Current removal device, current removal control method and power system
By adopting a parallel branch structure and a variable polarity charging module in the current cut-off device, the problem of increased size and cost of the current cut-off device is solved, the power supply requirements for rapid current cut-off and multiple reclosing are met, and the size and cost of the device are reduced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-03-31
AI Technical Summary
The current cut-off device requires multiple sets of pre-charge capacitors, which leads to a significant increase in device size and cost, and cannot meet the power supply requirements for multiple reclosing operations.
The system employs a parallel structure of the first, second, and third branches, utilizing a capacitor module to pre-store energy and generate transfer current. Combined with a variable polarity charging module and an energy-consuming module, it achieves rapid current transfer and zero-crossing point manufacturing, avoiding the need for additional pre-charging capacitors.
It achieves rapid current cut-off, reduces device size and cost, meets the power supply requirements for multiple reclosing operations, and improves fault current cut-off speed and system safety.
Smart Images
Figure CN121769778A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of power equipment technology, specifically to a current cutoff device, a current cutoff control method, and a power system. Background Technology
[0002] With the continuous development of flexible DC transmission networks, their short-circuit capacity is constantly increasing. Unlike AC current interruption, DC current interruption has no natural zero-crossing point, and the DC short-circuit current rises rapidly. Therefore, rapid disconnection is required when a short-circuit fault occurs to prevent the fault from escalating and causing a chain reaction. As a key networking device for flexible DC transmission, the rapid current disconnection device has experienced rapid development and iteration in recent years.
[0003] To meet the reclosing requirements after a short-circuit fault, especially the power supply requirements for multiple reclosing operations, the relevant current cut-off device needs to be equipped with multiple sets of pre-charge capacitors, which leads to a significant increase in device size and cost, severely weakening its original cost and size advantages. When more reclosing operations are required to meet the rapid restoration of power supply to the line during a short-term DC fault, the mechanical current fast cut-off device needs to be equipped with even more pre-charge capacitors, further increasing its size. Summary of the Invention
[0004] This invention provides a current cut-off device, a current cut-off control method, and a power system, aiming to solve the technical problem that the current cut-off device requires multiple sets of pre-charge capacitors, resulting in a significant increase in device size.
[0005] In a first aspect, embodiments of this application provide a current-cutting device, including a first branch, a second branch, and a third branch connected in parallel; The first branch includes a first switch module for controlling the on / off state of the first branch; The second branch includes an energy-consuming module, which is used to absorb electrical energy and limit the voltage across the current-quick disconnection device; The third branch includes a capacitor module, a reactor module, and a second switch module connected in series, as well as a polarity-variable charging module connected in parallel with the capacitor module; the capacitor module has pre-stored energy for generating a transfer current to transfer current to the first branch; the polarity-variable charging module is used to charge the capacitor module according to the charging polarity adapted to the capacitor module; the reactor module is used to limit the frequency of the transfer current; and the second switch module is used to control the on / off state of the third branch.
[0006] In one embodiment of this application, the polarity variable charging module has an output state and an isolation state. In the output state, the polarity variable charging module is used to output a charging voltage to the capacitor module; in the isolation state, the polarity variable charging module is used to disconnect the charging connection with the capacitor module. The output states include a positive polarity output state and a negative polarity output state. In the positive polarity output state, the variable polarity charging module is used to output a positive polarity charging voltage to the capacitor module. In the negative polarity output state, the variable polarity charging module is used to output a negative polarity charging voltage to the capacitor module.
[0007] In one embodiment of this application, the energy-consuming module includes at least one nonlinear resistor.
[0008] In one embodiment of this application, the polarity variable charging module includes at least one charging unit.
[0009] In one embodiment of this application, the first switch module includes n first mechanical switches connected in series, where n is a positive integer greater than or equal to 1.
[0010] In one embodiment of this application, the first mechanical switch is at least one of a vacuum mechanical switch and a gas mechanical switch, depending on the arc-extinguishing medium of the first mechanical switch. According to the operating mechanism of the first mechanical switch, the first mechanical switch is at least one of electromagnetic repulsion mechanical switch, permanent magnet repulsion mechanical switch, permanent magnet mechanism mechanical switch and motor driven mechanical switch.
[0011] In one embodiment of this application, the first switch module includes m second mechanical switches connected in series, where m is a positive integer greater than or equal to 1.
[0012] In one embodiment of this application, the second mechanical switch is at least one of a vacuum mechanical switch and a gas mechanical switch, depending on the arc-extinguishing medium of the second mechanical switch. According to the operating mechanism of the second mechanical switch, the second mechanical switch is at least one of electromagnetic repulsion mechanical switch, permanent magnet repulsion mechanical switch, permanent magnet mechanism mechanical switch and motor driven mechanical switch.
[0013] Secondly, embodiments of this application also provide a current cut-off control method, applied to the aforementioned current cut-off device, comprising: In response to the current cut-off command, the first switch module controls the first branch to disconnect; the variable charging module enters the isolation state and disconnects the charging connection with the capacitor module. When the second switch module is closed and turned on, the capacitor module releases its pre-stored energy to generate a transfer current, which transfers the current in the first branch to the third branch until the current in the first switch module crosses zero and the arc is extinguished. When the voltage of the capacitor module is greater than the preset voltage value, the second branch is turned on, allowing the energy-consuming module to absorb electrical energy and limiting the voltage across the current cut-off device; after the current of the third branch is completely transferred to the second branch, the second switch module is turned off. Based on the current voltage polarity of the capacitor module, the variable polarity charging module enters the output state and charges the capacitor module with the charging polarity adapted to the capacitor module.
[0014] Thirdly, embodiments of this application also provide a power system including a control module and the aforementioned current interruption device, wherein the control module is connected to the current interruption device.
[0015] The beneficial effects of this application are as follows: This application generates a transfer current by pre-storing energy in the capacitor module, which can quickly transfer the fault current of the first branch to the third branch, realize the current zero crossing point, enable the first switch module to quickly disconnect, and the polarity variable charging module can adaptively switch the charging polarity according to the voltage polarity of the capacitor module, replenish energy after the current is cut off, so that the capacitor module always maintains a high amplitude of energy storage, without the need to configure multiple sets of pre-charge capacitors, which can meet the energy supply requirements of multiple reclosing, and significantly reduce the size of the device. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 This is a schematic diagram of the current cut-off device provided in the embodiments of this application; Figure 2 This is a schematic diagram of the specific structure of the current cutting device provided in the embodiments of this application; Figure 3 This is a schematic diagram of current flowing through the first branch under normal conditions, provided in an embodiment of this application. Figure 4 This is a schematic diagram illustrating the transfer of current from the first branch to the third branch according to an embodiment of this application; Figure 5 This is a schematic diagram illustrating the transfer of current from the first branch to the third branch according to an embodiment of this application; Figure 6This is a schematic diagram of current flowing through the second branch provided in an embodiment of this application; Figure 7 This is a schematic diagram of the current cut-off provided in the embodiments of this application; Figure 8 This is a schematic diagram of the steps of the current cut-off control method provided in the embodiments of this application.
[0018] Explanation of reference numerals in the attached figures: 1. First branch; 11. First switch module; 101. First mechanical switch; 2. Second branch; 21. Energy consumption module; 201. Nonlinear resistor; 3. Third branch; 31. Capacitor module; 301. First capacitor; 32. Reactor module; 302. First reactor; 33. Second switch module; 303. Second mechanical switch; 34. Variable polarity charging module; 304. Charging unit. Detailed Implementation
[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0020] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "positive," and "negative," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.
[0021] like Figure 1 As shown, an embodiment of this application provides a current cutting device, including a first branch 1, a second branch 2 and a third branch 3; the first branch 1, the second branch 2 and the third branch 3 are connected in parallel to each other.
[0022] The first branch 1 includes a first switch module 11, which is used to control the on / off state of the first branch 1.
[0023] In some embodiments, the first switch module 11 includes n first mechanical switches 101 connected in series, where n is a positive integer greater than or equal to 1.
[0024] For example, according to the arc-extinguishing medium of the first mechanical switch 101, the first mechanical switch 101 is at least one of a vacuum mechanical switch and a gas mechanical switch.
[0025] According to the operating mechanism of the first mechanical switch 101, the first mechanical switch 101 is at least one of electromagnetic repulsion mechanical switch, permanent magnet repulsion mechanical switch, permanent magnet mechanism mechanical switch and motor drive mechanical switch.
[0026] Under normal operating conditions of the power system, the first switch module 11 remains in the conducting state, while the second branch 2 and the third branch 3 are both turned off, and the first branch 1 serves as the current path of the power system.
[0027] Under power system fault conditions, the current disconnection device receives the current disconnection command, controls the first switch module 11 to start the disconnection operation, and transfers the current of the first branch 1 during the subsequent current disconnection process, so as to realize the rapid disconnection of the first switch module 11.
[0028] The second branch 2 includes an energy-consuming module 21, which is used to absorb electrical energy and limit the current to quickly cut off the voltage at both ends of the device.
[0029] In some embodiments, the second branch 2 is turned on when the voltage of the third branch 3 exceeds the operating threshold of the energy-consuming module 21, in order to transfer the current of the third branch 3. The energy absorbed by the energy-consuming module 21 refers to the consumption of current energy during the transfer process.
[0030] In some embodiments, the power consumption module 21 includes at least one nonlinear resistor 201.
[0031] The third branch 3 includes a capacitor module 31, a reactor module 32, and a second switch module 33 connected in series, as well as a polarity-variable charging module 34 connected in parallel with the capacitor module 31. The capacitor module 31 has pre-stored energy for generating a transfer current to transfer current to the first branch 1. The polarity-variable charging module 34 is used to charge the capacitor module 31 according to the charging polarity adapted to the capacitor module 31. The reactor module 32 is used to limit the frequency of the transfer current. The second switch module 33 is used to control the on / off state of the third branch 3.
[0032] The capacitor module 31 of this application pre-stores electrical energy and releases the pre-stored electrical energy during power system faults, generating a transfer current to gradually transfer the fault current of the first branch 1 to the third branch 3, thus creating a current zero point for the first switch module 11 of the first branch 1. The reactor module 32 is used to limit the frequency of the transfer current.
[0033] In some embodiments, the polarity variable charging module 34 has an output state and an isolation state. In the output state, the polarity variable charging module 34 is used to output a charging voltage to the capacitor module 31. In the isolation state, the polarity variable charging module 34 is used to disconnect the charging connection with the capacitor module 31.
[0034] The output states include positive polarity output state and negative polarity output state. In the positive polarity output state, the variable polarity charging module 34 is used to output a positive polarity charging voltage to the capacitor module 31. In the negative polarity output state, the variable polarity charging module 34 is used to output a negative polarity charging voltage to the capacitor module 31.
[0035] After the current is cut off, the voltage polarity of the capacitor module 31 will reverse. Based on the polarity of the capacitor module 31 after the reversal, the polarity of the variable charging module 34 is matched with the polarity of the capacitor module 31 to replenish the capacitor module 31 and maintain its high-amplitude energy storage.
[0036] In some embodiments, the capacitor module 31 includes a plurality of first capacitors 301, and the reactor module 32 includes a plurality of first reactors 302.
[0037] In some embodiments, the polarity-variable charging module 34 includes at least one charging unit 304. Exemplarily, the charging power supply may be one of a DC-DC converter, a polarity-reversible controllable power supply, a bipolar energy storage charging unit 304, and a bidirectional charging power supply with isolation function.
[0038] In some embodiments, the first switch module 11 includes m second mechanical switches 303 connected in series, where m is a positive integer greater than or equal to 1.
[0039] According to the arc-extinguishing medium of the second mechanical switch 303, the second mechanical switch 303 is at least one of a vacuum mechanical switch and a gas mechanical switch.
[0040] According to the operating mechanism of the second mechanical switch 303, the second mechanical switch 303 is at least one of electromagnetic repulsion mechanical switch, permanent magnet repulsion mechanical switch, permanent magnet mechanism mechanical switch and motor driven mechanical switch.
[0041] like Figure 2 As shown, taking the first switch module 11 including a first mechanical switch 101, the energy consumption module 21 including a nonlinear resistor 201, the capacitor module 31 including a first capacitor 301, the reactor module 32 including a first reactor 302, the second switch module 33 including a second mechanical switch 303, and the polarity variable charging module 34 including a charging unit 304 as examples, the operating principle of the current cut-off device under power system fault conditions is explained in detail.
[0042] It should be noted that the specific components of the current rapid cut-off device are not limited to the units, devices or parts shown in the figure. Moreover, depending on actual needs, the number of each unit, device or part can be one or more.
[0043] For example, Figure 2 In the figures, the first mechanical switch 101, nonlinear resistor 201, first capacitor 301, first reactor 302, second mechanical switch 303, and charging unit 304 are shown as a single unit. However, it is understood that this is merely a simplification or schematic representation for the purpose of illustrating the technical solution of this application. That is, in order to highlight the inventive concept and innovation of this application, some technical details have been omitted from the figures. It is understood that those skilled in the art, based on the inventive concept, will be able to recognize these technical details and know how to apply them to the technical solution of this application.
[0044] like Figure 3 As shown, under normal operating conditions of the power system, the first branch 1 is single-path conducting, the first mechanical switch 101 remains closed, the first branch 1 is the only current path, and all system current flows through the first branch 1; the second branch 2 and the third branch 3 are disconnected, the nonlinear resistor 201 of the second branch 2 is not triggered, and the second mechanical switch 303 remains open.
[0045] The system current flows into the first branch 1 only from the input terminal of the current cut-off device, and flows out from the output terminal after passing through the first mechanical switch 101. No current flows through the second branch 2 and the third branch 3.
[0046] like Figure 4 As shown, after a fault occurs, i.e. under power system fault conditions, the current cut-off process is initiated. The current cut-off device receives the current cut-off command, and the first mechanical switch 101 responds to the current cut-off command by performing a disconnection action. At this time, an arc is ignited between the contacts of the first mechanical switch 101, and the first branch 1 is still in the conducting state.
[0047] The second mechanical switch 303 is closed and conduction is achieved, forming a circuit in the third branch 3. The first capacitor 301 has pre-stored electrical energy, and the charging unit 304 is in an isolated state, i.e., disconnected from the first capacitor 301. In this embodiment, the first terminal of the first capacitor 301 is negative, and the second terminal is positive. Of course, in other embodiments, the second terminal of the first capacitor 301 may be negative, and the first terminal may be positive. This does not affect the discharge of the first capacitor 301. The first capacitor 301 will generate a current in the third branch 3 that is complementary to the direction of the fault current in the first branch 1, gradually diverting the current in the first branch 1.
[0048] Because of the pre-charge voltage, the first capacitor 301 generates a transfer current through the circuit formed by the first reactor 302, the second mechanical switch 303, and the first mechanical switch 101, transferring the current from the first branch 1 to the third branch 3. When the current in the first branch 1 has completely transferred to the third branch 3, the current in the first mechanical switch 101 of the first branch 1 crosses zero and the arc is extinguished. It should be noted that at this time, the second mechanical switch 303 is still in the conducting state, and the charging unit 304 is in the isolated state, that is, the charging unit 304 does not charge the first capacitor 301.
[0049] When the amplitude of the transfer current is equal to the amplitude of the fault current in the first branch 1, the current in the first branch 1 will be completely canceled out, resulting in a zero-current state. At this time, no current flows between the contacts of the first mechanical switch 101, the arc is extinguished naturally, the arc is extinguished and the first branch 1 is completely disconnected.
[0050] This application utilizes the synergistic effect of the first branch 1 and the third branch 3 to generate a transfer current by pre-storing energy in the first capacitor 301. This allows the fault current in the first branch 1 to be quickly transferred to the third branch 3, artificially creating a current zero-crossing point. This enables the first switch module 11 to quickly disconnect, effectively solving the technical problem of DC current not having a natural zero-crossing point, significantly improving the fault current clearing speed, and ensuring system safety.
[0051] like Figure 5 As shown, the capacitor initially discharges with its first terminal exhibiting negative polarity and its second terminal exhibiting positive polarity, generating a transfer current that transfers the current in the first branch 1 to the third branch 3. When the first mechanical switch 101 is disconnected, the transfer current in the third branch 3 does not disappear instantaneously; the remaining energy of the system continues to flow through the third branch 3 loop, reversing the charge on the first capacitor 301. The reverse charging current gradually cancels out the initial polarity voltage of the capacitor, causing the polarity of the capacitor to reverse, making its first terminal positive and its second terminal negative. Furthermore, after the polarity reversal, the voltage across the first capacitor 301 continuously increases, while the current in the third branch 3 continuously decreases.
[0052] At this time, the second mechanical switch 303 remains on, and the charging unit 304 is in an isolated state. That is, the charging unit 304 does not charge the first capacitor 301, and the voltage of the first capacitor 301 continues to increase. Maintaining isolation at this time prevents the charging unit 304 from conflicting with the current reverse polarity of the first capacitor 301, which would cause energy to be canceled out and prevent the voltage of the first capacitor 301 from continuously increasing; it also allows the capacitor to continue receiving the remaining energy from the system, ensuring that the voltage continues to increase.
[0053] like Figure 6As shown, with the continuous transfer of current, the total voltage of the third branch 3 increases rapidly. When the total voltage of the third branch 3 exceeds the operating voltage of the nonlinear resistor 201, the nonlinear resistor 201 of the second branch 2 conducts, absorbing system energy and converting the current energy into heat energy for consumption, while also limiting the voltage across the current cut-off device. After the current has completely transferred to the second branch 2, it controls the second mechanical switch 303 to open.
[0054] After the current interruption process ends, the voltage polarity of the first capacitor 301 has reversed from its initial state of negative polarity at the first end and positive polarity at the second end to positive polarity at the first end and negative polarity at the second end. The power system detects the current voltage polarity of the capacitor module 31 and determines whether its current voltage polarity matches that of the variable polarity charging module 34. If they do not match, the output polarity of the variable polarity charging module 34 is changed to match that of the capacitor module 31. After the polarity of the variable polarity charging module 34 is switched to match that of the capacitor module 31, the variable polarity charging module 34 charges the capacitor module 31 with the charging polarity adapted to the capacitor module 31. This avoids energy cancellation caused by opposite polarities and can quickly replenish the capacitor voltage amplitude to a preset high value, equivalent to the initial pre-charge voltage.
[0055] By replenishing the capacitor module 31 with the polarity-variable charging module 34, the current cut-off device can achieve energy storage cycle reuse without the need to add an additional capacitor bank. If reclosing occurs and a fault is detected again, the capacitor module 31 will still maintain a high amplitude voltage and can directly release the stored energy to generate transfer current, repeating the previous current cut-off process.
[0056] Figure 7 In this process, since the voltage of the first capacitor 301 is opposite to its initial charging polarity, the output polarity of the charging unit 304 needs to be reversed to maintain the output polarity of the charging unit 304 consistent with the voltage polarity of the first capacitor 301. Thus, the current rapid disconnection device provided by this invention can actively determine the voltage polarity of the first capacitor 301 after the interruption is completed and control the output polarity of the charging unit 304 to be consistent with the voltage polarity of the first capacitor 301, ensuring that the voltage amplitude of the first capacitor 301 remains at a relatively high value. This prevents the process where the voltage of the first capacitor 301 continuously decreases and reverses charging due to the opposite polarity of the output polarity of the charging unit 304 and the voltage polarity of the first capacitor 301. The high-amplitude capacitor voltage on the first capacitor 301 is used for rapid current disconnection during subsequent reclosing operations.
[0057] The polarity-variable charging module 34 can adaptively switch the charging polarity according to the voltage polarity of the capacitor module 31, and replenish energy after the current is cut off, so that the capacitor module 31 always maintains a high amplitude of energy storage. Therefore, this application does not need to configure multiple sets of pre-charge capacitors to meet the energy supply requirements of multiple reclosing, which significantly reduces the size and manufacturing cost of the current cut-off device.
[0058] Embodiments of this application also provide a current cut-off control method, applied to the current cut-off device in the above embodiments, such as... Figure 8 As shown, it includes: In step S1, in response to the current cut-off command, the first switch module 11 controls the first branch 1 to disconnect; the variable charging module enters the isolation state and disconnects the charging connection with the capacitor module 31.
[0059] In step S2, the second switch module 33 closes and conducts, and the capacitor module 31 releases the pre-stored energy to generate a transfer current, causing the current in the first branch 1 to transfer to the third branch 3, until the current in the first switch module 11 crosses zero and the arc is extinguished.
[0060] In step S3, when the voltage of capacitor module 31 is greater than the preset voltage value, the second branch 2 is turned on, so that the energy-consuming module 21 absorbs electrical energy and limits the voltage at both ends of the current cut-off device; after the current of the third branch 3 is completely transferred to the second branch 2, the second switch module 33 is turned off.
[0061] Step S4: Detect the current voltage polarity of capacitor module 31 and determine whether the current voltage polarity of capacitor module 31 is consistent with the polarity of variable polarity charging module 34. If they are consistent, proceed to step S6; if they are inconsistent, proceed to step S5.
[0062] Step S5: Change the output polarity of the variable polarity charging module 34 to correspond to the current voltage polarity of the capacitor module 31.
[0063] In step S6, the polarity-variable charging module 34 charges the capacitor module 31 with a charging polarity adapted to the capacitor module 31.
[0064] After receiving the current cut-off command, the first switch module 11 of this application performs a disconnection operation according to the current cut-off command.
[0065] The current cut-off device or external power system controls the second switch module 33 to close, generating a transfer current, and the current in the first branch 1 is transferred to the third branch 3. For example... Figure 4As shown, after the second mechanical switch 303 is closed, the first capacitor 301, due to the pre-charge voltage, generates a transfer current through the circuit of the first reactor 302, the second mechanical switch 303, and the first mechanical switch 101, transferring the current from the first branch 1 to the third branch 3. When the current in the first branch 1 has completely transferred to the third branch 3, the current in the first mechanical switch 101 of the first branch 1 crosses zero and the arc is extinguished.
[0066] When the total voltage of the third branch 3 exceeds the operating voltage of the nonlinear resistor 201, the second branch 2 conducts. The nonlinear resistor 201 absorbs system energy, converting current energy into heat energy for consumption, and limits the voltage across the current cutoff device to prevent damage to components due to voltage surges. After the current is completely transferred to the second branch 2, it controls the second mechanical switch 303 to open. Regardless of the current magnitude in the circuit, the current cutoff device can achieve rapid interruption across the entire current range. Simultaneously, the capacitor module 31 is recharged by the polarity-variable charging module 34, ensuring that the capacitor module 31 always maintains a high level of stored energy. The voltage on the capacitor module 31 can be used for multiple current interruptions during subsequent reclosing.
[0067] Embodiments of this application also provide a power system, including a control module and the current interruption device described in the above embodiments, wherein the control module is connected to the current interruption device.
[0068] In some embodiments, the power system further includes a polarity detection unit for detecting the current voltage polarity of the capacitor module 31.
[0069] The foregoing has provided a detailed description of a current cut-off device, a current cut-off control method, and a power system provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.
Claims
1. A current-cutting device, characterized in that, This includes the first, second, and third branches that are connected in parallel; The first branch includes a first switch module for controlling the on / off state of the first branch; The second branch includes an energy-consuming module, which is used to absorb electrical energy and limit the voltage across the current-quick disconnection device; The third branch includes a capacitor module, a reactor module, and a second switch module connected in series, as well as a polarity variable charging module connected in parallel with the capacitor module; the capacitor module has pre-stored energy for generating transfer current to transfer current to the first branch. The variable polarity charging module is used to charge the capacitor module according to the charging polarity adapted to the capacitor module; the reactor module is used to limit the frequency of the transfer current; The second switch module is used to control the on / off state of the third branch.
2. The current-cutting device according to claim 1, characterized in that, The polarity-variable charging module has an output state and an isolation state; in the output state, the polarity-variable charging module is used to charge the capacitor module; in the isolation state, the polarity-variable charging module disconnects the charging connection with the capacitor module. The output states include a positive polarity output state and a negative polarity output state. In the positive polarity output state, the variable polarity charging module is used to output a positive polarity charging voltage to the capacitor module. In the negative polarity output state, the variable polarity charging module is used to output a negative polarity charging voltage to the capacitor module.
3. The current-cutting device according to claim 1, characterized in that, The energy-consuming module includes at least one nonlinear resistor.
4. The current-cutting device according to claim 1, characterized in that, The polarity-variable charging module includes at least one charging unit.
5. The current interruption device according to claim 1, characterized in that, The first switch module includes n first mechanical switches connected in series, where n is a positive integer greater than or equal to 1.
6. The current interruption device according to claim 5, characterized in that, According to the arc-extinguishing medium of the first mechanical switch, the first mechanical switch is at least one of a vacuum mechanical switch and a gas mechanical switch; According to the operating mechanism of the first mechanical switch, the first mechanical switch is at least one of electromagnetic repulsion mechanical switch, permanent magnet repulsion mechanical switch, permanent magnet mechanism mechanical switch and motor driven mechanical switch.
7. The current interruption device according to claim 1, characterized in that, The second switch module includes m second mechanical switches connected in series, where m is a positive integer greater than or equal to 1.
8. The current-cutting device according to claim 7, characterized in that, According to the arc-extinguishing medium of the second mechanical switch, the second mechanical switch is at least one of a vacuum mechanical switch and a gas mechanical switch; According to the operating mechanism of the second mechanical switch, the second mechanical switch is at least one of electromagnetic repulsion mechanical switch, permanent magnet repulsion mechanical switch, permanent magnet mechanism mechanical switch and motor driven mechanical switch.
9. A current cutoff control method, applied to the current cutoff device as described in any one of claims 1-8, characterized in that, include: In response to the current cut-off command, the first switch module controls the first branch to disconnect; The variable charging module enters isolation mode, disconnecting the charging connection with the capacitor module; When the second switch module is closed and turned on, the capacitor module releases its pre-stored energy to generate a transfer current, which transfers the current in the first branch to the third branch until the current in the first switch module crosses zero and the arc is extinguished. When the voltage of the capacitor module is greater than the preset voltage value, the second branch is turned on, allowing the energy-consuming module to absorb electrical energy and limiting the voltage across the current cut-off device. After the current in the third branch is completely transferred to the second branch, the second switch module is tripped and turned off. Based on the current voltage polarity of the capacitor module, the variable polarity charging module enters the output state and charges the capacitor module with the charging polarity adapted to the capacitor module.
10. An electric power system, characterized in that, It includes a control module and a current-cutting device as described in any one of claims 1-8, wherein the control module is connected to the current-cutting device.