Transformer partial discharge detection system and method
Through the combined system of optical fiber circulator, laser, direct-coupled acousto-optic sensor and interferometric laser processor, the problem of insufficient frequency coverage of transformer partial discharge detection in the existing technology is solved, and more accurate partial discharge detection is achieved.
Patent Information
- Application Number
- CN202510904320.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-01
- Publication Date
- 2025-10-17
AI Technical Summary
When detecting partial discharge in transformers, existing diaphragm, piezoelectric or indirect coupling fiber optic Fabry-Perot sensors have a narrow resonant frequency range and are unable to cover partial discharge signals of various frequencies, resulting in inaccurate detection.
A combined system of optical fiber circulator, laser, acousto-optic direct coupling sensor and interferometric laser processor is used to detect partial discharge of transformer by narrow-band laser. The interferometric laser processor is used to convert the interferometric laser into an electrical signal to judge partial discharge.
It achieves more accurate detection of transformer partial discharge, can effectively identify partial discharge in a wider frequency range, and improves the accuracy of detection.
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Figure CN120801941A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of transformer fault detection, in particular to a transformer partial discharge detection system and method. BACKGROUND
[0002] Insulation failure is the main cause of transformer failure, and large power transformers are mostly oil-immersed transformers using oil-paper insulation. Internal insulation defects such as bubbles, cracks, and electrode burrs will cause distortion of the electric field intensity in some areas, leading to partial breakdown of the insulation and generating partial discharge. The partial discharge occurring in the oil-paper insulation system of the transformer will generally excite ultrasonic signals. Optical fiber ultrasonic sensors have the advantages of being immune to electromagnetic interference, not easily damaged by strong electromagnetic processes, and can be built into electrical equipment, and are widely used in partial discharge detection of oil-paper insulation transformers.
[0003] For the currently more common diaphragm, piezoelectric or indirectly coupled fiber Fabry-Perot sensors, the detection principle is that the deformable mechanical structure in the sensor is displaced by the partial discharge ultrasonic wave, thereby changing the geometric length of the resonator. These three kinds of Fabry-Perot fiber sensors only show high sensitivity to the detection of ultrasonic signals within the set resonant frequency band, but their resonant frequency interval is relatively narrow, usually around 30 kHz, which is difficult to cover partial discharge signals of multiple different frequencies. SUMMARY
[0004] Therefore, it is necessary to provide a transformer partial discharge detection system and method that can more accurately detect transformer partial discharge in view of the above technical problems.
[0005] In a first aspect, the present application provides a transformer partial discharge detection system, which is installed on a transformer; the system comprises: a fiber optic circulator, a laser, an acousto-optic direct coupling sensor, and an interference laser processor.
[0006] The fiber optic circulator is used to connect the laser, the acousto-optic direct coupling sensor, and the interference laser processor; the laser is used to generate narrowband laser and output to the acousto-optic direct coupling sensor through the fiber optic circulator;
[0007] The sound-light direct coupling type sensor comprises: a fiber ferrule, a high reflection film sheet and a quartz sleeve; the quartz sleeve is a hollow structure with both ends closed; the high reflection film sheet is a disc with the same diameter as the quartz sleeve and is fixed at one end of the quartz sleeve; the fiber ferrule is inserted into the quartz sleeve through a preset hole at the other end of the quartz sleeve relative to the end where the high reflection film sheet is located, and the fiber ferrule and the high reflection film sheet are kept at a preset distance; the fiber ferrule is used to input the narrowband laser into the quartz sleeve, and the interference laser formed by the interference of the medium in the quartz sleeve is reflected to the fiber ferrule by the high reflection film sheet, and the fiber ferrule transmits the interference laser to the interference laser processor through the fiber circulator; when the transformer generates partial discharge, the density of the medium in the quartz sleeve is affected;
[0008] The interference laser processor is used to convert the interference laser into an electric signal, and judge whether the transformer has partial discharge according to the electric signal.
[0009] In one of the embodiments, the interference laser is a first interference laser or a second interference laser; the sound-light direct coupling type sensor is further used for:
[0010] When the transformer does not generate partial discharge, the medium in the quartz sleeve interferes with the narrowband laser to form a first interference laser; when the transformer generates partial discharge, the quartz sleeve generates ultrasonic signals through the partial discharge, which changes the phase of the narrowband laser to form a second interference laser.
[0011] In one of the embodiments, the high reflection film sheet comprises: a glass sheet and a medium reflection-increasing film; the glass sheet and the medium reflection-increasing film are both circular and have the same diameter as the quartz sleeve; the medium reflection-increasing film is plated on the glass sheet to form the high reflection film sheet, and the glass sheet of the high reflection film sheet is pasted on the inner wall of the quartz sleeve and is fixed at one end of the quartz sleeve.
[0012] In one of the embodiments, after the fiber ferrule is inserted into the quartz sleeve through the preset hole at the other end of the quartz sleeve relative to the end where the high reflection film sheet is located, the fiber ferrule is fixed on the quartz sleeve by an ultraviolet curing agent.
[0013] In one of the embodiments, the high reflection film sheet is fixed on the inner wall of one end of the quartz sleeve by an ultraviolet curing agent.
[0014] In one of the embodiments, the interference laser processor comprises: a photoelectric detector, a digital filter and a data acquisition system; the photoelectric detector is connected with the fiber circulator, the digital filter is connected with the photoelectric detector, and the data acquisition system is connected with the digital filter;
[0015] The photoelectric detector is configured to convert the interference laser into an electric signal and transmit the electric signal to the digital filter; the digital filter is configured to perform band-pass filtering and amplitude amplification on the electric signal to obtain a processed electric signal, and transmit the processed electric signal to the data acquisition system; and the data acquisition system is configured to determine whether the transformer generates partial discharge based on a waveform of the processed electric signal.
[0016] In one of the embodiments, the system is installed at a flange plate of the transformer.
[0017] In a second aspect, the application further provides a transformer partial discharge detection method, comprising:
[0018] The laser generates narrowband laser, which is output to a fiber ferrule of an acousto-optic direct coupling sensor through a fiber optic circulator;
[0019] The narrowband laser is input to a quartz sleeve of the acousto-optic direct coupling sensor through the fiber ferrule, and interference laser formed by interference of a medium in the quartz sleeve is reflected to the fiber ferrule by a high-reflective diaphragm of the acousto-optic direct coupling sensor, and the interference laser is transmitted to an interference laser processor through the fiber optic circulator; when the transformer generates partial discharge, the density of the medium in the quartz sleeve is affected;
[0020] The interference laser is converted into an electric signal by the interference laser processor, and whether the transformer has partial discharge is determined according to the electric signal.
[0021] In one of the embodiments, the interference laser is first interference laser or second interference laser; and the interference laser formed by interference of the medium in the quartz sleeve is reflected to the fiber ferrule by the high-reflective diaphragm of the acousto-optic direct coupling sensor, comprising:
[0022] When the transformer does not generate partial discharge, the first interference laser formed by interference of the medium in the quartz sleeve on the narrowband laser is reflected to the fiber ferrule by the high-reflective diaphragm of the acousto-optic direct coupling sensor; when the transformer generates partial discharge, the quartz sleeve generates ultrasonic signals by the partial discharge, which changes the phase of the narrowband laser to form second interference laser, and the second interference laser is reflected to the fiber ferrule by the high-reflective diaphragm of the acousto-optic direct coupling sensor.
[0023] In one of the embodiments, the interference laser is converted into an electric signal by the interference laser processor, and whether the transformer has partial discharge is determined according to the electric signal, comprising:
[0024] The photoelectric detector in the interference laser processor converts the interference laser into an electric signal and transmits the electric signal to a digital filter in the interference laser processor; the digital filter in the interference laser processor performs band-pass filtering and amplitude amplification on the electric signal to obtain a processed electric signal, and transmits the processed electric signal to a data acquisition system in the interference laser processor; the data acquisition system in the interference laser processor judges whether the transformer produces partial discharge based on the waveform of the processed electric signal.
[0025] The transformer partial discharge detection system and method, the system is installed on the transformer; the system comprises: a fiber optic circulator, a laser, an acousto-optic direct coupling sensor and an interference laser processor; the fiber optic circulator is used to connect the laser, the acousto-optic direct coupling sensor and the interference laser processor; the laser is used to generate narrowband laser and output to the acousto-optic direct coupling sensor through the fiber optic circulator; the acousto-optic direct coupling sensor comprises: a fiber ferrule, a high reflection film and a quartz sleeve; the quartz sleeve is a hollow structure with both ends closed; the high reflection film is a disc with the same diameter as the quartz sleeve and is fixed at the opening end of the quartz sleeve; the fiber ferrule is inserted into the quartz sleeve through a preset hole at the closed end of the quartz sleeve and maintains a preset distance from the high reflection film; the fiber ferrule is used to input the narrowband laser into the quartz sleeve, and the interference laser formed by the interference of the medium in the quartz sleeve is reflected to the fiber ferrule by the high reflection film, and the fiber ferrule transmits the interference laser to the interference laser processor through the fiber optic circulator; when the transformer produces partial discharge, it will affect the density of the medium in the quartz sleeve; the interference laser processor is used to convert the interference laser into an electric signal and judge whether the transformer has partial discharge according to the electric signal. The system in the present application can more accurately detect the partial discharge condition of the transformer. BRIEF DESCRIPTION OF DRAWINGS
[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technical solutions, the drawings needed to be used in the description of the embodiments of the present application or the related technical solutions will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other related drawings can be obtained by those skilled in the art without creative labor.
[0027] Figure 1 It is a structure diagram of the transformer partial discharge detection system in an embodiment;
[0028] Figure 2 It is a structure diagram of the acousto-optic direct coupling sensor in an embodiment;
[0029] Figure 3FIG. 4 is a flow chart of a transformer partial discharge detection method according to an embodiment. DETAILED DESCRIPTION
[0030] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.
[0031] It should be noted that the terms "first", "second", etc. used in this application may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from the second element. The terms "including" and "having" used in this application and any variations thereof are intended to cover non-exclusive inclusions. The term "plurality" used in this application refers to two or more. The term "and / or" used in this application refers to one of the solutions or any combination of multiple solutions.
[0032] In one embodiment, Figure 1 As shown, a transformer partial discharge detection system is provided, which is installed on the transformer; the system includes: an optical fiber circulator 101, a laser 102, an acousto-optic direct coupling sensor 103 and an interferometric laser processor 104;
[0033] The optical fiber circulator is used to connect a laser, an acousto-optic direct coupling sensor and an interferometric laser processor; the laser is used to generate narrow-band laser light and output it to the acousto-optic direct coupling sensor through the optical fiber circulator.
[0034] An optional single-film fiber circulator with a central wavelength of 1550 nm is used to connect the laser, acousto-optic direct coupling sensor, and an interferometric laser processor, forming a transmission loop for the laser beam. The laser has a central wavelength of 1550 nm, an operating linewidth of less than 200 kHz, and a rated output power of 20 dBm, generating narrowband laser light with tunable output wavelength.
[0035] The acousto-optic direct coupling type sensor comprises a fiber ferrule, a high reflection film and a quartz sleeve; the quartz sleeve is a hollow structure with both ends closed; the high reflection film is a disc with the same diameter as the quartz sleeve and is fixed at one end of the quartz sleeve; the fiber ferrule is inserted into the quartz sleeve through a preset hole at the other end of the quartz sleeve relative to the end where the high reflection film is located, and the fiber ferrule and the high reflection film are kept at a preset distance; the fiber ferrule is used to input the narrowband laser into the quartz sleeve, and the interference laser formed by the interference of the medium in the quartz sleeve is reflected to the fiber ferrule by the high reflection film, and the fiber ferrule transmits the interference laser to the interference laser processor through the fiber circulator; when the transformer generates partial discharge, the density of the medium in the quartz sleeve is affected.
[0036] Wherein, when the narrowband laser beam passes through the acousto-optic direct coupling type sensor, the laser generates interference in the Fabry-Perot cavity and is reflected back to the fiber, and the partial discharge ultrasonic signal changes the density of the medium in the Fabry-Perot cavity, thereby affecting the refractive index, so as to change the phase and light intensity of the reflected interference light.
[0037] Exemplary, Figure 2 The structure diagram of the acousto-optic direct coupling type sensor comprises a fiber ferrule 201, a high reflection film 202 and a quartz sleeve 203; the quartz sleeve is a hollow structure with both ends closed; the high reflection film is a disc with the same diameter as the quartz sleeve and is fixed at one end of the quartz sleeve; the fiber ferrule is inserted into the quartz sleeve through a preset hole at the other end of the quartz sleeve relative to the end where the high reflection film is located, and the fiber ferrule and the high reflection film are kept at a preset distance; the fiber ferrule is used to input the narrowband laser into the quartz sleeve, and the interference laser formed by the interference of the medium in the quartz sleeve is reflected to the fiber ferrule by the high reflection film, and the fiber ferrule transmits the interference laser to the interference laser processor through the fiber circulator; when the transformer generates partial discharge, the density of the medium in the quartz sleeve is affected.
[0038] The interference laser processor is used to convert the interference laser into an electric signal, and whether the transformer has partial discharge is judged according to the electric signal.
[0039] Wherein, after the partial discharge ultrasonic signal changes the density of the medium in the Fabry-Perot cavity, thereby affecting the refractive index, so as to change the phase and light intensity of the reflected interference light; the electric signals converted by different interference lasers are different, so as to judge whether the transformer has partial discharge.
[0040] The above-mentioned transformer partial discharge detection system is installed on the transformer; the system includes: an optical fiber circulator, a laser, an acousto-optic direct coupling sensor and an interferometric laser processor; the optical fiber circulator is used to connect the laser, the acousto-optic direct coupling sensor and the interferometric laser processor; the laser is used to generate narrowband laser light and output it to the acousto-optic direct coupling sensor through the optical fiber circulator; the acousto-optic direct coupling sensor includes: an optical fiber ferrule, a highly reflective diaphragm and a quartz sleeve; the quartz sleeve is a hollow structure with closed ends; the highly reflective diaphragm is a circular disc with the same diameter as the quartz sleeve and is fixed to the open end of the quartz sleeve. The optical fiber ferrule is inserted into the quartz sleeve through a preset hole at the closed end of the quartz sleeve, and maintains a preset distance from the high-reflection diaphragm. The optical fiber ferrule is used to input the narrowband laser into the quartz sleeve. The interference laser formed by the interference of the medium in the quartz sleeve is reflected by the high-reflection diaphragm to the optical fiber ferrule, and the optical fiber ferrule transmits the interference laser to the interference laser processor through the optical fiber circulator. When the transformer generates partial discharge, it will affect the density of the medium in the quartz sleeve. The interference laser processor is used to convert the interference laser into an electrical signal and determine whether the transformer has partial discharge based on the electrical signal. The system of the present application can more accurately detect the partial discharge of the transformer.
[0041] In an exemplary embodiment, the interference laser is a first interference laser or a second interference laser; and the acousto-optic direct coupling sensor is further used for:
[0042] When the transformer does not generate partial discharge, the medium in the quartz sleeve interferes with the narrowband laser to form a first interference laser. When the transformer generates partial discharge, the quartz sleeve changes the phase of the narrowband laser through the ultrasonic signal generated by the partial discharge to form a second interference laser.
[0043] Optionally, the medium may be insulating oil.
[0044] For example, when the transformer does not generate partial discharge, the medium in the quartz sleeve interferes with the narrowband laser to form a first interference laser. When the transformer generates partial discharge, the medium in the quartz sleeve changes its density due to the ultrasonic signal generated by the partial discharge. At this time, compared with the normal state, the phase of the narrowband laser is changed, forming a second interference laser.
[0045] Among them, the relationship between the change in insulating oil medium density Δρ and the ultrasonic signal sound pressure P is:
[0046]
[0047] in, is the static density of the insulating oil, is the volume of insulating oil. The refractive index n of the medium changes with the medium density ρ and satisfies the Lorenz-Lorentz relationship, as shown in the following formula:
[0048]
[0049] Among them, density fluctuation Δρ will cause refractive index fluctuation Δn, especially in the high-pressure area where the refractive index is higher and in the sparse area where it is lower. In summary, ultrasound directly modulates the density of insulating oil through mechanical pressure waves, thereby affecting the refractive index.
[0050] In this embodiment, the ultrasonic signal generated by partial discharge brings about a change in the medium density, thereby affecting the interference of the narrow-band laser, and can accurately distinguish whether the transformer has generated partial discharge.
[0051] In an exemplary embodiment, the high-reflection film includes: a glass sheet and a dielectric anti-reflection film; the glass sheet and the dielectric anti-reflection film are both circular and have the same diameter as the diameter of the quartz sleeve; the dielectric anti-reflection film is plated on the glass sheet to form a high-reflection film, and one side of the glass sheet of the high-reflection film is attached to the inner wall of the quartz sleeve and is fixed to one end of the quartz sleeve.
[0052] Among them, a glass sheet is used as the film substrate, and a dielectric anti-reflection film with a reflectivity of 99% is coated on the surface of the glass sheet to obtain a high-reflection film.
[0053] Exemplarily, the high-reflection film includes a glass sheet and a dielectric anti-reflection film; the glass sheet and the dielectric anti-reflection film are both circular, and their diameters are the same as the diameter of the quartz sleeve; the dielectric anti-reflection film is plated on the glass sheet to form a high-reflection film, and one side of the glass sheet of the high-reflection film is attached to the inner wall of the quartz sleeve and is fixed to one end of the quartz sleeve.
[0054] In this embodiment, by constructing a high-reflection diaphragm, the interference laser light after being changed by the medium can be effectively reflected back to the optical fiber ferrule for detection.
[0055] In an exemplary embodiment, the optical fiber ferrule is inserted into the quartz sleeve through a preset hole at the other end of the quartz sleeve relative to the end where the high-reflection diaphragm is located, and is then fixed to the quartz sleeve by an ultraviolet curing agent.
[0056] Exemplarily, the optical fiber ferrule is inserted into the quartz tube through a 0.3 mm hole at the other end of the quartz tube relative to the end where the high reflective film is located, and is fixed to the quartz tube by an ultraviolet curing agent.
[0057] In this embodiment, the optical fiber ferrule is fixed on the quartz sleeve, which can effectively input narrowband laser light and return interference laser light for subsequent detection.
[0058] In one exemplary embodiment, the high-reflective film is fixed on the inner wall of one end of the quartz sleeve by ultraviolet curing agent.
[0059] In one exemplary embodiment, the high-reflective film is fixed on the inner wall of one end of the quartz sleeve by ultraviolet curing agent.
[0060] In one exemplary embodiment, the high-reflective film is fixed on the inner wall of one end of the quartz sleeve by ultraviolet curing agent.
[0061] In one exemplary embodiment, the interference laser processor comprises a photodetector, a digital filter and a data acquisition system; the photodetector is connected with the fiber ring, the digital filter is connected with the photodetector, and the data acquisition system is connected with the digital filter.
[0062] The photodetector is configured to convert the interference laser into an electric signal and transmit the electric signal to the digital filter; the digital filter is configured to perform band-pass filtering and amplitude amplification on the electric signal to obtain a processed electric signal, and transmit the processed electric signal to the data acquisition system; and the data acquisition system is configured to determine whether the transformer generates partial discharge based on a waveform of the processed electric signal.
[0063] Optionally, the wavelength range of the photodetector is set to 1400nm-1650nm, the maximum conversion multiple is 20x106V / W, and the maximum response sensitivity is 2.0A / W. The photodetector is arranged at the end of the reflection light path and is configured to convert the reflected interference light signal into an electric signal. The band-pass spectrum of the digital filter is set to 10kHz-250kHz, and the signal gain multiple is 100. The digital filter is configured to perform band-pass filtering and amplitude amplification on the electric signal. The voltage range of the data acquisition system is ±5V, the rated sampling frequency is 100kHz, the trigger threshold of the partial discharge signal is set to five times the amplitude of the ambient noise, the oscilloscope displays the electric signal waveform converted by the photodetector after filtering and amplification, and transmits and stores the electric signal waveform to the computer system.
[0064] In one exemplary embodiment, the interference laser processor comprises a photodetector, a digital filter and a data acquisition system; the photodetector is connected with the fiber ring, the photodetector, the digital filter and the data acquisition system are connected in sequence.
[0065] The photodetector is configured to convert the interference laser into an electric signal and transmit the electric signal to the digital filter. The digital filter is configured to perform band-pass filtering and amplitude amplification on the electric signal to obtain a processed electric signal, and transmit the processed electric signal to the data acquisition system. The data acquisition system is configured to determine whether the transformer generates partial discharge based on a waveform of the processed electric signal.
[0066] In the embodiment, the interference laser is processed and detected by the photoelectric detector, the digital filter and the data acquisition system, so that whether the transformer has partial discharge can be accurately determined.
[0067] In an exemplary embodiment, the system is installed at the flange plate of the transformer.
[0068] Exemplarily, the transformer partial discharge detection system is installed at the flange plate of the transformer.
[0069] In the embodiment, the transformer partial discharge detection system is installed at the flange plate of the transformer, so that whether the transformer has partial discharge can be accurately detected.
[0070] In one embodiment, as shown in Figure 3 A transformer partial discharge detection method is provided, applied to the transformer partial discharge detection system, and the method comprises steps 302-306:
[0071] Step 302: Narrowband laser is generated by a laser and output to a fiber ferrule of an acousto-optic direct coupling sensor through a fiber circulator.
[0072] The laser and the acousto-optic direct coupling sensor are linked through the fiber circulator, and the fiber circulator also links an interference laser processor.
[0073] Step 304: The narrowband laser is input to a quartz sleeve of the acousto-optic direct coupling sensor through the fiber ferrule, and the interference laser formed by the interference of the medium in the quartz sleeve is reflected to the fiber ferrule by a high-reflection diaphragm of the acousto-optic direct coupling sensor, and the interference laser is transmitted to the interference laser processor through the fiber circulator through the fiber ferrule; when the transformer has partial discharge, the density of the medium in the quartz sleeve will be affected.
[0074] The acousto-optic direct coupling sensor comprises the fiber ferrule, the high-reflection diaphragm and the quartz sleeve; the quartz sleeve is a hollow structure with both ends closed; the high-reflection diaphragm is a disc with the same diameter as the quartz sleeve, fixed at one end of the quartz sleeve; the fiber ferrule is inserted into the quartz sleeve through a preset hole at the other end of the quartz sleeve relative to the end where the high-reflection diaphragm is located, and maintains a preset distance from the high-reflection diaphragm.
[0075] Step 306: The interference laser is converted into an electrical signal by the interference laser processor, and whether the transformer has partial discharge is determined according to the electrical signal.
[0076] The interference laser processor comprises a photoelectric detector, a digital filter and a data acquisition system.
[0077] The transformer partial discharge detection method comprises the following steps: a laser generates narrowband laser light, and the narrowband laser light is output to a fiber ferrule of an acousto-optic direct coupling sensor through a fiber circulator; the narrowband laser light is input to a quartz sleeve of the acousto-optic direct coupling sensor through the fiber ferrule, and interference laser light formed by interference of a medium in the quartz sleeve is reflected to the fiber ferrule by a high-reflection diaphragm of the acousto-optic direct coupling sensor; the interference laser light is transmitted to an interference laser processor through the fiber circulator through the fiber ferrule; when the transformer generates partial discharge, the density of the medium in the quartz sleeve is affected; the interference laser light is converted into an electric signal by the interference laser processor, and whether the transformer has partial discharge is determined according to the electric signal. The method can more accurately detect the partial discharge of the transformer.
[0078] In an exemplary embodiment, the interference laser light is first interference laser light or second interference laser light; the interference laser light formed by interference of the medium in the quartz sleeve is reflected to the fiber ferrule by the high-reflection diaphragm of the acousto-optic direct coupling sensor, comprising:
[0079] When the transformer does not generate partial discharge, the first interference laser light formed by interference of the medium in the quartz sleeve on the narrowband laser light is reflected to the fiber ferrule by the high-reflection diaphragm of the acousto-optic direct coupling sensor; when the transformer generates partial discharge, the quartz sleeve generates ultrasonic signals by the partial discharge, which changes the phase of the narrowband laser light to form second interference laser light, and the second interference laser light is reflected to the fiber ferrule by the high-reflection diaphragm of the acousto-optic direct coupling sensor.
[0080] For example, when the transformer does not generate partial discharge, the medium in the quartz sleeve interferes with the narrowband laser light to form first interference laser light, and the first interference laser light is reflected to the fiber ferrule by the high-reflection diaphragm of the acousto-optic direct coupling sensor; when the transformer generates partial discharge, the medium in the quartz sleeve changes the density by ultrasonic signals generated by the partial discharge, and the phase of the narrowband laser light is changed compared to the normal state to form second interference laser light; the second interference laser light is reflected to the fiber ferrule by the high-reflection diaphragm of the acousto-optic direct coupling sensor.
[0081] In this embodiment, the ultrasonic signals generated by the partial discharge change the density of the medium, which further affects the interference of the narrowband laser light, and the transformer can be accurately determined whether the transformer generates partial discharge.
[0082] In an exemplary embodiment, the interference laser light is converted into an electric signal by the interference laser processor, and whether the transformer has partial discharge is determined according to the electric signal, comprising:
[0083] The photodetector in the interference laser processor converts the interference laser into an electrical signal and transmits the electrical signal to a digital filter in the interference laser processor; the digital filter in the interference laser processor performs band-pass filtering and amplitude amplification on the electrical signal to obtain a processed electrical signal, and transmits the processed electrical signal to a data acquisition system in the interference laser processor; and the data acquisition system in the interference laser processor determines whether the transformer has generated partial discharge based on the waveform of the processed electrical signal.
[0084] Exemplarily, the interference laser processor comprises a photodetector, a digital filter and a data acquisition system; the photodetector converts the interference laser into an electrical signal and transmits the electrical signal to the digital filter; the digital filter performs band-pass filtering and amplitude amplification on the electrical signal to obtain a processed electrical signal, and transmits the processed electrical signal to the data acquisition system; and the data acquisition system determines whether the transformer has generated partial discharge based on the waveform of the processed electrical signal.
[0085] In this embodiment, the interference laser is processed and detected by the photodetector, the digital filter and the data acquisition system, so that whether the transformer has generated partial discharge can be accurately determined.
[0086] It should be understood that, although each step in the flowchart involved in each embodiment as described above is displayed in sequence according to the arrow, these steps are not necessarily executed in sequence according to the arrow. Unless otherwise specified herein, the execution of these steps is not strictly limited in sequence, and these steps can be executed in other sequences. Moreover, at least part of the steps in the flowchart involved in each embodiment as described above can include multiple steps or stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution sequence of these steps or stages is not necessarily sequential, but can be executed in rotation or alternation with at least part of other steps or steps or stages in other steps. It can be understood that each step in different embodiments can be freely combined as needed, and various non-contradictory schemes formed by the combination are within the scope of protection of the present application.
[0087] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer readable storage medium, and when executed, can include the processes of the above-mentioned embodiment methods. Any reference to memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. The non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. The volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration but not limitation, the RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The database involved in the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a block chain, etc., without being limited thereto. The processor involved in the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., without being limited thereto.
[0088] 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 exist contradictions, they should be considered as the scope of the present application.
[0089] The above-described embodiments are merely illustrative of several embodiments of the present application, which are described in more detail and in a specific manner, but should not be construed as limiting the scope of the patent of the present application. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.
Claims
1. A transformer partial discharge detection system, characterized in that: The system is installed on a transformer; the system includes: an optical fiber circulator, a laser, an acousto-optic direct coupling sensor and an interferometric laser processor; The optical fiber circulator is used to connect the laser, the acousto-optic direct coupling sensor and the interferometric laser processor; the laser is used to generate narrow-band laser light and output it to the acousto-optic direct coupling sensor through the optical fiber circulator; The acousto-optic direct coupling sensor comprises: an optical fiber ferrule, a high-reflection diaphragm, and a quartz sleeve; the quartz sleeve is a hollow structure with both ends closed; the high-reflection diaphragm is a circular disc with the same diameter as the quartz sleeve and is fixed to one end of the quartz sleeve; the optical fiber ferrule is inserted into the quartz sleeve through a preset hole at the other end of the quartz sleeve relative to the end where the high-reflection diaphragm is located, and maintains a preset distance from the high-reflection diaphragm; the optical fiber ferrule is used to input the narrowband laser into the quartz sleeve, and the interference laser formed by the interference of the medium in the quartz sleeve is reflected by the high-reflection diaphragm to the optical fiber ferrule, and the optical fiber ferrule transmits the interference laser to the interference laser processor through the optical fiber circulator; when the partial discharge generated by the transformer, it will affect the density of the medium in the quartz sleeve; The interference laser processor is used to convert the interference laser into an electrical signal and determine whether partial discharge occurs in the transformer based on the electrical signal.
2. The system according to claim 1, wherein: The interference laser is a first interference laser or a second interference laser; the acousto-optic direct coupling sensor is further used for: When the transformer does not generate partial discharge, the medium in the quartz sleeve interferes with the narrowband laser to form a first interference laser; When the transformer generates partial discharge, the quartz sleeve changes the phase of the narrow-band laser through the ultrasonic signal generated by the partial discharge, thereby forming a second interference laser.
3. The system according to claim 1, wherein: The high-reflection film comprises: a glass sheet and a dielectric anti-reflection film; the glass sheet and the dielectric anti-reflection film are both circular, and the diameter is the same as the diameter of the quartz sleeve; The dielectric anti-reflection film is plated on the glass sheet to form a high-reflection film. One side of the glass sheet of the high-reflection film is attached to the inner wall of the quartz sleeve and is fixed to one end of the quartz sleeve.
4. The system according to claim 1, wherein: The optical fiber ferrule is inserted into the quartz sleeve through a preset hole at the other end of the quartz sleeve relative to the end where the high-reflection diaphragm is located, and is then fixed on the quartz sleeve by an ultraviolet curing agent.
5. The system according to claim 1, wherein: The high-reflection film is fixed on the inner wall of one end of the quartz sleeve through an ultraviolet curing agent.
6. The system according to claim 1, wherein: The interference laser processor includes: a photoelectric detector, a digital filter and a data acquisition system; the photoelectric detector is connected to the optical fiber circulator, the digital filter is connected to the photoelectric detector; the data acquisition system is connected to the digital filter; The photodetector is used to convert the interference laser into an electrical signal and transmit the electrical signal to the digital filter; The digital filter is used to perform bandpass filtering and amplitude amplification on the electrical signal to obtain a processed electrical signal, and transmit the processed electrical signal to the data acquisition system; The data acquisition system is used to determine whether partial discharge occurs in the transformer based on the waveform of the processed electrical signal.
7. The system according to claim 1, wherein: The system is installed at the flange of the transformer.
8. A transformer partial discharge detection method, characterized in that: Applied to the system of claims 1-7, the method comprises: A narrowband laser is generated by a laser and outputted to a fiber optic ferrule of an acousto-optic direct coupling sensor through a fiber optic circulator; The narrowband laser is input into the quartz sleeve of the acousto-optic direct coupling sensor through the optical fiber ferrule. Interference laser light formed by interference of the medium in the quartz sleeve is reflected by the high-reflection diaphragm of the acousto-optic direct coupling sensor to the optical fiber ferrule. The interference laser light is then transmitted to the interference laser processor through the optical fiber ferrule via an optical fiber circulator. When partial discharge is generated by the transformer, the density of the medium in the quartz sleeve is affected. The interference laser is converted into an electrical signal by the interference laser processor, and whether there is partial discharge in the transformer is determined according to the electrical signal.
9. The method according to claim 8, characterized in that The interference laser is a first interference laser or a second interference laser; the interference laser formed by the interference of the medium in the quartz sleeve is reflected to the optical fiber ferrule by the high-reflection diaphragm of the acousto-optic direct coupling sensor, including: When the transformer does not generate partial discharge, the medium in the quartz sleeve interferes with the narrowband laser to form a first interference laser that is reflected by the high-reflection diaphragm of the acousto-optic direct coupling sensor to the optical fiber ferrule; When the transformer generates partial discharge, the quartz sleeve changes the phase of the narrowband laser through the ultrasonic signal generated by the partial discharge, forming a second interference laser. The second interference laser is reflected by the high-reflection diaphragm of the direct-acoustic-optical coupling sensor to the optical fiber ferrule.
10. The method according to claim 8, characterized in that The step of converting the interference laser into an electrical signal by the interference laser processor, and determining whether the transformer has partial discharge according to the electrical signal, includes: The photodetector in the interference laser processor converts the interference laser into an electrical signal, and transmits the electrical signal to the digital filter in the interference laser processor; The digital filter in the interference laser processor performs bandpass filtering and amplitude amplification on the electrical signal to obtain a processed electrical signal, and transmits the processed electrical signal to the data acquisition system in the interference laser processor; The data acquisition system in the interferometric laser processor determines whether partial discharge occurs in the transformer based on the waveform of the processed electrical signal.