Partial discharge fault detection method and device based on optical micro-disk

Abstract

The invention relates to a partial discharge fault detection method and device based on an optical microdisk, and belongs to the technical field of fault detection. Comprises: emitting a laser signal; adjusting the intensity of the laser signal to obtain an adaptive laser signal; coupling an optical signal with a specific wavelength in the adaptive laser signal to form a stably existing standing wave, and obtaining a first optical signal; converting the first optical signal into an electric signal, and performing phase-sensitive demodulation on the electric signal to obtain position information of the sound signal; and identifying and positioning the partial discharge signal according to the position information. According to the invention, real-time online detection is realized, the detection efficiency is obviously improved, electromagnetic interference resistance is realized, the dependence on processing of a large amount of information is reduced, and the data processing time is shortened.

Description

Technical Field

[0001] The present invention relates to the technical field of fault detection, and in particular to a method and device for detecting partial discharge faults based on an optical microdisk. Background Art

[0002] As a key device in the power distribution system, the stable operation of distribution transformers is crucial to ensure the reliability of power supply and the safety of the power grid. Once a transformer fails, it will not only threaten the safety of the power grid, but may also cause huge economic losses. At present, many transformers have approached or reached their expected service life, but due to the lack of effective monitoring methods, the potential defects of these aging transformers are often not discovered in time, thereby increasing the risk of accidents.

[0003] In order to prevent such accidents, it is particularly necessary to conduct real-time monitoring and predictive maintenance of the transformer's operating conditions. Existing transformer detection technologies include pulse current method and ultra-high frequency detection method. Although the pulse current method is simple in principle, it is an offline detection method that is not suitable for real-time monitoring and is easily affected by electromagnetic interference. The ultra-high frequency detection method can achieve high-sensitivity online monitoring and defect location, but it has problems such as excessive amount of information, long data processing time and low detection efficiency in practical applications. In view of this, the existing methods have certain limitations in practical applications and cannot fully meet the needs of comprehensive and efficient monitoring of transformers. Summary of the invention

[0004] To this end, the technical problem to be solved by the present invention is to overcome the problems in the prior art such as the inability to conduct real-time online detection, susceptibility to electromagnetic interference, excessive amount of information, long data processing time and low detection efficiency.

[0005] In a first aspect, in order to solve the above technical problems, the present invention provides a partial discharge fault detection method based on an optical micro-disk, comprising:

[0006] emitting a laser signal;

[0007] Adjusting the intensity of the laser signal to obtain an adapted laser signal;

[0008] coupling an optical signal of a specific wavelength in the adapted laser signal to form a stable standing wave and obtain a first optical signal;

[0009] The first optical signal is converted into an electrical signal, and the electrical signal is phase-sensitively demodulated to obtain position information of the acoustic signal; and the partial discharge signal is identified and located according to the position information.

[0010] In one embodiment of the present invention, the method for coupling the optical signal of a specific wavelength in the adapted laser signal is a whispering gallery mode, and the whispering gallery mode includes coupling using a transmission matrix, and the expression of the transmission matrix is:

[0011]

[0012] Among them, b0, b1 and b2 are the output port optical energies of different mode lights, a0, a1 and a2 are the input port optical energies of different mode lights, t0, t1 and t2 are the transmission coefficients between different modes, j, k1, k2 and k c is the coupling coefficient between different modes.

[0013] In one embodiment of the present invention, during the coupling process of the optical signal of a specific wavelength in the adapted laser signal, there is a phase shift in the coupling between the straight waveguide and the ring waveguide, and different value ranges of the phase shift will change the resonance amplitude.

[0014] In one embodiment of the present invention, when the phase shift has a value range of (2m-0.5)π<θ<(2m+0.5)π, the mathematical expression of the resonance amplitude is:

[0015]

[0016] Where θ is the phase shift, m is a positive integer, π is the circumference of a circle, j and k c is the coupling coefficient between different modes, t1 and t2 are the transmission coefficients between different modes, b1 and b2 are the output port optical energies of different mode lights, α1 and α2 are the losses of the microdisk resonator, and Phase shift for different whispering gallery modes.

[0017] In one embodiment of the present invention, when the phase shift value range is (2m+0.5)π<θ<(2m+1)π, the mathematical expression of the resonance amplitude is:

[0018]

[0019] Where θ is the phase shift, m is a positive integer, π is the circumference of a circle, j and k c is the coupling coefficient between different modes, t1 and t2 are the transmission coefficients between different modes, b1 and b2 are the output port optical energies of different mode lights, α1 and α2 are the losses of the microdisk resonator, and Phase shift for different whispering gallery modes.

[0020] In one embodiment of the present invention, the calculation formula for the phase shift of the different whispering gallery modes is:

[0021]

[0022] in, is the phase shift of the i-th whispering gallery mode, i is a positive integer greater than zero, π is the circumference of a circle, R is the radius of the microdisk resonator, and n is eff_i is the effective refractive index corresponding to the i-th whispering gallery mode, and λ is the wavelength in vacuum.

[0023] In one embodiment of the present invention, the laser signal is a narrow linewidth laser signal.

[0024] In a second aspect, in order to solve the above technical problems, the present invention provides a partial discharge fault detection device based on an optical micro-disk, comprising:

[0025] A tunable laser for emitting a laser signal;

[0026] an attenuator, connected to the tunable laser by a multimode optical fiber, for adjusting the intensity of the laser signal to obtain an adapted laser signal;

[0027] at least one micro-disk resonator connected to the attenuator by an optical fiber, and used to couple the optical signal of a specific wavelength in the adapted laser signal to form a stable standing wave and obtain a first optical signal;

[0028] a photodetector connected to the at least one microdisk resonator using a single-mode optical fiber, and configured to convert the first optical signal into an electrical signal;

[0029] The signal acquisition module is directly connected to the photoelectric detector and is used to perform phase-sensitive demodulation on the electrical signal to obtain the position information of the acoustic signal.

[0030] In one embodiment of the present invention, each of the microdisk resonators comprises a straight waveguide and a polymer cladding.

[0031] In one embodiment of the present invention, a plurality of the microdisk resonators are distributed at equal intervals on the front and side surfaces of the transformer to form a microdisk resonator array.

[0032] The above technical solution of the present invention has the following beneficial effects compared with the prior art:

[0033] (1) The present invention discloses a method and device for detecting partial discharge faults based on an optical microdisk, which utilizes the instant response characteristics of laser signals to realize real-time online monitoring of partial discharge signals, so as to quickly identify and prevent potential equipment failures. In particular, the present invention performs well in environments that are sensitive to electromagnetic interference, showing excellent environmental adaptability. By precisely coupling optical signals of specific wavelengths to form stable standing waves, the method ensures the stability and reliability of signal processing. In addition, the present invention can quickly complete detection tasks, significantly reduce waiting time, avoid the need to process large amounts of information, and effectively improve work efficiency. Furthermore, by converting laser signals into electrical signals and performing demodulation operations, the present invention can accurately locate the position of acoustic signals, thereby achieving accurate identification and positioning of partial discharge signals.

[0034] (2) The microdisk resonator provided by the present invention uses a polymer material as a substrate instead of the original silicon substrate to form an all-polymer waveguide microdisk resonator, eliminating the problem of resonance wavelength drift. Compared with traditional piezoelectric ceramic hydrophones, the device of the present invention has the advantages of good electromagnetic compatibility, good insulation level, high acoustic sensitivity, wide frequency response, and high durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein

[0036] Figure 1 This is a flow chart of a partial discharge fault detection method based on an optical micro-disk in a preferred embodiment of the present invention;

[0037] Figure 2 A schematic diagram of the principle of a microdisk resonator in a preferred embodiment of the present invention;

[0038] Figure 3 This is a structural diagram of a partial discharge fault detection device based on an optical micro-disk in a preferred embodiment of the present invention;

[0039] Figure 4 A transmission curve diagram of a microdisk resonator in a preferred embodiment of the present invention;

[0040] Figure 5 FIG. 4 is a cross-sectional view of a microdisk resonator in a preferred embodiment of the present invention.

[0041] Explanation of the reference numerals in the specification: 1. tunable laser; 2. attenuator; 3. microdisk resonator; 4. photodetector; 5. signal acquisition module; 6. straight waveguide; 7. polymer cladding. DETAILED DESCRIPTION

[0042] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0043] Embodiment 1

[0044] Reference Figure 1 As shown, an embodiment of the present invention provides a partial discharge fault detection method based on an optical micro-disk, comprising:

[0045] emitting a laser signal;

[0046] Adjust the laser signal intensity to obtain an adapted laser signal;

[0047] Couple an optical signal of a specific wavelength in the adapted laser signal to form a stable standing wave, and obtain a first optical signal;

[0048] Converting the first optical signal into an electrical signal, and performing phase-sensitive demodulation on the electrical signal to obtain position information of the acoustic signal;

[0049] Based on the location information, the partial discharge signal is identified and located.

[0050] The embodiment of the present invention provides a partial discharge fault detection method based on an optical microdisk, which utilizes the rapid response capability of laser signals to achieve real-time online monitoring of partial discharge signals, effectively prevent and quickly identify potential equipment failures, and at the same time has electromagnetic interference resistance. By coupling optical signals of specific wavelengths to form stable standing waves, high stability and reliability of signal processing are ensured. The embodiment of the present invention can quickly perform detection tasks, significantly shorten waiting time, avoid the need to process large amounts of information, and effectively improve work efficiency. In addition, by converting laser signals into electrical signals and performing demodulation operations, the method can accurately capture the location information of acoustic signals, achieve accurate identification and positioning of partial discharge signals, and comprehensively and efficiently meet the needs of transformer monitoring.

[0051] Specifically, the method for coupling the optical signal of a specific wavelength in the adapted laser signal is the whispering gallery mode. The whispering gallery mode refers to the multiple reflections of light waves on the inner surface of an optical microresonator (such as a microsphere or microdisk) to form a special resonance mode. From the perspective of the microdisk resonator, this mode can be divided into two types: the external whispering gallery mode (mode 1) outside the disk and the internal whispering gallery mode (mode 2) inside the disk. In this embodiment, these two modes work together to form a 3×3 coupler. Figure 2 As shown in Figure 1, the coupling process of the whispering gallery mode involves the use of a transmission matrix to achieve effective coupling of light waves. The expression of the transmission matrix is:

[0052]

[0053] Among them, b0, b1 and b2 are the output port optical energies of different mode lights, a0, a1 and a2 are the input port optical energies of different mode lights, t0, t1 and t2 are the transmission coefficients between different modes, j, k1, k2 and k c is the coupling coefficient between different modes.

[0054] Furthermore, in the process of coupling the optical signal of a specific wavelength in the adapted laser signal, there is also a phase shift θ between the straight waveguide and the ring waveguide, which is calculated by:

[0055] θ=2π 2 R eff / λ; (2)

[0056] Where π is the circumference of a circle, R is the radius of the microdisk resonator, and n is eff is the effective refractive index corresponding to the whispering gallery mode, and λ is the wavelength in vacuum.

[0057] Furthermore, since the resonance amplitude of the microdisk resonator is affected by different phase shift values, this means that the range of phase shift changes the resonance response of the resonator directly. In this embodiment, when the phase shift θ ranges from (2m-0.5)π<θ<(2m+0.5)π, the mathematical expression of the resonance amplitude is:

[0058]

[0059] When the phase shift value range is (2m+0.5)π<θ<(2m+1)π, the mathematical expression of the resonance amplitude is:

[0060]

[0061] Where θ is the phase shift, m is a positive integer, j and k c is the coupling coefficient between different modes, t1 and t2 are the transmission coefficients between different modes, b1 and b2 are the output port optical energies of different mode lights, α1 and α2 are the losses of the microdisk resonator, and Phase shift for different whispering gallery modes.

[0062] Furthermore, for the phase shift of different whispering gallery modes, the calculation formula is:

[0063]

[0064] in, is the phase shift of the i-th whispering gallery mode, i is a positive integer greater than zero, and in this example, the value of i is 1 or 2; n eff_iis the effective refractive index corresponding to the i-th whispering gallery mode, and λ is the wavelength in vacuum.

[0065] In practical applications, high-Q microdisk resonators have a great influence on the transmission characteristics and phase shift near the resonance point. Very sensitive, this sensitivity is related to the refractive index n of the medium eff_i The weak changes caused by waveguide deformation are significantly amplified in the high-Q microdisk resonator, greatly improving the sensitivity to sound pressure. This means that even tiny environmental changes, such as pressure changes caused by sound waves, can be effectively detected by the microdisk resonator.

[0066] Furthermore, when the straight waveguide is coupled with the disk guide of the microdisk resonator, equations (3) and (4) can be simplified to:

[0067]

[0068] Among them, S t is the transmission function, a0 and b0 are the mode light energies of the straight waveguide input and output ports, and t0 is the transmission coefficient, which specifically represents the transmission loss from the straight waveguide to the microdisk.

[0069] In this embodiment, the whispering gallery mode is used to couple the optical signal of a specific wavelength in the adapted laser signal, which can effectively confine the optical signal of the specific wavelength inside the microdisk resonator, achieving efficient energy storage and resonance enhancement of the light wave. This coupling method not only improves the quality and intensity of the signal, but also greatly enhances the sensitivity to the optical signal due to the high Q factor of the whispering gallery mode.

[0070] Specifically, the electrical signal is phase-sensitively demodulated, and the phase-sensitive demodulation steps include rectification detection, phase-sensitive detection and matched filtering, and the filtered signal can reflect the acoustic signal information. In this embodiment, the phase-sensitive demodulation method is not limited and can be selected according to actual application needs.

[0071] Embodiment 2

[0072] Based on the same inventive concept, this embodiment provides a partial discharge fault detection device based on an optical micro-disk, and its principle of solving the problem is similar to that of a partial discharge fault detection method based on an optical micro-disk provided in the first embodiment, and the repeated parts are not repeated here.

[0073] Reference Figure 3 This embodiment provides a partial discharge fault detection device based on an optical micro-disk, comprising:

[0074] A tunable laser 1, used for emitting a laser signal;

[0075] Attenuator 2, connected to tunable laser 1 by multimode optical fiber, for adjusting the intensity of laser signal to obtain adapted laser signal;

[0076] At least one micro-disk resonator 3 is connected to the attenuator 2 by means of an optical fiber, and is used to couple an optical signal of a specific wavelength in the adapted laser signal to form a stable standing wave and obtain a first optical signal;

[0077] a photodetector 4 connected to at least one microdisk resonator 3 using a single-mode optical fiber, and configured to convert a first optical signal into an electrical signal;

[0078] The signal acquisition module 5 is directly connected to the photodetector 4 and is used to perform phase-sensitive demodulation on the electrical signal to obtain the position information of the acoustic signal.

[0079] This embodiment realizes real-time online detection of the local discharge signal of the device through a tunable laser 1, an attenuator 2, a microdisk resonator 3, a photodetector 4 and a signal acquisition module 5. Among them, the connection between the tunable laser 1 and the attenuator 2 can accurately control the intensity and wavelength of the emitted laser signal to adapt to different detection requirements. The signal acquisition module 5 is directly connected to the photodetector 4, which reduces the delay in the signal transmission process and speeds up the data processing speed. In addition, the connection of the optical fiber reduces electromagnetic interference and improves the stability and reliability of signal transmission.

[0080] Specifically, the present embodiment uses narrow linewidth laser signals, which play a vital role in many key fields such as optical interference, optical communication, precision measurement and quantum technology due to their excellent coherence, high spectral purity, system stability and long coherence length. In addition, narrow linewidth laser signals also have strong anti-electromagnetic interference capabilities and support remote control functions, which enables them to maintain high performance and precise operation even in complex and changing environments. Therefore, in the present embodiment, the tunable laser 1 is configured to emit a narrow linewidth laser signal, and its wavelength scanning range is set between 1.5 microns and 1.6 microns to optimize the coupling efficiency with the microdisk resonator 3. The transmission characteristics of the microdisk resonator 3 are as follows: Figure 4 shown.

[0081] Specifically, the attenuator 2 adjusts the intensity of the laser signal through the multimode optical fiber connected to the tunable laser 1 to obtain an adapted laser signal. This process involves precise program-controlled adjustment, and the attenuator 2 can change the loss of the optical signal in the transmission path to achieve flexible control of the light intensity. Multimode optical fiber is particularly suitable for the transmission of high-power optical signals because it can transmit optical signals in multiple modes. In this way, the attenuator 2 can adapt to the specific requirements of different application scenarios for the intensity of the laser signal, ensuring that the optical signal achieves optimal performance in subsequent optical sensing and signal processing applications. In this embodiment, the intensity of the laser signal transmitted by the attenuator 2 is adapted to the microdisk resonator 3.

[0082] During the operation of the distribution transformer, the acoustic signals generated by partial discharge have specific spectral characteristics, and their frequencies are mainly concentrated between 20kHz and 400kHz. In the medium of transformer oil, the wavelengths corresponding to these acoustic signals are approximately between 7.5 cm and 3.75 mm. There is a linear relationship between the sound pressure level of partial discharge and the discharge amount, which is crucial for monitoring and diagnosing the health of the transformer. In order to accurately capture these acoustic signals, the microdisk resonator 3 needs to have high sensitivity, a wide dynamic range, and an excellent signal-to-noise ratio. These performance parameters ensure that the microdisk resonator 3 can effectively detect the weak sound waves generated by partial discharge and convert them into analyzable electrical signals. In transformer oil, the working principle of the microdisk resonator 3 is mainly based on the physical effects caused by sound pressure. When sound waves propagate through transformer oil, they cause tiny deformations of the microdisk resonator 3, a phenomenon called acoustic pressure-induced deformation. At the same time, sound waves also cause photoelastic changes in the material, namely the photoelastic effect. In materials such as polystyrene, the photoelastic effect is particularly significant, which enables the microdisk resonator 3 to reflect the presence and intensity of sound waves through changes in optical signals.

[0083] Specifically, in the actual operating environment of the distribution transformer (large temperature difference operation), when the microdisk resonator 3 is placed inside the distribution transformer, the microdisk resonator 3 is easily affected by the operating temperature and the resonance wavelength drift occurs. The microdisk resonator 3 uses a polymer material as a substrate instead of the original silicon substrate to form a full polymer waveguide microdisk resonator 3, eliminating the resonance wavelength drift problem. Figure 5 The microdisk resonator 3 includes a straight waveguide 6 and a polymer cladding 7. The polymer cladding 7 is used to isolate the sensor from the transformer oil to avoid the influence of the transformer oil on the sensor structure and improve the system signal-to-noise ratio. The device described in this embodiment uses electron beam etching and nanoimprinting technology, which can reduce the production cost of the microdisk resonator 3.

[0084] Furthermore, the material of the microdisk resonator 3 may include polystyrene, a silicon dioxide insulating layer and a polymer cladding 7. Compared with the traditional piezoelectric ceramic hydrophone, it has the advantages of good electromagnetic compatibility, good insulation level, high acoustic sensitivity, wide frequency response, and high durability. The microdisk resonator 3 has practical significance for use in scenarios with large temperature changes. This makes the present invention widely applicable to the identification and positioning of partial discharge phenomena in transformers of various types, and can be used in actual production to prevent turn-to-turn short circuits and strand-to-strand short circuits caused by insulation degradation in advance, and avoid transformer explosion accidents caused by insulation defects.

[0085] Specifically, the microdisk resonator 3 has flexible installation options and can be built into the transformer or placed outside the transformer. These microdisk resonators 3 form an array (which can be called a microdisk resonator array), which are placed on insulating materials to ensure a safe distance from the transformer windings and tank walls to avoid electromagnetic interference. The microdisk resonator array is arranged in an equidistant manner on the front and sides of the transformer to form an effective sound wave receiving network. In this embodiment, 3-6 microdisk resonators 3 are arranged equidistantly on the front, and 3-6 microdisk resonators 3 are arranged equidistantly on the side to maximize the capture of direct stress wave signals generated by partial discharge events inside the transformer. Through this designed array, the sensitivity and coverage of signal reception can be significantly improved, thereby achieving real-time monitoring and accurate diagnosis of the transformer status. This innovative arrangement not only enhances the reliability of the detection device, but also provides strong support for transformer maintenance and fault prevention.

[0086] Furthermore, when the packaged micron-sized microdisk resonator 3 is fixed inside the transformer oil tank, when local discharge occurs inside the distribution transformer, a high-frequency acoustic signal of 20kHz to 400kHz will be generated. By receiving the acoustic signal to generate a stress wave that acts on the distributed microdisk resonator array, the time interval and the position information of the microdisk can locate the position information of the local discharge without artifacts.

[0087] In the device provided in this embodiment, the signal acquisition module 5 also includes a host computer. When the electrical signal processed by the photodetector 4 is directly transmitted to the signal acquisition module 5, it is collected and processed by the host computer. This design ensures the accuracy and real-time performance of the data and improves the efficiency and reliability of signal acquisition.

[0088] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0089] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0090] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0091] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0092] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A partial discharge fault detection method based on optical microdisk, characterized in that: include: emitting a laser signal; Adjusting the intensity of the laser signal to obtain an adapted laser signal; coupling an optical signal of a specific wavelength in the adapted laser signal to form a stable standing wave and obtain a first optical signal; The first optical signal is converted into an electrical signal, and the electrical signal is phase-sensitively demodulated to obtain position information of the acoustic signal; and the partial discharge signal is identified and located according to the position information.

2. A partial discharge fault detection method based on an optical microdisk according to claim 1, characterized in that: The method for coupling the optical signal of a specific wavelength in the adapted laser signal is a whispering gallery mode, and the whispering gallery mode includes coupling using a transmission matrix, and the expression of the transmission matrix is: Among them, b0, b1 and b2 are the output port optical energies of different mode lights, a0, a1 and a2 are the input port optical energies of different mode lights, t0, t1 and t2 are the transmission coefficients between different modes, j, k1, k2 and k c is the coupling coefficient between different modes.

3. A partial discharge fault detection method based on an optical microdisk according to claim 1 or 2, characterized in that: In the process of coupling the optical signal of a specific wavelength in the adapted laser signal, there is a phase shift in the coupling between the straight waveguide and the ring waveguide, and different value ranges of the phase shift will change the resonance amplitude.

4. A partial discharge fault detection method based on an optical microdisk according to claim 3, characterized in that: When the phase shift value range is (2m-0.5)π<θ<(2m+0.5)π, the mathematical expression of the resonance amplitude is: Where θ is the phase shift, m is a positive integer, π is the circumference of a circle, j and k c is the coupling coefficient between different modes, t1 and t2 are the transmission coefficients between different modes, b1 and b2 are the output port optical energies of different mode lights, α1 and α2 are the losses of the microdisk resonator, and Phase shift for different whispering gallery modes.

5. The method for detecting partial discharge faults based on an optical microdisk according to claim 3, characterized in that: When the phase shift value range is (2m+0.5)π<θ<(2m+1)π, the mathematical expression of the resonance amplitude is: Where θ is the phase shift, m is a positive integer, π is the circumference of a circle, j and k c is the coupling coefficient between different modes, t1 and t2 are the transmission coefficients between different modes, b1 and b2 are the output port optical energies of different mode lights, α1 and α2 are the losses of the microdisk resonator, and Phase shift for different whispering gallery modes.

6. A partial discharge fault detection method based on an optical microdisk according to claim 4 or 5, characterized in that: The calculation formula for the phase shift of the different whispering gallery modes is: in, is the phase shift of the i-th whispering gallery mode, i is a positive integer greater than zero, π is the circumference of a circle, R is the radius of the microdisk resonator, and n is eff_i is the effective refractive index corresponding to the i-th whispering gallery mode, and λ is the wavelength in vacuum.

7. The method for detecting partial discharge faults based on an optical microdisk according to claim 1, characterized in that: The laser signal is a narrow line width laser signal.

8. A partial discharge fault detection device based on an optical microdisk, characterized in that: include: A tunable laser for emitting a laser signal; an attenuator, connected to the tunable laser by a multimode optical fiber, for adjusting the intensity of the laser signal to obtain an adapted laser signal; at least one micro-disk resonator connected to the attenuator by an optical fiber, and used to couple the optical signal of a specific wavelength in the adapted laser signal to form a stable standing wave and obtain a first optical signal; a photodetector connected to the at least one microdisk resonator using a single-mode optical fiber, and configured to convert the first optical signal into an electrical signal; The signal acquisition module is directly connected to the photoelectric detector and is used to perform phase-sensitive demodulation on the electrical signal to obtain the position information of the acoustic signal.

9. A partial discharge fault detection device based on an optical micro-disk according to claim 8, characterized in that: Each of the microdisk resonators includes a straight waveguide and a polymer cladding.

10. The partial discharge fault detection device based on optical micro-disk according to claim 8, characterized in that: A plurality of the microdisk resonators are distributed at equal intervals on the front and side surfaces of the transformer to form a microdisk resonator array.

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