CN115144707A - Partial discharge positioning method and device based on optical fiber sensing measurement ultrasonic signal - Google Patents
Partial discharge positioning method and device based on optical fiber sensing measurement ultrasonic signal Download PDFInfo
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- CN115144707A CN115144707A CN202210778183.4A CN202210778183A CN115144707A CN 115144707 A CN115144707 A CN 115144707A CN 202210778183 A CN202210778183 A CN 202210778183A CN 115144707 A CN115144707 A CN 115144707A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1209—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing using acoustic measurements
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- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
- G01H9/004—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means using fibre optic sensors
Abstract
The application discloses a partial discharge positioning method and device based on optical fiber sensing measurement ultrasonic signals. The scheme provided by the application is based on the ultrasonic signals obtained by the optical fiber sensing measurement system, the output signals of the optical fiber sensing measurement system, namely the amplitude of a Rayleigh backscattering spectrum curve group, are obtained through Hilbert transformation, the modulation information of the ultrasonic signals is obtained, the modulation effect on the disturbance signals is displayed through differential processing, the specific disturbance position is determined according to the time interval of the occurrence of the peak value in the signal curve group after the differential processing, the light velocity and the equivalent group velocity in the optical fiber and the pulse signal triggering time, and the local discharge positioning based on the optical fiber sensing measurement ultrasonic signals is realized.
Description
Technical Field
The application relates to the technical field of high voltage and insulation, in particular to a partial discharge positioning method and device based on optical fiber sensing measurement ultrasonic signals.
Background
In an electric power system, the operation state of various high-voltage electrical equipment directly determines the safety and stability of the whole system, and the partial discharge of a power cable is a main reason causing long-term deterioration of an insulation medium of the high-voltage electrical equipment, even breakdown, fire accident or permanent damage of the equipment. For a long time, the detection of partial discharges of power cables has been of great importance for the normal operation and fault prediction of high-voltage equipment. In recent years, with the rapid development of many new technologies in the industry, the phi-OTDR optical fiber sensing measurement is one of the technologies, and compared with the conventional measurement technology, the optical fiber sensing measurement technology has good insulation performance and is not easily subjected to electromagnetic interference, and has good application prospects in the field of partial discharge measurement.
At present, the optical fiber sensing measurement technology has been widely applied in the scenes of measuring strain, temperature, disturbance and the like, but the application of measuring the partial discharge ultrasonic signal of the power equipment is still under study, so how to further extract useful information from the measured ultrasonic signal to realize the partial discharge positioning based on the optical fiber sensing measurement ultrasonic signal becomes a technical problem that needs to be solved urgently by the technical personnel in the field.
Disclosure of Invention
The application provides a partial discharge positioning method and device based on an optical fiber sensing measurement ultrasonic signal, which are used for achieving the purpose of partial discharge positioning based on the optical fiber sensing measurement ultrasonic signal.
In order to achieve the above object, a first aspect of the present application provides a method for locating partial discharge based on optical fiber sensing measurement of ultrasonic signals, including:
acquiring an ultrasonic signal obtained through optical fiber sensing measurement;
carrying out waveform segmentation on the ultrasonic signals, and carrying out Hilbert transform on each waveform signal obtained by segmentation to obtain the amplitude of the waveform signal;
extracting an envelope curve of the ultrasonic signal based on the amplitude of each waveform signal to obtain a first curve group;
carrying out differential processing on the first curve group to obtain a differential curve group;
and determining a disturbance positioning interval based on the time interval of the peak value in the differential curve group by combining the light velocity in the optical fiber, the equivalent group velocity and the pulse signal triggering time.
Preferably, the determining a disturbance positioning interval based on the time interval in which the peak value appears in the differential curve group by combining the light velocity in the optical fiber, the equivalent group velocity, and the pulse signal trigger time specifically includes:
and based on the time interval of the peak value in the differential curve group, subtracting the pulse signal trigger time from the time interval, multiplying the time interval by the light velocity and the equivalent group velocity in the optical fiber, and determining the disturbance positioning interval according to half of the calculated product result.
Preferably, the method further comprises the following steps:
and determining the amplitude of the first curve group at the time point as a reference amplitude based on the time point of the peak value in the differential curve group, recombining the waveform signals based on the reference amplitude to obtain an externally disturbed vibration waveform signal, and performing FFT (fast Fourier transform) on the vibration waveform signal to obtain the main frequency of the vibration waveform signal so as to judge whether the ultrasonic signal is generated by partial discharge or not according to the main frequency.
Preferably, the waveform segmentation of the ultrasonic signal specifically includes:
according to the pulse signals in the trigger waveform of the optical fiber sensing measurement system, the ultrasonic signals are divided at equal intervals according to the trigger period of the pulse signals.
Preferably, before the performing the difference processing on the first curve group to obtain a difference curve group, the method further includes:
and carrying out white noise elimination processing on the first curve group to obtain a processed first curve group.
Meanwhile, the second aspect of the present application provides a partial discharge positioning apparatus for measuring an ultrasonic signal based on optical fiber sensing, including:
the signal acquisition unit is used for acquiring ultrasonic signals obtained through optical fiber sensing measurement;
the waveform segmentation unit is used for carrying out waveform segmentation on the ultrasonic signals and carrying out Hilbert transform on each waveform signal obtained by segmentation to obtain the amplitude of the waveform signal;
a first curve group extraction unit, configured to extract an envelope of the ultrasonic signal based on the amplitude of each waveform signal to obtain a first curve group;
the difference processing unit is used for carrying out difference processing on the first curve group to obtain a difference curve group;
and the positioning unit is used for determining a disturbance positioning interval based on the time interval of the peak value in the differential curve group by combining the light speed and the equivalent group velocity in the optical fiber and the pulse signal triggering time.
Preferably, the positioning unit is specifically configured to:
and based on the time interval of the peak value in the differential curve group, subtracting the pulse signal trigger time from the time interval, multiplying the time interval by the light velocity and the equivalent group velocity in the optical fiber, and determining the disturbance positioning interval according to half of the calculated product result.
Preferably, the method further comprises the following steps:
and the waveform master frequency extraction unit is used for determining the amplitude of the first curve group at the time point as a reference amplitude based on the time point of the peak value in the differential curve group, recombining the waveform signals based on the reference amplitude to obtain an externally disturbed vibration waveform signal, and performing FFT (fast Fourier transform) on the vibration waveform signal to obtain the master frequency of the vibration waveform signal so as to judge whether the ultrasonic signal is generated by partial discharge according to the master frequency.
Preferably, the waveform dividing unit is specifically configured to:
according to pulse signals in trigger waveforms of the optical fiber sensing measurement system, the ultrasonic signals are divided at equal intervals according to trigger periods of the pulse signals, and Hilbert transformation is carried out on each waveform signal obtained through division to obtain amplitude values of the waveform signals.
Preferably, the method further comprises the following steps:
and the white noise elimination unit is used for carrying out white noise elimination processing on the first curve group to obtain a processed first curve group.
According to the technical scheme, the embodiment of the application has the following advantages:
the method provided by the application is based on the ultrasonic signals obtained by the optical fiber sensing measurement system, the output signals of the optical fiber sensing measurement system, namely the amplitude of a Rayleigh backscattering spectrum curve group, are obtained through Hilbert transform, the envelope curve of the Rayleigh backscattering spectrum curve group is extracted, the modulation information of the ultrasonic signals is obtained, the modulation effect on disturbance signals is displayed through differential processing, the specific disturbance position is determined according to the time interval of the occurrence of the peak value in the signal curve group after the differential processing, the light velocity and the equivalent group velocity in the optical fiber and the pulse signal triggering time, and the local discharge positioning based on the optical fiber sensing measurement ultrasonic signals is realized.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.
Fig. 1 is a schematic flowchart of an embodiment of a partial discharge positioning method for measuring an ultrasonic signal based on optical fiber sensing according to the present application.
Fig. 2 is a schematic flowchart of another embodiment of a partial discharge positioning method for measuring an ultrasonic signal based on optical fiber sensing according to the present application.
FIG. 3 shows that the amplitude A of an ultrasonic signal s (t) is obtained by using Hilbert transform in a partial discharge positioning method for measuring the ultrasonic signal based on optical fiber sensing provided by the present application p (t) a calculation flowchart.
Fig. 4 is a time domain waveform diagram of a phi-OTDR ultrasonic signal in a single pulse period.
Fig. 5 is a waveform diagram of a differential curve group obtained by a local discharge positioning method for measuring an ultrasonic signal based on optical fiber sensing provided by the present application.
Figure 6 is a waveform diagram of an ultrasound signal reconstructed at a short axis time of 5.210 mus.
Figure 7 is an FFT spectrogram of an ultrasound signal reconstructed at a short axis time of 5.210 mus.
Fig. 8 is a schematic structural diagram of an embodiment of a partial discharge positioning apparatus for measuring an ultrasonic signal based on optical fiber sensing provided by the present application.
Detailed Description
The embodiment of the application provides a partial discharge positioning method and device based on an optical fiber sensing measurement ultrasonic signal, which are used for further extracting useful information from the ultrasonic signal obtained by measurement and achieving the purpose of partial discharge positioning based on the optical fiber sensing measurement ultrasonic signal.
In order to make the objects, features and advantages of the present invention more apparent and understandable, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the embodiments described below are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Referring to fig. 1, a partial discharge positioning method for measuring an ultrasonic signal based on optical fiber sensing according to a first embodiment of the present application includes:
And 102, carrying out waveform segmentation on the ultrasonic signals, and carrying out Hilbert transform on each waveform signal obtained by segmentation to obtain the amplitude of the waveform signal.
The ultrasonic signal obtained in step 101 is divided into N waveform signals by a waveform division processing method, and then the N waveform signals obtained by the division are subjected to hilbert transform, so that the amplitude of each waveform signal can be obtained after the transform.
And 103, extracting an envelope curve of the ultrasonic signal based on the amplitude of each waveform signal to obtain a first curve group.
Then, based on the amplitude of each waveform signal in the ultrasonic signal obtained through hilbert transform, an envelope curve of the ultrasonic signal is extracted in an envelope curve extraction manner, and the extracted envelope curve is the first curve group r mentioned in this embodiment i (i＝1,2,...,N)。
And 104, carrying out difference processing on the first curve group to obtain a difference curve group.
In the present embodiment, the difference processing is performed on the first curve group in order to show the relative change of the ultrasonic signal s (t) converted from the rayleigh backscattered light signal, and obtain the partial discharge ultrasonic modulation signal. The Rayleigh back scattering light of the optical fiber forms dynamic fluctuation after being modulated by an external vibration signal, because the vibration amplitudes at different moments are different, the modulation intensity of the scattering light is also different, and after the modulation process is sequentially carried out in a differential mode, the modulation process is shown. The specific method is to sequentially perform difference calculation on the first curve group to obtain a new difference curve group.
And 105, determining a disturbance positioning interval based on the time interval of the peak value in the differential curve group by combining the light speed in the optical fiber, the equivalent group velocity and the pulse signal triggering time.
Then, according to the differential curve group obtained in step 104, the time interval [ t ] of the short axis time axis where the peak of the differential curve group is located is determined 1 ,t 2 ]Then combining the optical speed in the optical fiber and the equivalent group velocity v g Determining a disturbance positioning interval [ z ] by the trigger time delta t of the pulse signal 1 ,z 2 ]Z in the perturbation localization interval 1 ,z 2 Refers to the length of the fiber from the entrance of the fiber, the distance of which is measured from the entrance of the fiber, and therefore, the disturbance location zone [ z ] 1 ,z 2 ]Can represent the source of the disturbing signal, i.e. the location of the partial discharge at a distance z from the entrance of the fibre 1 To z 2 Within the section (b).
The above is a detailed description of a first embodiment of the method for locating partial discharge based on optical fiber sensing measurement of ultrasonic signals provided by the present application, and the following is a detailed description of a second embodiment of the method for locating partial discharge based on optical fiber sensing measurement of ultrasonic signals provided by the present application.
Referring to fig. 2, based on the disclosure of the first embodiment, a partial discharge positioning method for measuring an ultrasonic signal based on optical fiber sensing according to a second embodiment of the present application includes:
further, in the step 102 mentioned in the first embodiment, the step process specifically includes:
according to the pulse signals in the trigger waveform of the optical fiber sensing measurement system, the ultrasonic signals are divided at equal intervals according to the trigger period of the pulse signals, and Hilbert transformation is carried out on each waveform signal obtained by division to obtain the amplitude of the waveform signal.
It should be noted that, in this embodiment, the trigger period of the pulse signal in the trigger waveform of the Φ -OTDR system is used as an equal interval to divide the detection signal waveform, so that each obtained waveform segment is a complete rayleigh backscatter spectrum curve of each trigger signal on the optical fiber segment. Then, the amplitude of the output signal of the phi-OTDR system, i.e. the rayleigh backscattering spectrum curve, is solved by using hilbert transform and the envelope curve is extracted, in order to obtain the modulation information of the partial discharge ultrasonic signal loaded on the rayleigh backscattering spectrum curve, the specific principle is as follows:
the phi-OTDR system converts Rayleigh back scattering optical signals into electric signals through a photoelectric detector and outputs the electric signals, and the voltage signal expression of the phi-OTDR system is as follows:
wherein G is the voltage gain in V/A;
is the photoelectric conversion coefficient of the photodiode, with the unit being A/W;
and
respectively the power of the Rayleigh back scattering light and the local oscillator reference light; omega IF ＝ω c -ω LO ＝2πΔf IF Is the difference frequency of the signal light and the reference light, where Δ f IF I.e. the intermediate frequency; phi is a s ,φ LO Is the phase of the rayleigh backscattered light and the local oscillator reference light.
Phase shift function phi introduced by ultrasonic disturbance p (t L ) Simultaneously changing the output signal s (t) of a phi-OTDR system by the modulation of amplitude and phase, writing an expression of the output signal s (t) into a packetContaining an amplitude modulation term A p (t) and a phase modulation term phi p Form (t):
s(t)＝A p (t)cos[ω IF t+φ IF +φ p (t)]
in the formula, phi IF ＝φ s -φ LO Representing the phase difference in the absence of ultrasonic perturbations; amplitude modulation term
Is a modulation function in the presence of external ultrasonic disturbances which is implicitly related to the ultrasonic signal; new phase modulation term phi p (t) the corresponding ultrasound phase offset function sampled with equal period pulses can be written as:
in the formula, t L ＝t+nT p Is the major axis time (the time of perturbation of the ultrasonic wave to the fiber) t L And the minor axis time (transit time of a single pulse of light in the fiber from the entrance of the fiber) t; t is p Is the sampling period of the ultrasound; n =1,2 L For T p Integer quotient of modulo operation representing sequence signal s (n) The sequence number of (t), i.e., the sequence number of the sampling point for ultrasonic disturbance.
The detection signal s (t) of each pulse light is rewritten according to the sampling number n as follows:
where the amplitude modulation term
And phase modulation term
It becomes the dominant form associated with the sequence of discrete samples n of the ultrasound signal.
Detecting a sequence signal s from a detected sequence signal using Hilbert Transform (HT) digital signal processing (n) (t) analyzing the amplitude modulation term
And phase modulation term
I.e. signal demodulation.
Due to phi-OTDR system detecting signal s (n) (t) the phase modulation signal has random waveform characteristics and is corresponding to local discharge ultrasonic disturbance
To only s (n) (t) a certain part of the signal (t = t) 0 Nearby) acts as a modulation, causing s (n) (t) at t = t 0 Phase shifts of different magnitudes occur nearby. Thus, for s (n) (t) ultrasonic phase modulation signals whose incremental transformation of the signal helps to find local effects
The transformation is done as follows:
s (n) (t)＝s 0 (t)-Δs (n) (t)
in the formula, s 0 (t) represents the output signal of the phi-OTDR system at a certain initial instant without or with ultrasonic disturbance, deltas (n) (t) represents the following t L ＝t+nT p S obtained at a time (n) (t) signal vs. s 0 (t) an incremental signal; phi in the general formula IF Is decomposed into phi 0 +φ n In which phi 0 Is t = t 0 Time and ultrasonic disturbance independent phase delay of self propagation of Rayleigh back scattering light phi n Is the phase noise introduced by the laser.
Δs (n) (t) the incremental signal is still ω IF Frequency band modulated signals comprising
And
more complex forms of modulation, but further modulating the ultrasound phase function
The amplitude modulation term is advantageous for demodulating the partial discharge ultrasonic signal through the amplitude detection of the signal. Since the ultrasonic frequency band of the partial discharge signal is in the range of 20kHz to 200kHz,
and
are all relative to the intermediate frequency ω IF The bandwidth of the narrow-band function of the frequency band is set to be delta v, and the delta v is far smaller than the intermediate frequency omega IF And/2 pi. Thus, at Δ s (n) Sin (ω) in (t) signals IF t) in the sine wave oscillation waveform,
and
the speed of change with time is slow and when the defined conditions are met: Δ t < 1/Δ v, it can be considered that these two functions are approximately constant over the Δ t period. Therefore,. DELTA.s (n) (t) the incremental signal is approximated as a time t (angular frequency ω) IF ) Only its amplitude and phase are slowly modulated.
First, Δ s is calculated using the Hilbert transform (n) (t) the quadrature signal for the incremental signal, as shown in the following equation:
in the formula
And Δ s (n) The difference in the expression (t) is with respect to the intermediate frequency ω IF The oscillation function of (2) changes from a sine signal to a cosine signal, and the two signals are orthogonal signals.
Then by Δ s (n) (t) is a real part and
complex analytic signal forms can be constructed for the imaginary part:
complex number analytic signal z (n) The modulus and phase angle of (t) can be given by:
wherein the content of the first and second substances,
as can be seen, | z (n) (t) | is independent of the intermediate frequency angular frequency ω IF But χ (t) depends on a particular ω IF 。
Finally, the incremental signal deltas (n) The amplitude modulation term and the phase modulation term of (t) are abbreviated as A (n) (t) and Φ (n) (t), it is possible to obtain:
A (n) (t)＝2|z (n) (t)|
Φ (n) (t)＝χ(t)-(ω IF t+φ 0 )
in order to facilitate the processing and analysis of data, the demodulation algorithm provided by the invention firstly utilizes the Hilbert transform to obtain the amplitude corresponding to the detection signal, and then differential processing is carried out on the amplitude to obtain the modulation signal, and the measure is consistent with the incremental transform effect.
The envelope extracted by using Hilbert transform is named as a curve group r i (i =1, 2.., N), where N represents the number of segments segmented in step 102. The amplitude A corresponding to the detection signal s (t) is obtained by using Hilbert transform p The calculation flow of (t) is shown in FIG. 3.
Further, after obtaining the first curve group in step 103, and before performing the difference processing on the first curve group in step 104 to obtain the difference curve group, the method may further include:
and step 1031, performing white noise elimination processing on the first curve group to obtain a processed first curve group.
It should be noted that, this step is to eliminate power noise and phase noise of the laser in the Φ -OTDR system, and the processing mode may be moving average processing, so as to obtain the first curve group R after smoothing processing i (i =1, 2.. Said., M), where M is related to the value of the selected running average step size k, i.e. M = N/k. Then, when step 104 is executed, the first curve group R after the smoothing process can be used i (i =1, 2.., M) is differentially processed, i.e., Δ R i ＝R i -R 1 。
Further, in step 105 according to the first embodiment, the step process specifically includes:
based on the time interval of the peak value in the differential curve group, subtracting the pulse signal trigger time from the time interval, multiplying the time interval by the light velocity and the equivalent group velocity in the optical fiber, and determining the disturbance positioning interval according to half of the calculated product result.
It should be noted that, from the difference curve group obtained in step 105, a time interval [ t ] on the short-axis time axis where the peak of the difference curve group is located is determined 1 ,t 2 ]The actual trigger time delta t is subtracted from the time interval and then multiplied by the speed of light in the optical fiber and the equivalent group velocity v g And dividing by 2 to obtain the actual disturbance positioning interval [ z 1 ,z 2 ]。
Further, obtaining the differential curve set in step 104 may further include:
It should be noted that this step is performed by selecting the peak time point at r i The amplitude on the original waveform can be recombined to obtain a waveform array of N elements, and the extracted new array is named as p (t) i ) T in this waveform array i Is exactly the repetition period of the detection light pulse. The new waveform array is a vibration waveform of the external disturbance, the waveform is subjected to FFT to obtain the main frequency of the waveform, and whether the external disturbance is an ultrasonic signal generated by partial discharge can be judged according to the frequency.
In addition, the execution sequence of step 1041 mentioned in this embodiment may be arranged after step 104, and this step may be executed synchronously with step 105, or before or after step 105.
To further explain the technical solution of the present application, this embodiment further provides a test example of performing measurement and demodulation in a Φ -OTDR optical fiber sensing system based on the method provided by the present application, which specifically includes:
by using the method provided by the application, the simulated frequency f in the phi-OTDR optical fiber sensing system p Ultrasonic signal of =20kHzMeasurements and demodulation were performed. The triggering period of the detection pulse optical signal is 10 mus, the sampling rate of the acquisition system is 1GS/s, the duration of the acquisition waveform is 2ms, the length of the optical fiber is 758m, and the time required for the optical signal to go back and forth in the test optical fiber is 7.58 mus. The waveform of the detection signal obtained by the waveform division in step 102 is a waveform of a detection signal of a certain division section, as shown in fig. 4, a violent oscillation part of the waveform corresponds to RBS scattered light signals on the test optical fiber, the length of the waveform is 7.58 mus, which is a basic waveform of the phi-OTDR sensing detection, that is, the detection waveform is considered to be stable when the optical fiber is not subjected to any external disturbance, that is, the detection waveform can represent a "background fingerprint" specific to the detected optical fiber itself.
The set of difference curves obtained by the method provided by the present application is shown in fig. 5. It can be seen from the figure that the differential curve group shows a relatively obvious peak in the minor axis time interval [5.19 μ s,5.22 μ s ], the total length of the test fiber is 758m as in the previous embodiment, wherein the sensing fiber segment wound around the piezoelectric actuator, i.e. the disturbance source, is located in the [491m,495m ] interval, the trigger time of the trigger pulse is 0.264 μ s in the experiment, the difference curve fluctuation time interval minus the trigger time results in the locating interval [492.6m,495.6m ], and the maximum deviation of the actually set sensing fiber segment position is 0.6m.
The waveform reconstruction is carried out by taking the short-axis time of 5.210 mu s as a peak time point, the amplitude of ri original waveform on 5.210 mu s is selected, and a waveform array of 200 elements is obtained through reconstruction, the waveform acquisition time of the embodiment of the invention is 2ms, so that the ultrasonic signal obtained through reconstruction is also a section of waveform with the time of 2ms, and the time domain waveform is shown in fig. 6. It should be noted that the algorithm of the present invention is suitable for demodulating the waveform appearance of the disturbance signal in the time domain, and cannot really represent the original ultrasonic signal.
The FFT spectrum of the reconstructed waveform is as shown in fig. 7, and the 20kHz single-frequency ultrasonic signal set in the experiment can be clearly seen from the spectrogram, which shows that the method can effectively obtain the main frequency of the disturbance signal. In the engineering application of actual measurement of partial discharge, whether the disturbance signal is generated by partial discharge can be judged according to the main frequency of the FFT frequency spectrum of the measured disturbance signal.
The above is a detailed description of a partial discharge localization method based on optical fiber sensing measurement of ultrasonic signals according to a second embodiment of the present application, and the following is a detailed description of an embodiment of a partial discharge localization apparatus based on optical fiber sensing measurement of ultrasonic signals according to the present application.
Referring to fig. 8, a third embodiment of the present application provides a partial discharge positioning apparatus for measuring an ultrasonic signal based on optical fiber sensing, including:
a signal acquisition unit 201 for acquiring an ultrasonic signal obtained by optical fiber sensing measurement;
a waveform division unit 202 that performs waveform division on the ultrasonic signal, and performs hilbert transform on each waveform signal obtained by the division to obtain an amplitude of the waveform signal;
a first curve group extraction unit 203, configured to extract an envelope curve of the ultrasonic signal based on the amplitude of each waveform signal, so as to obtain a first curve group;
a difference processing unit 204, configured to perform difference processing on the first curve group to obtain a difference curve group;
and the positioning unit 205 is configured to determine a disturbance positioning interval based on a time interval in which a peak value in the differential curve group occurs, in combination with the light velocity in the optical fiber, the equivalent group velocity, and the pulse signal trigger time.
Further, the positioning unit 205 is specifically configured to:
based on the time interval of the peak value in the differential curve group, subtracting the pulse signal trigger time from the time interval, multiplying the time interval by the light velocity and the equivalent group velocity in the optical fiber, and determining the disturbance positioning interval according to half of the calculated product result.
Further, still include:
the waveform master frequency extracting unit 2041 is configured to determine an amplitude of the first curve group at a time point based on the time point at which the peak occurs in the differential curve group as a reference amplitude, recombine each waveform signal based on the reference amplitude to obtain an externally disturbed vibration waveform signal, and perform FFT on the vibration waveform signal to obtain a master frequency of the vibration waveform signal, so as to determine whether the ultrasonic signal is generated by partial discharge according to the master frequency.
Further, the waveform dividing unit 202 is specifically configured to:
according to the pulse signals in the trigger waveform of the optical fiber sensing measurement system, the ultrasonic signals are divided at equal intervals according to the trigger period of the pulse signals, and Hilbert transformation is carried out on each waveform signal obtained by division to obtain the amplitude of the waveform signal.
Further, still include:
a white noise elimination unit 2031 configured to perform white noise elimination processing on the first curve group to obtain a processed first curve group.
It can be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working processes of the terminal, the apparatus and the unit described above may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In the several embodiments provided in the present application, it should be understood that the disclosed terminal, apparatus and method may be implemented in other manners. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The terms "first," "second," "third," "fourth," and the like in the description of the application and the above-described figures, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit may be implemented in the form of hardware, or may also be implemented in the form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk, and various media capable of storing program codes.
The above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.
Claims (10)
1. A partial discharge positioning method based on optical fiber sensing measurement ultrasonic signals is characterized by comprising the following steps:
acquiring an ultrasonic signal obtained through optical fiber sensing measurement;
carrying out waveform segmentation on the ultrasonic signals, and carrying out Hilbert transform on each waveform signal obtained by segmentation to obtain the amplitude of each waveform signal;
extracting an envelope curve of the ultrasonic signal based on the amplitude of each waveform signal to obtain a first curve group;
carrying out differential processing on the first curve group to obtain a differential curve group;
and determining a disturbance positioning interval based on the time interval of the peak value in the differential curve group by combining the light velocity in the optical fiber, the equivalent group velocity and the pulse signal triggering time.
2. The method according to claim 1, wherein the determining a disturbance location interval based on the time interval in which the peak occurs in the differential curve group by combining the light velocity and the equivalent group velocity in the optical fiber and the pulse signal trigger time specifically comprises:
and based on the time interval of the peak value in the differential curve group, subtracting the pulse signal trigger time from the time interval, multiplying the time interval by the light velocity in the optical fiber and the equivalent group velocity, and determining the disturbance positioning interval according to half of the calculated product result.
3. The method for locating partial discharge based on the optical fiber sensing measurement ultrasonic signal according to claim 1, further comprising:
and determining the amplitude of the first curve group at the time point as a reference amplitude based on the time point of the peak value in the differential curve group, recombining the waveform signals based on the reference amplitude to obtain an externally disturbed vibration waveform signal, and performing FFT (fast Fourier transform) on the vibration waveform signal to obtain the main frequency of the vibration waveform signal so as to judge whether the ultrasonic signal is generated by partial discharge or not according to the main frequency.
4. The method according to claim 1, wherein the waveform segmentation of the ultrasonic signal specifically comprises:
according to the pulse signals in the trigger waveform of the optical fiber sensing measurement system, the ultrasonic signals are divided at equal intervals according to the trigger period of the pulse signals.
5. The method according to claim 1, wherein the step of performing the differential processing on the first curve group to obtain a differential curve group further comprises:
and carrying out white noise elimination processing on the first curve group to obtain a processed first curve group.
6. A partial discharge positioning device based on optical fiber sensing measurement ultrasonic signals is characterized by comprising:
the signal acquisition unit is used for acquiring ultrasonic signals obtained through optical fiber sensing measurement;
the waveform segmentation unit is used for carrying out waveform segmentation on the ultrasonic signals and carrying out Hilbert transform on each waveform signal obtained by segmentation to obtain the amplitude of each waveform signal;
a first curve group extraction unit, configured to extract an envelope of the ultrasonic signal based on the amplitude of each waveform signal to obtain a first curve group;
the difference processing unit is used for carrying out difference processing on the first curve group to obtain a difference curve group;
and the positioning unit is used for determining a disturbance positioning interval by combining the light speed in the optical fiber, the equivalent group velocity and the pulse signal triggering time based on the time interval of the peak value in the differential curve group.
7. The partial discharge positioning apparatus for measuring ultrasonic signals based on optical fiber sensing according to claim 6, wherein the positioning unit is specifically configured to:
and based on the time interval of the peak value in the differential curve group, subtracting the pulse signal trigger time from the time interval, multiplying the time interval by the light velocity in the optical fiber and the equivalent group velocity, and determining the disturbance positioning interval according to half of the calculated product result.
8. The device for locating partial discharge based on fiber-optic sensing measurement ultrasonic signals according to claim 6, further comprising:
and the waveform master frequency extraction unit is used for determining the amplitude of the first curve group at the time point as a reference amplitude based on the time point of the peak value in the differential curve group, recombining the waveform signals based on the reference amplitude to obtain an externally disturbed vibration waveform signal, and performing FFT (fast Fourier transform) on the vibration waveform signal to obtain the master frequency of the vibration waveform signal so as to judge whether the ultrasonic signal is generated by partial discharge according to the master frequency.
9. The device according to claim 6, wherein the waveform segmentation unit is specifically configured to:
according to pulse signals in trigger waveforms of the optical fiber sensing measurement system, the ultrasonic signals are divided at equal intervals according to trigger periods of the pulse signals, and Hilbert transformation is carried out on each waveform signal obtained through division to obtain amplitude values of the waveform signals.
10. The device for locating partial discharge based on fiber-optic sensing measurement ultrasonic signals according to claim 6, further comprising:
and the white noise elimination unit is used for carrying out white noise elimination processing on the first curve group to obtain a processed first curve group.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116754910A (en) * | 2023-08-14 | 2023-09-15 | 广东电网有限责任公司珠海供电局 | Cable partial discharge monitoring method, system and equipment based on multipath optical fiber difference |
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| CN116754910A (en) * | 2023-08-14 | 2023-09-15 | 广东电网有限责任公司珠海供电局 | Cable partial discharge monitoring method, system and equipment based on multipath optical fiber difference |
| CN116754910B (en) * | 2023-08-14 | 2024-01-09 | 广东电网有限责任公司珠海供电局 | Cable partial discharge monitoring method, system and equipment based on multipath optical fiber difference |
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