Method and device for detecting local electric leakage of power equipment

Abstract

The invention provides a power equipment local electric leakage detection method and device, and belongs to the technical field of local electric leakage detection, and the method comprises the steps: obtaining a vibration signal, collected based on a grating array vibration sensing optical cable, of power equipment and a sound wave signal, collected based on a grating array sound wave sensing optical cable, of the power equipment; constructing a sound wave intensity probability distribution diagram based on the sound wave signal, and determining a target signal width based on the sound wave intensity probability distribution diagram; determining a first local electric leakage detection result based on the target signal width; performing wavelet packet decomposition on the vibration signal based on a preset wavelet basis to obtain a plurality of signal frequency bands, and determining a second local electric leakage detection result based on the plurality of signal frequency bands; and when the first local electric leakage detection result and the second local electric leakage detection result are the same, taking the first local electric leakage detection result or the second local electric leakage detection result as a final local electric leakage detection result. According to the invention, the detection accuracy of detecting the local electric leakage of the power equipment is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of local leakage detection, and in particular to a method and device for detecting local leakage of electric equipment. Background Art

[0002] Local leakage is the main cause of insulation degradation and damage of power equipment. Strong local leakage will cause the insulation strength to drop rapidly. Therefore, it is of great significance to conduct online detection of local leakage of large power equipment.

[0003] Currently, the common method for local leakage detection is the UHF method. However, the UHF method will be affected by the gas composition and is greatly affected by the electromagnetic noise in the environment, which leads to high requirements for the detection environment. Therefore, the acoustic wave method is called the mainstream detection method, but the acoustic wave has defects such as low reliability and large errors.

[0004] Therefore, there is an urgent need to provide a method and device for detecting local leakage of electric equipment, so as to improve the accuracy of detecting local leakage of electric equipment. Summary of the invention

[0005] In view of this, it is necessary to provide a method and device for detecting local leakage of electric equipment, so as to solve the technical problem of low accuracy of local leakage detection of electric equipment existing in the prior art.

[0006] On the one hand, in order to solve the above technical problems, the present invention provides a method for detecting local leakage of electric equipment, comprising: Acquire vibration signals of electric power equipment collected by grating array vibration sensing optical cables and acoustic wave signals of electric power equipment collected by grating array acoustic wave sensing optical cables; constructing a sound wave intensity probability distribution graph based on the sound wave signal, and determining a target signal width based on the sound wave intensity probability distribution graph; determining a first local leakage detection result based on the target signal width; Performing wavelet packet decomposition on the vibration signal based on a preset wavelet basis to obtain a plurality of signal frequency bands, and determining a second local leakage detection result based on the plurality of signal frequency bands; When the first local leakage detection result and the second local leakage detection result are the same, the first local leakage detection result or the second local leakage detection result is used as the final local leakage detection result.

[0007] In a possible implementation, the sound wave signal includes a plurality of sound wave sub-signals with different sound wave intensities; then the step of constructing a sound wave intensity probability distribution graph based on the sound wave signal includes: Dividing the sound wave intensity into a plurality of sound wave intensity intervals, and determining a statistical number of sound wave sub-signals in each sound wave intensity interval; The total number of signals in the sound wave signal is obtained, the ratio of the statistical number to the total number of signals is used as the sound wave intensity probability distribution, and the sound wave intensity probability distribution graph is constructed based on the sound wave intensity probability distribution.

[0008] In a possible implementation manner, determining the target signal width based on the sound wave intensity probability distribution graph includes: Determining a maximum signal strength based on the acoustic wave strength probability distribution graph; Taking the maximum signal strength as the center and expanding toward both ends with a preset step length, determining the strength accumulation probability within the expansion range; A target extension range is determined based on the intensity cumulative probability, and a signal width of the target extension range is used as the target signal width.

[0009] In a possible implementation manner, determining a first local leakage detection result based on the target signal width includes: Determining whether the target signal width is less than a signal width threshold; When the target signal width is smaller than the signal width threshold, the first local leakage detection result is that local leakage exists.

[0010] In a possible implementation manner, determining a second local leakage detection result based on the multiple signal frequency bands includes: Dividing the plurality of signal frequency bands into a plurality of low signal frequency bands and the plurality of high signal frequency bands, and determining a low signal energy sum of the plurality of low signal frequency bands and a high signal energy sum of the plurality of high signal frequency bands; determining an energy ratio of the low signal energy sum to the high signal energy sum; It is determined whether the energy ratio is greater than an energy ratio threshold. If so, the second local leakage detection result is that local leakage exists.

[0011] In a possible implementation, the method further includes: When the final local leakage detection result is that there is local leakage, determining a first local leakage position based on the sound wave signal, and determining a second local leakage position based on the vibration signal; It is determined whether the position difference between the first local leakage position and the second local leakage position is less than a preset difference value. If so, the first local leakage position or the second local leakage position is used as the final local leakage position.

[0012] In a possible implementation, the grating array acoustic wave sensor optical cable includes a plurality of acoustic wave sensors, and the acoustic wave signal includes a plurality of acoustic wave sub-signals corresponding one-to-one to the plurality of acoustic wave sensors; then determining the first local leakage position based on the acoustic wave signal includes: Performing wavelet denoising on the multiple sound wave sub-signals to obtain multiple denoised sub-signals; Performing Fourier transform on the multiple denoised sub-signals to obtain multiple Fourier transform signals; Performing convolution processing on any two of the Fourier transform signals to obtain a signal cross power spectrum; Performing inverse Fourier transform on the signal cross power spectrum to obtain a cross correlation coefficient; The first local leakage position is determined based on the cross-correlation coefficient.

[0013] In a possible implementation, the grating array vibration sensing optical cable includes a plurality of vibration sensors, and the vibration signal includes a plurality of vibration sub-signals corresponding one-to-one to the plurality of vibration sensors; then determining the second local leakage position based on the vibration signal includes: Determining the short-time energy of each of the vibration sub-signals based on a short-time energy algorithm; When the short-time energy is greater than an energy threshold, it is determined that local leakage occurs at the vibration sensor position corresponding to the short-time energy, and the second local leakage position is determined based on the position of the vibration sensor.

[0014] In a possible implementation, after obtaining the vibration signal of the power equipment collected by the grating array vibration sensing optical cable and the acoustic wave signal of the power equipment collected by the grating array acoustic wave sensing optical cable, the method further includes: The vibration signal and the sound wave signal are subjected to noise reduction processing respectively.

[0015] On the other hand, the present invention also provides a local leakage detection device for electric equipment, comprising: A signal acquisition unit, used to acquire a vibration signal of the power equipment collected by the grating array vibration sensing optical cable and an acoustic wave signal of the power equipment collected by the grating array acoustic wave sensing optical cable; an acoustic wave signal analysis unit, configured to construct an acoustic wave intensity probability distribution diagram based on the acoustic wave signal, and determine a target signal width based on the acoustic wave intensity probability distribution diagram; A first local leakage detection unit, configured to determine a first local leakage detection result based on the target signal width; a second local leakage detection unit, configured to perform wavelet packet decomposition on the vibration signal based on a preset wavelet basis to obtain a plurality of signal frequency bands, and determine a second local leakage detection result based on the plurality of signal frequency bands; The final local leakage detection unit is used to use the first local leakage detection result or the second local leakage detection result as the final local leakage detection result when the first local leakage detection result and the second local leakage detection result are the same.

[0016] The beneficial effects of the present invention are as follows: the local leakage detection method for electric power equipment provided by the present invention obtains two different types of grating array sensor signals, namely vibration signals and sound wave signals, and analyzes the sound wave signals and vibration signals respectively to obtain a corresponding first local leakage detection result and a second local leakage detection result, and finally determines the final local leakage detection result based on the first local leakage detection result and the second local leakage detection result, thereby solving the technical problem of unreliable and inaccurate results when local leakage judgment is performed based on a single sound wave signal or other signal, and improving the accuracy of the local leakage results.

[0017] Furthermore, since the grating array vibration sensor optical cable and the grating array acoustic wave sensor optical cable are continuous array gratings prepared on a large scale using a drawing tower, they have the advantages of multiple measuring points, large capacity, high sensitivity and long distance. Therefore, they can achieve full-area detection of power equipment, further improving the comprehensiveness and accuracy of local leakage detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 A schematic diagram of a flow chart of an embodiment of a method for detecting partial leakage of electric equipment provided by the present invention; Figure 2 For the present invention Figure 1 A schematic diagram of an embodiment of a flow chart of constructing a probability distribution diagram of sound wave intensity in step S102; Figure 3 For the present invention Figure 1 A schematic diagram of an embodiment of determining the target signal width in step S102; Figure 4 For the present invention Figure 1 A schematic flow chart of an embodiment of determining a second local leakage detection result in step S104; Figure 5 A schematic diagram of a flow chart of an embodiment of determining a local leakage position provided by the present invention; Figure 6 For the present invention Figure 5A schematic diagram of an embodiment of a flow chart for determining a first local leakage position in step S501; Figure 7 For the present invention Figure 5 A schematic diagram of an embodiment of a flow chart for determining a second local leakage position in step S501; Figure 8 A schematic structural diagram of an embodiment of a local leakage detection device for electric equipment provided by the present invention. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0021] It should be understood that the schematic drawings are not drawn to scale. The flowchart used in the present invention shows the operations implemented according to some embodiments of the present invention. It should be understood that the operations of the flowchart can be implemented out of order, and the steps without logical context can be reversed in order or implemented simultaneously. In addition, those skilled in the art, under the guidance of the content of the present invention, can add one or more other operations to the flowchart, and can also remove one or more operations from the flowchart. Some of the block diagrams shown in the accompanying drawings are functional entities, which do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor systems and / or microcontroller systems.

[0022] Reference to an "embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0023] The present invention provides a method and device for detecting local leakage of electric equipment, which are described below respectively.

[0024] Figure 1 A schematic diagram of an embodiment of a method for detecting partial leakage of electric power equipment provided by the present invention is shown in FIG. Figure 1 As shown, the local leakage detection method of power equipment includes: S101, obtaining a vibration signal of the electric power equipment collected by a grating array vibration sensing optical cable and an acoustic wave signal of the electric power equipment collected by a grating array acoustic wave sensing optical cable; S102, constructing a sound wave intensity probability distribution map based on the sound wave signal, and determining a target signal width based on the sound wave intensity probability distribution map; S103, determining a first local leakage detection result based on a target signal width; S104, performing wavelet packet decomposition on the vibration signal based on a preset wavelet basis to obtain multiple signal frequency bands, and determining a second local leakage detection result based on the multiple signal frequency bands; S105. When the first local leakage detection result and the second local leakage detection result are the same, use the first local leakage detection result or the second local leakage detection result as the final local leakage detection result.

[0025] The power equipment in the embodiment of the present invention includes but is not limited to power switches and cables.

[0026] It should be understood that before executing the local leakage detection method for electric power equipment proposed in the embodiment of the present invention, the grating array vibration sensor optical cable and the grating array acoustic wave sensor optical cable need to be laid in the electric power equipment.

[0027] It should be noted that: in step S105, when the first local leakage detection result and the second local leakage detection result are different, the detection is performed again, that is, steps S101 to S105 are executed again.

[0028] The preset wavelet basis in step S104 can be selected from Haar, Daubechies, Biothogonal and other wavelet bases according to the needs. In some embodiments of the present invention, the preset wavelet basis is the db3 wavelet basis in Daubechies, and the wavelet packet decomposition of the vibration signal based on the preset wavelet basis in step S104 is specifically as follows: Based on the db3 wavelet basis, the vibration signal is decomposed into 16 signal frequency bands by 4-layer wavelet packet decomposition, namely f1, f2, f3, f4, f5, f6, f7, f8, f9, f 10 、f 11 、f 12 、f 13 、f 14 、f 15 、f 16 .

[0029] Compared with the prior art, the local leakage detection method for electric power equipment provided in the embodiment of the present invention obtains two different types of grating array sensor signals, namely vibration signals and sound wave signals, and analyzes the sound wave signals and vibration signals respectively to obtain a corresponding first local leakage detection result and a second local leakage detection result. Finally, the final local leakage detection result is determined based on the first local leakage detection result and the second local leakage detection result, thereby solving the technical problem of unreliable and inaccurate results when local leakage judgment is based on a single sound wave signal or other signal, and improving the accuracy of the local leakage results.

[0030] Furthermore, since the grating array vibration sensor optical cable and the grating array acoustic wave sensor optical cable are continuous array gratings prepared on a large scale using a drawing tower, they have the advantages of multiple measuring points, large capacity, high sensitivity and long distance. Therefore, they can achieve full-area detection of power equipment, further improving the comprehensiveness and accuracy of local leakage detection.

[0031] In some embodiments of the present invention, the sound wave signal includes a plurality of sound wave sub-signals with different sound wave intensities; Figure 2 As shown, constructing a sound wave intensity probability distribution diagram based on the sound wave signal in step S102 includes: S201, dividing the sound wave intensity into a plurality of sound wave intensity intervals, and determining the statistical number of sound wave sub-signals in each sound wave intensity interval; S202: Obtain the total number of signals in the sound wave signal, use the ratio of the statistical number to the total number of signals as the sound wave intensity probability distribution, and construct a sound wave intensity probability distribution graph based on the sound wave intensity probability distribution.

[0032] When there is no local leakage in the power equipment, the ratio of the statistical quantity in each sound wave intensity interval to the total number of signals will not be very different, that is, the sound wave intensity probability distribution diagram will not have an obvious peak. Therefore, the embodiment of the present invention can determine whether there is a local leakage in the power equipment through the sound wave intensity probability distribution diagram.

[0033] The intensity of the sound wave sub-signal depends on the intensity range and the signal acquisition accuracy. For example, when the intensity range is 0-99dB and the signal acquisition accuracy is 1dB, the sound wave intensities of the multiple sound wave sub-signals are 0, 1, ..., 99dB.

[0034] Among them, the total number of signals is not only related to the intensity range and signal acquisition accuracy, but also to the number of signal acquisition times.

[0035] It should be understood that the narrower the sound wave intensity range, the more accurate the detection result. In actual applications, the size of the sound wave intensity range can be set based on actual application scenarios or empirical values.

[0036] In some embodiments of the present invention, Figure 3 As shown, determining the target signal width based on the sound wave intensity probability distribution diagram in step S102 includes: S301, determining the maximum signal strength based on the sound wave strength probability distribution diagram; S302, taking the maximum signal strength as the center and extending to both ends with a preset step length, and determining the strength accumulation probability within the extended range; S303: Determine a target extension range based on the intensity cumulative probability, and use the signal width of the target extension range as the target signal width.

[0037] The maximum signal strength in step S301 refers to the sound wave signal strength corresponding to the maximum value of the sound wave intensity probability distribution.

[0038] The intensity cumulative probability in step S302 is the sum of the probability distributions of the sound wave intensities corresponding to the sound wave intensities when expanding toward both ends.

[0039] It should be understood that step S303 specifically includes: determining whether the intensity cumulative probability is greater than the cumulative probability threshold, and if so, the extension range corresponding to the intensity cumulative probability at this time is the target extension range. The target signal width refers to the total number of sound wave intensities in the target extension range.

[0040] In some embodiments of the present invention, step S103 is specifically: Determine whether the target signal width is less than the signal width threshold; When the target signal width is smaller than the signal width threshold, the first local leakage detection result is that local leakage exists.

[0041] This is because: compared with the sound wave signal without leakage, the width of the sound wave signal with leakage is narrower, so the embodiment of the present invention can accurately detect local leakage by setting a signal width threshold to determine whether local leakage occurs.

[0042] It should be understood that the signal width threshold value can be adjusted according to specific circumstances. The larger the value, the higher the sensitivity to the local leakage signal and the higher the detection accuracy.

[0043] In some embodiments of the present invention, Figure 4 As shown, determining the second local leakage detection result based on multiple signal frequency bands in step S104 includes: S401, dividing a plurality of signal frequency bands into a plurality of low signal frequency bands and a plurality of high signal frequency bands, and determining a sum of low signal energies of the plurality of low signal frequency bands and a sum of high signal energies of the plurality of high signal frequency bands; S402, determining an energy ratio of the low signal energy sum to the high signal energy sum; S403, determining whether the energy ratio is greater than an energy ratio threshold value, and if so, the second local leakage detection result is that local leakage exists.

[0044] Since the proportion of energy in the low frequency band increases significantly when local leakage occurs in the electrical equipment, the embodiment of the present invention can accurately determine the second local leakage result through the energy ratio of the low signal energy sum to the high signal energy sum.

[0045] To avoid ultra-low frequency noise interference, in some embodiments of the present invention, before step S401, ultra-low frequency bands in multiple signal frequency bands are eliminated, and then steps S401 to S403 are performed on the remaining signal frequency bands to improve the detection accuracy of local leakage.

[0046] In a specific embodiment of the present invention, the frequency range of the vibration signal is 0~12800 Hz, and the 16 signal frequency bands f1~f 16 0~800Hz, 800~1600Hz,...,12000~12800Hz respectively, then the energy ratio is: (f3+f4+f5+f6) / (f3+f4+f5+f6,...,+f 16 ).

[0047] In a specific embodiment of the present invention, the energy ratio threshold is 35%.

[0048] In actual application scenarios, when it is determined that there is a local leakage in the power equipment, the maintenance personnel need to know the local leakage location and deal with the local leakage location in time. Therefore, in some embodiments of the present invention, Figure 5 As shown, the method for detecting local leakage of electric equipment also includes: S501, when the final local leakage detection result is that there is local leakage, determining a first local leakage position based on the sound wave signal, and determining a second local leakage position based on the vibration signal; S502: Determine whether the position difference between the first local leakage position and the second local leakage position is less than a preset difference value; if so, take the first local leakage position or the second local leakage position as the final local leakage position.

[0049] Similarly, when determining the final local leakage position, the embodiment of the present invention determines the first local leakage position based on the sound wave signal and determines the second local leakage position based on the vibration signal, respectively, which can ensure the accuracy of the determined final local leakage position.

[0050] In some embodiments of the present invention, the grating array acoustic wave sensor optical cable includes a plurality of acoustic wave sensors, and the acoustic wave signal includes a plurality of acoustic wave sub-signals corresponding one-to-one to the plurality of acoustic wave sensors; Figure 6As shown, determining the first local leakage position based on the acoustic wave signal in step S501 includes: S601, performing wavelet denoising on a plurality of sound wave sub-signals to obtain a plurality of denoised sub-signals; S602, performing Fourier transform on the multiple denoised sub-signals to obtain multiple Fourier transform signals; S603, performing convolution processing on any two Fourier transform signals to obtain a signal cross power spectrum; S604, performing inverse Fourier transform on the signal cross power spectrum to obtain a cross correlation coefficient; S605: Determine a first local leakage position based on the mutual correlation coefficient.

[0051] Since the cross-correlation coefficient at the location where the local leakage occurs will have a peak value, the embodiment of the present invention can determine the first local leakage location by determining the cross-correlation coefficient at the location.

[0052] The basic principle of wavelet denoising in step S601 is: orthogonal wavelet decomposition has the ability of local time-frequency decomposition. When processing signals, the amplitude of wavelet components is relatively large, which forms a clear contrast with the uniform performance of noise in the high-frequency part. After wavelet decomposition, the wavelet coefficients with relatively large amplitudes are useful signals, while the coefficients with relatively small amplitudes are noises, that is, it can be considered that the wavelet transform coefficients of useful signals are greater than the wavelet transform coefficients of noises. Finding a suitable threshold and retaining the wavelet coefficients greater than the threshold can achieve wavelet denoising.

[0053] Step S605 specifically includes: determining the maximum mutual correlation coefficient among the mutual correlation coefficients, determining the acoustic wave sensor corresponding to the maximum mutual correlation coefficient, and taking the spatial position of the acoustic wave sensor as the first local leakage position.

[0054] In some embodiments of the present invention, the grating array vibration sensing optical cable includes a plurality of vibration sensors, and the vibration signal includes a plurality of vibration sub-signals corresponding to the plurality of vibration sensors one by one; Figure 7 As shown, determining the second local leakage position based on the vibration signal in step S501 includes: S701, determining the short-time energy of each vibration sub-signal based on a short-time energy algorithm; S702: When the short-time energy is greater than the energy threshold, determine that local leakage occurs at the vibration sensor position corresponding to the short-time energy, and determine a second local leakage position based on the position of the vibration sensor.

[0055] When local leakage occurs in the electrical equipment, the short-time energy at the local leakage location is much greater than the short-time energy at the location where no local leakage occurs. Therefore, the embodiment of the present invention can determine the second local leakage location based on the short-time energy.

[0056] Since the electrical equipment generates sound and vibration during operation, the vibration signal and the sound wave signal obtained in step S101 are necessarily mixed with other noise signals. In order to avoid the influence of the noise signal on the detection result, in some embodiments of the present invention, after step S101, the following steps are further included: The vibration signal and the sound wave signal are subjected to noise reduction processing respectively.

[0057] The noise reduction process may be: based on a bandpass filter, a high-pass filter, an amplifier and the like, to remove part of the noise.

[0058] In a preferred embodiment of the present invention, the noise reduction processing of the vibration signal also includes: reconstructing the vibration signal through the phase space to obtain a high-dimensional phase space matrix, using the high-dimensional phase space matrix as the input of the independent component analysis method, performing signal-noise separation on the high-dimensional space, outputting a series of independent components, and classifying the series of independent components obtained after the independent component analysis method is processed to obtain estimated source information components and noise information components; selecting the estimated source information component, reconstructing the vibration signal, and eliminating the noise in the vibration signal.

[0059] In a preferred embodiment of the present invention, the noise reduction processing of the sound wave signal also includes: calculating the autocorrelation function of the sound wave signal, judging whether the sound wave signal includes a periodic signal, and if the sound wave signal includes a periodic signal, filtering out the periodic signal by a multi-stage filtering method; performing EMD decomposition on the sound wave signal from which the periodic signal is filtered out to obtain a series of IMF components, and judging whether the IMF components contain mutation signals, and if the IMF components contain mutation signals, discarding a part of the IMF components that do not contain mutation signals; calculating the mutual correlation coefficient between the remaining IMF components and the original signal after discarding a part of the IMF components that do not contain mutation signals, and discarding the IMF components with small mutual correlation coefficients; performing noise reduction processing on the IMF components after discarding the mutual correlation coefficients, and reconstructing the IMF components after the noise reduction processing to obtain a pure sound wave signal.

[0060] In order to better implement the local leakage detection method of the electric equipment in the embodiment of the present invention, based on the local leakage detection method of the electric equipment, the embodiment of the present invention also provides a local leakage detection device of the electric equipment, such as Figure 8 As shown, the local leakage detection device 800 for electric power equipment includes: The signal acquisition unit 801 is used to acquire the vibration signal of the power equipment collected by the grating array vibration sensing optical cable and the acoustic wave signal of the power equipment collected by the grating array acoustic wave sensing optical cable; The acoustic wave signal analysis unit 802 is used to construct an acoustic wave intensity probability distribution map based on the acoustic wave signal, and determine the target signal width based on the acoustic wave intensity probability distribution map; A first local leakage detection unit 803, configured to determine a first local leakage detection result based on a target signal width; A second local leakage detection unit 804 is used to perform wavelet packet decomposition on the vibration signal based on a preset wavelet basis to obtain multiple signal frequency bands, and determine a second local leakage detection result based on the multiple signal frequency bands; The final local leakage detection unit 805 is configured to use the first local leakage detection result or the second local leakage detection result as the final local leakage detection result when the first local leakage detection result and the second local leakage detection result are the same.

[0061] It should be noted that the local leakage detection device 800 for electric equipment provided in the above embodiment can implement the technical solution described in the above embodiment of the local leakage detection method for electric equipment. The specific implementation principles or specific implementation details of the above modules or units can refer to the corresponding contents in the above embodiment of the local leakage detection method for electric equipment, which will not be described one by one here.

[0062] Those skilled in the art will appreciate that all or part of the processes of the above-mentioned embodiments can be implemented by instructing related hardware (such as a processor, a controller, etc.) through a computer program, and the computer program can be stored in a computer-readable storage medium, wherein the computer-readable storage medium is a disk, an optical disk, a read-only storage memory, or a random access memory, etc.

[0063] The above is a detailed introduction to a method and device for detecting local leakage of electric equipment provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for technical personnel in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A method for detecting local leakage of electric power equipment, characterized in that: include: Acquire vibration signals of electric power equipment collected by grating array vibration sensing optical cables and acoustic wave signals of electric power equipment collected by grating array acoustic wave sensing optical cables; constructing a sound wave intensity probability distribution graph based on the sound wave signal, and determining a target signal width based on the sound wave intensity probability distribution graph; determining a first local leakage detection result based on the target signal width; Performing wavelet packet decomposition on the vibration signal based on a preset wavelet basis to obtain a plurality of signal frequency bands, and determining a second local leakage detection result based on the plurality of signal frequency bands; When the first local leakage detection result and the second local leakage detection result are the same, the first local leakage detection result or the second local leakage detection result is used as the final local leakage detection result.

2. The method for detecting local leakage of electric power equipment according to claim 1, characterized in that: The sound wave signal includes a plurality of sound wave sub-signals with different sound wave intensities; then constructing a sound wave intensity probability distribution diagram based on the sound wave signal includes: Dividing the sound wave intensity into a plurality of sound wave intensity intervals, and determining a statistical number of sound wave sub-signals in each sound wave intensity interval; The total number of signals in the sound wave signal is obtained, the ratio of the statistical number to the total number of signals is used as the sound wave intensity probability distribution, and the sound wave intensity probability distribution graph is constructed based on the sound wave intensity probability distribution.

3. The method for detecting local leakage of electric power equipment according to claim 2, characterized in that: The determining of the target signal width based on the sound wave intensity probability distribution diagram comprises: Determining a maximum signal strength based on the acoustic wave strength probability distribution graph; Taking the maximum signal strength as the center and expanding toward both ends with a preset step length, determining the strength accumulation probability within the expansion range; A target extension range is determined based on the intensity cumulative probability, and a signal width of the target extension range is used as the target signal width.

4. The method for detecting local leakage of electric power equipment according to claim 1, characterized in that: The determining a first local leakage detection result based on the target signal width includes: Determining whether the target signal width is less than a signal width threshold; When the target signal width is smaller than the signal width threshold, the first local leakage detection result is that local leakage exists.

5. The method for detecting local leakage of electric power equipment according to claim 1, characterized in that: The determining a second local leakage detection result based on the multiple signal frequency bands comprises: Dividing the plurality of signal frequency bands into a plurality of low signal frequency bands and the plurality of high signal frequency bands, and determining a low signal energy sum of the plurality of low signal frequency bands and a high signal energy sum of the plurality of high signal frequency bands; determining an energy ratio of the low signal energy sum to the high signal energy sum; It is determined whether the energy ratio is greater than an energy ratio threshold. If so, the second local leakage detection result is that local leakage exists.

6. The method for detecting partial leakage of electric power equipment according to claim 1, characterized in that: The method further comprises: When the final local leakage detection result is that there is local leakage, determining a first local leakage position based on the sound wave signal, and determining a second local leakage position based on the vibration signal; It is determined whether the position difference between the first local leakage position and the second local leakage position is less than a preset difference value. If so, the first local leakage position or the second local leakage position is used as the final local leakage position.

7. The method for detecting partial leakage of electric power equipment according to claim 6, characterized in that: The grating array acoustic wave sensor optical cable includes a plurality of acoustic wave sensors, and the acoustic wave signal includes a plurality of acoustic wave sub-signals corresponding one-to-one to the plurality of acoustic wave sensors; then determining the first local leakage position based on the acoustic wave signal includes: Performing wavelet denoising on the multiple sound wave sub-signals to obtain multiple denoised sub-signals; Performing Fourier transform on the multiple denoised sub-signals to obtain multiple Fourier transform signals; Performing convolution processing on any two of the Fourier transform signals to obtain a signal cross power spectrum; Performing inverse Fourier transform on the signal cross power spectrum to obtain a cross correlation coefficient; The first local leakage position is determined based on the cross-correlation coefficient.

8. The method for detecting partial leakage of electric power equipment according to claim 6, characterized in that: The grating array vibration sensing optical cable includes a plurality of vibration sensors, and the vibration signal includes a plurality of vibration sub-signals corresponding to the plurality of vibration sensors one by one; then determining the second local leakage position based on the vibration signal includes: Determining the short-time energy of each of the vibration sub-signals based on a short-time energy algorithm; When the short-time energy is greater than an energy threshold, it is determined that local leakage occurs at the vibration sensor position corresponding to the short-time energy, and the second local leakage position is determined based on the position of the vibration sensor.

9. The method for detecting partial leakage of electric power equipment according to claim 1, characterized in that: After obtaining the vibration signal of the power equipment collected by the grating array vibration sensing optical cable and the acoustic wave signal of the power equipment collected by the grating array acoustic wave sensing optical cable, the method further includes: The vibration signal and the sound wave signal are subjected to noise reduction processing respectively.

10. A local leakage detection device for electric power equipment, characterized in that: include: A signal acquisition unit, used to acquire a vibration signal of the power equipment collected by the grating array vibration sensing optical cable and an acoustic wave signal of the power equipment collected by the grating array acoustic wave sensing optical cable; an acoustic wave signal analysis unit, configured to construct an acoustic wave intensity probability distribution diagram based on the acoustic wave signal, and determine a target signal width based on the acoustic wave intensity probability distribution diagram; A first local leakage detection unit, configured to determine a first local leakage detection result based on the target signal width; a second local leakage detection unit, configured to perform wavelet packet decomposition on the vibration signal based on a preset wavelet basis to obtain a plurality of signal frequency bands, and determine a second local leakage detection result based on the plurality of signal frequency bands; The final local leakage detection unit is used to use the first local leakage detection result or the second local leakage detection result as the final local leakage detection result when the first local leakage detection result and the second local leakage detection result are the same.

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