Closing resistor state identification method and system based on optical fiber sensing

Abstract

The invention relates to the technical field of closing resistor state identification, in particular to a closing resistor state identification method and system based on optical fiber sensing. Comprising a light source module, a circulator, a sensing optical fiber connector, an optical amplifier, a one-to-two coupler, a second optical filter, a first optical filter, a two-in-one coupler, a photoelectric converter, an analog-to-digital conversion circuit, a microprocessor and a server, the first optical filter carries out edge filtering on a rising edge of light with a specific wavelength, the two-in-one coupler carries out edge filtering on a falling edge of the light with the specific wavelength, and the microprocessor receives output data of the analog-to-digital conversion circuit, controls a working mode of the light source module and sends an operation result to a server. The operation state of the closing resistor is accurately judged, whether the closing resistor can perform the next action or not can be judged, and the discharging position of the closing resistor can be given.

Description

Technical Field

[0001] The present invention relates to the technical field of closing resistance state identification, and in particular to a closing resistance state identification method and system based on optical fiber sensing. Background Art

[0002] The closing resistor is a very important component of the circuit breaker, and the status of the closing resistor needs to be evaluated to ensure the safe operation of the closing resistor.

[0003] At present, patent CN118169553A discloses a device and method for diagnosing the state of closing resistance of high-voltage circuit breaker, including a pressure difference acquisition module: used to obtain the pressure difference at both ends of the main circuit of the high-voltage circuit breaker when the closing resistance is put into operation; a current acquisition module: used to obtain the closing current of the main circuit of the high-voltage circuit breaker; a high-voltage circuit breaker intelligent diagnosis module: used to obtain the closing resistance input time, duration and dynamic waveform of the resistance within the duration period according to the pressure difference value and the current value, and then diagnose the closing resistance state according to it. The present invention uses a distributed monitoring device to synchronously collect the current waveform of the main circuit of the high-voltage circuit breaker and the voltage waveform at both ends of the main circuit to provide data support for fault diagnosis under the operating conditions of the circuit breaker; automatically calculate the closing resistance of the circuit breaker, the closing resistance input time and duration, and realize the intelligent detection of the operating state of the high-voltage circuit breaker; analyze the changes in the closing state of the high-voltage circuit breaker to form a feature database, and provide fault warning for the full life operation of the high-voltage circuit breaker. Patent CN118169553A discloses a test and analysis method for the closing contact resistance of a circuit breaker, including: when a power system fault occurs in the circuit breaker in the closed state, the fault voltage and fault current waveforms are recorded by a fault recorder, the DC component of the fault voltage and fault current is decomposed by a mathematical model algorithm, the closing contact resistance of the circuit breaker is calculated by Ohm's law, and the closing contact resistance value is compared with the closing contact resistance value specified in the standard to obtain the analysis result of the closing contact resistance of the circuit breaker, and generate an analysis report. Compared with the prior art, the present application can not only ensure the continuity of power supply, but also automatically and intelligently analyze whether the closing contact resistance of the circuit breaker meets the requirements. It greatly saves labor and power outage costs, improves pre-test efficiency, and eliminates the safety risks of power outage pre-test. Thereby solving the problem of high cost and large error of the prior art. Patent CN115754695A discloses a method, system and medium for identifying the state of a closing resistor, which obtains fault recording data; extracts the waveform segment of the current mutation in the fault recording data to obtain a plurality of waveform segment data; selects any waveform segment data, and calculates the corresponding resistance curve in the waveform segment data, traverses a plurality of waveform segment data, and obtains a plurality of resistance curves; compares the plurality of resistance curves with the rated closing resistor resistance curve, respectively, to obtain the state of the closing resistor; the beneficial effect of the present invention is that the state of the closing resistor is judged by real-time monitoring of the current mutation data of the fault recording data, and converting it into a resistance curve for comparison with the rated resistance curve, thereby realizing real-time monitoring of the state of the closing resistor and avoiding accidents of insulation discharge or breakdown of the closing resistor.

[0004] The above three invention patents adopt indirect data collection methods, which are not accurate enough. The existing closing resistor state judgment cannot give a criterion for whether the next action can be performed, nor can it give the position where the closing resistor itself is discharged. Summary of the invention

[0005] The purpose of the present invention is to provide a closing resistor state identification method and system based on optical fiber sensing, aiming to solve the problem that the existing closing resistor state judgment method cannot give a judgment on the next action of the closing resistor and cannot give the location of the internal defects of the closing resistor.

[0006] To achieve the above-mentioned object, in a first aspect, the present invention provides a closing resistance state identification system based on optical fiber sensing, comprising a light source module, a circulator, a sensing optical fiber connector, an optical amplifier, a one-to-two coupler, a second optical filter, a first optical filter, a two-in-one coupler, a photoelectric converter, an analog-to-digital conversion circuit, a microprocessor and a server, wherein the circulator is respectively connected to the light source module, the sensing optical fiber connector and the optical amplifier, the one-to-two coupler is respectively connected to the optical amplifier, the first optical filter and the second optical filter, the two-in-one coupler is respectively connected to the first optical filter, the second optical filter and the analog-to-digital conversion circuit, the microprocessor is respectively connected to the analog-to-digital conversion circuit and the server, and the analog-to-digital conversion circuit is connected to the light source module;

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

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

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

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

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

[0012] The second optical filter is used to filter the light source;

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

[0014] The two-in-one coupler is used for edge filtering of the falling edge of light of a specific wavelength;

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

[0016] The analog-to-digital conversion circuit is used to convert a digital signal into an analog signal;

[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 result to the server;

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

[0019] Wherein, the light source module is a broadband light source, and the wavelength range is 1400nm to 1650nm.

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

[0021] In a second aspect, the present invention further provides a closing resistance state identification method based on optical fiber sensing, which is applied to the closing resistance state identification system based on optical fiber sensing as described above, and is characterized in that it comprises the following steps:

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

[0023] From the start time of the light pulse, continuously receive the analog-to-digital conversion circuit data, receive a number of sample points and count them into an array;

[0024] Taking a specific number of samples, and calculating SUM, outA, outB and SubAB based on the specific number of samples;

[0025] Determine whether 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 whether N is greater than 20000. If so, calculate the amplitude and frequency of the fast Fourier transform of SubAB, and take the average of 20 adjacent frequencies respectively, and fill the missing frequency samples at the end with zero. If not, calculate SUM, outA, outB and SubAB respectively;

[0027] Based on the SubAB fast Fourier transform frequency sample points, it is determined whether the discharge judgment threshold is exceeded. If the discharge judgment threshold is exceeded, it is considered to be discharged; otherwise, it is considered not to be discharged.

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

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

[0030]

[0031] outA1(K) = the maximum value in SUM(i) (i = 1 to 10); take i = 26 to 35, and calculate respectively:

[0032]

[0033] outA2(K) = the maximum value in SUM(i) (i = 25 to 35); take i = 51 to 60, and calculate respectively:

[0034]

[0035] outA3(K) = the maximum value in SUM(i) (i = 61 to 60); take i = 76 to 85, and calculate respectively:

[0036]

[0037] outA4(K) = the maximum value in SUM(i) (i = 76 to 85); Step 8: Take i = 126 to 135 and calculate respectively:

[0038]

[0039] outB1(K) = the maximum value in SUM(i) (i = 126 to 135); take i = 151 to 160 and calculate respectively:

[0040]

[0041] outB2(K) = the maximum value in SUM(i) (i = 151 to 160); take i = 176 to 185, and calculate respectively:

[0042]

[0043] outB3(K) = the maximum value in SUM(i) (i = 176 to 185); take i = 201 to 210, and calculate respectively:

[0044]

[0045] outB4(K) = the maximum value in SUM(i) (i = 201 to 210); calculate

[0046] SubAB1(K)=outA1(K)-outB1(K);

[0047] SubAB2(K)=outA2(K)-outB2(K);

[0048] SubAB3(K)=outA3(K)-outB3(K);

[0049] SubAB4(K)=outA4(K)-outB4(K);

[0050] K = K + 1; M = M + 1;

[0051] M=1; N=N+1;

[0052] Calculate separately:

[0053]

[0054] Among them, SUM is the sum, SUBAB is the difference, meanAB is the sum of the differences, and outA and outB are the maximum values.

[0055] The optical fiber sensing-based closing resistance state identification system of the present invention, the light source module is a broadband light source with a wavelength range of 1400nm to 1650nm, connected to the input end of the circulator by an optical fiber, the circulator has three ports, including an input, an output port, and an output port, the input port is connected to the light source module by an optical fiber, the input and output ports are connected to the sensing optical fiber connector, the output port is connected to the optical amplifier, the optical amplifier is used to amplify the input light source and output the amplified light from the output port, the input is connected to the output of the circulator by an optical fiber, and the output is connected to the one-to-two coupler by an optical fiber, the one-to-two coupler has an input end , two output ends; the input end is connected to the optical amplifier by an optical fiber; the output end is respectively connected to the second optical filter and the first optical filter by an optical fiber, the two-in-one coupler has two input ends and one output end; the two input ends are respectively connected to the second optical filter and the first optical filter, the second optical filter and the first optical filter input ends are respectively connected to an output of the one-in-two coupler by an optical fiber; the output ends are respectively connected to an input and output of the two-in-one coupler by an optical fiber, the second optical filter, for edge filtering of the rising edge of light of a specific wavelength, respectively filters the four center waves of 1546nm, 1558nm, 1565nm and 1578nm The wavelength is filtered on the rising edge, the first optical filter filters the edge of the falling edge of the specific wavelength light, and respectively filters the four wavelengths with central waves of 1546nm, 1558nm, 1565nm and 1578nm on the falling edge. The optical fiber connected to the first optical filter and the two-in-one coupler is relatively long, which is 500 meters. The optical fiber connected to the second optical filter and the two-in-one coupler is relatively short, which is less than 0.5 meters in length. The input end of the photoelectric converter is connected to the output end of the two-in-one coupler with an optical fiber; the output end is connected to the analog input end of the analog-to-digital conversion circuit with a coaxial line, and the analog input end of the analog-to-digital conversion circuit is connected to the output of the photoelectric converter. The circuit digital output is connected to the microprocessor via a communication interface, the microprocessor is connected to the analog-to-digital conversion circuit via a communication interface, receives the output data of the analog-to-digital conversion circuit, and is connected to the light source via a communication interface to control the working mode of the light source. At the same time, the microprocessor is connected to the server via a communication interface to send the calculation result to the server. The system can accurately collect parameters related to the closing resistor, accurately judge the operating status of the closing resistor, and can give a judgment on whether the closing resistor can perform the next action and the discharge position of the closing resistor, which solves the problem that the existing closing resistor status judgment method cannot give a judgment on the next action of the closing resistor and cannot give the position of the internal defect of the closing resistor. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0057] Figure 1 It is a connection diagram of the closing resistance state identification method based on optical fiber sensing provided by the present invention.

[0058] Figure 2 The present invention provides a flow chart of a method for identifying a closing resistance state based on optical fiber sensing.

[0059] In the figure: 101-light source module, 102-circulator, 103-sensing fiber 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 conversion circuit, 111-microprocessor, 112-server. DETAILED DESCRIPTION

[0060] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0061] See also Figure 1 In a first aspect, the present invention provides a closing resistance state identification system based on optical fiber sensing, comprising a light source module 101, a circulator 102, a sensing optical fiber connector 103, an optical amplifier 104, a one-to-two coupler 105, a second optical filter 106, a first optical filter 107, a two-in-one coupler 108, a photoelectric converter 109, an analog-to-digital conversion circuit 110, a microprocessor 111 and a server 112, wherein the circulator 102 is respectively connected to the light source module 101, the sensing optical fiber connector 103 and the optical amplifier 104, the one-to-two coupler 105 is respectively connected to the optical amplifier 104, the first optical filter 107 and the second optical filter 106, the two-in-one coupler 108 is respectively connected to the first optical filter 107, the second optical filter 106 and the analog-to-digital conversion circuit 110, the microprocessor 111 is respectively connected to the analog-to-digital conversion circuit 110 and the server 112, and the analog-to-digital conversion circuit 110 is connected to the light source module 101;

[0062] The light source module 101 is used to output light source;

[0063] The circulator 102 is used to make the light source output in a ring shape;

[0064] The sensing optical fiber connector 103 is used to connect optical fibers of different devices;

[0065] 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;

[0066] The one-to-two coupler 105 is used to divide the input light source into two light source outputs;

[0067] The second optical filter 106 is used to filter the light source;

[0068] The first optical filter 107 is used for edge filtering of rising edges of light of a specific wavelength;

[0069] The two-in-one coupler 108 is used for edge filtering of the falling edge of light of a specific wavelength;

[0070] The photoelectric converter 109 is used to convert light into electric current;

[0071] The analog-to-digital conversion circuit 110 is used to convert a digital signal into an analog signal;

[0072] 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 result to the server 112;

[0073] The server 112 is used to process signals and control devices.

[0074] In an embodiment of the present invention, the light source module 101 is a broadband light source with a wavelength range of 1400nm to 1650nm, and is connected to the input end of the circulator 102 by an optical fiber. The circulator 102 has three ports, including an input, an output port, and an output port. The input port is connected to the light source module 101 by an optical fiber, the input and output ports are connected to the sensing fiber connector 103, and the output port is connected to the optical amplifier 104. The optical amplifier 104 is used to amplify the input light source and output the amplified light from the output port. The input is connected to the output of the circulator 102 by an optical fiber, and the output is connected to the one-to-two coupler 105 by an optical fiber. The one-to-two coupler 105 has an input end and two output ends; the input end is connected to the optical amplifier 104 by an optical fiber; the output end is respectively connected to the second optical filter 106 and the first optical filter 107 by optical fibers. The two-to-one coupler has two input ends and one output end; the two output ends are connected to the optical amplifier 104 by an optical fiber; the output end is respectively connected to the second optical filter 106 and the first optical filter 107 by optical fibers. The input end is connected to the second optical filter 106 and the first optical filter 107 respectively. The input ends of the second optical filter 106 and the first optical filter 107 are connected to one output of the one-to-two coupler 105 by optical fiber respectively; the output ends are connected to one input and output of the two-in-one coupler 108 by optical fiber respectively. The second optical filter 106 performs edge filtering on the rising edge of the specific wavelength light, and performs edge filtering on the rising edge of the four wavelengths with the center waves of 1546nm, 1558nm, 1565nm and 1578nm respectively. The first optical filter 107 performs edge filtering on the falling edge of the specific wavelength light, and performs edge filtering on the falling edge of the four wavelengths with the center waves of 1546nm, 1558nm, 1565nm and 1578nm respectively. The optical fiber connecting the first optical filter 107 and the two-in-one coupler 108 is relatively long, which is 500 meters. The optical fiber connecting the second optical filter 106 and the two-in-one coupler 108 is relatively short, which is less than 0.5 meters, the input end of the photoelectric converter 109 is connected to the output end of the two-in-one coupler 108 by optical fiber; the output end is connected to the analog input end of the analog-to-digital conversion circuit 110 by a coaxial line, the analog input end of the analog-to-digital conversion circuit 110 is connected to the output of the photoelectric converter 109, the digital output of the analog-to-digital conversion circuit 110 is connected to the microprocessor 111 by a communication interface, the microprocessor 111 is connected to the analog-to-digital conversion circuit 110 by a communication interface, receives the output data of the analog-to-digital conversion circuit 110, and is connected to the light source by a communication interface to control the working mode of the light source. At the same time, the microprocessor 111 is connected to the server 112 by a communication interface, and sends the calculation result to the server 112; the system can accurately collect the parameters related to the closing resistor, accurately judge the operating state of the closing resistor, and can give a judgment on whether the closing resistor can perform the next action, and can give the position of the closing resistor discharge, which solves the problem that the existing closing resistor state judgment method cannot give a judgment on the next action of the closing resistor and cannot give the position of the internal defect of the closing resistor. .

[0075] See also Figure 2 In a second aspect, the present invention further provides a closing resistance state identification method based on optical fiber sensing, which is applied to the closing resistance state identification system based on optical fiber sensing as described above, and is characterized in that it comprises the following steps:

[0076] S1 controls the light source module 101 to output a light pulse mode and sets the sampling frequency, K, M, N, of the analog-to-digital conversion circuit 110;

[0077] In the embodiment of the present invention, the optical pulse mode width is 200ns, the frequency is 200KHZ, the sampling frequency is 50MHZ, K=1, M=1, and N=1.

[0078] S2 continuously receives data from the analog-to-digital conversion circuit 110 from the start time of the light pulse, receives a number of sample points and counts them into an array;

[0079] In the embodiment of the present invention, a total of 230 samples are received and counted into the array DATA

[230] .

[0080] S3 takes a specific number of samples, and calculates SUM, outA, outB and SubAB based on the specific number of samples;

[0081] Take i = 1 to 10 and calculate respectively:

[0082]

[0083] outA1(K) = the maximum value in SUM(i) (i = 1 to 10);

[0084] Take i = 26 ~ 35, and calculate respectively:

[0085]

[0086] outA2(K) = the maximum value in SUM(i) (i = 25 to 35);

[0087] Take i = 51 ~ 60, and calculate respectively:

[0088]

[0089] outA3(K) = the maximum value in SUM(i) (i = 61 to 60);

[0090] Take i = 76 ~ 85, and calculate respectively:

[0091]

[0092] outA4(K) = the maximum value in SUM(i) (i = 76 to 85);

[0093] Take i = 126 ~ 135, and calculate respectively:

[0094]

[0095] outB1(K) = the maximum value in SUM(i) (i = 126 to 135);

[0096] Take i = 151 ~ 160, and calculate respectively:

[0097]

[0098] outB2(K) = the maximum value in SUM(i) (i = 151 to 160);

[0099] Take i = 176 ~ 185, and calculate respectively:

[0100]

[0101] outB3(K) = the maximum value in SUM(i) (i = 176 to 185); take i = 201 to 210, and calculate respectively:

[0102]

[0103] outB4(K) = the maximum value in SUM(i) (i = 201 to 210);

[0104] calculate

[0105] SubAB1(K)=outA1(K)-outB1(K);

[0106] SubAB2(K)=outA2(K)-outB2(K);

[0107] SubAB3(K)=outA3(K)-outB3(K);

[0108] SubAB4(K)=outA4(K)-outB4(K);

[0109] K = K + 1; M = M + 1;

[0110] S4 determines whether M is greater than 20. If so, four MeanABs are calculated respectively, and the maximum value among the four MeanABs is compared 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, SUM, outA, outB and SubAB are calculated respectively.

[0111] In the embodiment of the present invention, M=1; N=N+1;

[0112] Calculate separately:

[0113]

[0114] Among them, SUM is the sum, SUBAB is the difference, meanAB is the sum of the differences, and outA and outB are the maximum values.

[0115] Calculate the maximum value of MeanAB1, MeanAB2, MeanAB3, and MeanAB4; if the maximum value is greater than the threshold value 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 the test;

[0116] S5 determines whether N is greater than 20000. If so, the amplitude and frequency of the fast Fourier transform of SubAB are calculated, and the average values ​​of 20 adjacent frequencies are taken respectively, and the missing frequency samples at the end are filled with zeros. If not, SUM, outA, outB and SubAB are calculated respectively.

[0117] In the embodiment of the present 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 frequency sample points missing at the end are filled with zeros.

[0118] S6 determines whether the discharge judgment threshold is exceeded based on the SubAB fast Fourier transform frequency sample points. If the discharge judgment threshold is exceeded, it is considered to be discharged; otherwise, it is considered not to be discharged.

[0119] In the embodiment of the present invention, for each frequency sample point of the fast Fourier transform of SubAB1, SubAB2, SubAB3, and SubAB4, it is determined whether it exceeds the discharge determination threshold. If it exceeds the discharge determination threshold, it is considered that discharge occurs; otherwise, it is considered that no discharge occurs.

[0120] The discharge position is close to the corresponding sensor position with the highest amplitude among the same frequency amplitudes of SubAB1, SubAB2, SubAB3 and SubAB4; the discharge judgment threshold of each frequency is determined by experiments; K=1; N=1.

[0121] The above disclosure is only a preferred embodiment of the closing resistance state identification method and system based on optical fiber sensing of the present invention. Of course, this cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. The closing resistance state identification system based on optical fiber sensing is characterized by: It includes a light source module, a circulator, a sensing optical fiber connector, an optical amplifier, a one-to-two coupler, a second optical filter, a first optical filter, a two-in-one coupler, a photoelectric converter, an analog-to-digital conversion circuit, a microprocessor and a server, wherein the circulator is respectively connected to the light source module, the sensing optical fiber connector and the optical amplifier, the one-to-two coupler is respectively connected to the optical amplifier, the first optical filter and the second optical filter, the two-in-one coupler is respectively connected to the first optical filter, the second optical filter and the analog-to-digital conversion circuit, the microprocessor is respectively connected to the analog-to-digital conversion circuit and the server, and the analog-to-digital conversion circuit is connected to the light source module; The light source module is used to output light source; The circulator is used to make the light source output in a ring shape; The sensing optical fiber connector is used to connect optical fibers of different devices; The optical amplifier is used to amplify the circulator input light source and output the amplified light from the output port; The one-to-two coupler is used to divide the input light source into two light source outputs; The second optical filter is used to filter the light source; The first optical filter is used for edge filtering of rising edges of light of a specific wavelength; The two-in-one coupler is used for edge filtering of the falling edge of light of a specific wavelength; The photoelectric converter is used to convert light into electric current; The analog-to-digital conversion circuit is used to convert a digital signal into an analog signal; 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 result to the server; The server is used to process signals and control devices.

2. The closing resistance state identification system based on optical fiber sensing as claimed in claim 1, characterized in that ； The light source module is a broadband light source, and the wavelength range is 1400nm to 1650nm.

3. The closing resistance state identification system based on optical fiber sensing according to claim 1 is characterized in that ； The wavelengths of edge filtering of the first optical filter and the second optical filter are 1546nm, 1558nm, 1565nm and 1578nm, the length of the optical fiber connecting the second optical filter and the two-in-one coupler is 500m, and the length of the optical fiber connecting the first optical filter and the two-in-one coupler is 0.5m.

4. A closing resistor state identification method based on optical fiber sensing, applied to a closing resistor state identification system based on optical fiber sensing as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: Control the light source module to output the light pulse mode and set the analog-to-digital conversion circuit sampling frequency, K, M, N; From the start time of the light pulse, continuously receive the analog-to-digital conversion circuit data, receive a number of sample points and count them into an array; Taking a specific number of samples, and calculating SUM, outA, outB and SubAB based on the specific number of samples; Determine whether 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. Determine whether N is greater than 20000. If so, calculate the amplitude and frequency of the fast Fourier transform of SubAB, and take the average of 20 adjacent frequencies respectively, and fill the missing frequency samples at the end with zero. If not, calculate SUM, outA, outB and SubAB respectively; Based on the SubAB fast Fourier transform frequency sample points, it is determined whether the discharge judgment threshold is exceeded. If the discharge judgment threshold is exceeded, it is considered to be discharged; otherwise, it is considered not to be discharged.

5. The method for identifying the state of closing resistance based on optical fiber sensing according to claim 4, characterized in that ； The calculation formulas for SUM, outA, outB, SubAB and MeanAB are: Take i = 1 to 10 and calculate respectively: outA1(K) = the maximum value in SUM(i) (i = 1 to 10); Take i = 26 ~ 35, and calculate respectively: outA2(K) = the maximum value in SUM(i) (i = 25 to 35); Take i = 51 ~ 60, and calculate respectively: outA3(K) = the maximum value in SUM(i) (i = 61 to 60); Take i = 76 ~ 85, and calculate respectively: outA4(K) = the maximum value in SUM(i) (i = 76 to 85); Step 8: Take i = 126 to 135 and calculate respectively: outB1(K) = the maximum value in SUM(i) (i = 126 to 135); take i = 151 to 160 and calculate respectively: outB2(K) = the maximum value in SUM(i) (i = 151 to 160); take i = 176 to 185, and calculate respectively: outB3(K) = the maximum value in SUM(i) (i = 176 to 185); take i = 201 to 210, and calculate respectively: outB4(K) = the maximum value in SUM(i) (i = 201 to 210); 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; M=1; N=N+1; Calculate separately: Among them, SUM is the sum, SUBAB is the difference, meanAB is the sum of the differences, and outA and outB are the maximum values.

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