Current-limited bidirectional fast circuit breaker
By designing a current-limiting bidirectional fast circuit breaker, and utilizing the coordinated operation of power electronic switches and mechanical switches, the rise rate and magnitude of short-circuit current are limited, thereby achieving the breaking of rated current and rapid clearing of short-circuit faults. This solves the capacity mismatch problem of existing circuit breakers under large-capacity short-circuit currents.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- XIAN SHENGONG ELECTROMECHANICAL EQUIP CO LTD
- Filing Date
- 2025-08-27
- Publication Date
- 2026-07-24
AI Technical Summary
Existing circuit breakers are unable to promptly disconnect short-circuit faults when faced with large-capacity short-circuit currents, resulting in a mismatch between equipment capacity and system short-circuit capacity, and an inability to safely disconnect fault currents.
The design includes a current-limiting bidirectional fast circuit breaker, comprising a current-carrying branch, a current-limiting branch, a converter branch, a buffer branch, a current-limiting inductor branch, and an energy-dissipating branch. Through the coordinated operation of power electronic switches and mechanical switches, the rise rate and magnitude of the short-circuit current are limited, and energy is dissipated using current-limiting inductors and resistors to achieve fast interruption.
It enables the interruption of rated current and effectively limits the rate of rise and magnitude of fault current during short-circuit faults, thereby improving the breaking capacity of the circuit breaker and solving the problem that the circuit breaker cannot clear short-circuit faults in a timely manner.
Smart Images
Figure CN224555188U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of high voltage and ultra-high voltage DC transmission technology, and in particular to a current-limiting bidirectional fast circuit breaker. Background Technology
[0002] Short-circuit faults are the most common faults in power system operation, seriously jeopardizing the normal operation of the power system. At the same time, the continuous expansion of the power system scale, the commissioning of large-capacity units, and the continuous increase in heavy loads have significantly increased the short-circuit current level of the system. With the increase in system short-circuit capacity, the capacity of circuit breakers, disconnectors, and other equipment installed in the system becomes mismatched with the system's short-circuit capacity, to the point that circuit breakers cannot safely interrupt the fault current and clear the short-circuit fault when a short circuit occurs.
[0003] In view of this, the present invention is proposed to solve the above-mentioned technical problems. Utility Model Content
[0004] The purpose of this utility model is to provide a current-limiting bidirectional fast circuit breaker to solve the technical problem that the circuit breaker cannot clear short-circuit faults in time due to the excessive rise rate of short-circuit current during the circuit breaker breaking process.
[0005] The technical solution of this utility model is: a current-limiting bidirectional fast circuit breaker, comprising a current-carrying branch, a current-limiting branch, a converter branch, a buffer branch, a current-limiting inductor branch, and an energy-dissipating branch connected in parallel; The current-carrying branch includes a series-connected fast mechanical switch FMS and a power electronic switch assembly S2; The current-limiting branch includes power electronic switching assembly S3, power electronic switching assembly S4, and current-limiting resistor R. CL1 and current limiting resistor R CL2 Power electronic switch assembly S3, current limiting resistor R CL1 and current limiting resistor R CL2 Series connection, current-limiting resistor R CL2 It is connected in parallel with the power electronic switch assembly S4; The commutation branch includes diodes D1-D4 and semiconductor switching device T5; The buffer branch includes a resistor R1 and a capacitor C1 connected in series; The current-limiting inductor branch includes inductor L1, power electronic switch assembly S1 and energy-consuming resistor Rdisspation. Power electronic switch assembly S1 and energy-consuming resistor Rdisspation are connected in series and then in parallel with inductor L1. The energy-consuming branch includes metal oxide surge arresters (MOVs).
[0006] Furthermore, when the current from the DC power supply flows through the inductor L1, the fast mechanical switch FMS, and the power electronic switch assembly S2, a normally conducting branch is formed.
[0007] Furthermore, when a short circuit fault occurs, the power electronic switch assembly S2 is turned off and the power electronic switch assembly S3 is turned on. The power electronic switch assembly S4 is then turned on based on the magnitude and rise rate of the current. At this time, the current in the current-carrying branch is transferred to the current-limiting branch.
[0008] Furthermore, the current is transferred to the current-limiting branch, opening the fast mechanical switch FMS and simultaneously turning on the semiconductor switching device T5 in the commutation branch. At this time, the current is transferred from the fast mechanical switch FMS branch to the commutation branch. After the fast mechanical switch FMS breaks and establishes insulation, the current is transferred to the commutation branch.
[0009] Furthermore, when the fault current is completely transferred to the converter branch, the semiconductor switching device T5 of the converter branch is turned off, an overvoltage is generated at both ends of the branch, the voltage across the metal oxide surge arrester MOV rises, the current in the semiconductor branch gradually transfers to the buffer branch, and the current in the buffer branch rises.
[0010] Furthermore, when the voltage across the metal oxide surge arrester (MOV) reaches the operating voltage, the resistance of the energy dissipation branch decreases rapidly, the buffer branch current quickly transfers to the energy dissipation branch, the energy dissipation branch current rises, and then the metal oxide surge arrester (MOV) in the energy dissipation branch discharges to dissipate energy, while simultaneously triggering the conduction of the power electronic switch assembly S1. The residual magnetic field energy in the inductor L1 is dissipated through the energy dissipation resistor Rdisspation.
[0011] By adopting the above technical solution, this utility model has the following beneficial effects: The current-limiting bidirectional fast circuit breaker provided in this application can interrupt the rated current. At the same time, it uses an external current-limiting inductor to limit the rate of rise of the fault current and a current-limiting resistor to limit the magnitude and rate of rise of the fault current. Different resistor values can be selected for current limiting according to different operating conditions. The switching branch is used to improve the breaking capacity of the semiconductor switching device to interrupt short-circuit faults. This solves the problem that the circuit breaker cannot clear short-circuit faults in time due to the excessive rate of rise of the short-circuit current during the circuit breaker breaking process. Attached Figure Description
[0012] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but do not constitute an undue limitation of the present invention. Obviously, the drawings described below are merely some embodiments; those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings: Figure 1 This is a circuit diagram of the current-limiting bidirectional fast circuit breaker provided in this embodiment of the application; Figure 2 This is a circuit diagram of the current-limiting bidirectional fast circuit breaker provided in this embodiment of the application; Figure 3 This is a circuit diagram of the current-limiting branch of the current-limiting bidirectional fast circuit breaker provided in this embodiment of the application; Figure 4 This is a circuit diagram of the converter branch of the current-limiting bidirectional fast circuit breaker provided in this embodiment of the application; Figure 5 The circuit diagram of the buffer branch of the current-limiting bidirectional fast circuit breaker provided in this embodiment of the application; Figure 6 The circuit diagram of the current-limiting inductor branch of the current-limiting bidirectional fast circuit breaker provided in this embodiment of the application; Figure 7 This is a schematic diagram of the short-circuit breaking process of the current-limiting bidirectional fast circuit breaker provided in this embodiment of the application during forward current turn-off. Figure 8 This is a schematic diagram of the short-circuit breaking process of the current-limiting bidirectional fast circuit breaker provided in this embodiment of the application when the reverse current is turned off.
[0013] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the present invention in any way, but rather to illustrate the concept of the present invention to those skilled in the art by referring to specific embodiments. Detailed Implementation
[0014] The specific embodiments of this utility model will be described in further detail with reference to the accompanying drawings.
[0015] See Figures 1 to 8 As shown, this application provides a current-limiting bidirectional fast circuit breaker, including parallel current-carrying branches, current-limiting branches, converter branches, buffer branches, current-limiting inductor branches, and energy-dissipating branches; The current-carrying branch includes a series-connected fast mechanical switch FMS and a power electronic switch assembly S2; The current-limiting branch includes power electronic switching assembly S3, power electronic switching assembly S4, and current-limiting resistor R. CL1 and current limiting resistor R CL2 Power electronic switch assembly S3, current limiting resistor R CL1 and current limiting resistor R CL2 Series connection, current-limiting resistor R CL2 It is connected in parallel with the power electronic switch assembly S4; The commutation branch includes diodes D1-D4 and semiconductor switching device T5; The buffer branch includes a resistor R1 and a capacitor C1 connected in series; The current-limiting inductor branch includes inductor L1, power electronic switch assembly S1 and energy-consuming resistor Rdisspation. Power electronic switch assembly S1 and energy-consuming resistor Rdisspation are connected in series and then in parallel with inductor L1. The energy-consuming branch includes metal oxide surge arresters (MOVs).
[0016] When the current from the DC power supply flows through the inductor L1, the fast mechanical switch FMS, and the power electronic switch assembly S2, a normally conducting branch is formed.
[0017] When a short circuit fault occurs, the power electronic switch assembly S2 is turned off and the power electronic switch assembly S3 is turned on. The power electronic switch assembly S4 is turned on based on the current magnitude and rise rate. At this time, the current in the current-carrying branch is transferred to the current-limiting branch.
[0018] The current is transferred to the current-limiting branch, the fast mechanical switch FMS is opened, and the semiconductor switching device T5 of the commutation branch is turned on. At this time, the current is transferred from the fast mechanical switch FMS branch to the commutation branch. After the fast mechanical switch FMS breaks and establishes insulation, the current is transferred to the commutation branch.
[0019] When the fault current is completely transferred to the converter branch, the semiconductor switching device T5 of the converter branch is turned off, an overvoltage is generated at both ends of the branch, the voltage across the metal oxide surge arrester MOV rises, the current in the semiconductor branch gradually transfers to the buffer branch, and the current in the buffer branch rises.
[0020] When the voltage across the metal oxide surge arrester (MOV) reaches the operating voltage, the resistance of the energy dissipation branch decreases rapidly, the buffer branch current quickly transfers to the energy dissipation branch, the energy dissipation branch current rises, and then the metal oxide surge arrester (MOV) in the energy dissipation branch discharges to dissipate energy. At the same time, it triggers the conduction of the power electronic switch assembly S1, and the residual magnetic field energy in the inductor L1 is dissipated through the energy dissipation resistor Rdisspation.
[0021] The working principle is as follows: When the system is in normal operation, the power electronic switch assembly S2 remains in the triggered state, while the power electronic switch assemblies S1, S3, and S4, and the semiconductor switch device T5 remain in the off state. The DC power supply current flows through the main current-carrying branch. When a short-circuit fault occurs in the system, it is necessary to limit the rate of rise of the short-circuit current and turn off the fast mechanical switch FMS. The whole process is divided into the following four steps.
[0022] (1) When a short circuit fault occurs, the system current rises rapidly, and the current in the current-limiting inductor L1 increases. The current-limiting inductor limits the rate of rise of the short circuit current, and a voltage is induced on the current-limiting inductor L1, which absorbs line energy while limiting the current. When a short circuit fault is detected, the power electronic switch assembly S2 is turned off and the power electronic switch assembly S3 is turned on at the same time. The power electronic switch assembly S4 is turned on or off depending on the magnitude and rate of rise of the short circuit current. At this time, the main branch current is transferred to the current-limiting branch, and the presence of the current-limiting resistor can limit the short circuit current.
[0023] (2) After the fault current limiting process, the fast mechanical switch FMS is opened, and the semiconductor switching device T5 of the commutation branch is turned on. At this time, the current is transferred from the fast mechanical switch FMS branch to the commutation branch. After the fast mechanical switch breaks the insulation, the fault current is transferred to the commutation branch.
[0024] (3) When the fault current is completely transferred to the converter branch, the semiconductor switching device T5 of the converter branch is turned off, and an overvoltage is generated at both ends of the branch. The voltage at both ends of the metal oxide surge arrester MOV rises, and the current in the semiconductor branch gradually transfers to the buffer branch, and the current in the buffer branch rises.
[0025] (4) When the voltage across the metal oxide surge arrester (MOV) reaches the operating voltage, the resistance of the energy dissipation branch decreases rapidly, and the current in the buffer branch quickly shifts to the energy dissipation branch, causing the current in the energy dissipation branch to rise. Subsequently, the MOV in the energy dissipation branch discharges to dissipate energy, and at the same time triggers the conduction of the power electronic switching component S1. The residual magnetic field energy in the inductor L1 is dissipated through the energy dissipation resistor Rdisspation. This topology can achieve bidirectional shutdown of the system current.
[0026] This specific embodiment is merely an explanation of the utility model and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of protection of this utility model.
Claims
1. A current-limiting bidirectional fast circuit breaker, characterized in that, This includes parallel current-carrying branches, current-limiting branches, converter branches, buffer branches, current-limiting inductor branches, and energy-dissipating branches; The current-carrying branch includes a fast mechanical switch FMS and a power electronic switch assembly S2 connected in series; The current-limiting branch includes power electronic switch assembly S3, power electronic switch assembly S4, and current-limiting resistor R. CL1 and current limiting resistor R CL2 The power electronic switch assembly S3 and the current-limiting resistor R CL1 and current limiting resistor R CL2 The current-limiting resistor R is connected in series. CL2 It is connected in parallel with the power electronic switch assembly S4; The commutation branch includes diodes D1-D4 and semiconductor switching device T5; The buffer branch includes a resistor R1 and a capacitor C1 connected in series; The current-limiting inductor branch includes an inductor L1, a power electronic switch assembly S1, and a power-consuming resistor Rdisspation. The power electronic switch assembly S1 and the power-consuming resistor Rdisspation are connected in series and then in parallel with the inductor L1. The energy-consuming branch includes a metal oxide surge arrester (MOV).
2. The current-limiting bidirectional fast circuit breaker according to claim 1, characterized in that, When the current from the DC power supply flows through the inductor L1, the fast mechanical switch FMS, and the power electronic switch assembly S2, a normally conducting branch is formed.
3. The current-limiting bidirectional fast circuit breaker according to claim 2, characterized in that, When a short circuit fault occurs, the power electronic switch assembly S2 is turned off and the power electronic switch assembly S3 is turned on. The power electronic switch assembly S4 is turned on based on the current magnitude and rise rate. At this time, the current in the current-carrying branch is transferred to the current-limiting branch.
4. The current-limiting bidirectional fast circuit breaker according to claim 3, characterized in that, The current is transferred to the current-limiting branch, the fast mechanical switch FMS is opened, and the semiconductor switching device T5 of the commutation branch is turned on. At this time, the current is transferred from the fast mechanical switch FMS branch to the commutation branch. After the fast mechanical switch FMS breaks and establishes insulation, the current is transferred to the commutation branch.
5. The current-limiting bidirectional fast circuit breaker according to claim 4, characterized in that, When the fault current is completely transferred to the converter branch, the semiconductor switching device T5 of the converter branch is turned off, an overvoltage is generated at both ends of the branch, the voltage across the metal oxide surge arrester MOV rises, the current in the semiconductor branch gradually transfers to the buffer branch, and the current in the buffer branch rises.
6. The current-limiting bidirectional fast circuit breaker according to claim 5, characterized in that, When the voltage across the metal oxide surge arrester (MOV) reaches the operating voltage, the resistance of the energy dissipation branch decreases rapidly, the buffer branch current quickly transfers to the energy dissipation branch, the energy dissipation branch current rises, and then the metal oxide surge arrester (MOV) in the energy dissipation branch discharges to dissipate energy. At the same time, it triggers the conduction of the power electronic switch assembly S1, and the residual magnetic field energy in the inductor L1 is dissipated through the energy dissipation resistor Rdisspation.