Fault current limiter, fault current limiter control method, computer device and medium

Abstract

This invention provides a fault current limiter, a fault current limiter control method, a computer device, and a medium. The fault current limiter includes: a main branch for providing a power flow path when the current value in the DC line is less than or equal to a preset current value; and a first commutation branch, or a second commutation branch, for transferring the current in the DC line from the main branch to a resistor current-limiting branch when the current value in the DC line is greater than the preset current value; both the first and second commutation branches contain commutation capacitors; the voltage polarity of the commutation capacitor when the first commutation branch is activated is opposite to that when the second commutation branch is activated; and a resistor current-limiting branch for providing a power flow path when the current value in the DC line is greater than the preset current value, wherein the impedance in the resistor current-limiting branch is greater than that in the main branch. This invention can handle multiple fault currents and solve the problem of reversed voltage polarity of the commutation capacitor.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of power electronics, and in particular to a fault current limiter, a fault current limiter control method, a computer device, and a medium. Background Technology

[0002] Unlike conventional DC transmission, converter stations in flexible DC transmission exhibit voltage source characteristics. When a short-circuit fault occurs at the DC pole, the fault current rises rapidly and reaches a high peak value (within milliseconds), placing extremely high demands on the operating time and reliability of the DC protection system. Fault current limiters can restrict the fault current, delay the blocking of the converter station, and buy more time for the protection system to operate effectively; they also reduce the fault current and alleviate the arc-extinguishing pressure on the DC circuit breaker. Therefore, DC fault current limiters have significant research value.

[0003] Fault current limiters based on thyristors and commutation capacitors can limit the fault current by connecting current-limiting elements (resistors, capacitors, inductors) in series with the main circuit after a fault. However, they fail to properly handle the problem of voltage polarity reversal of the commutation capacitor after the fault current limiter is triggered. This causes the fault current limiter to fail to commutate when the line experiences another fault. In other words, the fault current limiter can only limit the current for a single fault and cannot cope with multiple fault currents. Summary of the Invention

[0004] To address the issue of multiple fault currents and resolve the problem of voltage polarity reversal in the commutation capacitor, this invention proposes a fault current limiter, a fault current limiter control method, a computer device, and a medium.

[0005] In a first aspect, the present invention provides a fault current limiter, comprising: a main branch, a first commutation branch, a second commutation branch, and a resistor current limiting branch;

[0006] The main branch is used to provide a path for electrical energy flow when the current value in the DC line is less than or equal to a preset current value.

[0007] When the current value in the DC line is greater than the preset current value, the first commutation branch or the second commutation branch is used to transfer the current in the DC line from the main branch to the resistor current limiting branch; both the first commutation branch and the second commutation branch contain commutation capacitors; when the first commutation branch is turned on, the voltage polarity of the commutation capacitor is opposite to that when the second commutation branch is turned on.

[0008] A resistor-limiting current branch is used to provide a path for electrical energy flow when the current value in the DC line is greater than a preset current value. The impedance in the resistor-limiting current branch is greater than the impedance in the main branch.

[0009] Considering that existing fault current limiters based on thyristors and commutation capacitors experience voltage polarity reversal in the commutation capacitor after triggering, leading to commutation failure during subsequent faults and an inability to handle multiple fault currents, the fault current limiter provided in this invention addresses this issue. It incorporates a first commutation branch and a second commutation branch. When the voltage polarity of the commutation capacitor differs, different commutation branches are activated. Even if the voltage polarity of the commutation capacitor reverses after handling one fault current, the corresponding commutation branch can still be activated during subsequent fault currents, diverting current from the main branch to the resistor-limiting branch in the DC line. This allows the fault current limiter to handle multiple fault currents and solves the problem of commutation capacitor voltage polarity reversal. Furthermore, the fault current limiter provided in this invention has a simplified structure, reducing its cost.

[0010] In conjunction with the first aspect, in the first embodiment of the first aspect, the main branch includes a thyristor;

[0011] The anode of the thyristor is connected to the input terminal of the fault current limiter;

[0012] The cathode of the thyristor is connected to the output terminal of the fault current limiter.

[0013] In conjunction with the first embodiment of the first aspect, in the second embodiment of the first aspect, the main branch further includes a first diode;

[0014] The cathode of the first diode is connected to the anode of the thyristor, and the anode of the first diode is connected to the cathode of the thyristor.

[0015] The first phase-changing branch also includes the first upper bridge arm and the first lower bridge arm;

[0016] The anode of the first upper bridge arm is connected to the input terminal of the fault current limiter, and the cathode of the first upper bridge arm is connected to the first port of the commutation capacitor.

[0017] The anode of the first lower bridge arm is connected to the second port of the commutation capacitor, and the cathode of the first lower bridge arm is connected to the output terminal of the fault current limiter.

[0018] In conjunction with the second embodiment of the first aspect, in the third embodiment of the first aspect, the second commutation branch further includes a second upper bridge arm and a second lower bridge arm;

[0019] The cathode of the second upper bridge arm is connected to the output terminal of the fault current limiter, and the anode of the second upper bridge arm is connected to the first port of the commutation capacitor.

[0020] The cathode of the second lower bridge arm is connected to the second port of the commutation capacitor, and the anode of the second lower bridge arm is connected to the input terminal of the fault current limiter.

[0021] In conjunction with the third embodiment of the first aspect, in the fourth embodiment of the first aspect, a first energy-consuming element is connected between the output terminal of the fault current limiter and the cathode of the first lower bridge arm;

[0022] A second energy-consuming element is connected between the output of the fault current limiter and the cathode of the second upper bridge arm.

[0023] In conjunction with the first aspect or the fourth embodiment of the first aspect, in the fifth embodiment of the first aspect, the resistor current-limiting branch includes a third energy-consuming element and a second diode;

[0024] The anode of the second diode is connected to the input terminal of the fault current limiter;

[0025] The cathode of the second diode is connected to one end of the third energy-consuming element;

[0026] The other end of the third energy-consuming element is connected to the output of the fault current limiter.

[0027] In a second aspect, the present invention also provides a fault current limiter control method for the fault current limiter in the first aspect or any embodiment of the first aspect, the method comprising:

[0028] Obtain the current value in a DC line;

[0029] When the current value is greater than the preset current value, obtain the current voltage polarity of the commutation capacitor;

[0030] Based on the current voltage polarity, determine the effective commutation branch, which is either the first commutation branch or the second commutation branch.

[0031] The effective commutation branch is opened, causing the commutation capacitor to release current, and the main branch is turned off by the current released by the commutation capacitor.

[0032] Until the polarity of the commutation capacitor voltage changes, and the voltage value of the commutation capacitor equals the preset voltage value, the effective commutation branch is turned off, allowing the current in the DC line to flow to the resistor current-limiting branch.

[0033] Considering that existing fault current limiters based on thyristors and commutation capacitors experience voltage polarity reversal in the commutation capacitor after triggering, causing commutation failure and inability to handle multiple fault currents during subsequent faults, the fault current limiter control method provided in this invention sets up a first commutation branch and a second commutation branch in the fault current limiter. When the voltage polarity of the commutation capacitor is different, different commutation branches are activated. Even if the voltage polarity of the commutation capacitor reverses after handling one fault current, the corresponding commutation branch can still be activated when the next fault current arrives, allowing the current in the DC line to transfer from the main branch to the resistor current-limiting branch. This enables the fault current limiter to handle multiple fault currents and solves the problem of commutation capacitor voltage polarity reversal.

[0034] In conjunction with the second aspect, in the first embodiment of the second aspect, before the step of obtaining the current value on the DC line, the method further includes:

[0035] Precharge the commutation capacitor until its voltage value equals the preset voltage value.

[0036] Thirdly, the present invention also provides a computer device, including a memory and a processor, which are communicatively connected to each other. The memory stores computer instructions, and the processor executes the computer instructions to perform the steps of the fault current limiter control method of the second aspect or the first embodiment of the second aspect.

[0037] Fourthly, the present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the fault current limiter control method of the second aspect or the first embodiment of the second aspect. Attached Figure Description

[0038] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0039] Figure 1 This is a circuit diagram of a fault current limiter according to an exemplary embodiment;

[0040] Figure 2 This is a flowchart illustrating a fault current limiter control method according to an exemplary embodiment.

[0041] Figure 3 This is an example of the current flow path diagram in the fault current limiter when the current value in the DC line is less than or equal to the preset current value.

[0042] Figure 4 In one example, when the current value in the DC line is greater than the preset current value, the current flow path diagram in the first commutation branch 2 of the fault current limiter is shown.

[0043] Figure 5 In one example, when the current value in the DC line is greater than the preset current value, the current flow path diagram in the second commutation branch 3 of the fault current limiter is shown.

[0044] Figure 6In one example, when the current value in the DC line is greater than the preset current value, the current flow path diagram in the fault current limiter resistor current limiting branch 4 is shown.

[0045] Figure 7 This is a schematic diagram of the hardware structure of a computer device according to an exemplary embodiment. Detailed Implementation

[0046] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0048] To address the issue of multiple fault currents and resolve the problem of voltage polarity reversal in the commutation capacitor, this invention proposes a fault current limiter, a fault current limiter control method, a computer device, and a medium.

[0049] Figure 1 This is a circuit diagram of a fault current limiter according to an exemplary embodiment. For example... Figure 1 As shown, the fault current limiter includes: main branch 1, first commutation branch 2, second commutation branch 3, and resistor current limiting branch 4.

[0050] Main branch 1 is used to provide a path for electrical energy flow when the current value in the DC line is less than or equal to a preset current value.

[0051] In an optional embodiment, the preset current value can be set according to the needs of the DC line, and no specific limitation is made here.

[0052] When the current value in the DC line is greater than the preset current value, the first commutation branch 2 or the second commutation branch 3 is used to transfer the current in the DC line from the main branch 1 to the resistor current limiting branch 4; both the first commutation branch 2 and the second commutation branch 3 contain commutation capacitors; when the first commutation branch 2 is turned on, the voltage polarity of the commutation capacitor C is opposite to that when the second commutation branch 3 is turned on.

[0053] In one optional embodiment, different voltage polarities of the commutation capacitor C result in different effective commutation branches being activated. Based on the current voltage polarity of the commutation capacitor C, the effective commutation branch is determined, namely, the first commutation branch 2, or the second commutation branch 3. The current released by the commutation capacitor C shuts off the main branch 1, transferring the current from the main branch 1 to the resistor-limited current branch 4.

[0054] In an optional embodiment, the first commutation branch 2 includes an upper bridge arm and a lower bridge arm in addition to the commutation capacitor C. The bridge arm can be composed of at least one fully controlled device connected in series and parallel, or it can be composed of at least one semi-controlled device connected in series and parallel. The number of fully controlled devices and the number of semi-controlled devices can be determined according to actual needs and are not specifically limited here.

[0055] In an optional embodiment, the second commutation branch 3, in addition to the commutation capacitor C, also includes an upper bridge arm and a lower bridge arm. The bridge arm can be composed of at least one fully controlled device connected in series and parallel, or it can be composed of at least one semi-controlled device connected in series and parallel. The number of fully controlled devices and the number of semi-controlled devices can be determined according to actual needs, and no specific limitation is made here.

[0056] In one optional embodiment, the voltage polarity of the commutation capacitor C includes two cases: the first port is negative and the second port is positive, and the first port is positive and the second port is negative.

[0057] The current-limiting resistor branch 4 is used to provide a path for electrical energy flow when the current value in the DC line is greater than the preset current value. The impedance in the current-limiting resistor branch 4 is greater than the impedance in the main branch 1.

[0058] Considering that existing fault current limiters based on thyristors and commutation capacitors experience voltage polarity reversal in the commutation capacitor after triggering, causing commutation failure during subsequent faults and making them unable to handle multiple fault currents, the fault current limiter provided in this embodiment of the invention incorporates a first commutation branch 2 and a second commutation branch 3. When the voltage polarity of the commutation capacitor C is different, different commutation branches are activated. Even if the voltage polarity of the commutation capacitor C reverses after handling one fault current, the corresponding commutation branch can still be activated when the next fault current arrives, diverting the current in the DC line from the main branch 1 to the resistor current-limiting branch 4. This allows the fault current limiter to handle multiple fault currents and solves the problem of voltage polarity reversal in the commutation capacitor C. Furthermore, the fault current limiter provided in this embodiment of the invention has a simplified structure, saving on the cost of fault current limiters.

[0059] exist Figure 1 In the circuit, the main branch 1 includes a thyristor S1; the anode of the thyristor S1 is connected to the input terminal P1 of the fault current limiter; the cathode of the thyristor S1 is connected to the output terminal P2 of the fault current limiter.

[0060] The main branch 1 also includes a first diode D1; the cathode of the first diode D1 is connected to the anode of the thyristor S1, and the anode of the first diode D1 is connected to the cathode of the thyristor S1.

[0061] In addition to the commutation capacitor C, the first commutation branch 2 also includes a first upper bridge arm S2 and a first lower bridge arm S5; the anode of the first upper bridge arm S2 is connected to the input terminal P1 of the fault current limiter, and the cathode of the first upper bridge arm S2 is connected to the first port of the commutation capacitor C; the anode of the first lower bridge arm S5 is connected to the second port of the commutation capacitor C, and the cathode of the first lower bridge arm S5 is connected to the output terminal P2 of the fault current limiter.

[0062] In addition to the commutation capacitor C, the second commutation branch 3 also includes a second upper bridge arm S3 and a second lower bridge arm S4; the cathode of the second upper bridge arm S3 is connected to the output terminal P2 of the fault current limiter, and the anode of the second upper bridge arm S3 is connected to the first port of the commutation capacitor C; the cathode of the second lower bridge arm S4 is connected to the second port of the commutation capacitor C, and the anode of the second lower bridge arm S4 is connected to the input terminal P1 of the fault current limiter.

[0063] In one optional embodiment, different voltage polarities of the commutation capacitor C result in different activated effective commutation branches. When the first port of the commutation capacitor C is negative and the second port is positive, the first commutation branch 2 is activated, i.e., the devices in the first upper bridge arm S2 and the first lower bridge arm S5 of the first commutation branch 2 are activated; when the first port of the commutation capacitor C is positive and the second port is negative, the second commutation branch 3 is activated, i.e., the devices in the second lower bridge arm S4 and the second upper bridge arm S3 of the second commutation branch 3 are activated. Then, the main branch 1 is turned off by the discharge current of the commutation capacitor C until the voltage polarity of the commutation capacitor C changes and the voltage value of the commutation capacitor C equals the preset voltage value, thus turning off the effective commutation branch and allowing the current in the DC line to flow to the resistor current-limiting branch 4, realizing the commutation process of the fault current.

[0064] exist Figure 1 In this circuit, a first energy-consuming element is connected between the output terminal P2 of the fault current limiter and the cathode of the first lower bridge arm S5; a second energy-consuming element is connected between the output terminal P2 of the fault current limiter and the cathode S3 of the second upper bridge arm. For example, the energy-consuming element can be a resistor, inductor, or other energy-consuming element.

[0065] In an optional embodiment, the first energy-consuming element and the second energy-consuming element can be the same resistor R1, such as... Figure 1 As shown.

[0066] In an optional embodiment, the resistor-limiting current branch 4 includes a third energy-consuming element R2 and a second diode D2; the anode of the second diode D2 is connected to the input terminal P1 of the fault current limiter; the cathode of the second diode D2 is connected to one end of the third energy-consuming element; and the other end of the third energy-consuming element R2 is connected to the output terminal P2 of the fault current limiter. By increasing the impedance in the DC line through the energy-consuming element, the fault current is reduced, thereby achieving the current-limiting function of the fault current limiter.

[0067] In an optional embodiment, the number of the third energy-consuming element R2 can be set according to actual needs, and no specific limitation is made here.

[0068] Figure 2 This is a flowchart illustrating a fault current limiter control method according to an exemplary embodiment, used for the aforementioned fault current limiter. The method includes the following steps S101 to S105:

[0069] Step S101: Obtain the current value of the DC line.

[0070] Step S102: When the current value is greater than the preset current value, obtain the current voltage polarity of the commutation capacitor.

[0071] Step S103: Based on the current voltage polarity, determine the effective commutation branch, which is either the first commutation branch 2 or the second commutation branch 3.

[0072] Step S104: Open the effective commutation branch, so that the commutation capacitor releases current, and the main branch 1 is turned off by the current released by the commutation capacitor C.

[0073] Step S105: Until the polarity of the commutation capacitor C changes and the voltage value of the commutation capacitor is equal to the preset voltage value, the effective commutation branch is turned off, so that the current in the DC line flows to the resistor current limiting branch 4.

[0074] Considering that existing fault current limiters based on thyristors and commutation capacitors experience voltage polarity reversal in the commutation capacitor after triggering, causing commutation failure and inability to handle multiple fault currents during subsequent faults, the fault current limiter control method provided in this invention employs a fault current limiter including a first commutation branch 2 and a second commutation branch 3. When the voltage polarity of the commutation capacitor is different, different commutation branches are activated. Even if the voltage polarity of the commutation capacitor C reverses after handling one fault current, the corresponding commutation branch can still be activated when the next fault current arrives, allowing the current in the DC line to transfer from the main branch 1 to the resistor current limiting branch 4. This enables the fault current limiter to handle multiple fault currents and solves the problem of voltage polarity reversal in the commutation capacitor C.

[0075] In one example, prior to step S101 above, the method further includes: pre-charging the commutation capacitor until the voltage value of the commutation capacitor is equal to a preset voltage value.

[0076] In an optional embodiment, when the commutation branch includes a thyristor, the preset voltage value needs to meet the following conditions: when a forward discharge voltage is applied to the thyristor in the commutation branch, it can be turned on by applying a trigger pulse, and the discharge current of the commutation capacitor C can force the forward conduction current of the thyristor S1 in the main branch 1 to decrease to the maintenance current for a period of time, thereby forcing the thyristor S1 to turn off.

[0077] Figure 3 This is a flow path diagram of the current in the fault current limiter when the current value in the DC line is less than or equal to the preset current value. When the current value in the DC line is less than or equal to the preset current value, the DC line is considered to be in normal operation. A trigger pulse is given to the thyristor S1, the main branch 1 is turned on, and the current in the DC line flows in from the input terminal P1 of the fault current limiter, passes through the thyristor S1 in the main branch 1 of the fault current limiter, and flows out from the output terminal P2 of the fault current limiter.

[0078] Figure 4 This is the current flow path diagram in the first commutation branch 2 of the fault current limiter when the current value in the DC line is greater than the preset current value. When the detected current value is greater than the preset current value, it is considered that there is a fault current in the DC line. When the first port of the commutation capacitor C is negative and the second port is positive, a signal is given to the fully controlled device in the first upper bridge arm S2 in the first commutation branch 2 to turn on, and the thyristor in the first lower bridge arm S5 is triggered by a pulse. At this time, the commutation capacitor C begins to discharge, and the current gradually transfers from the main branch 1 (P1→S1→P2) to the first commutation branch 2 (P1→S2→C→S5→R1→P2). When the positive current flowing through the thyristor S1 is less than the holding current for a period of time, the thyristor S1 is turned off. At this time, the current released by the commutation capacitor C will flow through the first diode D1 in the main branch 1. The components through which the current released by the commutation capacitor C flows are, in sequence, the second port of C → S5 → R1 → D1 → S2 → the first port of C. The direction of current flow in the DC line is P1 → S2 → C → S5 → R1 → P2.

[0079] Figure 5This is the current flow path diagram in the second commutation branch 3 of the fault current limiter when the current value in the DC line is greater than the preset current value. When the detected current value is greater than the preset current value, and the first port of the commutation capacitor C is positive and the second port is negative, a signal is given to the fully controlled device in the second lower bridge arm S4 in the second commutation branch 3 to turn on, and the thyristor in the second upper bridge arm S3 is triggered by a pulse. At this time, the commutation capacitor C begins to discharge, and the current gradually transfers from the main branch 1 (P1→S1→P2) to the second commutation branch 3 (P1→S4→C→S3→R1→P2). When the positive current flowing through the thyristor in S1 is less than the holding current for a period of time, the thyristor S1 is turned off. At this time, the current released by the commutation capacitor C will flow through the first diode D1 in the main branch 1. The components through which the current released by the commutation capacitor C flows are, in sequence, the first port of C → S3 → R1 → D1 → S4 → the second port of C. The direction of current flow in the DC line is P1 → S4 → C → S3 → R1 → P2.

[0080] Figure 6 This is a flow path diagram of the current in the fault current limiter resistor current limiting branch 4 when the current value in the DC line is greater than the preset current value. When the current value in the DC line is greater than the preset current value, the commutation capacitor C discharges until the voltage polarity changes, and when the voltage value of the commutation capacitor C is equal to the preset voltage value, the effective commutation branch is turned off, allowing the current in the DC line to flow to the resistor current limiting branch 4.

[0081] Figure 7 This is a schematic diagram of the hardware structure of a computer device according to an exemplary embodiment. For example... Figure 7 As shown, the device includes one or more processors 710 and a memory 720, the memory 720 including persistent memory, volatile memory, and a hard disk. Figure 7 Taking a processor 710 as an example, the device may also include an input device 730 and an output device 740.

[0082] The processor 710, memory 720, input device 730, and output device 740 can be connected via a bus or other means. Figure 7 Taking the example of a connection between China and Israel via a bus.

[0083] Processor 710 can be a Central Processing Unit (CPU). Processor 710 can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or combinations thereof. The general-purpose processor can be a microprocessor or any conventional processor.

[0084] The memory 720, as a non-transitory computer-readable storage medium, includes persistent memory, volatile memory, and a hard disk. It can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the program instructions / modules corresponding to the fault current limiter control method in this embodiment. The processor 710 executes various server functions and data processing by running the non-transitory software programs, instructions, and modules stored in the memory 720, thereby implementing any of the above-mentioned fault current limiter control methods.

[0085] The memory 720 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data that is needed and required. Furthermore, the memory 720 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 720 may optionally include memory remotely located relative to the processor 710, and these remote memories can be connected to the data processing device via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0086] Input device 730 can receive input digital or character information, and generate signal inputs related to user settings and function control. Output device 740 may include display devices such as a display screen.

[0087] One or more modules are stored in memory 720, and when executed by one or more processors 710, they perform actions such as... Figure 2 The method shown.

[0088] The above-described product can execute the method provided in the embodiments of the present invention, and has the corresponding functional modules and beneficial effects for executing the method. Technical details not described in detail in this embodiment can be found in [reference 1]. Figure 2 The relevant descriptions in the illustrated embodiments.

[0089] This invention also provides a non-transitory computer storage medium storing computer-executable instructions that can execute the control methods described in any of the above-described method embodiments. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk drive (HDD), or solid-state drive (SSD), etc.; the storage medium may also include combinations of the above types of memory.

[0090] It should be noted that, in this document, relational terms such as "first" and "second" are used merely 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. Unless otherwise specified, 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 the element.

[0091] The above are merely specific embodiments of the present invention, enabling those skilled in the art to understand or implement the invention. 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 the invention. Therefore, the present invention 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 claimed herein.

Claims

1. A fault current limiter, characterized by The fault current limiter comprises a main branch, a first commutation branch, a second commutation branch and a resistance current limiting branch; The main branch is configured to provide an electric energy flow path when a current value of a current in a DC line is less than or equal to a preset current value; When the current value of the current in the DC line is greater than the preset current value, the first commutation branch or the second commutation branch is configured to serve as an effective commutation branch to transfer the current in the DC line from the main branch to the resistance current limiting branch; the first commutation branch and the second commutation branch each comprise a commutation capacitor; a voltage polarity of the commutation capacitor when the first commutation branch is turned on is opposite to a voltage polarity of the commutation capacitor when the second commutation branch is turned on; wherein the effective commutation branch is determined according to a current voltage polarity of the commutation capacitor, and the effective commutation branch is configured to cause the commutation capacitor to release a current when the effective commutation branch is turned on, and the current released by the commutation capacitor is configured to turn off the main branch; The resistance current limiting branch is configured to provide an electric energy flow path when the current value of the current in the DC line is greater than the preset current value, and an impedance in the resistance current limiting branch is greater than an impedance in the main branch; The main branch comprises a thyristor; An anode of the thyristor is connected to an input end of the fault current limiter; A cathode of the thyristor is connected to an output end of the fault current limiter; The main branch further comprises a first diode; A cathode of the first diode is connected to an anode of the thyristor, and an anode of the first diode is connected to a cathode of the thyristor; The first commutation branch further comprises a first upper bridge arm and a first lower bridge arm; An anode of the first upper bridge arm is connected to the input end of the fault current limiter, and a cathode of the first upper bridge arm is connected to a first port of the commutation capacitor; An anode of the first lower bridge arm is connected to a second port of the commutation capacitor, and a cathode of the first lower bridge arm is connected to the output end of the fault current limiter; The second commutation branch further comprises a second upper bridge arm and a second lower bridge arm; A cathode of the second upper bridge arm is connected to the output end of the fault current limiter, and an anode of the second upper bridge arm is connected to the first port of the commutation capacitor; A cathode of the second lower bridge arm is connected to the second port of the commutation capacitor, and an anode of the second lower bridge arm is connected to the input end of the fault current limiter.

2. The fault current limiter according to claim 1, wherein a first energy consumption element is connected between the output end of the fault current limiter and the cathode of the first lower bridge arm; and a second energy consumption element is connected between the output end of the fault current limiter and the cathode of the second upper bridge arm.

3. The fault current limiter according to claim 1 or 2, wherein the resistance current limiting branch comprises a third energy consumption element and a second diode; an anode of the second diode is connected to the input end of the fault current limiter; a cathode of the second diode is connected to one end of the third energy consumption element; and the other end of the third energy consumption element is connected to the output end of the fault current limiter. The method for the fault current limiter according to any one of claims 1 to 3 comprises: ​ ​ ​ ​ ​ 4. A fault current limiter control method characterized by, ​ obtaining a current value of the current in the DC line; when the current value is greater than a preset current value, obtaining a current voltage polarity of the commutation capacitor; determining an effective commutation branch according to the current voltage polarity, the effective commutation branch being a first commutation branch or a second commutation branch; turning on the effective commutation branch, so that the commutation capacitor releases current, and the current released by the commutation capacitor turns off the main branch; until the capacitor voltage polarity of the commutation capacitor changes, and the voltage value of the commutation capacitor is equal to a preset voltage value, the effective commutation branch is turned off, so that the current in the DC line flows to the resistance current limiting branch.

5. The method of claim 4, wherein, Before the step of obtaining the current value on the DC line, the method further comprises: pre-charging the commutation capacitor until the voltage value of the commutation capacitor is equal to a preset voltage value.

6. A computer device, comprising: The controller comprises a memory and a processor, the memory and the processor are in communication connection with each other, the memory stores computer instructions, and the processor executes the computer instructions to perform the steps of the fault current limiter control method according to any one of claims 4-5.

Images