All-weather power grid equipment abnormal sound monitoring device and sound source positioning method thereof

Abstract

The present application relates to a kind of all-weather power grid equipment abnormal sound monitoring device and its sound source positioning method, belong to the technical field of power equipment online monitoring and fault diagnosis.The device includes: multiple microphone units, each microphone unit includes microphone body and the e-PTFE sound-permeable film covered on its surface, for efficiently permeating sound wave while blocking wind and rain erosion;Multiple three-legged stand poles with water-blocking umbrella covers, at least one microphone unit is arranged on each stand pole, and is distributed around the power grid equipment to be monitored;Data processing unit;And solar power supply module and protection cabin.The method includes: setting loudspeaker array at the suspected abnormal sound source position, using exponential sine sweep method to measure the frequency response function matrix of loudspeaker to microphone unit;After removing the loudspeaker, based on the measured frequency response function matrix and the sound pressure signal collected in real time, the abnormal sound source signal is extracted and the path contribution is calculated using the transfer path analysis method based on regularization.

Description

Technical Field

[0001] This invention belongs to the field of online monitoring and fault diagnosis technology for power equipment, and relates to an all-weather power grid equipment abnormal noise monitoring device and its sound source localization method. Background Technology

[0002] The safe and stable operation of power grid transmission, transformation, and distribution equipment is the core guarantee for reliable power supply in the power system. Abnormal noises generated during equipment operation are often important early warning signals of faults. Monitoring abnormal noises from equipment using acoustic sensors can achieve non-contact fault early warning, which has significant application value.

[0003] Currently, monitoring abnormal noises in power grid equipment mainly relies on acoustic sensors (such as condenser microphones), which have significant technical limitations in outdoor applications. On the one hand, outdoor wind and rain can severely damage microphones; rainwater erosion can easily lead to short circuits in the microphone's internal circuitry and damage to the acquisition unit, while wind interference can cause distortion in the propagation of abnormal noise signals and a decrease in acquisition accuracy. On the other hand, existing microphones struggle to balance sound transmission performance with wind and rain resistance; excessive sealing can lead to severe attenuation of abnormal noise signals, while insufficient sealing cannot withstand wind and rain erosion, resulting in low accuracy in locating abnormal noise sources and delayed fault warnings.

[0004] To address the aforementioned problems, those skilled in the art have proposed several improvements. For example, Chinese patent CN117824826A discloses a real-time substation noise source monitoring method based on multi-channel least squares. This method simulates a noise source by setting up a loudspeaker at the substation envelope, measuring its frequency response function matrix to the noise source monitoring point, and using multi-channel least squares to extract the substation noise source characteristics in real time. While this solution provides a high-precision noise source extraction algorithm, its technical solution is based on the assumption that the microphone itself can work normally in an ideal environment. It does not consider the physical damage and signal interference caused by outdoor wind and rain to the microphone hardware, thus making it difficult to achieve truly stable all-weather operation.

[0005] Furthermore, existing abnormal noise monitoring devices are mostly designed for indoor or ideal environments, and are not specifically adapted to the complex outdoor weather conditions of power grid equipment. They lack a core structure that combines high-efficiency sound transmission and strong weather resistance, and the location of abnormal noise sources often relies on a single microphone, failing to achieve comprehensive coverage and accurate source tracing. Therefore, there is an urgent need for an abnormal noise monitoring device with all-weather weather resistance to overcome the bottleneck of traditional abnormal noise monitoring technology in complex outdoor environments, and to provide technical support for early fault warning of power grid equipment. Summary of the Invention

[0006] In view of this, the present invention aims to solve the technical problem that existing outdoor power grid equipment abnormal noise monitoring devices are unable to balance sound transmission performance and wind and rain resistance, and cannot achieve stable operation in all weather conditions, and provides an all-weather power grid equipment abnormal noise monitoring device and its sound source localization method.

[0007] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides an all-weather power grid equipment abnormal noise monitoring device, comprising: Multiple microphone units, each microphone unit including a microphone body; Multiple poles, each pole having at least one of the aforementioned microphone units installed on it; The data processing unit is connected to the microphone unit; The multiple poles are arranged circumferentially along the power grid equipment to be monitored, and the multiple microphone units form a spatially distributed acoustic array for sound source localization, which is used to collect multi-point sound pressure signals from the radiation surface of the power grid equipment. Each of the microphone units also includes a sound-permeable film covering the surface of the microphone body, the sound-permeable film being used to transmit sound waves while blocking wind and rain erosion. Each of the poles is provided with a water-blocking umbrella at the top, the radius of which is larger than the installation length of the microphone unit, in order to prevent raindrops from directly impacting the microphone unit; The data processing unit is used to: extract abnormal noise source signals based on the multi-point sound pressure signals collected by the spatial distributed acoustic array, combined with the pre-measured frequency response function matrix, and use a regularized transmission path analysis method to calculate the contribution of each transmission path, so as to locate the abnormal noise source of the power grid equipment.

[0008] Preferably, the material of the sound-permeable film is expanded polytetrafluoroethylene (e-PTFE) electronic sound-permeable film, which has a sound pressure transmission coefficient greater than or equal to 0.92 and an insertion loss less than or equal to 0.7 dB in the 50~600 Hz frequency band.

[0009] Preferably, each of the poles is topped with a water-blocking umbrella, the radius of which is larger than the installation length of the microphone unit, to prevent raindrops from directly impacting the microphone unit. The poles are tripod poles, with microphone units evenly spaced on each tripod pole. The poles are arranged around the radiating surface of the power grid equipment to be monitored, and all microphones face and are directly opposite the radiating surface.

[0010] Preferably, the above-mentioned device further includes a solar power supply module and a protective cabin. The solar power supply module is electrically connected to the data processing unit and is used to provide all-weather power supply for the device. The data processing unit and the battery of the solar power supply module are disposed inside the protective cabin.

[0011] Secondly, the present invention provides a method for monitoring abnormal noises in power grid equipment using the above-mentioned device, comprising the following steps: S1. Frequency response function matrix measurement: A loudspeaker array is set up at the suspected abnormal noise source location of the power grid equipment to be monitored, using the same microphone unit layout as during monitoring, and the frequency response function matrix from the loudspeaker array to each microphone unit is measured. S2. Sound source signal extraction: Remove the loudspeaker array, and extract the abnormal noise source signal based on the frequency response function matrix and the sound pressure signal collected in real time by each microphone unit using a regularized transmission path analysis method.

[0012] Preferably, in the frequency response function matrix measurement, the exponential sine sweep frequency method is used to measure the frequency response function matrix, and the exponential sine sweep frequency signal... The characteristics of ) are as follows:

[0013] in, , These are the start and end angular frequencies of the test signal, respectively, and T is the duration of the test signal.

[0014] Preferably, the regularization-based transmission path analysis method includes: Represent the noise source as containing Vector of volume velocity of a point sound source The sound pressure at the receiving point is expressed as including The vector P of the sound pressure at each monitoring point represents the transmission path from the noise source to the receiving point as containing... The matrix G of the frequency response functions; Introducing Tikhonov regularization, by solving... Taking the minimum value of Q as the sound source signal, the solution is:

[0015] in, Let H be the identity matrix, and let H denote the conjugate transpose of the matrix. For the equilibrium matrix, is the regularization coefficient.

[0016] Preferably, the above method further includes S3, path contribution analysis, which calculates the path contribution of each sound source point to each microphone measuring point based on the extracted abnormal noise source signal and the frequency response function matrix, so as to identify the transmission path with prominent abnormal noise.

[0017] Preferably, the sound-permeable film has an error of less than 3dB in the frequency response function measurement within the 50~600Hz frequency band, and the rainy environment has an impact of less than 0.3dB on the sound propagation attenuation in the frequency band below 600Hz within a 50m range.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention effectively solves the problems of rainwater erosion and wind interference by using a dual protection design of encapsulating the microphone with an e-PTFE sound-permeable film and a water-blocking umbrella cover, thus achieving long-term stable operation under harsh outdoor climates. The e-PTFE film has excellent sound transmission performance in the key frequency band of abnormal noise in power grid equipment. Theoretical calculations and experimental verification show that the film coating has no significant impact on the frequency response function measurement, ensuring the accuracy of the subsequent sound source extraction algorithm.

[0019] (2) By combining a distributed microphone array, a precisely measured frequency response function matrix, and a regularized transmission path analysis method, the accurate location of abnormal noise sources and the analysis of their path contributions were achieved. By calculating the path contribution of each noise source, the transmission paths of prominent abnormal noises can be identified, providing accurate data support for early fault warning of power grid equipment.

[0020] (3) This invention forms a complete, scientific, and experimentally supported all-weather monitoring solution from hardware protection, signal acquisition, frequency response measurement to sound source extraction and contribution analysis, effectively overcoming the bottleneck of traditional monitoring technology in complex outdoor environments.

[0021] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0022] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 This is a schematic diagram of the overall deployment of the all-weather power grid equipment abnormal noise monitoring device provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the diaphragm microphone provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the hardware connection of the monitoring device provided in an embodiment of the present invention; Figure 4 This is a comparison chart of the frequency response function amplitudes of uncoated and coated microphones provided in an embodiment of the present invention; Figure 5This is a comparison chart of the frequency response function amplitude of the diaphragm microphone under windless and windy conditions, provided in an embodiment of the present invention. Detailed Implementation

[0023] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0024] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0025] Example 1 provides an all-weather power grid equipment abnormal noise monitoring device for all-weather monitoring and location of abnormal noise sources in power grid equipment such as power distribution equipment.

[0026] like Figure 2 As shown, the core sensor unit of the device employs a microphone encapsulated in a sound-permeable film, comprising a microphone body and a waterproof, sound-permeable film covering the surface of the microphone body. This sound-permeable film possesses both high-efficiency sound transmission and strong resistance to wind and rain. It can block rainwater erosion, prevent short circuits in the microphone's internal circuitry and damage to the acquisition unit, and minimize the attenuation of sound wave signals after passing through the film, effectively isolating signal distortion caused by wind interference.

[0027] In this embodiment, the material of the waterproof and sound-permeable membrane is preferably e-PTFE (expanded polytetrafluoroethylene) electronic sound-permeable membrane. The e-PTFE electronic sound-permeable membrane has a maximum sound loss of no more than 1 dB in the high-frequency range and a loss of 0.5 to 0.7 dB in the low-frequency range of 50 to 600 Hz. This material is extremely thin (thickness less than 0.015 mm) and has a microporous structure; its acoustic impedance is mainly manifested as acoustic resistance, which can be approximated as a constant independent of frequency within the frequency range.

[0028] In other embodiments, the waterproof and acoustically permeable membrane can also be made of other materials with similar acoustic and waterproof properties, such as microporous polypropylene film, Teflon film, etc. When selecting alternative materials, it must be ensured that the insertion loss does not exceed 1dB in the 50-600Hz frequency band and the phase delay is negligible.

[0029] In this embodiment, the overall deployment of this device is as follows: Figure 1 As shown, a distributed layout of tripod poles is adopted, with water-blocking umbrella covers installed on the tripod poles to prevent raindrops from directly impacting the microphones. Each pole serves as a microphone unit, with three sound-permeable film-encapsulated microphones arranged at equal intervals. The three microphone units are arranged around the noise radiation surface of the power distribution equipment, and all microphones face and are directly opposite the radiation surface to achieve all-round coverage of abnormal noises from the equipment.

[0030] In other implementations, for large transformers or converter station equipment, the number of microphone units can be increased to 4-6; for small distribution cabinets, it can be reduced to 2; the number of microphones on each pole can be adjusted to 2-5 according to the equipment height and vertical resolution requirements, and the microphones are arranged at equal intervals; in addition to tripod poles, single-column poles, wall-mounted brackets, etc. can also be used, or existing equipment frames can be used for installation with customized clamps.

[0031] like Figure 3 As shown, a sound-permeable film encapsulates the microphone and speaker, which are directly connected to the sound card. The speaker array simulates various sound sources around the power grid equipment, and the sound card transmits the sound pressure signals collected by the microphone to the computer. The device is powered around the clock by a combination of solar panels and a battery. The sound card, computer, and battery are all housed in a protective enclosure that is waterproof and dustproof, ensuring that the device can accurately capture abnormal noise signals from equipment at different locations and distances in all weather conditions.

[0032] Example 2 details a method for monitoring abnormal noises in power grid equipment using the device described in Example 1.

[0033] (1) Frequency response function matrix measurement Before monitoring power grid equipment, it is necessary to measure the frequency response function matrix. The specific steps are as follows: Loudspeakers should be placed around the suspected source of abnormal noise from the power distribution equipment. The number and location of the loudspeakers can be adjusted according to the size of the equipment and the distribution characteristics of the sound source, but generally no fewer than five are needed to ensure comprehensive coverage of the possible sound source area. The same microphone unit layout used during monitoring should be employed.

[0034] The frequency response function matrix from the loudspeaker to the acoustically transparent diaphragm-encapsulated microphone was measured using the exponential sine sweep method. (Exponential sine sweep signal) The characteristics of ) are as follows:

[0035] in, , These are the start and end angular frequencies of the test signal, respectively, and T is the duration of the test signal.

[0036] For a single loudspeaker-microphone channel, the frequency response function is measured. Measurements are then performed on all loudspeaker and microphone combinations to form a frequency response function matrix. After the measurements are complete, all loudspeakers are removed, and the device enters the normal monitoring phase.

[0037] In other implementations, besides exponential sinusoidal sweep signals, other types of test signals can be used for frequency response function measurement, such as maximum length sequence (MLS) and linear sweep signals. The speaker layout can employ a more systematic grid pattern, with speakers evenly distributed across the equipment envelope, typically spaced 0.5-2 meters apart. The frequency response function matrix can be configured with a periodic update strategy, such as re-measuring quarterly or semi-annually, to correct for changes in transmission characteristics caused by equipment aging or long-term environmental variations.

[0038] (2) Acoustic characteristics analysis of sound-permeable membranes To verify the influence of acoustically permeable films on the measurement of frequency response functions, theoretical analysis and comparative experiments were conducted.

[0039] Microphone output signal when uncoated for:

[0040] in, This is the frequency response function when the film is not applied.

[0041] Microphone output signal during lamination for:

[0042] in, This is the frequency response function when the microphone is diaphragmed.

[0043] In exponential sine sweep frequency measurement, impulse response For output signal and inverse filtered signal Convolution:

[0044] Performing a Fourier transform on both sides yields:

[0045] in, .

[0046] Frequency response when not covered for:

[0047] Frequency response during lamination for:

[0048] in, It is the frequency response function of the sound-permeable film.

[0049] For e-PTFE electronic acoustic membranes, the sound pressure transmission coefficient of sound waves passing through the membrane from air in the 50~600Hz frequency range is... It can be represented as:

[0050] in, For air impedance characteristics, under standard conditions It is the acoustic impedance of the sound-transmitting membrane.

[0051] The formula for calculating the insertion loss of sound waves passing through a membrane from air. for:

[0052] Among them, substituting Calculated Substituting into equation (8), the frequency response function of the sound-permeable membrane is calculated. .

[0053] Phase delay ,in, Take the maximum frequency of 1kHz. Given a film thickness less than 0.015 mm, the phase delay can be calculated. .

[0054] Therefore, the time-frequency response of the coating can be approximately expressed as:

[0055] To verify the above theory, a comparative experiment was conducted. An exponential sine sweep signal (50-500Hz) was emitted through an NSW-050 loudspeaker. An array of microphones with and without acoustically transparent film encapsulation was used as the abnormal noise monitoring points for the two experiments. Both measurements used the same model 4958-A 20kHz 1 / 4-inch TEDS microphone, and the sound card was a MOTU-896mk3. During the experiment, the distance between the loudspeaker and the microphone array was approximately 1.5m.

[0056] Experimental results are as follows Figure 4 As shown, in the amplitude variation curves of the frequency response function at frequencies from 50 to 600 Hz, the FRF (Frequency Response Function) from the loudspeaker to the acoustically transparent film-encapsulated microphone array... ) and speaker to unencapsulated microphone array FRF ( The curves were consistent in shape, with a maximum error of no more than 3dB, verifying that the coating had no significant impact on the frequency response function measurement.

[0057] (3) Environmental Factor Impact Analysis and Verification Since the microphone array's measurement range is no more than 50m, and the frequency of abnormal noise signals from the power grid is concentrated below 600Hz, acoustic studies have shown that the effects of fog, rain, and snow on sound attenuation at this frequency and distance are negligible.

[0058] Compared to sunny weather, rainy weather results in atmospheric absorption loss during sound propagation. The following formula can be used to calculate:

[0059] Air absorption coefficient It depends on frequency, humidity, temperature, and pressure. At a sound frequency of 600Hz, =0.0097dB / m is the air absorption coefficient in rainy conditions; 0.00405 dB / m is the air absorption coefficient under sunny conditions; substituting it into the above formula, we can calculate... =0.283dB, therefore the effect of rainy weather on sound propagation attenuation at this frequency and distance is negligible. The FRF of power grid equipment noise to the microphone array under rainy weather conditions can be approximated as the FRF under clear weather conditions.

[0060] Previous studies have shown that the equivalent continuous sound pressure level of 500-1000Hz measured by a microphone in rainy conditions The noise level will be significantly higher than in sunny conditions, mainly due to vibrations caused by raindrops directly colliding with the microphone, as well as noise generated by collisions with surrounding surfaces. However, transformer radiated noise is primarily low-frequency components below 600Hz. Therefore, most of the noise generated by raindrops and surrounding surfaces is outside the monitoring range of this device, which can automatically filter out noise in this frequency range. Furthermore, by installing a water-blocking umbrella on the top of the tripod, with a radius much larger than the installation length of the diaphragm microphone, this device can significantly reduce the probability of rainwater directly colliding with the diaphragm microphone, protecting the microphone while improving measurement accuracy.

[0061] Besides precipitation factors such as rain, snow, and fog, wind noise (especially low-frequency turbulence) is another major interference factor for outdoor monitoring. Because the microphone is encapsulated with a waterproof and sound-permeable membrane, its microporous structure can block some of the airflow from directly impacting the microphone diaphragm, reducing vibration noise caused by turbulence and playing a basic role in wind protection.

[0062] To measure the impact of wind noise on the frequency response function, a comparative experiment was designed: a large electric fan simulated a wind noise environment, and an exponential sinusoidal sweep signal (50-600Hz) was emitted by an NSW-050 loudspeaker. The signal was acquired by a 4958-A type 20kHz 1 / 4-inch TEDS microphone using a MOTU-896mk3 sound card. During the experiment, the loudspeaker was approximately 1.2m away from the microphone array, and the maximum wind speed was 3.51m / s. The frequency response function from the loudspeaker to the diaphragm microphone array was measured in two experiments under windless conditions. Frequency response function of loudspeaker to diaphragm microphone array under wind noise conditions .

[0063] Experimental results are as follows Figure 5 As shown in the curves, the amplitude variation of the frequency response function at various frequencies from 50 to 600 Hz is... and The curves are consistent in shape, with a maximum error of no more than 3dB, verifying that wind noise has no significant impact on the frequency response function measurement of this device.

[0064] After measuring the frequency response function matrix and removing the loudspeakers, the device enters the real-time monitoring phase. The diaphragm microphone array collects the sound pressure signal radiated by the power grid equipment during operation in real time, converts it into a digital signal via a sound card, and transmits it to the computer. A Fourier transform is performed on the time-domain signal to obtain the sound pressure spectrum vector. Since this device ensures that the measured FRF remains essentially unchanged in windy and rainy environments and under the protection of the waterproof and sound-permeable membrane compared to sunny weather, the multi-channel least squares method can be used to extract the sound source signal. Based on the measured frequency response matrix and the target sound pressure signal of the microphone array, a regularized transmission path analysis method is used to extract the sound source signal.

[0065] (4) Sound source signal extraction An array of sound-permeable film-encapsulated microphones and various sound source points were rationally arranged around the power grid. After measuring the FRF of the power grid equipment noise to the film-encapsulated microphones, the noise sources were analyzed using a combination of sound-permeable film-encapsulated microphones. The volume velocity of a point sound source is represented by a vector. This indicates that the receiving point uses a method that includes... The sound pressure at each monitoring point is represented by a vector. This indicates that the transmission path from the noise source to the receiving point uses a method that includes... The matrix of the frequency response function FRF This indicates that in the field of multi-point sound field reproduction, a Tikhonov-regularized multi-channel least squares method is introduced to extract more accurate sound source signals. The multi-channel least squares method extracts sound sources around the power grid. , take When it is the minimum value To find the solution, the solution is:

[0066] in, Let H be the identity matrix, and let H denote the conjugate transpose of the matrix. For the equilibrium matrix, The regularization coefficient can be selected using the L-curve method.

[0067] Example 3 illustrates a typical application scenario after integrating the solutions described in the above examples into a system.

[0068] The components described in Example 1 are integrated to form a complete monitoring system. Solar panels are installed at or near the top of the protective cabin to ensure sufficient sunlight. The cabin houses a sound card, computer, solar cells, and necessary temperature control equipment. All external interfaces are waterproofed to ensure an IP65 or higher protection rating. The computer is pre-installed with signal processing software to perform the following functions: data acquisition and storage; frequency response function calculation and management; real-time sound pressure spectrum analysis; sound source signal extraction and path contribution calculation; abnormal alarms and remote data transmission.

[0069] Scenario 1: Transformer Abnormal Noise Monitoring: Three microphone units are arranged around the transformer, facing its three sides respectively. Three diaphragm microphones are mounted on each pole, arranged vertically at equal intervals, covering the entire height of the transformer. After completing the FRF measurement, the device enters 24-hour continuous monitoring.

[0070] When a loose winding occurs inside the transformer, the system extracts the abnormal sound source signal in real time and calculates the contribution of each path. Data shows that the abnormal sound source is located near the A-phase bushing at the top of the transformer, contributing 45% of the signal, providing maintenance personnel with accurate fault location information.

[0071] Scenario 2: Monitoring Abnormal Noise from GIS Equipment: Due to the complex structure and varied locations of sound sources in GIS equipment, the number of microphone units can be increased to 4-5, arranged around the equipment. During FRF measurement, loudspeakers are placed in multiple air chambers and operating mechanisms of the GIS, using a grid layout to ensure comprehensive coverage.

[0072] When an abnormal noise is generated during the operation of the disconnecting switch, the system can capture the transient sound signal in real time. After extracting the sound source signal, it can be determined that the source of the abnormal noise is a contact of a certain disconnecting switch, which accounts for 60% of the noise. This provides an early warning that there may be a risk of contact burning.

[0073] Scenario 3: Reactor Noise Monitoring: Dry-type reactors often produce abnormal noises due to inter-turn short circuits during operation. Three microphone units are placed around the reactor, providing full coverage. The system continuously monitors the radiated acoustic signal from the reactor. When an inter-turn short circuit occurs, high-order harmonic components appear in the signal spectrum. The system extracts the sound source signal and calculates its contribution, locating the anomaly in the upper middle part of the reactor, where the contribution accounts for 52%. This timely warning prevents the fault from escalating.

[0074] In summary, this invention, through the dual protection design of a microphone encapsulated in an e-PTFE sound-permeable film and a water-blocking umbrella, combined with a sound source extraction method based on regularized transmission path analysis, achieves all-weather accurate monitoring and location of abnormal noises in power grid equipment, providing reliable technical support for early warning of equipment faults.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A 24 / 7 power grid equipment abnormal noise monitoring device, characterized in that, include: Multiple microphone units, each microphone unit including a microphone body; Multiple poles, each pole having at least one of the aforementioned microphone units installed on it; The data processing unit is connected to the microphone unit; The multiple poles are arranged circumferentially along the power grid equipment to be monitored, and the multiple microphone units form a spatially distributed acoustic array for sound source localization, which is used to collect multi-point sound pressure signals from the radiation surface of the power grid equipment. Each of the microphone units also includes a sound-permeable film covering the surface of the microphone body, the sound-permeable film being used to transmit sound waves while blocking wind and rain erosion. Each of the poles is provided with a water-blocking umbrella at the top, the radius of which is larger than the installation length of the microphone unit, in order to prevent raindrops from directly impacting the microphone unit; The data processing unit is used to: extract abnormal noise source signals based on the multi-point sound pressure signals collected by the spatial distributed acoustic array, combined with the pre-measured frequency response function matrix, and use a regularized transmission path analysis method to calculate the contribution of each transmission path, so as to locate the abnormal noise source of the power grid equipment.

2. The apparatus according to claim 1, characterized in that, The sound-permeable membrane is made of expanded polytetrafluoroethylene (e-PTFE) electronic sound-permeable membrane with a thickness of less than 0.015 mm, a sound pressure transmission coefficient greater than or equal to 0.92 in the 50~600 Hz frequency band, and an insertion loss of less than or equal to 0.7 dB.

3. The apparatus according to claim 1, characterized in that, The pole is a tripod pole, and each tripod pole is equipped with microphone units at equal intervals. The pole is arranged around the radiation surface of the power grid equipment to be monitored, and all microphones face and are directly opposite the radiation surface.

4. The apparatus according to claim 1, characterized in that, It also includes a solar power module and a protective cabin. The solar power module is electrically connected to the data processing unit and is used to provide all-weather power to the device. The data processing unit and the battery of the solar power module are housed in the protective cabin.

5. A method for monitoring abnormal noises in power grid equipment using the device described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Frequency response function matrix measurement: A loudspeaker array is set up at the suspected abnormal noise source location of the power grid equipment to be monitored, using the same microphone unit layout as during monitoring, and the frequency response function matrix from the loudspeaker array to each microphone unit is measured. S2. Sound source signal extraction: Remove the loudspeaker array, and extract the abnormal noise source signal based on the frequency response function matrix and the sound pressure signal collected in real time by each microphone unit using a regularized transmission path analysis method.

6. The method according to claim 5, characterized in that, In the frequency response function matrix measurement, the exponential sine sweep frequency method is used to measure the frequency response function matrix, and the exponential sine sweep frequency signal... The characteristics of ) are as follows: in, , These are the start and end angular frequencies of the test signal, respectively, and T is the duration of the test signal.

7. The method according to claim 5, characterized in that, The regularization-based transmission path analysis method includes: Represent the noise source as containing Vector of volume velocity of a point sound source The sound pressure at the receiving point is expressed as including The vector P of the sound pressure at each monitoring point represents the transmission path from the noise source to the receiving point as containing... The matrix G of the frequency response functions; Introducing Tikhonov regularization, by solving... Taking the minimum value of Q as the sound source signal, the solution is: in, Let H be the identity matrix, and let H denote the conjugate transpose of the matrix. For the equilibrium matrix, is the regularization coefficient.

8. The method according to claim 5, characterized in that, It also includes path contribution analysis: based on the extracted abnormal noise source signals and the frequency response function matrix, the path contribution of each sound source point to each microphone measurement point is calculated to identify the transmission path with prominent abnormal noise.

9. The method according to claim 5, characterized in that, The sound-permeable film has an error of less than 3dB in the frequency response function measurement within the 50~600Hz frequency band, and the rainy environment has an impact of less than 0.3dB on the sound propagation attenuation in the frequency band below 600Hz within a 50m range.

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