Arc discharge current detection circuit for comparison based on current sensor

Abstract

The invention relates to an arc discharge detection circuit, in particular to an arc discharge current detection circuit for comparison based on a current sensor. The circuit comprises a signal acquisition circuit, a transmission medium and a signal comparison circuit. The signal acquisition circuit comprises an arc discharge signal acquisition circuit and a signal filter circuit. According to the invention, the current collected by the two current transformers on one wire is compared and processed to obtain the size of the arc discharge current or the comparison signal of the current to judge whether the conductor is arced or not, so that the method is particularly suitable for being used in a power distribution loop of a power supply and distribution system, and even under the conditions of large load and load diversity, the arc discharge of the conductor is avoided. According to the utility model, the arc discharge condition between the conductor wires and between the wire and the ground can be rapidly and accurately detected, and the false alarm condition caused by the detection error can be further avoided by setting the mode that the number of times of outputting the arc discharge fault current signal in unit time reaches the set number of times and then outputting the alarm signal by the automatic counting alarm circuit.

Description

Technical Field

[0001] The invention relates to an arc detection circuit, in particular to an arc current detection circuit based on a current sensor for comparison. Background Art

[0002] Arcing refers to the phenomenon of instantaneous sparks between conductors or between conductors and the ground when the current in an electrical device exceeds its tolerance and the arc generated when the contacts are separated or when the current passes through certain insulating media (such as air, conductor insulation, etc.). Specifically, when the voltage in the circuit exceeds the tolerance of the air, the air will be ionized and become a conductor, forming an arc. Arcing is a gas discharge phenomenon, usually accompanied by high temperature and high pressure, which may cause equipment damage and safety hazards.

[0003] For example, CN112630502B involves a sensor that can simultaneously detect DC and arc current, including: a shell, including an inner wall and an outer wall, a gap is arranged between the inner wall and the outer wall; a magnetic core, located in the gap, with an open-loop design of a gap of a preset size on a preset side wall; a PCB board, including a first part and a second part, the second part is connected to the first part, the second part is embedded between the two side walls of the gap, and the first part is located on the outside of the magnetic core and abuts against the side where the gap is located; a DC current detection chip, attached to the first surface of the second part; an arc current detection chip, attached to the second surface of the second part; a signal processing module, respectively connected to the DC current detection chip and the arc current detection chip, to process and output the detected DC current signal and arc current signal; this scheme can be simultaneously applied to DC and current loop arc current detection.

[0004] As mentioned in the above patent, the existing arc detection schemes are generally residual current detection method and fault arc detection method, among which:

[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 the ground.

[0006] Fault arc detection: The changes in the voltage and current waveforms of the monitoring circuit are used to determine whether the conductor is arcing. This solution is currently used at the end of the distribution network in the market, but it is prone to false alarms and its effectiveness is controversial. It is basically not used in the primary and secondary distribution networks with higher power due to the large power and diversity of the subsequent loads.

[0007] In order to be able to be used in all power distribution circuits and to quickly and accurately detect arcing between conductor lines and between lines and ground even under large loads and load diversity, the present invention proposes an arcing current detection circuit based on a current sensor for comparison. Summary of the invention

[0008] The object of the present invention is to provide an arc current detection circuit based on a current sensor for comparison, so as to solve the problems raised in the above background technology.

[0009] To achieve the above-mentioned object, the present invention aims to provide an arc current detection circuit based on a current sensor for comparison, comprising a signal acquisition circuit, a transmission medium and a signal comparison circuit, wherein the signal acquisition circuit comprises an arc signal acquisition circuit and a signal filtering circuit, the signal comparison circuit comprises an operation comparison circuit, a single-chip 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 operation comparison circuit or the single-chip circuit via the transmission medium, and the operation comparison circuit or the single-chip circuit is connected to the automatic counting alarm circuit;

[0010] The arc signal acquisition circuit is used to collect the current at both ends of the conductor through electromagnetic or current cancellation to obtain an arc current signal. The arc current signal is rectified, amplified and filtered by the signal filtering circuit and then output to the operation comparison circuit or the single-chip microcomputer circuit. When the number of arc fault signals output by the operation comparison circuit or the single-chip microcomputer circuit per 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 of the technical solution, the arc signal acquisition circuit includes current transformers CT1, CT2, CT3 and sampling resistors, wherein:

[0012] The current transformers CT1 and CT2 are respectively installed at the head and tail ends of the conductor, and the secondary sides of the current transformers CT1 and CT2 respectively pass through the current transformer CT3 in the reverse direction;

[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 of the technical solution, the current transformers CT1 and CT2 are respectively installed at the head and tail ends of the conductor, and the secondary outputs of the current transformers CT1 and CT2 are inversely connected to the sampling resistor, and the sampling resistor is connected to the signal filtering circuit.

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

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

[0017] The arc voltage signal is input to the pin 2 of the operational amplifier U1-1 through the resistor R2, and the pin 3 of the operational amplifier U1-1 is grounded;

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

[0019] The cathode of the diode D4 is connected to the pin 1 of the operational amplifier U1-1, the anode of the diode D4 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to the pin 6 of the operational amplifier U1-2 and to one end of the resistor R4, and the other end of the resistor R4 is connected to the upper end of the resistor R1;

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

[0021] Pin 7 of the operational amplifier U1-2 is connected to pin 3 of the 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 the 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 outputs the signal to the signal comparison circuit through the transmission medium.

[0025] As a further improvement of the technical solution, the operational comparison circuit includes an operational amplifier U2-2,

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

[0027] As a further improvement of the technical solution, the single-chip circuit includes a single-chip microcomputer U3,

[0028] The arc 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 single-chip microcomputer U3 respectively. The digital output terminals pins 8, 9, 10, 11, 12, 13, 18 and 19 of the single-chip microcomputer U3 output arc fault signals to the automatic counting alarm circuit. At the same time, pins 5 and 7 of the single-chip microcomputer U3 transmit the arc current and alarm signal to other devices or monitoring platforms through the subsequent communication interface circuit.

[0029] As a further improvement of the present technical solution, the automatic counting alarm circuit includes a counter circuit and an alarm connected to the counter circuit, the operational comparison circuit or the single-chip microcomputer circuit is connected to the counter circuit, and the counter circuit is used to continuously record and update the number of arc fault signals input. When the number of arc fault signals input by the operational comparison circuit or the single-chip microcomputer circuit reaches a preset threshold within a unit time, the counter circuit will send a trigger signal to the alarm, and the alarm will output an alarm signal after receiving the trigger signal.

[0030] As a further improvement of the technical solution, the transmission medium transmits power parameters in the following ways: wires, optical fibers, wireless signals, and mobile network signals.

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

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

[0033] As a further improvement of the present technical solution, the single chip microcomputer U3 is a STC12C5A08AD-35I-LQFP44 single chip microcomputer.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] In the arc current detection circuit based on current sensor comparison, two current transformers are installed at both ends of the conductor, and the secondary currents of the two current transformers pass through a third current transformer, and the magnetic field generated by the third current transformer is compared to obtain an arc current signal, or the currents collected by the two transformers are directly output to a common resistor for comparison, or the currents are compared through a comparator circuit and other amplification circuits to obtain the conductor arc current;

[0036] The current signal collected from both ends of the conductor is used to directly detect the arc current signal in the sensor in a direct offset manner. The arc current signal is then amplified and rectified, and then processed and output by an operation comparison circuit or a single-chip microcomputer circuit to obtain an arc fault signal. When the number of arc fault current signals output by the operation comparison circuit or the single-chip microcomputer circuit within a unit time reaches the number set by the automatic counting alarm circuit, the automatic counting alarm circuit outputs an alarm signal.

[0037] The currents collected by two current transformers on a conductor are compared and processed to obtain the size of the arcing current or the comparison signal of the current to determine whether the conductor is arcing. It is particularly suitable for use in the power distribution circuit of the power supply and distribution system. Even in the case of large loads and load diversity, it can quickly and accurately detect the arcing between conductor lines and between lines and ground. In addition, by setting the number of arcing fault current signals output per unit time to reach the set number, the automatic counting alarm circuit will output an alarm signal, which can further avoid false alarms caused by detection errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It 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 The signal filtering circuit diagram of the present invention;

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

[0043] Figure 6 It is the circuit diagram of the single chip microcomputer of the present invention. DETAILED DESCRIPTION

[0044] The following will be combined with the accompanying drawings in the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] In the power supply and distribution system, electric energy is transmitted by conductors such as cables and copper busbars. The insulation layer between conductors is often damaged or aged, resulting in poor insulation and arcing between conductors and between conductors and ground. This arcing further leads to poor conductors, forming a vicious cycle. In severe cases, it can cause fires and explosions, causing significant losses to the entire power supply system and posing a serious threat to personnel safety.

[0046] The existing arc detection solutions on the market are residual current detection method and fault arc detection method.

[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 an arc between the conductor and the ground.

[0048] Fault arc detection: The circuit voltage and current changes are monitored to determine whether the conductor is arcing. This solution is currently used at the end of the distribution network, but it is prone to false alarms and its effectiveness is controversial. It is currently not used in the primary and secondary distribution networks with higher power due to the large power and diversity of the subsequent loads.

[0049] In order to be able to be used in all power distribution circuits, even in the case of large loads and load diversity, the arcing between conductor lines and between lines and ground can be detected quickly and accurately.

[0050] See also Figure 1 As shown, the purpose of this embodiment is to provide an arc current detection circuit based on a current sensor for 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 operation comparison circuit, a single-chip 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 operation comparison circuit or the single-chip circuit through the transmission medium, and the operation comparison circuit or the single-chip circuit is connected to the automatic counting alarm circuit;

[0051] The arc signal acquisition circuit is used to collect the current at both ends of the conductor through electromagnetic or current cancellation to obtain the arc current signal. The arc current signal is rectified, amplified and filtered by the signal filter circuit and then output to the operation comparison circuit or the single-chip computer circuit. When the number of arc fault signals output by the operation comparison circuit or the single-chip computer circuit within 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 the present invention is to detect, calculate and compare the arc current by detecting the difference between the currents at the two ends of the same conductor. All arc current detection methods using the principle of the present invention are within the scope of this patent.

[0053] In the present invention, conductor refers to a conductive material used to transmit electrical energy.

[0054] Arc signal acquisition circuit: a device for collecting the current at the position, including but not limited to a transformer, a Hall sensor, a shunt, a transmitter and all other devices for collecting current. In this embodiment, a current transformer is used as an example for explanation. Figure 2 As shown, the arc signal acquisition circuit includes current transformers CT1, CT2, CT3 and sampling resistors, wherein:

[0055] The current transformers CT1 and CT2 are installed at the head and tail ends of the conductor respectively, and the secondary sides of the current transformers CT1 and CT2 pass through the current transformer CT3 in the opposite direction, that is, the secondary currents of CT1 and CT2 pass through the current transformer CT3 in the opposite direction;

[0056] The current transformer CT3 is connected to a sampling resistor, and the sampling resistor is 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 pass 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, cancel each other out, and the output is basically 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 cannot cancel each other out, and the output is basically a differential current signal; this signal is amplified and rectified by the post-stage circuit and then output to the single-chip microcomputer circuit or outputs an alarm signal after post-stage comparison.

[0058] The above is a circuit connection method of the current transformer, that is, the secondary currents of the two current transformers pass through another current transformer, and the magnetic field generated in the same current transformer is compared to obtain the arc 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 respectively installed at the head and tail ends of the conductor, and the secondary outputs of current transformers CT1 and CT2 are reversely connected to sampling resistors, that is, the secondary currents of current transformers CT1 and CT2 flow reversely through the sampling resistors, and the sampling resistors are connected to the signal filtering circuit.

[0060] The outputs of the two current sensors are reversed and output to a resistor at the same time. At this time, the currents I1 and I2 passing through the resistor are in opposite directions. Under normal circumstances, I1=I2, and the currents on the resistor are in opposite directions and equal in magnitude, cancel each other out, and the output is 0; when there is an arc I3 on ​​the conductor, I1=I2+I3, and I1>I2 at this time. At this time, the currents I1 and I2 passing through the resistor are in opposite directions and cannot cancel each other out, and a difference current signal is output; this signal is amplified and rectified by the subsequent stage and then output to the single-chip microcomputer circuit or output as an alarm signal after comparison by the subsequent stage.

[0061] That is, the secondary sides of the two current transformers are connected in reverse parallel, the currents are output to the same sampling resistor, the currents are compared, and the arc 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 by the arcing signal acquisition circuit is output to the sampling resistor to obtain the arcing voltage signal;

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

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

[0066] The anode of diode D3 is connected to pin 1 of operational amplifier U1-1, and the cathode of diode D3 is connected to pin 2 of operational amplifier U1-1;

[0067] The cathode of diode D4 is connected to pin 1 of operational amplifier U1-1, the anode 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 connected to one end of resistor R4, and the other end of resistor R4 is connected to the upper end of resistor R1;

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

[0071] 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;

[0072] One end of the resistor R9 is connected to the 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 outputs to the signal comparison circuit through the transmission medium.

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

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

[0075] Key Features

[0076] Low offset voltage: 25μV maximum

[0077] Zero drift: 0.03μV / ℃

[0078] Low Noise: 8.8nV / √Hz (0.25μVPP from 0.1Hz to 10Hz)

[0079] Excellent DC precision: 142dB PSRR and 146dB CMRR

[0080] High gain bandwidth: 2MHz

[0081] Quiescent current: 475μA maximum

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

[0083] The signal current comparison circuit outputs the comparison result, which can be used for local display and control independently, or uploaded to the monitoring background through the network to realize network monitoring, control and protection. The current signal collected at both ends of the conductor can also be amplified and then compared to obtain the arc current value signal. The core is to collect the current at both ends of the conductor for comparison, so as to collect the size of the arc current. All arc current detection using the arc detection principle of the present invention belongs to the scope of this patent.

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

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

[0086] The arc 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 comparison value of the arc current signal can be adjusted by adjusting the resistor R10 for resistance division. When the arc current signal voltage exceeds the comparison value, pin 7 of the operational amplifier U2-1 outputs an arc fault signal to the automatic counting alarm circuit.

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

[0088] like Figure 6 As shown, the single-chip microcomputer circuit includes a single-chip microcomputer U3,

[0089] The collected arc current signals of multiple conductors are 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 single-chip computer U3 for analog-to-digital conversion. When the input arc current signal is greater than the set value, the digital output terminals 8, 9, 10, 11, 12, 13, 18 and 19 of the single-chip computer U3 output arc fault signals to the automatic counting alarm circuit.

[0090] Pins 5 and 7 of the single-chip computer U3 transmit arc current and alarm signals to other devices or monitoring platforms through the subsequent communication interface circuits such as RS485, CAN, 4G modules, etc.

[0091] The arc current value and alarm signal are output as communication signals through pins 5 and 7 of the single-chip microcomputer U3, and the signal can be transmitted to the management platform through the communication interface circuit and network.

[0092] The single chip microcomputer U3 is preferably a STC12C5A08AD-35I-LQFP44 single chip microcomputer.

[0093] In addition, in order to prevent false alarms, an automatic counting alarm circuit is provided in the present invention, which includes a counter circuit and an alarm connected to the counter circuit. The operation comparison circuit or the single-chip microcomputer 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 operation comparison circuit or the single-chip microcomputer circuit. When the number of arc fault signals input by the operation comparison circuit or the single-chip microcomputer circuit per 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 alarm signals in the form of sound, light, signal contacts, voltage, etc., thereby avoiding false alarms.

[0094] The present invention adopts a method of installing two current transformers at both ends of the conductor, passing the secondary currents of the two current transformers through a third current transformer, and generating a magnetic field in the third current transformer for comparison to obtain an arc current signal, or directly outputting the currents collected by the two transformers to a common resistor for comparison, or comparing through a comparator circuit and some other amplifying circuits to obtain the arc current of the conductor; after the arc current signal is amplified and rectified, it is processed and output by an operation comparison circuit or a single-chip microcomputer circuit to obtain an arc fault signal, and when the number of arc fault current signals output by the operation comparison circuit or the single-chip microcomputer circuit within a unit time reaches the number set by the automatic counting alarm circuit, the automatic counting alarm circuit outputs an alarm signal, and at the same time, the communication interface 5 and 7 pins of the single-chip microcomputer U3 transmit the arc current and the alarm signal to other devices or monitoring platforms to the communication interface circuits of the subsequent stages such as RS485, CAN, 4G modules, etc.;

[0095] The currents collected by two current transformers on a conductor are compared and processed to obtain the size of the arcing current or the comparison signal of the current to determine whether the conductor is arcing. It is particularly suitable for use in the power distribution circuit of the power supply and distribution system. Even in the case of large loads and load diversity, it can quickly and accurately detect the arcing between conductor lines and between lines and ground. In addition, by setting the number of arcing fault current signals output per unit time to reach the set number, the automatic counting alarm circuit will output an alarm signal, which can further avoid false alarms caused by detection errors.

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

[0097] The invention has low cost and can detect the arcing defect of the conductor in a relatively short time regardless of the load size and load diversity.

[0098] The above shows and describes 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 by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. The arc current detection circuit based on the current sensor for comparison is characterized by: It includes a signal acquisition circuit, a transmission medium and a signal comparison circuit, wherein the signal acquisition circuit includes an arcing signal acquisition circuit and a signal filtering circuit, the signal comparison circuit includes an operation comparison circuit, a single-chip 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 operation comparison circuit or the single-chip circuit through the transmission medium, and the operation comparison circuit or the single-chip circuit is connected to the automatic counting alarm circuit; The arcing signal acquisition circuit is used to collect the current at both ends of the conductor through electromagnetic or current cancellation to obtain an arcing current signal, and the arcing current signal is rectified, amplified and filtered by the signal filtering circuit and then output to the operation comparison circuit or the single-chip circuit. When the number of arcing fault signals output by the operation comparison circuit or the single-chip circuit within a unit time reaches the number set by the automatic counting alarm circuit, the automatic counting alarm circuit outputs an alarm signal; The arc signal acquisition circuit includes current transformers CT1, CT2, CT3 and sampling resistors, wherein: The current transformers CT1 and CT2 are respectively installed at the head and tail ends of the conductor, and the secondary sides of the current transformers CT1 and CT2 respectively pass through the current transformer CT3 in the reverse direction; The current transformer CT3 is connected to the sampling resistor, and the sampling resistor is connected to the signal filtering circuit.

2. The arc current detection circuit based on current sensor comparison according to claim 1, characterized in that: The current transformers CT1 and CT2 are respectively installed at the head and tail ends of the conductor, and the secondary outputs of the current transformers CT1 and CT2 are both connected to the sampling resistor in parallel, and the sampling resistor is connected to the signal filtering circuit.

3. The arc 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 circuits, wherein: The peripheral circuit includes diodes D1, D2, D3, D4, resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, capacitors C1, C2, and the diodes D1 and D2 are connected in reverse parallel; The arc voltage signal is input to the pin 2 of the operational amplifier U1-1 through the resistor R2, and the pin 3 of the operational amplifier U1-1 is grounded; The anode of the diode D3 is connected to the pin 1 of the operational amplifier U1-1, and the cathode of the diode D3 is connected to the pin 2 of the operational amplifier U1-1; The cathode of the diode D4 is connected to the pin 1 of the operational amplifier U1-1, the anode of the diode D4 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to the pin 6 of the operational amplifier U1-2 and to one end of the resistor R4, and the other end of the resistor R4 is connected to the upper end of the resistor R1; The resistor R6 is connected in parallel with the capacitor C1 and then connected to the pins 6 and 7 of the operational amplifier U1-2; Pin 7 of the operational amplifier U1-2 is connected to pin 3 of the 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 the 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 outputs the signal to the signal comparison circuit through the transmission medium.

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

5. The arc current detection circuit based on current sensor comparison according to claim 4, characterized in that: The single-chip circuit includes a single-chip microcomputer U3, The arc current signal is rectified, amplified and filtered by the signal filter circuit, and then connected to the analog input channels of pins 40, 41, 42, 43, 44, 1, 2 and 3 of the single-chip microcomputer U3 respectively. The digital output terminals 8, 9, 10, 11, 12, 13, 18 and 19 of the single-chip microcomputer U3 output arc fault signals to the automatic counting alarm circuit; Pins 5 and 7 of the single-chip microcomputer U3 transmit arc current and alarm signal to other equipment or monitoring platform through the subsequent communication interface circuit.

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

7. The arc current detection circuit based on current sensor comparison according to claim 1, characterized in that: The transmission medium transmits the power parameters by means of wires, optical fibers, wireless signals, and mobile network signals.

8. The arc current detection circuit based on current sensor comparison according to claim 3, characterized in that: 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.

9. The arc current detection circuit based on current sensor comparison according to claim 4, characterized in that: The operational amplifier U2-2 is a LM358 chip.

10. The arc current detection circuit based on current sensor comparison according to claim 5, characterized in that: The single chip microcomputer U3 is a STC12C5A08AD-35I-LQFP44 single chip microcomputer.

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