Self-energy-taking direct-current circuit breaker
By designing a self-powered DC circuit breaker, the circuit breaker circuit is powered by an independent power supply line, and the voltage of the energy storage element is clamped. This solves the problem of high cost of high-voltage isolation devices and achieves high-voltage protection and cost reduction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TSINGHUA UNIVERSITY
- Filing Date
- 2026-04-17
- Publication Date
- 2026-05-15
AI Technical Summary
In ultra-high voltage applications, DC circuit breakers need to be equipped with costly high-voltage isolation devices for the power supply equipment, resulting in high manufacturing costs.
Design a self-powered DC circuit breaker. Under normal operating conditions, the energy storage element supplies power to the circuit breaker circuit through an independently set power supply line. Under energy extraction conditions, the circuit breaker circuit clamps the voltage across the energy storage element to avoid high voltage surges and overvoltages, thus achieving high voltage protection without the need for a high voltage isolation device.
It achieves high-voltage protection under the conditions of energy storage element power supply and charging, and reduces the manufacturing cost of DC circuit breakers.
Smart Images
Figure CN122052232A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of circuit breaker technology, and more particularly to a self-powered DC circuit breaker. Background Technology
[0002] With the development of DC transmission technologies such as flexible DC transmission, multi-terminal DC systems, and large-scale new energy access systems, the power system has put forward higher requirements for rapid DC fault clearing solutions, and DC circuit breakers have become the most ideal choice for DC fault isolation in DC transmission and distribution systems.
[0003] However, in ultra-high voltage applications, DC circuit breakers need to be equipped with costly high-voltage isolation devices for the power supply equipment, which makes DC circuit breakers expensive to manufacture. Summary of the Invention
[0004] To solve the above-mentioned technical problems, or at least partially solve them, this disclosure provides a self-powered DC circuit breaker that can achieve high-voltage isolation without the need for a costly high-voltage isolation device, thereby reducing the manufacturing cost of the DC circuit breaker.
[0005] This disclosure provides a self-powered DC circuit breaker, including: a circuit breaker circuit and an energy storage circuit.
[0006] The first terminal of the circuit breaker circuit is connected to the input terminal, and the second terminal of the circuit breaker circuit is connected to the output terminal. The energy storage circuit includes an energy storage element and a switching element; the first end of the energy storage element is connected to the third end of the circuit breaker circuit, the second end of the energy storage element is connected to the first end of the switching element, the second end of the switching element is connected to the second end of the circuit breaker circuit, and the energy storage element is also connected to the circuit breaker circuit through a power supply line. Under normal operating conditions of the circuit breaker circuit, the switching element is open, and the energy storage element supplies power to the circuit breaker circuit through the power supply line; When the circuit breaker circuit is in the energy extraction mode, the switching element is turned on, the circuit breaker circuit clamps the voltage across the energy storage element and charges the energy storage element.
[0007] Optionally, the circuit breaker circuit includes: a first switching device and a controllable voltage source; The first terminal of the first switching device is connected to the input terminal, the second terminal of the first switching device is connected to the first terminal of the controllable voltage source and the first terminal of the energy storage element, and the second terminal of the controllable voltage source is connected to the output terminal and the second terminal of the switching element. The first switching device and the controllable voltage source are both connected to the power supply line; When the switching element is off, the energy storage element is used to supply power to the first switching device and the controllable voltage source through the power supply line; When the switching element is turned on, the controllable voltage source operates in voltage clamping mode, clamping the voltage across the energy storage element.
[0008] Optionally, the controllable voltage source includes multiple power electronic devices; the multiple power electronic devices are connected in series and / or in parallel, and the control terminals of the multiple power electronic devices and the control terminals of the switching elements are all connected to the control module; The control module is used to control multiple power electronic devices to disconnect when the electrical energy of the energy storage element is less than or equal to a first electrical energy threshold, and to control a switching element to turn on when multiple power electronic devices are disconnected. The control module is also used to control the switching element to open when the electrical energy of the energy storage element is greater than the second electrical energy threshold, and to control multiple power electronic devices to turn on when the switching element is open. The first energy threshold is less than the second energy threshold.
[0009] Optionally, the self-powered DC circuit breaker may also include a second switching device; The first terminal of the second switching device is connected to the first terminal of the controllable voltage source, the second terminal of the second switching device is connected to the second terminal of the controllable voltage source, and the control terminal of the second switching device is connected to the control module. The control module is used to control the second switching device to open when the electrical energy of the energy storage element is less than or equal to the third electrical energy threshold, and to control the controllable voltage source to operate in voltage clamping mode when the second switching device is open. Among them, the conduction loss of the second switching device is less than that of the controllable voltage source.
[0010] Optionally, the second switching device includes a high-arc-voltage mechanical switch; The control module is used to control the high-arc voltage mechanical switch to open when the electrical energy of the energy storage element is less than or equal to the third electrical energy threshold, and to detect the switch break state of the high-arc voltage mechanical switch; when the switch break state of the high-arc voltage mechanical switch can withstand transient overvoltage, it controls the controllable voltage source to work in voltage clamping mode.
[0011] Optionally, high-arc-voltage mechanical switches include magnetic blow-out mechanical switches or multi-break mechanical switches.
[0012] Optionally, the switching element includes a thyristor or a trigger gap electrode.
[0013] Optionally, the circuit breaker circuit includes a resonant unit; The resonant unit includes a first inductor and a first capacitor; The first end of the first inductor is connected to the input terminal, the second end of the first inductor is connected to the first end of the first capacitor, and the second end of the first capacitor is connected to the output terminal.
[0014] Optionally, the circuit breaker circuit includes an energy-dissipating unit; The first end of the energy-consuming unit is connected to the input end, and the second end of the energy-consuming unit is connected to the output end.
[0015] Optionally, the energy storage element includes multiple energy storage devices; the multiple energy storage devices are connected in series and / or in parallel. Among them, energy storage devices include at least supercapacitors or batteries.
[0016] This disclosure provides a self-powered DC circuit breaker, comprising a circuit breaker circuit and an energy storage circuit. The first terminal of the circuit breaker circuit is connected to the input terminal, and the second terminal is connected to the output terminal. The energy storage circuit includes an energy storage element and a switching element. The first terminal of the energy storage element is connected to the third terminal of the circuit breaker circuit, and the second terminal of the energy storage element is connected to the first terminal of the switching element. The second terminal of the switching element is connected to the second terminal of the circuit breaker circuit. The energy storage element is also connected to the circuit breaker circuit via a power supply line. Under normal operating conditions of the circuit breaker circuit, the switching element is open, and the energy storage element supplies power to the circuit breaker circuit via the power supply line. Under energy-harvesting conditions of the circuit breaker circuit, the switching element is closed, the circuit breaker circuit clamps the voltage across the energy storage element, and charges the energy storage element. In the normal operating condition of the circuit breaker circuit, this disclosure provides power to the energy storage element through an independently provided power supply line. This avoids the high voltage in the high-voltage main circuit directly impacting the energy storage element, preventing it from being directly connected to the main circuit and thus achieving high-voltage protection during the energy storage element's power supply operation. Furthermore, during the energy extraction operation of the circuit breaker circuit, the circuit breaker circuit can clamp the voltage across the energy storage element. Therefore, even if the energy storage element is directly connected to the high-voltage main circuit, the circuit breaker circuit can clamp the voltage, preventing excessive voltage across the energy storage element during charging and achieving high-voltage protection during the charging operation. Thus, this disclosure achieves high-voltage protection during both the power supply and charging operations of the energy storage element. Therefore, high-voltage isolation can be achieved without the need for a high-voltage isolation device for the energy storage element, thereby reducing the manufacturing cost of the DC circuit breaker. Attached Figure Description
[0017] 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.
[0018] Figure 1 This is a schematic diagram of a self-powered DC circuit breaker provided in an embodiment of this disclosure.
[0019] Figure 2This is a schematic diagram of another self-powered DC circuit breaker provided in an embodiment of the present disclosure.
[0020] Figure 3 This is a schematic diagram of a controllable voltage source provided in an embodiment of the present disclosure.
[0021] Figure 4 This is a schematic diagram of another controllable voltage source provided in an embodiment of the present disclosure.
[0022] Figure 5 This is a schematic diagram of another controllable voltage source provided in an embodiment of this disclosure. Detailed Implementation
[0023] 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.
[0024] 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.
[0025] 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.
[0026] 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.
[0027] 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.
[0028] 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.
[0029] 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.
[0030] 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 implementation methods provided in the embodiments of this application can be combined with each other without contradiction.
[0031] With the development of DC transmission technologies such as flexible DC transmission, multi-terminal DC systems, and large-scale renewable energy integration systems, power systems have placed higher demands on rapid DC fault clearing solutions. DC circuit breakers have become the most ideal choice for DC fault isolation in DC transmission and distribution systems. Currently, among commonly used DC circuit breakers, hybrid DC circuit breakers are expensive in high-voltage applications, while mechanical DC circuit breakers suffer from reliability issues due to pre-charge capacitors. Oscillating DC circuit breakers, due to their advantages of low current loss, fast breaking speed, and good economy, have become a key focus of research and engineering applications in DC breaking equipment in recent years. However, in ultra-high voltage and extra-high voltage applications, oscillating DC circuit breakers require costly high-voltage isolation devices for the power supply unit, resulting in high manufacturing costs.
[0032] Therefore, this disclosure provides a self-powered DC circuit breaker. Under normal operating conditions, the energy storage element supplies power to the circuit breaker circuit via an independently provided power supply line. This avoids the high voltage in the high-voltage main circuit directly impacting the energy storage element, which would otherwise be caused by direct connection to the energy storage element, thus achieving high-voltage protection under energy storage element power supply conditions. Furthermore, under energy extraction conditions, the circuit breaker circuit can clamp the voltage across the energy storage element. Therefore, even if the energy storage element is directly connected to the high-voltage main circuit, voltage clamping can be achieved through the circuit breaker circuit, preventing excessive voltage across the energy storage element during charging, thus achieving high-voltage protection under energy storage element charging conditions. Therefore, this disclosure achieves high-voltage protection under both energy storage element power supply and charging conditions, eliminating the need for a high-voltage isolation device for the energy storage element, thereby reducing the manufacturing cost of the DC circuit breaker.
[0033] The embodiments will now be described in detail with reference to the accompanying drawings.
[0034] Figure 1 This is a schematic diagram of the structure of a self-powered DC circuit breaker provided in an embodiment of this disclosure, as shown below. Figure 1 As shown, the self-powered DC circuit breaker includes: a circuit breaker circuit 10 and an energy storage circuit 20.
[0035] The first terminal of the circuit breaker circuit 10 is connected to the input terminal 31, and the second terminal of the circuit breaker circuit 10 is connected to the output terminal 32.
[0036] Specifically, circuit breaker circuit 10 is connected to the high-voltage main circuit of the DC transmission system. The operating current in the high-voltage main circuit flows through the input terminal 31, circuit breaker circuit 10, and output terminal 32. In the event of a short-circuit fault in the DC transmission system, circuit breaker circuit 10 disconnects, thereby cutting off the high-voltage main circuit and preventing the large current surge caused by the short-circuit fault from impacting other loads connected to the high-voltage main circuit, thus protecting the entire system.
[0037] The energy storage circuit 20 includes an energy storage element 21 and a switching element 22; the first end of the energy storage element 21 is connected to the third end of the circuit breaker circuit 10, the second end of the energy storage element 21 is connected to the first end of the switching element 22, the second end of the switching element 22 is connected to the second end of the circuit breaker circuit 10, and the energy storage element 21 is also connected to the circuit breaker circuit 10 through a power supply line 23.
[0038] Under normal operating conditions of circuit breaker circuit 10, the switching element 22 is open, and the energy storage element 21 supplies power to circuit breaker circuit 10 through power supply line 23.
[0039] When the circuit breaker circuit 10 is in the energy extraction condition, the switching element 22 is turned on, the circuit breaker circuit 10 clamps the voltage across the energy storage element 21 and charges the energy storage element 21.
[0040] For example, under normal operating conditions, circuit breaker circuit 10 is conducting, and the high-voltage main circuit flows normally through the operating circuit. The external control module controls the switching element 22 to remain open, allowing the energy storage element 21 to supply power to the circuit breaker circuit 10 through an independently configured power supply line 23. Since the energy storage element 21 is supplied to the circuit breaker circuit 10 through an independently configured power supply line 23, rather than being directly connected to the high-voltage main circuit, this avoids the high voltage in the high-voltage main circuit directly impacting the energy storage element 21, thus achieving high-voltage protection for the energy storage element 21.
[0041] Under the power extraction condition of circuit breaker circuit 10, the external control module controls the switching element 22 to conduct, allowing the energy storage element 21 to be connected to the high-voltage main circuit through circuit breaker circuit 10. Circuit breaker circuit 10 draws power from the high-voltage main circuit to charge the energy storage element 21. The energy storage element 21 is connected in series with the switching element 22 and then connected between the third and second terminals of circuit breaker circuit 10. A voltage clamping device is provided between the third and second terminals of circuit breaker circuit 10, so that even if the energy storage element 21 is directly connected to the high-voltage main circuit, the voltage can be clamped by circuit breaker circuit 10 to prevent excessive voltage across the energy storage element 21 and achieve high-voltage protection for the energy storage element 21.
[0042] According to the embodiments of this disclosure, under normal operating conditions of the circuit breaker circuit 10, the energy storage element 21 supplies power to the circuit breaker circuit 10 through an independently provided power supply line 23. This avoids the high voltage in the high-voltage main circuit directly impacting the energy storage element 21 due to its direct connection to the high-voltage main circuit, thus achieving high-voltage protection under the power supply condition of the energy storage element 21. Furthermore, under the energy extraction condition of the circuit breaker circuit 10, the switching element 22 is turned on, connecting the energy storage element 21 to the high-voltage main circuit. The circuit breaker circuit 10 draws power from the high-voltage main circuit to charge the energy storage element 21, thereby enabling the circuit breaker circuit 10 and the energy storage element 21 to achieve self-energy extraction. Moreover, the circuit breaker circuit 10 can clamp the voltage across the energy storage element 21. Therefore, even if the energy storage element 21 is directly connected to the high-voltage main circuit, the circuit breaker circuit 10 can achieve voltage clamping, preventing excessive voltage across the energy storage element 21 during charging, thus achieving high-voltage protection under the charging condition of the energy storage element 21. Thus, this disclosure achieves high-voltage protection under the power supply and charging conditions of the energy storage element 21, thereby eliminating the need to install a high-voltage isolation device for the energy storage element 21 and reducing the manufacturing cost of the DC circuit breaker.
[0043] In some embodiments, the energy storage element 21 includes a plurality of energy storage devices; the plurality of energy storage devices are connected in series and / or in parallel.
[0044] For example, the energy storage device can be a supercapacitor or battery, or other device capable of both energy storage and power supply. Multiple energy storage devices in energy storage element 21 can be connected in series, thereby increasing the total voltage provided by energy storage element 21. Multiple energy storage devices in energy storage element 21 can also be connected in parallel, thereby increasing the total capacity of energy storage element 21. Furthermore, multiple energy storage devices in energy storage element 21 can be connected in series followed by parallel, or in parallel followed by series, thereby increasing both the total capacity and the total voltage provided by energy storage element 21.
[0045] In some embodiments, Figure 2 A schematic diagram of another self-powered DC circuit breaker provided in this disclosure embodiment is shown below. Figure 2 As shown, the circuit breaker circuit 10 includes: a first switching device 11 and a controllable voltage source 12.
[0046] The first terminal of the first switching device 11 is connected to the input terminal 31, the second terminal of the first switching device 11 is connected to the first terminal of the controllable voltage source 12 and the first terminal of the energy storage element 21, and the second terminal of the controllable voltage source 12 is connected to the output terminal 32 and the second terminal of the switching element 22.
[0047] The first switching device 11 and the controllable voltage source 12 are both connected to the power supply line 23.
[0048] When the switching element 22 is open, the energy storage element 21 is used to supply power to the first switching device 11 and the controllable voltage source 12 through the power supply line 23.
[0049] When the switching element 22 is turned on, the controllable voltage source 12 operates in voltage clamping mode, clamping the voltage across the energy storage element 21.
[0050] For example, when both the first switching device 11 and the controllable voltage source 12 are on, the high-voltage main circuit flows normally through the operating circuit. The external control module controls the switching element 22 to remain off, allowing the energy storage element 21 to supply power to the first switching device 11 and the controllable voltage source 12 through an independently configured power supply line 23. Since the energy storage element 21 supplies power to the first switching device 11 and the controllable voltage source 12 through an independently configured power supply line 23, rather than directly connecting the energy storage element 21 to the high-voltage main circuit, the high voltage in the high-voltage main circuit can be prevented from directly impacting the energy storage element 21, thus achieving high-voltage protection for the energy storage element 21.
[0051] When it is necessary to charge the energy storage element 21, the external control module controls the switching element 22 to conduct and controls the controllable voltage source 12 to operate in voltage clamping mode. At this time, the operating current in the high-voltage main circuit flows through the input terminal 31, the first switching device 11, the energy storage element 21, and the output terminal 32, so that the energy storage element 21 is connected to the high-voltage main circuit, and the operating current in the high-voltage main circuit charges the energy storage element 21. The energy storage element 21 and the conducting switching element 22 are connected in parallel with the controllable voltage source 12, so that when the energy storage element 21 is directly connected to the high-voltage main circuit, the controllable voltage source 12 clamps the voltage across the energy storage element 21, thereby preventing the voltage across the energy storage element 21 from becoming too high and realizing high-voltage protection for the energy storage element 21.
[0052] According to the embodiments of this disclosure, when both the first switching device 11 and the controllable voltage source 12 are turned on, the energy storage element 21 supplies power to the first switching device 11 and the controllable voltage source 12 through an independently provided power supply line 23. This avoids the high voltage in the high-voltage main circuit directly impacting the energy storage element 21 due to its direct connection to the high-voltage main circuit, thus achieving high-voltage protection under the power supply condition of the energy storage element 21. Furthermore, when it is necessary to charge the energy storage element 21, the switching device 22 is turned on, connecting the energy storage element 21 to the high-voltage main circuit. The operating current in the high-voltage main circuit charges the energy storage element 21, thereby enabling the energy storage element 21 to obtain its own energy. Moreover, the controllable voltage source 12 can clamp the voltage across the energy storage element 21. Therefore, even if the energy storage element 21 is directly connected to the high-voltage main circuit, the voltage can be clamped through the controllable voltage source 12, preventing the voltage across the energy storage element 21 from becoming too high during charging, thus achieving high-voltage protection under the charging condition of the energy storage element 21. Thus, this disclosure achieves high-voltage protection under the power supply and charging conditions of the energy storage element 21, thereby eliminating the need to install a high-voltage isolation device for the energy storage element 21 and reducing the manufacturing cost of the DC circuit breaker.
[0053] In the event of a short-circuit fault in the DC transmission system, the controllable voltage source 12 generates an oscillating current through excitation, causing the current in the branch containing the first switching device 11 and the controllable voltage source 12 to cross zero. Under these circumstances, the switching element 22 remains in the open state, thereby preventing the energy storage element 21 from being connected to the high-voltage main circuit.
[0054] In some embodiments, Figure 3 This is a schematic diagram of a controllable voltage source provided in an embodiment of the present disclosure, as shown below. Figure 3 As shown, the controllable voltage source 12 includes multiple power electronic devices 121; the multiple power electronic devices 121 are connected in series with each other.
[0055] For example, connecting multiple power electronic devices 121 in series can improve the high voltage withstand capability of the controllable voltage source 12.
[0056] Figure 4 A schematic diagram of another controllable voltage source provided in this disclosure embodiment is shown below. Figure 4 As shown, the controllable voltage source 12 includes multiple power electronic devices 121; the multiple power electronic devices 121 are connected in parallel with each other.
[0057] For example, connecting multiple power electronic devices 121 in parallel can improve the current carrying capacity of the controllable voltage source 12.
[0058] Figure 5 This is a schematic diagram of another controllable voltage source provided in an embodiment of the present disclosure. The controllable voltage source includes a plurality of power electronic devices 121; some of the power electronic devices 121 are connected in series with each other, and other power electronic devices 121 are connected in parallel with each other.
[0059] For example, connecting some power electronic devices 121 in series with each other and connecting other power electronic devices 121 in parallel with each other can improve the high voltage resistance and current carrying capacity of the controllable voltage source 12.
[0060] It should be noted that, Figure 5 The connection relationship between multiple power electronic devices 121 is only shown as an example. The specific connection method needs to be determined according to the actual situation, and no specific limitation is made here.
[0061] The power electronic device 121 can employ fully controlled power electronic devices such as insulated-gate bipolar transistors (IGBTs), integrated gate-commutated thyristors (IGCTs), and injection-enhanced gate transistors (IEGTs).
[0062] The control terminals of multiple power electronic devices 121 and the control terminals of switching elements 22 are all connected to the control module (not shown in the figure).
[0063] The control module is used to control multiple power electronic devices 121 to disconnect when the electrical energy of the energy storage element 21 is less than or equal to a first electrical energy threshold, and to control the switching element 22 to turn on when the multiple power electronic devices 121 are disconnected.
[0064] For example, the control module can detect the electrical energy in the energy storage element 21. If the electrical energy in the energy storage element 21 is less than or equal to a first electrical energy threshold, it is confirmed that the energy storage element 21 needs to be charged. The control module first controls multiple power electronic devices 121 to disconnect, so that the body diode of the power electronic device 121, or the diode connected in parallel with the power electronic device 121, is connected. At this time, the body diode of the power electronic device 121, or the diode connected in parallel with the power electronic device 121, is used as a clamping circuit, so that the circuit breaker circuit is used for voltage clamping and loses its circuit breaker function for a short time. When multiple power electronic devices 121 are completely disconnected, that is, when multiple power electronic devices 121 can achieve the clamping function, the control module then controls the switching element 22 to conduct, so that the energy storage element 21 is connected to the high-voltage main circuit, and the operating current in the high-voltage main circuit charges the energy storage element 21. Therefore, when the energy storage element 21 is directly connected to the high-voltage main circuit, the disconnected multiple power electronic devices 121 clamp the voltage across the energy storage element 21, thereby preventing excessive voltage across the energy storage element 21 and achieving high-voltage protection for the energy storage element 21. Furthermore, by controlling the switching element 22 to turn on when multiple power electronic devices 121 are disconnected, the problem of high-voltage damage to the energy storage element 21 caused by connecting it to the high-voltage main circuit before the multiple power electronic devices 121 have achieved their voltage clamping function can be avoided. Therefore, high-voltage isolation can be achieved without setting a high-voltage isolation device for the energy storage element 21, thereby reducing the manufacturing cost of the DC circuit breaker.
[0065] The control module is also used to control the switching element 22 to open when the electrical energy of the energy storage element 21 is greater than the second electrical energy threshold, and to control the multiple power electronic devices 121 to turn on when the switching element 22 is open.
[0066] For example, when the electrical energy of the energy storage element 21 exceeds the second electrical energy threshold, it is confirmed that the energy storage element 21 can supply power. At this time, the control module first controls the switching element 22 to open, disconnecting the connection between the energy storage element 21 and the high-voltage main circuit. Subsequently, the control module controls multiple power electronic devices 121 to turn on, restoring the circuit breaker circuit 10 to its circuit breaker function and removing its voltage clamping function. At this time, the energy storage element 21 resumes supplying power to the first switching device 11 and the controllable voltage source 12 through the power supply line 23, and the energy storage element 21 can also additionally supply power to the control module. This disclosure controls multiple power electronic devices 121 to conduct after the switching element 22 is opened, so that the circuit breaker circuit 10 can restore the circuit breaker function. If the multiple power electronic devices 121 have already conducted and lost their voltage clamping function before the switching element 22 is opened, the energy storage element 21 will be damaged by high voltage due to direct connection to the high voltage main circuit. Therefore, by controlling multiple power electronic devices 121 to conduct after the switching element 22 is opened, this disclosure can prevent the energy storage element 21 from being disconnected from the high voltage main circuit before the multiple power electronic devices 121 lose their voltage clamping function, thereby preventing the energy storage element from being damaged by high voltage. Therefore, high voltage isolation can be achieved without setting a high voltage isolation device for the energy storage element 21, thereby reducing the manufacturing cost of the DC circuit breaker.
[0067] In the event of a short-circuit fault in the DC transmission system, multiple power electronic devices 121 generate oscillating current through high-frequency switching, causing the current in the branch containing the first switching device 11 and the controllable voltage source 12 to cross zero. Under these conditions, the switching element 22 remains in the open state, thereby preventing the energy storage element 21 from being connected to the high-voltage main circuit.
[0068] It should be noted that the first energy threshold is less than the second energy threshold.
[0069] In some embodiments, see continue to see Figure 2 The self-powered DC circuit breaker also includes a second switching device 40.
[0070] The first terminal of the second switching device 40 is connected to the first terminal of the controllable voltage source 12, the second terminal of the second switching device 40 is connected to the second terminal of the controllable voltage source 12, and the control terminal of the second switching device 40 is connected to the control module (not shown in the figure).
[0071] The control module is used to control the second switching device 40 to open when the electrical energy of the energy storage element 21 is less than or equal to the third electrical energy threshold, and to control the controllable voltage source 12 to operate in voltage clamping mode when the second switching device 40 is open. The conduction loss of the second switching device 40 is less than the conduction loss of the controllable voltage source 12.
[0072] For example, the second switching device 40 is connected in parallel with the controllable voltage source 12. When both the second switching device 40 and the controllable voltage source 12 are turned on, the operating current in the high-voltage main circuit flows through the input terminal 31 and the first switching device 11, and is shunted at the second terminal of the first switching device 11. The shunted current flows to the output terminal 32 through the second switching device 40 and the controllable voltage source 12, respectively. Since the conduction loss of the second switching device 40 is less than that of the controllable voltage source 12, this disclosure can reduce conduction losses by setting the second switching device 40 to conduct the operating current of the high-voltage main circuit.
[0073] When the electrical energy of the energy storage element 21 is less than or equal to the third electrical energy threshold, the energy storage element 21 needs to be charged. The control module first controls the second switching device 40 to open, causing the operating current flowing through the second switching device 40 to transfer to the controllable voltage source 12. With the second switching device 40 open, the controllable voltage source 12 is then controlled to operate in voltage clamping mode. If the controllable voltage source 12 is controlled to operate in voltage clamping mode first, this will cause the operating current on the controllable voltage source 12 to transfer to the second switching device 40. When the second switching device 40 is open, if the operating current is transferred through the arc voltage naturally generated at the switch break of the second switching device 40, it will cause the operating current to be uncontrollable. The operating current will try to flow through other stray paths instead of charging the energy storage element 21. Therefore, this disclosure first turns off the second switching device 40 and then turns off the controllable voltage source 12, relying on the characteristic of the controllable voltage source 12 to controllably transfer the operating current to the energy storage element 21 to charge the energy storage element 21.
[0074] It should be noted that the third energy threshold can be the same as the first energy threshold.
[0075] In some embodiments, the second switching device includes a high-arc-voltage mechanical switch.
[0076] For example, high arc voltage mechanical switches include magnetic blow mechanical switches or multi-break mechanical switches to enable the provision of sufficiently high arc voltage at the switch breaks.
[0077] The control module is used to control the high-arc voltage mechanical switch to open when the electrical energy of the energy storage element is less than or equal to the third electrical energy threshold, and to detect the switch break state of the high-arc voltage mechanical switch; when the switch break state of the high-arc voltage mechanical switch can withstand transient overvoltage, it controls the controllable voltage source to work in voltage clamping mode.
[0078] For example, a high-arc voltage mechanical switch is connected in parallel with a controllable voltage source. When both the high-arc voltage mechanical switch and the controllable voltage source are conducting, the operating current in the high-voltage main circuit flows through the input terminal and the first switching device, and is shunted at the second terminal of the first switching device. The shunted current then flows to the output terminal through the high-arc voltage mechanical switch and the controllable voltage source, respectively. Since the conduction loss of the high-arc voltage mechanical switch is less than that of the controllable voltage source, this disclosure can reduce conduction losses by using the high-arc voltage mechanical switch to conduct the operating current of the high-voltage main circuit.
[0079] When the energy of the energy storage element is less than or equal to the third energy threshold, the energy storage element needs to be charged. The control module first controls the high-arc voltage mechanical switch to open. An arc voltage exists at the switch port of the high-arc voltage mechanical switch, causing the operating current originally flowing through the high-arc voltage mechanical switch to be transferred to the controllable voltage source. With the high-arc voltage mechanical switch open, the controllable voltage source is then controlled to operate in voltage clamping mode. If the controllable voltage source is controlled to operate in voltage clamping mode first, this would cause the operating current on the controllable voltage source to be transferred to the high-arc voltage mechanical switch. When the high-arc voltage mechanical switch is open, if the operating current is transferred through the arc voltage naturally generated at the switch break, it would lead to uncontrollable operating current, which would attempt to flow through other stray paths instead of charging the energy storage element. Therefore, this disclosure first turns off the high-arc voltage mechanical switch, then turns off the controllable voltage source, relying on the controllable voltage source's ability to control the operating current, so that the operating current is controllably transferred to the energy storage element to charge it.
[0080] In some embodiments, the switching element includes a thyristor.
[0081] In some embodiments, the switching element includes a trigger gap electrode.
[0082] For example, the switching element is turned on by the electric arc between the two trigger gap electrodes, and the switching element is turned off by stopping the electric arc generated between the two trigger gap electrodes.
[0083] In some embodiments, see continue to see Figure 2 The circuit breaker circuit 10 includes a resonant unit 13.
[0084] The resonant unit 13 includes a first inductor L1 and a first capacitor C1.
[0085] The first end of the first inductor L1 is connected to the input terminal 31, the second end of the first inductor L1 is connected to the first end of the first capacitor C1, and the second end of the first capacitor C1 is connected to the output terminal 32.
[0086] For example, the first inductor L1 and the first capacitor C1 form a resonant unit 13, which can provide resonant conditions for the current-carrying branch of the circuit breaker circuit 10.
[0087] In some embodiments, see continue to see Figure 2 The circuit breaker circuit 10 includes an energy dissipation unit 14; the first end of the energy dissipation unit 14 is connected to the input terminal 31, and the second end of the energy dissipation unit 14 is connected to the output terminal 32.
[0088] For example, the energy dissipation unit 14 may be, for example, a metal oxide surge arrester. The energy dissipation unit 14 is capable of absorbing the remaining energy in the circuit breaker circuit 10 and of limiting the overvoltage generated during the switching process of the circuit breaker circuit 10, thereby ensuring the safe operation of the circuit breaker circuit 10.
[0089] 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. A self-powered DC circuit breaker, characterized in that, include: A circuit breaker circuit, wherein the first terminal of the circuit breaker circuit is connected to the input terminal, and the second terminal of the circuit breaker circuit is connected to the output terminal; An energy storage circuit includes an energy storage element and a switching element; a first terminal of the energy storage element is connected to a third terminal of the circuit breaker circuit, a second terminal of the energy storage element is connected to a first terminal of the switching element, a second terminal of the switching element is connected to a second terminal of the circuit breaker circuit, and the energy storage element is also connected to the circuit breaker circuit via a power supply line. Under normal operating conditions of the circuit breaker circuit, the switching element is open, and the energy storage element supplies power to the circuit breaker circuit through the power supply line; When the circuit breaker circuit is in the energy extraction condition, the switching element is turned on, the circuit breaker circuit clamps the voltage across the energy storage element and charges the energy storage element.
2. The self-powered DC circuit breaker according to claim 1, characterized in that, The circuit breaker circuit includes: a first switching device and a controllable voltage source; The first terminal of the first switching device is connected to the input terminal, the second terminal of the first switching device is connected to the first terminal of the controllable voltage source and the first terminal of the energy storage element, and the second terminal of the controllable voltage source is connected to the output terminal and the second terminal of the switching element. The first switching device and the controllable voltage source are both connected to the power supply line; When the switching element is open, the energy storage element is used to supply power to the first switching device and the controllable voltage source through the power supply line; When the switching element is turned on, the controllable voltage source operates in voltage clamping mode, clamping the voltage across the energy storage element.
3. The self-powered DC circuit breaker according to claim 2, characterized in that, The controllable voltage source includes multiple power electronic devices; the multiple power electronic devices are connected in series and / or in parallel, and the control terminals of the multiple power electronic devices and the control terminals of the switching element are all connected to the control module. The control module is used to control multiple power electronic devices to disconnect when the electrical energy of the energy storage element is less than or equal to a first electrical energy threshold. Furthermore, when multiple power electronic devices are disconnected, the switching element is controlled to turn on; The control module is also used to control the switching element to disconnect when the electrical energy of the energy storage element is greater than the second electrical energy threshold. Furthermore, when the switching element is open, the plurality of power electronic devices are controlled to turn on; Wherein, the first energy threshold is less than the second energy threshold.
4. The self-powered DC circuit breaker according to claim 2 or 3, characterized in that, It also includes a second switching device; The first terminal of the second switching device is connected to the first terminal of the controllable voltage source, the second terminal of the second switching device is connected to the second terminal of the controllable voltage source, and the control terminal of the second switching device is connected to the control module; The control module is used to control the second switching device to disconnect when the electrical energy of the energy storage element is less than or equal to a third electrical energy threshold. Furthermore, when the second switching device is disconnected, the controllable voltage source is controlled to operate in voltage clamping mode; The conduction loss of the second switching device is less than that of the controllable voltage source.
5. The self-powered DC circuit breaker according to claim 4, characterized in that, The second switching device includes a high-arc voltage mechanical switch; The control module is used to control the high-arc voltage mechanical switch to open when the electrical energy of the energy storage element is less than or equal to the third electrical energy threshold, and to detect the switch break status of the high-arc voltage mechanical switch. When the switching state of the high-arc voltage mechanical switch can withstand transient overvoltage, the controllable voltage source is controlled to operate in voltage clamping mode.
6. The self-powered DC circuit breaker according to claim 5, characterized in that, The high-arc-voltage mechanical switch includes a magnetic blowout mechanical switch or a multi-break mechanical switch.
7. The self-powered DC circuit breaker according to claim 1, characterized in that, The switching element includes a thyristor or a trigger gap electrode.
8. The self-powered DC circuit breaker according to claim 1, characterized in that, The circuit breaker circuit includes a resonant unit; The resonant unit includes a first inductor and a first capacitor; The first end of the first inductor is connected to the input terminal, the second end of the first inductor is connected to the first end of the first capacitor, and the second end of the first capacitor is connected to the output terminal.
9. The self-powered DC circuit breaker according to claim 1, characterized in that, The circuit breaker circuit includes an energy-consuming unit; The first end of the energy-consuming unit is connected to the input end, and the second end of the energy-consuming unit is connected to the output end.
10. The self-powered DC circuit breaker according to claim 1, characterized in that, The energy storage element includes multiple energy storage devices; the multiple energy storage devices are connected in series and / or in parallel. The energy storage device includes at least a supercapacitor or a battery.