side circuit and the DC side circuit are determined.

[0170] The fault type corresponding to the fault point located in the AC side circuit section is determined as a single-phase ground fault, a two-phase short circuit fault, a two-phase ground fault, or a three-phase ground fault.

[0171] The fault type corresponding to the fault point located in the DC side circuit section is determined to be ground fault or inter-electrode short circuit fault.

[0172] In some embodiments of this application, the fault triggering unit 22, in conjunction with the operating time of the flexible DC valve-controlled temporary blocking timeout protection and the switching failure logic of the grid-side circuit breaker and the valve-side circuit breaker, triggers each target fault condition one by one in the flexible DC system simulation model, including:

[0173] The DC side of the flexible DC system simulation model is set to a power operation condition of 0.5 pu or more in the power transmission mode, or the DC side of the flexible DC system simulation model is set to a power operation condition of 0.5 pu or more in the STATCOM mode.

[0174] The switch failure logic of the enable grid-side circuit breaker and valve-side circuit breaker is used, and each target fault condition is triggered one by one based on the target duration through fault simulation logic and fault triggering control logic. The target duration is greater than the action time of the flexible DC valve control temporary blocking timeout protection. The fault simulation logic is a simulation logic pre-built at the fault point of each target fault condition according to the fault form. The fault triggering control logic is a control logic pre-built in conjunction with the fault simulation logic.

[0175] In some embodiments of this application, the faults are all faults that do not pass through the transition resistor; the target duration is twice the action time.

[0176] In some embodiments of this application, the flexible vertical transmission system simulation model may include:

[0177] The primary circuit model should include at least the MMC converter valve, flexible DC transformer, AC system, starting circuit, and bridge arm reactor of the flexible DC system.

[0178] It should include at least the typical control functions of flexible DC, such as DC power control, DC voltage control, and AC fault ride-through strategy.

[0179] It should include at least the typical protection functions for flexible DC valve-controlled temporary lockout and flexible DC valve-controlled temporary lockout timeout protection.

[0180] The flexible DC valve-controlled temporary lockout timeout protection test device provided in this application embodiment can be applied to flexible DC valve-controlled temporary lockout timeout protection test equipment, such as computers. Optionally, Figure 13 The hardware structure block diagram of the test equipment for temporary lockout timeout protection of flexible direct current valve control is shown. (Refer to...) Figure 13 The hardware structure of the flexible direct current valve control temporary lockout timeout protection test equipment may include: at least one processor 31, at least one communication interface 32, at least one memory 33 and at least one communication bus 34.

[0181] In this embodiment, the number of processor 31, communication interface 32, memory 33 and communication bus 34 is at least one, and processor 31, communication interface 32 and memory 33 communicate with each other through communication bus 34;

[0182] The processor 31 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0183] The memory 32 may include high-speed RAM, and may also include non-volatile memory, such as at least one disk storage device;

[0184] The memory 33 stores a program, and the processor 31 can call the program stored in the memory 33. The program is used for:

[0185] Based on the main circuit topology and measurement point location distribution in the simulation model of the flexible DC system, a set of operating conditions is determined, which includes multiple target fault operating conditions for triggering the flexible DC valve-controlled temporary lockout protection.

[0186] Combining the action time of the flexible DC valve-controlled temporary blocking timeout protection, and the switching failure logic of the grid-side circuit breaker and the valve-side circuit breaker, each target fault condition is triggered one by one in the flexible DC system simulation model, and waveform data in the flexible DC system simulation model is obtained.

[0187] Based on the waveform data, determine whether the flexible direct current valve-controlled temporary lockout timeout protection responds in accordance with the design principles;

[0188] If the flexible direct current valve-controlled temporary lockout timeout protection fails to respond according to the design principles, it is determined that the flexible direct current valve-controlled temporary lockout timeout protection has failed the test.

[0189] Optionally, the refined and extended functions of the program can be found in the description above.

[0190] This application embodiment also provides a storage medium that can store a program suitable for execution by a processor, the program being used for:

[0191] Based on the main circuit topology and measurement point location distribution in the simulation model of the flexible DC system, a set of operating conditions is determined, which includes multiple target fault operating conditions for triggering the flexible DC valve-controlled temporary lockout protection.

[0192] Combining the action time of the flexible DC valve-controlled temporary blocking timeout protection, and the switching failure logic of the grid-side circuit breaker and the valve-side circuit breaker, each target fault condition is triggered one by one in the flexible DC system simulation model, and waveform data in the flexible DC system simulation model is obtained.

[0193] Based on the waveform data, determine whether the flexible direct current valve-controlled temporary lockout timeout protection responds in accordance with the design principles;

[0194] If the flexible direct current valve-controlled temporary lockout timeout protection fails to respond according to the design principles, it is determined that the flexible direct current valve-controlled temporary lockout timeout protection has failed the test.

[0195] Optionally, the refined and extended functions of the program can be found in the description above.

[0196] In summary:

[0197] This application first determines the set of operating conditions based on the main circuit topology and measurement point location distribution in the flexible DC system simulation model. This set of operating conditions includes multiple target fault conditions used to trigger the flexible DC valve-controlled temporary blocking timeout protection. Then, combining the action time of the flexible DC valve-controlled temporary blocking timeout protection with the switching failure logic of the grid-side circuit breaker and the valve-side circuit breaker, each target fault condition is triggered one by one in the flexible DC system simulation model, and waveform data is obtained from the model. It is understood that each target fault condition corresponds to a waveform data point, which reflects the electrical characteristics of the converter before and after the triggering of the target fault condition. Next, based on the waveform data, it is determined whether the flexible DC valve-controlled temporary blocking timeout protection responds according to the design principles. If the flexible DC valve-controlled temporary blocking timeout protection fails to respond according to the design principles, it is determined that the flexible DC valve-controlled temporary blocking timeout protection has failed the test. It is understandable that if the flexible DC valve-controlled temporary lockout timeout protection can respond according to the design principles for all target fault conditions, then the function of the flexible DC valve-controlled temporary lockout timeout protection can be determined to be qualified. The technical solution of this application is simple to operate, requiring no modification to the control and protection logic; testing can be completed simply by building a simple logic in a simulation tool. It has good completeness and can conduct functional verification of the valve-controlled temporary lockout timeout protection for valve-controlled temporary lockout conditions caused by different fault locations and fault modes. It can comprehensively verify the temporary blocking timeout protection function; it has strong applicability and can test the valve-controlled temporary blocking timeout protection function of different technical routes at the sending and receiving ends of flexible DC back-to-back systems, high-voltage flexible DC transmission systems, and ultra-high-voltage flexible DC transmission systems; the test process does not involve real-time requirements and has good compatibility. It can be implemented on non-real-time simulation tools (such as PSCAD / EMTDC, MATLAB / SIMULINK) or real-time simulation tools (such as RTDS, RTLAB, Hypersim), which can effectively perform functional testing on the valve-controlled temporary blocking timeout protection of flexible DC transmission systems.

[0198] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0199] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can be referred to each other.

[0200] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A test method for temporary lockout timeout protection of a flexible direct current valve, characterized in that, include: Based on the main circuit topology and measurement point location distribution in the simulation model of the flexible DC system, a set of operating conditions is determined, which includes multiple target fault operating conditions for triggering the flexible DC valve-controlled temporary lockout protection. Combining the action time of the flexible DC valve-controlled temporary blocking timeout protection, and the switching failure logic of the grid-side circuit breaker and the valve-side circuit breaker, each target fault condition is triggered one by one in the flexible DC system simulation model, and waveform data in the flexible DC system simulation model is obtained. Based on the waveform data, determine whether the flexible direct current valve-controlled temporary lockout timeout protection responds in accordance with the design principles; If the flexible direct current valve-controlled temporary lockout timeout protection fails to respond according to the design principles, it is determined that the flexible direct current valve-controlled temporary lockout timeout protection has failed the test.

2. The method according to claim 1, characterized in that, The process of determining the set of operating conditions based on the main loop topology and measurement point location distribution in the simulation model of the flexible DC system includes: Based on the main circuit topology and measurement point location distribution in the simulation model of the flexible DC system, each fault point and the corresponding fault type are determined. Based on each fault point and the corresponding fault type, determine each fault mode; For each type of failure: In the simulation model of the flexible DC system, a fault matching the fault type is triggered, and it is determined whether the flexible DC valve-controlled temporary lockout protection is activated. If so, the fault type is identified as the target fault condition; The set of operating conditions consists of various target fault conditions.

3. The method according to claim 2, characterized in that, The process of determining each fault point based on the main circuit topology and measurement point location distribution in the flexible DC system simulation model includes: Based on the main circuit topology and measurement point location distribution in the flexible DC system simulation model, the location information of each current measurement point, each resistor, and each reactor in the flexible DC system simulation model is obtained. Based on the location information, in the simulation model of the flexible DC system, starting from the converter valve side along the power flow direction, a fault point is set between every two adjacent current measurement points, a fault point is set at both ends of each resistor, a fault point is set at both ends of each reactor, an inter-turn short-circuit fault point is set at each resistor, and an inter-turn short-circuit fault point is set at each reactor.

4. The method according to claim 3, characterized in that, The process of determining the fault type corresponding to each fault point based on the main circuit topology and measurement point location distribution in the flexible DC system simulation model includes: Based on the main circuit topology in the simulation model of the flexible DC system, the AC side circuit and the DC side circuit are determined. The fault type corresponding to the fault point located in the AC side circuit section is determined as a single-phase ground fault, a two-phase short circuit fault, a two-phase ground fault, or a three-phase ground fault. The fault type corresponding to the fault point located in the DC side circuit section is determined to be ground fault or inter-electrode short circuit fault.

5. The method according to claim 2, characterized in that, The process of triggering each target fault condition one by one in the flexible DC system simulation model, combining the action time of the flexible DC valve-controlled temporary blocking timeout protection and the switching failure logic of the grid-side circuit breaker and the valve-side circuit breaker, includes: The simulation model of the flexible DC system is set to a power operation condition of 0.5 pu or higher in the power transmission mode, or the simulation model of the flexible DC system is set to a power operation condition of 0.5 pu or higher in the STATCOM mode. The switch failure logic of the enable grid-side circuit breaker and valve-side circuit breaker is used, and each target fault condition is triggered one by one based on the target duration through fault simulation logic and fault triggering control logic. The target duration is greater than the action time of the flexible DC valve control temporary blocking timeout protection. The fault simulation logic is a simulation logic pre-built at the fault point of each target fault condition according to the fault form. The fault triggering control logic is a control logic pre-built in conjunction with the fault simulation logic.

6. The method according to claim 5, characterized in that, All the faults mentioned are faults that do not pass through the transition resistor; the duration of the target is twice the duration of the action.

7. The method according to any one of claims 1 to 6, characterized in that, The simulation model of the flexible vertical transmission system includes: The primary circuit model should include at least the MMC converter valve, flexible DC transformer, AC system, starting circuit, and bridge arm reactor of the flexible DC system. It should include at least the typical control functions of flexible DC, such as DC power control, DC voltage control, and AC fault ride-through strategy. It should include at least the typical protection functions for flexible DC valve-controlled temporary lockout and flexible DC valve-controlled temporary lockout timeout protection.

8. A test device for temporary lockout timeout protection of a flexible direct current valve control system, characterized in that, include: The operating condition determination unit is used to determine the set of operating conditions based on the main circuit topology and the distribution of measurement points in the simulation model of the flexible DC system. The set of operating conditions includes multiple target fault operating conditions for triggering the temporary lockout protection of the flexible DC valve control. The fault triggering unit is used to combine the action time of the flexible DC valve-controlled temporary blocking timeout protection with the switching failure logic of the grid-side circuit breaker and the valve-side circuit breaker to trigger each target fault condition one by one in the flexible DC system simulation model and obtain the waveform data in the flexible DC system simulation model. The waveform analysis unit is used to determine, based on the waveform data, whether the flexible direct current valve-controlled temporary lockout timeout protection responds in accordance with the design principles; The result output unit is used to determine that the flexible DC valve-controlled temporary lockout timeout protection has failed the test if the waveform analysis unit determines that the flexible DC valve-controlled temporary lockout timeout protection has failed to respond according to the design principle.

9. A test device for temporary lockout timeout protection of a flexible direct current valve control system, characterized in that, include: Memory and processor; The memory is used to store programs; The processor is used to execute the program to implement each step of the test method for temporary lockout timeout protection of flexible direct current valve control as described in any one of claims 1 to 7.

10. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements each step of the test method for temporary lockout timeout protection of flexible direct current valve control as described in any one of claims 1 to 7.

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