Intelligent power distribution cabinet fault identification system

Abstract

This invention belongs to the field of power distribution cabinet technology and proposes an intelligent power distribution cabinet fault identification system. It includes a high-voltage pulse generation circuit for applying pulses across the circuit breaker coil. The high-voltage pulse generation circuit includes a driver chip U2, diode D7, capacitor C5, MOSFETs Q3 and Q4. The drain of MOSFET Q3 is connected to the positive terminal of the high-voltage power supply, and the source of MOSFET Q3 is connected to the drain of MOSFET Q4. The source of MOSFET Q4 is grounded. The system also includes a coil current detection circuit for detecting the circuit breaker coil current and a coil voltage detection circuit for detecting the circuit breaker coil voltage. Both the coil current detection circuit and the coil voltage detection circuit are connected to the main control chip. This technical solution solves the problem of poor fault monitoring performance in existing power distribution cabinet technologies.

Description

Technical Field

[0001] This invention belongs to the field of power distribution cabinet technology and relates to an intelligent power distribution cabinet fault identification system. Background Technology

[0002] Distribution cabinets are widely used in power systems for power generation, transmission, and distribution. Their main function is to distribute and control power to electrical equipment. They also provide power outage protection in case of overload, short circuit, or leakage. With urban development, the coverage area of ​​the power grid is expanding, and consequently, the demand for distribution cabinets is increasing. Because distribution cabinets are easy to install, they can be placed in various complex working environments. However, this also leads to a greater number of potential causes of failure, which, if not detected in time, can affect the operation of the power system. Summary of the Invention

[0003] This invention proposes an intelligent power distribution cabinet fault identification system, which solves the problem of poor fault monitoring effect in existing power distribution cabinet technologies.

[0004] The technical solution of this invention is implemented as follows: including

[0005] A high-voltage pulse generating circuit is used to apply voltage across the circuit breaker coil; the high-voltage pulse generating circuit includes a driver chip U2, diode D7, capacitor C5, MOSFET Q3, and MOSFET Q4.

[0006] The drain of MOSFET Q3 is connected to the positive terminal of the high-voltage power supply, the source of MOSFET Q3 is connected to the drain of MOSFET Q4, and the source of MOSFET Q4 is grounded.

[0007] The high-end logic input HIN and low-end logic input LIN of the driver chip U2 are both connected to the main control chip. The anode of the diode D7 is connected to the 15V power supply, and the cathode of the diode D7 is connected to the floating power supply voltage terminal VB of the driver chip U2. The floating power supply voltage terminal VB of the driver chip U2 is connected to the floating power supply offset voltage terminal VS through capacitor C5. The floating power supply offset voltage terminal VS of the driver chip U2 is connected to the source of the MOSFET Q3. The high-end output HO of the driver chip U2 is connected to the gate of the MOSFET Q3, and the low-end output LO of the driver chip U2 is connected to the gate of the MOSFET Q4. The common terminal COM of the driver chip U2 is connected to the source of the MOSFET Q4.

[0008] The source of the MOS transistor Q3 serves as the positive output terminal of the high-voltage pulse generation circuit, and the source of the MOS transistor Q4 serves as the negative output terminal of the high-voltage pulse generation circuit.

[0009] A coil current detection circuit is used to detect the coil current of a circuit breaker.

[0010] A coil voltage detection circuit is used to detect the coil voltage of a circuit breaker; both the coil current detection circuit and the coil voltage detection circuit are connected to the main control chip.

[0011] Furthermore, it also includes Zener diodes D8 and D6. The cathode of Zener diode D8 is connected to the gate of MOSFET Q3, and the anode of Zener diode D8 is connected to the source of MOSFET Q3. The cathode of Zener diode D6 is connected to the gate of MOSFET Q4, and the anode of Zener diode D6 is connected to the source of MOSFET Q4.

[0012] Furthermore, it also includes a power conversion circuit, which comprises a first rectifier circuit, an inverter circuit, a boost circuit, and a second rectifier circuit connected in sequence. The input terminal of the first rectifier circuit is connected to the AC power input line, and the output of the second rectifier circuit serves as a high-voltage power supply.

[0013] The boost circuit includes a boost transformer T1, the first input terminal of which is connected to the first output terminal of the first rectifier circuit via a capacitor C7. It also includes a capacitor C8 and a resistor R5 connected in series. One end of the capacitor C8 is connected to the first input terminal of the boost transformer T1, and one end of the resistor R5 is connected to the second input terminal of the boost transformer T1.

[0014] Furthermore, the inverter circuit includes MOSFETs Q1 and Q2, diodes D27 and D28. The anode of diode D27 is connected to the first output terminal of the first rectifier circuit, the cathode of diode D27 is connected to the drain of MOSFET Q1, the source of MOSFET Q1 is connected to the anode of diode D28, the cathode of diode D28 is connected to the drain of MOSFET Q2, the source of MOSFET Q2 is connected to the second output terminal of the first rectifier circuit, and the gates of both MOSFET Q1 and MOSFET Q2 are connected to the main control chip.

[0015] It also includes diodes D29 and D30. The anode of diode D29 is connected to the source of MOS transistor Q1, the cathode of diode D29 is connected to the anode of diode D27, the anode of diode D30 is connected to the source of MOS transistor Q2, and the cathode of diode D30 is connected to the anode of diode D28.

[0016] Furthermore, it also includes a transformer output three-phase imbalance detection circuit, which comprises three output voltage detection circuits with identical circuit structures. The input terminals of the three output voltage detection circuits are respectively connected to the three-phase output of the transformer, and the output terminals of the three output voltage detection circuits are all connected to the main control chip.

[0017] One of the output voltage detection circuits includes a voltage sampling circuit, a third rectifier circuit, and a comparator circuit connected in sequence. The output of the comparator circuit serves as the output of the output voltage detection circuit and is connected to the main control chip.

[0018] Furthermore, the voltage sampling circuit includes resistors R14, R15, R17, R22, R20, R19, and R18 connected in series. One end of resistor R14 is connected to the U-phase output terminal of the transformer, and one end of resistor R18 is connected to the N-line of the transformer. The series connection point of resistor R22 and resistor R17 is connected to the first input terminal of the third rectifier circuit, and the series connection point of resistor R22 and resistor R20 is connected to the second input terminal of the third rectifier circuit.

[0019] Furthermore, the third rectifier circuit includes a rectifier bridge composed of diodes D21, D22, D23 and D24, and a filter capacitor C6 is connected in parallel at the output terminal of the rectifier bridge.

[0020] Furthermore, the comparator circuit includes operational amplifier U7A, operational amplifier U7B, diode D26, and diode D25. The output terminal of the third rectifier circuit is connected to the non-inverting input terminal of operational amplifier U7A and the inverting input terminal of operational amplifier U7B, respectively.

[0021] The inverting input terminal of operational amplifier U7A is connected to the reference voltage VREF1, and the non-inverting input terminal of operational amplifier U7B is connected to the reference voltage VREF2.

[0022] The output terminal of operational amplifier U7A is connected to the anode of diode D26, the output terminal of operational amplifier U7B is connected to the anode of diode D25, the cathode of diode D26 is connected to the cathode of diode D25, and the cathode of diode D26 serves as the output of the comparator circuit, which is connected to the main control chip.

[0023] The working principle and beneficial effects of this invention are as follows:

[0024] Circuit breakers are a crucial component of distribution cabinets, and their reliable opening and closing control is fundamental to ensuring the safe operation of the power distribution system. Prolonged operation of the circuit breaker coil leads to aging of the inter-turn insulation, resulting in decreased coil driving force and unreliable opening and closing of the circuit breaker. This embodiment applies a high-voltage pulse (with the output time controlled within 0.1ms to avoid affecting the normal operation of the coil) across the circuit breaker coil. A coil voltage detection circuit monitors the coil voltage in real time, and a coil current detection circuit monitors the coil current in real time. The main control chip plots the V / I characteristic curve of the coil based on the coil voltage and current, and compares it with a standard V / I characteristic curve to determine the aging condition of the inter-turn insulation. Measures are taken in time before the coil insulation performance deteriorates significantly, preventing unreliable opening and closing of the circuit breaker due to severe insulation degradation.

[0025] The high-voltage pulse generation circuit works as follows: When it first starts working, the main control chip outputs PWM2A at a low level and PWM2B at a high level. This results in the high-side output HO of the driver chip U2 being low and the low-side output LO being high. MOSFET Q3 is off, and MOSFET Q4 is on, allowing the 15V power supply to charge capacitor C5 through diode D7. When the main control chip outputs PWM2A at a high level and PWM2B at a low level, the driver chip U2's high-side output HO is high and the low-side output LO is low. Since capacitor C5 is fully charged, a positive voltage exists between the gate and source of MOSFET Q3. When transistor Q3 is turned on, a circuit is formed between the positive terminal HV+ of the high-voltage power supply, the circuit breaker coil L1, and the positive terminal HV- of the high-voltage power supply, and the high-voltage power supply is applied across the two ends of the circuit breaker coil L1. Subsequently, the main control chip outputs PWM2A as low level and PWM2B as high level again. The high-side output HO of the driver chip U2 is low level, and the low-side output LO is high level. MOSFET Q3 is turned off, and the circuit breaker coil L1 is disconnected from the high-voltage power supply. At the same time, MOSFET Q4 is turned on, and the circuit breaker coil L1 discharges quickly through MOSFET Q4, effectively ensuring the steepness of the falling edge of the high-voltage pulse and avoiding the high-voltage power supply being applied across the two ends of the circuit breaker coil L1 for too long. Attached Figure Description

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0027] Figure 1 This is a schematic diagram of the high-voltage pulse generation circuit in this invention;

[0028] Figure 2 This is a schematic diagram of the power conversion circuit in this invention;

[0029] Figure 3 This is a schematic diagram of the transformer output three-phase imbalance detection circuit in this invention;

[0030] In the diagram: 1 High-voltage pulse generation circuit, 2 Power conversion circuit, 3 Transformer output three-phase imbalance detection circuit. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] like Figure 1 As shown, this embodiment includes an intelligent power distribution cabinet fault identification system, comprising:

[0033] A high-voltage pulse generating circuit is used to apply a pulse across the circuit breaker coil; the high-voltage pulse generating circuit includes a driver chip U2, diode D7, capacitor C5, MOSFET Q3, and MOSFET Q4.

[0034] The drain of MOSFET Q3 is connected to the positive terminal of the high-voltage power supply, the source of MOSFET Q3 is connected to the drain of MOSFET Q4, and the source of MOSFET Q4 is grounded.

[0035] The high-side logic input HIN and low-side logic input LIN of driver chip U2 are both connected to the main control chip. The anode of diode D7 is connected to the 15V power supply, and the cathode of diode D7 is connected to the floating power supply voltage terminal VB of driver chip U2. The floating power supply voltage terminal VB of driver chip U2 is connected to the floating power supply offset voltage terminal VS through capacitor C5. The floating power supply offset voltage terminal VS of driver chip U2 is connected to the source of MOSFET Q3. The high-side output HO of driver chip U2 is connected to the gate of MOSFET Q3, and the low-side output LO of driver chip U2 is connected to the gate of MOSFET Q4. The common terminal COM of driver chip U2 is connected to the source of MOSFET Q4.

[0036] The source of MOSFET Q3 serves as the positive output terminal of the high-voltage pulse generation circuit, and the source of MOSFET Q4 serves as the negative output terminal of the high-voltage pulse generation circuit.

[0037] A coil current detection circuit is used to detect the coil current of a circuit breaker.

[0038] The coil voltage detection circuit is used to detect the coil voltage of the circuit breaker; both the coil current detection circuit and the coil voltage detection circuit are connected to the main control chip.

[0039] Circuit breakers are a crucial component of distribution cabinets, and their reliable opening and closing control is fundamental to ensuring the safe operation of the power distribution system. Prolonged operation of the circuit breaker coil leads to aging of the inter-turn insulation, resulting in decreased coil driving force and unreliable opening and closing of the circuit breaker. This embodiment applies a high-voltage pulse (with the output time controlled within 0.1ms to avoid affecting the normal operation of the coil) across the circuit breaker coil. A coil voltage detection circuit monitors the coil voltage in real time, and a coil current detection circuit monitors the coil current in real time. The main control chip plots the V / I characteristic curve of the coil based on the coil voltage and current, and compares it with a standard V / I characteristic curve to determine the aging condition of the inter-turn insulation. Measures are taken in time before the coil insulation performance deteriorates significantly, preventing unreliable opening and closing of the circuit breaker due to severe insulation degradation.

[0040] The high-voltage pulse generation circuit works as follows: When it first starts working, the main control chip outputs PWM2A at a low level and PWM2B at a high level. This results in the high-side output HO of the driver chip U2 being low and the low-side output LO being high. MOSFET Q3 is off, and MOSFET Q4 is on, allowing the 15V power supply to charge capacitor C5 through diode D7. When the main control chip outputs PWM2A at a high level and PWM2B at a low level, the driver chip U2's high-side output HO is high and the low-side output LO is low. Since capacitor C5 is fully charged, a positive voltage exists between the gate and source of MOSFET Q3. When transistor Q3 is turned on, a circuit is formed between the positive terminal HV+ of the high-voltage power supply, the circuit breaker coil L1, and the positive terminal HV- of the high-voltage power supply, and the high-voltage power supply is applied across the two ends of the circuit breaker coil L1. Subsequently, the main control chip outputs PWM2A as low level and PWM2B as high level again. The high-side output HO of the driver chip U2 is low level, and the low-side output LO is high level. MOSFET Q3 is turned off, and the circuit breaker coil L1 is disconnected from the high-voltage power supply. At the same time, MOSFET Q4 is turned on, and the circuit breaker coil L1 discharges quickly through MOSFET Q4, effectively ensuring the steepness of the falling edge of the high-voltage pulse and avoiding the high-voltage power supply being applied across the two ends of the circuit breaker coil L1 for too long.

[0041] It should be noted that the main control chip in this embodiment can be a general-purpose microcontroller, DSP, ARM, or other control chip. In this embodiment, the ARM chip STM32F103 is specifically used. The coil current detection circuit and the coil voltage detection circuit are conventional detection circuits in this field, and will not be described in detail here for the sake of brevity.

[0042] Furthermore, it also includes Zener diodes D8 and D6, such as... Figure 1As shown, the cathode of Zener diode D8 is connected to the gate of MOSFET Q3, and the anode of Zener diode D8 is connected to the source of MOSFET Q3; the cathode of Zener diode D6 is connected to the gate of MOSFET Q4, and the anode of Zener diode D6 is connected to the source of MOSFET Q4.

[0043] Zener diode D8 is placed between the gate and source of MOSFET Q3 to absorb voltage spikes and prevent excessive voltage from being applied to the gate and source of MOSFET Q3; at the same time, Zener diode D6 is placed between the gate and source of MOSFET Q4 to prevent excessive voltage from being applied to the gate and source of MOSFET Q3.

[0044] Furthermore, it also includes power conversion circuitry, such as... Figure 2 As shown, the power conversion circuit includes a first rectifier circuit, an inverter circuit, a boost circuit, and a second rectifier circuit connected in sequence. The input terminal of the first rectifier circuit is connected to the AC power input line, and the output of the second rectifier circuit serves as the high-voltage power supply.

[0045] The boost circuit includes a boost transformer T1, the first input terminal of which is connected to the first output terminal of the first rectifier circuit through a capacitor C7. It also includes a capacitor C8 and a resistor R5 connected in series. One end of the capacitor C8 is connected to the first input terminal of the boost transformer T1, and one end of the resistor R5 is connected to the second input terminal of the boost transformer T1.

[0046] The AC power voltage of one phase (U phase in this embodiment) from the incoming line of the distribution cabinet is input to the power conversion circuit, which outputs a high-voltage power supply for the high-voltage pulse generation circuit. The working principle of the power conversion circuit is as follows: the U phase power voltage is rectified into DC voltage by the first rectifier circuit, the DC voltage is then inverted into AC voltage Uin_1 by the inverter circuit, the AC voltage Uin_1 is stepped up by the step-up transformer, and then rectified into DC high voltage by the second rectifier circuit. Among them, capacitor C7 is a DC blocking capacitor to prevent DC components from entering the step-up transformer and causing the step-up transformer to overheat; capacitor C8 and resistor R5 can absorb high-frequency peak voltages, converting the high-frequency peak voltages into heat and dissipating it on resistor R5, thus preventing the high-frequency peak voltages from entering the step-up transformer.

[0047] Both the first and second rectifier circuits use a rectifier bridge structure composed of diodes, with the second rectifier circuit using a high-voltage rectifier diode.

[0048] Furthermore, such as Figure 2As shown, the inverter circuit includes MOSFETs Q1 and Q2, diodes D27 and D28. The anode of diode D27 is connected to the first output terminal of the first rectifier circuit, the cathode of diode D27 is connected to the drain of MOSFET Q1, the source of MOSFET Q1 is connected to the anode of diode D28, the cathode of diode D28 is connected to the drain of MOSFET Q2, the source of MOSFET Q2 is connected to the second output terminal of the first rectifier circuit, and the gates of both MOSFET Q1 and MOSFET Q2 are connected to the main control chip.

[0049] It also includes diodes D29 and D30. The anode of diode D29 is connected to the source of MOSFET Q1, the cathode of diode D29 is connected to the anode of diode D27, the anode of diode D30 is connected to the source of MOSFET Q2, and the cathode of diode D30 is connected to the anode of diode D28.

[0050] The inverter circuit adopts a half-bridge structure composed of MOSFETs Q1 and Q2, which has a simple circuit structure. When MOSFET Q1 is turned off, diodes D29 and D27 form the freewheeling circuit of MOSFET Q1. When MOSFET Q2 is turned off, diodes D30 and D28 form the freewheeling circuit of MOSFET Q2, further improving the reliability of the circuit.

[0051] Furthermore, it also includes a transformer output three-phase imbalance detection circuit, such as... Figure 3 As shown, the transformer output three-phase imbalance detection circuit includes three output voltage detection circuits with identical circuit structures. The input terminals of the three output voltage detection circuits are respectively connected to the three-phase output of the transformer, and the output terminals of the three output voltage detection circuits are all connected to the main control chip.

[0052] One of the output voltage detection circuits includes a voltage sampling circuit, a third rectifier circuit, and a comparator circuit connected in sequence. The output of the comparator circuit serves as the output of the output voltage detection circuit and is connected to the main control chip.

[0053] Furthermore, such as Figure 3 As shown, the voltage sampling circuit includes resistors R14, R15, R17, R22, R20, R19, and R18 connected in series. One end of resistor R14 is connected to the U-phase output terminal of the transformer, and one end of resistor R18 is connected to the N-line of the transformer. The series connection point of resistors R22 and R17 is connected to the first input terminal of the third rectifier circuit, and the series connection point of resistors R22 and R20 is connected to the second input terminal of the third rectifier circuit.

[0054] If the three phases of the transformer output are unbalanced, it will increase power consumption and accelerate transformer aging. In this embodiment, the transformer output three-phase imbalance detection circuit is used to accurately detect this unbalanced operating state. The specific working principle is as follows: the three output voltage detection circuits are used to detect the effective values ​​of the voltages of the U, V, and W phases of the transformer, respectively. When the effective value of the voltage of a certain phase exceeds the set range, it is determined that the transformer output is unbalanced. If this unbalanced state exceeds the set time, manual intervention is required to prevent the transformer from operating in a three-phase unbalanced state for a long time. Taking the U-phase voltage detection circuit as an example, resistors R14, R15, R17, R22, R20, R19, and R18 form a series voltage divider circuit. The voltage across resistor R14 changes proportionally to the U-phase voltage. By detecting the voltage across R22, the U-phase voltage can be detected. The voltage across resistor R22 is rectified by the third rectifier circuit to obtain its effective voltage value. This effective voltage value is connected to the comparator circuit and compared with the voltage set value. When the effective voltage value exceeds the voltage set value, the output signal of the comparator circuit jumps. When the main control chip receives this jump signal, it determines that the three phases of the transformer output are unbalanced.

[0055] Furthermore, such as Figure 3 As shown, the third rectifier circuit includes a rectifier bridge composed of diodes D21, D22, D23 and D24, and a filter capacitor C6 is connected in parallel at the output terminal of the rectifier bridge.

[0056] The voltage across resistor R22 is rectified by a rectifier bridge composed of diodes D21, D22, D23, and D24, and then filtered by capacitor C6 to obtain the effective value of the voltage across resistor R22.

[0057] Furthermore, such as Figure 3 As shown, the comparator circuit includes operational amplifier U7A, operational amplifier U7B, diode D26, and diode D25. The output of the third rectifier circuit is connected to the non-inverting input of operational amplifier U7A and the inverting input of operational amplifier U7B, respectively.

[0058] The inverting input of op-amp U7A is connected to the reference voltage VREF1, and the non-inverting input of op-amp U7B is connected to the reference voltage VREF2.

[0059] The output of operational amplifier U7A is connected to the anode of diode D26, the output of operational amplifier U7B is connected to the anode of diode D25, the cathodes of diode D26 and D25 are connected, and the cathode of diode D26 serves as the output of the comparator circuit, which is connected to the main control chip.

[0060] The reference voltages VREF1 and VREF2 are set according to the effective value range of the three-phase output voltage of the transformer. Taking the U-phase voltage as an example, when the U-phase voltage is within the normal range, the output voltage of the third rectifier circuit is less than the reference voltage VREF1 but greater than the reference voltage VREF2, and both operational amplifiers U7A and U7B output a low level. When the U-phase voltage is too high, the output voltage of the third rectifier circuit is greater than the reference voltage VREF1, and operational amplifier U7A outputs a high level. This high-level signal is connected to the main control chip. When the main control chip receives this high-level signal, it determines that the three-phase output of the transformer is unbalanced. When the U-phase voltage is too low, the output voltage of the third rectifier circuit is less than the reference voltage VREF2, and operational amplifier U7B outputs a high level. This high-level signal is connected to the main control chip, which determines that the three-phase output of the transformer is unbalanced.

[0061] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An intelligent power distribution cabinet fault identification system, wherein the power distribution cabinet includes a circuit breaker, characterized in that: include: A high-voltage pulse generating circuit is used to apply voltage across the circuit breaker coil; the high-voltage pulse generating circuit includes a driver chip U2, diode D7, capacitor C5, MOSFET Q3, and MOSFET Q4. The drain of MOSFET Q3 is connected to the positive terminal of the high-voltage power supply, the source of MOSFET Q3 is connected to the drain of MOSFET Q4, and the source of MOSFET Q4 is grounded. The high-end logic input HIN and low-end logic input LIN of the driver chip U2 are both connected to the main control chip. The anode of the diode D7 is connected to the 15V power supply, and the cathode of the diode D7 is connected to the floating power supply voltage terminal VB of the driver chip U2. The floating power supply voltage terminal VB of the driver chip U2 is connected to the floating power supply offset voltage terminal VS through capacitor C5. The floating power supply offset voltage terminal VS of the driver chip U2 is connected to the source of the MOSFET Q3. The high-end output HO of the driver chip U2 is connected to the gate of the MOSFET Q3, and the low-end output LO of the driver chip U2 is connected to the gate of the MOSFET Q4. The common terminal COM of the driver chip U2 is connected to the source of the MOSFET Q4. The source of the MOS transistor Q3 serves as the positive output terminal of the high-voltage pulse generation circuit, and the source of the MOS transistor Q4 serves as the negative output terminal of the high-voltage pulse generation circuit. A coil current detection circuit is used to detect the coil current of a circuit breaker. A coil voltage detection circuit is used to detect the coil voltage of a circuit breaker; both the coil current detection circuit and the coil voltage detection circuit are connected to the main control chip. When the main control chip outputs PWM2A at a high level and PWM2B at a low level, the high-side output HO of the driver chip U2 is at a high level, and the low-side output LO is at a low level. Since capacitor C5 is fully charged, there is a positive voltage between the gate and source of MOSFET Q3, and MOSFET Q3 is turned on. A circuit is formed between the positive terminal HV+ of the high-voltage power supply, the circuit breaker coil L1, and the positive terminal HV- of the high-voltage power supply, and the high-voltage power supply is applied across the two ends of the circuit breaker coil L1. After that, the main control chip outputs PWM2A at a low level and PWM2B at a high level again, the high-side output HO of the driver chip U2 is at a low level, and the low-side output LO is at a high level, MOSFET Q3 is turned off, and the circuit breaker coil L1 is disconnected from the high-voltage power supply. At the same time, MOSFET Q4 is turned on, and the circuit breaker coil L1 discharges quickly through MOSFET Q4, effectively ensuring the steepness of the falling edge of the high-voltage pulse and avoiding the high-voltage power supply applied across the two ends of the circuit breaker coil L1 for too long, which would affect the normal operation of the coil.

2. The intelligent power distribution cabinet fault identification system according to claim 1, characterized in that: It also includes Zener diodes D8 and D6. The cathode of Zener diode D8 is connected to the gate of MOSFET Q3, and the anode of Zener diode D8 is connected to the source of MOSFET Q3. The cathode of Zener diode D6 is connected to the gate of MOSFET Q4, and the anode of Zener diode D6 is connected to the source of MOSFET Q4.

3. The intelligent power distribution cabinet fault identification system according to claim 1, characterized in that: It also includes a power conversion circuit, which comprises a first rectifier circuit, an inverter circuit, a boost circuit, and a second rectifier circuit connected in sequence. The input terminal of the first rectifier circuit is connected to the AC power input line, and the output of the second rectifier circuit serves as a high-voltage power supply. The boost circuit includes a boost transformer T1, the first input terminal of which is connected to the first output terminal of the first rectifier circuit via a capacitor C7. It also includes a capacitor C8 and a resistor R5 connected in series. One end of the capacitor C8 is connected to the first input terminal of the boost transformer T1, and one end of the resistor R5 is connected to the second input terminal of the boost transformer T1.

4. The intelligent power distribution cabinet fault identification system according to claim 3, characterized in that: The inverter circuit includes MOSFETs Q1 and Q2, diodes D27 and D28. The anode of diode D27 is connected to the first output terminal of the first rectifier circuit, the cathode of diode D27 is connected to the drain of MOSFET Q1, the source of MOSFET Q1 is connected to the anode of diode D28, the cathode of diode D28 is connected to the drain of MOSFET Q2, the source of MOSFET Q2 is connected to the second output terminal of the first rectifier circuit, and the gates of both MOSFET Q1 and MOSFET Q2 are connected to the main control chip. It also includes diodes D29 and D30. The anode of diode D29 is connected to the source of MOS transistor Q1, the cathode of diode D29 is connected to the anode of diode D27, the anode of diode D30 is connected to the source of MOS transistor Q2, and the cathode of diode D30 is connected to the anode of diode D28.

5. The intelligent power distribution cabinet fault identification system according to claim 1, characterized in that: It also includes a transformer output three-phase imbalance detection circuit, which comprises three output voltage detection circuits with identical circuit structures. The input terminals of the three output voltage detection circuits are respectively connected to the three-phase output of the transformer, and the output terminals of the three output voltage detection circuits are all connected to the main control chip. One of the output voltage detection circuits includes a voltage sampling circuit, a third rectifier circuit, and a comparator circuit connected in sequence. The output of the comparator circuit serves as the output of the output voltage detection circuit and is connected to the main control chip.

6. The intelligent power distribution cabinet fault identification system according to claim 5, characterized in that: The voltage sampling circuit includes resistors R14, R15, R17, R22, R20, R19, and R18 connected in series. One end of resistor R14 is connected to the U-phase output terminal of the transformer, and one end of resistor R18 is connected to the N-line of the transformer. The series connection point of resistor R22 and resistor R17 is connected to the first input terminal of the third rectifier circuit, and the series connection point of resistor R22 and resistor R20 is connected to the second input terminal of the third rectifier circuit.

7. The intelligent power distribution cabinet fault identification system according to claim 5, characterized in that: The third rectifier circuit includes a rectifier bridge composed of diodes D21, D22, D23 and D24, and a filter capacitor C6 is connected in parallel at the output terminal of the rectifier bridge.

8. The intelligent power distribution cabinet fault identification system according to claim 5, characterized in that: The comparator circuit includes operational amplifier U7A, operational amplifier U7B, diode D26, and diode D25. The output terminal of the third rectifier circuit is connected to the non-inverting input terminal of operational amplifier U7A and the inverting input terminal of operational amplifier U7B, respectively. The inverting input terminal of operational amplifier U7A is connected to the reference voltage VREF1, and the non-inverting input terminal of operational amplifier U7B is connected to the reference voltage VREF2. The output terminal of operational amplifier U7A is connected to the anode of diode D26, the output terminal of operational amplifier U7B is connected to the anode of diode D25, the cathode of diode D26 is connected to the cathode of diode D25, and the cathode of diode D26 serves as the output of the comparator circuit, which is connected to the main control chip.

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