Current shutoff device and control method thereof

Abstract

The present application provides a current shutoff device and a control method thereof. The current shutoff device includes: a first flow branch, including at least two groups of mechanical switches and nonlinear resistors connected in parallel and connected in series; a second flow branch; a first transfer branch; a second transfer branch; an energy-consuming branch, including a nonlinear resistor, or at least two nonlinear resistors connected in series, wherein the first flow branch is connected in series with the first transfer branch to form a first bridge arm, the second flow branch is connected in series with the energy-consuming branch to form a second bridge arm, and the first bridge arm, the second bridge arm, and the second transfer branch are connected in parallel; a reactor unit and a self-excitation module unit, connected in series in a parallel loop of the first bridge arm and the second transfer branch, the reactor unit being connected in series inside the first flow branch, inside the first transfer branch, or inside the second transfer branch, and the self-excitation module unit being connected in series inside the first flow branch, inside the first transfer branch, or inside the second transfer branch.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a current shutoff device and a control method thereof. Background Art

[0002] In DC power system applications, due to the rapid increase in fault current, rapid and reliable fault isolation and restoration are critical to ensuring stable operation of the DC power system. Currently, DC circuit breakers on the market primarily include mechanical DC circuit breakers, hybrid DC circuit breakers, and all-solid-state DC circuit breakers. Mechanical DC circuit breakers are further categorized as employing either passive or active oscillation technology. However, because mechanical DC circuit breakers utilize large-capacity capacitors, they present significant challenges such as bulky equipment, long shutdown times for low currents, a high risk of restrike, and a tendency to induce system oscillations. These issues pose a potential risk to the normal operation of the power system and other equipment.

[0003] Hybrid DC circuit breakers combine mechanical switches with power electronics to achieve current-controlled shutdown, offering arc-free, fast closing, and strong applicability. However, the current-cutting performance and economic efficiency of hybrid DC circuit breakers are limited by fully controlled power electronics, restricting their widespread application in HVDC transmission systems.

[0004] Existing patent CN108475595A proposes a DC circuit breaker based on the LC active resonance principle. This device addresses some of the shortcomings of existing technologies, such as high risk of mechanical reignition, long shutdown time at low currents, significant oscillation, and high equipment costs. However, it still has shortcomings in closing / reclosing operations, requiring the addition of an additional discharge circuit or requiring the mechanical switch to withstand large inrush currents.

[0005] The above information disclosed in this Background section is only for enhancement of understanding of the background of the application and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the Invention

[0006] In order to solve at least one of the above problems, the present application proposes a current shutoff device and a control method thereof.

[0007] According to a first aspect of the present application, at least one embodiment of the present application provides a current shutoff device, comprising: a first flow branch, the first flow branch comprising at least two groups of mechanical switches and nonlinear resistors connected in parallel and connected in series; a second flow branch, the second flow branch comprising a mechanical switch or at least two mechanical switches connected in series; a first transfer branch; a second transfer branch, the second transfer branch comprising a capacitor or at least two capacitors connected in series; an energy consumption branch, the energy consumption branch comprising a nonlinear resistor or at least two nonlinear resistors connected in series, wherein the first flow branch is connected in series with the first transfer branch to form a first bridge arm, and the first flow branch is connected in series with the first transfer branch to form a first bridge arm. The midpoint of the series connection of the first transfer branch is the first port of the current shut-off device, the second flow branch is connected in series with the energy consumption branch to form a second bridge arm, the midpoint of the series connection of the second flow branch and the energy consumption branch is the second port of the current shut-off device, the first bridge arm, the second bridge arm and the second transfer branch are connected in parallel; the reactor unit and the self-excitation module unit are connected in series in the parallel loop of the first bridge arm and the second transfer branch, the reactor unit is connected in series inside the first flow branch, the first transfer branch or the second transfer branch, and the self-excitation module unit is connected in series inside the first flow branch, the first transfer branch or the second transfer branch.

[0008] For example, in some embodiments of the present application, when the reactor unit is connected in series inside the first current branch, the reactor unit includes a saturable reactor for limiting the current change rate of the mechanical switch current in the first current branch at the moment of zero crossing.

[0009] For example, in some embodiments of the present application, the first flow branch further includes a saturable inductor, which is connected in series with the mechanical switch in the first flow branch, and is used to limit the current change rate of the mechanical switch in the first flow branch at the moment when the current passes through zero.

[0010] For example, in some embodiments of the present application, the second flow branch further includes a saturable inductor, which is connected in series with the mechanical switch in the second flow branch, and is used to limit the current change rate of the mechanical switch in the second flow branch at the moment when the current passes through zero.

[0011] For example, in some embodiments of the present application, the self-excitation module is a half-bridge structure, including a first power electronic switch, a second power electronic switch and a first voltage source, the positive pole of the first power electronic switch is connected to the positive pole of the first voltage source, the negative pole of the first power electronic switch is connected to the positive pole of the second power electronic switch and then leads to an external wiring, and the negative pole of the second power electronic switch is connected to the negative pole of the first voltage source and then leads to an external wiring; or the self-excitation module is a full-bridge structure, including a third power electronic switch, a fourth power electronic switch, a fifth power electronic switch, a sixth power electronic switch and a second voltage source, the positive pole of the third power electronic switch is connected to the positive pole of the fifth power electronic switch and the positive pole of the second voltage source respectively, and the negative pole of the fourth power electronic switch is connected to the positive pole of the fifth power electronic switch and the positive pole of the second voltage source respectively. The self-excitation module is connected to the negative electrode of the sixth power electronic switch and the negative electrode of the second voltage source, the negative electrode of the third power electronic switch is connected to the positive electrode of the fourth power electronic switch and then leads to an external wire, and the negative electrode of the fifth power electronic switch is connected to the positive electrode of the sixth power electronic switch and then leads to an external wire; or the self-excitation module is a half-bridge structure, including a seventh power electronic switch, an eighth power electronic switch, a third voltage source and a fourth voltage source, the positive electrode of the seventh power electronic switch is connected to the positive electrode of the third voltage source, the negative electrode of the eighth power electronic switch is connected to the negative electrode of the fourth voltage source, the negative electrode of the seventh power electronic switch is connected to the positive electrode of the eighth power electronic switch and then leads to an external wire, and the negative electrode of the third voltage source is connected to the positive electrode of the fourth voltage source and then leads to an external wire.

[0012] For example, in some embodiments of the present application, the first power electronic switch, the second power electronic switch, the third power electronic switch, the fourth power electronic switch, the fifth power electronic switch, the sixth power electronic switch, the seventh power electronic switch and the eighth power electronic switch include a first-level power semiconductor device, or at least two-level power semiconductor devices connected in series or parallel, wherein: the power semiconductor device includes a fully controlled power semiconductor device or a half-controlled power semiconductor device.

[0013] For example, in some embodiments of the present application, the fully-controlled power semiconductor device includes at least one of an IGBT, an IEGT, an IGCT, a MOSFET, and a GTO; and the half-controlled power semiconductor device includes a thyristor.

[0014] For example, in some embodiments of the present application, the first voltage source, the second voltage source, the third voltage source and the fourth voltage source include at least one of a pre-charged capacitor, an energy storage battery and an AC rectifier power supply.

[0015] According to a second aspect of the present application, at least one embodiment of the present application provides a method for controlling a current interruption device as described in any one of the first aspects, comprising:

[0016] a. In the event of a power system failure, outputting a tripping command to disconnect the mechanical switches of the first flow branch and the second flow branch;

[0017] b. When the mechanical switches of the first and second current-passing branches are separated to the insulation-open position, triggering the self-excitation module unit to output a single-pulse or multi-pulse square wave voltage to excite the capacitor of the second transfer branch and the reactor of the reactor unit to oscillate, generating an oscillating current with an amplitude equal to and a direction opposite to the fault current, wherein the oscillating current causes the mechanical switch of the first current-passing branch to turn off through zero crossing;

[0018] c. In response to the mechanical switch of the first current-carrying branch being turned off at zero crossing, the fault current charges the capacitor of the second transfer branch. When the voltage across the capacitor is greater than the operating voltage of the nonlinear resistor of the energy-consuming branch, the fault current is transferred to the energy-consuming branch, causing the mechanical switch of the second current-carrying branch to be turned off at zero crossing, and the fault current is dissipated to zero through the energy-consuming branch.

[0019] d. When the fault current dissipates to zero, closing the mechanical switches of the first flow-through branches in groups one by one, so that the capacitor of the second transfer branch discharges through the nonlinear resistor of the first flow-through branch;

[0020] e. Outputting a reclosing command to close the mechanical switch of the second flow branch;

[0021] f. When the current interruption device is reclosed to the faulty power system, re-execute step a.

[0022] For example, in some embodiments of the present application, the further step includes: when no fault occurs in the power system, the mechanical switches of the first flow branch and the second flow branch are in a closed state.

[0023] The present application provides a current shut-off device and a control method thereof, a current shut-off device and a control method thereof, when the current shut-off device is tripped, by controlling the operating states of the internal components of the flow branch and the transfer branch, the transfer branch generates an oscillating current with an amplitude equal to and a direction opposite to the fault current, thereby reliably shutting off the flow branch, overcoming the problems of high risk of reignition of mechanical switches, long shutdown time for small currents, significant oscillation with the power system, and high equipment cost, and is conducive to large-scale promotion and application in AC and DC power transmission and distribution systems; by closing multiple groups of mechanical switches in the flow branch one by one, the energy release of the capacitor during the last tripping operation is realized, effectively reducing the size of the closing / reclosing inrush current and improving the life of the mechanical switch.

[0024] It should be understood that the foregoing general description and the following detailed description are merely illustrative and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] By describing in detail exemplary embodiments thereof with reference to the accompanying drawings, the above and other objects, features and advantages of the present application will become more apparent. The drawings described below are only some embodiments of the present application, and are not intended to limit the present application.

[0026] Figure 1 A first embodiment of a circuit structure diagram showing an exemplary current interruption device;

[0027] Figure 2 A second embodiment of a circuit structure diagram showing an exemplary current interruption device;

[0028] Figure 3 A third embodiment showing a circuit structure diagram of an exemplary current interruption device;

[0029] Figure 4 A fourth embodiment showing a circuit structure diagram of an exemplary current interruption device;

[0030] Figure 5 A fifth embodiment showing a circuit structure diagram of an exemplary current interruption device;

[0031] Figure 6 A sixth embodiment showing a circuit structure diagram of an exemplary current interruption device;

[0032] Figure 7 A seventh embodiment of a circuit diagram showing an exemplary current interruption device;

[0033] Figure 8 An eighth embodiment showing a circuit structure diagram of an exemplary current interruption device;

[0034] Figure 9 A ninth embodiment of a circuit diagram showing an exemplary current interruption device;

[0035] Figure 10A A first embodiment of a circuit structure diagram of an exemplary self-excitation module is shown;

[0036] Figure 10B A second embodiment of a circuit structure diagram of an exemplary self-excitation module is shown;

[0037] Figure 10C A third embodiment of a circuit structure diagram of an exemplary self-excitation module is shown;

[0038] Figure 11 A flow chart showing an exemplary method for controlling a current interruption device;

[0039] Figure 12 An embodiment of an expanded connection diagram of an exemplary current disconnect device is shown. DETAILED DESCRIPTION

[0040] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art. Like reference numerals in the drawings represent like or similar parts, and thus repetitive description thereof will be omitted.

[0041] The described features, structures or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced without one or more of these specific details, or other methods, components, materials, devices, etc. may be employed. In these cases, well-known structures, methods, devices, implementations, materials or operations will not be shown or described in detail.

[0042] The flowcharts shown in the accompanying drawings are for illustrative purposes only and do not necessarily include all contents, operations, or steps, nor must they be executed in the order described. For example, some operations or steps may be decomposed, while others may be combined or partially combined. Therefore, the actual execution order may vary depending on the actual situation.

[0043] The terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish between different objects, not to describe a particular order. Furthermore, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0044] Those skilled in the art will understand that the drawings are merely schematic diagrams of example embodiments, and the modules or processes in the drawings are not necessarily necessary for implementing the present application, and therefore cannot be used to limit the scope of protection of the present application.

[0045] Figure 1 FIG1 shows a first embodiment of a circuit structure diagram of an exemplary current interruption device.

[0046] like Figure 1 As shown, the current shutoff device includes a first flow branch (A), a second flow branch (B), a first transfer branch (C), a second transfer branch (D) and an energy consumption branch (E).

[0047] The first flow branch (A) and the first transfer branch (C) are connected in series to form the first bridge arm. The midpoint of the series connection between the first flow branch (A) and the first transfer branch (C) serves as the first port of the current interruption device. The second flow branch (B) and the energy consumption branch (E) are connected in series to form the second bridge arm. The midpoint of the series connection between the second flow branch (B) and the energy consumption branch (E) serves as the second port of the current interruption device. The first bridge arm, the second bridge arm, and the second transfer branch (D) are connected in parallel.

[0048] The first current-passing branch (A) includes at least two sets of mechanical switches and nonlinear resistors connected in parallel and connected in series. The second current-passing branch (B) includes a mechanical switch or at least two mechanical switches connected in series. The second transfer branch (D) includes a capacitor or at least two capacitors connected in series. The energy-dissipating branch (E) includes a nonlinear resistor or at least two nonlinear resistors connected in series.

[0049] The nonlinear resistor includes at least one arrester or nonlinear resistor. The capacitor is usually several uf or more than ten uf, with high voltage resistance and small size.

[0050] The current shutoff device also includes a reactor unit and a self-excitation module unit. The reactor unit and the self-excitation module unit are connected in series within the parallel loop of the first bridge arm and the second transfer branch (D). The reactor unit is connected in series within the first flow branch (A), the first transfer branch (C), or the second transfer branch (D), and the self-excitation module unit is connected in series within the first flow branch (A), the first transfer branch (C), or the second transfer branch (D).

[0051] The reactor unit includes a reactor, or at least two reactors connected in series or in parallel. The self-excitation module unit includes a self-excitation module, or at least two self-excitation modules connected in series or in parallel.

[0052] Figure 1 This is an embodiment in which the reactor unit is arranged inside the first transfer branch (C), and the self-excitation module unit is arranged inside the second transfer branch (D).

[0053] Figure 2 A second embodiment of a circuit structure diagram of an exemplary current interruption device is shown.

[0054] Figure 2 The circuit structure shown is Figure 1 The circuit structures shown are basically similar, the only difference is: Figure 2 This is an embodiment in which the reactor unit is arranged inside the second transfer branch (D), and the self-excitation module unit is arranged inside the first transfer branch (C).

[0055] Figure 3 A third embodiment of a circuit structure diagram of an exemplary current interruption device is shown.

[0056] Figure 3 The circuit structure shown is Figure 1 The circuit structures shown are basically similar, the only difference is: Figure 3 This is an embodiment in which the reactor unit is arranged inside the first flow branch (A), and the self-excitation module unit is arranged inside the second transfer branch (D).

[0057] Figure 4 A fourth embodiment of a circuit structure diagram of an exemplary current interruption device is shown.

[0058] Figure 4 The circuit structure shown is Figure 1 The circuit structures shown are basically similar, the only difference is: Figure 4 This is an embodiment in which the reactor unit is arranged inside the second transfer branch (D), and the self-excitation module unit is arranged inside the first flow branch (A).

[0059] Figure 5 A fifth embodiment of a circuit structure diagram of an exemplary current interruption device is shown.

[0060] Figure 5 The circuit structure shown is Figure 1 The circuit structures shown are basically similar, the only difference is: Figure 5 This is an embodiment in which the reactor unit is arranged inside the first flow branch (A), and the self-excitation module unit is arranged inside the first transfer branch (C).

[0061] Figure 6 A sixth embodiment of a circuit structure diagram of an exemplary current interruption device is shown.

[0062] Figure 6 The circuit structure shown is Figure 1 The circuit structures shown are basically similar, the only difference is: Figure 6 This is an embodiment in which the reactor unit is arranged inside the first transfer branch (C), and the self-excitation module unit is arranged inside the first flow branch (A).

[0063] Figure 7 A seventh embodiment of a circuit structure diagram of an exemplary current interruption device is shown.

[0064] Figure 7 The circuit structure shown is Figure 1 The circuit structures shown are basically similar, the only difference is: Figure 7 This is an embodiment in which the reactor unit and the self-excitation module unit are arranged inside the second transfer branch (D).

[0065] Figure 8 An eighth embodiment of a circuit structure diagram of an exemplary current interruption device is shown.

[0066] Figure 8 The circuit structure shown is Figure 1 The circuit structures shown are basically similar, the only difference is: Figure 8 This is an embodiment in which the reactor unit and the self-excitation module unit are arranged inside the first transfer branch (C).

[0067] Figure 9 A ninth embodiment of a circuit structure diagram of an exemplary current interruption device is shown.

[0068] Figure 9 The circuit structure shown is Figure 1 The circuit structures shown are basically similar, the only difference is: Figure 9 This is an embodiment in which the reactor unit and the self-excitation module unit are arranged inside the first flow branch (A).

[0069] exist Figures 1-9 In the illustrated embodiment, when the reactor unit is connected in series inside the first current branch (A), the reactor unit includes a saturable reactor for limiting the current change rate of the mechanical switch current in the first current branch at the zero-crossing moment.

[0070] According to some embodiments, the first pass-through branch (A) may further include a saturable reactor connected in series with the mechanical switch in the first pass-through branch to limit the rate of change of the mechanical switch current in the first pass-through branch at the moment the current passes through zero. The second pass-through branch (B) may further include a saturable reactor connected in series with the mechanical switch in the second pass-through branch to limit the rate of change of the mechanical switch current in the second pass-through branch at the moment the current passes through zero.

[0071] A saturable reactor consists of a single saturated reactor or at least two saturated reactors connected in series or parallel. The saturated reactor has a capacitance of several to tens of uH in its saturated state and typically over a hundred uH in its unsaturated state. When shutting off a fault current, the saturated reactor limits the di / dt before the zero crossing, thereby increasing the reliability of the mechanical switch's arc-extinguishing shutdown.

[0072] Figure 10A The first embodiment shows a circuit structure diagram of an exemplary self-excitation module.

[0073] like Figure 10A As shown, the self-oscillating module has a half-bridge structure. It includes a first power electronic switch 1a, a second power electronic switch 2a, and a first voltage source 1b. The positive electrode of the first power electronic switch 1a is connected to the positive electrode of the first voltage source 1b, the negative electrode of the first power electronic switch 1a is connected to the positive electrode of the second power electronic switch 2a, and then leads to an external connection. The negative electrode of the second power electronic switch 2a is connected to the negative electrode of the first voltage source 1b, and then leads to an external connection.

[0074] Figure 10B A second embodiment of a circuit structure diagram of an exemplary self-excitation module is shown;

[0075] like Figure 10B As shown, the self-excitation module has a full-bridge structure. The self-excitation module includes a third power electronic switch 3a, a fourth power electronic switch 4a, a fifth power electronic switch 5a, a sixth power electronic switch 6a, and a second voltage source 2b. The positive electrode of the third power electronic switch 3a is connected to the positive electrode of the fifth power electronic switch 5a and the positive electrode of the second voltage source 2b, respectively. The negative electrode of the fourth power electronic switch 4a is connected to the negative electrode of the sixth power electronic switch 6a and the negative electrode of the second voltage source 2b, respectively. The negative electrode of the third power electronic switch 3a is connected to the positive electrode of the fourth power electronic switch 4a and then leads to an external wire. The negative electrode of the fifth power electronic switch 5a is connected to the positive electrode of the sixth power electronic switch 6a and then leads to an external wire.

[0076] Figure 10C A third embodiment of a circuit structure diagram of an exemplary self-excitation module is shown;

[0077] like Figure 10CAs shown, the self-excitation module has a half-bridge structure. The self-excitation module includes a seventh power electronic switch 7a, an eighth power electronic switch 8a, a third voltage source 3b, and a fourth voltage source 4b. The positive electrode of the seventh power electronic switch 7a is connected to the positive electrode of the third voltage source 3b, the negative electrode of the eighth power electronic switch 8a is connected to the negative electrode of the fourth voltage source 4b, the negative electrode of the seventh power electronic switch 7a is connected to the positive electrode of the eighth power electronic switch 8a, and then leads to an external connection. The negative electrode of the third voltage source 3b is connected to the positive electrode of the fourth voltage source 4b, and then leads to an external connection.

[0078] According to some embodiments, the first power electronic switch 1a, the second power electronic switch 2a, the third power electronic switch 3a, the fourth power electronic switch 4a, the fifth power electronic switch 5a, the sixth power electronic switch 6a, the seventh power electronic switch 7a and the eighth power electronic switch 8a include a one-stage power semiconductor device, or at least two stages of power semiconductor devices connected in series or in parallel.

[0079] Among them, the power semiconductor device includes a fully controlled power semiconductor device or a half-controlled power semiconductor device.

[0080] The fully controlled power semiconductor device includes at least one of IGBT, IEGT, IGCT, MOSFET and GTO. The half controlled power semiconductor device includes thyristor.

[0081] The first voltage source 1b, the second voltage source 2b, the third voltage source 3b, and the fourth voltage source 4b include at least one of a pre-charged capacitor, an energy storage battery, and an AC rectifier power supply. To protect the voltage source from overvoltage damage during current shutdown, overvoltage protection measures, such as lightning arresters or chopper circuits, may be connected in parallel across the voltage source.

[0082] Figure 11 A flow chart of an exemplary control method of a current interruption device is shown.

[0083] When the power system is fault-free, the current-shutoff device operates in the closed position. The mechanical switch of the first current-passing branch (A) is closed, and the mechanical switch of the second current-passing branch (B) is closed, allowing current to flow through the first current-passing branch (A) and the second current-passing branch (B). When a power system fault occurs, the following opening and reclosing operations are performed.

[0084] In step S701, a tripping instruction is output to disconnect the mechanical switches of the first flow branch and the second flow branch.

[0085] The current shut-off device receives the tripping instruction, turns on the output tripping instruction, and disconnects the mechanical switches of the first current branch and the second current branch.

[0086] In step S702, when the mechanical switches of the first flow branch and the second flow branch are separated to the insulation position, the self-excitation module unit is triggered to output a single-pulse or multi-pulse square wave voltage to stimulate the oscillation of the capacitor and the reactor unit of the second transfer branch, thereby generating an oscillating current with an amplitude equal to and opposite to the fault current. The oscillating current causes the mechanical switch of the first flow branch to turn off through zero.

[0087] According to some embodiments, when the current shut-off device is used for a load switch, the load current that is usually shut off is relatively small, and the self-excitation module unit can be designed to have a single-pulse output, with a pulse frequency close to the resonant frequency of the capacitor and the reactor, and the generated single-pulse current peak value is greater than the load current amplitude; when the current shut-off device is used for a circuit breaker, the fault current that is usually shut off is relatively large, and the self-excitation module unit can be designed to have a multi-pulse output, with a pulse frequency close to the resonant frequency of the capacitor and the reactor, and the continuously increasing current peak value generated by multiple oscillations is greater than the fault current amplitude.

[0088] In step S703, corresponding to the case where the mechanical switch of the first flow-through branch is turned off at zero crossing, the fault current charges the capacitor of the second transfer branch. When the voltage across the capacitor is greater than the operating voltage of the nonlinear resistor of the energy-consuming branch, the fault current is transferred to the energy-consuming branch, so that the mechanical switch of the second flow-through branch is turned off at zero crossing, and the fault current is dissipated to zero through the energy-consuming branch.

[0089] In step S704 , when the fault current dissipates to zero, the mechanical switches of the first flow-through branches are closed group by group, so that the capacitor of the second transfer branch is discharged through the nonlinear resistor of the first flow-through branch.

[0090] In step S705, a reclosing command is output to close the mechanical switch of the second flow branch.

[0091] In step S706 , when the current interrupting device is reclosed to the faulty power system, the opening operation is performed again and step S701 is re-executed; if the current interrupting device is reclosed to the normal power system, the reclosing is successful.

[0092] The current shut-off device and control method provided in the present application, when the current shut-off device is tripped, by controlling the operating states of the internal components of the flow branch and the transfer branch, the transfer branch generates an oscillating current with an amplitude equal to and a direction opposite to the fault current, thereby reliably shutting off the flow branch, overcoming the problems of high risk of reignition of mechanical switches, long shutdown time for small currents, significant oscillation with the power system, and high equipment cost, and being conducive to large-scale promotion and application in AC and DC power transmission and distribution systems; by closing multiple groups of mechanical switches in the flow branch one by one, the energy release of the capacitor during the last tripping operation is realized, effectively reducing the size of the closing / reclosing inrush current and improving the life of the mechanical switch.

[0093] The present application can connect multiple current interruption devices in series, that is, adopt a modular series connection method to achieve flexible expansion, such as Figure 12 As shown, it can meet the application requirements of high-voltage systems or the requirements of compact engineering structure design.

[0094] It should be clearly understood that this application describes how to form and use specific examples, but this application is not limited to any details of these examples. On the contrary, based on the teaching of the content disclosed in this application, these principles can be applied to many other embodiments.

[0095] Furthermore, it should be noted that the aforementioned figures are merely illustrative of the processes included in the methods according to exemplary embodiments of the present application and are not intended to be limiting. It is readily understood that the processes illustrated in the aforementioned figures do not indicate or limit the temporal order of these processes. Furthermore, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0096] While the exemplary embodiments of the present application have been specifically illustrated and described above, it should be understood that the present application is not limited to the detailed structures, configurations, or implementations described herein; rather, the present application is intended to encompass various modifications and equivalent configurations within the spirit and scope of the appended claims.

Claims

1. A current shutoff device, characterized in that: include: a first flow branch comprising at least two sets of mechanical switches and nonlinear resistors connected in parallel and connected in series; a second flow branch, the second flow branch comprising a mechanical switch or at least two mechanical switches connected in series; First transfer branch; a second transfer branch, the second transfer branch comprising a capacitor, or at least two capacitors connected in series, wherein the first pass-through branch is configured to discharge the capacitors of the second transfer branch through the nonlinear resistors of the first pass-through branch by closing the mechanical switches of the first pass-through branch group by group when a fault occurs in the power system and the fault current dissipates to zero; an energy dissipation branch, the energy dissipation branch comprising a nonlinear resistor, or at least two nonlinear resistors connected in series, wherein the first flow branch and the first transfer branch are connected in series to form a first bridge arm, the midpoint of the series connection between the first flow branch and the first transfer branch being the first port of the current shutoff device, the second flow branch and the energy dissipation branch are connected in series to form a second bridge arm, the midpoint of the series connection between the second flow branch and the energy dissipation branch being the second port of the current shutoff device, and the first bridge arm, the second bridge arm, and the second transfer branch are connected in parallel; The reactor unit and the self-excitation module unit are connected in series in the parallel loop of the first bridge arm and the second transfer branch. The reactor unit is connected in series inside the first flow branch, the first transfer branch or the second transfer branch. The self-excitation module unit is connected in series inside the first flow branch, the first transfer branch or the second transfer branch.

2. The current interruption device according to claim 1, wherein: In the case where the reactor unit is connected in series inside the first current-passing branch, the reactor unit includes a saturable reactor, which is used to limit the current change rate of the mechanical switch current in the first current-passing branch at the zero-crossing moment.

3. The current interruption device according to claim 1, wherein: The first flow branch further includes a saturable reactor connected in series with the mechanical switch in the first flow branch, and is used to limit the current change rate of the mechanical switch in the first flow branch at the moment when the current passes through zero.

4. The current interruption device according to claim 1, wherein: The second flow branch further includes a saturable reactor connected in series with the mechanical switch in the second flow branch, and is used to limit the current change rate of the mechanical switch in the second flow branch at the moment when the current passes through zero.

5. The current interruption device according to claim 1, wherein: The self-excitation module has a half-bridge structure and includes a first power electronic switch, a second power electronic switch, and a first voltage source. The positive electrode of the first power electronic switch is connected to the positive electrode of the first voltage source, the negative electrode of the first power electronic switch is connected to the positive electrode of the second power electronic switch and then leads to an external wire, and the negative electrode of the second power electronic switch is connected to the negative electrode of the first voltage source and then leads to an external wire. or The self-excitation module has a full-bridge structure and includes a third power electronic switch, a fourth power electronic switch, a fifth power electronic switch, a sixth power electronic switch, and a second voltage source. The positive electrode of the third power electronic switch is connected to the positive electrode of the fifth power electronic switch and the positive electrode of the second voltage source, respectively. The negative electrode of the fourth power electronic switch is connected to the negative electrode of the sixth power electronic switch and the negative electrode of the second voltage source, respectively. The negative electrode of the third power electronic switch is connected to the positive electrode of the fourth power electronic switch and then leads to an external wire. The negative electrode of the fifth power electronic switch is connected to the positive electrode of the sixth power electronic switch and then leads to an external wire. Or The self-excitation module has a half-bridge structure and includes a seventh power electronic switch, an eighth power electronic switch, a third voltage source, and a fourth voltage source. The positive electrode of the seventh power electronic switch is connected to the positive electrode of the third voltage source, the negative electrode of the eighth power electronic switch is connected to the negative electrode of the fourth voltage source, the negative electrode of the seventh power electronic switch is connected to the positive electrode of the eighth power electronic switch and then leads to an external wire, and the negative electrode of the third voltage source is connected to the positive electrode of the fourth voltage source and then leads to an external wire.

6. The current interruption device according to claim 5, wherein: The first power electronic switch, the second power electronic switch, the third power electronic switch, the fourth power electronic switch, the fifth power electronic switch, the sixth power electronic switch, the seventh power electronic switch, and the eighth power electronic switch include a single-stage power semiconductor device, or at least two stages of power semiconductor devices connected in series or in parallel, wherein: The power semiconductor device includes a fully controlled power semiconductor device or a half-controlled power semiconductor device.

7. The current interruption device according to claim 6, wherein: The fully controlled power semiconductor device includes at least one of IGBT, IEGT, IGCT, MOSFET and GTO; The half-controlled power semiconductor device includes a thyristor.

8. The current interruption device according to claim 5, wherein: The first voltage source, the second voltage source, the third voltage source and the fourth voltage source include at least one of a pre-charge capacitor, an energy storage battery and an AC rectifier power supply.

9. A method for controlling a current interruption device according to any one of claims 1 to 8, characterized in that: include: a. In the event of a power system failure, outputting a tripping command to disconnect the mechanical switches of the first flow branch and the second flow branch; b. When the mechanical switches of the first and second current-passing branches are separated to the insulation-open position, triggering the self-excitation module unit to output a single-pulse or multi-pulse square wave voltage to excite the capacitor of the second transfer branch and the reactor of the reactor unit to oscillate, generating an oscillating current with an amplitude equal to and a direction opposite to the fault current, wherein the oscillating current causes the mechanical switch of the first current-passing branch to turn off through zero crossing; c. In response to the mechanical switch of the first current-carrying branch being turned off at zero crossing, the fault current charges the capacitor of the second transfer branch. When the voltage across the capacitor is greater than the operating voltage of the nonlinear resistor of the energy-consuming branch, the fault current is transferred to the energy-consuming branch, causing the mechanical switch of the second current-carrying branch to be turned off at zero crossing, and the fault current is dissipated to zero through the energy-consuming branch. d. When the fault current dissipates to zero, closing the mechanical switches of the first flow-through branches in groups one by one, so that the capacitor of the second transfer branch discharges through the nonlinear resistor of the first flow-through branch; e. Outputting a reclosing command to close the mechanical switch of the second flow branch; f. When the current interruption device is reclosed to the faulty power system, re-execute step a.

10. The control method according to claim 9, wherein: Also includes: When no fault occurs in the power system, the mechanical switches of the first flow branch and the second flow branch are in a closed state.

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