Switching resistance state identification method and system based on optical fiber sensing

Abstract

The present application relates to the closing resistance state recognition technical field, specifically relates to a closing resistance state identification method and system based on optical fiber sensing, including light source module, circulator, sensing optical fiber connector, optical amplifier, one-to-two coupler, second optical filter, first optical filter, two-in-one coupler, photoelectric converter, analog-digital conversion circuit, microprocessor and server, the optical amplifier amplifies the input light source of the circulator, and the amplified light is output from the output port, the first optical filter filters the rising edge of specific wavelength light, the microprocessor receives the output data of the analog-digital conversion circuit, controls the working mode of the light source module, and sends the operation result to the server, the system can accurately collect the closing resistance correlation parameters, accurately judge the closing resistance operating state, can give the judgment whether the closing resistance can carry out the next action, and can give the position of the closing resistance discharge.

Description

Technical Field

[0001] This invention relates to the field of closing resistor status identification technology, and in particular to a method and system for identifying closing resistor status based on fiber optic sensing. Background Technology

[0002] The closing resistor is a very important component of a circuit breaker. It is necessary to evaluate the condition of the closing resistor to ensure its safe operation when opening and closing.

[0003] Currently, patent CN118169553A discloses a device and method for diagnosing the closing resistance status of a high-voltage circuit breaker. The device includes a differential pressure acquisition module for acquiring the differential pressure across the main circuit of the high-voltage circuit breaker when the closing resistor is engaged; a current acquisition module for acquiring the closing current of the main circuit of the high-voltage circuit breaker; and a high-voltage circuit breaker intelligent diagnosis module for obtaining the closing resistor engagement time, duration, and dynamic waveform of the resistance within the duration period based on the differential pressure and current values, and then diagnosing the closing resistance status accordingly. This invention utilizes a distributed monitoring device to synchronously acquire the main circuit current waveform and the voltage waveform across the main circuit of the high-voltage circuit breaker, providing data support for fault diagnosis under circuit breaker operating conditions; automatically calculating the circuit breaker closing resistance, closing resistance engagement time, and duration, achieving intelligent detection of the high-voltage circuit breaker's operating status; and analyzing changes in the high-voltage circuit breaker's closing status to form a feature database, providing fault early warning for the entire lifespan of the high-voltage circuit breaker. Patent CN118169553A discloses a method for testing and analyzing the closing contact resistance of a circuit breaker. The method includes: when a power system fault occurs while the circuit breaker is in the closed state, recording the fault voltage and fault current waveforms using a fault recorder; decomposing the DC components of the fault voltage and fault current using a mathematical model algorithm; calculating the circuit breaker's closing contact resistance using Ohm's law; comparing this closing contact resistance value with the standard-specified closing contact resistance value; obtaining the analysis result of the circuit breaker's closing contact resistance; and generating an analysis report. Compared with existing technologies, this application can ensure the continuity of power supply and automatically and intelligently analyze whether the circuit breaker's closing contact resistance meets the requirements. It significantly saves labor and power outage costs, improves pre-testing efficiency, and eliminates the safety risks of power outage pre-testing. This solves the problems of high cost and large error in existing technologies. Patent CN115754695A discloses a method, system, and medium for identifying the state of a closing resistor. The method involves acquiring fault waveform data; extracting waveform segments with sudden current changes from the fault waveform data to obtain several waveform segment data; selecting any waveform segment data and calculating the corresponding resistance curve within that waveform segment data; traversing several waveform segment data to obtain several resistance curves; and comparing these resistance curves with the rated closing resistor resistance curve to obtain the closing resistor state. The beneficial effect of this invention is that by real-time monitoring of the sudden current changes in fault waveform data and converting it into a resistance curve for comparison with the rated resistance curve, the state of the closing resistor is determined. This achieves long-term real-time monitoring of the closing resistor state and avoids accidents such as insulation discharge or breakdown of the closing resistor.

[0004] The three invention patents mentioned above use an indirect data acquisition method, which is not accurate enough. Existing methods for determining the state of the closing resistor cannot provide criteria for whether the next action can proceed, nor can they indicate the discharge location of the closing resistor itself. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for identifying the state of closing resistor based on fiber optic sensing, which aims to solve the problems of existing methods for judging the state of closing resistor, which cannot provide a judgment on the next action of the closing resistor or the location of internal defects in the closing resistor.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a closing resistor status identification system based on fiber optic sensing, comprising a light source module, a circulator, a sensing fiber optic connector, an optical amplifier, a 1-to-2 coupler, a second optical filter, a first optical filter, a 2-in-1 coupler, a photoelectric converter, an analog-to-digital converter circuit, a microprocessor, and a server. The circulator is connected to the light source module, the sensing fiber optic connector, and the optical amplifier, respectively. The 1-to-2 coupler is connected to the optical amplifier, the first optical filter, and the second optical filter, respectively. The 2-in-1 coupler is connected to the first optical filter, the second optical filter, and the photoelectric converter, respectively. The microprocessor is connected to the analog-to-digital converter circuit and the server, respectively. The analog-to-digital converter circuit is connected to the photoelectric converter.

[0007] The light source module is used to output a light source;

[0008] The circulator is used to make the light source output in a ring pattern;

[0009] The sensing fiber optic connector is used to connect the optical fibers of different devices;

[0010] The optical amplifier is used to amplify the light source input to the circulator and output the amplified light from the output port;

[0011] The one-to-two coupler is used to split the input light source into two light source outputs;

[0012] The second optical filter is used for edge filtering of the falling edge of light of a specific wavelength;

[0013] The first optical filter is used for edge filtering of the rising edge of light of a specific wavelength;

[0014] The two-in-one coupler is used to combine two optical signals that have been edge-filtered and have a fixed optical transmission delay due to the difference in fiber length, and output them as a single optical signal to the photoelectric converter, thereby realizing the superposition of the optical domain power of the two optical signals.

[0015] The photoelectric converter is used to convert light into electric current;

[0016] The analog-to-digital converter circuit is used to convert analog signals into digital signals;

[0017] The microprocessor is used to receive the output data of the analog-to-digital conversion circuit, control the working mode of the light source module, and send the calculation results to the server;

[0018] The server is used to process signals and control the equipment.

[0019] The light source module is a broadband light source with a wavelength range of 1400nm to 1650nm.

[0020] The wavelengths of edge filtering for the first optical filter and the second optical filter are 1546nm, 1558nm, 1565nm and 1578nm, respectively. The optical fiber connecting the second optical filter to the two-in-one coupler is 500m long, and the optical fiber connecting the first optical filter to the two-in-one coupler is 0.5m long.

[0021] Secondly, the present invention also provides a method for identifying the closing resistor state based on fiber optic sensing, applied to the closing resistor state identification system based on fiber optic sensing as described above, characterized by comprising the following steps:

[0022] Control the output light pulse mode of the light source module and set the sampling frequency of the analog-to-digital conversion circuit, K, M, N;

[0023] Starting from the time the light pulse is emitted, data from the analog-to-digital conversion circuit is continuously received, and several sample points are received and counted into an array;

[0024] Take a specific number of sample points, and calculate SUM, outA, outB, and SubAB based on the specific number of sample points;

[0025] Determine if M is greater than 20. If so, calculate the four MeanABs respectively and compare the maximum value of the four MeanABs with the threshold. If it is greater than the threshold, the circuit breaker is not allowed to perform the next closing action. If it is less than the threshold, the circuit breaker is allowed to perform the next closing action. If not, calculate SUM, outA, outB and SubAB respectively.

[0026] Determine if N is greater than 20000. If so, calculate the amplitude and frequency of the Fast Fourier Transform for SubAB, and take the average of the 20 adjacent frequencies respectively. Fill the missing frequency samples at the end with zeros. If not, calculate SUM, outA, outB and SubAB respectively.

[0027] The frequency sampling of the SubAB Fast Fourier Transform determines whether the discharge threshold has been exceeded. If the discharge threshold has been exceeded, the system is considered to be discharging; otherwise, it is considered not to be discharging.

[0028] The calculation formulas for SUM, outA, outB, SubAB, and MeanAB are as follows:

[0029] Take i = 1~10, and calculate respectively:

[0030]

[0031] outA1(K) = the maximum value in SUM(i);

[0032] Take i = 26~35 and calculate respectively:

[0033]

[0034] outA2(K) = the maximum value in SUM(i);

[0035] Let i = 51~60, and calculate respectively:

[0036]

[0037] outA3(K) = the maximum value in SUM(i);

[0038] Let i = 76~85, and calculate respectively:

[0039]

[0040] outA4(K) = the maximum value in SUM(i);

[0041] Take i = 126~135 and calculate respectively:

[0042]

[0043] outB1(K) = the maximum value in SUM(i);

[0044] Take i = 151~160, and calculate respectively:

[0045]

[0046] outB2(K) = the maximum value in SUM(i);

[0047] Take i = 176~185, and calculate respectively:

[0048]

[0049] outB3(K) = the maximum value in SUM(i);

[0050] Let i = 201~210, and calculate respectively:

[0051]

[0052] outB4(K) = the maximum value in SUM(i);

[0053] calculate

[0054] SubAB1(K)=outA1(K)-outB1(K);

[0055] SubAB2(K)=outA2(K)-outB2(K);

[0056] SubAB3(K)=outA3(K)-outB3(K);

[0057] SubAB4(K)=outA4(K)-outB4(K);

[0058] K=K+1; M=M+1;

[0059] M=1; N=N+1;

[0060] Calculate separately:

[0061]

[0062]

[0063]

[0064] .

[0065] The present invention relates to a closing resistor status identification system based on fiber optic sensing. The light source module is a broadband light source with a wavelength range of 1400nm to 1650nm, connected to the input end of a circulator via optical fiber. The circulator has three ports: an input, an output port, and an output port. The input port is connected to the light source module via optical fiber. The input and output ports are connected to the sensing fiber optic connector. The output port is connected to the optical amplifier, which amplifies the input light source and outputs the amplified light from the output port. The input is connected to the output of the circulator via optical fiber, and its output is connected to a 1-to-2 coupler via optical fiber. The 1-to-2 coupler has one input end and two output ends; the input end is connected to the optical amplifier via optical fiber. The output end is connected to the second optical filter and the first optical filter respectively via optical fiber. The two-to-one coupler has two input ends and one output end; the two input ends are connected to the second optical filter and the first optical filter respectively. The input ends of the second optical filter and the first optical filter are each connected to one output of the one-to-two coupler via optical fiber; the output ends are each connected to one input / output of the two-to-one coupler via optical fiber. The second optical filter performs edge filtering on the rising edge of specific wavelength light, respectively filtering the rising edge of four wavelengths with center waves of 1546nm, 1558nm, 1565nm, and 1578nm. The first optical filter performs edge filtering on the falling edge of specific wavelength light, respectively filtering the falling edge of four wavelengths with center waves of 1546nm, 1558nm, 1565nm, and 1578nm. The four wavelengths of 1558nm, 1565nm, and 1578nm are filtered with a falling edge. The optical fiber connecting the first optical filter to the two-in-one coupler is relatively long, at 500 meters, while the optical fiber connecting the second optical filter to the two-in-one coupler is shorter, less than 0.5 meters. The input end of the photoelectric converter is connected to the output end of the two-in-one coupler via optical fiber; the output end is connected to the analog input end of the analog-to-digital converter circuit via a coaxial cable. The analog input end of the analog-to-digital converter circuit is connected to the output of the photoelectric converter. The digital output of the analog-to-digital converter circuit is connected to the microprocessor via a communication interface. The microprocessor connects to the analog-to-digital converter circuit via a communication interface to receive the output data from the circuit. It also connects to the light source via the same interface to control the light source's operating mode. Simultaneously, the microprocessor connects to the server via the same interface to send the calculation results to the server. This system can accurately collect parameters associated with the closing resistor, accurately determine the operating status of the closing resistor, and determine whether the closing resistor can perform the next operation. It can also determine the location of the closing resistor's discharge, thus solving the problem that existing methods for determining the status of the closing resistor cannot determine the next operation or the location of internal defects within the closing resistor. Attached Figure Description

[0066] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0067] Figure 1 This is a connection diagram of the closing resistor status identification method based on fiber optic sensing provided by the present invention.

[0068] Figure 2 This is a flowchart of the closing resistor status identification method based on fiber optic sensing provided by the present invention.

[0069] In the diagram: 101-Light source module, 102-Circulator, 103-Sensing fiber optic connector, 104-Optical amplifier, 105-One-to-two coupler, 106-Second optical filter, 107-First optical filter, 108-Two-in-one coupler, 109-Photoelectric converter, 110-Analog-to-digital converter circuit, 111-Microprocessor, 112-Server. Detailed Implementation

[0070] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0071] Please see Figure 1 In a first aspect, the present invention provides a closing resistor status identification system based on fiber optic sensing, comprising a light source module 101, a circulator 102, a sensing fiber optic connector 103, an optical amplifier 104, a 1-to-2 coupler 105, a second optical filter 106, a first optical filter 107, a 2-in-1 coupler 108, a photoelectric converter 109, an analog-to-digital converter circuit 110, a microprocessor 111, and a server 112. The circulator 102 is connected to the light source module 101, the sensing fiber optic connector 103, and the optical amplifier 104. The 1-to-2 coupler 105 is connected to the optical amplifier 104, the first optical filter 107, and the second optical filter 106. The 2-in-1 coupler 108 is connected to the first optical filter 107, the second optical filter 106, and the photoelectric converter 109. The microprocessor 111 is connected to the analog-to-digital converter circuit 110 and the server 112. The analog-to-digital converter circuit 110 is connected to the photoelectric converter 109.

[0072] The light source module 101 is used to output a light source;

[0073] The circulator 102 is used to make the light source output in a ring pattern;

[0074] The sensing fiber optic connector 103 is used to connect the optical fibers of different devices;

[0075] The optical amplifier 104 is used to amplify the light source input to the circulator 102 and output the amplified light from the output port;

[0076] The one-to-two coupler 105 is used to split the input light source into two light source outputs.

[0077] The second optical filter 106 is used for edge filtering of the falling edge of light of a specific wavelength;

[0078] The first optical filter 107 is used for edge filtering of the rising edge of light of a specific wavelength;

[0079] The two-in-one coupler 108 is used to combine two optical signals that have been edge-filtered and have a fixed optical transmission delay due to the difference in fiber length, and output them as a single optical signal to the photoelectric converter, thereby realizing the superposition of the optical domain power of the two optical signals.

[0080] The photoelectric converter 109 is used to convert light into electric current;

[0081] The analog-to-digital converter circuit 110 is used to convert analog signals into digital signals;

[0082] The microprocessor 111 is used to receive the output data of the analog-to-digital conversion circuit 110, control the working mode of the light source module 101, and send the calculation results to the server 112.

[0083] The server 112 is used to process signals and control the equipment.

[0084] In this embodiment of the invention, the light source module 101 is a broadband light source with a wavelength range of 1400nm to 1650nm. It is connected to the input end of the circulator 102 via optical fiber. The circulator 102 has three ports, including one input, one output port, and one output port. The input port is connected to the light source module 101 via optical fiber, the input and output ports are connected to the sensing fiber optic connector 103, and the output port is connected to the optical amplifier 104. The optical amplifier 104 amplifies the input light source and outputs the amplified light from the output port. The input is connected to the output of the circulator 102 via optical fiber, and its output is connected to the splitter coupler 105 via optical fiber. The splitter coupler 105 has one input end and two output ends. The input end is connected to the optical amplifier 104 via optical fiber, and the output end is connected to the optical amplifier 104 via optical fiber. The two-input coupler is connected to the second optical filter 106 and the first optical filter 107 respectively. The two inputs are connected to the second optical filter 106 and the first optical filter 107 respectively. The inputs of the second optical filter 106 and the first optical filter 107 are each connected to one output of the splitter coupler 105 via optical fibers. The outputs are each connected to one input / output of the coupler 108 via optical fibers. The second optical filter 106 performs edge filtering on the rising edge of specific wavelengths of light, providing edge filtering on the rising edge of four wavelengths with center waves of 1546nm, 1558nm, 1565nm, and 1578nm. The first optical filter 107 performs edge filtering on the falling edge of specific wavelengths of light, providing edge filtering on the falling edge of four wavelengths with center waves of 1546nm, 1558nm, 1565nm, and 1578nm respectively. The four wavelengths of 1558nm, 1565nm, and 1578nm are filtered at the falling edge. The optical fiber connecting the first optical filter 107 to the two-in-one coupler 108 is relatively long, at 500 meters. The optical fiber connecting the second optical filter 106 to the two-in-one coupler 108 is relatively short, with a length of less than 0.The photoelectric converter 109, with a length of 5 meters, has its input end connected to the output end of the two-in-one coupler 108 via an optical fiber. Its output end is connected to the analog input end of the analog-to-digital converter 110 via a coaxial cable. The analog input end of the analog-to-digital converter 110 is connected to the output of the photoelectric converter 109. The digital output of the analog-to-digital converter 110 is connected to the microprocessor 111 via a communication interface. The microprocessor 111 is also connected to the analog-to-digital converter 110 via a communication interface, receiving the output data from the circuit 110. It connects to the light source via the communication interface to control the light source's operating mode. Simultaneously, the microprocessor 111 connects to the server 112 via the communication interface to send the calculation results to the server 112. This system can accurately collect the associated parameters of the closing resistor, accurately determine the operating status of the closing resistor, and provide a judgment on whether the closing resistor can perform the next operation and the location of the discharge of the closing resistor. This solves the problem that existing methods for judging the status of the closing resistor cannot determine the next operation of the closing resistor or the location of internal defects in the closing resistor.

[0085] Please see Figure 2 Secondly, the present invention also provides a method for identifying the closing resistance state based on fiber optic sensing, applied to the closing resistance state identification system based on fiber optic sensing as described above, characterized by comprising the following steps:

[0086] S1 controls the output light pulse mode of the light source module 101 and sets the sampling frequency of the analog-to-digital conversion circuit 110, K, M, N;

[0087] In this embodiment of the invention, the optical pulse mode width is 200 ns, the frequency is 200 kHz, the sampling frequency is 50 MHz, K=1, M=1, N=1.

[0088] S2 continuously receives data from the analog-to-digital conversion circuit 110 from the start time of the light pulse emission, receives several sample points and counts them into an array;

[0089] In this embodiment of the invention, a total of 230 sample points are received and recorded in the array DATA

[230] .

[0090] S3 takes a specific number of sample points and calculates SUM, outA, outB and SubAB based on the specific number of sample points;

[0091] Take i = 1~10, and calculate respectively:

[0092]

[0093] outA1(K) = the maximum value in SUM(i) (i = 1~10);

[0094] Take i = 26~35 and calculate respectively:

[0095]

[0096] outA2(K) = the maximum value in SUM(i) (i = 26~35);

[0097] Let i = 51~60, and calculate respectively:

[0098]

[0099] outA3(K) = the maximum value in SUM(i) (i = 61~60);

[0100] Let i = 76~85, and calculate respectively:

[0101]

[0102] outA4(K) = the maximum value in SUM(i) (i = 76~85);

[0103] Take i = 126~135 and calculate respectively:

[0104]

[0105] outB1(K) = the maximum value in SUM(i) (i = 126~135);

[0106] Take i = 151~160, and calculate respectively:

[0107]

[0108] outB2(K) = the maximum value in SUM(i) (i = 151~160);

[0109] Take i = 176~185, and calculate respectively:

[0110]

[0111] outB3(K) = the maximum value in SUM(i) (i = 176~185);

[0112] Let i = 201~210, and calculate respectively:

[0113]

[0114] outB4(K) = the maximum value in SUM(i) (i = 201~210);

[0115] calculate

[0116] SubAB1(K)=outA1(K)-outB1(K);

[0117] SubAB2(K)=outA2(K)-outB2(K);

[0118] SubAB3(K)=outA3(K)-outB3(K);

[0119] SubAB4(K)=outA4(K)-outB4(K);

[0120] K=K+1; M=M+1;

[0121] S4 determines whether M is greater than 20. If so, it calculates the four MeanABs respectively and compares the maximum value of the four MeanABs with the threshold. If it is greater than the threshold, the circuit breaker is not allowed to perform the next closing action. If it is less than the threshold, the circuit breaker is allowed to perform the next closing action. If not, it calculates SUM, outA, outB and SubAB respectively.

[0122] In this embodiment of the invention, M=1; N=N+1;

[0123] Calculate separately:

[0124]

[0125]

[0126]

[0127]

[0128] Calculate the maximum values ​​of MeanAB1, MeanAB2, MeanAB3, and MeanAB4; if the maximum value is greater than the threshold Tmax, the circuit breaker is not allowed to perform the next closing action; if it is less than or equal to Tmax, the circuit breaker is allowed to perform the next closing action; Tmax is determined by testing.

[0129] S5 determines whether N is greater than 20000. If so, it calculates the amplitude and frequency of the fast Fourier transform of SubAB and takes the average of 20 adjacent frequencies. Missing frequency samples at the end are filled with zeros. If not, it calculates SUM, outA, outB and SubAB respectively.

[0130] In this embodiment of the invention, it is determined whether N is greater than 20000. If so, the amplitude of the fast Fourier transform is calculated for SubAB1, SubAB2, SubAB3, and SubAB4 respectively. For each fast Fourier transform frequency of SubAB1, SubAB2, SubAB3, and SubAB4, the average value of 20 adjacent frequencies is taken respectively, and the missing frequency samples at the end are filled with zeros.

[0131] S6 determines whether the discharge threshold is exceeded based on the frequency samples of the SubAB Fast Fourier Transform. If the discharge threshold is exceeded, it is considered to be discharged; otherwise, it is considered not to be discharged.

[0132] In this embodiment of the invention, for each frequency sample point of the fast Fourier transform of SubAB1, SubAB2, SubAB3, and SubAB4, it is determined whether the discharge judgment threshold is exceeded. If the discharge judgment threshold is exceeded, it is considered that a discharge has occurred; otherwise, it is considered that no discharge has occurred.

[0133] The discharge location is close to the sensor location corresponding to the highest amplitude among the same frequency values ​​of SubAB1, SubAB2, SubAB3, and SubAB4; the discharge judgment threshold for each frequency is determined experimentally; K=1; N=1.

[0134] The above-disclosed embodiments are merely preferred embodiments of the closing resistance state identification method and system based on fiber optic sensing of the present invention. Of course, they should not be construed as limiting the scope of the present invention. Those skilled in the art can understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A closing resistor status identification system based on fiber optic sensing, characterized in that: The system includes a light source module, a circulator, a sensing fiber optic connector, an optical amplifier, a 1-to-2 coupler, a second optical filter, a first optical filter, a 2-in-1 coupler, a photoelectric converter, an analog-to-digital converter circuit, a microprocessor, and a server. The circulator is connected to the light source module, the sensing fiber optic connector, and the optical amplifier. The 1-to-2 coupler is connected to the optical amplifier, the first optical filter, and the second optical filter. The 2-in-1 coupler is connected to the first optical filter, the second optical filter, and the photoelectric converter. The microprocessor is connected to the analog-to-digital converter circuit and the server. The analog-to-digital converter circuit is connected to the photoelectric converter. The light source module is used to output a light source; The circulator is used to make the light source output in a ring pattern; The sensing fiber optic connector is used to connect the optical fibers of different devices; The optical amplifier is used to amplify the light source input to the circulator and output the amplified light from the output port; The one-to-two coupler is used to split the input light source into two light source outputs; The second optical filter is used for edge filtering of the falling edge of light of a specific wavelength; The first optical filter is used for edge filtering of the rising edge of light of a specific wavelength; The two-in-one coupler is used to combine two optical signals that have been edge-filtered and have a fixed optical transmission delay due to the difference in fiber length, and output them as a single optical signal to the photoelectric converter, thereby realizing the superposition of the optical domain power of the two optical signals. The photoelectric converter is used to convert light into electric current; The analog-to-digital converter circuit is used to convert analog signals into digital signals; The microprocessor is used to receive the output data of the analog-to-digital conversion circuit, control the working mode of the light source module, and send the calculation results to the server; The server is used to process signals and control devices; The wavelengths for edge filtering of the first optical filter and the second optical filter are 1546nm, 1558nm, 1565nm and 1578nm, respectively. The optical fiber connecting the second optical filter to the two-in-one coupler is 500m long, and the optical fiber connecting the first optical filter to the two-in-one coupler is 0.5m long.

2. The closing resistor status identification system based on fiber optic sensing as described in claim 1, characterized in that... ； The light source module is a broadband light source with a wavelength range of 1400nm to 1650nm.

3. A method for identifying the closing resistance state based on fiber optic sensing, applied to the closing resistance state identification system based on fiber optic sensing as described in any one of claims 1-2, characterized in that, Includes the following steps: Control the output light pulse mode of the light source module and set the sampling frequency of the analog-to-digital conversion circuit, K, M, N; Starting from the time the light pulse is emitted, data from the analog-to-digital conversion circuit is continuously received, and several sample points are received and counted into an array; Take a specific number of sample points, and calculate SUM, outA, outB, and SubAB based on the specific number of sample points. The formulas for calculating SUM, outA, outB, SubAB, and MeanAB are as follows: Take i = 1~10, and calculate respectively: outA1(K) = the maximum value in SUM(i); Take i = 26~35 and calculate respectively: outA2(K) = the maximum value in SUM(i); Let i = 51~60, and calculate respectively: outA3(K) = the maximum value in SUM(i); Let i = 76~85, and calculate respectively: outA4(K) = the maximum value in SUM(i); Take i = 126~135 and calculate respectively: outB1(K) = the maximum value in SUM(i); Take i = 151~160, and calculate respectively: outB2(K) = the maximum value in SUM(i); Take i = 176~185, and calculate respectively: outB3(K) = the maximum value in SUM(i); Let i = 201~210, and calculate respectively: outB4(K) = the maximum value in SUM(i); calculate SubAB1(K)=outA1(K)-outB1(K); SubAB2(K)=outA2(K)-outB2(K); SubAB3(K)=outA3(K)-outB3(K); SubAB4(K)=outA4(K)-outB4(K); K=K+1; M=M+1; Determine if M is greater than 20. If so, calculate the four MeanABs respectively and compare the maximum value of the four MeanABs with the threshold. If it is greater than the threshold, the circuit breaker is not allowed to perform the next closing action. If it is less than the threshold, the circuit breaker is allowed to perform the next closing action. If not, calculate SUM, outA, outB and SubAB respectively. M=1; N=N+1; Calculate separately: ； Determine if N is greater than 20000. If so, calculate the amplitude and frequency of the Fast Fourier Transform for SubAB, and take the average of the 20 adjacent frequencies respectively. Fill the missing frequency samples at the end with zeros. If not, calculate SUM, outA, outB and SubAB respectively. The frequency sampling of the SubAB Fast Fourier Transform determines whether the discharge threshold has been exceeded. If the discharge threshold has been exceeded, the system is considered to be discharging; otherwise, it is considered not to be discharging.

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