A peak shaving arrester and circuit breaker

Abstract

This application belongs to the field of surge arresters, specifically disclosing a peak-shaving surge arrester and a circuit breaker. This application employs a technical approach consisting of a first surge arrester module responding to the voltage change rate and a second surge arrester module responsible for energy absorption connected in parallel. This solves the problem of traditional surge arresters' delayed response due to reliance on voltage amplitude triggering, and their inability to effectively suppress high-frequency voltage spikes. The first surge arrester module instantaneously conducts by directly sensing a sharp voltage change, actively clamping the initial peak value of transient overvoltage and overcoming the hysteresis of traditional solutions. Subsequently, after the spike is suppressed and the transient overvoltage due to the decrease in the voltage change rate is suppressed, the second surge arrester module seamlessly takes over and absorbs the residual overvoltage energy, thereby achieving synergy between rapid active peak shaving and energy dissipation. Compared with existing technologies, this solution fundamentally avoids the dynamic breakdown threat to the main semiconductor valve, significantly improving the safety and reliability of the hybrid DC circuit breaker's breaking process.

Description

Technical Field

[0001] This application belongs to the field of surge arresters, specifically relating to a peak-shaving surge arrester and a circuit breaker. Background Technology

[0002] The transient voltage overshoot problem faced by hybrid DC circuit breakers when interrupting fault current is caused by the coupling of extremely high current change rate and inherent stray inductance.

[0003] To achieve rapid current limiting, the main semiconductor valve of the circuit breaker needs to interrupt fault currents of several thousand amperes within an extremely short time, resulting in a limiting current change rate on the order of kA / μs. When this change rate flows through the unavoidable stray inductance in the power circuit, it induces a large-amplitude inductive voltage spike according to the law of electromagnetic induction. This voltage spike is directly superimposed on the steady-state voltage of the system across the semiconductor valve, making it highly susceptible to local avalanche breakdown during the dynamic shutdown process, leading to thermal runaway and permanent damage, jeopardizing the success of the entire shutdown process and equipment safety. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this application is to provide a surge arrester and circuit breaker, which aims to solve the problem that existing surge arresters have huge inductive peak voltages and poor safety in circuit breaker applications.

[0005] The first aspect of this application relates to a surge arrester, comprising: a first surge arrester module and a second surge arrester module; a first terminal of the first surge arrester module is connected to a first terminal of the second surge arrester module and a first terminal of a protected device; a second terminal of the first surge arrester module is connected to a second terminal of the second surge arrester module and a second terminal of the protected device; the first surge arrester module is configured to conduct a discharge channel in response to a port voltage change rate greater than a preset threshold to suppress transient overvoltage; the second surge arrester module is configured to absorb energy after the transient overvoltage is suppressed.

[0006] In one embodiment, the first surge protection module includes: a response switch unit and an energy absorption unit; a first end of the response switch unit is connected to a first end of the protected device; a second end of the response switch unit is connected to a first end of the energy absorption unit; a second end of the energy absorption unit is connected to a second end of the protected device to form a discharge channel; the response switch unit is configured to conduct the discharge channel in response to a port voltage change rate greater than a preset threshold; the energy absorption unit is configured to absorb energy to suppress transient overvoltage when the discharge channel is conducted.

[0007] In one embodiment, the response switch unit includes: a plurality of reverse blocking double-ended solid-state thyristors; the anodes and cathodes of the plurality of reverse blocking double-ended solid-state thyristors are connected in series from end to end, the first end of the series connection is connected to the first end of the protected device, and the last end of the series connection is connected to the first end of the energy absorption unit.

[0008] In one embodiment, the number of reverse blocking double-ended solid thyristors is determined based on the port voltage threshold of the first lightning protection module.

[0009] In one embodiment, the application scenario of the surge arrester is determined by the conduction threshold of the reverse blocking double-ended solid thyristor.

[0010] In one embodiment, the energy absorption unit includes: a first resistor, a first capacitor, and a second resistor; a first end of the first resistor is connected to a first end of the first capacitor and a second end of the response switch unit; a second end of the first resistor is connected to a second end of the first capacitor and a first end of the second resistor; and a second end of the second resistor is connected to a second end of the protected device.

[0011] In one embodiment, the capacitance value of the first capacitor satisfies the following constraint: ; in, That is the capacitance value of the first capacitor; It is a stray inductance in the circuit; It is the maximum short-circuit current; It is the maximum voltage spike margin.

[0012] In one embodiment, the resistance value of the second resistor satisfies the following constraint: ; in, It is the resistance value of the second resistor; It is a loop capacitor; It is a stray inductance in the circuit; It is the maximum short-circuit current; It is the maximum voltage spike margin.

[0013] In one embodiment, the second lightning protection module includes: a metal oxide surge arrester; a first end of the metal oxide surge arrester is connected to a first end of the protected device; and a second end of the metal oxide surge arrester is connected to a second end of the protected device.

[0014] The second aspect of this application relates to a circuit breaker, comprising: a protected device and a surge arrester of the first aspect; the surge arrester is connected in parallel with the protected device and then connected in series in the working circuit.

[0015] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art: This application solves the problems of traditional surge arresters relying on voltage amplitude triggering and response delay, which cannot effectively suppress nanosecond-level high-frequency peak voltages caused by extremely high di / dt, and the contradiction between fast response and energy tolerance of a single device, by adopting a technical means consisting of a first surge arrester module that is turned on by the voltage change rate of the response port and a second surge arrester module that is subsequently put into operation to absorb energy.

[0016] Specifically, the first surge arrester module directly senses the sharp rise in voltage that characterizes the fault shutdown by detecting the rate of change of voltage, thereby achieving near-delayed early conduction and actively suppressing the initial peak value of transient overvoltage. This overcomes the drawbacks of traditional amplitude-triggered surge arresters, such as delayed response and pre-formation spikes. Subsequently, after the spike is suppressed and the rate of change of port voltage decreases, the second surge arrester module seamlessly takes over and absorbs the residual overvoltage energy in the system, thus completing the coordinated protection process from rapid active peak reduction to reliable energy discharge.

[0017] Compared with existing technologies, this solution effectively clamps the most dangerous instantaneous voltage spikes when a hybrid DC circuit breaker is interrupted, fundamentally avoiding the risk of dynamic breakdown of the main semiconductor valve. At the same time, it optimizes the performance targets of each module through functional separation, and ultimately significantly improves the safety and reliability of the system while ensuring the same or even stronger clamping protection effect. Attached Figure Description

[0018] Figure 1 This is a structural block diagram of a surge arrester provided in an embodiment of this application; Figure 2 This is another structural block diagram of the surge arrester provided in the embodiments of this application; Figure 3 This is a schematic diagram of the topology of the circuit breaker provided in the embodiments of this application; Figure 4 This is a comparison chart of peak reduction effects at a 6kV voltage level provided in the embodiments of this application; Figure 5 This is a comparison chart of peak reduction effects at a 10kV voltage level provided in the embodiments of this application; Figure 6 This application provides a Fourier decomposition spectrum diagram of a 10kV voltage level surge arrester using only metal oxide surge arresters; Figure 7 This application provides a Fourier decomposition power spectral density diagram of a 10kV voltage level using only metal oxide surge arresters; Figure 8 This is a Fourier decomposition spectrum of an improved surge arrester with a voltage level of 10kV provided in an embodiment of this application; Figure 9This is a Fourier decomposition power spectral density diagram of an improved surge arrester with a voltage level of 10kV provided in an embodiment of this application.

[0019] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 10 is the first lightning protection module; 11 is the response switch unit; 12 is the energy absorption unit; 20 is the second lightning protection module. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0021] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone. In this application, the symbol " / " indicates that the related objects are in an "or" relationship, for example, A / B means A or B.

[0022] In this application, the terms "first" and "second," etc., are used to distinguish different objects, not to describe a specific order of objects. For example, "first response message" and "second response message," etc., are used to distinguish different response messages, not to describe a specific order of response messages.

[0023] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0024] In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more, for example, multiple processing units means two or more processing units, multiple elements means two or more elements, etc.

[0025] Existing surge arresters suffer from significant inductive voltage spikes in circuit breaker applications, resulting in poor safety. Therefore, this application proposes a peak-shaving surge arrester. Please refer to... Figure 1 , Figure 1 This is a structural block diagram of a surge arrester provided in an embodiment of this application.

[0026] In this embodiment, the surge arrester includes: a first surge arrester module 10 and a second surge arrester module 20.

[0027] Understandably, a surge arrester is a composite overvoltage protection device. Its core function is to achieve rapid clamping of fast transient overvoltages and absorption and discharge of subsequent energy through the timing coordination of different internal functional modules.

[0028] The first surge arrester module and the second surge arrester module are the two core functional units constituting this composite device. The first surge arrester module 10 and the second surge arrester module 20 are connected in parallel. Specifically, the first end of the first surge arrester module 10 is electrically interconnected with the first end of the second surge arrester module 20, and together they serve as one input / output terminal of the entire surge arrester, used to connect to the protected device, such as the first end of the motor winding terminal on the load side of the circuit breaker. Similarly, the second end of the first surge arrester module 10 is electrically interconnected with the second end of the second surge arrester module 20, and together they serve as another input / output terminal of the surge arrester, used to connect to the second end of the protected device.

[0029] That is, the first terminal of the first surge protection module 10 is connected to the first terminal of the second surge protection module 20 and the first terminal of the protected device, respectively; the second terminal of the first surge protection module 10 is connected to the second terminal of the second surge protection module 20 and the second terminal of the protected device, respectively. This parallel connection means that the two modules bear the same terminal voltage, but can function at different stages according to their own electrical characteristics.

[0030] It should be noted that the first surge protection module 10 is configured to conduct the discharge channel in response to the port voltage change rate being greater than a preset threshold in order to suppress transient overvoltage; the second surge protection module 20 is configured to absorb energy after the transient overvoltage is suppressed.

[0031] Understandably, the core function of the first surge protection module 10 is to quickly respond to steep voltage pulses. Its configuration to activate the discharge channel in response to a port voltage change rate exceeding a preset threshold means that the module has a conduction characteristic sensitive to the voltage change rate (du / dt). When the protected circuit experiences a transient overvoltage with an extremely high rate of change due to a sudden current change, the module can quickly activate within a very short time, establishing a low-impedance discharge channel, thereby clipping the voltage peak across the protected device and limiting it to a lower level.

[0032] Understandably, the preset threshold here is a characteristic parameter determined by the internal physical structure of the module. For example, the module could be a semiconductor switching device with special doping, whose breakdown or turn-on voltage is positively correlated with the voltage rise rate. Its function of suppressing transient overvoltages is mainly achieved by quickly providing a bypass to prevent high-amplitude voltage spikes from building up on the protected device.

[0033] Understandably, the core function of the second surge protector module 20 is to absorb and dissipate energy. Its configuration to absorb energy after transient overvoltages are suppressed describes the cooperative working sequence of the two modules. When the first surge protector module 10 quickly turns on, it discharges the initial extremely high current spike, but the remaining energy stored in the system inductor still needs to be released. Although the amplitude of the overvoltage is limited at this time, its duration may be relatively long. After the first surge protector module 10 turns on, its arc voltage drop is usually low and may not be able to effectively dissipate all the energy. At this point, the second surge protector module 20 begins to take over the operation.

[0034] Understandably, the second surge arrester module 20 can be a metal oxide surge arrester (MOV). In the initial stage of an overvoltage event, because the MOV's conduction response is slightly slower than the first module, or the initial voltage is clamped below the MOV's startup voltage by the first module, the MOV may not fully activate. Once the transient overvoltage is suppressed, the residual energy voltage in the circuit will be applied to the MOV, causing it to conduct and enter the absorption state. The dominant absorption path shifts from the first surge arrester module 10 to the second surge arrester module 20, dissipating the remaining inductor energy as heat, thereby completely quelling the overvoltage oscillation.

[0035] In summary, this embodiment of the application achieves a temporal division of labor and complementary advantages by connecting a first surge protection module with a fast voltage change rate response characteristic and a second surge protection module with a large energy absorption capacity in parallel. The first module operates first, responsible for suppressing the steep voltage front and initial peak value; the second module operates subsequently, responsible for absorbing and dissipating energy to prevent the voltage from rising again. This structure effectively overcomes the shortcomings of a single MOV response being relatively lagging due to stray inductance and the insufficient energy dissipation capacity of a single discharge tube device, providing more comprehensive and reliable protection against ultra-fast transient overvoltages generated by circuit breakers interrupting inductive loads.

[0036] Furthermore, this application provides an improved embodiment, further illustrating the first lightning protection module 10. Please refer to... Figure 2 , Figure 2 This is another structural block diagram of the surge arrester provided in the embodiments of this application.

[0037] In this embodiment, the first lightning protection module 10 includes a response switch unit 11 and an energy absorption unit 12.

[0038] The first end of the response switch unit 11 is connected to the first end of the protected device; the second end of the response switch unit 11 is connected to the first end of the energy absorption unit 12; and the second end of the energy absorption unit 12 is connected to the second end of the protected device to form a discharge channel.

[0039] Understandably, this series connection between the response switch unit 11 and the energy absorption unit 12 together forms a complete discharge channel from the high-voltage side to the low-voltage side of the protected device. This structure means that the conduction of the discharge channel is controlled by the response switch unit 11, and once conducted, the inrush current flowing through the channel will mainly flow through the energy absorption unit 12, which will then perform the functions of limiting voltage and absorbing energy.

[0040] It should be noted that the response switch unit 11 is configured to conduct the discharge channel in response to the port voltage change rate being greater than a preset threshold; the energy absorption unit 12 is configured to absorb energy to suppress transient overvoltage when the discharge channel is conducted.

[0041] Understandably, a key characteristic of the response switch unit 11 is that it conducts in response to a port voltage change rate exceeding a preset threshold. This means that the unit has a trigger threshold for the voltage change rate (du / dt). When the voltage applied across it rises faster than this preset threshold, regardless of whether the absolute value of the voltage has already reached a high level, the unit will rapidly transition from a high-resistance state to a low-resistance state, thereby opening the discharge path. This unit can effectively sense almost vertically rising voltage fluctuations caused by circuit breaker current throttling.

[0042] Understandably, the energy absorption unit 12 is configured to immediately begin operation after the response switch unit 11 is turned on and the discharge channel is established, in order to absorb energy and suppress transient overvoltages. Its function is to provide a stable, controlled clamping voltage when current flows through it, limiting the overvoltage peak to a safe level while converting electromagnetic energy into heat. This unit typically exhibits nonlinear volt-ampere characteristics.

[0043] This improved embodiment achieves more precise and reliable control by refining the first surge protection module 10 into a cascaded response switch unit 11 and an energy absorption unit 12. The response switch unit is specifically responsible for rapid detection and circuit connection, and its sensitivity to dv / dt ensures immediate response to the fastest threats; while the independent energy absorption unit is specifically responsible for establishing a stable clamping voltage and dissipating energy. This functionally separated design provides a more precise voltage clamping level compared to a single-function discharge tube; and a faster operating speed compared to a standalone MOV. This series structure works together to act rapidly within the initial microseconds of overvoltage occurrence, buying time and creating favorable conditions for the full operation of the subsequent second surge protection module 20, thereby constructing a hierarchical and time-sequential integrated protection system.

[0044] Based on the above embodiments, this application provides a specific implementation of a peak-shaving surge arrester applied to a circuit breaker. Please refer to... Figure 3 , Figure 3This is a schematic diagram of the topology of the circuit breaker provided in the embodiments of this application.

[0045] In this embodiment, the response switch unit 11 includes: a plurality of reverse blocking diode thyristors (RBDTs); the anodes and cathodes of the plurality of reverse blocking diode thyristors are connected in series from end to end, the first end of the series connection is connected to the first end of the protected device, and the last end of the series connection is connected to the first end of the energy absorption unit 12.

[0046] It is understandable that a reverse-blocking double-ended solid-state thyristor (RBDT) is a semiconductor controllable switching device with symmetrical blocking characteristics. Its reverse blocking characteristic means that when a reverse voltage is applied between the anode and cathode, the device remains in the off state until it is triggered. Its double-ended nature refers to the fact that the device has two main terminals: an anode and a cathode. Multiple such devices are connected in series, with the anode and cathode connected sequentially. That is, the cathode of the first device is connected to the anode of the second device, the cathode of the second device is connected to the anode of the third device, and so on. The first end of this series chain, i.e., the anode of the first device, is connected to the first end of the protected device, i.e., the high-voltage side, while the last end of the series chain, i.e., the cathode of the last device, is connected to the first end of the energy absorption unit 12. This series structure allows all RBDT devices to share the voltage applied across the response switching unit 11.

[0047] Understandably, the core purpose of using multiple reverse-blocking double-ended solid-state thyristors in series is to improve the static voltage withstand capability of the entire switching unit. Individual devices have limited withstand voltage; by connecting them in series, the system voltage can be evenly distributed to each device, ensuring reliable turn-off during normal operation. Its triggering mechanism relies entirely on the intrinsic characteristics of the semiconductor structure: when a rapidly rising transient overvoltage is applied across the series-connected devices, the junction capacitance of the reverse-biased junction inside each device will generate a significant displacement current due to the rapid voltage change. This displacement current flows through the semiconductor region near the junction, equivalent to the current injected into the trigger electrode. When dv / dt is high enough that this displacement current exceeds the critical conduction value required for the device, it will directly trigger the regenerative positive feedback of the PNPN structure inside the device, causing the device to rapidly switch to a fully conducting state within nanoseconds. The entire process is a purely physical effect, requiring no form of detection circuitry for signal judgment and amplification.

[0048] Therefore, this application abandons the active drive scheme and cleverly utilizes the extremely high voltage rise rate excited by stray inductance at the moment of switching branch turn-off as the natural trigger signal of RBDT. This fully leverages the gateless, dv / dt triggered mechanism of RBDT, achieving nanosecond-level turn-on during commutation transient overvoltage and improving dynamic response speed.

[0049] Understandably, when multiple RBDTs connected in series are simultaneously turned on due to their high dv / dt, the response switching unit 11 becomes a low-impedance path. At this time, the transient large current is rapidly directed to the energy absorption unit 12. The energy absorption unit 12 then clamps the voltage and absorbs energy.

[0050] It should be noted that the number of reverse blocking double-ended solid-state thyristors is determined by the port voltage threshold of the first surge arrester module 10. Meanwhile, the application scenario of the surge arrester is determined by the conduction threshold of the reverse blocking double-ended solid-state thyristors.

[0051] Understandably, the number of RBDTs connected in series is determined by the port voltage threshold required to be achieved by the first surge protection module 10. The port voltage threshold here refers to the highest power frequency voltage or DC voltage peak value that the first surge protection module 10 can reliably withstand over a long period without false conduction or breakdown in the non-triggered state. This threshold must be higher than the highest voltage to ground or inter-electrode voltage of the protected line during normal steady-state operation, with sufficient safety margin.

[0052] Understandably, since a single reverse-blocking double-ended solid-state thyristor has its rated reverse blocking voltage and forward blocking voltage, the total static voltage withstand capability of multiple such devices, connected in series end-to-end with anode and cathode connected together, is theoretically the sum of the blocking voltages of each individual device. Therefore, in the design, the required number N in series should satisfy: N ≥ port voltage threshold / withstand voltage of a single device. For example, if the line voltage of the protected system is 10kV, and the blocking voltage of a single RBDT is 2kV, then at least 5 RBDTs need to be connected in series. This design ensures that the series branches can be reliably shut off during normal system operation, maintaining leakage current at an extremely low level.

[0053] Understandably, the specific application scenarios of surge arresters are mainly determined by the conduction threshold of the selected reverse-blocking double-ended solid-state thyristor. The conduction threshold specifically refers to the minimum voltage change rate required for the device to transition from an off state to a fully on state, typically measured in kV / μs or V / ns. This parameter is an intrinsic physical characteristic of the device, dependent on factors such as the junction capacitance and doping concentration of its internal semiconductor structure. Different overvoltage phenomena exhibit drastically different voltage rise rates (dv / dt). For example, the wavefront rise rate of ultrafast transient overvoltages generated by a vacuum circuit breaker interrupting an inductive load can reach tens to hundreds of kV / μs; while the wavefront of lightning-induced overvoltages is generally on the order of 1-10 kV / μs; and the wavefront of switching overvoltages is relatively slower.

[0054] Therefore, for precise protection, it is necessary to select an RBDT with a corresponding on-threshold based on the wavefront characteristics of the expected overvoltage. For ultra-fast transient overvoltages, a model with a higher on-threshold (e.g., >50 kV / μs) should be selected to avoid malfunctions in response to slowly rising normal operating voltages or interference signals; if the main protection is against lightning surges, a model with a lower on-threshold (e.g., 1-20 kV / μs) can be selected to ensure a reliable response to lightning voltages.

[0055] In this embodiment, the circuit topology of the energy absorption unit 12 can be equivalent to: Figure 3 The first resistor, the first capacitor, and the second resistor are shown.

[0056] It is understandable that the specific circuit structure of the energy absorption unit 12 is described as a network topology composed of passive linear components. Circuit topology refers to the specific connections and interrelationships between components in a circuit. This topology can be equivalently represented as a network formed by connecting three basic components—a first resistor, a first capacitor, and a second resistor—according to specific rules.

[0057] The first end of the first resistor is connected to the first end of the first capacitor and the second end of the response switch unit 11; the second end of the first resistor is connected to the second end of the first capacitor and the first end of the second resistor; and the second end of the second resistor is connected to the second end of the protected device.

[0058] Understandably, the function of this circuit topology is to provide a controlled discharge path for the transient inrush current of the rapid inrush when the response switch unit 11 is turned on due to high dv / dt triggering, and to absorb and dissipate energy in the process to suppress overvoltage.

[0059] Specifically, the primary function of the first capacitor is to absorb high-frequency current pulse energy. Since the capacitor's terminal voltage cannot change abruptly, it exhibits low impedance characteristics during the sharp rise of transient voltage, enabling it to quickly receive charge and effectively slow down the voltage rise rate (dv / dt) and smooth out voltage spikes. The first resistor is connected in parallel with the first capacitor; its function is to provide a discharge path for capacitor C1 and dampen local oscillations that may be caused by LC parasitic parameters, preventing high-frequency resonance between the capacitor and the circuit inductance.

[0060] Understandably, the second resistor is connected in series in the entire RC branch. Its main function is to limit the peak value of the inrush current and to directly convert some of the electromagnetic energy into heat energy for consumption. At the same time, it and the first capacitor also form an additional damping network to further smooth the voltage waveform.

[0061] Specifically, the capacitance value of the first capacitor satisfies the following constraint: ; in, That is the capacitance value of the first capacitor; It is a stray inductance in the circuit; It is the maximum short-circuit current; It is the maximum voltage spike margin.

[0062] As can be understood, its physical meaning is that to limit overvoltage spikes caused by sudden changes in current within a circuit, the required absorption capacitor value must be greater than or equal to a minimum value determined by system parasitic parameters and safety margins. The direct purpose of the formula is to guide engineers in rationally selecting capacitor values ​​to ensure that voltage spikes are limited to a safe range under the most severe preset fault conditions. Within.

[0063] In one embodiment, the resistance value of the second resistor satisfies the following constraint: ; in, It is the resistance value of the second resistor; It is a loop capacitor; It is a stray inductance in the circuit; It is the maximum short-circuit current; It is the maximum voltage spike margin.

[0064] Understandably, the physical meaning is to achieve effective overvoltage suppression and energy dissipation in circuits with parasitic inductance and capacitance. The selected second resistor value must simultaneously meet both lower and upper limits. The lower limit ensures that the circuit response is in an overdamped state to suppress oscillations that may be caused by LC resonance; the upper limit ensures that the voltage drop across the resistor does not exceed the safety threshold under the maximum fault current, thereby reliably clamping the voltage.

[0065] Understandably, this RC network-type energy absorption unit 12, in series with the aforementioned dv / dt-triggered reverse blocking double-ended solid-state thyristor, together constitutes a first surge protection module 10. The response switch unit 11, acting as a high-speed switch, ensures the conduction path is completed within nanoseconds; the subsequent RC absorption network utilizes the voltage integral effect of the capacitor and the energy dissipation effect of the resistor to smooth, limit, and dissipate the large current flowing through the steep voltage surge, thereby limiting the residual voltage to a safe level. This combination utilizes simple passive linear components to achieve a reliable, low-cost, and polarity-independent overvoltage energy absorption scheme, particularly suitable for protection scenarios requiring smoothing of rapid voltage transients.

[0066] In addition, the second surge protection module 20 includes: a metal oxide surge arrester; a first end of the metal oxide surge arrester is connected to a first end of the protected device; and a second end of the metal oxide surge arrester is connected to a second end of the protected device.

[0067] Understandably, in this embodiment, the second surge protection module 20, through parallel connection of a metal oxide surge arrester, provides a backup protection layer for the system with high energy absorption. It complements the aforementioned first surge protection module based on dv / dt triggering and RC absorption, providing active and rapid peak clipping: the first module precisely and rapidly suppresses ultra-fast voltage spikes in the nanosecond to microsecond range; the second surge protection module, as a subsequent energy discharge channel, is responsible for absorbing and limiting overvoltages with longer durations and greater energy. Working together, they constitute a comprehensive, hierarchical, and coordinated overvoltage protection system covering the entire waveform.

[0068] In summary, the second aspect of this application relates to a circuit breaker, please refer to... Figure 3 It includes: the protected device and the peak-shaving surge arrester of the first aspect; the peak-shaving surge arrester is connected in parallel with the protected device and is connected in series in the working circuit as a whole.

[0069] It should be noted that both mechanical switches and power electronic switches are protected components. Mechanical switches are subject to the risk of arc reignition, while power electronic switches are subject to the risk of breakdown.

[0070] Understandably, this connection ensures that the surge arrester is always connected in parallel with the protected device, providing it with continuous overvoltage protection, regardless of whether the switch is in the open or closed state.

[0071] Compared to traditional surge arresters that only include a second surge protection module, this application verifies the peak-shaving effect of introducing the first module through simulation. Verification was conducted at a 6kV voltage level using four equivalent RBDTs. Please refer to the simulation results. Figure 4 , Figure 4 This is a comparison chart of peak reduction effects at a 6kV voltage level provided in the embodiments of this application.

[0072] Understandable Figure 4 The peak-shaving effect comparison graph shown intuitively verifies the significant performance improvement brought about by the introduction of the first surge arrester module, fast dv / dt triggering, and RC absorption module. The horizontal axis of the graph represents time, and the vertical axis represents the voltage across the protected device. It compares the voltage waveforms of the original situation with only the second surge arrester module, i.e., the metal oxide surge arrester, and the voltage waveforms after adopting the complete peak-shaving surge arrester of this application.

[0073] It should be noted that, as shown by the green curve in the waveform diagram, in the traditional scheme, at the critical moment when the switch disconnects the inductive load and causes current transfer (around 1.00 ms), the voltage across the protected device rises sharply by about 6.5 kV. Due to the inherent response characteristics of the metal oxide surge arrester (MOV) and the influence of its stray inductance, its operation has a slight delay, resulting in an extremely high voltage spike before reaching its conduction threshold, i.e., the overshoot in the original case shown in the diagram. Subsequently, the MOV operates and clamps the voltage to its residual voltage level, but this initial spike already poses a threat to the insulation, and the subsequent residual voltage value is also relatively high.

[0074] It should be noted that the improvement effect of the proposed solution is shown as the main black curve in the waveform diagram. After the introduction of the first lightning protection module, the voltage waveform is significantly optimized.

[0075] Understandably, under the action of the first surge protection module, in the very early stages of the rapid voltage rise, response switching units based on high dv / dt triggering, such as RBDTs (if the withstand voltage is 2 kV, four RBDTs are needed here), quickly conduct, guiding the surge current into the RC absorption network. The voltage of the first capacitor cannot change abruptly, forcibly limiting the voltage rise rate, thereby effectively suppressing the voltage peak to a significantly lower level at approximately 1.005 ms (the residual voltage point of the MOV shown in the figure, approximately 5.8 kV), completely eliminating the dangerous spike in the original situation.

[0076] Furthermore, the system voltage level was adjusted to 10kV, using 5 RBDTs (circuit diagram omitted here). Simulation results are as follows: Figure 5 As shown, Figure 5 This is a comparison chart of peak reduction effects at a 10kV voltage level provided in the embodiments of this application.

[0077] Understandably, the simulation waveforms clearly reveal the differences between the two schemes. At the critical moment of current transfer, the above figure still shows obvious shortcomings: due to the inherent response delay of the metal oxide surge arrester (MOV) and the influence of stray inductance in the loop, the voltage across the protected device rises rapidly, forming an extremely high overshoot spike, whose peak value far exceeds the 10kV safety threshold. Figure 5 The peaks are basically consistent before being clamped to a higher residual pressure level.

[0078] In contrast, the proposed solution, as shown in the figure below, exhibits superior dynamic protection performance. Thanks to the high-sensitivity dv / dt triggering mechanism of the first module composed of five RBDTs, the switching unit quickly turns on in the initial stage when the voltage begins to rise sharply, forcibly directing the transient surge current into the RC absorption network. Utilizing the physical characteristic that the voltage across a capacitor cannot change abruptly, the voltage rise rate is greatly suppressed. Ultimately, the voltage waveform is smoothly raised and limited to a level below 10kV, not only completely eliminating dangerous voltage spikes but also slightly reducing the final clamping voltage compared to traditional solutions. This fully demonstrates that this topology also possesses strong adaptability and excellent protection performance in 10kV systems.

[0079] Furthermore, regarding Figure 5 The upper and middle figures were subjected to Fourier decomposition, and the results are as follows: Figure 6 and Figure 7 As shown, Figure 6 This application provides a Fourier decomposition spectrum diagram of a 10kV voltage level surge arrester using only metal oxide surge arresters; Figure 7 This application provides a Fourier decomposition power spectral density diagram of a 10kV voltage level surge arrester using only metal oxide surge arresters.

[0080] Depend on Figure 6 As can be seen, the frequency axis of the original waveform extends to 116,000 Hz, and it has a long, incompletely decaying oscillation tail throughout the high-frequency range. This indicates that the traditional commutation instant generates highly destructive high-frequency harmonics.

[0081] In addition, by Figure 7 As can be seen, the sidelobes before the improvement were very dense, and the power amplitude was still around 10 in the high-frequency region of tens of thousands of hertz. 2 The fact that the energy level hovers around the same level indicates that the transient energy in the system is oscillating repeatedly and cannot be dissipated quickly.

[0082] Furthermore, regarding Figure 5 The lower part of the graph is subjected to Fourier decomposition, and the result is as follows: Figure 8 and Figure 9 As shown, Figure 8 This is a Fourier decomposition spectrum of an improved surge arrester with a voltage level of 10kV provided in an embodiment of this application; Figure 9 This is a Fourier decomposition power spectral density diagram of an improved surge arrester with a voltage level of 10kV provided in an embodiment of this application.

[0083] Depend on Figure 8As can be seen, after introducing the peak-shaving branch, the frequency axis of the spectrum shrinks directly to 16800 Hz, which means that the high-frequency components above 16.8 kHz are completely smoothed out. This perfectly confirms the high-frequency bypass function of the RBDT branch. The RBDT conducts rapidly at extremely high dv / dt, providing an extremely low impedance path for high-frequency transient currents, and cleanly eliminating the high-frequency energy that causes overshoot.

[0084] In addition, by Figure 9 As can be seen, the number of sidelobes is significantly reduced after the improvement, and the energy converges rapidly at 16.8 kHz. This proves that the series damping resistor Rs plays a crucial role in dissipation. After the high-frequency transient energy is introduced into the branch by the RBDT, it is not bounced back to the main circuit, but is actually converted into heat energy and dissipated by the resistor.

[0085] Spectrum analysis results show that, after introducing the RBDT composite absorption branch described in this invention, the high-frequency harmonic components of the transient voltage interrupted by the circuit breaker are deeply suppressed. Its significant high-frequency characteristic bandwidth drops sharply from the 100 kHz level to below 20 kHz, and the high-frequency sidelobe energy achieves rapid convergence and dissipation. This frequency domain characteristic fundamentally eliminates the transient overshoot voltage excited by the coupling of high-frequency harmonics and stray inductance, verifying that this scheme greatly improves the electromagnetic transient operating environment of fully controllable semiconductor devices without changing the steady-state characteristics of the system.

[0086] Understandably, this application breaks through the limitation of traditional hybrid DC circuit breakers relying solely on a single metal oxide surge arrester (MOV) for overvoltage protection. It innovatively introduces a composite absorption branch, consisting of a reverse blocking double-ended solid-state thyristor (RBDT) connected in parallel across the circuit breaker (both ends of the MOV), and a damping element. This topology is simplified and requires no additional complex power supply or control circuits, providing a dedicated, extremely low-impedance bypass path for high-frequency transient commutation currents from a hardware architecture perspective.

[0087] Understandably, traditional solutions require a single MOV to have both extremely fast response to suppress high-frequency spikes and extremely large capacity to absorb DC energy, which presents a difficult-to-overcome contradiction in terms of physical materials science. This application achieves the physical separation and decoupling of transient and steady-state protection. In the nanosecond-level transient phase at the beginning of commutation, the RBDT branch conducts extremely quickly, cleanly and efficiently smoothing out the fatal voltage spikes caused by stray inductance. In the subsequent millisecond-level steady-state phase, the RBDT branch is limited by damping components and withdraws from dominance, and the system short-circuit current smoothly transfers to the MOV, which performs residual voltage clamping and energy absorption according to its inherent nonlinear VI curve. The two functions perform their respective roles without interference.

[0088] Understandably, this application fundamentally eliminates system-level catastrophic risks such as dynamic avalanche breakdown of fully controlled devices (e.g., IGBTs) in transfer branches caused by transient overvoltage spikes, and arc reignition at the mechanical switching (UFD) break points. This allows the overall insulation coordination design of the circuit breaker to directly match the static residual voltage of the MOV, eliminating the need to blindly increase the number of expensive semiconductor device series stages and the mechanical switching travel to prevent uncontrollable transient spikes. This not only greatly improves the breaking reliability of the equipment but also results in a significant reduction in the manufacturing cost and size of a single high-voltage DC unit.

[0089] It should be understood that expressions such as “comprising” and “may include” used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as “comprising” and / or “having” are to be interpreted as indicating a particular characteristic, number, operation, constituent element, component, or combination thereof, but not to exclude the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0090] Furthermore, in this application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" may include A, may include B, or may include both A and B.

[0091] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A peak shaving arrester, characterized in that include: First lightning protection module and second lightning protection module; The first end of the first lightning protection module is connected to the first end of the second lightning protection module and the first end of the protected device, respectively; the second end of the first lightning protection module is connected to the second end of the second lightning protection module and the second end of the protected device, respectively. The first lightning protection module is configured to conduct the discharge channel in response to a port voltage change rate greater than a preset threshold, so as to suppress transient overvoltage; The second lightning protection module is configured to absorb energy after transient overvoltage is suppressed.

2. The peak shaving arrester of claim 1, wherein, The first lightning protection module includes: a response switch unit and an energy absorption unit; The first end of the response switch unit is connected to the first end of the protected device; the second end of the response switch unit is connected to the first end of the energy absorption unit; the second end of the energy absorption unit is connected to the second end of the protected device to form a discharge channel. The response switch unit is configured to turn on the discharge channel in response to a port voltage change rate greater than a preset threshold. The energy absorption unit is configured to absorb energy to suppress transient overvoltage when the discharge channel is turned on.

3. The peak shaving arrester of claim 2, wherein, The response switch unit includes: multiple reverse blocking double-ended solid-state thyristors; The anode and cathode of the plurality of reverse blocking double-ended solid thyristors are connected in series from end to end, with the first end of the series connection connected to the first end of the protected device and the last end of the series connection connected to the first end of the energy absorption unit.

4. The surge arrester as described in claim 3, characterized in that, The number of reverse blocking dual-ended solid thyristors is determined based on the port voltage threshold of the first lightning protection module.

5. The peak clipper lightning arrestor of claim 3, wherein, The application scenario of the peak-shaving surge arrester is determined by the conduction threshold of the reverse blocking double-ended solid thyristor.

6. The peak clipper lightning arrestor of claim 2, wherein, The energy absorption unit includes: a first resistor, a first capacitor, and a second resistor; The first end of the first resistor is connected to the first end of the first capacitor and the second end of the response switch unit; the second end of the first resistor is connected to the second end of the first capacitor and the first end of the second resistor; the second end of the second resistor is connected to the second end of the protected device.

7. The peak clipper lightning arrestor of claim 5, wherein, The capacitance value of the first capacitor satisfies the following constraint: ； wherein, is a capacitance value of the first capacitor; is a loop inductance; is a maximum short circuit current; is a maximum voltage spike margin.

8. The peak clipper lightning arrestor of claim 5, wherein, The resistance value of the second resistor satisfies the following constraint: ； wherein, is the resistance value of the second resistor; is the loop capacitance; is the loop stray inductance; is the maximum short circuit current; is the maximum voltage spike margin.

9. The peak clipper lightning arrestor of claim 1, wherein, The second lightning protection module includes: a metal oxide surge arrester; The first end of the metal oxide surge arrester is connected to the first end of the protected device; the second end of the metal oxide surge arrester is connected to the second end of the protected device.

10. A circuit breaker, characterized in that, include: The protected device and the surge arrester as described in any one of claims 1 to 9; The surge arrester is connected in parallel with the protected device, and then the whole system is connected in series in the working circuit.

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