CN114325266B - Device for detecting and positioning fault arc in commercial power environment and working method thereof - Google Patents

Abstract

The invention discloses a device for detecting and locating a fault arc in a mains power environment, comprising a high-speed AD acquisition module, a low-speed AD acquisition module, an isolation module, a signal conditioning module, a current transformer module, a switch module, a DA output module, Screen display module, arc fault location analysis module, arc fault detection and analysis module, fusion analysis module, and arc fault generation module, DA output module is used to generate detection signals and send the detection signals to arc fault generation modules, arc fault generation modules It is used to generate a fault arc and generate a reflected signal when the detection signal encounters a fault arc. The high-speed AD acquisition module is used to obtain the detection signal generated by the DA output module and the reflected signal generated by the fault arc generation module. The invention can solve the technical problem that the existing arc fault detection device can only detect the fault arc, but cannot simultaneously realize the detection and location of the fault arc and the type detection of the fault arc.

Description

Device and working method for arc fault detection and location in mains environment

technical field

The invention belongs to the technical field of electrical fire safety, and more specifically relates to a device for detecting and locating a fault arc in a commercial power environment and a working method thereof.

Background technique

With the improvement of the application level of electric energy in society, the types of household electrical equipment have gradually increased, the electricity consumption of residents has increased sharply, and electrical fire accidents have occurred frequently, so that the safety of electricity consumption in low-voltage lines has attracted much attention. Arc fault is one of the important causes of electrical fires under low-voltage lines. Detection and location of arc faults are of great significance to avoid the occurrence of electrical fires in households.

However, there are some technical problems that cannot be ignored in the existing arc fault detection device: first, the existing arc fault detection device can only detect the fault arc, but cannot simultaneously realize the detection and location of the fault arc and the type detection of the fault arc; 2. The detection accuracy rate of the existing arc fault detection device is low; 3. Since most of today's household power lines are buried in the wall, when the existing fault arc detection device detects the fault arc, it cannot realize accurate fault detection. The location of the arc will lead to the inability to eliminate the fault in time, which will cause a very large hidden danger to the safety of household electricity.

Contents of the invention

Aiming at the above defects or improvement needs of the prior art, the present invention provides a device for detecting and locating arc faults in the mains environment and its working method. The purpose is to solve the problem that the existing arc fault detection devices can only perform fault arc detection, but cannot realize the technical problems of fault arc detection and location and fault arc type detection at the same time, and the technical problem of low accuracy rate of fault arc detection, and when the fault arc is detected, it cannot realize accurate fault arc location, thus Lead to technical problems that cannot be eliminated in time and cause great hidden dangers to the safety of household electricity use.

In order to achieve the above object, according to one aspect of the present invention, a device for detecting and locating arc faults in a mains environment is provided, including a high-speed AD acquisition module, a low-speed AD acquisition module, an isolation module, a signal conditioning module, and a current mutual inductance module. device module, switch module, DA output module, screen display module, fault arc location analysis module, fault arc detection and analysis module, fusion analysis module, and fault arc generation module, characterized in that,

The DA output module is used to generate a detection signal and send the detection signal to the fault arc generation module;

The fault arc generation module is used to generate a fault arc, and generate a reflected signal when the detection signal encounters a fault arc;

The high-speed AD acquisition module is used to obtain the detection signal generated by the DA output module and the reflected signal generated by the fault arc generation module;

The low-speed AD module is used to collect the current signal flowing through the fault arc generation module;

The isolation module is connected to the external AC signal, and is used to isolate the AC power in the external AC signal, so that the detection signal collected by the high-speed AD acquisition module passes through unimpeded, and the detection signal generated by the DA output module passes through unimpeded;

The current transformer module is used to convert the large current in the external AC signal into a small current, and transmit the converted external AC signal to the signal conditioning module.

The signal conditioning module is used to convert the current signal in the converted external AC signal into a voltage signal.

The fault arc location analysis module is used to control the DA output module to generate detection signals, and according to the detection signals and reflection signals collected by the high-speed AD acquisition module, the cross-correlation algorithm is used to calculate the distance of the fault arc and the type of fault arc, and store them in The fault arc is located in the first ring buffer area of the ring queue;

The arc fault detection analysis is used to process the current signal collected by the low-speed AD acquisition module. The distortion rate of the current signal is calculated by the Pearson coefficient and stored in the second ring buffer area of the arc fault detection ring queue.

The fusion analysis module is used to fuse the distance and type of fault arc obtained by the fault arc location analysis module and the distortion rate of the current signal obtained by the fault arc detection and analysis module to judge whether there is a fault arc, and When it is judged that there is an arc fault, the control screen display module displays warning information, the relay switch of the control switch module is disconnected, and the screen display module is notified to output the distance of the fault arc and the type of fault arc.

Preferably, the isolation module includes a coupling transformer, a withstand voltage capacitor C, and a transient suppression diode.

Preferably, the two input terminals of the coupling transformer are directly connected to the signal input terminals;

One end of the output of the coupling transformer is connected to the power line through a withstand voltage capacitor, and the other end of the output is directly connected to the power line;

The two output terminals of the coupling transformer are connected with transient suppression diodes.

Preferably, the signal conditioning module includes a first operational amplifier, a second operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a potentiometer, and a first capacitor.

Preferably, one end of the first resistor is connected to one end of the second resistor and the AC signal input end, and the other end is directly connected to the signal input ground end;

One end of the first capacitor is connected to the other end of the second resistor and the signal positive input end of the first operational amplifier, and the other end is connected to the signal input ground end;

One end of the third resistor is connected to the signal inverting input end of the first operational amplifier and the signal output end of the first operational amplifier, and the other end is connected to the signal positive input end of the second operational amplifier;

One end of the fourth resistor is connected to the signal inverting input end of the second operational amplifier and the potentiometer, and the other end is connected to the ground end.

The other end of the potentiometer is connected to the signal output end of the second operational amplifier.

According to another aspect of the present invention, there is provided a working method of the device for arc fault detection and location in the above-mentioned commercial power environment, comprising the following steps:

(1) The DA output module outputs a detection signal, and transmits the emission signal to the fault arc generation module through the isolation module 3;

(2) The fault arc generation module generates a fault arc, and generates a reflected signal when the detection signal encounters a fault arc;

(3) The low-speed AD acquisition module collects the current signal flowing through the fault arc generation module through the current transformer module and the signal conditioning module, and transmits the current signal to the fault arc detection and analysis module.

(4) High-speed AD acquisition module 1 collects the detection signal from the DA output module and the reflected signal from the fault arc generation module through the isolation module;

(5) The fault arc location analysis module uses a cross-correlation algorithm to process the detection signal and reflection signal collected by the high-speed AD acquisition module to obtain the distance data D of the fault arc and the type data Ty of the fault arc;

(6) The arc fault location analysis module stores the distance data D of the arc fault and the type data Ty of the arc fault in the first ring buffer area of the arc fault location ring queue.

(7) The fault arc detection and analysis module uses the Pearson coefficient algorithm to process the current signal flowing through the fault arc generation module to obtain the distortion rate Dr of the current signal.

(8) The arc fault detection analysis module stores the distortion rate Dr in the second ring buffer area of the arc fault detection ring queue;

(9) The fusion analysis module judges whether the total number of data in the first ring buffer area and the second ring buffer area is equal to W, if so, then enter step (10), otherwise return to step (1).

(10) The fusion analysis module reads W pieces of data in the first ring buffer area of the fault arc location ring queue, the data includes the distance data D of the fault arc and the data Ty of the fault arc type.

(11) The fusion analysis module preprocesses the W data in the first circular buffer area, retains the data between the distance of 0 and the length of the wire in the distance data of the fault arc, and filters out the rest of the distance data.

(12) The fusion analysis module calculates the average value and divergence DI of the distance data retained in step (11).

(13) The fusion analysis module reads W pieces of current distortion rate data in the second ring buffer area of the fault arc detection ring queue.

(14) fusion analysis module counts the number T of data whose distortion rate exceeds a threshold value in the data of the second ring buffer area;

(15) The fusion analysis module judges whether the value of T is greater than or equal to Q1, if yes, it indicates that there is a fault arc, and then enters step (16), otherwise enters step (17).

(16) The fusion analysis module controls the screen display module to display warning information, controls the relay switch of the switch module to disconnect, and controls the screen display module to display the average value A of the distance of the fault arc and the type Ty of the fault arc, and the process ends.

(17) The fusion analysis module judges whether the distance divergence DI of the fault arc is greater than or equal to the distance divergence threshold TH, if yes, it indicates that there is a fault arc, and then returns to step (16), otherwise, proceeds to step (18).

(18) The fusion analysis module judges whether the data number T of the current distortion rate is less than or equal to Q2, if yes, it means that there is no fault arc, and then turns to step (19), otherwise the process ends.

(19) The fusion analysis module clears the system alarm, controls the relay switch of the switch module to close, and controls the screen display module to display that there is no fault arc, and the process ends.

Generally speaking, compared with the prior art, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

1. Because the device of the present invention adopts the arc fusion sensing technology, it can not only detect the fault arc but also locate the fault arc, so it can solve the problem that the existing arc fault detection device can only detect the fault arc, but cannot realize the fault arc detection at the same time Technical issues related to location and fault arc type detection, that is, this device can not only realize fault arc detection and location functions, but also detect the type of fault arc (series arc or parallel arc);

2. Since the device of the present invention adopts the fusion analysis method, it can not only realize the fault arc detection and positioning function, but also can solve the technical problem of low detection accuracy of the existing arc fault detection device;

3. Because the device of the present invention adopts the fusion analysis method, it realizes the detection of arc fault with high accuracy and low false alarm rate, and the location of arc fault with high accuracy, so it can solve the problem that the existing arc fault detection device cannot realize. Fault arc location, resulting in technical problems that cannot be eliminated in time and cause great hidden dangers to household electricity safety;

4, the method of the present invention is owing to have adopted step (1) and step (5), and it uses cross-correlation algorithm, therefore can solve the technical problem of fault arc location and detection fault arc type;

5. The method of the present invention is used to adopt step (3) and step (7), which uses the Pearson coefficient algorithm, so it can solve the technical problem of detecting fault arc

Description of drawings

Fig. 1 is a block diagram of the system composition of the device for arc fault detection and location under the mains power environment of the present invention;

Fig. 2 is the specific flowchart of the working method of the device for arc fault detection and location under the mains environment of the present invention;

Fig. 3 is the specific circuit diagram of isolation module in the device of the present invention;

Fig. 4 is a specific circuit diagram of the signal conditioning module in the device of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

As shown in Fig. 1, the present invention provides a kind of device that is used for arc fault detection and location in the mains environment, including high-speed analog-digital (Analog-digital, referred to as AD) acquisition module 1, low-speed AD acquisition module 2, isolation module 3. Signal conditioning module 4, current transformer module 5, switch module 6, digital-analog (DA) output module 7, screen display module 8, fault arc location analysis module 9, fault arc detection and analysis module 10, Fusion analysis module 11, and arc fault generation module 12.

In the present invention, the model of the high-speed AD acquisition module 1 is ACM9226, the model of the low-speed AD acquisition module 2 is ADC128S022, the model of the DA output module 7 is ACM9767, and the model of the current transformer module 5 is ZMCT103C.

The digital-analog (DA) output module 7 is used to generate a detection signal and send the detection signal to the fault arc generation module 12 .

The fault arc generating module 12 is used to generate a fault arc, and generate a reflected signal when the detection signal encounters a fault arc.

The high-speed AD acquisition module 1 is used to acquire the detection signal generated by the DA output module 7 and the reflected signal generated by the fault arc generation module 12 , and the low-speed AD module 2 is used to collect the current signal flowing through the fault arc generation module 12 .

The isolation module 3 is connected to an external AC signal of 220V, 50HZ, and is used to isolate the AC power in the external AC signal, so that the detection signal generated by the DA output module 7 collected by the high-speed AD acquisition module 1 passes through without hindrance, and makes the DA output module 7 The generated detection signal passes through unimpeded.

As shown in Figure 3, the isolation module 3 includes a coupling transformer T11, a withstand voltage capacitor C12, and a transient suppression diode D13; the two input terminals of the coupling transformer T11 are directly connected to the signal input terminal IN, and one end of the output of the coupling transformer T11 is passed through the withstand voltage The piezoelectric capacitor C12 is connected to the power line, and the other end of the output is directly connected to the power line; the two output ends of the coupling transformer T11 are connected to the transient suppression diode D13.

The current transformer module 5 is used to convert the large current in the external AC signal into a small current, and transmit the converted external AC signal to the signal conditioning module 4 .

The signal conditioning module 4 is used to convert the current signal in the converted external AC signal into a voltage signal.

As shown in Figure 4, the signal conditioning module 4 includes a first operational amplifier U21, a second operational amplifier U22, a first resistor R23, a second resistor R24, a third resistor R25, a fourth resistor R26, a potentiometer R27, and a first Capacitor C28. One end of the first resistor R23 is connected to one end of the second resistor R24 and the AC signal input end, and the other end is directly connected to the signal input ground end; one end of the first capacitor C28 is connected to the other end of the second resistor R24, and the first calculation The signal of the amplifier U21 is connected to the positive input terminal, and the other end is connected to the signal input ground terminal; one end of the third resistor R25 is connected to the signal inverting input terminal of the first operational amplifier U21 and the signal output terminal of U21, and the other end is connected to The signal positive input terminal of the second operational amplifier U22; one end of the fourth resistor R26 is connected with the signal inverting input terminal of the second operational amplifier U22 and the potentiometer R27, and the other end is connected to the ground terminal; the other end of the potentiometer R27 Connect to the signal output terminal of the second operational amplifier U22.

The fault arc location analysis module 9 is used to control the DA output module 7 to generate a detection signal, and according to the detection signal and reflection signal collected by the high-speed AD acquisition module 1, the cross-correlation algorithm is used to calculate the distance of the fault arc and the type of the fault arc, and It is stored in the first ring buffer area (Ring Buffer1) of the fault arc location ring queue.

Arc fault detection and analysis 10 is used to process the current signal collected by the low-speed AD acquisition module 2, calculate the distortion rate of the current signal through the Pearson coefficient, and store it in the second ring buffer area (Ring Buffer2) of the arc fault detection ring queue .

The fusion analysis module 11 is used to perform data fusion on the distance of the arc fault and the type of the arc fault obtained by the arc fault location analysis module 9, and the distortion rate of the current signal obtained by the arc fault detection analysis module 10, so as to determine whether there is an arc fault Generated, and when it is judged that there is a fault arc, the control screen display module 8 displays a warning message, the relay switch of the control switch module 6 is disconnected, and the screen display module 8 is notified to output the distance of the fault arc and the type of fault arc.

As shown in Figure 2, the present invention also provides a working method for the device for arc fault detection and location in the above-mentioned commercial power environment, including the following steps:

(1) The DA output module 7 outputs a detection signal, and transmits the emission signal to the fault arc generation module 12 through the isolation module 3;

(2) The fault arc generation module 12 generates a fault arc, and generates a reflected signal when the detection signal encounters a fault arc;

(3) The low-speed AD acquisition module 2 collects the current signal flowing through the arc fault generation module 12 through the current transformer module 5 and the signal conditioning module 4 , and transmits the current signal to the arc fault detection and analysis module 10 .

(4) the high-speed AD acquisition module 1 collects the detection signal from the DA output module 7 and the reflected signal from the fault arc generation module 12 through the isolation module 3;

(5) The fault arc location analysis module 9 uses a cross-correlation algorithm to process the detection signal and reflection signal collected by the high-speed AD acquisition module 1 to obtain the distance data D of the fault arc and the type data Ty of the fault arc (ie, series arc or parallel arc) ;

(6) arc fault location analysis module 9 stores the distance data D and the arc fault type data Ty of the arc fault in the first ring buffer area (Ring Buffer1) of the arc fault location ring formation, and in the first ring buffer area (RingBuffer1) The data will be read by the fusion analysis module.

(7) The arc fault detection and analysis module 10 uses the Pearson coefficient algorithm to process the current signal flowing through the arc fault generation module 12 to obtain the distortion rate Dr of the current signal.

(8) The arc fault detection analysis module 10 stores the distortion rate Dr in the second ring buffer area (Ring Buffer2) of the arc fault detection ring queue, and the data in the second ring buffer area (Ring Buffer2) will be read by the fusion analysis module Pick.

(9) Fusion analysis module 11 judges whether the total number of data in the first ring buffer area and the second ring buffer area is equal to W, if so, then enter step (10), otherwise return to step (1).

Specifically, the value range of W is between 30 and 100, preferably equal to 50 (that is, 50 data per second).

(10) The fusion analysis module 11 reads W data in the first ring buffer area (RingBuffer1) of the arc fault location ring queue, the data includes the distance data D of the arc fault and the type data Ty of the arc fault.

(11) The fusion analysis module 11 preprocesses the W data in the first ring buffer area (Ring Buffer1), retains the data between 0 and the length of the wire in the distance data of the fault arc, and filters out the rest distance data.

(12) The fusion analysis module 11 calculates the average value and divergence DI of the distance data retained in step (11).

(13) The fusion analysis module 11 reads W pieces of current distortion rate data in the second ring buffer area (RingBuffer2) of the arc fault detection ring queue.

(14) fusion analysis module 11 counts the number T of data whose distortion rate exceeds the threshold in the data of the second ring buffer area (Ring Buffer2);

(15) The fusion analysis module 11 judges whether the value of T is greater than or equal to Q1, if yes, it indicates that there is an arc fault, and then enters step (16), otherwise enters step (17).

Specifically, the value of Q1 is between 10 and 20, preferably 14.

(16) Fusion analysis module 11 controls screen display module 8 to display warning information, and the relay switch of control switch module 6 is disconnected, and controls screen display module 8 to display the average value A of the distance of fault arc and the type Ty of fault arc, and the process ends .

(17) The fusion analysis module 11 judges whether the distance divergence DI of the fault arc is greater than or equal to the distance divergence threshold TH, if yes, it indicates that there is a fault arc, and then returns to step (16), otherwise proceeds to step (18).

Specifically, the value range of the distance divergence threshold TH is 0.6 to 1.0, preferably 0.8.

(18) The fusion analysis module 11 judges whether the data number T of the current distortion rate is less than or equal to Q2, if yes, it means that there is no arc fault, and then proceeds to step (19), otherwise the process ends.

Specifically, the value range of Q2 is between 5 and 15, preferably 9.

(19) The fusion analysis module 11 clears the system alarm, controls the relay switch of the switch module 6 to close, and controls the screen display module 8 to display that there is no fault arc, and the process ends.

It is easy for those skilled in the art to understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, All should be included within the protection scope of the present invention.

Claims (5)

1. the working method of the device that is used for fault arc detection and location under a city power environment, the device that is used for fault arc detection and location under the city power environment includes a high-speed AD acquisition module, a low-speed AD acquisition module, an isolation module, Signal conditioning module, current transformer module, switch module, DA output module, screen display module, fault arc location analysis module, fault arc detection and analysis module, fusion analysis module, and fault arc generation module, DA output module is used to generate detection signals , and send the detection signal to the fault arc generation module, the fault arc generation module is used to generate a fault arc, and generate a reflected signal when the detection signal encounters a fault arc, and the high-speed AD acquisition module is used to obtain the detection signal generated by the DA output module and The reflected signal generated by the fault arc generation module, the low-speed AD module is used to collect the current signal flowing through the fault arc generation module, and the isolation module is connected to the external AC signal to isolate the AC power in the external AC signal, so that the high-speed AD acquisition module The collected detection signal passes through unimpeded, and makes the detection signal generated by the DA output module pass through unimpeded. The current transformer module is used to convert the large current in the external AC signal into a small current, and transmit the converted external AC signal To the signal conditioning module, the signal conditioning module is used to convert the current signal in the converted external AC signal into a voltage signal, the fault arc location analysis module is used to control the DA output module to generate a detection signal, and according to the detection signal collected by the high-speed AD acquisition module The signal and reflected signal, using the cross-correlation algorithm to calculate the distance of the fault arc and the type of the fault arc, and store it in the first ring buffer area of the fault arc location ring queue, and the fault arc detection analysis is used to process the acquisition of the low-speed AD acquisition module The current signal, the distortion rate of the current signal is obtained by calculating the Pearson coefficient, and stored in the second ring buffer area of the fault arc detection ring queue, and the fusion analysis module is used to calculate the distance of the fault arc obtained by the fault arc location analysis module And the type of fault arc, and the distortion rate of the current signal obtained by the fault arc detection and analysis module are used for data fusion to judge whether there is a fault arc, and when it is judged that there is a fault arc, the control screen display module displays warning information and controls the switch The relay switch of the module is disconnected, and the screen display module is notified to output the distance of the fault arc and the type of the fault arc. It is characterized in that the working method includes the following steps: (1) The DA output module outputs a detection signal, and transmits the detection signal to the fault arc generation module through the isolation module; (2) The fault arc generation module generates a fault arc, and generates a reflected signal when the detection signal encounters a fault arc; (3) The low-speed AD acquisition module collects the current signal flowing through the fault arc generation module through the current transformer module and the signal conditioning module, and transmits the current signal to the fault arc detection and analysis module; (4) The high-speed AD acquisition module collects the detection signal from the DA output module and the reflected signal from the fault arc generation module through the isolation module; (5) The fault arc location analysis module uses a cross-correlation algorithm to process the detection signal and reflection signal collected by the high-speed AD acquisition module to obtain the distance data D of the fault arc and the type data Ty of the fault arc; (6) The fault arc location analysis module stores the distance data D of the fault arc and the type data Ty of the fault arc in the first ring buffer area of the fault arc location ring queue; (7) The fault arc detection and analysis module uses the Pearson coefficient algorithm to process the current signal flowing through the fault arc generation module to obtain the distortion rate Dr of the current signal; (8) The arc fault detection analysis module stores the distortion rate Dr in the second ring buffer area of the arc fault detection ring queue; (9) fusion analysis module judges whether the total number of data in the first ring buffer area and the second ring buffer area is equal to W, if then enter step (10), otherwise return to step (1); (10) the fusion analysis module reads the W data in the first ring buffer area of the fault arc location ring queue, and the data includes the distance data D and the fault arc type data Ty of the fault arc; (11) the fusion analysis module preprocesses the W data in the first circular buffer area, and keeps the data between 0 and the length of the wire in the distance data of the fault arc, and filters out the rest of the distance data; (12) the average value and the divergence DI of the distance data retained in the fusion analysis module calculation step (11); (13) The fusion analysis module reads the W current distortion rate data in the second ring buffer area of the arc fault detection ring queue; (14) fusion analysis module counts the number T of data whose distortion rate exceeds a threshold value in the data of the second ring buffer area; (15) fusion analysis module judges whether the value of T is greater than or equal to Q1, if then explain that there is fault arc, then enter step (16), otherwise enter step (17); (16) The fusion analysis module controls the screen display module to display warning information, the relay switch of the control switch module is disconnected, and the control screen display module displays the average value A of the distance of the fault arc and the type Ty of the fault arc, and the process ends; (17) Fusion analysis module judges whether the distance divergence DI of fault arc is greater than or equal to the distance divergence threshold TH, if yes then shows that there is fault arc, then returns to step (16), otherwise proceeds to step (18); (18) Fusion analysis module judges whether the data number T of current distortion rate is less than or equal to Q2, if then explain that there is no arc fault, then go to step (19), otherwise the process ends; (19) The fusion analysis module clears the system alarm, controls the relay switch of the switch module to close, and controls the screen display module to display that there is no fault arc, and the process ends. 2. The working method of the device for arc fault detection and location under the mains power environment according to claim 1, wherein the isolation module includes a coupling transformer, a withstand voltage capacitor C, and a transient suppression diode. 3. the working method of the device that is used for fault arc detection and location under the mains power environment according to claim 2, is characterized in that, The two input ends of the coupling transformer are directly connected to the signal input end; One end of the output of the coupling transformer is connected to the power line through a withstand voltage capacitor, and the other end of the output is directly connected to the power line; The two output terminals of the coupling transformer are connected with transient suppression diodes. 4. The working method of the device for fault arc detection and location under the mains power environment according to claim 3, wherein the signal conditioning module comprises a first operational amplifier, a second operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a potentiometer, and a first capacitor. 5. the working method of the device that is used for fault arc detection and location under the mains power environment according to claim 4, is characterized in that, One end of the first resistor is connected to one end of the second resistor and the AC signal input end, and the other end is directly connected to the signal input ground end; One end of the first capacitor is connected to the other end of the second resistor and the signal positive input end of the first operational amplifier, and the other end is connected to the signal input ground end; One end of the third resistor is connected to the signal inverting input end of the first operational amplifier and the signal output end of the first operational amplifier, and the other end is connected to the signal positive input end of the second operational amplifier; One end of the fourth resistor is connected to the signal inverting input end of the second operational amplifier and the potentiometer, and the other end is connected to the ground end; The other end of the potentiometer is connected to the signal output end of the second operational amplifier.

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