Current interruption device and its control method

Abstract

The present application provides a current breaking device and a control method therefor. The current breaking device includes: a main branch, the main branch including n groups of current-carrying units connected in series; a transfer branch, the transfer branch being connected in parallel with the main branch, the transfer branch including n groups of oscillating capacitor units connected in series; an isolation branch, the isolation branch being connected in series with the main branch; a discharge branch, the discharge branch including n - 1 groups of discharge units; a power consumption branch, the power consumption branch being connected in parallel with the main branch, or the power consumption branch including n groups of power consumption units connected in series, the i-th group of power consumption units being connected in parallel with the i-th group of current-carrying units, or the i-th group of power consumption units being connected in parallel with the i-th group of oscillating capacitor units or internal components of the oscillating capacitor units; an oscillating inductor unit and a power electronic unit, being connected in series within a parallel loop of the main branch and the transfer branch, the oscillating inductor unit being connected in series within the main branch or the transfer branch, and the power electronic unit being connected in series within the main branch or the transfer branch.

Description

Technical Field

[0001] This application relates to the field of power electronics technology. Specifically, it relates to a current breaking device and its control method. Background Art

[0002] In the application of DC power systems, due to the rapid growth of fault currents in DC transmission and distribution systems, achieving rapid fault isolation and recovery has become the key to ensuring the safe and stable operation of the system. Currently, commonly used DC circuit breakers include mechanical DC circuit breakers, hybrid DC circuit breakers, and all-solid-state DC circuit breakers, etc.

[0003] In mechanical DC circuit breakers, passive oscillation technology and active oscillation technology are the main technical means. However, because mechanical DC circuit breakers need to use large-capacity capacitors, their equipment volume is large, it takes a long time to break small currents, and there are risks of switch zero-crossing re-ignition and system oscillation that may be caused during the turn-off process, which will pose potential safety hazards to the normal operation of the system and other equipment.

[0004] Hybrid DC circuit breakers combine the advantages of mechanical switches and power electronics technology, and achieve controllable turn-off of current through power electronic devices, with characteristics such as arc-free and fast reclosing. However, their turn-off current technical performance and equipment economic performance are restricted by fully controlled power electronic devices, which will bring certain difficulties to the large-scale application of hybrid DC circuit breakers in future high-voltage DC transmission systems.

[0005] Patent CN108475595A proposes a DC circuit breaker based on the principle of LC active resonance, which can effectively solve problems such as large mechanical switch re-ignition risk, long small-current turn-off time, significant oscillation with the system, and high equipment cost in the existing technology. However, it still has defects in closing / reclosing operations, and an additional discharge circuit needs to be added or it is required that the mechanical switch can withstand a large closing inrush current.

[0006] The above information disclosed in the background art section is only used to enhance the understanding of the background of this application. Therefore, it may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

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

[0008] According to the first aspect of the present application, at least one embodiment of the present application provides a current breaking device, comprising: a main branch, the main branch includes n groups of current-carrying units connected in series, where n is an integer greater than or equal to 2; a transfer branch, the transfer branch is connected in parallel with the main branch, and the transfer branch includes n groups of oscillating capacitor units connected in series; an isolation branch, the isolation branch is connected in series with the main branch; a discharge branch, the discharge branch includes n - 1 groups of discharge units, one end of the i-th group of discharge units is connected to the connection point between the i-th group of current-carrying units and the (i + 1)-th group of current-carrying units, and the other end is connected to the connection point between the i-th group of oscillating capacitor units and the (i + 1)-th group of oscillating capacitor units, i ∈ [1, N]; a power consumption branch, the power consumption branch is connected in parallel with the main branch, or the power consumption branch includes n groups of power consumption units connected in series, the i-th group of power consumption units is connected in parallel with the i-th group of current-carrying units, or the i-th group of power consumption units is connected in parallel with the i-th group of oscillating capacitor units or the internal components of the oscillating capacitor units; an oscillating inductor unit and a power electronics unit, which are connected in series in the parallel loop of the main branch and the transfer branch, the oscillating inductor unit is connected in series inside the main branch or the transfer branch, and the power electronics unit is connected in series inside the main branch or the transfer branch.

[0009] For example, in some embodiments of the present application, the current-carrying unit includes a mechanical switch, or at least two mechanical switches connected in series or in parallel; the oscillating capacitor unit includes an oscillating capacitor, or at least two oscillating capacitors connected in series or in parallel; the isolation branch includes a mechanical switch, or at least two mechanical switches connected in series or in parallel; the discharge unit includes a resistor, or at least two resistors connected in series or in parallel, or includes an inductor, or at least two inductors connected in series or in parallel, or includes at least one group of resistors and inductors connected in series; the power consumption unit includes a non-linear resistor, or at least two non-linear resistors connected in series or in parallel; the oscillating inductor unit includes an oscillating inductor, or at least two oscillating inductors connected in series or in parallel.

[0010] For example, in some embodiments of the present application, the power electronics unit includes a power electronics module or at least two power electronics 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 an external wire is led out, and the negative electrode of the second power electronic switch is connected to the negative electrode of the first voltage source and then an external wire is led out; 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, the negative electrode of the fourth power electronic switch is respectively 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 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 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 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 first-level power semiconductor device, or at least two levels of power semiconductor devices are connected in series or in parallel, where: the power semiconductor device includes a fully controlled power semiconductor device or a semi-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 IGBT, IEGT, IGCT, MOSFET, and GTO; the semi-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-charge 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 control method for a current breaking device as described in any one of the first aspects, including: a. In the case of a fault in the power system, output a tripping command to disconnect the mechanical switch of the main branch; b. When the mechanical switch of the main branch is separated to the insulation separation position, trigger the power electronic unit to output a single pulse or a multi-pulse square wave voltage to excite the oscillation capacitor of the transfer branch and the oscillation inductor of the oscillation inductor unit to oscillate, generating an oscillation current equal in amplitude and opposite in direction to the fault current amplitude, and the oscillation current causes the mechanical switch of the main branch to turn off at the zero crossing; c. Corresponding to the situation where the mechanical switch of the main branch turns off at the zero crossing, the fault current charges the oscillation capacitor of the transfer branch, and when the voltage across the oscillation capacitor is greater than the operating voltage of the energy dissipation branch, the fault current is transferred to the energy dissipation branch and dissipated to zero; d. Open the mechanical switch of the isolation branch; e. Gradually close the mechanical switch of the main branch to enable the oscillation capacitor of the transfer branch to discharge through the resistor and / or inductor of the discharge branch; f. Output a reclosing command to close the mechanical switch of the isolation branch; g. In the case where the current breaking device is reclosed to the faulty power system, re-execute step a.

[0016] For example, in some embodiments of the present application, it further includes: in the case where the power system does not have a fault, the mechanical switch of the main branch is in the closed state, and the mechanical switch of the isolation branch is in the closed state.

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

[0018] A current breaking device and its control method provided by the present application, when the current breaking device trips, by controlling the operating states of the internal components of the main branch and the transfer branch, enables the transfer branch to generate an oscillation current equal in amplitude and opposite in direction to the fault current, so that the main branch can be reliably turned off, overcoming problems such as a large risk of mechanical switch restrike, a long small current turn-off time, significant oscillation with the system, and high equipment costs, which is conducive to large-scale popularization and application in AC and DC power transmission and distribution systems; through the gradual closing of multiple groups of mechanical switches of the main branch, the energy release of the oscillation capacitor during the previous tripping operation is realized, effectively reducing the magnitude of the inrush current during closing / reclosing and improving the service life of the mechanical switch.

[0019] It should be understood that the above general description and the following detailed description are only exemplary and do not limit the present application. Description of the Drawings

[0020] The above and other objects, features, and advantages of the present application will become more apparent by describing its exemplary embodiments in detail with reference to the accompanying drawings. The accompanying drawings described below are only some embodiments of the present application and do not limit the present application.

[0021] Figure 1 Shows the first embodiment of an exemplary current interruption device;

[0022] Figure 2 Shows the second embodiment of an exemplary current interruption device;

[0023] Figure 3 Shows the third embodiment of an exemplary current interruption device;

[0024] Figure 4 Shows the fourth embodiment of an exemplary current interruption device;

[0025] Figure 5 Shows the fifth embodiment of an exemplary current interruption device;

[0026] Figure 6 Shows the sixth embodiment of an exemplary current interruption device;

[0027] Figure 7A Shows the first embodiment of an exemplary power electronic module;

[0028] Figure 7B Shows the second embodiment of an exemplary power electronic module;

[0029] Figure 7C Shows the third embodiment of an exemplary power electronic module;

[0030] Figure 8 Shows the flowchart of the control method of an exemplary current interruption device;

[0031] Figure 9A Shows the first embodiment of the circuit structure diagram of an exemplary passive power electronic module;

[0032] Figure 9B Shows the second embodiment of the circuit structure diagram of an exemplary passive power electronic module;

[0033] Figure 9C Shows the third embodiment of the circuit structure diagram of an exemplary passive power electronic module;

[0034] Figure 9D Shows the fourth embodiment of the circuit structure diagram of an exemplary passive power electronic module;

[0035] Figure 10A Shows the first embodiment of the extended connection schematic diagram of an exemplary current interruption device;

[0036] Figure 10B Example 2 showing an extended connection schematic diagram of an exemplary current breaking device;

[0037] Figure 10C Example 3 showing an extended connection schematic diagram of an exemplary current breaking device. Detailed implementation manners

[0038] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various 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 thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. Identical reference numerals in the figures denote identical or similar parts, and thus their repeated description will be omitted.

[0039] The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of the embodiments of the present disclosure. However, those skilled in the art will realize that the technical solutions of the present disclosure can be practiced without one or more of these specific details, or can be implemented in other ways, components, materials, devices, etc. In these cases, well-known structures, methods, devices, implementations, materials, or operations will not be shown or described in detail.

[0040] The flowcharts shown in the accompanying drawings are merely illustrative and not necessarily include all the contents and operations or steps, nor are they necessarily executed in the described order. For example, some operations or steps can be decomposed, while some operations or steps can be combined or partially combined, so the actual execution order may be changed according to the actual situation.

[0041] The terms "first", "second", etc. in the description and claims of this application and the above-mentioned accompanying drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. 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 further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products, or devices.

[0042] Those skilled in the art can understand that the accompanying drawings are only schematic diagrams of the example embodiments, and the modules or processes in the drawings are not necessarily essential for implementing this application, so they cannot be used to limit the protection scope of this application.

[0043] Figure 1 Example 1 showing an exemplary current breaking device.

[0044] As shown Figure 1 in the figure, the current breaking device includes a main branch (1), a transfer branch (2), a power consumption branch (3), a discharge branch (4) and an isolation branch (5).

[0045] Among them, the main branch (1) is connected in parallel with the transfer branch (2), and the parallel connection point is O 1 and O 2 .

[0046] The main branch (1) includes n groups of current-carrying units connected in series, where n is an integer greater than or equal to 2. From the parallel connection point O 1 to the parallel connection point O 2 , the directions are the first group of current-carrying units (11), the second group (12) of current-carrying units,..., the i-th group of current-carrying units (1i),..., the n-th group of current-carrying units (1n).

[0047] The transfer branch (2) includes n groups of oscillating capacitor units connected in series. From the parallel connection point O 1 to the parallel connection point O 2 , the directions are the first group of oscillating capacitor units (21), the second group of oscillating capacitor units (22),..., the i-th group of oscillating capacitor units (2i),..., the n-th group of oscillating capacitor units (2n).

[0048] The power consumption branch (3) is connected in parallel with the main branch (1).

[0049] The discharge branch (4) includes n - 1 groups of discharge units. One end of the i-th group of discharge units (4i) is connected to the connection point between the i-th group of current-carrying units (1i) and the (i + 1)-th group of current-carrying units (1(i + 1)), and the other end is connected to the connection point between the i-th group of oscillating capacitor units (2i) and the (i + 1)-th group of oscillating capacitor units (2(i + 1)), where i is an integer from 1 to N.

[0050] The isolation branch (5) is connected in series with the main branch (1).

[0051] Inside the circuit loop where the main branch (1) and the transfer branch (2) are connected in parallel, there is also at least one oscillating inductor unit (212,..., 2i2,..., 2n2), which can be arranged in series inside the current-carrying unit (1i) of the main branch (1) or inside the oscillating capacitor unit (2i) of the transfer branch (2). Figure 1 This is an embodiment where the oscillating inductor unit (2i2) is evenly arranged in each oscillating capacitor unit (2i) inside the transfer branch (2).

[0052] Inside the loop where the main branch (1) and the transfer branch (2) are connected in parallel, there is also at least one group of power electronic units (213,..., 2i3,..., 2n3), which can be arranged in series inside the current-carrying unit of the main branch (1) or inside the oscillating capacitor unit of the transfer branch (2). Figure 1An embodiment in which the power electronic units (2i3) are evenly arranged in each oscillation capacitor unit (2i) inside the transfer branch (2).

[0053] Figure 2 Show the second embodiment of the exemplary current breaking device.

[0054] Figure 2 The shown circuit structure is Figure 1 basically similar to the shown circuit structure, the only difference being that: the energy-consuming branch (3) includes n groups of energy-consuming units (31,..., 3i,..., 3n) connected in series, and the i-th group of energy-consuming units (3i) is connected in parallel with the i-th current-carrying unit (1i).

[0055] Figure 3 Show the third embodiment of the exemplary current breaking device.

[0056] Figure 3 The shown circuit structure is Figure 1 basically similar to the shown circuit structure, the only difference being that: the energy-consuming branch (3) includes n groups of energy-consuming units (31,..., 3i,..., 4n) connected in series, and the i-th group of energy-consuming units (3i) is connected in parallel with the i-th oscillation capacitor unit (2i).

[0057] Figure 4 Show the fourth embodiment of the exemplary current breaking device.

[0058] Figure 4 The shown circuit structure is Figure 1 basically similar to the shown circuit structure, the only difference being that: the energy-consuming branch (3) includes n groups of energy-consuming units (31,..., 3i,..., 3n) connected in series, and the i-th group of energy-consuming units (3i) is connected in parallel with the oscillation capacitor (2i1) and the oscillation inductor unit (2i2) of the i-th oscillation capacitor unit (2i).

[0059] Figure 5 Show the fifth embodiment of the exemplary current breaking device.

[0060] Figure 5 The shown circuit structure is Figure 1 basically similar to the shown circuit structure, the only difference being that: the energy-consuming branch (3) includes n groups of energy-consuming units (31,..., 3i,..., 3n) connected in series, and the i-th group of energy-consuming units (3i) is connected in parallel with the oscillation capacitor (2i1) and the power electronic unit (2i3) of the i-th oscillation capacitor unit (2i).

[0061] Figure 6 Show the sixth embodiment of the exemplary current breaking device.

[0062] Figure 6 The shown circuit structure is Figure 1The circuit structures shown are basically similar, with the only difference being that the energy-consuming branch (3) includes n groups of energy-consuming units (31, …, 3i, …, 3n) connected in series, and the i-th group of energy-consuming units (3i) is connected in parallel with the oscillating capacitor (2i1) of the i-th group of oscillating capacitor units (2i).

[0063] In Figures 1 - 6 the embodiment shown, the current-carrying unit (1i) includes a mechanical switch, or at least two mechanical switches connected in series or in parallel. The oscillating capacitor unit (2i) includes an oscillating capacitor, or at least two oscillating capacitors connected in series or in parallel. The oscillating inductor unit (2i2) includes an oscillating inductor, or at least two oscillating inductors connected in series or in parallel. The energy-consuming unit (3i) includes a non-linear resistor, or at least two non-linear resistors connected in series or in parallel. The discharging unit (4i) includes a resistor, or at least two resistors connected in series or in parallel, or includes an inductor, or at least two inductors connected in series or in parallel, or includes at least one group of resistors and inductors connected in series. The isolation branch (5) includes a mechanical switch, or at least two mechanical switches connected in series or in parallel.

[0064] The mechanical switch is usually a fast-type fast switch, and the principle of the mechanical switch can be electromagnetic repulsion, permanent magnet, explosion, etc. When multiple fast switches are connected in series, an RC circuit is usually connected in parallel beside each fast switch to improve the voltage sharing performance.

[0065] The oscillating capacitor includes a capacitor, or at least two capacitors connected in series or in parallel.

[0066] The oscillating inductor includes an inductor, or at least two inductors connected in series or in parallel.

[0067] The non-linear resistor is usually a zinc oxide arrester.

[0068] The power electronics unit (2i3) includes a power electronics module or at least two power electronics modules connected in series.

[0069] Figure 7A Show Embodiment 1 of an exemplary power electronics module.

[0070] As Figure 7A shown, the power electronics module includes a first power electronics switch 1a, a second power electronics switch 2a, and a first voltage source 1b. Among them, the positive pole of the first power electronics switch 1a is connected to the positive pole of the first voltage source 1b, the negative pole of the first power electronics switch 1a is connected to the positive pole of the second power electronics switch 2a and then an external wire is led out, and the negative pole of the second power electronics switch 2a is connected to the negative pole of the first voltage source 1b and then an external wire is led out.

[0071] Figure 7BShows Embodiment 2 of an exemplary power electronic module.

[0072] As Figure 7B 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. Among them, the positive pole of the third power electronic switch 3a is respectively connected to the positive pole of the fifth power electronic switch 5a and the positive pole of the second voltage source 2b, the negative pole of the fourth power electronic switch 4a is respectively connected to the negative pole of the sixth power electronic switch 6a and the negative pole of the second voltage source 2b, the negative pole of the third power electronic switch 3a is connected to the positive pole of the fourth power electronic switch 4a and then an external connection wire is led out, and the negative pole of the fifth power electronic switch 5a is connected to the positive pole of the sixth power electronic switch 6a and then an external connection wire is led out.

[0073] Figure 7C Shows Embodiment 3 of an exemplary power electronic module.

[0074] As Figure 7C 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 connection wire 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 connection wire is led out.

[0075] 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 first-level power semiconductor device, or at least two-level power semiconductor devices connected in series or in parallel. Among them, the power semiconductor device includes a fully controlled power semiconductor device or a semi-controlled power semiconductor device. The fully controlled power semiconductor device includes at least one of IGBT, IEGT, IGCT, MOSFET, and GTO. The semi-controlled power semiconductor device includes a thyristor.

[0076] 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-charge 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 turn-off process, overvoltage protection measures such as a lightning arrester or a chopper circuit can be connected in parallel at both ends.

[0077] Figure 8 Shows a flowchart of a control method for an exemplary current breaking device.

[0078] When the power system is not faulty, the initial state of the current breaking device is the closed position. Current flows through the main branch (1) and the isolation branch (5). The mechanical switch of the main branch (1) is in the closed state, and the mechanical switch of the isolation branch (5) is in the closed state. The power electronic module in the input mode of the transfer branch (2) is in the blocked state or the removed state. When a fault occurs in the power system, the following opening and reclosing operations are performed.

[0079] In step S701, an opening command is output to open the mechanical switch of the main branch.

[0080] The current breaking device receives the opening command and opens the mechanical switch of the main branch.

[0081] In step S702, when the mechanical switch of the main branch is separated to the insulated opening position, the power electronic unit is triggered to output a single pulse or a multi-pulse square wave voltage to excite the oscillation of the oscillation capacitor and the oscillation inductor of the oscillation inductor unit of the transfer branch, generating an oscillation current equal in amplitude and opposite in direction to the fault current. The oscillation current causes the mechanical switch of the main branch to turn off at the zero crossing.

[0082] According to some embodiments, when the current breaking device is used as a load switch, the load current to be turned off is usually small. The power electronic unit can be designed to output a single pulse, and the pulse frequency is close to the resonance frequency of the oscillation capacitor and the oscillation inductor. The peak value of the generated single pulse current is greater than the amplitude of the load current. When the current breaking device is used as a circuit breaker, the fault current to be turned off is usually large. The power electronic unit can be designed to output multi-pulses, and the pulse frequency is close to the resonance frequency of the oscillation capacitor and the oscillation inductor. The continuously increasing current peak value generated by multiple oscillations is greater than the amplitude of the fault current.

[0083] In step S703, corresponding to the situation where the mechanical switch of the main branch turns off at the 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 energy dissipation branch, the fault current is transferred to the energy dissipation branch and dissipated to zero.

[0084] In step S704, the mechanical switch of the isolation branch is opened.

[0085] According to some embodiments, the step of opening the mechanical switch of the isolation branch can be performed when steps S701, S702, and S703 are executed.

[0086] In step S705, the mechanical switches of the main branch are closed one by one so that the oscillation capacitor of the transfer branch discharges through the resistor and / or inductor of the discharge branch.

[0087] In step S706, a reclosing command is output to close the mechanical switch of the isolation branch.

[0088] In the case where the current breaking device recloses on a faulty power system, the opening operation is performed again, and step S701 is executed again; if the current breaking device recloses on a normal power system, the reclosing is successful.

[0089] For the current breaking device and its control method provided by the present application, when the current breaking device opens, by controlling the operating states of the components inside the main branch and the transfer branch, an oscillating current equal in amplitude and opposite in direction to the fault current is generated in the transfer branch, so that the main branch can be reliably turned off, overcoming problems such as a large risk of mechanical switch restriking, a long turn-off time for small currents, significant oscillation with the power system, and high equipment costs, which is conducive to large-scale popularization and application in AC and DC power transmission and distribution systems; through the sequential closing of multiple groups of mechanical switches in the main branch, the energy stored in the oscillating capacitor during the previous opening operation is released, effectively reducing the magnitude of the inrush current during closing / reclosing and extending the life of the mechanical switch.

[0090] According to some embodiments, the oscillating inductor unit of the embodiments of the present application can also 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-carrying unit. The oscillating inductor arranged in the main branch can be a linear inductor or a saturable inductor.

[0091] According to some embodiments, the power electronic unit of the embodiments of the present application can also be arranged in the main branch. When the power electronic unit can also be arranged in the main branch, in addition to the active power electronic module topology shown in FIG. 7, the power electronic module can also be Figures 9A - 9D the passive power electronic module topology shown.

[0092] Figure 9A FIG. 1 shows a first embodiment of the circuit structure diagram of an exemplary passive power electronic module, including two series-connected power electronic switches and a non-linear resistor connected in parallel at the head and tail.

[0093] Figure 9B FIG. 2 shows a second embodiment of the circuit structure diagram of an exemplary passive power electronic module, including two parallel-connected power electronic switches and a non-linear resistor connected in parallel at the head and tail.

[0094] Figure 9C FIG. 3 shows a third embodiment of the circuit structure diagram of an exemplary passive power electronic module, including four power electronic switches and a non-linear resistor. The four power electronic switches form a full-bridge circuit, and the non-linear resistor is connected in parallel to the DC side of the full-bridge circuit.

[0095] Figure 9DFigure 4 shows an example of the circuit structure diagram of a passive power electronic module, including four diodes, a power electronic switch, and a non-linear resistor. The four diodes form 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 non-linear resistor is connected in parallel to the DC side or the AC side of the full-bridge circuit.

[0096] In this application, multiple current breaking devices can be flexibly expanded by using a modular series connection method, as Figure 10A shown, to meet the application requirements of high-voltage systems or the requirements of engineering compact structure design.

[0097] This application can also flexibly expand the main branch, discharge branch, transfer branch, and energy-consuming branch parts by using a modular series connection method, as Figure 10B shown, to meet the application requirements of high-voltage systems or the requirements of engineering compact structure design.

[0098] This application can also flexibly expand the main branch, discharge branch, and transfer branch by using a modular series connection method, as Figure 10C shown, to meet the application requirements of high-voltage systems or the requirements of engineering compact structure design.

[0099] 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. Instead, based on the teachings of the content disclosed in this application, these principles can be applied to many other embodiments.

[0100] In addition, it should be noted that the above-mentioned drawings are only schematic illustrations of the processes included in the method according to the exemplary embodiments of this application, rather than for limiting purposes. It is easy to understand that the processes shown in the above-mentioned drawings do not indicate or limit the time sequence of these processes. Additionally, it is also easy to understand that these processes can be executed synchronously or asynchronously in, for example, multiple modules.

[0101] The above specifically shows and describes the exemplary embodiments of this application. It should be understood that this application is not limited to the detailed structures, setting methods, or implementation methods described here; instead, this application is intended to cover various modifications and equivalent settings included within the spirit and scope of the appended claims.

Claims

1. A current breaking device, characterized in that: include: A main branch, wherein the main branch includes n groups of flow-through units connected in series, where n is an integer greater than or equal to 2; A transfer branch, the transfer branch is connected in parallel with the main branch, and the transfer branch includes n groups of oscillation capacitor units connected in series; An isolation branch, the isolation branch being connected in series with the main branch; A discharge branch, wherein the discharge branch comprises n-1 groups of discharge units, one end of the discharge unit of the i-th group is connected to a connection point between the current passing unit of the i-th group and the current passing unit of the i+1-th group, and the other end is connected to a connection point between the oscillating capacitor unit of the i-th group and the oscillating capacitor unit of the i+1-th group, i∈[1,N]; An energy consumption branch, wherein the energy consumption branch is connected in parallel with the main branch, or the energy consumption branch comprises n groups of energy consumption units connected in series, the i-th group of energy consumption units is connected in parallel with the i-th group of current-passing units, or the i-th group of energy consumption units is connected in parallel with the i-th group of oscillating capacitor units or internal components of the oscillating capacitor units; The oscillating inductance unit and the power electronic unit are connected in series in the parallel loop of the main branch and the transfer branch. The oscillating inductance unit 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 breaking device according to claim 1, characterized in that: The flow unit includes a mechanical switch, or at least two mechanical switches connected in series or in parallel; The oscillating capacitance unit includes an oscillating capacitor, or at least two oscillating capacitors connected in series or in parallel; The isolation branch includes a mechanical switch, or at least two mechanical switches connected in series or in parallel; The discharge unit comprises a resistor, or at least two resistors connected in series or in parallel, or an inductor, or at least two inductors connected in series or in parallel, or at least one group of resistors and inductors connected in series; The energy consumption unit includes a non-linear resistor, or at least two non-linear resistors connected in series or in parallel; The oscillating inductor unit includes one oscillating inductor, or at least two oscillating inductors connected in series or in parallel.

3. The current breaking 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 breaking 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 breaking 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 half-controlled power semiconductor device.

6. The current breaking 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 breaking device according to claim 4, characterized in that: 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.

8. A method for controlling a current breaking device according to any one of claims 1 to 7, characterized in that: include: a. In the event of a power system failure, output a trip command to disconnect the mechanical switch of the main branch; b. When the mechanical switch of the main branch 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 of the transfer branch and the oscillation inductance of the oscillation inductance unit to oscillate, thereby generating an oscillation current with an amplitude equal to that of the fault current and in an opposite direction, and the oscillation current causes the mechanical switch of the main branch to turn off through zero; c. In response to the mechanical switch of the main branch 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 energy consumption branch, the fault current is transferred to the energy consumption branch and dissipated to zero; d. Open the mechanical switch of the isolation branch; e. Closing the mechanical switches of the main branch in groups one by one, so that the oscillation capacitor of the transfer branch discharges through the resistance and / or inductance of the discharge branch; f. Outputting a reclosing command to close the mechanical switch of the isolation branch; g. When the current disconnecting device is reclosed to the faulty power system, re-execute step a.

9. The control method according to claim 8, characterized in that: Also includes: When no fault occurs in the power system, the mechanical switch of the main branch is in a closed state, and the mechanical switch of the isolation branch is in a closed state.

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

Images