Generator outlet breaker

Abstract

A generator outlet breaker comprises a main current branch, a current-limiting transfer branch, a freewheeling branch and a fast switch; the main current branch comprises high-speed mechanical switches S1 and S2 connected in parallel, and the two ends of the high-speed mechanical switches S1 and S2 are directly connected with the outlet ends of the breaker; one end of the current-limiting transfer branch is connected in parallel with one end of the main current branch, and the other end is connected with the other end of the main current branch through the fast switch S3, wherein the current-limiting transfer branch comprises a transfer capacitor C, an inductor L, thyristor assemblies T1 and T2 and a current-limiting resistor R; the freewheeling branch is connected in parallel with the two ends of the main current branch and the current-limiting transfer branch, and the freewheeling branch comprises thyristor assemblies T3 and T4. The present application realizes the rapid limitation and breaking of the short-circuit current of the generator outlet, has the advantages of fast breaking speed, strong current suppression capability, large breaking capacity and the like, and can meet the operation requirements of large-scale power generation systems.

Description

Technical Field

[0001] This invention relates to the field of circuit breakers, and in particular to a generator outlet circuit breaker. Background Technology

[0002] In large power plants, generator circuit breakers are core equipment ensuring the safe and reliable operation of the system. Traditional generator outlet circuit breakers mainly rely on SF6 or vacuum media for arc extinguishing and interruption, which suffers from slow response speed, long operating time, and insufficient breaking capacity, making it difficult to meet the fault protection requirements of future megawatt-class and above generator units. To address the shortcomings of the above-mentioned interruption schemes, this invention proposes a high-capacity, fast generator outlet circuit breaker based on current transfer suppression. It aims to achieve rapid current limiting and interruption of generator outlet short-circuit current by combining forced current transfer current limiting with high-speed mechanical switching. It has advantages such as fast interruption speed, strong current suppression capability, and large breaking capacity, and can meet the operational requirements of large-scale power generation systems.

[0003] The information disclosed in the background section is only intended to enhance the understanding of the background of the present invention, and therefore may contain information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] To address the shortcomings or defects of the existing technology, a generator outlet circuit breaker is provided. By controlling the operation of a high-speed mechanical switch, and then triggering the transfer and current-limiting branches according to a specific timing sequence, the current is rapidly transferred and current is limited. Finally, the circuit breaker is disconnected at the zero-crossing point, thereby achieving rapid limitation of generator outlet short-circuit faults. It also has the function of interrupting currents in different directions.

[0005] The objective of this invention is achieved through the following technical solutions.

[0006] A generator outlet circuit breaker includes:

[0007] Main current branch, current limiting transfer branch, freewheeling branch and fast switch;

[0008] The main current branch includes a high-speed mechanical switch S1 and a high-speed mechanical switch S2 connected in parallel. The two ends of the high-speed mechanical switch S1 and the high-speed mechanical switch S2 are directly connected to the output terminals of the circuit breaker, respectively.

[0009] One end of the current limiting transfer branch is connected in parallel to one end of the main current branch, and the other end is connected to the other end of the main current branch via a fast switch S3. The current limiting transfer branch includes a transfer capacitor C, an inductor L, thyristor assemblies T1 and T2, and a current limiting resistor R.

[0010] The freewheeling branch is connected in parallel across the main current branch and the current limiting transfer branch. The freewheeling branch includes thyristor assemblies T3 and T4.

[0011] In the generator outlet circuit breaker, in the current-limiting transfer branch;

[0012] The transfer capacitor C, inductor L, and thyristor assemblies T1 and T2 are connected in series, then in parallel with current limiting resistor R, and then in series with fast switch S3.

[0013] In the generator outlet circuit breaker, under normal system current conditions, the system current flows through the main current branch, and the high-speed mechanical switch S1 and high-speed mechanical switch S2 bear the rated current.

[0014] In the aforementioned generator outlet circuit breaker, when the forward short-circuit current is interrupted, the control system simultaneously issues a tripping operation command to the high-speed mechanical switches S1 and S2.

[0015] In the generator outlet circuit breaker, when the high-speed mechanical switches S1 and S2 open a certain distance in 2-5ms, the thyristor assembly T1 and the thyristor assembly T3 are triggered to conduct.

[0016] The current begins to transfer to the current-limiting transfer branch and freewheels through the thyristor assembly T3. When the freewheeling current crosses zero, the current enters the current-limiting branch as the capacitor voltage rises, and the fault current is limited. When the current is limited, the control system sends a tripping command to the fast switch S3. After the current in S3 crosses zero, the arc is extinguished, completing the short-circuit current limiting interruption.

[0017] In the generator outlet circuit breaker, under reverse breaking conditions, T1 is triggered first, the LC branch first undergoes a current oscillation, the capacitor voltage reverses, and T1 is cut off when the current crosses zero; then, the control system sends a tripping action command to the high-speed switches S1 and S2 simultaneously. When S1 and S2 open a certain distance in 2-5ms, T2 and T4 are triggered to conduct.

[0018] The current is transferred to the LC branch and freewheels through the thyristor T4. When the freewheeling current crosses zero, the current enters the current limiting branch as the capacitor voltage rises, and the fault current is limited. When the current is limited, the control system sends a trip command to the fast switch S3. After the current in S3 crosses zero, the arc is extinguished, and the short-circuit current limiting interruption is completed.

[0019] In the generator outlet circuit breaker, the high-speed mechanical switches S1 and S2 are vacuum switches based on electromagnetic repulsion. When the rated current and short-circuit current increase, the number of high-speed mechanical switches connected in parallel can be increased according to the current demand.

[0020] In the aforementioned generator outlet circuit breaker, the fast switch S3 is a vacuum fast switch.

[0021] In the generator outlet circuit breaker, the transfer capacitor C includes any one or a combination of multiple of the following: film capacitor, organic dielectric capacitor, inorganic dielectric capacitor, electrolytic capacitor, electrothermal capacitor, and air dielectric capacitor.

[0022] The connection method and control timing of the circuit elements in this invention are designed for interrupting large AC currents with high peak short-circuit currents and high DC components at the generator outlet. The magnitude of the short-circuit current varies depending on the system; in large-capacity systems, the peak short-circuit current can reach over 575kA, and the asymmetry coefficient representing the DC component can be greater than 130%. This invention enables rapid interruption after rapid current limiting, significantly reducing the strain on the arc-extinguishing chamber's arcing time and energy, and greatly improving the ability to interrupt large currents. For large current interruption where a single arc-extinguishing chamber is insufficient, the main current branch employs multiple fast switches connected in parallel. These parallel fast switches operate synchronously, achieving rapid limiting and interruption of the generator outlet short-circuit current. This method offers advantages such as fast interruption speed, strong current suppression capability, and large interruption capacity, meeting the operational requirements of large-scale power generation systems.

[0023] The above description is merely an overview of the technical solution of the present invention. In order to make the technical means of the present invention clearer and more understandable, so that those skilled in the art can implement it according to the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more obvious and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0024] Various other advantages and benefits of the present invention will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0025] In the attached diagram:

[0026] Figure 1 This is a schematic diagram of the bidirectional interruption topology of a generator outlet circuit breaker according to an embodiment of the present invention;

[0027] Figures 2(a) to 2(h) A schematic diagram of the operation of a generator outlet circuit breaker when interrupting a forward short-circuit current according to an embodiment of the present invention;

[0028] Figure 3 A waveform diagram of a generator outlet circuit breaker interrupting a forward short-circuit current according to an embodiment of the present invention;

[0029] Figures 4(a) to 4(k) A schematic diagram of the operation of a generator outlet circuit breaker when interrupting reverse short-circuit current according to an embodiment of the present invention;

[0030] Figure 5 A waveform diagram of the generator outlet circuit breaker interrupting the reverse short-circuit current according to an embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram of the delayed zero-crossing current waveform when the DC component is very high after a short-circuit current occurs in the system.

[0032] Figure 7 This is a schematic diagram of a 210kA short-circuit current breaking test according to an embodiment of the present invention.

[0033] The present invention will be further explained below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0034] The following will refer to the appendix. Figures 1 to 7 Specific embodiments of the invention will be described in more detail below. While specific embodiments of the invention are shown in the accompanying drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0035] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions are preferred embodiments for carrying out the invention; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of the invention. The scope of protection of this invention is determined by the appended claims.

[0036] To facilitate understanding of the embodiments of the present invention, the following will provide further explanation and description with reference to the accompanying drawings and several specific embodiments, and the accompanying drawings do not constitute a limitation on the embodiments of the present invention.

[0037] like Figures 1 to 7As shown, a generator output circuit breaker includes a main current branch, a current-limiting transfer branch, a freewheeling branch, and a fast switch. The main current branch includes a high-speed mechanical switch S1 and a high-speed mechanical switch S2 connected in parallel, with the two ends of the high-speed mechanical switches S1 and S2 directly connected to the output terminals of the circuit breaker. The two ends of the current-limiting transfer branch are connected in parallel to the two ends of the main current branch. The transfer capacitor C, the inductor L, and the thyristor assemblies T1 and T2 are connected in series, and then connected in parallel with the current-limiting resistor R. The freewheeling branch is connected in parallel to the main current branch and the current-limiting transfer branch. The freewheeling branch includes thyristor assemblies T3 and T4. The fast switch S3 is located between the current-limiting transfer branch and the main current branch.

[0038] In a preferred embodiment of the generator outlet circuit breaker, under normal system current conditions, the system current flows through the main current branch, and the high-speed mechanical switch S1 and the high-speed mechanical switch S2 bear the rated current.

[0039] When the forward short-circuit current is interrupted, the control system simultaneously sends a tripping command to high-speed mechanical switches S1 and S2. After high-speed mechanical switches S1 and S2 open by a certain distance within 2-5ms, thyristor assemblies T1 and T3 are triggered to conduct.

[0040] The current begins to transfer to the current-limiting transfer branch. After the current in S1 and S2 of the main branch crosses zero, the transfer current will freewheel through the thyristor assembly T3. After the freewheeling current crosses zero, as the capacitor voltage rises, the current enters the current-limiting branch. The fault current is limited by the current-limiting resistor R. When the current is limited, the amplitude of the short-circuit current decreases, and the DC component decays rapidly. The control system sends a trip command to the fast switch S3. Afterward, the arc is extinguished after the current in S3 crosses zero, completing the short-circuit current limiting and breaking.

[0041] The value of the current-limiting resistor R is selected based on the rated voltage of the system, so that the short-circuit current after current limiting is less than or equal to the rated short-circuit breaking current of conventional medium and high voltage vacuum circuit breakers, such as 31.5kA, 40kA, 50kA, 63kA, etc. However, the cost and size will increase if the selected current is larger; taking 31.5kA as an example, the current-limiting resistor R can be selected as 1-3 ohms.

[0042] In the preferred embodiment of the generator outlet circuit breaker, under reverse interruption conditions, T1 is first triggered, and the transfer branch capacitor C discharges once. The current passes through the thyristor T1 and the main branches S1 and S2 to complete a half-wave current oscillation, causing the capacitor voltage to reverse. When the oscillation current crosses zero, T1 is cut off. After that, the control system sends a tripping action command to the high-speed switches S1 and S2 simultaneously. When S1 and S2 open a certain gap in 2-5ms, T2 and T4 are triggered to conduct.

[0043] The current begins to transfer to the current-limiting transfer branch. After the current in S1 and S2 of the main branch crosses zero, the transfer current will freewheel through thyristor T4. After the freewheeling current crosses zero, as the capacitor voltage increases, the current enters the current-limiting branch. The fault current is limited by the current-limiting resistor R. When the current is limited, the amplitude of the short-circuit current decreases, and the DC component decays rapidly. The control system sends a trip command to the fast switch S3. Afterward, the arc is extinguished after the current in S3 crosses zero, completing the short-circuit current limiting and breaking.

[0044] In a preferred embodiment of the generator outlet circuit breaker, the high-speed mechanical switches S1 and S2 are vacuum switches based on an electromagnetic repulsion mechanism. When the rated and short-circuit currents of the circuit breaker are larger, the number of high-speed mechanical switches connected in parallel can be increased.

[0045] In a preferred embodiment of the generator outlet circuit breaker, the fast switch S3 is a vacuum fast switch.

[0046] In a preferred embodiment of the generator outlet circuit breaker, the transfer capacitor C includes any one or a combination of multiple of the following: film capacitor, organic dielectric capacitor, inorganic dielectric capacitor, electrolytic capacitor, electrothermal capacitor, and air dielectric capacitor.

[0047] In a preferred embodiment of the generator outlet circuit breaker, the thyristor assemblies T3 and T4 in the freewheeling branch are composed of two anti-parallel thyristor assemblies. Furthermore, the thyristor assemblies T1 and T2 in the current-limiting transfer branch are composed of two anti-parallel thyristor assemblies.

[0048] Figures 2(a) to 2(h) The process of a circuit breaker interrupting a short-circuit current when the short-circuit current is in the positive direction is given:

[0049] (1) As shown in Figure 2(a), under normal current conditions, the system current flows in from the output terminal A1, and flows out from the output terminal A2 after passing through the parallel high-speed mechanical switch.

[0050] (2) As shown in Figure 2(b), when the detection system detects a positive short circuit fault in the system, the short circuit current of the system is i1 and the main branch current is i3. The detection system notifies the control system to issue a tripping command, and the high-speed mechanical switches S1 and S2 open at the same time to start arcing.

[0051] (3) As shown in Figure 2(c), when the high-speed mechanical switches S1 and S2 are opened by a certain gap, the thyristors T1 and T3 are triggered to conduct, and the capacitor C begins to discharge through T1 and the main branch S1 and S2 to form a transfer current. As the transfer current i2 increases, the main branch current i3 decreases.

[0052] (4) As shown in Figure 2(d), as the transfer current i2 increases, when the amplitude of i2 exceeds the system current i1, the transfer current exceeding i1 will be freewheeled through T3, and the freewheeling current is i4.

[0053] (5) As shown in Figure 2(e), after the transfer current i2 reaches its peak value, it begins to decrease. When i2 is less than the system current i1, the freewheeling current i4 crosses zero and T3 is cut off. The current enters the current limiting resistor R, which is represented by i5.

[0054] (6) As shown in Figure 2(f), since the impedance of resistor R is much smaller than the impedance of the current-limiting branch LC, the subsequent system current i1 basically enters the branch of resistor R, the current begins to be significantly limited, and the DC component rapidly decays to 0.

[0055] (7) As shown in Figure 2(g), after the current begins to be significantly limited, the control system triggers S3 to disconnect, and S3 begins to ignite the arc.

[0056] (8) As shown in Figure 2(h), when the AC current after current limiting naturally crosses zero, S3 extinguishes the arc and completes the short-circuit current interruption.

[0057] Figure 3 The waveform diagrams of the circuit breaker interrupting the forward short-circuit current are given. Among them, curve i1 is the total system current, curve i2 is the LC branch transfer current, curve i3 is the main current branch current, i.e., the breaking current, curve i4 is the freewheeling current, and curve i5 is the current limiting branch current.

[0058] In fact, the generator circuit breaker interrupts alternating current, which can be in both forward and reverse directions. The following diagram illustrates the process of the circuit breaker interrupting the reverse short-circuit current:

[0059] (1) As shown in Figure 4(a), under normal current conditions, the system current flows in from the output terminal A2, and flows out from the output terminal A1 after passing through the parallel high-speed mechanical switch.

[0060] (2) As shown in Figure 4(b), when the detection system detects a reverse short circuit fault in the system, the short circuit current of the system is i1 and the main branch current is i3. The detection system notifies the control system to issue a command to turn on T1. The pre-charged capacitor C is negative on the left and positive on the right. The capacitor begins to discharge through T1 and the closed main branches S1 and S2 to form an oscillating current.

[0061] (3) As shown in Figure 4(c), after the oscillating current reaches its peak, the voltage of capacitor C begins to reverse and becomes positive on the left and negative on the right.

[0062] (4) As shown in Figure 4(d), when the oscillating current crosses zero, the thyristor T1 is cut off, the voltage of capacitor C is reversed, and the short-circuit current exists entirely in the main branches S1 and S2.

[0063] (5) The subsequent action process is similar to the forward process disconnection, as shown in Figure 4(e). The system short circuit current is i1, the main branch current is i3, the control system issues a trip command, and the high-speed mechanical switches S1 and S2 open at the same time to start arcing.

[0064] (6) As shown in Figure 4(f), when the high-speed mechanical switches S1 and S2 are opened by a certain gap, the thyristors T2 and T4 are triggered to conduct. The capacitor C begins to discharge through T2 and the main branch S1 and S2 to form a transfer current. As the transfer current i2 increases, the main branch current i3 decreases.

[0065] (7) As shown in Figure 4(g), as the transfer current i2 increases, when the amplitude of i2 exceeds the system current i1, the transfer current exceeding i1 will be freewheeled through T4, and the freewheeling current is i4.

[0066] (8) As shown in Figure 4(h), after the transfer current i2 reaches its peak value, it begins to decrease. When i2 is less than the system current i1, the freewheeling current i4 crosses zero and T4 is cut off. The current enters the current limiting resistor R, which is represented by i5.

[0067] (9) As shown in Figure 4(i), since the impedance of resistor R is much smaller than the impedance of current-limiting branch LC, the subsequent system current i1 basically enters the branch of resistor R, the current begins to be significantly limited, and the DC component rapidly decays to 0.

[0068] (10) As shown in Figure 4(j), after the current starts to be significantly limited, the control system triggers S3 to disconnect, and S3 starts to ignite the arc.

[0069] (11) As shown in Figure 4(k), S3 extinguishes the arc after the AC current after current limiting naturally crosses zero, thus completing the short-circuit current interruption.

[0070] Figure 5 The waveform diagram of the reverse short-circuit current interrupted by the circuit breaker is given. Among them, curve i1 is the total system current, curve i2 is the LC branch transfer current, curve i3 is the main current branch current, i.e., the interrupt current, curve i4 is the freewheeling current, and curve i5 is the current limiting branch current.

[0071] The short-circuit current at the outlet of large nuclear power, hydropower, and thermal power generators is particularly large, with an effective value exceeding 210kA and a peak value exceeding 575kA. Simultaneously, the DC component is exceptionally large, and the asymmetry can exceed 130%, leading to delayed zero-crossing. For example... Figure 6As shown, the international market for circuit breakers with a short-circuit breaking capacity exceeding 210kA is almost entirely monopolized by the Swiss company ABB, making it a bottleneck technology for my country. ABB uses the arc-extinguishing scheme of SF6 circuit breakers, in which its technology is the most advanced. Its breaking principle involves a hydraulic spring mechanism driving the contacts to open, utilizing the SF6 gas blowing effect formed by the nozzle of the arc-extinguishing chamber to achieve arc extinguishing at the current zero-crossing point. Because SF6 AC circuit breakers rely on the natural zero-crossing point of the short-circuit current, they need to wait for the DC component to decay and form a zero-crossing point during breaking, resulting in a long zero-crossing breaking time. The duration of the huge short-circuit current can exceed 60ms, posing a greater risk of short-circuit current surges to the system. Simultaneously, the long travel of the SF6 circuit breaker mechanism leads to a long arc burning time and extremely high arc energy within the arc-extinguishing chamber, exceeding 25ms, making it difficult to improve breaking capacity and resulting in a low short-circuit breaking life. Furthermore, the use of SF6 gas as the arc-extinguishing medium in SF6 circuit breakers is not environmentally friendly and does not conform to the trend of environmentally friendly development of power equipment in my country. This invention employs a different technical approach, utilizing a high-speed mechanical switch combined with a vacuum interrupter as the main circuit break. Addressing the issue of insufficient capacity of a single vacuum interrupter for high-current breaking, the main current branch uses multiple high-speed vacuum switches connected in parallel, allowing them to operate synchronously and solving the problem of the single vacuum interrupter's capacity to withstand high currents. More importantly, the high-speed vacuum switches have short travel and high speed. Combined with current transfer and current limiting effects, they can break the main circuit current at zero crossing when the current is at its lowest point after the first large current peak following a short circuit. After the current transfer, resistor R is used to achieve short-circuit current limiting. On one hand, the sudden change in resistance rapidly decays the DC component of the short circuit to zero; on the other hand, the short-circuit current becomes the rated current level. Then, the fast switch S3 in the transfer branch easily completes the short-circuit fault breaking. Therefore, this invention has a faster breaking speed, allowing the duration of a huge short-circuit current in the system to be less than 20ms, and the arcing time at the main break is very short, less than 5ms. This is highly advantageous for breaking such huge short-circuit currents and significantly reduces the impact of large currents on the system. The prototype based on this invention has passed a 210kA short-circuit current breaking test at the Xi'an High Voltage Electrical Apparatus Research Institute. Figure 7 As shown, the short-circuit current begins to occur at 20ms, with an effective value of 210kA. Due to the superposition of the DC component, the peak value of the short-circuit current reaches 576kA. Using the interruption method of the present invention, the interruption of the huge short-circuit current is achieved before 40ms.

[0072] Although embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments and application fields described above. The specific embodiments described above are merely illustrative and instructive, and not restrictive. Those skilled in the art can make many other forms based on the guidance of this specification and without departing from the scope of protection of the claims of the present invention, and all of these are within the scope of protection of the present invention.

Claims

1. A generator outlet circuit breaker, characterized in that, It includes: Main current branch, current limiting transfer branch, freewheeling branch and fast switch; The main current branch includes a high-speed mechanical switch S1 and a high-speed mechanical switch S2 connected in parallel. The two ends of the high-speed mechanical switch S1 and the high-speed mechanical switch S2 are directly connected to the output terminals of the circuit breaker, respectively. One end of the current limiting transfer branch is connected in parallel to one end of the main current branch, and the other end is connected to the other end of the main current branch via a fast switch S3. The current limiting transfer branch includes a transfer capacitor C, an inductor L, a thyristor assembly T1, a thyristor assembly T2, and a current limiting resistor R. The freewheeling branch is connected in parallel across the main current branch and the current limiting transfer branch. The freewheeling branch includes thyristor assembly T3 and thyristor assembly T4. In the aforementioned current-limiting transfer branch; The transfer capacitor C, inductor L are connected in series with thyristor assembly T1 and thyristor assembly T2, then in parallel with current limiting resistor R, and then in series with fast switch S3. Under normal current-carrying conditions, the system current flows through the main current branch, and the high-speed mechanical switch S1 and the high-speed mechanical switch S2 bear the rated current. When the forward short-circuit current is interrupted, the control system simultaneously sends a tripping action command to the high-speed mechanical switches S1 and S2. When the high-speed mechanical switches S1 and S2 open a certain gap in 2-5ms, the thyristor assembly T1 and the thyristor assembly T3 are triggered to conduct. The current begins to transfer to the current-limiting transfer branch and freewheels through the thyristor assembly T3. When the freewheeling current crosses zero, the current enters the current-limiting branch as the capacitor voltage rises, and the fault current is limited. When the current is limited, the control system sends a tripping command to the fast switch S3. After the current in S3 crosses zero, the arc is extinguished, and the short-circuit current limiting interruption is completed. Under reverse interruption conditions, T1 is triggered first, the LC branch first undergoes a current oscillation, the capacitor voltage reverses, and T1 is cut off when the current crosses zero; then, the control system sends a tripping action command to the high-speed switches S1 and S2 simultaneously. After S1 and S2 open a gap in 2-5ms, T2 and T4 are triggered to conduct. The current is transferred to the LC branch and freewheels through the thyristor T4. When the freewheeling current crosses zero, the current enters the current limiting branch as the capacitor voltage rises, and the fault current is limited. When the current is limited, the control system sends a trip command to the fast switch S3. After the current in S3 crosses zero, the arc is extinguished, and the short-circuit current limiting interruption is completed.

2. The generator outlet circuit breaker according to claim 1, characterized in that: The high-speed mechanical switches S1 and S2 are vacuum switches based on electromagnetic repulsion mechanisms; as the rated current and short-circuit current increase, the number of high-speed mechanical switches connected in parallel is increased according to the current demand.

3. The generator outlet circuit breaker according to claim 1, characterized in that: The fast switch S3 is a vacuum fast switch.

4. The generator outlet circuit breaker according to claim 1, characterized in that: The transfer capacitor C includes any one or a combination of organic dielectric capacitors, inorganic dielectric capacitors, electrolytic capacitors, and air dielectric capacitors.

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