Current breaking device and control method thereof

Abstract

The invention provides a current breaking device and a control method thereof. The current breaking device comprises a main branch circuit, the main branch circuit comprises at least two groups of through-flow units which are connected in series, and each through-flow unit comprises a first mechanical switch and a first non-linear resistor which are connected in parallel; the transfer branch circuit is connected with the main branch circuit in parallel, and the transfer branch circuit comprises an oscillation capacitor; the isolation branch circuit is connected with the main branch circuit in series, and the isolation branch circuit comprises a second mechanical switch; the oscillation inductor and the power electronic unit are connected in series in a parallel loop of the main branch and the transfer branch, the oscillation inductor is connected in series in the main branch or the transfer branch, and the power electronic unit is connected in series in the main branch or the transfer branch.

Description

Technical Field

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

[0002] In DC applications, due to the rapid growth of fault current in DC transmission and distribution systems, reliable fault rapid isolation and recovery are the key to ensuring safe and stable operation. Existing DC circuit breakers include mechanical DC circuit breakers, hybrid DC circuit breakers, and all-solid-state DC circuit breakers.

[0003] Among them, mechanical DC circuit breakers can be divided into passive oscillation technology and active oscillation technology. Since mechanical DC circuit breakers use large-capacity capacitors, they have the disadvantages of being large in size, taking a long time to break small currents, having a high risk of restrike when the mechanical switch crosses zero, and the shutdown process is prone to oscillation with the DC system, posing a hidden danger to the normal and safe operation of the system and other equipment.

[0004] The hybrid DC circuit breaker combines mechanical switches and power electronics technology to achieve controlled current shutdown through power electronic devices. It has the characteristics of arc-free and fast reclosing, and has good system applicability. However, the technical performance of the shutdown current and the economic performance of the equipment are limited by fully controlled power electronic devices, which is not conducive to its large-scale promotion and application in high-voltage DC transmission systems.

[0005] The existing patent CN108475595A proposes a DC circuit breaker based on the LC active resonance principle, which can solve the problems of DC circuit breakers in the prior art, such as high risk of mechanical switch reignition, long small current shutdown time, significant system oscillation and high equipment cost. However, it has defects in closing / reclosing operations, and requires the addition of additional discharge circuits or the mechanical switch to withstand a large closing inrush current.

[0006] The above information disclosed in the Background section is only for enhancement of understanding of the background of the present application and therefore it may contain information that does not constitute the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0007] In order to solve at least one of the above problems, the present application proposes a current interrupting device and a control method thereof.

[0008] According to the first aspect of the present application, at least one embodiment of the present application provides a current interrupting device, comprising: a main branch, the main branch comprising at least two groups of current-passing units connected in series, wherein the current-passing unit comprises a first mechanical switch and a first nonlinear resistor connected in parallel; a transfer branch, the transfer branch is connected in parallel with the main branch, and the transfer branch comprises an oscillation capacitor; an isolation branch, the isolation branch is connected in series with the main branch, and the isolation branch comprises a second mechanical switch; and an oscillating inductor and a power electronic unit, which are connected in series in a parallel loop of the main branch and the transfer branch, the oscillating inductor is connected in series inside the main branch or inside the transfer branch, and the power electronic unit is connected in series inside the main branch or inside the transfer branch.

[0009] For example, in some embodiments of the present application, it also includes: a second nonlinear resistor, which is connected in parallel with the oscillation capacitor, or in parallel with the series branch of the oscillation capacitor and the oscillation inductor, or in parallel with the series branch of the oscillation capacitor and the power electronic unit, or in parallel with the transfer branch.

[0010] For example, in some embodiments of the present application, the power electronic unit includes one power electronic module or at least two power electronic modules connected in series.

[0011] For example, in some embodiments of the present application, the power electronic module 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 wiring, 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 wiring; or 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 respectively connected to the positive electrode of the fifth power electronic switch and the positive electrode of the second voltage source, and the negative electrode of the fourth power electronic switch is respectively connected to the positive electrode of the fifth power electronic switch and the positive electrode of the second voltage source. The negative electrode of the sixth power electronic switch is connected to 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 an external wire is led out, and the negative electrode of the fifth power electronic switch is connected to the positive electrode of the sixth power electronic switch and then an external wire is led out; or the seventh power electronic switch, the eighth power electronic switch, the third voltage source and the 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 an external wire is led out, and the negative electrode of the third voltage source is connected to the positive electrode of the fourth voltage source and then an external wire is led out.

[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 primary power semiconductor device, or at least two stages of power semiconductor devices are 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; 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.

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

[0014] For example, in some embodiments of the present application, the first mechanical switch or the second mechanical switch includes a mechanical switch, or at least two mechanical switches connected in series or in parallel; the oscillation capacitor includes a capacitor, or at least two capacitors connected in series or in parallel; the oscillation inductor includes an inductor, or at least two inductors connected in series or in parallel; the first nonlinear resistor includes a nonlinear resistor, or at least two nonlinear resistors connected in series or in parallel.

[0015] According to the second aspect of the present application, at least one embodiment of the present application provides a control method for a current breaking device as described in any one of the first aspects, comprising: a. in the event of a system fault, outputting a trip command to disconnect the first mechanical switch of the main branch; b. when the first mechanical switch is separated to the insulation position, triggering the power electronic unit to output a single-pulse or multi-pulse square wave voltage to excite the oscillation capacitor and the oscillation inductor to oscillate, so that the transfer branch generates an oscillating current with an amplitude equal to that of the fault current and in an opposite direction, and the oscillating current causes the first mechanical switch to cross zero and shut down; c. corresponding to the situation where the first mechanical switch is turned off at zero, the fault current is given The oscillation capacitor of the transfer branch is charged. When the voltage across the oscillation capacitor is greater than the operating voltage of the first nonlinear resistor or the second nonlinear resistor, the fault current is transferred to the first nonlinear resistor or the second nonlinear resistor, and the fault current dissipates to zero; d. Open the second mechanical switch of the isolation branch; e. Close the first mechanical switches of the main branch one by one to discharge the oscillation capacitor of the transfer branch through the first nonlinear resistor of the main branch; f. Output a reclosing command to close the second mechanical switch of the isolation branch; g. When the current breaking device recloses on the fault system, re-execute step a.

[0016] For example, in some embodiments of the present application, it also includes: when there is no fault in the system, the first mechanical switch of the main branch is in a closed state, the second mechanical switch of the isolation branch is in a closed state, and the power electronic module of the transfer branch is in a locked state or a cut-off state.

[0017] For example, in some embodiments of the present application, the step of opening the second mechanical switch of the isolation branch includes: executing step d during the execution of step a, step b or step c.

[0018] The present application provides a current breaking device and a control method thereof. When the current breaking device is opened, by controlling the operating states of the internal components of the main branch and the transfer branch, the transfer branch generates an oscillating current with an amplitude equal to and opposite to the fault current, thereby reliably shutting down the main branch, overcoming the problems of high risk of reignition of mechanical switches, long shutdown time for small currents, significant system oscillations, and high equipment costs, 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 main branch one by one, the energy release of the oscillation capacitor during the last opening operation is realized, effectively reducing the size of the closing / reclosing surge current and increasing the life of the mechanical switch.

[0019] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] 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 accompanying drawings described below are only some embodiments of the present application, and are not intended to limit the present application.

[0021] Figure 1 A first embodiment of an exemplary current interrupting device is shown;

[0022] Figure 2 A second embodiment of an exemplary current interrupting device is shown;

[0023] Figure 3 A third embodiment of an exemplary current interrupting device is shown;

[0024] Figure 4 A fourth embodiment of an exemplary current interrupting device is shown;

[0025] Figure 5 A fifth embodiment of an exemplary current interrupting device is shown;

[0026] Fig. 6A A first embodiment of an exemplary power electronic module is shown;

[0027] Figure 6B A second embodiment of an exemplary power electronic module is shown;

[0028] Figure 6C A third embodiment of an exemplary power electronic module is shown;

[0029] Figure 7 A flow chart showing an exemplary control method of a current interrupting device;

[0030] Fig. 8A A circuit structure diagram of an exemplary passive power electronic module is shown in Embodiment 1;

[0031] Figure 8B A circuit structure diagram of an exemplary passive power electronic module is shown in Embodiment 2;

[0032] Figure 8C A circuit structure diagram of an exemplary passive power electronic module is shown in Embodiment 3;

[0033] Fig.8D A fourth embodiment of a circuit structure diagram showing an exemplary passive power electronic module;

[0034] Fig. 9A Embodiment 1 showing an extended connection schematic diagram of an exemplary current interrupting device;

[0035] Fig. 9BA second embodiment showing an extended connection diagram of an exemplary current interrupting device;

[0036] Fig. 9C A third embodiment of an extended connection diagram of an exemplary current interrupting device is shown. DETAILED DESCRIPTION

[0037] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this application will be comprehensive and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted.

[0038] The described features, structures or characteristics may be combined in one or more embodiments in any suitable manner. 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 modes, components, materials, devices, etc. may be adopted. In these cases, known structures, methods, devices, implementations, materials or operations will not be shown or described in detail.

[0039] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations or steps, nor do they have to be executed in the order described. For example, some operations or steps can be decomposed, and some operations or steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0040] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0041] Those skilled in the art will appreciate 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.

[0042] The present application proposes a current interrupting device. The current interrupting device includes a main branch, a transfer branch, and an isolation branch. Among them, the main branch is connected in parallel with the transfer branch, and the isolation branch is connected in series with the main branch. The main branch includes at least two groups of flow units connected in series. The flow unit includes a first mechanical switch and a first nonlinear resistor connected in parallel. The transfer branch includes an oscillation capacitor. The isolation branch includes a second mechanical switch. An oscillating inductor and a power electronic unit are connected in series in a parallel loop of the main branch and the transfer branch, the oscillating inductor is connected in series inside the main branch or inside the transfer branch, and the power electronic unit is connected in series inside the main branch or inside the transfer branch.

[0043] Figure 1 A first embodiment of an exemplary current interrupting device is shown.

[0044] like Figure 1 As shown, the current interrupting device comprises a main branch (1), a transfer branch (2), and an isolation branch (3). The main branch (1) is connected in parallel with the transfer branch (2), and the isolation branch (3) is connected in series with the main branch (1). The main branch (1) comprises at least two groups of flow units connected in series. The flow unit comprises a first mechanical switch and a first nonlinear resistor connected in parallel. The transfer branch (2) comprises an oscillation capacitor, an oscillation inductor, and a power electronic unit connected in series. The isolation branch (3) comprises at least one second mechanical switch.

[0045] Figure 2 A second embodiment of an exemplary current interrupting device is shown.

[0046] like Figure 2 As shown, the current interrupting device comprises a main branch (1), a transfer branch (2), an isolation branch (3) and a second nonlinear resistor (4). The main branch (1) is connected in parallel with the transfer branch (2), and the isolation branch (3) is connected in series with the main branch (1). The main branch (1) comprises at least two groups of flow units connected in series. The flow unit comprises a first mechanical switch and a first nonlinear resistor connected in parallel. The transfer branch (2) comprises an oscillation capacitor, an oscillation inductor and a power electronic unit connected in series. The isolation branch (3) comprises at least one second mechanical switch. The second nonlinear resistor (4) is connected in parallel with the oscillation capacitor.

[0047] Figure 3 A third exemplary embodiment of a current interrupting device is shown.

[0048] like Figure 3As shown, the current interrupting device comprises a main branch (1), a transfer branch (2), an isolation branch (3) and a second nonlinear resistor (4). The main branch (1) is connected in parallel with the transfer branch (2), and the isolation branch (3) is connected in series with the main branch (1). The main branch (1) comprises at least two groups of flow units connected in series. The flow units comprise a first mechanical switch and a first nonlinear resistor connected in parallel. The transfer branch (2) comprises an oscillation capacitor, an oscillation inductor and a power electronic unit connected in series. The isolation branch (3) comprises at least one second mechanical switch. The second nonlinear resistor (4) is connected in parallel with the series branch of the oscillation capacitor and the oscillation inductor.

[0049] Figure 4 A fourth embodiment of an exemplary current interrupting device is shown.

[0050] like Figure 4 As shown, the current interrupting device comprises a main branch (1), a transfer branch (2), an isolation branch (3) and a second nonlinear resistor (4). The main branch (1) is connected in parallel with the transfer branch (2), and the isolation branch (3) is connected in series with the main branch (1). The main branch (1) comprises at least two groups of flow units connected in series. The flow unit comprises a first mechanical switch and a first nonlinear resistor connected in parallel. The transfer branch (2) comprises an oscillation capacitor, an oscillation inductor and a power electronic unit connected in series. The isolation branch (3) comprises at least one second mechanical switch. The second nonlinear resistor (4) is connected in parallel with the series branch of the oscillation capacitor and the power electronic unit.

[0051] Figure 5 A fifth embodiment of an exemplary current interrupting device is shown.

[0052] like Figure 5 As shown, the current interrupting device comprises a main branch (1), a transfer branch (2), an isolation branch (3) and a second nonlinear resistor (4). The main branch (1) is connected in parallel with the transfer branch (2), and the isolation branch (3) is connected in series with the main branch (1). The main branch (1) comprises at least two groups of flow units connected in series. The flow units comprise a first mechanical switch and a first nonlinear resistor connected in parallel. The transfer branch (2) comprises an oscillation capacitor, an oscillation inductor and a power electronic unit connected in series. The isolation branch (3) comprises at least one second mechanical switch. The second nonlinear resistor (4) is connected in parallel with the transfer branch (2).

[0053] According to some embodiments, the power electronic unit comprises one power electronic module or at least two power electronic modules connected in series.

[0054] Fig. 6A A first embodiment of an exemplary power electronic module is shown.

[0055] like Fig. 6AAs shown, the power electronic module 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 wire, and 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 wire.

[0056] Figure 6B A second embodiment of an exemplary power electronic module is shown.

[0057] like Figure 6B As shown, the power electronic 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 respectively connected to the positive electrode of the fifth power electronic switch 5a and the positive electrode of the second voltage source 2b, the negative electrode of the fourth power electronic switch 4a is respectively connected to the negative electrode of the sixth power electronic switch 6a and the negative electrode of the second voltage source 2b, 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, and 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.

[0058] Figure 6C A third embodiment of an exemplary power electronic module is shown.

[0059] like Figure 6C As shown, the power electronic 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 pole of the seventh power electronic switch 7a is connected to the positive pole of the third voltage source 3b, the negative pole of the eighth power electronic switch 8a is connected to the negative pole of the fourth voltage source 4b, the negative pole of the seventh power electronic switch 7a is connected to the positive pole of the eighth power electronic switch 8a and then an external wiring is led out, and the negative pole of the third voltage source 3b is connected to the positive pole of the fourth voltage source 4b and then an external wiring is led out.

[0060] 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 primary power semiconductor device, or at least two power semiconductor devices are connected in series or in parallel. The power semiconductor device includes a fully controlled power semiconductor device or a half-controlled power semiconductor device. 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.

[0061] 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. In order to protect the voltage source and prevent overvoltage damage during the current shutdown process, overvoltage measures such as lightning arresters or chopper circuits can be connected in parallel at both ends.

[0062] The first mechanical switch or the second mechanical switch includes a mechanical switch, or at least two mechanical switches connected in series or in parallel. Usually, it is a fast type fast switch, and can adopt a mechanical switch based on electromagnetic repulsion, permanent magnetism, or explosion. When multiple fast switches are connected in series, an RC circuit is usually connected in parallel next to each fast switch to improve the voltage balancing performance.

[0063] The oscillation capacitor includes one capacitor, or at least two capacitors connected in series or in parallel.

[0064] The oscillating inductor includes one inductor, or at least two inductors connected in series or in parallel.

[0065] The first nonlinear resistor includes one nonlinear resistor, or at least two nonlinear resistors connected in series or in parallel. The nonlinear resistor is usually a zinc oxide arrester.

[0066] Figure 7 A flow chart of an exemplary control method of a current interrupting device is shown.

[0067] When the system does not fail, the current breaking device is initially in the closed position, the current flows through the main branch (1) and the isolation branch (3), the first mechanical switch of the main branch (1) is in the closed state, the second mechanical switch of the isolation branch (3) is in the closed state, and the power electronic module of the transfer branch (2) is in the locked state or the cut-off state. When the system fails, the following opening and reclosing operations are performed.

[0068] In step S701, a switch-off instruction is output to disconnect the first mechanical switch of the main branch.

[0069] The current breaking device receives the opening command and opens the first mechanical switch of the main branch.

[0070] In step S702, when the first mechanical switch is separated to the insulation position, the power electronic unit is triggered to output a single-pulse or multi-pulse square wave voltage to excite the oscillation capacitor and the oscillation inductor to oscillate, so that the transfer branch generates an oscillating current with an amplitude equal to and opposite to the fault current, and the oscillating current causes the first mechanical switch to turn off at zero point.

[0071] According to some embodiments, when the current interrupting device is used for a load switch, the load current that is usually shut off is relatively small, and the power electronic unit can be designed to have a single pulse output, with a pulse frequency close to the resonant frequency of the oscillation capacitor and the oscillation inductor, and the generated single pulse current peak value is greater than the load current amplitude; when the current interrupting device is used for a circuit breaker, the fault current that is usually shut off is relatively large, and the power electronic unit can be designed to have a multi-pulse output, with a pulse frequency close to the resonant frequency of the oscillation capacitor and the oscillation inductor, and the continuously increasing current peak value generated by multiple oscillations is greater than the fault current amplitude.

[0072] In step S703, corresponding to the situation where the first mechanical switch is turned off at zero crossing, the fault current charges the oscillation capacitor of the transfer branch. When the voltage across the oscillation capacitor is greater than the operating voltage of the first nonlinear resistor or the second nonlinear resistor, the fault current is transferred to the first nonlinear resistor or the second nonlinear resistor, and the fault current dissipates to zero.

[0073] In step S704, the second mechanical switch of the isolation branch is opened.

[0074] According to some embodiments, the step of opening the second mechanical switch of the isolation branch may be performed when executing steps S701 , S702 , and S703 .

[0075] In step S705, the first mechanical switches of the main branch are closed group by group, so that the oscillation capacitor of the transfer branch is discharged through the first nonlinear resistor of the main branch.

[0076] In step S706, a reclosing instruction is output to close the second mechanical switch of the isolation branch.

[0077] In the case where the current interrupting device overlaps with the faulty system, the opening operation is performed again and step S701 is re-executed; if the current interrupting device overlaps with the normal system, the reclosing is successful.

[0078] The current breaking device and control method provided in the present application, when the current breaking device is opened, by controlling the operating states of the internal components of the main branch and the transfer branch, the transfer branch generates an oscillating current with an amplitude equal to and opposite to the fault current, thereby reliably shutting down the main branch, overcoming the problems of high risk of reignition of mechanical switches, long shutdown time for small currents, significant system oscillations, and high equipment costs, 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 main branch one by one, the energy release of the oscillation capacitor during the last opening operation is realized, effectively reducing the size of the closing / reclosing surge current and increasing the life of the mechanical switch.

[0079] According to some embodiments, the oscillating inductor in the transfer branch of the present application can be arranged in the main branch, an oscillating inductor can be directly connected in series in the main branch, or an oscillating inductor can be connected in series in each current-passing unit. The oscillating inductor arranged in the main branch can be a linear inductor or a saturated inductor.

[0080] According to some embodiments, the power electronic unit in the transfer branch of the present application can also be arranged in the main branch. Multiple power electronic modules can be directly connected in series in the main branch, or multiple power electronic modules can be connected in series in each current-passing unit. In this case, in addition to the active power electronic module topology in FIG6 , the power electronic module can also be Figures 8A-8D The passive power electronic module topology is shown.

[0081] Fig. 8A The circuit structure diagram of an exemplary passive power electronic module in Embodiment 1 is shown, comprising two power electronic switches and a nonlinear resistor connected in parallel, end to end in series.

[0082] Figure 8B The circuit structure diagram of the exemplary passive power electronic module of Embodiment 2 is shown, including two end-to-end parallel power electronic switches and a nonlinear resistor connected in parallel.

[0083] Figure 8C The circuit structure diagram of the exemplary passive power electronic module in Embodiment 3 is shown, including four power electronic switches and a nonlinear resistor. The four power electronic switches form a full-bridge circuit, and the nonlinear resistor is connected in parallel to the DC side of the full-bridge circuit.

[0084] Fig.8D A circuit structure diagram of an exemplary passive power electronic module, Example 4, is shown, including four diodes, a power electronic switch and a nonlinear resistor. The four diodes constitute a diode full-bridge circuit, the power electronic switch is connected in parallel to the DC side of the diode full-bridge circuit, and the nonlinear resistor is connected in parallel to the DC side or AC side of the full-bridge circuit.

[0085] The present application can realize flexible expansion by adopting modular series connection of multiple current interrupting devices, such as Fig. 9A As shown, it can meet the application requirements of high-voltage systems or the requirements of compact engineering structure design.

[0086] The present application can also realize flexible expansion by using modular series connection of the parallel connection of the main branch and the transfer branch, such as Fig. 9B As shown, it can meet the application requirements of high-voltage systems or the requirements of compact engineering structure design.

[0087] The present application can also realize flexible expansion by modularizing the transfer branches in series, such as Fig. 9C As shown, it can meet the application requirements of high-voltage systems or the requirements of compact engineering structure design.

[0088] It should be clearly understood that the present application describes how to form and use specific examples, but the present application is not limited to any details of these examples. On the contrary, based on the teaching of the content disclosed in the present application, these principles can be applied to many other embodiments.

[0089] In addition, it should be noted that the above figures are only schematic illustrations of the processes included in the method according to the exemplary embodiments of the present application, and are not intended to be limiting. It is easy to understand that the processes shown in the above figures do not indicate or limit the time sequence of these processes. In addition, it is also easy to understand that these processes can be performed synchronously or asynchronously, for example, in multiple modules.

[0090] The exemplary embodiments of the present application are specifically shown and described above. It should be understood that the present application is not limited to the detailed structures, configurations or implementations described herein; on the contrary, the present application is intended to cover various modifications and equivalent configurations included in the spirit and scope of the appended claims.

Claims

1. A current interrupting device, characterized in that: include: A main branch, the main branch comprising at least two groups of flow-through units connected in series, wherein the flow-through units comprise a first mechanical switch and a first nonlinear resistor connected in parallel; A transfer branch, the transfer branch is connected in parallel with the main branch, and the transfer branch includes an oscillation capacitor; an isolation branch, the isolation branch being connected in series with the main branch, the isolation branch comprising a second mechanical switch; and An oscillating inductor and a power electronic unit are connected in series in a parallel loop of the main branch and the transfer branch. The oscillating inductor is connected in series inside the main branch or inside the transfer branch, and the power electronic unit is connected in series inside the main branch or inside the transfer branch.

2. The current interrupting device according to claim 1, characterized in that: Also includes: A second nonlinear resistor is connected in parallel with the oscillation capacitor, or in parallel with a series branch of the oscillation capacitor and the oscillation inductor, or in parallel with a series branch of the oscillation capacitor and the power electronic unit, or in parallel with the transfer branch.

3. The current interrupting device according to claim 1, characterized in that: The power electronic unit includes one power electronic module or at least two power electronic modules connected in series.

4. The current interrupting device according to claim 3, characterized in that: The power electronics module comprises: a first power electronic switch, a second power electronic switch and a first voltage source, wherein 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 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, wherein 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, 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 A seventh power electronic switch, an eighth power electronic switch, a third voltage source and a fourth voltage source, wherein 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 an external wiring is led out, and the negative electrode of the third voltage source is connected to the positive electrode of the fourth voltage source and then an external wiring is led out.

5. The current interrupting device according to claim 4, characterized in that: 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-stage power semiconductor device, or at least two-stage power semiconductor devices are connected in series or in parallel, wherein: The power semiconductor device includes a fully controlled power semiconductor device or a semi-controlled power semiconductor device; 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.

6. The current interrupting device according to claim 5, characterized in that: 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.

7. The current interrupting device according to claim 1, characterized in that: The first mechanical switch or the second mechanical switch includes one mechanical switch, or at least two mechanical switches connected in series or in parallel; The oscillation capacitor comprises one capacitor, or at least two capacitors connected in series or in parallel; The oscillating inductor comprises an inductor, or at least two inductors connected in series or in parallel; The first non-linear resistor includes one non-linear resistor, or at least two non-linear resistors connected in series or in parallel.

8. A method for controlling a current interrupting device according to any one of claims 1 to 7, characterized in that: include: a. In the event of a system failure, output a trip command to disconnect the first mechanical switch of the main branch; b. When the first mechanical switch is separated to the insulation position, the power electronic unit is triggered to output a single pulse or a multi-pulse square wave voltage to excite the oscillation capacitor and the oscillation inductor to oscillate, so that the transfer branch generates an oscillating current with an amplitude equal to that of the fault current and in an opposite direction, and the oscillating current causes the first mechanical switch to turn off through zero; c. In response to the first mechanical switch being turned off at zero crossing, the fault current charges the oscillation capacitor of the transfer branch. When the voltage across the oscillation capacitor is greater than the operating voltage of the first nonlinear resistor or the second nonlinear resistor, the fault current is transferred to the first nonlinear resistor or the second nonlinear resistor, and the fault current dissipates to zero. d. Opening the second mechanical switch of the isolation branch; e. Closing the first mechanical switches of the main branch in groups one by one, so that the oscillation capacitor of the transfer branch discharges through the first nonlinear resistor of the main branch; f. outputting a reclosing command to close the second mechanical switch of the isolation branch; g. When the current interrupting device overlaps with the faulty system, re-execute step a.

9. The control method according to claim 8, characterized in that: Also includes: When no fault occurs in the system, the first mechanical switch of the main branch is in a closed state, the second mechanical switch of the isolation branch is in a closed state, and the power electronic module of the transfer branch is in a locked state or a cut-off state.

10. The control method according to claim 8, characterized in that: The second mechanical switch for opening the isolation branch comprises: During the execution of step a, step b or step c, execute step d.

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