Glow arc current detection circuit based on comparison of current sensors

Abstract

The present application relates to a kind of arc detection circuit, specifically, it is related to arc current detection circuit based on comparison of current sensor.It includes signal acquisition circuit, transmission medium and signal comparison circuit, signal acquisition circuit includes arc signal acquisition circuit and signal filter circuit.In the present application, the current of two current transformers on a wire is compared to determine the size of arc current or the comparison signal of the current to determine whether the conductor is arcing, especially suitable for use in power distribution loop of power supply and distribution system, even in the case of larger load, load diversity, the arc situation between conductor wire and wire, wire and ground can be quickly and accurately detected, and by setting the number of arc fault current signals output in unit time reaches the set number, then the automatic counting alarm circuit outputs alarm signal, which can further avoid false alarm caused by detection error.

Description

Technical Field

[0001] This invention relates to an arcing detection circuit, and more specifically, to an arcing current detection circuit based on comparison using a current sensor. Background Technology

[0002] Arcing refers to the electric arc that occurs when contacts of electrical equipment separate when the current exceeds the equipment's capacity, or the momentary spark that occurs between conductors or between a conductor and ground when current passes through certain insulating media (such as air, conductor insulation layers, etc.). Specifically, when the voltage in a circuit exceeds the air's withstand capability, the air is ionized and becomes conductive, forming an electric arc. An electric arc is a gas discharge phenomenon, usually accompanied by high temperature and high pressure, which can lead to equipment damage and safety hazards.

[0003] CN112630502B discloses a sensor capable of simultaneously detecting DC and arcing current, comprising: a housing including an inner wall and an outer wall, with a gap between the inner and outer walls; a magnetic core located within the gap, with a pre-designed slit of a pre-sized opening on a pre-defined side wall; a PCB board including a first part and a second part, the second part being connected to the first part and embedded between the two side walls of the slit, the first part being located outside the magnetic core and abutting against the side where the slit is located; a DC current detection chip attached to the first surface of the second part; an arcing current detection chip attached to the second surface of the second part; and a signal processing module connected to the DC current detection chip and the arcing current detection chip respectively, processing and outputting the detected DC current signal and arcing current signal. This solution can be applied simultaneously to the detection of arcing current in both DC and current loops.

[0004] As mentioned in the aforementioned patent, existing arcing current detection methods generally include residual current detection and fault arcing detection.

[0005] Residual current detection: Detect the difference between the output current and the return current of the power supply circuit to determine whether there is leakage or arcing between the conductor and ground.

[0006] Fault arcing detection: This method uses changes in the voltage and current waveforms of the monitoring circuit to determine whether the conductor is arcing. This solution is currently used in the market at the end of the power distribution system, but it is prone to false alarms and its effectiveness is highly controversial. It is not currently used in high-power primary and secondary power distribution systems due to the large power and diversity of downstream loads.

[0007] In order to enable the use of all power distribution circuits and to quickly and accurately detect arcing between conductors and between conductors and ground, even under large loads and diverse load conditions, this invention proposes an arcing current detection circuit based on comparison using a current sensor. Summary of the Invention

[0008] The purpose of this invention is to provide an arcing current detection circuit based on comparison using a current sensor, in order to solve the problems mentioned in the background art.

[0009] To achieve the above objectives, the present invention provides an arcing current detection circuit based on current sensor comparison, comprising a signal acquisition circuit, a transmission medium, and a signal comparison circuit. The signal acquisition circuit includes an arcing signal acquisition circuit and a signal filtering circuit. The signal comparison circuit includes an operational comparison circuit, a microcontroller circuit, and an automatic counting alarm circuit. The arcing signal acquisition circuit is connected to the signal filtering circuit. The signal filtering circuit is connected to the operational comparison circuit or the microcontroller circuit through the transmission medium. The operational comparison circuit or the microcontroller circuit is connected to the automatic counting alarm circuit.

[0010] The arcing signal acquisition circuit is used to acquire the arcing current signal obtained by electromagnetic or current cancellation at the two ends of the conductor. The arcing current signal is rectified, amplified and filtered by the signal filtering circuit and then output to the operation and comparison circuit or the microcontroller circuit. When the number of arcing fault signals output by the operation and comparison circuit or the microcontroller circuit in a unit time reaches the number set by the automatic counting alarm circuit, the automatic counting alarm circuit outputs alarm signals in the form of sound and light, signal contacts, voltage, etc.

[0011] As a further improvement to this technical solution, the arcing signal acquisition circuit includes current transformers CT1, CT2, and CT3, and a sampling resistor, wherein,

[0012] The current transformers CT1 and CT2 are respectively installed at the beginning and end of the conductor, and the secondary sides of the current transformers CT1 and CT2 pass through the current transformer CT3 in opposite directions.

[0013] The current transformer CT3 is connected to the sampling resistor, and the sampling resistor is connected to the signal filtering circuit.

[0014] As a further improvement to this technical solution, the current transformers CT1 and CT2 are respectively installed at the beginning and end of the conductor, and the secondary outputs of the current transformers CT1 and CT2 are connected in reverse parallel to the sampling resistor, which is connected to the signal filtering circuit.

[0015] As a further improvement to this technical solution, the signal filtering circuit includes operational amplifiers U1-1, U1-2, and U2-1, and peripheral circuitry, wherein:

[0016] The peripheral circuit includes diodes D1, D2, D3, D4, resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, and capacitors C1 and C2, wherein diodes D1 and D2 are connected in reverse parallel.

[0017] The arcing current signal is input to pin 2 of operational amplifier U1-1 via resistor R2, and pin 3 of operational amplifier U1-1 is grounded;

[0018] The positive terminal of diode D3 is connected to pin 1 of operational amplifier U1-1, and the negative terminal of diode D3 is connected to pin 2 of operational amplifier U1-1;

[0019] The negative terminal of diode D4 is connected to pin 1 of operational amplifier U1-1, the positive terminal of diode D4 is connected to one end of resistor R5, the other end of resistor R5 is connected to pin 6 of operational amplifier U1-2 and then connected to one end of resistor R4, the other end of resistor R4 is connected to one end of resistor R1, the other end of resistor R1 is grounded, one end of resistor R3 is connected to pin 2 of operational amplifier U1-1, and the other end of resistor R3 is connected to the positive terminal of diode D4.

[0020] The resistor R6 and the capacitor C1 are connected in parallel and then connected to pins 6 and 7 of the operational amplifier U1-2;

[0021] Pin 7 of operational amplifier U1-2 is connected to pin 3 of operational amplifier U2-1;

[0022] One end of the resistor R7 is connected to pin 2 of the operational amplifier U2-1, and the other end of the resistor R7 is grounded.

[0023] One end of the resistor R8 is connected to pin 1 of the operational amplifier U2-1, and the other end of the resistor R8 is connected to pin 2 of the operational amplifier U2-1.

[0024] One end of the resistor R9 is connected to pin 1 of the operational amplifier U2-1, and the other end of the resistor R9 is connected to the capacitor C2. The capacitor C2 is output to the signal comparison circuit through the transmission medium.

[0025] As a further improvement to this technical solution, the operational comparator circuit includes operational amplifier U2-2.

[0026] The arcing current signal is input to pin 5 of the operational amplifier U2-2, and the reference voltage REF2.5V is input to pin 6 of the operational amplifier U2-2 after being divided by resistor R10.

[0027] As a further improvement to this technical solution, the microcontroller circuit includes a microcontroller U3.

[0028] The arcing current signal is rectified, amplified, and filtered by the signal filtering circuit, and then connected to the analog input channels of pins 40, 41, 42, 43, 44, 1, 2, and 3 of the microcontroller U3. The digital output terminals of pins 8, 9, 10, 11, 12, 13, 18, and 19 of the microcontroller U3 output arcing fault signals to the automatic counting alarm circuit. At the same time, pins 5 and 7 of the microcontroller U3 transmit the arcing current and alarm signals to other devices or monitoring platforms through the subsequent communication interface circuit.

[0029] As a further improvement to this technical solution, the automatic counting alarm circuit includes a counter circuit and an alarm connected to the counter circuit. The arithmetic comparison circuit or the microcontroller circuit is connected to the counter circuit. The counter circuit is used to continuously record and update the number of times the arcing fault signal is input. When the number of arcing fault signals input by the arithmetic comparison circuit or the microcontroller circuit within a unit time reaches a preset threshold, the counter circuit will send a trigger signal to the alarm. After receiving the trigger signal, the alarm will output an alarm signal.

[0030] As a further improvement to this technical solution, the transmission medium can transmit power parameters via wires, optical fibers, wireless signals, or mobile network signals.

[0031] As a further improvement to this technical solution, the operational amplifiers U1-1 and U1-2 are both OPA2188 zero-drift operational amplifiers, and the operational amplifier U2-1 is an LM358 chip.

[0032] As a further improvement to this technical solution, the operational amplifier U2-2 is an LM358 chip.

[0033] As a further improvement to this technical solution, the microcontroller U3 is an STC12C5A08AD-35I-LQFP44 microcontroller.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] In this arc current detection circuit based on current sensor comparison, two current transformers are installed at the beginning and end of the conductor. The secondary currents of the two current transformers are passed through a third current transformer, which generates a magnetic field for comparison to obtain the arc current signal. Alternatively, the currents collected by the two transformers can be directly output to a common resistor for comparison. Or, the arc current of the conductor can be obtained by comparison after passing through a comparator circuit and some other amplification circuits.

[0036] The arcing current signal is directly detected by the sensor through the direct cancellation method of the current signal collected at both ends of the conductor. Then, the arcing current signal is amplified and rectified and processed by the operation and comparison circuit or the microcontroller circuit to output the arcing fault signal. When the number of arcing fault current signals output by the operation and comparison circuit or the microcontroller circuit in a unit time reaches the number set by the automatic counting alarm circuit, the automatic counting alarm circuit will output an alarm signal.

[0037] The method compares and processes the current collected by two current transformers on a conductor to determine the magnitude of the arcing current or the comparison signal of the current, thereby judging whether the conductor is arcing. It is particularly suitable for use in power distribution circuits of power supply and distribution systems. Even under large loads and diverse load conditions, it can quickly and accurately detect arcing between conductors or between conductors and ground. Furthermore, by setting the number of arcing fault current signals output per unit time to reach a set number, the automatic counting alarm circuit can output an alarm signal, which can further avoid false alarms caused by detection errors. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0039] Figure 2 The arc signal acquisition circuit of the present invention Figure 1 ;

[0040] Figure 3 The arc signal acquisition circuit of the present invention Figure 2 ;

[0041] Figure 4 This is a circuit diagram of the signal filtering circuit of the present invention;

[0042] Figure 5 This is a circuit diagram of the operational comparison circuit of the present invention;

[0043] Figure 6 This is the circuit diagram of the microcontroller of the present invention. Detailed Implementation

[0044] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] In power supply and distribution systems, conductors such as cables and copper busbars are used to transmit electrical energy. In such cases, the insulation layer between conductors is often damaged or aged, leading to poor insulation and arcing between conductors and between conductors and ground. This arcing further exacerbates the conductor defects, creating a vicious cycle. In severe cases, it can lead to fires and explosions, causing significant losses to the entire power supply system and posing a serious threat to personnel safety.

[0046] The existing arcing detection solutions on the market are residual current detection method and fault arcing detection method, among which,

[0047] Residual current detection: Detect the difference between the output current and the return current of the power supply circuit to determine whether there is arcing between the conductor and the ground.

[0048] Fault arcing detection: This method uses changes in circuit voltage and current to determine whether a conductor is arcing. This solution is currently used in the market at the end of the power distribution system, but it is prone to false alarms and its effectiveness is highly controversial. It is not currently used in high-power primary and secondary power distribution systems due to the large power and diversity of downstream loads.

[0049] In order to be usable in all power distribution circuits, even under large loads and diverse load conditions, it can quickly and accurately detect arcing between conductors and between conductors and ground.

[0050] Please see Figure 1 As shown, the purpose of this embodiment is to provide an arc current detection circuit based on current sensor comparison, including a signal acquisition circuit, a transmission medium and a signal comparison circuit. The signal acquisition circuit includes an arc signal acquisition circuit and a signal filtering circuit. The signal comparison circuit includes an operational comparison circuit, a microcontroller circuit and an automatic counting alarm circuit. The arc signal acquisition circuit is connected to the signal filtering circuit. The signal filtering circuit is connected to the operational comparison circuit or the microcontroller circuit through the transmission medium. The operational comparison circuit or the microcontroller circuit is connected to the automatic counting alarm circuit.

[0051] The arcing signal acquisition circuit is used to acquire the arcing current signal obtained by electromagnetic or current cancellation at both ends of the conductor. The arcing current signal is rectified, amplified and filtered by the signal filtering circuit and then output to the operational comparator circuit or the microcontroller circuit. When the number of arcing fault signals output by the operational comparator circuit or the microcontroller circuit in a unit time reaches the number set by the automatic counting alarm circuit, the automatic counting alarm circuit outputs alarm signals in the form of sound and light, signal contacts, voltage, etc.

[0052] The basic principle of this invention is to detect, calculate, and compare the arcing current by measuring the difference between the currents at the beginning and end of the same conductor to determine whether the conductor is arcing. All methods for detecting arcing current using the principle of this invention are within the scope of this patent.

[0053] In this invention, a conductor is a conductive material used to transmit electrical energy.

[0054] Arcing signal acquisition circuit: This refers to the device that acquires the current at this location, including but not limited to current transformers, Hall effect sensors, shunts, transmitters, and any other devices used for current acquisition. This embodiment uses a current transformer as an example. Figure 2 As shown, the arcing signal acquisition circuit includes current transformers CT1, CT2, and CT3, and sampling resistors.

[0055] Current transformers CT1 and CT2 are installed at the beginning and end of the conductor, respectively, and the secondary sides of current transformers CT1 and CT2 pass through current transformer CT3 in opposite directions, that is, the secondary currents of CT1 and CT2 pass through current transformer CT3 in opposite directions.

[0056] The current transformer CT3 is connected to a sampling resistor, which is then connected to a signal filtering circuit.

[0057] A current transformer is installed at each end of a conductor. The primary currents of the current transformers flow through the same current sensor in opposite directions. Since the currents I1 and I2 of the two current transformers are in opposite directions, under normal circumstances, I1 = I2. The magnetic fields generated by the current sensors are opposite and cancel each other out, resulting in an output of approximately 0. When there is an arc I3 on ​​the conductor, I1 = I2 + I3. At this time, I1 > I2. The magnetic fields generated by the current sensors are opposite, but they cannot cancel each other out, resulting in an output that is essentially a differential current signal. This signal is then amplified and rectified by a subsequent stage and output to a microcontroller circuit or compared by a subsequent stage to output an alarm signal.

[0058] The above describes one circuit connection method for current transformers, in which the secondary currents of two current transformers pass through another current transformer, generate a magnetic field in the same current transformer, and are compared to obtain the arcing current signal.

[0059] In addition, this embodiment also provides another circuit connection method, such as... Figure 3 As shown, current transformers CT1 and CT2 are installed at the beginning and end of the conductor, respectively, and the secondary outputs of current transformers CT1 and CT2 are connected in reverse parallel to sampling resistors. That is, the secondary currents of current transformers CT1 and CT2 flow in reverse through the sampling resistors, and the sampling resistors are connected to the signal filtering circuit.

[0060] The outputs of two current sensors are reverse-parallel and simultaneously output to a resistor. At this time, the currents I1 and I2 passing through the resistor are in opposite directions. Under normal circumstances, I1=I2, and the currents in the resistor are in opposite directions and equal in magnitude, thus canceling each other out, and the output is 0. When there is arcing I3 in the conductor, I1=I2+I3, and at this time I1>I2. The currents I1 and I2 passing through the resistor are in opposite directions and cannot cancel each other out, so a difference current signal is output. This signal is amplified and rectified by a subsequent stage and then output to the microcontroller circuit or compared by a subsequent stage to output an alarm signal.

[0061] That is, the secondary sides of two current transformers are connected in reverse parallel, the current is output to the same sampling resistor, the current is compared, and the arcing current signal is obtained.

[0062] like Figure 4 As shown, the signal filtering circuit includes operational amplifiers U1-1, U1-2, U2-1 and peripheral circuits, wherein:

[0063] The current signal output from the arcing signal acquisition circuit is sent to the sampling resistor to obtain the arcing current signal;

[0064] The peripheral circuit includes diodes D1, D2, D3, D4, resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, and capacitors C1 and C2. Diodes D1 and D2 are connected in reverse parallel, and the two diodes D1 and D2 connected in reverse parallel serve as signal protection clamps.

[0065] The arcing current signal is input to pin 2 of operational amplifier U1-1 through resistor R2, and pin 3 of operational amplifier U1-1 is grounded;

[0066] The positive terminal of diode D3 is connected to pin 1 of operational amplifier U1-1, and the negative terminal of diode D3 is connected to pin 2 of operational amplifier U1-1.

[0067] The negative terminal of diode D4 is connected to pin 1 of operational amplifier U1-1, the positive terminal of diode D4 is connected to one end of resistor R5, the other end of resistor R5 is connected to pin 6 of operational amplifier U1-2 and then connected to one end of resistor R4, the other end of resistor R4 is connected to one end of resistor R1, the other end of resistor R1 is grounded, one end of resistor R3 is connected to pin 2 of operational amplifier U1-1, and the other end of resistor R3 is connected to the positive terminal of diode D4.

[0068] Resistor R6 and capacitor C1 are connected in parallel and then connected to pins 6 and 7 of operational amplifier U1-2;

[0069] Pin 7 of operational amplifier U1-2 is connected to pin 3 of operational amplifier U2-1;

[0070] One end of resistor R7 is connected to pin 2 of operational amplifier U2-1, and the other end of resistor R7 is grounded;

[0071] One end of resistor R8 is connected to pin 1 of operational amplifier U2-1, and the other end of resistor R8 is connected to pin 2 of operational amplifier U2-1.

[0072] One end of resistor R9 is connected to pin 1 of operational amplifier U2-1, and the other end of resistor R9 is connected to capacitor C2. Capacitor C2 is output to the signal comparison circuit through the transmission medium.

[0073] Among them, operational amplifiers U1-1 and U1-2 are both OPA2188 type zero-drift operational amplifiers, and operational amplifier U2-1 is preferably an LM358 chip.

[0074] The OPA2188 zero-drift operational amplifier is a high-performance operational amplifier featuring low noise, zero drift, and rail-to-rail output. It utilizes TI's proprietary auto-zeroing technology to provide low offset voltage (maximum 25 μV) and near-zero drift (0.03 μV / °C) over time and temperature ranges.

[0075] Key features

[0076] Low offset voltage: 25μV maximum

[0077] Zero drift: 0.03 μV / °C

[0078] Low noise: 8.8 nV / √Hz (0.25μVPP noise in the range of 0.1Hz to 10Hz)

[0079] Excellent DC accuracy: Power Supply Rejection Ratio (PSRR) of 142dB and Common Mode Rejection Ratio (CMRR) of 146dB.

[0080] High-gain bandwidth: 2MHz

[0081] Static current: 475μA (maximum)

[0082] Wide power supply voltage: ±2V to ±18V.

[0083] The signal current comparison circuit outputs the comparison result, which can be displayed locally and used independently for control, or uploaded to a monitoring backend via network for network monitoring, control, and protection. Alternatively, the current signals collected at both ends of the conductor can be amplified before comparison to obtain the arcing current signal. The core principle is to collect and compare the currents at both ends of the conductor to determine the magnitude of the arcing current. Any use of the arc detection principle of this invention for arc current detection falls within the scope of this patent.

[0084] Transmission medium: a medium used to transmit electrical parameters such as current, including but not limited to wires, optical fibers, wireless signals, mobile network signals, and all other devices used to transmit current signals.

[0085] like Figure 5 As shown, the operational comparator circuit includes operational amplifier U2-2.

[0086] The arcing current signal is input to pin 5 of operational amplifier U2-2. The reference voltage REF2.5V is divided by resistor R10 and then input to pin 6 of operational amplifier U2-2. The comparison value of the arcing current signal can be adjusted by adjusting the voltage division of resistor R10. When the arcing current signal voltage exceeds the comparison value, the arcing fault signal is output from pin 7 of operational amplifier U2-1 to the automatic counting alarm circuit.

[0087] The operational amplifier U2-2 is preferably an LM358 chip.

[0088] like Figure 6 As shown, the microcontroller circuit includes microcontroller U3.

[0089] The arcing current signals from multiple conductors are rectified, amplified, and filtered by the signal filtering circuit, and then connected to the analog input channels (pins 40, 41, 42, 43, 44, 1, 2, and 3) of the microcontroller U3 for analog-to-digital conversion. When the input arcing current signal exceeds the set value, the digital output terminals (pins 8, 9, 10, 11, 12, 13, 18, and 19) of the microcontroller U3 output an arcing fault signal to the automatic counting alarm circuit.

[0090] Pins 5 and 7 of the microcontroller U3 transmit arcing current and alarm signals to other devices or monitoring platforms via communication interface circuits such as RS485, CAN, and 4G modules.

[0091] The arcing current value and alarm signal are output as communication signals through pins 5 and 7 of the microcontroller U3. These signals can be transmitted to the management platform via the communication interface circuit and network.

[0092] The preferred microcontroller U3 is the STC12C5A08AD-35I-LQFP44.

[0093] In addition, to prevent false alarms, this invention includes an automatic counting alarm circuit, which includes a counter circuit and an alarm connected to the counter circuit. An operational comparison circuit or a microcontroller circuit is connected to the counter circuit. The counter circuit is used to continuously record and update the number of arc fault signals input by the operational comparison circuit or the microcontroller circuit. When the number of arc fault signals input by the operational comparison circuit or the microcontroller circuit reaches a preset threshold within a unit time, the counter circuit will send a trigger signal to the alarm. After receiving the trigger signal, the alarm will output alarm signals in the form of sound and light, signal contacts, voltage, etc., thereby avoiding false alarms.

[0094] In this invention, two current transformers are installed at both ends of the conductor. The secondary currents of the two current transformers are passed through a third current transformer, which generates a magnetic field for comparison to obtain the arcing current signal. Alternatively, the currents collected by the two transformers can be directly output to a common resistor for comparison. Or, the arcing current of the conductor can be obtained through a comparator circuit and other amplification circuits. After the arcing current signal is amplified and rectified, it is processed by an operational comparator circuit or a microcontroller circuit to output an arcing fault signal. When the number of arcing fault current signals output by the operational comparator circuit or the microcontroller circuit in a unit time reaches the number set by the automatic counting alarm circuit, the automatic counting alarm circuit outputs an alarm signal. At the same time, the communication interface pins 5 and 7 of the microcontroller U3 transmit the arcing current and alarm signal to other devices or monitoring platforms via subsequent communication interface circuits such as RS485, CAN, and 4G modules.

[0095] The method compares and processes the current collected by two current transformers on a conductor to determine the magnitude of the arcing current or the comparison signal of the current, thereby judging whether the conductor is arcing. It is particularly suitable for use in power distribution circuits of power supply and distribution systems. Even under large loads and diverse load conditions, it can quickly and accurately detect arcing between conductors or between conductors and ground. Furthermore, by setting the number of arcing fault current signals output per unit time to reach a set number, the automatic counting alarm circuit can output an alarm signal, which can further avoid false alarms caused by detection errors.

[0096] In summary, the method of obtaining the arcing current signal by passing the conductor through two current transformers in opposite directions at both ends of the conductor and then through a third current transformer or a common sampling resistor is consistent with the principle of this patent and both fall within the scope of this patent.

[0097] This invention is low in cost and can detect conductor arcing defects in a short time, regardless of the load size or the variety of load conditions.

[0098] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An arc current detection circuit based on comparison using a current sensor, characterized in that: The system includes a signal acquisition circuit, a transmission medium, and a signal comparison circuit. The signal acquisition circuit includes an arc signal acquisition circuit and a signal filtering circuit. The signal comparison circuit includes an operational comparison circuit, a microcontroller circuit, and an automatic counting alarm circuit. The arc signal acquisition circuit is connected to the signal filtering circuit. The signal filtering circuit is connected to the operational comparison circuit or the microcontroller circuit through the transmission medium. The operational comparison circuit or the microcontroller circuit is connected to the automatic counting alarm circuit. The arcing signal acquisition circuit is used to acquire the arcing current signal obtained by electromagnetic or current cancellation of the current at both ends of the conductor. The arcing current signal is rectified, amplified and filtered by the signal filtering circuit and then output to the operation and comparison circuit or the microcontroller circuit. When the number of arcing fault signals output by the operation and comparison circuit or the microcontroller circuit in a unit time reaches the number set by the automatic counting alarm circuit, the automatic counting alarm circuit outputs an alarm signal. The arcing signal acquisition circuit includes current transformers CT1, CT2, and CT3, and sampling resistors, wherein... The current transformers CT1 and CT2 are respectively installed at the beginning and end of the conductor, and the secondary sides of the current transformers CT1 and CT2 pass through the current transformer CT3 in opposite directions. The current transformer CT3 is connected to the sampling resistor, and the sampling resistor is connected to the signal filtering circuit; Alternatively, the arcing signal acquisition circuit includes current transformers CT1 and CT2 and a sampling resistor. The current transformers CT1 and CT2 are respectively installed at the beginning and end of the conductor, and the secondary outputs of the current transformers CT1 and CT2 are connected in reverse parallel to the sampling resistor. The sampling resistor is connected to the signal filtering circuit.

2. The arcing current detection circuit based on current sensor comparison according to claim 1, characterized in that: The signal filtering circuit includes operational amplifiers U1-1, U1-2, U2-1 and peripheral circuitry, wherein: The peripheral circuit includes diodes D1, D2, D3, D4, resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, and capacitors C1 and C2, wherein diodes D1 and D2 are connected in reverse parallel. The arcing current signal is input to pin 2 of operational amplifier U1-1 via resistor R2, and pin 3 of operational amplifier U1-1 is grounded; The positive terminal of diode D3 is connected to pin 1 of operational amplifier U1-1, and the negative terminal of diode D3 is connected to pin 2 of operational amplifier U1-1; The negative terminal of diode D4 is connected to pin 1 of operational amplifier U1-1, the positive terminal of diode D4 is connected to one end of resistor R5, the other end of resistor R5 is connected to pin 6 of operational amplifier U1-2 and then connected to one end of resistor R4, the other end of resistor R4 is connected to one end of resistor R1, the other end of resistor R1 is grounded, one end of resistor R3 is connected to pin 2 of operational amplifier U1-1, and the other end of resistor R3 is connected to the positive terminal of diode D4. The resistor R6 and the capacitor C1 are connected in parallel and then connected to pins 6 and 7 of the operational amplifier U1-2; Pin 7 of operational amplifier U1-2 is connected to pin 3 of operational amplifier U2-1; One end of the resistor R7 is connected to pin 2 of the operational amplifier U2-1, and the other end of the resistor R7 is grounded. One end of the resistor R8 is connected to pin 1 of the operational amplifier U2-1, and the other end of the resistor R8 is connected to pin 2 of the operational amplifier U2-1. One end of the resistor R9 is connected to pin 1 of the operational amplifier U2-1, and the other end of the resistor R9 is connected to the capacitor C2. The capacitor C2 is output to the signal comparison circuit through the transmission medium. The operational amplifiers U1-1 and U1-2 are both OPA2188 zero-drift operational amplifiers, and the operational amplifier U2-1 is an LM358 chip.

3. The arcing current detection circuit based on current sensor comparison according to claim 1, characterized in that: The operational comparator circuit includes operational amplifier U2-2. The arcing current signal is input to pin 5 of the operational amplifier U2-2, and the reference voltage REF2.5V is input to pin 6 of the operational amplifier U2-2 after being divided by resistor R10. The operational amplifier U2-2 is an LM358 chip.

4. The arcing current detection circuit based on current sensor comparison according to claim 3, characterized in that: The microcontroller circuit includes microcontroller U3. The arcing current signal is rectified, amplified, and filtered by the signal filtering circuit, and then connected to the analog input channels of pins 40, 41, 42, 43, 44, 1, 2, and 3 of the microcontroller U3. The digital output terminals 8, 9, 10, 11, 12, 13, 18, and 19 of the microcontroller U3 output the arcing fault signal to the automatic counting alarm circuit. Pins 5 and 7 of the microcontroller U3 transmit arcing current and alarm signals to other devices or monitoring platforms via the subsequent communication interface circuit. The microcontroller U3 is an STC12C5A08AD-35I-LQFP44 microcontroller.

5. The arcing current detection circuit based on current sensor comparison according to claim 4, characterized in that: The automatic counting alarm circuit includes a counter circuit and an alarm connected to the counter circuit. The arithmetic comparison circuit or the microcontroller circuit is connected to the counter circuit. The counter circuit is used to continuously record and update the number of times the arcing fault signal is input. When the number of arcing fault signals input by the arithmetic comparison circuit or the microcontroller circuit within a unit time reaches a preset threshold, the counter circuit sends a trigger signal to the alarm. After receiving the trigger signal, the alarm outputs an alarm signal.

6. The arcing current detection circuit based on current sensor comparison according to claim 1, characterized in that: The transmission medium transmits electrical parameters via methods including wires, optical fibers, wireless signals, or mobile network signals.

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