Method and device for setting short-circuit current control parameters of a voltage source converter

Abstract

The application belongs to the field of electric power, and discloses a setting method and device for short-circuit current control parameters of a voltage source converter, comprising the following steps: determining a short-circuit current limit control value, and simulating and calculating the short-circuit current of a bus to screen out key buses; performing full-type fault scanning on the key buses, identifying key fault forms causing the short-circuit current to exceed the standard, and recording corresponding first converter grid-connected point residual voltages; introducing boundary conditions under the key fault forms, and recording second converter grid-connected point residual voltages when the short-circuit current exceeds the standard under each boundary condition; determining the maximum residual voltage value of the first converter grid-connected point residual voltage and the second converter grid-connected point residual voltage, and determining the sum of a preset margin and the maximum residual voltage value as a candidate starting setting value of a low-voltage current-limiting strategy; in the case where the candidate starting setting value does not exceed the upper limit of the starting setting value under the constraint of voltage support demand, the candidate starting setting value is determined as a target starting setting value.

Description

Technical Field

[0001] This invention belongs to the field of power, and particularly relates to a method and apparatus for setting short-circuit current control parameters of a voltage source converter. Background Technology

[0002] With the rapid development of new energy power generation and DC transmission technologies, the penetration rate of voltage source converters (VSCs) in power systems is continuously increasing. VSCs typically possess low voltage ride-through capability and must maintain grid-connected operation to support system voltage during grid faults. However, the short-circuit current supplied by VSCs during faults can be superimposed on the short-circuit current supplied by conventional synchronous machines, potentially leading to excessive short-circuit current levels in the regional power grid, threatening the breaking capacity of circuit breakers and equipment safety.

[0003] In related technologies, a low-voltage current limiting (LVRT) strategy is commonly used to limit the short-circuit current output of the converter control system (VSC). This strategy detects the grid connection point voltage and actively limits the converter's current output when the voltage falls below a set threshold. However, existing setting methods often only consider a single fault type or a specific operating mode, failing to adequately account for boundary conditions such as changes in grid operating modes and grounding impedance. This results in overly conservative or overly aggressive initial settings. Overly conservative settings may lead to insufficient short-circuit current limiting, failing to meet system safety requirements; overly aggressive settings may trigger current limiting prematurely, weakening the VSC's voltage support capability and affecting system stability. Summary of the Invention

[0004] In view of this, the present invention discloses a method and apparatus for setting the short-circuit current control parameters of a voltage source converter, which can solve the shortcomings of related technologies.

[0005] To achieve the above objectives, the present invention discloses the following technical solution: According to a first aspect of the present invention, a method for tuning the short-circuit current control parameters of a voltage source converter is provided, comprising: Determine the short-circuit current limit control value and simulate and calculate the short-circuit current of the bus under three-phase short-circuit and single-phase ground faults in order to screen out the key bus that has a short-circuit current exceeding the short-circuit current limit control value. Perform a full-type fault scan on the key busbar to identify the key fault types that cause the short-circuit current to exceed the limit, and record the corresponding residual voltage at the first converter grid connection point; Boundary conditions of grounding impedance change and operating mode change are introduced under the critical fault mode, and the residual voltage at the second converter grid connection point when the short circuit current exceeds the limit under each boundary condition is recorded. Determine the maximum residual voltage values ​​at the grid connection points of the first and second converters, and use the sum of the preset margin and the maximum residual voltage value as the candidate start-up setting for the low-voltage current limiting strategy. If the candidate start-up setting does not exceed the upper limit of the start-up setting under the voltage support requirement constraint, the candidate start-up setting is determined as the target start-up setting.

[0006] According to a second aspect of the present invention, a device for setting short-circuit current control parameters of a voltage source converter is provided, the device comprising: Calculation unit: Determines the short-circuit current limit control value and simulates the short-circuit current of the bus under three-phase short-circuit and single-phase ground faults to screen out the key bus that has a short-circuit current exceeding the short-circuit current limit control value; First recording unit: Performs full-type fault scanning on the key bus, identifies the key fault type that causes the short-circuit current to exceed the standard, and records the corresponding residual voltage at the first converter grid connection point; Second recording unit: introduces boundary conditions of grounding impedance change and operating mode change under the critical fault mode, and records the residual voltage of the second converter grid connection point when the short circuit current exceeds the standard under each boundary condition; First determining unit: Determines the maximum residual voltage values ​​of the residual voltage at the grid connection point of the first converter and the residual voltage at the grid connection point of the second converter, and determines the sum of the preset margin and the maximum residual voltage value as the candidate start-up setting value of the low-voltage current limiting strategy; The second determining unit: if the candidate start-up setting does not exceed the upper limit of the start-up setting under the voltage support requirement constraint, the candidate start-up setting is determined as the target start-up setting.

[0007] According to a third aspect of the present invention, an electronic device is provided, comprising: processor; Memory used to store processor-executable instructions; The processor implements the steps of the method as described in the first aspect by running the executable instructions.

[0008] According to a fourth aspect of the invention, a computer-readable storage medium is provided having computer instructions stored thereon that, when executed by a processor, implement the steps of the method as described in the first aspect.

[0009] As can be seen from the above technical solutions, the method for setting the short-circuit current control parameters of the voltage source converter disclosed in this invention is as follows: On the one hand, by scanning all types of faults and introducing boundary conditions, various extreme operating conditions that may occur in actual power grid operation are considered, avoiding the problem of overly conservative or aggressive setting values ​​caused by insufficient consideration in traditional methods. On the other hand, by taking the maximum value of all residual voltages and adding a margin to set the starting setting, the short-circuit current is effectively limited even under the worst operating conditions, improving system safety. In addition, voltage support requirement constraints are introduced, balancing short-circuit current limitation and voltage support capability during the setting process, avoiding the risk of system instability due to excessive current limiting. Attached Figure Description

[0010] Figure 1 This is a flowchart of an exemplary embodiment of a method for setting short-circuit current control parameters for a voltage source converter; Figure 2 This is a schematic diagram of an exemplary embodiment of a voltage source converter to achieve low-voltage current limiting control by limiting the reactive current reference value; Figure 3 This is a schematic diagram of a short-circuit current contribution curve of a voltage source converter for short-circuit current calculation, provided in an exemplary embodiment. Figure 4 This is a schematic structural diagram of a device provided in an exemplary embodiment; Figure 5 This is a block diagram of a device for setting short-circuit current control parameters for a voltage source converter, provided in an exemplary embodiment. Detailed Implementation

[0011] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with one or more embodiments of the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of one or more embodiments of the present invention as detailed in the appended claims.

[0012] It should be noted that in other embodiments, the corresponding methods are not necessarily performed in the order shown and described in this invention. The method comprises steps. In some other embodiments, the method may include more or fewer steps than those described in this invention. Furthermore, a single step described in this invention may be broken down into multiple steps in other embodiments; and multiple steps described in this invention may be combined into a single step in other embodiments.

[0013] With the rapid development of new energy power generation and DC transmission technologies, the penetration rate of voltage source converters (VSCs) in power systems is continuously increasing. VSCs typically possess low voltage ride-through capability and must maintain grid-connected operation to support system voltage during grid faults. However, the short-circuit current supplied by VSCs during faults can be superimposed on the short-circuit current supplied by conventional synchronous machines, potentially leading to excessive short-circuit current levels in the regional power grid, threatening the breaking capacity of circuit breakers and equipment safety.

[0014] In related technologies, a low-voltage current limiting (LVRT) strategy is commonly used to limit the short-circuit current output of the converter control system (VSC). This strategy detects the grid connection point voltage and actively limits the converter's current output when the voltage falls below a set threshold. However, existing setting methods often only consider a single fault type or a specific operating mode, failing to adequately account for boundary conditions such as changes in grid operating modes and grounding impedance. This results in overly conservative or overly aggressive initial settings. Overly conservative settings may lead to insufficient short-circuit current limiting, failing to meet system safety requirements; overly aggressive settings may trigger current limiting prematurely, weakening the VSC's voltage support capability and affecting system stability.

[0015] To address the shortcomings in related technologies, this invention proposes a method and apparatus for setting the short-circuit current control parameters of a voltage source converter.

[0016] Figure 1 This is a flowchart illustrating an exemplary embodiment of a method for setting short-circuit current control parameters for a voltage source converter. For example... Figure 1 As shown, the method may include the following steps: Step 101: Determine the short-circuit current limit control value and simulate and calculate the short-circuit current of the bus under three-phase short circuit and single-phase ground fault, so as to screen out the key bus that the short-circuit current exceeds the short-circuit current limit control value.

[0017] Determine the short-circuit current limiting control value I lim Through regional power grid simulation calculations, the short-circuit current I of the busbar under three-phase short-circuit and single-phase ground faults is obtained, with I ≥ I lim The key busbars with excessive short-circuit current were selected as the criteria.

[0018] Step 102: Perform a full-type fault scan on the key busbar to identify the key fault types that cause the short-circuit current to exceed the standard, and record the corresponding residual voltage at the first converter grid connection point; Step 103: Introduce boundary conditions of grounding impedance change and operating mode change under the critical fault mode, and record the residual voltage at the second converter grid connection point when the short circuit current exceeds the standard under each boundary condition.

[0019] The full range of fault types includes three-phase short circuit, two-phase-to-ground short circuit, two-phase-to-phase short circuit, and single-phase-to-ground short circuit; the boundary conditions for changes in operating mode include topology changes caused by maintenance / outage of AC lines or transformers, and short-circuit capacity changes caused by changes in start-up mode; the boundary conditions for changes in grounding impedance include metallic grounding and grounding fault scenarios with grounding resistance.

[0020] Step 104: Determine the maximum residual voltage values ​​of the grid connection point residual voltage of the first converter and the grid connection point residual voltage of the second converter, and determine the sum of the preset margin and the maximum residual voltage value as the candidate start-up setting value of the low-voltage current limiting strategy.

[0021] Take the maximum value of the residual voltage at all grid connection points recorded in steps 102 and 103, max(Ures), and set the low-voltage current limiting strategy start-up setting Uset according to the formula Uset=max(Ures)+ΔU, where ΔU is the preset voltage start-up setting margin, i.e., the preset margin. Compare the set start-up setting Uset with the upper limit of the start-up setting Usup under the preset voltage support requirement constraint: if Uset≤Usup, then the current Uset is determined as the final start-up setting.

[0022] In one embodiment, the method further includes: if the candidate start-up setting exceeds the upper limit of the start-up setting under the voltage support requirement constraint, increasing the short-circuit current limit control value or taking voltage support auxiliary measures to re-execute the setting process. Increasing the limit control value I lim Then return to step 101 and repeat the aforementioned steps until the constraint is met, or take other voltage support auxiliary measures.

[0023] Step 105: If the candidate start-up setting does not exceed the upper limit of the start-up setting under the voltage support requirement constraint, the candidate start-up setting is determined as the target start-up setting.

[0024] In this embodiment, on the one hand, by scanning all types of faults and introducing boundary conditions, various extreme operating conditions that may occur in the actual operation of the power grid are considered, avoiding the problem of overly conservative or overly aggressive setting values ​​caused by insufficient consideration in traditional methods. On the other hand, by taking the maximum value of all residual voltages and adding a margin to set the starting setting, the short-circuit current is effectively limited even under the worst operating conditions, improving the system's safety. In addition, voltage support requirement constraints are introduced, balancing short-circuit current limitation and voltage support capability during the setting process, avoiding the risk of system instability due to excessive current limiting.

[0025] In one embodiment, the method further includes: applying the target start-up setting to the low-voltage current limiting strategy of the converter, and verifying, through regional power grid verification calculation, whether the short-circuit current of the key bus meets the limiting requirements under all types of faults.

[0026] Furthermore, the simulation calculation is based on the maximum short-circuit current contribution capability of the converter when the low-voltage current limiting strategy is not triggered, and the verification calculation is based on the short-circuit current contribution capability after the application of the low-voltage current limiting strategy.

[0027] The short-circuit current calculation during the setting of the low-voltage current limiting strategy activation setting Uset for the voltage source converter is based on the maximum short-circuit current contribution capability of the voltage source converter when the low-voltage current limiting strategy is not triggered. The short-circuit current calculation during the verification process of substituting the set Uset back into the original system is based on the short-circuit current contribution capability of the voltage source converter after applying the low-voltage current limiting strategy, wherein the activation setting of the low-voltage current limiting strategy is the setting value Uset.

[0028] Furthermore, the application of the target start-up setpoint to the low-voltage current limiting strategy of the converter includes: when the voltage detection value at the converter's grid connection point is lower than the short-circuit current limit control value, the converter enters a low-voltage current limiting mode, actively controlling the short-circuit current output by limiting the reactive current reference value; when the voltage is higher than the short-circuit current limit control value, the converter maintains normal operation mode. The short-circuit current limiting control value is set to I. lim Its value can be determined based on the equipment's short-circuit withstand capability, planning margin, and operational control objectives. When the low-voltage current-limiting start-up setting calculated under this control value may reach or exceed the upper limit of the voltage support allowable value Usup, I can be further relaxed. lim And re-iterate the adjustment, or take other voltage support auxiliary measures.

[0029] To meet the requirements of transient voltage stability, the upper limit of voltage support constraint Usup can be determined according to the power system stability calculation specifications or grid connection technical requirements. In a preferred scenario, the criterion of "the load bus voltage recovers to above 0.80pu within 10 seconds after the disturbance" can be adopted, so that the low-voltage current limiting start-up setting is not higher than 0.8pu, so as to avoid the converter station being unable to play its voltage support role in the voltage stable area due to the control strategy limitation.

[0030] To facilitate engineering implementation, this embodiment uses short-circuit current calculation software (such as PSD-SCCP) to simulate the regional power grid. The calculation can employ a voltage-level start-up strategy, a full-load start-up mode, and is not based on power flow. The bus residual voltage output from the short-circuit calculation is used as the residual voltage criterion after the fault. The residual voltage criterion can be either the positive-sequence residual voltage or the residual voltage of the faulted phase. The two criteria can be set separately to obtain the corresponding start-up settings.

[0031] In this embodiment, the low-voltage current limiting strategy of the converter is as follows: when the detected value of the converter's grid connection point voltage is lower than the setpoint Uset, the converter enters the low-voltage current limiting mode and limits the short-circuit current output; when the detected value of the grid connection point voltage is higher than the setpoint Uset, the converter maintains the normal operation mode and does not limit the short-circuit current output. During the low-voltage current limiting period, the converter achieves active control of the short-circuit current output by limiting the reactive current reference value, such as... Figure 2 As shown.

[0032] The following section takes a regional power grid connected to a flexible DC receiving-end converter station as an example to give the specific implementation steps of the method for setting the short-circuit current control parameters of the low-end voltage source converter of the converter station.

[0033] In a regional power grid connected to a flexible DC receiving-end converter station, the low-end converter H1 and high-end converter H2 are connected to different 500 kV AC system buses. Several bus nodes in the vicinity have high or excessive short-circuit current levels. Using the aforementioned short-circuit calculation settings (voltage flat start, full start, not based on power flow), the short-circuit contribution capacity of the converter station is characterized by 6 kA at one end when low-voltage current limiting is not activated and 2 kA at one end after activation. Figure 3 As shown.

[0034] The short-circuit current limit control value Ilim is determined to be Ilim = 60 kA based on the equipment's short-circuit withstand capability, planning margin, and operational control objectives. Through regional power grid simulation calculations, the short-circuit current I of the near-zone buses A, B, and C of converter H1 under three-phase short-circuit and single-phase ground fault conditions is obtained. Using I ≥ 60 kA as the criterion, it can be found that the three-phase short-circuit current of bus C exceeds the limit, as shown in Table 1. Therefore, bus C is the key bus identified as having excessive short-circuit current.

[0035] Table 1

[0036] A full range of fault types, including three-phase short circuit, two-phase-to-ground short circuit, two-phase-to-phase short circuit, and single-phase short circuit, were performed on the critical busbar C. Under each fault type, the short-circuit current I of the critical busbar was calculated through regional power grid simulation. Using I ≥ 60kA as the criterion, it was observed that the three-phase and two-phase-to-ground short-circuit currents of busbar C exceeded the standard, as shown in Table 2. Therefore, the key fault types causing the excessive short-circuit current of critical busbar C are three-phase short circuit and two-phase-to-ground short circuit.

[0037] Table 2

[0038] Under three key fault conditions—three-phase short circuit, two-phase ground fault, and single-phase short circuit—two boundary conditions—grounding impedance and grid maintenance method—the short-circuit current I of the key bus C and the positive-sequence residual voltage Ures at the converter grid connection point are obtained through regional power grid simulation calculations, as shown in Table 3.

[0039] Table 3

[0040] The maximum residual voltage at the grid connection point recorded in Table 3 when the short-circuit current exceeds the limit is max(Ures) = 0.64pu (the short-circuit circuit in the second column with a current of 0.73 is 58.1 / 57.1, which does not exceed the limit of 60kA, so it is not considered). Considering the voltage start-up setting margin ΔU = 0.06pu, the low-voltage current limiting strategy start-up setting Uset is set according to the formula Uset = max(Ures) + ΔU, i.e., Uset = 0.7pu. During the transient process after the power system is disturbed, the load bus voltage should be able to recover to above 0.80pu within 10s. Therefore, the upper limit of the start-up setting Usup under the voltage support demand constraint is set to 0.8pu. The set start-up setting Uset satisfies Uset ≤ Usup. Therefore, Uset = 0.7pu is determined as the final low-voltage current limiting strategy start-up setting of converter H1.

[0041] Following the same method, the low-voltage current limiting strategy start-up setting value of the high-end converter H2 of the converter station was set. After applying the determined start-up setting value to the low-voltage current limiting control modules of converters H1 and H2, it was re-substituted into the regional power grid simulation model including bus C for verification. During verification, the short-circuit contribution capability of each converter was characterized by 6 kA at one end without low-voltage current limiting and 2 kA at one end after starting. The verification results are shown in Table 4. It can be seen that after applying the low-voltage current limiting strategy with the set value of this invention, the current of the critical bus C under both three-phase short circuit and two-phase ground short circuit is limited to below 60kA, eliminating the risk of excessive short-circuit current and verifying the effectiveness of this method.

[0042] Table 4

[0043] Figure 4 This is a schematic structural diagram of a device provided in an exemplary embodiment. Please refer to... Figure 4At the hardware level, the device includes a processor 402, an internal bus 404, a network interface 406, memory 408, and non-volatile memory 410, and may also include other hardware required for its functions. One or more embodiments of the present invention can be implemented in software, for example, the processor 402 reads the corresponding computer program from the non-volatile memory 410 into memory 408 and then runs it. Of course, in addition to software implementation, one or more embodiments of the present invention do not exclude other implementation methods, such as logic devices or a combination of hardware and software, etc. That is to say, the execution subject of the following processing flow is not limited to each logic unit, but can also be hardware or logic devices.

[0044] Please refer to Figure 5 A device for setting short-circuit current control parameters in a voltage source converter can be applied to applications such as... Figure 5 The device shown, in order to implement the technical solution of the present invention, includes: The calculation unit 501 is used to determine the short-circuit current limit control value and to simulate and calculate the short-circuit current of the bus under three-phase short-circuit and single-phase ground faults, so as to screen out the key bus that the short-circuit current exceeds the short-circuit current limit control value. The first recording unit 502 is used to perform a full-type fault scan on the key bus, identify the key fault type that causes the short-circuit current to exceed the standard, and record the corresponding residual voltage at the first converter grid connection point. The second recording unit 503 is used to introduce boundary conditions of grounding impedance change and operating mode change under the critical fault mode, and record the residual voltage of the second converter grid connection point when the short circuit current exceeds the standard under each boundary condition. The first determining unit 504 is used to determine the maximum residual voltage values ​​of the residual voltage at the grid connection point of the first converter and the residual voltage at the grid connection point of the second converter, and to determine the sum of the preset margin and the maximum residual voltage value as the candidate start-up setting value of the low-voltage current limiting strategy. The second determining unit 505 is used to determine the candidate starting value as the target starting value when the candidate starting value does not exceed the upper limit of the starting value under the voltage support requirement constraint.

[0045] Optionally, the device further includes: The execution unit 506 is used to increase the short-circuit current limit control value or take voltage support auxiliary means to re-execute the setting process when the candidate start setting value exceeds the upper limit of the start setting value under the voltage support requirement constraint.

[0046] Optionally, the device further includes: Verification unit 507 is used to apply the target start-up setting to the low-voltage current limiting strategy of the converter, and verify whether the short-circuit current of the key bus meets the limiting requirements under all types of faults through regional power grid verification calculation.

[0047] Furthermore, the simulation calculation is based on the maximum short-circuit current contribution capability of the converter when the low-voltage current limiting strategy is not triggered, and the verification calculation is based on the short-circuit current contribution capability after the application of the low-voltage current limiting strategy. Furthermore, the verification unit 507 is specifically used for: When the voltage detection value at the converter grid connection point is lower than the short-circuit current limit control value, the converter enters the low-voltage current limiting mode and actively controls the short-circuit current output by limiting the reactive current reference value. When the voltage is higher than the short-circuit current limit control value, the converter maintains normal operation mode.

[0048] Optionally, the full range of fault types includes three-phase short circuit, two-phase-to-ground short circuit, two-phase-to-phase short circuit, and single-phase-to-ground short circuit; the boundary conditions for changes in operating mode include topology changes caused by maintenance / shutdown of AC lines or transformers, and short-circuit capacity changes caused by changes in start-up mode; the boundary conditions for changes in grounding impedance include metallic grounding and grounding fault scenarios with grounding resistance. Optionally, the criterion for determining the residual voltage at the grid connection point is either the positive sequence voltage residual voltage or the fault phase voltage residual voltage, and a setting procedure is executed for each different criterion.

[0049] The systems, devices, modules, or units described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer, which can take the form of a personal computer, laptop computer, cellular phone, camera phone, smartphone, personal digital assistant, media player, navigation device, email sending and receiving device, game console, tablet computer, wearable device, or any combination of these devices.

[0050] In a typical configuration, a computer includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0051] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0052] Computer-readable media, including both permanent and non-permanent, removable and non-removable media, can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, disk storage, quantum memory, graphene-based storage media or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0053] For any other form of computer-readable medium (or computer-readable storage medium) as described above, computer instructions may be stored thereon, which, when executed by a processor, implement one or more of the above embodiments, thereby realizing the technical solution of the present invention.

[0054] The present invention also proposes a computer program that, when executed by a processor, implements one or more of the embodiments described above, thereby realizing the technical solution of the present invention. This computer program may be specifically recorded on the above-described or other computer-readable media, and the present invention does not impose any limitations on this.

[0055] It should also be noted that 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 limitation, 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.

[0056] The foregoing has described specific embodiments of the invention. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims may be performed in a different order than that shown in the embodiments and still achieve the desired results. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0057] The terminology used in one or more embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” used in one or more embodiments of the invention and in the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0058] It should be understood that although the terms first, second, third, etc., may be used to describe various information in one or more embodiments of the present invention, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first information may also be referred to as second information without departing from the scope of one or more embodiments of the present invention, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to a determination."

[0059] The above description is merely a preferred embodiment of one or more embodiments of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments of the present invention should be included within the protection scope of one or more embodiments of the present invention.

Claims

1. A method for setting the short-circuit current control parameters of a voltage source converter, characterized in that, include: Determine the short-circuit current limit control value and simulate and calculate the short-circuit current of the bus under three-phase short-circuit and single-phase ground faults in order to screen out the key bus that has a short-circuit current exceeding the short-circuit current limit control value. Perform a full-type fault scan on the key busbar to identify the key fault types that cause the short-circuit current to exceed the limit, and record the corresponding residual voltage at the first converter grid connection point; Boundary conditions of grounding impedance change and operating mode change are introduced under the critical fault mode, and the residual voltage at the second converter grid connection point when the short circuit current exceeds the limit under each boundary condition is recorded. Determine the maximum residual voltage values ​​at the grid connection points of the first and second converters, and use the sum of the preset margin and the maximum residual voltage value as the candidate start-up setting for the low-voltage current limiting strategy. If the candidate start-up setting does not exceed the upper limit of the start-up setting under the voltage support requirement constraint, the candidate start-up setting is determined as the target start-up setting.

2. The method according to claim 1, characterized in that, The method further includes: If the candidate start-up setting exceeds the upper limit of the start-up setting under the voltage support requirement constraint, the short-circuit current limit control value is increased or voltage support auxiliary means are adopted to re-execute the setting process.

3. The method according to claim 1, characterized in that, The method further includes: The target start-up setting is applied to the low-voltage current limiting strategy of the converter. Through regional power grid verification calculations, it is verified whether the short-circuit current of the key bus meets the limiting requirements under all types of faults.

4. The method according to claim 3, characterized in that, The simulation calculation is based on the maximum short-circuit current contribution capability of the converter when the low-voltage current limiting strategy is not triggered, and the verification calculation is based on the short-circuit current contribution capability after the low-voltage current limiting strategy is applied.

5. The method according to claim 3, characterized in that, The application of the target start-up setpoint to the low-voltage current limiting strategy of the converter includes: When the voltage detection value at the converter grid connection point is lower than the short-circuit current limit control value, the converter enters the low-voltage current limiting mode and actively controls the short-circuit current output by limiting the reactive current reference value. When the voltage is higher than the short-circuit current limit control value, the converter maintains normal operation mode.

6. The method according to claim 1, characterized in that, The full range of fault types includes three-phase short circuit, two-phase-to-ground short circuit, two-phase-to-phase short circuit, and single-phase-to-ground short circuit; the boundary conditions for changes in operating mode include topology changes caused by maintenance / outage of AC lines or transformers, and short-circuit capacity changes caused by changes in start-up mode; the boundary conditions for changes in grounding impedance include metallic grounding and grounding fault scenarios with grounding resistance.

7. The method according to claim 1, characterized in that, The criterion for determining the residual voltage at the grid connection point is either the positive sequence voltage residual voltage or the fault phase voltage residual voltage, and a setting procedure is executed for each different criterion.

8. A device for setting short-circuit current control parameters for a voltage source converter, characterized in that, The device includes: Calculation unit: Determines the short-circuit current limit control value and simulates the short-circuit current of the bus under three-phase short-circuit and single-phase ground faults to screen out the key bus that has a short-circuit current exceeding the short-circuit current limit control value; First recording unit: Performs full-type fault scanning on the key bus, identifies the key fault type that causes the short-circuit current to exceed the standard, and records the corresponding residual voltage at the first converter grid connection point; Second recording unit: introduces boundary conditions of grounding impedance change and operating mode change under the critical fault mode, and records the residual voltage of the second converter grid connection point when the short circuit current exceeds the standard under each boundary condition; First determining unit: Determines the maximum residual voltage values ​​of the residual voltage at the grid connection point of the first converter and the residual voltage at the grid connection point of the second converter, and determines the sum of the preset margin and the maximum residual voltage value as the candidate start-up setting value of the low-voltage current limiting strategy; The second determining unit: if the candidate start-up setting does not exceed the upper limit of the start-up setting under the voltage support requirement constraint, the candidate start-up setting is determined as the target start-up setting.

9. An electronic device, characterized in that, include: processor; Memory used to store processor-executable instructions; The processor implements the steps of the method as described in any one of claims 1-7 by running the executable instructions.

10. A computer-readable storage medium storing computer instructions thereon, characterized in that, When executed by the processor, this instruction implements the steps of the method as described in any one of claims 1-7.

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