Circuit breaker and insulation recovery circuit thereof

Abstract

The invention relates to a circuit breaker and an insulation recovery circuit thereof. The insulation recovery circuit comprises a control module, a current guiding module and a commutation trigger module. The control module is used for controlling the vacuum switch to be switched off and controlling the current guiding module to be switched on under the condition that the current of the circuit breaker is switched off, and the first commutation trigger unit and the second commutation trigger unit are both used for changing the voltage difference between the two ends of the current guiding module so as to guide abnormal current flowing through the vacuum switch to the current guiding module; the control module is also used for controlling the current guiding module to generate current zero crossing so as to enable the current guiding module to be disconnected, and controlling the vacuum switch to be connected under the condition of zero voltage. According to the invention, the abnormal current flowing through the vacuum switch is converted to the current guiding module, so that the abnormal current flowing through the vacuum switch is reduced, the arcing time of the vacuum switch is reduced, the zero-voltage recovery time of the vacuum switch is prolonged, the insulation recovery speed of the vacuum switch is improved, and the insulation recovery capability of the vacuum switch is enhanced.

Description

Technical Field

[0001] This disclosure relates to the field of power system fault protection technology, and in particular to a circuit breaker and its insulation restoration circuit. Background Technology

[0002] In flexible DC transmission systems, DC circuit breakers serve as critical anomaly isolation devices, and their breaking performance directly impacts the system's safety and stability. When a short-circuit anomaly occurs, the DC circuit breaker plays a vital role in rapidly disconnecting the circuit and achieving anomaly isolation. However, during the current interruption process of a DC circuit breaker, the vacuum switch (VS) is subjected to significant electrical stress, which affects its insulation recovery capability after the current crosses zero. Therefore, improving the insulation recovery capability of vacuum switches has become a crucial technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0003] In order to solve the above-mentioned technical problems, or at least partially solve the above-mentioned technical problems, this disclosure provides a circuit breaker and its insulation recovery circuit, which can improve the insulation recovery speed of vacuum switches, thereby improving the insulation recovery capability of vacuum switches.

[0004] This disclosure provides an insulation restoration circuit for a circuit breaker, the insulation restoration circuit including: a control module, a current guiding module and a commutation triggering module;

[0005] The control module is connected to the control terminal of the vacuum switch;

[0006] The current guiding module and the vacuum switch are located in different branches, and the control terminal of the current guiding module is connected to the control module.

[0007] The commutation triggering module includes a first commutation triggering unit and / or a second commutation triggering unit; the first commutation triggering unit is connected in series with the current guiding module, the control terminal of the second commutation triggering unit is connected to the control module, and the second commutation triggering unit is connected in series with the vacuum switch;

[0008] The control module is used to control the vacuum switch to open and the current guiding module to close when the circuit breaker interrupts current. The first commutation trigger unit and the second commutation trigger unit are both used to change the voltage difference across the current guiding module so as to guide the abnormal current flowing through the vacuum switch to the current guiding module. The control module is also used to control the current guiding module to cross zero so as to open the current guiding module and control the vacuum switch to close under zero voltage.

[0009] Optionally, the current-guided module includes multiple vacuum-triggered switches;

[0010] Multiple vacuum trigger switches are connected in series, and the control terminals of all vacuum trigger switches are connected to the control module.

[0011] The vacuum trigger switch is used to turn on when a turn-on signal is received from the control module.

[0012] Optionally, the first commutation trigger unit includes an energy storage device and a pre-charging circuit;

[0013] The energy storage device is connected in series with the current guiding module. The pre-charging circuit is used to charge the energy storage device. The pre-charging circuit stops charging in response to the charging stop signal sent by the control module. The energy storage device is used to change the voltage difference across the current guiding module when the current guiding module is turned on.

[0014] Optionally, the energy storage device includes a first capacitor; the first capacitor is connected in series with the current guiding module, and a pre-charging circuit is used to charge the first capacitor.

[0015] Optionally, the second commutation trigger unit includes a first switch and / or a second switch;

[0016] The control terminals of both the first and second switches are connected to the control module.

[0017] The first switch is connected in series with the vacuum switch.

[0018] or,

[0019] The second switch is connected in series with the vacuum switch.

[0020] or,

[0021] Both the first switch and the second switch are connected in series with the vacuum switch;

[0022] Both the first switch and the second switch are used to disconnect the circuit breaker when the control module determines that a current interruption has occurred; one of the first switch and the second switch includes a power electronic switch and the other includes a high-arc voltage mechanical switch.

[0023] Optionally, the first switch includes a power electronic switch; the second switch includes a high-arc voltage mechanical switch.

[0024] The control terminal of the power electronic switch is connected to the control module, and the power electronic switch is connected in series with the vacuum switch.

[0025] The control terminal of the high-arc voltage mechanical switch is connected to the control module, and the high-arc voltage mechanical switch is connected in series with the vacuum switch.

[0026] Optionally, the unidirectional topology of the power electronic switch includes any one of an insulated gate bipolar transistor, an integrated gate commutated thyristor, and a gate injection enhancement transistor.

[0027] Optionally, the bidirectional topology of the power electronic switch includes any one of the following: anti-series structure, full-bridge structure, and diode bridge structure.

[0028] Optionally, at the first moment, the control module controls the vacuum switch to open and the current guiding module to turn on; the commutation trigger module is used to change the voltage difference across the current guiding module to guide the abnormal current flowing through the vacuum switch to the current guiding module between the first moment and the second moment; wherein, the first moment is the moment when the circuit breaker interrupts the current.

[0029] At the second moment, the vacuum switch is in a zero-current state, and all abnormal current flowing through the vacuum switch is guided to the current guiding module.

[0030] At the third moment, the current guiding module controls the current guiding module to cause the current to cross zero so that the current guiding module is disconnected, and after the third moment, it controls the vacuum switch to conduct under zero voltage.

[0031] This disclosure also provides a circuit breaker including any insulation restoration circuit as described above and a vacuum switch.

[0032] This disclosure provides a circuit breaker and its insulation restoration circuit. The circuit breaker includes a control module, a current guiding module, and a commutation trigger module. The commutation trigger module includes a first commutation trigger unit and / or a second commutation trigger unit. The insulation restoration circuit can simultaneously include both the first and second commutation trigger units, or it can include the first and second commutation trigger units separately. The control module is connected to the control terminal of the vacuum switch and the control terminal of the current guiding module. The current guiding module and the vacuum switch are located in different branches. The first commutation trigger unit and the current guiding module are connected in series in the same branch. The second commutation trigger unit and the vacuum switch are connected in series in the same branch, and the control terminal of the second commutation trigger unit is connected to the control module. The control module detects the current interruption status of the circuit breaker. When a current interruption occurs, the control module controls the vacuum switch to open and the current guiding module to close. Even when the vacuum switch is open, current still exists due to arcing. At this time, the first and second commutation trigger units create a voltage difference across the closed current guiding module, thus guiding the abnormal current flowing through the vacuum switch to the current guiding module. This reduces the abnormal current flowing through the vacuum switch, thereby shortening the arcing duration and extending the zero-voltage recovery time, ultimately improving the insulation recovery speed and enhancing the insulation recovery capability of the vacuum switch. The control module also controls the current guiding module to achieve zero-current crossing. After the current crosses zero, the current guiding module naturally turns off until there is no current in the entire circuit. Then, the control module controls the vacuum switch to close again, thus achieving insulation recovery of the entire circuit breaker. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the 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.

[0034] Figure 1 This is a schematic diagram of the insulation restoration circuit of a circuit breaker provided in an embodiment of the present disclosure.

[0035] Figure 2 This is a schematic diagram of the insulation restoration circuit of another circuit breaker provided in an embodiment of the present disclosure.

[0036] Figure 3 This is a schematic diagram of the insulation restoration circuit of another circuit breaker provided in an embodiment of the present disclosure.

[0037] Figure 4 This disclosure provides a schematic diagram of the structure of a current guiding module.

[0038] Figure 5 This disclosure provides a schematic diagram of the structure of an insulation restoration circuit for another circuit breaker.

[0039] Figure 6 A schematic diagram of the insulation restoration circuit of another circuit breaker provided in this disclosure.

[0040] Figure 7 A schematic diagram of the insulation restoration circuit of another circuit breaker provided in this disclosure.

[0041] Figure 8 This is a schematic diagram of an anti-series structure of a power electronic switch provided in an embodiment of this disclosure.

[0042] Figure 9 This is a schematic diagram of a full-bridge structure of a power electronic switch provided in an embodiment of this disclosure.

[0043] Figure 10 This is a schematic diagram of a diode bridge structure for a power electronic switch provided in an embodiment of this disclosure.

[0044] Figure 11 This is a schematic diagram illustrating the current changes within a vacuum switch and current guiding module, as provided in an embodiment of this disclosure. Detailed Implementation

[0045] The features and exemplary embodiments of various aspects of this application will now be described in detail. Numerous specific details are set forth in the following detailed description in order to provide a comprehensive understanding of this application. However, it will be apparent to those skilled in the art that this application can be implemented without some of these specific details. The following description of embodiments is merely intended to provide a better understanding of this application by illustrating examples thereof.

[0046] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The embodiments will now be described in detail with reference to the accompanying drawings.

[0047] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0048] It should be understood that when describing the structure of a component, when referring to a layer or region as being "above" or "on top of" another layer or region, it can mean that it is directly above the other layer or region, or that it contains other layers or regions between it and the other layer or region. Furthermore, if the component is flipped over, that layer or region will be located "below" or "under" the other layer or region.

[0049] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0050] In the embodiments of this application, the term "electrical connection" can refer to a direct electrical connection between two components, or it can refer to an electrical connection between two components via one or more other components.

[0051] In the embodiments of this application, the first node, the second node, and the third node are defined only for the convenience of describing the circuit structure, and the first node, the second node, and the third node are not actual circuit units.

[0052] Various modifications and variations can be made to this application without departing from its spirit or scope, which will be apparent to those skilled in the art. Therefore, this application is intended to cover modifications and variations falling within the scope of the corresponding claims (the claimed technical solutions) and their equivalents. It should be noted that the embodiments provided in this application can be combined with each other without contradiction.

[0053] In flexible DC transmission systems, DC circuit breakers serve as critical anomaly isolation devices, and their breaking performance directly impacts the system's safety and stability. When a short circuit occurs, the DC circuit breaker plays a vital role in rapidly disconnecting the circuit and isolating the anomaly. However, during the current interruption process, the vacuum switch is subjected to significant electrical stress. Issues such as prolonged arcing time, insufficient zero-voltage recovery time, and high pre-zero current drop rate affect the vacuum switch's insulation recovery capability after the current crosses zero, severely impacting its performance.

[0054] To address the aforementioned issues, this disclosure provides a circuit breaker and its insulation recovery circuit. The insulation recovery circuit uses a control module to detect the current interruption status of the circuit breaker. When the circuit breaker experiences current interruption, the control module controls the vacuum switch to open and the current guiding module to close. When the vacuum switch is open, current still exists due to the arcing phenomenon. At this time, the first commutation trigger unit and the second commutation trigger unit generate a voltage difference across the closed current guiding module, thereby guiding the abnormal current flowing through the vacuum switch to the current guiding module. As a result, the abnormal current flowing through the vacuum switch is reduced, which in turn reduces the arcing duration of the vacuum switch and prolongs the zero-voltage recovery time, thereby improving the insulation recovery speed of the vacuum switch and enhancing its insulation recovery capability.

[0055] This disclosure provides an insulation restoration circuit for a circuit breaker, which includes a control module, a current guiding module, and a commutation triggering module.

[0056] The control module is connected to the control terminal of the vacuum switch.

[0057] The current guiding module and the vacuum switch are located in different branches, and the control terminal of the current guiding module is connected to the control module.

[0058] The commutation triggering module includes a first commutation triggering unit and / or a second commutation triggering unit; the first commutation triggering unit is connected in series with the current guiding module, the control terminal of the second commutation triggering unit is connected to the control module, and the second commutation triggering unit is connected in series with the vacuum switch.

[0059] The control module is used to control the vacuum switch to open and the current guiding module to close when the circuit breaker interrupts current. The first commutation trigger unit and the second commutation trigger unit are both used to change the voltage difference across the current guiding module so as to guide the abnormal current flowing through the vacuum switch to the current guiding module. The control module is also used to control the current guiding module to cross zero so as to open the current guiding module and control the vacuum switch to close under zero voltage.

[0060] For example, Figure 1 This is a schematic diagram of the insulation restoration circuit of a circuit breaker provided in an embodiment of the present disclosure, as shown below. Figure 1 As shown, the insulation restoration circuit includes: a control module 100, a current guiding module 200, a first commutation trigger unit 310, and a second commutation trigger unit 320. The control module 100 is connected to the control terminals of the vacuum switch 400, the current guiding module 200, and the second commutation trigger unit 320. The current guiding module 200 and the first commutation trigger unit 310 are connected in series in the first branch, and the vacuum switch 400 and the second commutation trigger unit 320 are connected in series in the second branch. The first branch and the second branch are connected in parallel. When the control module 100 detects a current interruption in the circuit breaker, it controls the vacuum switch 400 to open and the current guiding module 200 to close. When the vacuum switch 400 is open, current still exists due to arcing. At this time, the first commutation trigger unit 310 and the second commutation trigger unit 320, through their own voltage difference changes, cause a voltage difference to be generated across the closed current guiding module 200. Because the first commutation trigger unit 310 and the second commutation trigger unit 320 generate a voltage difference across the current guiding module 200, the abnormal current flowing through the vacuum switch 400 is guided to the current guiding module 200. Furthermore, since both the first commutation trigger unit 310 and the second commutation trigger unit 320 can generate a voltage difference across the current guiding module 200, even if either the first commutation trigger unit 310 or the second commutation trigger unit 320 experiences a short-circuit fault, the other can still generate a voltage difference across the current guiding module 200, thereby guiding the abnormal current flowing through the vacuum switch 400 to the current guiding module 200. Therefore, the embodiments of this disclosure can increase the stability of the entire insulation restoration circuit.

[0061] As yet another example, Figure 2 A schematic diagram of the insulation restoration circuit of another circuit breaker provided in this disclosure embodiment is shown below. Figure 2As shown, the insulation restoration circuit includes a control module 100, a current guiding module 200, and a first commutation triggering unit 310. The control module 100 is connected to the control terminals of the vacuum switch 400 and the current guiding module 200. The current guiding module 200 and the first commutation triggering unit 310 are connected in series in the first branch, and the vacuum switch 400 is connected in parallel with the first branch. When the control module 100 detects that the circuit breaker has interrupted current, it controls the vacuum switch 400 to open and the current guiding module 200 to close. When the vacuum switch 400 is open, current still exists due to arcing. At this time, the first commutation triggering unit 310 generates a voltage difference across the closed current guiding module 200, thereby guiding the abnormal current flowing through the vacuum switch 400 to the current guiding module 200.

[0062] As yet another example, Figure 3 A schematic diagram of the insulation restoration circuit of another circuit breaker provided in this disclosure embodiment is shown below. Figure 3 As shown, the insulation restoration circuit includes a control module 100, a current guiding module 2000, and a second commutation triggering unit 320. The control module 100 is connected to the control terminals of the vacuum switch 400, the current guiding module 200, and the second commutation triggering unit 320. The vacuum switch 400 and the second commutation triggering unit 320 are connected in series in the second branch, and the current guiding module 200 is connected in parallel with the second branch. When the control module 100 detects a current interruption in the circuit breaker, it controls the vacuum switch 400 to open and the current guiding module 200 to close. Even when the vacuum switch 400 is open, current still exists due to arcing. At this time, the second commutation triggering unit 320 creates a voltage difference across the closed current guiding module 200, thereby guiding the abnormal current flowing through the vacuum switch 400 to the current guiding module 200.

[0063] The abnormal current flowing through the vacuum switch 400 has the same current direction as the abnormal current flowing through the current guiding module 200. At this time, the abnormal current flowing through the vacuum switch 400 is reduced because it is diverted to the current guiding module 200. Therefore, the time for the abnormal current in the vacuum switch 400 to decrease from its maximum value to zero is reduced, thereby reducing the arcing duration of the vacuum switch 400. The earlier end of the arcing phenomenon in the vacuum switch 400 prolongs the time for the voltage to recover from zero voltage, i.e., the zero-voltage recovery time is extended. Therefore, this disclosure can improve the insulation recovery speed of the vacuum switch 400, thus enhancing its insulation recovery capability. Meanwhile, the control module 100 also uses techniques such as current injection, load reversing switch commutation, and coupling negative voltage commutation to achieve zero current crossing of the current in the current guiding module 200. After the current crosses zero, the current guiding module 200 is naturally turned off until there is no current in the entire circuit. When the vacuum switch 400 is in a zero-voltage state, the control module controls the vacuum switch 400 to turn on again, thereby realizing the insulation restoration of the entire circuit breaker. Furthermore, the vacuum switch 400 completes the insulation restoration in a zero-voltage state, which can effectively reduce the risk of secondary breakdown.

[0064] In some embodiments, Figure 4 This disclosure provides a schematic diagram of the structure of a current guiding module, as shown in the embodiment below. Figure 4 As shown, the current guiding module 200 includes multiple vacuum trigger switches 210.

[0065] Multiple vacuum trigger switches 210 are connected in series, and the control terminals of the multiple vacuum trigger switches 210 are all connected to the control module 100; the vacuum trigger switches 210 are used to turn on when they receive a turn-on signal sent by the control module 100.

[0066] For example, when the control module 100 detects a current interruption in the circuit breaker, it sends a conduction signal to multiple vacuum trigger switches 210, causing all vacuum trigger switches 210 to conduct. Furthermore, a voltage difference is generated across the multiple vacuum trigger switches 210 via a commutation trigger module, thereby guiding the abnormal current flowing through the vacuum switches to the multiple vacuum trigger switches 210. Additionally, there is a series gap between each vacuum trigger switch 210. The total series gap of the multiple vacuum trigger switches 210 is much larger than the total series tripping distance of the vacuum switches during current interruption. Therefore, the withstand voltage capability of the multiple vacuum trigger switches 210 is higher than that of the vacuum switches, enabling them to withstand greater overvoltage after a current interruption in the circuit breaker, thus protecting the vacuum switches.

[0067] In some embodiments, Figure 5 A schematic diagram of the insulation restoration circuit of another circuit breaker provided in this disclosure embodiment is shown below. Figure 5As shown, the first commutation trigger unit includes an energy storage device 211 and a pre-charging circuit 212.

[0068] The energy storage device 211 is connected in series with the current guiding module 200. The pre-charging circuit 212 is used to charge the energy storage device 211. The pre-charging circuit 212 stops charging in response to the charging stop signal sent by the control module 100. The energy storage device 211 is used to change the voltage difference across the current guiding module 200 when the current guiding module 200 is turned on.

[0069] For example, the energy storage device 211 and the current guiding module 200 are connected in series in the first branch, and the first branch is connected in parallel with the vacuum switch 400. The control module 100 is connected to the pre-charging circuit 212. During normal operation of the circuit breaker, the pre-charging circuit 212 charges the energy storage device 211, allowing it to store charge. When the control module 100 detects a current interruption in the circuit breaker, it controls the vacuum switch 400 to open and the current guiding module 200 to close. The pre-charging circuit 212 stops charging the energy storage device. When the vacuum switch 400 is open, current still exists due to arcing. Therefore, the energy storage device 211 can release charge through the vacuum switch 400 and the current guiding module 200, creating a voltage difference across the current guiding module 200. This causes the current flow in the current guiding module 200 to be the same as the current flow in the vacuum switch 400, thereby guiding the abnormal current flowing through the vacuum switch 400 to the current guiding module 200. At this time, the abnormal current flowing through the vacuum switch 400 is reduced because it is diverted to the current guiding module 200. Therefore, the time for the abnormal current in the vacuum switch 400 to decrease from its maximum value to zero is reduced, thereby reducing the arcing duration of the vacuum switch 400. The earlier end of the arcing phenomenon in the vacuum switch 400 extends the time for the vacuum switch 400 to recover voltage from zero voltage, that is, the zero voltage recovery time is extended. Therefore, this disclosure can improve the insulation recovery speed of the vacuum switch 400 and enhance the insulation recovery capability of the vacuum switch 400.

[0070] In some embodiments, the energy storage device includes a first capacitor; the first capacitor is connected in series with a current guiding module, and a pre-charging circuit is used to charge the first capacitor.

[0071] For example, during normal operation of the circuit breaker, the pre-charging circuit charges the first capacitor, allowing it to store charge. When the control module detects a current interruption in the circuit breaker, it controls the vacuum switch to open and the current guiding module to turn on. The pre-charging circuit stops charging the first capacitor. Because current still exists due to arcing when the vacuum switch is open, the first capacitor can release its charge through the vacuum switch and the current guiding module, creating a voltage difference across the current guiding module. This allows any abnormal current flowing through the vacuum switch to be guided to the current guiding module. Furthermore, due to the capacitor's freewheeling characteristic, the rate of current decrease in the circuit is reduced, thereby reducing the zero-precession current rate of the vacuum switch. This prevents an excessively high zero-precession current rate from affecting the insulation recovery speed of the vacuum switch, thus enhancing its insulation recovery capability.

[0072] In some embodiments, the second commutation trigger unit includes a first switch and / or a second switch;

[0073] The control terminals of the first switch and the second switch are both connected to the control module. The first switch is connected in series with the vacuum switch, or the second switch is connected in series with the vacuum switch, or both the first switch and the second switch are connected in series with the vacuum switch. The first switch and the second switch are both used to disconnect when the control module determines that the circuit breaker has interrupted current. One of the first switch and the second switch includes a power electronic switch and the other includes a high-arc voltage mechanical switch.

[0074] For example, the first switch is a power electronic switch and the second switch is a high-arc voltage mechanical switch, or the first switch is a high-arc voltage mechanical switch and the second switch is a power electronic switch. The second commutation trigger unit may include only the first switch, only the second switch, or the first and second switches connected in series. When the second commutation trigger unit includes only the first switch or only the second switch, when the control module detects that the circuit breaker has interrupted current, it controls the vacuum switch to open and the current guiding module to turn on. At this time, the first switch or the second switch is also controlled to open by the control module. For example, the first switch is a power electronic switch and the second switch is a high-arc voltage mechanical switch. When the first switch is open, the first switch will generate a voltage value due to the arcing phenomenon, thereby creating a voltage difference across the current guiding module. Since the power electronic switch contains a metal oxide varistor (MOV), when the second switch is open, current will flow through the MOV. When a large current flows through the MOV, it will limit the voltage across the second switch to a threshold range, achieving a capacitor-like effect, thereby creating a voltage difference across the current guiding module.

[0075] When the second commutation trigger unit includes both a first switch and a second switch, when the control module detects a current interruption in the circuit breaker, it controls the vacuum switch to open and the current guiding module to turn on. At this time, the first and second switches are opened by the control module, and a voltage difference is generated across the current guiding module. Since the first and second switches are connected in series, if one of the first and second switches experiences a fault such as a short circuit, the other can still function normally, generating a voltage difference across the current guiding module, thus enhancing the stability of the entire insulation recovery circuit.

[0076] In some embodiments, the first switch includes a power electronic switch, and the second switch includes a high-arc-voltage mechanical switch.

[0077] The control terminal of the power electronic switch is connected to the control module, and the power electronic switch is connected in series with the vacuum switch.

[0078] The control terminal of the high-arc voltage mechanical switch is connected to the control module, and the high-arc voltage mechanical switch is connected in series with the vacuum switch.

[0079] For example, Figure 6 A schematic diagram of the insulation restoration circuit of another circuit breaker provided in this disclosure embodiment is shown below. Figure 6 As shown, the first switch includes a power electronic switch 321. The control module 100 is connected to the control terminal of the vacuum switch 400, the control terminal of the current guiding module 200, and the control terminal of the power electronic switch 321. The power electronic switch 321 and the vacuum switch 400 are connected in series in the second branch, and the second branch is connected to the current guiding module 200.

[0080] When the control module 100 detects a current interruption in the circuit breaker, it controls the vacuum switch 400 to open and the current guiding module 200 to close. Even when the vacuum switch 400 is open, current still exists due to arcing. Upon receiving the open signal from the control module 100, the power electronic switch 321 opens, and current flows through the MOV of the power electronic switch 321. Under high current conditions, the MOV limits the voltage across the power electronic switch 321 to a threshold range, thus creating a voltage difference across the current guiding module 200. This guides the abnormal current flowing through the vacuum switch 400 to the current guiding module 200. Furthermore, the control module 100 can control the conduction amplitude of the power electronic switch 321, thereby controlling the current flowing through it and reducing the zero-precession current drop rate of the vacuum switch 400. This prevents an excessively high zero-precession current drop rate from affecting the insulation recovery speed of the vacuum switch 400.

[0081] Figure 7 A schematic diagram of the insulation restoration circuit of another circuit breaker provided in this disclosure embodiment is shown below. Figure 7As shown, the second switch includes a high-arc voltage mechanical switch 322. The control module 100 is connected to the control terminal of the vacuum switch 400, the control terminal of the current guiding module 200, and the control terminal of the high-arc voltage mechanical switch 322. The high-arc voltage mechanical switch 322 and the vacuum switch 400 are connected in series in the second branch, and the second branch is connected to the current guiding module 200.

[0082] When the control module 100 detects that the circuit breaker has interrupted the current, it controls the vacuum switch 400 to open and the current guiding module 200 to close. When the vacuum switch 400 is opened, there is still current due to the arcing phenomenon. At this time, the high arc voltage mechanical switch 322 also receives the disconnection signal from the control module 100 and opens, thereby generating an arcing phenomenon. This causes a voltage difference to be generated across the current guiding module 200, thereby guiding the abnormal current flowing through the vacuum switch 400 to the current guiding module 200.

[0083] The abnormal current flowing through the vacuum switch is reduced because it is diverted to the current guiding module. Therefore, the time for the abnormal current in the vacuum switch to decrease from its maximum value to zero is shortened, resulting in a shorter arcing duration. The earlier end of the arcing phenomenon in the vacuum switch prolongs the time for voltage recovery from zero voltage, i.e., the zero-voltage recovery time is extended. Therefore, this disclosure can improve the insulation recovery speed of the vacuum switch and enhance its insulation recovery capability. Simultaneously, the control module also uses techniques such as current injection, load reversing switch commutation, and coupling negative voltage commutation to achieve zero-current crossing of the current in the current guiding module. After the current crosses zero, the current guiding module naturally turns off until there is no current in the entire circuit. Then, the control module controls the vacuum switch to turn on again, thereby achieving insulation recovery of the entire circuit breaker.

[0084] In some embodiments, the unidirectional topology of the power electronic switch includes any one of an insulated gate bipolar transistor, an integrated gate commutated thyristor, and a gate injection enhancement transistor.

[0085] Specifically, the power electronic switch can be a unidirectional topology structure, which allows the current in the insulation restoration circuit to flow in only one direction. The power electronic switch can be any one of the following: Insulated-Gate Bipolar Transistor (IGBT), Integrated Gate-Commutated Thyristor (IGCT), and Injection Enhanced Gate Transistor (IEGT).

[0086] In some embodiments, the bidirectional topology of the power electronic switch includes any one of an anti-series structure, a full-bridge structure, and a diode bridge structure.

[0087] For example, Figure 8 This is a schematic diagram of an anti-series structure of a power electronic switch provided in an embodiment of this disclosure. Figure 9 This is a schematic diagram of a full-bridge structure of a power electronic switch provided in an embodiment of this disclosure. Figure 10 This is a schematic diagram of a diode bridge structure for a power electronic switch provided in an embodiment of the present disclosure. The bidirectional topology of the power electronic switch can be any one of an anti-series structure, a full-bridge structure, and a diode bridge structure, so that the insulation recovery circuit can achieve bidirectional commutation without using an energy storage device as a commutation trigger module.

[0088] In some embodiments, Figure 11 This is a schematic diagram illustrating the current changes within a vacuum switch and current guiding module, as provided in an embodiment of this disclosure. Figure 11 As shown, at the first moment t1, the control module controls the vacuum switch to open and the current guiding module to turn on; the commutation trigger module is used to change the voltage difference across the current guiding module so as to guide the abnormal current flowing through the vacuum switch to the current guiding module between the first moment t1 and the second moment t2; where the first moment t1 is the moment when the circuit breaker interrupts the current.

[0089] At the second moment t2, the vacuum switch is in a zero-current state, and all the abnormal current flowing through the vacuum switch is guided to the current guiding module.

[0090] At the third moment t3, the current guiding module controls the current guiding module to cause the current to cross zero so that the current guiding module is disconnected, and after the third moment, it controls the vacuum switch to conduct under zero voltage.

[0091] For example, during the first moment t1, the circuit breaker operates normally, the operating current flows through the vacuum switch, and there is no current in the current guiding module.

[0092] At the first moment t1, the control module detects that the circuit breaker has interrupted the current. The control module controls the vacuum switch to open and the current guiding module to turn on. At this time, the commutation trigger module changes the voltage difference across the current guiding module, so that part of the current flowing through the vacuum switch begins to be guided to the current guiding module.

[0093] Between the first time t1 and the second time t2, part of the abnormal current flowing through the vacuum switch is guided to the current guiding module. The current in the vacuum switch gradually decreases, and the current in the current guiding module gradually increases until the second time t2, when the commutation operation from the vacuum switch to the current guiding module is completed. The vacuum switch is in a zero-current state. In the subsequent time, there is no current in the vacuum switch, and all abnormal currents flow through the current guiding module.

[0094] Between the second time t2 and the third time t3, there is no current in the vacuum switch, and all abnormal currents flow through the current guiding module. During this period, the control module uses techniques such as current injection, load reversing switch commutation, and coupling negative voltage commutation to enable the current guiding module to complete the current zero crossing at the third time t3 and turn off the current guiding module. After the third time t3, the current in the current guiding module gradually decreases.

[0095] When the current in the current guiding module drops to zero after the third time t3, the control module controls the vacuum switch to turn on again, thereby realizing the insulation restoration of the entire circuit breaker. Moreover, the vacuum switch completes the insulation restoration in a zero-voltage state, which can effectively reduce the risk of secondary breakdown.

[0096] This disclosure guides the abnormal current flowing through the vacuum switch to the current guiding module, thereby reducing the abnormal current flowing through the vacuum switch between the first time t1 and the second time t2 due to the diversion to the current guiding module. As a result, the time for the abnormal current in the vacuum switch to decrease from its maximum value to zero is reduced, which in turn reduces the arcing duration of the vacuum switch (i.e., the time between the first time t1 and the second time t2). The earlier end of the arcing phenomenon in the vacuum switch prolongs the time for the vacuum switch to recover voltage from zero voltage (i.e., the time after the second time t2), that is, prolongs the zero voltage recovery time. Therefore, this disclosure can improve the insulation recovery speed of the vacuum switch and enhance its insulation recovery capability.

[0097] This disclosure also provides a circuit breaker, which includes the insulation restoration circuit and vacuum switch provided in any of the above embodiments.

[0098] It is understood that the circuit breaker provided in this application embodiment can achieve the corresponding beneficial effects of the insulation restoration circuit provided in the above embodiments, which will not be elaborated here.

[0099] The above are merely specific embodiments of this disclosure, enabling those skilled in the art to understand or implement this disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to these embodiments, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An insulation restoration circuit for a circuit breaker, characterized in that, include: The control module is connected to the control terminal of the vacuum switch; The current guiding module is located in a different branch from the vacuum switch, and the control terminal of the current guiding module is connected to the control module. The commutation triggering module includes a first commutation triggering unit and / or a second commutation triggering unit; the first commutation triggering unit is connected in series with the current guiding module, the control terminal of the second commutation triggering unit is connected to the control module, and the second commutation triggering unit is connected in series with the vacuum switch; The control module is used to control the vacuum switch to open and the current guiding module to turn on when the circuit breaker interrupts the current. The first commutation trigger unit and the second commutation trigger unit are both used to change the voltage difference across the current guiding module so as to guide the abnormal current flowing through the vacuum switch to the current guiding module. The control module is also used to control the current guiding module to cross zero so that the current guiding module is disconnected, and to control the vacuum switch to conduct when there is no current.

2. The insulation restoration circuit according to claim 1, characterized in that, The current guiding module includes multiple vacuum trigger switches; The multiple vacuum trigger switches are connected in series, and the control terminals of the multiple vacuum trigger switches are all connected to the control module; The vacuum trigger switch is used to turn on when it receives a turn-on signal sent by the control module.

3. The insulation restoration circuit according to claim 2, characterized in that, The first commutation triggering unit includes an energy storage device and a pre-charging circuit; The energy storage device is connected in series with the current guiding module. The pre-charging circuit is used to charge the energy storage device. The pre-charging circuit stops charging in response to a charging stop signal sent by the control module. The energy storage device is used to change the voltage difference across the current guiding module when the current guiding module is turned on.

4. The insulation restoration circuit according to claim 3, characterized in that, The energy storage device includes a first capacitor; the first capacitor is connected in series with the current guiding module, and the pre-charging circuit is used to charge the first capacitor.

5. The insulation restoration circuit according to claim 2, characterized in that, The second commutation triggering unit includes a first switch and / or a second switch; The control terminals of both the first switch and the second switch are connected to the control module. The first switch is connected in series with the vacuum switch. or, The second switch is connected in series with the vacuum switch. or, Both the first switch and the second switch are connected in series with the vacuum switch; Both the first switch and the second switch are used to disconnect the circuit breaker when the control module determines that a current interruption has occurred; one of the first switch and the second switch includes a power electronic switch and the other includes a high-arc voltage mechanical switch.

6. The insulation restoration circuit according to claim 5, characterized in that, The first switch includes a power electronic switch; the second switch includes a high-arc voltage mechanical switch. The control terminal of the power electronic switch is connected to the control module, and the power electronic switch is connected in series with the vacuum switch; The control terminal of the high-arc voltage mechanical switch is connected to the control module, and the high-arc voltage mechanical switch is connected in series with the vacuum switch.

7. The insulation restoration circuit according to claim 6, characterized in that, The unidirectional topology of the power electronic switch includes any one of an insulated gate bipolar transistor, an integrated gate commutated thyristor, and a gate injection enhancement transistor.

8. The insulation restoration circuit according to claim 6, characterized in that, The bidirectional topology of the power electronic switch includes any one of the following: anti-series structure, full-bridge structure, and diode bridge structure.

9. The insulation restoration circuit according to claim 1, characterized in that, At the first moment, the control module controls the vacuum switch to open and the current guiding module to turn on; the commutation trigger module is used to change the voltage difference across the current guiding module so as to guide the abnormal current flowing through the vacuum switch to the current guiding module between the first moment and the second moment; wherein, the first moment is the moment when the circuit breaker interrupts the current. At the second moment, the vacuum switch is in a zero-current state, and the abnormal current flowing through the vacuum switch is completely guided to the current guiding module; At the third moment, the current guiding module controls the current guiding module to cross zero to disconnect the current guiding module, and after the third moment, controls the vacuum switch to conduct under zero voltage.

10. A circuit breaker, characterized in that it includes an insulation restoration circuit as described in any one of claims 1-9 and a vacuum switch.

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