Transformer winding vibration monitoring system and method

Abstract

The invention relates to a transformer winding vibration monitoring system and method. In the system, an optical signal distribution module divides laser into a first light beam and a second light beam; the interference module comprises a measuring optical fiber arranged on a transformer winding, the interference module divides the first light beam into a reference light beam and a measuring light beam, and the reference light beam and the measuring light beam passing through the measuring optical fiber are respectively reflected and interfered to obtain interference data; the scattering module comprises a sensing optical fiber arranged on a transformer winding, and is used for dividing the second light beam into first local oscillation light and second local oscillation light, sending the second local oscillation light to the sensing optical fiber to obtain Rayleigh scattering light, and modulating the first local oscillation light and the Rayleigh scattering light to obtain scattering data; and the signal processing module is used for analyzing the interference data to obtain frequency change information when the transformer winding vibrates, and demodulating the scattering data to obtain position information when the transformer winding vibrates. By adopting the method, the vibration monitoring accuracy and the calculation efficiency can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of transformers, in particular to a transformer winding vibration monitoring system and method. BACKGROUND

[0002] The transformer is an important power transmission and transformation equipment in the power grid, and its stable operation state is of great significance to the safety and reliability of the power grid. When the transformer fails, the vibration signal will change accordingly. Therefore, by monitoring the vibration, structural defects can be found in time, which is of great significance to ensure the normal operation of the transformer.

[0003] The current monitoring system generally uses a Mach-Zehnder interferometer for detection. However, the existing Mach-Zehnder interferometer needs to be connected with a one-to-two coupler and a photoelectric detector at the tail end of the optical fiber, and a separate signal loop is needed to return the signal. The arrangement process is complicated and the signal is easy to be disturbed in the transmission process. Therefore, there is an urgent need for a more efficient and more accurate transformer winding vibration monitoring system. SUMMARY

[0004] Therefore, it is necessary to provide a transformer winding vibration monitoring system and method that can improve the accuracy and efficiency of vibration monitoring.

[0005] In a first aspect, the present application also provides a transformer winding vibration monitoring system, comprising a laser emission module, an optical signal distribution module, an interference module, a scattering module and a signal processing module.

[0006] The laser emission module is configured to emit laser.

[0007] The optical signal distribution module is configured to divide the laser into a first light beam and a second light beam.

[0008] The interference module comprises a measurement optical fiber arranged on the transformer winding, and is configured to divide the first light beam into a reference light beam and a measurement light beam, reflect the reference light beam and the measurement light beam through the measurement optical fiber respectively, and interfere the two reflected light beams to obtain interference data.

[0009] The scattering module comprises a sensing optical fiber arranged on the transformer winding, and is configured to divide the second light beam into a first local oscillator light and a second local oscillator light, send the second local oscillator light to the sensing optical fiber to obtain Rayleigh scattered light, and modulate the first local oscillator light with the Rayleigh scattered light to obtain scattering data.

[0010] The signal processing module is configured to analyze the interference data to obtain frequency change information when the transformer winding vibrates, and demodulate the scattering data to obtain position information of the transformer winding vibration.

[0011] In one of the embodiments, the optical signal distribution module is a 1-to-2 fiber coupler.

[0012] In one of the embodiments, the interference module comprises a first transmission unit, a coupling unit and a first output unit; the first transmission unit is used to send the first light beam to the coupling unit; the coupling unit is used to divide the first light beam and also used to interfere to obtain interference light, and send the interference light to the first output unit through the first transmission unit; the first output unit is used to photoelectrically convert the interference light to obtain interference data.

[0013] In one of the embodiments, the first transmission unit is a fiber circulator; the coupling unit is a 1-to-2 fiber coupler; and the first output unit is a photodetector.

[0014] In one of the embodiments, the interference module further comprises a reference fiber, a first reflecting unit and a second reflecting unit; the reference light beam output end of the coupling unit is connected with the first reflecting unit through the reference fiber; and the measurement light beam output end of the coupling unit is connected with the second reflecting unit through the measurement fiber.

[0015] In one of the embodiments, the first reflecting unit and the second reflecting unit are Faraday mirrors respectively.

[0016] In one of the embodiments, the scattering module comprises a dividing unit, which is a fiber coupler with a set coupling ratio, and is used to divide the second light beam into first local oscillator light and second local oscillator light according to a set proportion corresponding to the set coupling ratio.

[0017] In one of the embodiments, the scattering module further comprises a first modulation unit, an amplification unit, a second transmission unit, a second modulation unit and a second output unit; the input end of the first modulation unit is connected with the second light beam output end of the dividing unit; the output end of the first modulation unit is connected with the sensing fiber through the amplification unit and the first channel of the second transmission unit; the second channel of the second transmission unit sends the Rayleigh scattering light to the second modulation unit; the second modulation unit also receives the first local oscillator light and modulates; the input end of the second output unit is connected with the second modulation unit; and the output end of the second output unit is connected with the signal processing module.

[0018] In one of the embodiments, the first modulation unit is an acousto-optic modulator, the amplification unit is an erbium-doped fiber amplifier, the second transmission unit is a fiber circulator, the second modulation unit is a coupler, and the second output unit is a balanced photodetector.

[0019] In a second aspect, the application provides a transformer winding vibration monitoring method, which is suitable for the system of the first aspect, and the method comprises the following steps:

[0020] In the case that the transformer winding to be detected vibrates, the laser emission module is controlled to start to generate laser;

[0021] The interference module and the scattering module are used to obtain interference data and scattering data respectively;

[0022] The signal processing module is used to analyze the interference data to obtain frequency change information when the transformer winding vibrates;

[0023] The signal processing module is used to demodulate the scattering data to obtain position information of the transformer winding that vibrates.

[0024] The transformer winding vibration monitoring system and method described above comprehensively use the laser emission module, the optical signal distribution module, the interference module, the scattering module and the signal processing module; the laser emission module is used to emit laser; the optical signal distribution module is used to divide the laser into the first light beam and the second light beam; the interference module comprises a measurement optical fiber arranged on the transformer winding, and is used to divide the first light beam into a reference light beam and a measurement light beam, reflect the reference light beam and the measurement light beam passing through the measurement optical fiber respectively, and interfere the two reflected lights to obtain interference data; in this case, the fiber interference of the interference module is used to obtain the interference data, so that the signal processing module obtains the frequency change information when the winding vibrates; the scattering module comprises a sensing optical fiber arranged on the transformer winding, and is used to divide the second light beam into a first local oscillator light and a second local oscillator light, send the second local oscillator light to the sensing optical fiber to obtain Rayleigh scattering light, and modulate the first local oscillator light with the Rayleigh scattering light to obtain scattering data; in this case, the scattering effect of the scattering module is used to obtain the scattering data, so that the signal processing module obtains the position information of the winding that vibrates; since the scattering effect positioning is more accurate, the accuracy of monitoring is improved; in addition, the interference module and the scattering module are used for parallel processing, which can greatly improve the calculation efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the application or the related art, the following will briefly introduce the drawings needed to be used in the description of the embodiments of the application or the related art. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0026] Figure 1 It is a block diagram of the transformer winding vibration monitoring system in an embodiment;

[0027] Figure 2 a block diagram of a transformer winding vibration monitoring system in another embodiment;

[0028] Figure 3 a flowchart of a transformer winding vibration monitoring method in another embodiment;

[0029] BRIEF DESCRIPTION OF DRAWINGS

[0030] 10 - laser emission module, 20 - optical signal distribution module, 30 - interference module, 40 - scattering module, 50 - signal processing module, 101 - 1550 nm laser, 201 - 1:2 optical fiber coupler, 301 - optical fiber circulator, 302 - 1:2 optical fiber coupler, 303 - reference arm optical fiber, 304 - measurement arm optical fiber, 305 - Faraday mirror, 306 - Faraday mirror, 307 - photodetector, 401 - balanced photodetector, 402 - coupler, 403 - 90:10 optical fiber coupler, 404 - acoustooptic modulator, 405 - erbium-doped fiber amplifier, 406 - optical fiber circulator, 407 - phase-sensitive optical time domain reflectometry sensing optical fiber, 501 - data acquisition card. DETAILED DESCRIPTION

[0031] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0032] It can be understood that the terms "first", "second" and the like used in the present application can be used in the present application to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element.

[0033] It can be understood that "connection" in the following embodiments means "electrical connection", "communication connection" and the like if the connected circuits, modules, units and the like have electrical signal or data transmission between each other.

[0034] As used herein, the singular forms "a", "an" and "the" can also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms "comprise / comprising" or "have / having" specify the presence of stated features, integers, steps, operations, components, parts or combinations thereof, but do not exclude the presence or addition of one or more other features, integers, steps, operations, components, parts or combinations thereof.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application.

[0036] To solve the problems in the prior art, the application provides a transformer winding vibration monitoring system and method, which is a transformer winding vibration monitoring system and method based on optical fiber interference and scattering effect, capable of obtaining spatial and temporal multidimensional distribution information of vibration information, and realizing measurement and real-time monitoring of the spatial and temporal distribution of the vibration field.

[0037] In an exemplary embodiment, as shown in Figure 1 A transformer winding vibration monitoring system is provided, which comprises a laser emission module 10, an optical signal distribution module 20, an interference module 30, a scattering module 40 and a signal processing module 50.

[0038] The laser emission module 10 is used for emitting laser. The output end of the laser emission module 10 is connected to the input end of the optical signal distribution module 20.

[0039] Exemplarily, a corresponding type of laser emission module is selected according to the requirement, and the laser emission module is used to emit laser to the optical signal distribution module.

[0040] The optical signal distribution module 20 is used for dividing the laser into a first light beam and a second light beam. The input end of the optical signal distribution module 20 is connected to the laser emission module 10, the first output end of the optical signal distribution module 20 is connected to the interference module 30, and the second output end of the optical signal distribution module 20 is connected to the scattering module 40.

[0041] Exemplarily, the optical signal distribution module receives laser from the laser emission module and divides the laser into a first light beam and a second light beam, which are respectively sent to the interference module and the scattering module.

[0042] The interference module 30 comprises a measurement optical fiber arranged on the transformer winding, the input end of the interference module 30 is connected to the first output end of the optical signal distribution module 20, and the output end of the interference module 30 is connected to the signal processing module 50.

[0043] The interference module 30 is used for dividing the first light beam into a reference light beam and a measurement light beam, reflecting the reference light beam and the measurement light beam passing through the measurement optical fiber respectively, and interfering the two reflected light beams to obtain interference data.

[0044] The interference module receives the first light beam from the optical signal distribution module, divides the first light beam into a reference light beam and a measurement light beam, reflects the reference light beam, reflects the measurement light beam passing through the measurement optical fiber, and interferes the two reflected light beams to obtain interference data.

[0045] The scattering module 40 includes a sensing optical fiber arranged on the transformer winding, the input end of the scattering module 40 is connected to the second output end of the optical signal distribution module 20, and the output end of the scattering module 40 is connected to the signal processing module 50.

[0046] The scattering module 40 is used for dividing the second light beam into a first local oscillator light and a second local oscillator light, sending the second local oscillator light to the sensing optical fiber to obtain Rayleigh scattering light, and modulating the first local oscillator light with the Rayleigh scattering light to obtain scattering data.

[0047] The scattering module receives the second light beam from the optical signal distribution module, divides the second light beam into a first local oscillator light and a second local oscillator light, sends the second local oscillator light to the sensing optical fiber to obtain Rayleigh scattering light output by the sensing optical fiber, and modulates the first local oscillator light with the Rayleigh scattering light to obtain scattering data.

[0048] The input end of the signal processing module 50 is connected to the interference module 30 and the scattering module 40 respectively. The signal processing module 50 is used for analyzing the interference data to obtain frequency change information when the transformer winding vibrates, and demodulating the scattering data to obtain position information of the transformer winding when the transformer winding vibrates.

[0049] In the above-mentioned transformer winding vibration monitoring system, the laser emission module, the optical signal distribution module, the interference module, the scattering module and the signal processing module are integrated; the laser emission module is used for emitting laser; the optical signal distribution module is used for dividing the laser into a first light beam and a second light beam; the interference module includes a measurement optical fiber arranged on the transformer winding, and is used for dividing the first light beam into a reference light beam and a measurement light beam, reflecting the reference light beam and the measurement light beam passing through the measurement optical fiber respectively, and interfering the two reflected light beams to obtain interference data; in this case, the interference data is obtained by the optical fiber of the interference module, so that the subsequent signal processing module obtains frequency change information when the winding vibrates; the scattering module includes a sensing optical fiber arranged on the transformer winding, and is used for dividing the second light beam into a first local oscillator light and a second local oscillator light, sending the second local oscillator light to the sensing optical fiber to obtain Rayleigh scattering light, and modulating the first local oscillator light with the Rayleigh scattering light to obtain scattering data; in this case, the scattering data is obtained by the scattering effect of the scattering module, so that the subsequent signal processing module obtains position information of the winding when the winding vibrates, and the positioning is more accurate due to the scattering effect, so that the monitoring accuracy is improved; in addition, the interference module and the scattering module are used for parallel processing, which can greatly improve the calculation efficiency.

[0050] In an exemplary embodiment, the optical signal distribution module 20 is a 1:2 fiber coupler.

[0051] The 1:2 fiber coupler is a core passive device, and the single input beam is evenly distributed to two output channels.

[0052] In this embodiment, the laser is divided into a first beam and a second beam by the 1:2 fiber coupler, which can achieve uniform distribution of optical signals while reducing costs.

[0053] In an exemplary embodiment, the interference module 30 includes a first transmission unit, a coupling unit, and a first output unit; the first transmission unit is used to send the first beam to the coupling unit; the coupling unit is used to divide the first beam and also used to interfere to obtain interference light, and the interference light is sent to the first output unit through the first transmission unit; the first output unit is used to photoelectrically convert the interference light to obtain interference data.

[0054] In this embodiment, the input optical path of the interference module (i.e., the optical path of the input first beam) and the output optical path (the optical path of the output interference light) are obtained through the first transmission unit, the coupling unit, and the first output unit, without a separate output optical path, which reduces the complexity of the monitoring system arrangement process.

[0055] In an exemplary embodiment, the first transmission unit is a fiber circulator; the coupling unit is a 1:2 fiber coupler; and the first output unit is a photodetector.

[0056] The fiber circulator is a multi-port optical device based on the non-reciprocity principle. The photodetector is a core device for converting optical signals into electrical signals.

[0057] In this embodiment, the fiber circulator is used to achieve unidirectional transmission of the first beam and the interference light, the 1:2 fiber coupler is used to divide the first beam, and the two reflected beams are coupled into one interference beam, which can reduce the number of components used and reduce the complexity of the monitoring system arrangement process. The photodetector is used to convert optical signals into electrical signals, which can improve the response speed and is beneficial to improving the calculation efficiency.

[0058] In an exemplary embodiment, the interference module 30 further includes a reference fiber, a first reflection unit, and a second reflection unit; the reference beam output end of the coupling unit is connected to the first reflection unit through the reference fiber; and the measurement beam output end of the coupling unit is connected to the second reflection unit through the measurement fiber.

[0059] The reference fiber is a fiber that is not arranged on the winding relative to the measurement fiber. The reflection unit is a device for reflecting a light beam.

[0060] In the embodiment, the frequency change information can be determined by the optical path difference through the reflected light passing through the reference optical fiber and the reflected light passing through the measurement optical fiber.

[0061] In one example embodiment, the first and second reflecting units are Faraday mirrors.

[0062] The Faraday mirror is a passive optical device based on the Faraday magneto-optical effect.

[0063] In the embodiment, the light beam is reflected by the Faraday mirror, which can realize high stability of the reflected light signal, avoid signal distortion, and be conducive to improving the accuracy of subsequent interference data.

[0064] In one example embodiment, the scattering module 40 includes a dividing unit, which is a fiber coupler with a set coupling ratio, for dividing the second light beam into the first and second local oscillation lights according to a set proportion corresponding to the set coupling ratio.

[0065] The fiber coupler with a set coupling ratio is a device that can divide the input light beam according to a set coupling ratio. The first local oscillation light is used as a reference signal for phase demodulation.

[0066] In the embodiment, the second light beam is divided by the fiber coupler with a set coupling ratio, which can better ensure that each branch obtains the light power as expected in design.

[0067] In one example embodiment, the scattering module further includes a first modulation unit, an amplification unit, a second transmission unit, a second modulation unit, and a second output unit. The input end of the first modulation unit is connected to the second light beam output end of the dividing unit. The output end of the first modulation unit is connected to the sensing optical fiber through the amplification unit and the first channel of the second transmission unit. The second channel of the second transmission unit sends Rayleigh scattered light to the second modulation unit. The second modulation unit also receives the first local oscillation light and modulates it. The input end of the second output unit is connected to the second modulation unit, and the output end of the second output unit is connected to the signal processing module.

[0068] In the embodiment, the second local oscillation light is processed by the first modulation unit and the amplification unit before being sent to the sensing optical fiber, which can enhance the intensity of the Rayleigh scattered light and overcome the attenuation problem of long-distance transmission, thereby improving the accuracy of the subsequent obtained scattering data. The processed second local oscillation light is sent to the sensing optical fiber by the second transmission unit, and the Rayleigh scattered light is sent to the second modulation unit, without the need for a separate channel to transmit the Rayleigh scattered light, reducing the complexity of the monitoring system arrangement process.

[0069] In one exemplary embodiment, the first modulation unit is an acousto-optic modulator, the amplification unit is an erbium-doped fiber amplifier, the second transmission unit is an optical fiber circulator, the second modulation unit is a coupler, and the second output unit is a balanced photodetector.

[0070] The acousto-optic modulator is a device that modulates continuous laser into a high-repetition-frequency pulse sequence based on the acousto-optic effect. The erbium-doped fiber amplifier is a key device for amplifying optical signals in an optical fiber communication system. The coupler is a device that distributes one input optical signal to multiple outputs or combines multiple signals into one output. The balanced photodetector is a high-precision detection device based on optical interference and electrical differential technology.

[0071] In this embodiment, the acousto-optic modulator can improve the response speed and improve the calculation efficiency of the system. The erbium-doped fiber amplifier can directly amplify the power of the modulated second local oscillator light, improve the gain of the second local oscillator light, and better improve the accuracy of the subsequent obtained scattering data. The balanced photodetector can better suppress light source noise and environmental interference, and improve the signal-to-noise ratio of the scattering data.

[0072] Exemplarily, as shown in Figure 2 The transformer winding vibration monitoring system specifically includes a 1550nm laser 101, a 1:2 optical fiber coupler 201, an optical fiber Michelson interference module, a phase-sensitive optical time domain reflectometer module, and a data acquisition card.

[0073] The optical fiber Michelson interference module includes an optical fiber circulator 301, a 1:2 optical fiber coupler 302, a reference arm optical fiber 303, a measurement arm optical fiber 304, a Faraday reflector 305, a Faraday reflector 306, and a photodetector 307.

[0074] The phase-sensitive optical time domain reflectometer module includes a balanced photodetector 401, a 2x2 coupler 402, a 90:10 optical fiber coupler 403, an acousto-optic modulator 404, an erbium-doped fiber amplifier 405, an optical fiber circulator 406, and a phase-sensitive optical time domain reflectometer sensing optical fiber 407.

[0075] In this embodiment, the 1550nm laser 101 is a 1550nm wavelength laser. The 1550nm laser 101 is used to emit laser light.

[0076] The 1:2 optical fiber coupler 201 is used to connect the 1550nm laser 101, the optical fiber circulator 301, and the 90:10 optical fiber coupler 403. The 1:2 optical fiber coupler 201 is also called a 50:50 optical fiber coupler.

[0077] The laser outputted by the 1550nm laser 101 is divided into two branches by a 1:2 fiber coupler 201, and the laser of the two branches (i.e. a first light beam and a second light beam) enters a fiber Michelson interference module and a phase-sensitive optical time domain reflectometer module respectively;

[0078] The laser entering the fiber Michelson interference module passes through a fiber circulator 301, and is inputted into a reference arm fiber 303 and a measurement arm fiber 304 by a 1:2 coupler 302 respectively, the output end of the reference arm fiber 303 is connected with a Faraday reflector 305, and the output end of the measurement arm fiber 304 is connected with a Faraday reflector 306. The return end of the fiber circulator 301 is connected with a photoelectric detector 307, the photoelectric detector 307 converts the corresponding optical signal into an electrical signal to obtain interference data and send the interference data into a data acquisition card 502 for data acquisition.

[0079] The fiber circulator 301 is used for connecting the 1:2 fiber coupler 201, the 1:2 fiber coupler 302 and the photoelectric detector 307, and the return light of the 1:2 fiber coupler 302 is injected into the photoelectric detector 307.

[0080] The 1:2 coupler 302 is used for connecting the fiber circulator 301, the reference arm fiber 303 and the measurement arm fiber 304.

[0081] The Faraday reflector 305 is used for reflecting the optical signal, so that the optical signal (i.e. a reference light beam) of the reference arm fiber 303 returns along the original light path.

[0082] The Faraday reflector 306 is used for reflecting the optical signal, so that the optical signal (i.e. a measurement light beam) of the measurement arm fiber 304 returns along the original light path.

[0083] The photoelectric detector 307 is used for receiving the return light (i.e. interference light obtained after two reflected lights interfere with each other) from the 1:2 fiber coupler 302 injected by the fiber circulator 301.

[0084] The laser entering the phase-sensitive optical time domain reflectometer module passes through a 90:10 coupler 403 and is divided into two branches, the branch laser with a proportion of 90 (i.e. a second local oscillator light) passes through an acousto-optic modulator 404 and an erbium-doped fiber amplifier 405, and a fiber circulator 406 enters a phase-sensitive optical time domain reflectometer sensing fiber 407. The return end of the fiber circulator 406 and the branch laser with a proportion of 10 (i.e. a first local oscillator light) enter a 2×2 fiber coupler 402 together, and then enter a balanced photoelectric detector 401. The balanced photoelectric detector 401 converts the corresponding optical signal into an electrical signal to obtain scattering data and send the scattering data into a data acquisition card 501 for data acquisition.

[0085] The acousto-optic modulator 404 is used for modulating the optical signal.

[0086] The erbium-doped fiber amplifier 405 is used to boost the optical power.

[0087] The fiber circulator 406 is used to connect the erbium-doped fiber amplifier 405, the phase-sensitive optical time domain reflectometer sensing fiber 407 and the 2×2 fiber coupler 402. The back Rayleigh scattering light returned by the phase-sensitive optical time domain reflectometer sensing fiber 407 is injected into the 2×2 fiber coupler 402.

[0088] The phase-sensitive optical time domain reflectometer sensing fiber 407 is used for vibration information sensing. The vibration information is propagated through the Rayleigh scattering light.

[0089] The balanced photodetector 401 is used to receive the optical signal from the 2×2 fiber coupler 402 and convert the received optical signal into an electrical signal. The interference optical signal is differentially amplified.

[0090] The 90:10 coupler 403 is used to connect the one-to-two fiber coupler 201, the 2×2 fiber coupler 402 and the acousto-optic modulator 404, and the laser is input into the acousto-optic modulator 404 and the 2×2 fiber coupler 402 in a ratio of 90:10.

[0091] The 2×2 fiber coupler 402 is used to modulate the phase of light.

[0092] The phase-sensitive optical time domain reflectometer sensing fiber 407 is adhered inside the transformer winding and fixed by an adhesive.

[0093] The data acquisition card 501 is used to collect and analyze the signals from the photodetector 307 and the balanced photodetector 401.

[0094] The analysis process of the data acquisition card 501 specifically includes:

[0095] The frequency change information of the transformer winding vibration is obtained by analyzing the interference data, specifically including: performing FFT (Fast Fourier Transform) processing on the data output by the photodetector 307 to obtain the frequency change information of the transformer winding vibration. Since different winding vibration information has different frequency characteristics, the frequency change information can be used to determine whether a fault has occurred.

[0096] The position information of the transformer winding vibration is obtained by demodulating the scattering data, specifically including:

[0097] The amplitude information is calculated by performing bandpass filtering, digital quadrature demodulation and low-pass filtering on the scattering data;

[0098] The quadrature demodulation (In-phase / Quadrature Demodulation) process is as follows: The orthogonal I and Q information obtained by calculation can be expressed as:

[0099]

[0100]

[0101] In the formula, represents the serial number of the sampling point, represents the total number of sampling points, represents the sampling signal (i.e. scattered data), represents the I homochromatic quadrature signal, represents the Q homochromatic quadrature signal, represents the sum frequency term in the I signal (i.e. the signal mapped to the I axis by the sampling signal), represents the sampling rate of the data acquisition card, represents the frequency of the modulation signal, represents the optical field intensity of the signal light (i.e. Rayleigh scattered light), represents the optical field intensity of the local oscillator light (i.e. the first local oscillator light), represents the phase of the external disturbance signal, represents the component containing the external disturbance signal in the I information, represents the sum frequency term in the Q signal, represents the component containing the external disturbance information in the Q signal, represents the I signal obtained by calculation, represents the Q signal obtained by calculation.

[0102] The sum frequency term in the I signal and the Q signal obtained by quadrature demodulation and is twice the frequency shifted by the AOM (acousto-optic modulator), and the double frequency can be filtered out by a low-pass filter to obtain and containing the external disturbance signal. and have the following relationship with and .

[0103]

[0104]

[0105] In the formula, represents the I signal after the low-pass filter, represents the Q signal after the low-pass filter, and in this embodiment, the I signal after the low-pass filter and the Q signal after the low-pass filter can be approximately equal to the result of the right side of the above relationship. Further, it can be obtained​​​​​ The amplitude information can be expressed as:

[0106] ;

[0107] According to the amplitude information , obtain the sampling point number at the vibration point where the amplitude protrudes, multiply the sampling point number by the sampling interval time and the speed of light, and then divide it by the refractive index of the optical fiber. The calculated value is divided by 2, which is the distance between the vibration point and the transmitting end.

[0108] The Michelson interference structure of the present invention responds more sensitively to the spectral characteristics of vibration information, and can compensate for the shortcomings of the phase-sensitive optical time-domain reflectometer structure in responding poorly to spectral characteristics. It has the advantages of a wide vibration frequency response range and high spatial resolution. Using only a phase-sensitive optical time-domain reflectometer to measure the frequency and position of vibration information, the data analysis process is complicated. However, by combining the Michelson interference structure with the phase-sensitive optical time-domain reflectometer, the Michelson structure analyzes the vibration frequency characteristics, and the phase-sensitive optical time-domain reflectometer analyzes the vibration position, which can effectively reduce the complexity of data analysis and improve the calculation speed. In addition, under long-distance monitoring conditions, the Michelson interference structure is simpler and easier to arrange. The phase-sensitive optical time-domain reflectometer accurately locates vibrations.

[0109] Based on the same inventive concept, the present application also provides a transformer winding vibration monitoring method using the aforementioned transformer winding vibration monitoring system. The implementation solution provided by this method is similar to the implementation solution described in the aforementioned system. Therefore, the specific limitations of one or more transformer winding vibration monitoring method embodiments provided below can be found in the above-mentioned limitations on the transformer winding vibration monitoring system, and will not be repeated here.

[0110] In an exemplary embodiment, Figure 3 As shown, a transformer winding vibration monitoring method is provided, comprising:

[0111] Step 602: When the transformer winding to be detected vibrates, control the laser emission module to start and generate laser light;

[0112] Step 604, using the interference module and the scattering module to obtain interference data and scattering data respectively;

[0113] Step 606: Analyze the interference data using a signal processing module to obtain frequency variation information when the transformer winding vibrates;

[0114] Step 608: Demodulate the scattered data using a signal processing module to obtain location information of the transformer winding where vibration occurs.

[0115] In the method of the present application, when the transformer winding to be detected vibrates, the light with vibration information corresponding is collected by the Michelson interference module and the phase sensitive optical time domain reflectometer module, and the corresponding interference data or scattering data are obtained, including the vibration information generated by the transformer no-load, normal load, core ungrounded and the like. The frequency change information of the vibration information is obtained by analyzing the interference data of the Michelson interference module; when the transformer winding to be detected vibrates, the optical path difference between the reference arm and the measurement arm in the Michelson interference module constantly changes due to the vibration of the transformer winding, resulting in the change of the waveform of the interference signal, so that the frequency change information is obtained. The position information of the vibration signal is obtained by analyzing the scattering data output by the balanced photodetector; when the transformer winding to be detected vibrates, the energy of the vibration position in the backscattering Rayleigh scattering light of the phase sensitive optical time domain reflectometer changes. The corresponding light signals are collected by the photodetector, the balanced photodetector and the data acquisition card. The light signals from the photodetector are subjected to frequency spectrum analysis, and the frequency characteristics of the vibration information are obtained. The scattering data from the balanced photodetector are demodulated, and the scattering data are subjected to band pass filtering, digital quadrature demodulation and low pass filtering, so that the position information of the vibration is obtained. The present application has the advantages that, compared with the prior art, the Michelson interference structure is more sensitive to the frequency spectrum characteristics of the vibration information, can compensate for the poor frequency spectrum characteristic response of the phase sensitive optical time domain reflectometer structure, has the advantages of wide vibration frequency response range and high spatial resolution. Only the phase sensitive optical time domain reflectometer is used to measure the frequency and position of the vibration information, and the data analysis process is complex, but by combining the Michelson interference structure with the phase sensitive optical time domain reflectometer, the Michelson structure analyzes the vibration frequency characteristics, and the phase sensitive optical time domain reflectometer analyzes the vibration position, which can effectively reduce the complexity of data analysis and improve the calculation speed.

[0116] The technical features of the above embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not contradict, they should be considered as falling within the scope of the present application.

[0117] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the patent of the present application. It should be pointed out that, for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all fall within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

[0118] It should be understood that, although the steps in the flowcharts involved in the embodiments described above are shown in sequence according to the arrows, the steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, the execution of the steps is not strictly limited in sequence, and the steps can be executed in other orders. Moreover, at least some of the steps in the flowcharts involved in the embodiments described above can include multiple steps or multiple stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution sequence of the steps or stages is not necessarily sequential, but can be executed alternately or alternately with at least part of other steps or steps or stages in other steps. The various modules in the transformer winding vibration monitoring system described above can be implemented wholly or partially by software, hardware, and combinations thereof.

Claims

1. A transformer winding vibration monitoring system, characterized in that: The system includes a laser emission module, an optical signal distribution module, an interference module, a scattering module and a signal processing module; The laser emission module is used to emit laser; The optical signal distribution module is used to split the laser into a first light beam and a second light beam; The interference module includes a measuring optical fiber arranged on the transformer winding, and is used to split the first light beam into a reference beam and a measuring beam, respectively reflect the reference beam and the measuring beam passing through the measuring optical fiber, and interfere the two reflected beams to obtain interference data; The scattering module includes a sensing optical fiber arranged on the transformer winding, and is used to split the second light beam into a first local oscillation light and a second local oscillation light, send the second local oscillation light to the sensing optical fiber to obtain Rayleigh scattered light, and modulate the first local oscillation light with the Rayleigh scattered light to obtain scattering data; The signal processing module is used to analyze the interference data to obtain frequency change information when the transformer winding vibrates, and demodulate the scattered data to obtain position information where the transformer winding vibrates.

2. The system according to claim 1, wherein: The optical signal distribution module is a one-to-two optical fiber coupler.

3. The system according to claim 1, wherein: The interference module includes a first transmission unit, a coupling unit and a first output unit; the first transmission unit is used to send the first light beam to the coupling unit; the coupling unit is used to split the first light beam and also to perform interference to obtain interference light, and then send the interference light to the first output unit via the first transmission unit, and the first output unit is used to perform photoelectric conversion on the interference light to obtain interference data.

4. The system according to claim 3, characterized in that The first transmission unit is a fiber circulator; the coupling unit is a one-to-two fiber coupler; and the first output unit is a photoelectric detector.

5. The system according to claim 3, wherein: The interference module also includes a reference optical fiber, a first reflection unit, and a second reflection unit. The reference beam output end of the coupling unit is connected to the first reflection unit via the reference optical fiber; the measurement beam output end of the coupling unit is connected to the second reflection unit via the measurement optical fiber.

6. The system according to claim 5, characterized in that The first reflecting unit and the second reflecting unit are respectively Faraday mirrors.

7. The system according to claim 1, wherein: The scattering module includes a dividing unit, which is a fiber coupler with a set coupling ratio, and is used to divide the second light beam into a first local oscillation light and a second local oscillation light according to a set ratio corresponding to the set coupling ratio.

8. The system according to claim 7, characterized in that The scattering module also includes a first modulation unit, an amplification unit, a second transmission unit, a second modulation unit, and a second output unit; the input end of the first modulation unit is connected to the second light beam output end of the dividing unit, the output end of the first modulation unit is connected to the sensing optical fiber via the amplification unit and the first channel of the second transmission unit, the second channel of the second transmission unit sends the Rayleigh scattered light to the second modulation unit, the second modulation unit also receives the first local oscillation light and modulates it, the input end of the second output unit is connected to the second modulation unit, and the output end of the second output unit is connected to the signal processing module.

9. The system according to claim 8, characterized in that The first modulation unit is an acousto-optic modulator, the amplification unit is an erbium-doped fiber amplifier, the second transmission unit is a fiber circulator, the second modulation unit is a coupler, and the second output unit is a balanced photodetector.

10. A transformer winding vibration monitoring method, characterized in that: Applicable to the system according to any one of claims 1 to 9, the method comprising: When the transformer winding to be detected vibrates, controlling the laser emission module to start to generate laser; Obtaining interference data and scattering data using an interference module and the scattering module respectively; Analyzing the interference data using a signal processing module to obtain frequency change information when the transformer winding vibrates; The signal processing module is used to demodulate the scattered data to obtain the position information of the transformer winding vibration.

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