System and method for bypassing a faulty submodule in an electrical circuit breaker.
The bypass element with a parallel switch and actuator provides a stable short-circuit path to bypass faulty circuit breaker modules, ensuring uninterrupted current flow and minimizing damage in modular high-voltage circuit breakers.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- SCIBREAK
- Filing Date
- 2024-06-27
- Publication Date
- 2026-07-29
AI Technical Summary
Existing modular high-voltage circuit breakers face failure scenarios where a faulty circuit breaker module fails to properly turn on, potentially leading to damage and obstructing current flow, which existing solutions do not adequately address.
A bypass element is connected in parallel with the circuit breaker module, providing an alternative current path through a switch, such as a mechanical switch, to ensure current flow is not obstructed, using actuators like solenoids or pyrotechnical actuators to establish a stable short-circuit.
Ensures uninterrupted current flow by bypassing faulty modules, minimizing the risk of damage and maintaining system operation, even if one or more modules fail, by creating a stable short-circuit path.
Smart Images
Figure 2026525248000001_ABST
Abstract
Description
Technical Field
[0003]
[0001] The present invention relates to an electrical circuit breaker. In particular, the present invention relates to a circuit breaker that uses a resonant circuit to achieve an artificial zero-crossing of the current passing through a mechanical circuit breaker, thereby enabling current interruption without a zero-crossing of the primary current to be interrupted.
Background Art
[0002] Circuit breakers for interrupting current when there is no zero-crossing (such as in the case of direct current) can be designed by using a resonant circuit to flow a resonant current in a mechanical circuit breaker such as a vacuum circuit breaker through which the line current passes. See FIGS. 1 and 2. Opening a mechanical circuit breaker alone generally does not remove the current. Instead, an arc is formed inside the mechanical circuit breaker, thereby allowing the current to continue to flow. However, when the resonant current exceeds the line current, a zero-crossing occurs, thereby interrupting the current passing through the mechanical switch. The current is then rectified by an energy absorption device such as a metal oxide arrester. This device provides a counter voltage that drives the line current to zero when it begins to conduct, thereby completing the current arc extinction process.
[0003] One type of such active resonant circuit breaker uses a power electronic voltage source converter to excite the resonant circuit; see Figure 3, and refer to European Patent Publication No. 3398198 and European Patent Publication No. 3161846. This type offers several advantages. High resonant frequencies can be used, which means that the components in the resonant circuit are smaller. Furthermore, the resonant process can be precisely controlled by the voltage source converter. A typical procedure for interrupting current using such a circuit breaker is as follows: First, a line current I flows through a mechanical circuit breaker 1. To initiate the interruption process, the circuit breaker is opened, preferably using a fast actuator. The current continues to flow through the arc inside the breaker. Next, an AC voltage Uo is generated by the voltage source converter 4 at the resonant frequency of the resonant circuit 3. This results in a resonant current Io flowing through the resonant circuit with increasing amplitude. In particular, the resonant current also flows through the mechanical circuit breaker. When the amplitude eventually exceeds the magnitude of the line current I, a zero crossing occurs in the current Isw flowing through the mechanical circuit breaker. This extinguishes the arc and stops the flow of Isw. Since there is no other path for the line current I to flow, the line current I is forced into surge arrester 2. Surge arresters are generally selected to provide a counter voltage significantly higher than the drive voltage in the grid when current is flowing. This forces the line current to zero and completes the current interruption process.
[0004] Figure 4 shows a different embodiment from the circuit breaker described above, in which a voltage source is used to excite the resonant circuit. In this case, the arrangement of the surge arrester is modified to be connected in series with the inductor of the resonant circuit. Figure 4 also shows how several sets of voltage source converters and resonant circuits can be connected in parallel to achieve a higher resonant current.
[0005] It is also known that a high-voltage circuit breaker can be designed by connecting several circuit breaker modules 10 of the described types, which are designed for low voltage, in series; see Figure 5. This has the important advantage that current interruption is still possible even if one of the circuit breaker modules is unable to properly interrupt the current, as long as the combined voltage provided by the other modules is sufficient to bring the line current to zero.
[0006] The type of circuit breaker described above does not provide contact isolation when open because the energy absorption device 2 is connected in parallel with the mechanical circuit breaker 1. This means that a low current may flow even when the circuit breaker is open. Therefore, it is common practice to connect a switch in the form of a residual current circuit breaker 5 in series with the main circuit breaker. The residual current circuit breaker is used in this case to remove the current flowing through the energy absorption device and provide galvanic isolation to the path of the main current. Residual current circuit breakers generally only require very limited current interruption capability.
[0007] Using the residual current circuit breaker described above to close a current circuit is often beneficial. By this method of closing the circuit, the circuit breaker module 10 is normally in a closed state, or, if the circuit breaker consists of several circuit breaker modules connected in series, all of them are closed and thus conduct. The voltage is then maintained by the residual current circuit breaker, which is in the off state. When a command to close the current circuit is given, the residual current circuit breaker closes, and a path for current is formed. Therefore, the residual current circuit breaker requires current-carrying capability (i.e., turn-on capability).
[0008] A possible failure scenario when using such a modular high-voltage circuit breaker occurs when one or more of the circuit breaker modules 10 fail to properly turn on. If the modular high-voltage circuit breaker is commanded to turn on, and one or more of the modules fail to start energizing as intended while in the ON state, this or these modules may still be forced to conduct current, potentially resulting in their destruction. Therefore, it is desirable to minimize the probability of this failure scenario occurring. [Prior art documents] [Patent Documents]
[0009] [Patent Document 1] European Patent Publication No. 3398198 [Patent Document 2] European Patent Publication No. 3161846 [Overview of the project] [Problems that the invention aims to solve]
[0010] Therefore, an object of the present invention is to provide an apparatus and method for interrupting current in which a faulty circuit breaker module does not interfere with the operation of the apparatus. Another object is to provide an apparatus and method for interrupting current in which the risk of damage to the faulty circuit breaker module is minimized. [Means for solving the problem]
[0011] The present invention is based on the insight that individual circuit breaker modules can be short-circuited, and thus the flow of current is not obstructed. This is achieved by providing an alternative path for the current through the circuit breaker submodules by a bypass element connected in parallel with the circuit breaker module.
[0012] According to a first aspect of the present invention, there is a device for interrupting current having a first terminal and a second terminal configured to electrically connect two sections of a power system, the device comprising a circuit breaker module configured to interrupt current, the circuit breaker module being provided between the first terminal and the second terminal and forming a first current path between the first terminal and the second terminal, the device comprising a bypass device connected in parallel with the first current path and thereby forming a second current path between the first terminal and the second terminal, the bypass device comprising a switch, preferably a mechanical switch.
[0013] In a preferred embodiment, the bypass device comprises a first contact and a second contact, the first contact being movable, and a stable short circuit can be formed by joining the first contact and the second contact.
[0014] In a preferred embodiment, the first contact and the second contact form part of a vacuum circuit breaker.
[0015] In a preferred embodiment, the first contact is displaceable to contact the second contact by an electromechanical actuator, preferably a solenoid or a Thomson coil.
[0016] In a preferred embodiment, the first contact is displaceable by a pyroelectric actuator to contact the second contact.
[0017] In a preferred embodiment, a thrust actuator is provided that is configured to directly press the first contact point to bring it into contact with the second contact point.
[0018] In a preferred embodiment, a bistable mechanism is provided that is configured to maintain sufficient contact pressure within the bypass device after the switch is closed.
[0019] In a preferred embodiment, a pin pusher, preferably a pyrotechnical pin pusher, for operating the switch is provided.
[0020] In a preferred embodiment, a spring load mechanism having a spring is provided, configured to move a first contact into contact with a second contact, whereby the spring maintains the necessary contact pressure between the first contact and the second contact in the closed position, and an actuator is configured to release the spring load mechanism.
[0021] In a preferred embodiment, the circuit breaker module comprises a mechanical circuit breaker that normally conducts current between a first terminal and a second terminal, and a resonant circuit configured to be excited to achieve a zero crossing of the current passing through the mechanical circuit breaker. Preferably, a voltage source converter is provided to excite the resonant circuit to achieve a zero crossing of the current passing through the mechanical circuit breaker.
[0022] According to a second aspect of the present invention, there is provided a system for interrupting a current, comprising at least two devices for interrupting a current according to the present invention, wherein the at least two devices for interrupting a current are connected in series.
[0023] According to a third aspect of the present invention, there is provided a method of operating a system for interrupting a current according to the present invention, the method comprising the steps of identifying that a circuit breaker module is faulty, and then operating an associated bypass device.
[0024] Here, the present invention will be described by way of example with reference to the accompanying drawings.
Brief Description of the Drawings
[0025] [Figure 1] FIG. shows a device for interrupting a prior art current. [Figure 2] FIG. shows a device for interrupting a prior art current. [Figure 3]This diagram shows a device for interrupting electric current using prior art. [Figure 4] This diagram shows a device for interrupting electric current using prior art. [Figure 5] This diagram shows a device for interrupting electric current using prior art. [Figure 6] This figure shows a general embodiment of a device for interrupting electric current according to the present invention. [Figure 7] This figure shows a general embodiment of a device for interrupting electric current according to the present invention. [Figure 8] This figure shows an embodiment for implementing the bypass element according to the present invention. [Figure 9] This figure shows an embodiment for implementing the bypass element according to the present invention. [Modes for carrying out the invention]
[0026] Next, a device for interrupting current according to the present invention will be described with particular reference to Figures 6 and 7.
[0027] The present invention ensures that a faulty circuit breaker module is in a short-circuit state and therefore does not obstruct the flow of current. This is achieved by providing an alternative path for the current through the circuit breaker module by a bypass element connected in parallel with the circuit breaker module. Thus, one embodiment of a device for interrupting current according to the present invention comprises a first terminal 11 and a second terminal 12 configured to electrically connect two sections 100, 200 of a power system. A circuit breaker module 10 configured to interrupt current is provided between the first terminal 11 and the second terminal 12, forming a first current path between the first terminal 11 and the second terminal 12. A bypass device 50 is connected in parallel with the first current path, thereby forming a second current path between the first terminal 11 and the second terminal 12, the bypass device 50 comprising a switch. Thereafter, this bypass element is turned on by command and configured to allow line current to pass indefinitely, or at least until the next maintenance event in which the faulty circuit breaker module 10 can be replaced or repaired. In a preferred embodiment, the bypass device 50 does not require the ability to return to a non-conductive state, and is optionally provided without such ability.
[0028] The bypass device 50 is preferably provided as a mechanical switch comprising at least one fixed contact 53 and one movable contact 52, usually separated by a sufficiently large distance, so as to be able to interrupt the voltage present across the circuit breaker module 10 when it is open. The bypass device 50 is actuated by forcing the movable contact into contact with the fixed contact.
[0029] Such a bypass device 50 can be implemented in different ways. In one embodiment, the same type of mechanical circuit breaker and associated actuator are used to interrupt the current in the circuit breaker module 10. However, this can be an unnecessarily expensive solution, especially since the bypass element does not require the ability to interrupt the circuit, or even the ability to return to a non-conducting state.
[0030] One embodiment of the mechanical switch described above used in the bypass element is the use of a vacuum circuit breaker. This allows the contact separation in the normal state (open contact) to be short, preferably less than 20 millimeters, and more preferably less than 10 millimeters, thereby simplifying the actuator design as only a short actuator stroke is required. Furthermore, by using a vacuum circuit breaker, the integrity of the contact surfaces is also ensured because air or other gases that could cause oxidation of the contact surfaces are not present in the vacuum chamber.
[0031] Refer to Figure 8 for one embodiment of the actuator, which includes a pyrotechnical actuator 56. Such an actuator has the advantage of requiring only a relatively low-power electrical signal to operate and being able to apply a large force. Such a pyrotechnical actuator can be used to directly move the movable contact 52 of a bypass device so that a closed circuit is established. In such a case, it is also convenient that the bypass element also includes a bistable mechanism 57 to ensure that after closing the circuit, the movable contact 52 is pressed toward the fixed contact 53 with sufficient force to ensure that a stable electrical contact is established and maintained.
[0032] Alternatively, as shown in Figure 9, a pyrotechnical actuator, also known as a pyrotechnical pin puller 58, can be used to apply traction force and release the spring load mechanism 59 that forces the movable contact 52 toward the fixed contact 53 by pulling out the pin that initially holds the movable contact in the open position. The spring mechanism 59 can be designed to establish and maintain sufficient contact force after the closing operation to ensure that a stable electrical contact is established and maintained.
[0033] Furthermore, other forms of operating the movable contacts of a mechanical switch to the closed position are also possible. These include, but are not limited to, the use of electromagnetic actuators such as solenoids and Thomson coils. Importantly, the operating speed requirements for bypass elements are considerably lower than those for bypass elements for submodules in converters made from semiconductor modules.
[0034] The bypass device 50 can be operated by the entire circuit breaker control system, which is advantageous because the control system receives the measurement signals necessary to determine whether a fault has occurred in the main circuit breaker. It is also possible to have a separate controller for the bypass device 50. In this way, bypassing a faulty module does not depend on the correct functioning of the entire control system.
[0035] Refer to Figure 5, and similar to the prior art design described above, a circuit breaker for high voltages can be designed by connecting multiple N circuit breaker modules 10 designed for lower voltages in series; see Figure 7. This has the important advantage that current interruption is still possible even if one of the circuit breaker modules cannot properly interrupt the current, as long as the combined voltage provided by the other modules is sufficient to reduce the line current to zero.
[0036] When multiple circuit breaker modules 10 for interrupting current are connected in series, one or more of the bypass devices 50 can be activated, thereby bypassing each faulty circuit breaker module 10, as long as a functioning circuit breaker module 10 can receive the voltage across multiple N modules 10. Thus, in one embodiment, 16 circuit breaker modules 10 are connected in series, and each module 10 is designed to receive a voltage of 50 kilovolts. In such a system, it is sufficient if 14 circuit breaker modules 10 are functioning properly.
[0037] During the operation of the device for interrupting current, the various steps involving bypass are as follows: First, it is identified that the circuit breaker module 10 is faulty, i.e., unable to properly conduct current. Then, the associated bypass device 50 is activated, thereby forming a second current path that bypasses the circuit breaker module 10. Meanwhile, the other circuit breaker module 10 connected in series with the faulty circuit breaker module 10 conducts current between the first terminal 11 and the second terminal 12.
[0038] Preferred embodiments of devices, systems, and methods for interrupting electric current have been described. These can be modified within the scope of the appended claims without departing from the spirit of the invention. Thus, each circuit breaker module 10 is described as comprising one movable contact and one fixed contact. It will be understood that other configurations are possible as long as they have a contact arrangement configured to interrupt the current flowing between the contacts. Thus, it is possible to have two or more movable contacts and / or two or more fixed contacts. It is also possible to have only a movable contact.
Claims
1. A device (1) for interrupting current, comprising a first terminal (11) and a second terminal (12) configured to electrically connect two sections (100, 200) of a power system, wherein the device comprises a circuit breaker module (10) configured to interrupt current, In a device in which the circuit breaker module (10) is provided between the first terminal (11) and the second terminal (12), and a first current path is formed between the first terminal (11) and the second terminal (12), A bypass device (50) connected in parallel with the first current path, thereby forming a second current path between the first terminal (11) and the second terminal (12), wherein the bypass device (50) comprises a switch, preferably a mechanical switch. A device characterized by the following.
2. The apparatus according to claim 1, wherein the bypass device (50) comprises a first contact (52) and a second contact (53), and the first contact (52) is movable so as to be able to form a stable short circuit by connecting the first contact and the second contact to each other.
3. The apparatus according to claim 2,2, wherein the first contact (52) and the second contact (53) form part of a vacuum circuit breaker.
4. The apparatus according to claim 2 or 3, wherein the first contact (52) is displaceable to contact the second contact (53) by an electromechanical actuator, preferably a solenoid or a Thomson coil.
5. The apparatus according to claim 2 or 3, wherein the first contact (52) is displaceable by a pyroelectric actuator to contact the second contact (53).
6. The apparatus according to claims 4 and 5, further comprising a thrust actuator configured to directly press the first contact (52) to bring it into contact with the second contact (53).
7. The apparatus according to any one of claims 2 to 6, further comprising a bistable mechanism (57) configured to maintain sufficient contact pressure within the bypass device (50) after the switch is closed.
8. The apparatus according to any one of claims 2 to 5, comprising a pin puller 58, preferably a pyrotechnical pin puller, for operating the switch.
9. A spring load mechanism (59) having a spring configured to move the first contact to bring it into contact with the second contact, thereby maintaining the necessary contact pressure between the first contact and the second contact in the closed position, An actuator configured to release the aforementioned spring load mechanism and The apparatus according to claim 2 or 8, comprising:
10. The apparatus according to any one of claims 1 to 9, wherein the circuit breaker module (10) comprises a mechanical circuit breaker that normally conducts current between the first terminal (11) and the second terminal (12), and a resonant circuit configured to be excited to achieve a zero crossing of the current passing through the mechanical circuit breaker.
11. The apparatus according to claims 1 to 10, further comprising a voltage source converter configured to excite the resonant circuit to achieve zero-crossing of the current passing through the mechanical circuit breaker.
12. A system for interrupting current, comprising at least two devices for interrupting current as described in any of the preceding claims, wherein the at least two devices for interrupting current are connected in series.
13. A method for operating a system for interrupting current according to any one of claims 1 to 10, Steps include identifying that the circuit breaker module (10) is faulty, and then activating the associated bypass device (50). Methods that include...