CN114371365B - Cable defect positioning method, device and storage medium - Google Patents
Cable defect positioning method, device and storage medium Download PDFInfo
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- CN114371365B CN114371365B CN202210030652.4A CN202210030652A CN114371365B CN 114371365 B CN114371365 B CN 114371365B CN 202210030652 A CN202210030652 A CN 202210030652A CN 114371365 B CN114371365 B CN 114371365B
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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
- G01R31/08—Locating faults in cables, transmission lines, or networks
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
- Y04S10/52—Outage or fault management, e.g. fault detection or location
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Abstract
The invention discloses a cable defect positioning method, equipment and a storage medium, which are used for solving the technical problem that the existing cable defect positioning method cannot accurately position cable defects. The method of the invention comprises the following steps: the signal generator inputs a first preset detection signal from the head end of the cable to be detected, and the signal collector collects a detection return signal of the first preset detection signal at the head end of the cable to be detected; performing Hilbert transform on the detection return signal to obtain a transformed signal, and determining a complex signal to be analyzed based on the transformed signal and the detection return signal; the complex signal to be analyzed is used for analyzing the defect position of the cable to be tested; and performing correlation comparison on the complex signal to be analyzed and a second preset detection signal to determine the defect position of the cable to be tested. The invention solves the technical problem that the existing cable defect positioning method cannot accurately position the cable defect.
Description
Technical Field
The present invention relates to the field of cable fault locating technologies, and in particular, to a method, an apparatus, and a storage medium for locating cable defects.
Background
The quality of the electric energy becomes a key factor for improving the working stability and benefit of various industries. The integrity of the tool that transmits the electrical energy directly affects the stability of the power supply, and maintenance must also be performed periodically. The cable has become a necessary electric energy transmission tool for urban electricity because of the advantages of good transmission performance, small occupied area and the like. However, the cable may have a certain minor defect due to factors such as process errors in the manufacturing process, and the cable may be locally aged if the cable is operated for too long under a humid or high-temperature unfavorable environment, so that insulation of the cable is deteriorated, and if the cable cannot be replaced in time, a power failure accident of the whole circuit may be caused, thereby causing huge economic loss to the power industry and users.
Based on the above problems, the utility company periodically dispatches related maintenance workers to remove cable faults, and conventional methods include an oscillatory wave partial discharge detection method, a time domain reflection method, a frequency domain reflection method and the like. However, the oscillating wave partial discharge detection method is easy to be interfered by noise, the time domain reflection method cannot detect weak defects, and the frequency domain reflection method causes excessive misjudgment factors, so that the cable defects cannot be accurately positioned.
Disclosure of Invention
The invention provides a cable defect positioning method, equipment and a storage medium, which are used for solving the technical problem that the existing cable defect positioning method cannot accurately position a cable defect.
In a first aspect, the present invention provides a method for locating a cable defect, the method comprising: the signal generator inputs a first preset detection signal from the head end of the cable to be detected, and the signal collector collects a detection return signal of the first preset detection signal at the head end of the cable to be detected; the head end of the cable to be tested is a detection end for detecting the cable to be tested; performing Hilbert transform on the detection return signal to obtain a transformed signal, and determining a complex signal to be analyzed based on the transformed signal and the detection return signal; the complex signal to be analyzed is used for analyzing the defect position of the cable to be tested; carrying out correlation comparison on the complex signals to be analyzed and a second preset detection signal to determine the defect position of the cable to be tested; wherein the first preset detection signal is the real part of the second preset detection signal; the second predetermined probing signal is a standard complex probing signal comprising a real part and an imaginary part.
According to the cable defect positioning method provided by the invention, a first preset detection signal is input from the head end of the cable to be detected through the signal generator, and the signal collector collects a detection return signal at the head end of the cable to be detected; then, hilbert transformation is carried out on the detection return signal, so that a complex signal to be analyzed containing a real part and an imaginary part is obtained based on the change signal and the detection return signal; and then carrying out analysis correlation analysis on the second detection signal serving as the standard complex detection signal and the complex signal to be analyzed, thereby obtaining the defect position of the cable to be detected. The method effectively solves the technical problem that the existing cable defect positioning method cannot accurately position the cable defect.
In one implementation of the present invention, the first preset probing signal is determined by the following formula:
wherein s is R (t) is a first preset detection signal, t is the output time of the first preset detection signal, alpha is a first constant, t 0 For the central time of the duration of the first preset detection signal in the cable, beta is a second constant, omega 0 Is the angular frequency center of the first preset detection signal.
In one implementation of the present invention, before the signal generator inputs the first preset detection signal from the head end of the cable to be tested, the method further includes:
calculating the central time t of the duration of the first preset detection signal in the cable to be tested based on the preset normalized Gaussian envelope signal 0 The method comprises the steps of carrying out a first treatment on the surface of the And calculating the angular frequency center omega of the first preset detection signal based on the first constant and the second constant 0 。
In one implementation of the invention, the complex signal to be analyzed is represented by the following formula:
z(t)＝s r (t)+jH[s r (t)]
wherein z (t) is the complex signal to be analyzed, s r (t) is the detection return signal, hs r (t)]To transform the signal.
In one implementation of the present invention, performing hilbert transformation on a probe return signal to obtain a transformed signal, and determining a complex signal to be analyzed based on the transformed signal and the probe return signal, specifically includes: rotating the probe return signal by 90 ° clockwise in the frequency domain based on the hilbert transform, thereby obtaining a transformed signal; the detection return signal is taken as a real part forming the complex signal to be analyzed, and the conversion signal is taken as an imaginary part forming the complex signal to be analyzed, so that the complex signal to be analyzed is obtained.
In one implementation of the present invention, before the correlation comparison of the complex signal to be analyzed with the second preset detection signal, the method further includes: determining the time-frequency distribution of the complex signal to be analyzed based on the wiener distribution function; and determining the time-frequency distribution of the second preset detection signal based on the wiener distribution function.
In one implementation manner of the present invention, the correlation comparison between the complex signal to be analyzed and the second preset detection signal is performed to determine the defect position of the cable to be tested, which specifically includes: based on a preset correlation function, determining the correlation distribution of the time-frequency distribution of the complex signal to be analyzed and the time-frequency distribution of a second preset detection signal in the time domain; the correlation function is a function taking time as a variable, and the correlation distribution is used for carrying out correlation analysis on the complex signal to be analyzed and a second preset detection signal; determining a plurality of maxima in the correlation distribution, and determining whether the plurality of maxima are greater than a preset defect amplitude threshold; determining time parameters of abscissa corresponding to maximum values larger than a preset threshold value in a plurality of maximum values; and determining the distance from the defect position to the head end of the cable to be tested based on the time parameter of the abscissa.
In one implementation of the present invention, determining a distance from a defect position to a head end of a cable to be tested based on a time parameter of an abscissa specifically includes: among a plurality of maximum values larger than a preset threshold value, determining that the position corresponding to the first maximum value is the head end of the cable to be tested, determining that the position corresponding to the last maximum value is the tail end of the cable to be tested, and determining that the positions corresponding to the maximum values between the first maximum value and the last maximum value are defect positions; based on the performance parameters of the cable to be tested, determining the transmission speed of a first preset detection signal in the cable to be tested, and based on the transmission speed and the time parameters of the abscissa corresponding to the defect position, determining the specific distance from the defect position to the head end of the cable to be tested.
In a second aspect, the present invention also provides a cable fault locating device, the device comprising: a processor; and a memory having executable code stored thereon that, when executed, causes the processor to perform any of the cable fault locating methods described above.
In a third aspect, the present invention also provides a non-volatile computer storage medium for cable fault localization, storing computer executable instructions, the computer executable instructions being configured to: the signal generator inputs a first preset detection signal from the head end of the cable to be detected, and the signal collector collects a detection return signal of the first preset detection signal at the head end of the cable to be detected; the head end of the cable to be tested is a detection end for detecting the cable to be tested; performing Hilbert transform on the detection return signal to obtain a transformed signal, and determining a complex signal to be analyzed based on the transformed signal and the detection return signal; the complex signal to be analyzed is used for analyzing the defect position of the cable to be tested; carrying out correlation comparison on the complex signals to be analyzed and a second preset detection signal to determine the defect position of the cable to be tested; wherein the first preset detection signal is the real part of the second preset detection signal; the second predetermined probing signal is a standard complex probing signal comprising a real part and an imaginary part.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and do not constitute a limitation on the invention. In the drawings:
FIG. 1 is a flow chart of a method for locating cable defects according to an embodiment of the present invention;
fig. 2 is a schematic diagram of an internal structure of a cable defect positioning device according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments of the present invention and corresponding drawings. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
When the time-frequency domain reflection method is used for positioning the defects of the cable to be tested, a complex type detection signal is required to be incident to the cable to be tested, so that a time domain signal returned after the detection signal is reflected in the cable to be tested can be converted into a time-frequency domain. However, the existing signal generator device cannot generate the imaginary part of the detection signal, and cannot form a complex signal, so that the collected time domain signal cannot be converted into a time domain for analysis, and therefore, the position of the cable defect to be detected cannot be accurately positioned.
The embodiment of the invention provides a cable defect positioning method, equipment and a storage medium, which are used for solving the technical problem that the existing cable defect positioning method cannot accurately position cable defects.
The following describes the technical scheme provided by the embodiment of the invention in detail through the attached drawings.
Fig. 1 is a flowchart of a cable defect positioning method according to an embodiment of the present invention. As shown in fig. 1, the testing method provided by the embodiment of the invention mainly includes the following steps:
step 101, while the signal generator inputs a first preset detection signal from the head end of the cable to be detected, the signal collector collects a detection return signal of the first preset detection signal at the head end of the cable to be detected.
In one embodiment of the present invention, the present invention provides a first preset detection signal input to a head end of a cable to be tested by a signal generator in order to locate a cable defect. It should be noted that the head end of the cable to be tested is the detection end for detecting the cable to be tested. The first preset detection signal is determined by the following formula:
wherein s is R (t) is a first preset detection signal, t is the output time of the first preset detection signal, alpha is a first constant, t 0 For the central time of the duration of the first preset detection signal in the cable to be detected, beta is a second constant, omega 0 Is the angular frequency center of the first preset detection signal. The first constant is a parameter affecting the duration of the signal and the frequency range of the signal, and the second constant is a parameter affecting the frequency range of the signal.
In the embodiment of the present invention, α is optionally 2.21×1016, and β is 1.22×1016.
It can be understood that the first preset detection signal is a time domain signal and is a real signal, and the defect position of the cable to be tested is measured through the first preset detection signal.
Due to t in the first preset detection signal 0 (i.e. the central time of the duration of the first preset detection signal in the cable) and ω 0 (i.e. the angular frequency center of the first preset detection signal) is embodied in the form of a parameter in the first preset detection signal, so that the central time t of the duration of the first preset detection signal in the cable is calculated based on the preset normalized gaussian envelope signal before the signal generator inputs the first preset detection signal from the head end of the cable to be tested 0 The method comprises the steps of carrying out a first treatment on the surface of the And calculating the angular frequency center omega of the first preset detection signal based on the cable length and the performance parameters of the cable 0 。
Specifically, since the first constant is first input into a preset normalized gaussian envelope signal to determine a positive boundary coefficient a with an envelope magnitude smaller than a preset threshold, where the positive boundary coefficient a is a time of a positive half axis corresponding to an envelope extremum with the first envelope magnitude smaller than the preset threshold, the normalized gaussian envelope signal is represented by the following formula:
wherein g (t) is a normalized Gaussian envelope signal, t is a time parameter, and alpha is a first constant.
Bringing the determined positive boundary coefficient A into the following formula to determine the central time t of the duration of the first preset detection signal in the cable 0 ：
Where A is a positive boundary coefficient and α is a first constant.
Angular frequency center omega of first preset detection signal 0 Is determined by the following formula:
where α is a first constant and β is a second constant.
In one embodiment of the invention, after determining the first preset probing signal, the first preset probing signal is generated in the signal generator and then is input into the cable under test from the head end of the cable under test. And the signal collector should collect the detection return signal returned based on the first preset detection signal at the head end of the cable to be detected. It will be appreciated that after a signal is input to the cable under test, there will be reflections of the signal which will behave differently in different positions of the cable, so that the cable under test can be analysed based on the probe return signal.
Step 102, hilbert transformation is performed on the detection return signal to obtain a transformation signal, and a complex signal to be analyzed is determined based on the transformation signal and the detection return signal.
In one embodiment of the invention, after acquisition of the probe return signal is completed, the probe return signal is subjected to a Hilbert transform to obtain a transformed signal.
Specifically, the probe return signal is brought into the hilbert transform formula:
wherein s is r (t) is the probe return signal and τ is the time variable for integration.
In the case of fourier transform of the detection return signal subjected to the hilbert transform, it can be seen that the hilbert transform performs 90 ° phase shift processing on the original real signal (i.e., the detection return signal) in the frequency domain. The specific transformation is as follows:
where F is the Fourier transform and sgn (ω) is the sign function.
It will be appreciated that the Hilbert transform is rotated 90 deg. clockwise for the positive frequency portion, zeroed for the original signal frequency response at frequency 0, and rotated 90 deg. counter-clockwise for the negative frequency portion. However, for the real signal in the embodiment of the present invention, since the frequency ranges selected by the parameters are all positive, the hilbert transform is to rotate the frequency domain of the real signal by 90 ° clockwise, so that the transformed signal obtained by the hilbert transform can be used as the imaginary part of the complex signal to be analyzed.
In one embodiment of the invention, after determining the transformed signal corresponding to the probe return signal, the complex signal to be analyzed is determined based on the transformed signal and the probe return signal. It is understood that the complex signal to be analyzed is used to analyze the defective location of the cable under test.
Specifically, the complex signal to be analyzed is represented by the following formula:
z(t)＝s r (t)+jH[s r (t)]
wherein z (t) is the complex signal to be analyzed, s r (t) is the detection return signal, hs r (t)]To transform the signal.
And 103, performing correlation comparison on the time-frequency distribution of the complex signal to be analyzed and the time-frequency distribution of the second preset detection signal to determine the defect position of the cable to be tested.
In one embodiment of the present invention, after determining the complex signal to be analyzed, the complex signal to be analyzed and the second preset detection signal are first processed through a wiener distribution function to determine a time-frequency distribution of the complex signal to be analyzed and determine a time-frequency distribution of the second preset detection signal.
It should be noted that, the second preset detection signal is a standard complex detection signal including a real part and an imaginary part, that is, a signal that should be input from the head end of the cable to be tested for defect positioning, so it can be understood that the first preset detection signal is a real part of the second preset detection signal.
Specifically, the complex signal to be analyzed and the second preset detection signal are brought into the following formula:
wherein W (t, ω) is the Wigner distribution function, t is time, ω is angular frequency, τ is the autocorrelation time variable,is a complex conjugate function after the independent variable substitution of the analytic signal z (t) after Hilbert transformation,/and%>Is a two-dimensional signal after the independent variable substitution of the analysis signal z (t) after Hilbert transformation.
In one embodiment of the present invention, after determining the time-frequency distribution of the complex signal to be analyzed and determining the time-frequency distribution of the second preset detection signal based on the wiener distribution function, the time-frequency distribution of the complex signal to be analyzed is compared with the time-frequency distribution of the second preset detection signal in a correlation manner.
Specifically, firstly, determining the correlation distribution of a complex signal to be analyzed and a second preset detection signal in a time domain based on a preset correlation function; the correlation function is a function taking time as a variable, and the correlation distribution is used for carrying out correlation analysis on the complex signal to be analyzed and the second preset detection signal. A correlation function, represented by the following formula:
wherein C (T) is a correlation function of the time variable T, T' is an integrated time variable, T s Half the duration of the second predetermined probing signal; omega is the instantaneous angular frequency of the signal; w (W) r The time-frequency distribution of the complex signals to be analyzed; w (W) s The time-frequency distribution of the second preset detection signal is obtained; e (E) s A normalization factor E for the time-frequency distribution of the second preset detection signal r And (t) is a normalization function of the time-frequency distribution of the complex signal to be analyzed.
In one embodiment of the invention, after determining the correlation distribution of the complex signal to be analyzed and the second preset detection signal in the time domain, a number of maxima in the correlation distribution are determined. And then determining whether each maximum value is larger than a preset threshold value according to the preset defect amplitude threshold value. After determining the maximum value larger than the defect amplitude threshold value in the plurality of maximum values, determining the time parameter of the abscissa corresponding to the maximum value larger than the preset threshold value in the plurality of maximum values. And determining the distance from the defect position to the head end of the cable to be tested based on the time parameter of the abscissa.
It can be understood that, because the head end of the cable to be tested and the tail end of the cable to be tested are discontinuous, the maximum values of the head end of the cable to be tested and the tail end of the cable to be tested are necessarily larger than the preset defect amplitude threshold, therefore, among a plurality of maximum values larger than the preset threshold, the position corresponding to the first maximum value is determined to be the head end of the cable, the position corresponding to the last maximum value is determined to be the tail end of the cable, and the positions corresponding to the maximum values between the first maximum value and the last maximum value are determined to be defect positions.
In one embodiment of the invention, after determining the position of the cable defect in the correlation distribution, firstly, determining the transmission speed of the signal in the cable based on the performance parameter of the cable, and then determining the specific distance from the defect position to the head end of the cable based on the transmission speed and the time parameter of the abscissa in the correlation distribution corresponding to the defect position.
Specifically, the time parameter of the abscissa corresponding to the transmission speed and the defect position is brought into the following formula:
wherein x is the distance from the defect position to the head end of the cable, v is the transmission speed of the signal on the cable, and t is the time parameter of the abscissa in the correlation distribution corresponding to the defect position.
The method embodiment provided by the invention is based on the same inventive concept, and the invention also provides a cable defect positioning device, the internal structure of which is shown in fig. 2.
Fig. 2 is a schematic diagram of an internal structure of a cable defect positioning device according to an embodiment of the present invention. As shown in fig. 2, the apparatus includes: a processor 201; the memory 202 has stored thereon executable instructions that, when executed, cause the processor 201 to perform any of the cable fault localization methods described above.
In one embodiment of the present invention, the processor 201 is configured to input a first preset detection signal from a head end of a cable to be tested by using the signal generator, and the signal collector collects a detection return signal of the first preset detection signal at the head end of the cable to be tested; the head end of the cable to be tested is a detection end for detecting the cable to be tested; performing Hilbert transform on the detection return signal to obtain a transformed signal, and determining a complex signal to be analyzed based on the transformed signal and the detection return signal; the complex signal to be analyzed is used for analyzing the defect position of the cable to be tested; carrying out correlation comparison on the complex signals to be analyzed and a second preset detection signal to determine the defect position of the cable to be tested; wherein the first preset detection signal is the real part of the second preset detection signal; the second predetermined probing signal is a standard complex probing signal comprising a real part and an imaginary part.
Some embodiments of the invention provide a non-volatile computer storage medium corresponding to one of the cable fault localization of fig. 1, storing computer executable instructions configured to:
the signal generator inputs a first preset detection signal from the head end of the cable to be detected, and the signal collector collects a detection return signal of the first preset detection signal at the head end of the cable to be detected; the head end of the cable to be tested is a detection end for detecting the cable to be tested;
performing Hilbert transform on the detection return signal to obtain a transformed signal, and determining a complex signal to be analyzed based on the transformed signal and the detection return signal; the complex signal to be analyzed is used for analyzing the defect position of the cable to be tested;
carrying out correlation comparison on the complex signals to be analyzed and a second preset detection signal to determine the defect position of the cable to be tested; wherein the first preset detection signal is the real part of the second preset detection signal; the second predetermined probing signal is a standard complex probing signal comprising a real part and an imaginary part.
The embodiments of the present invention are described in a progressive manner, and the same and similar parts of the embodiments are all referred to each other, and each embodiment is mainly described in the differences from the other embodiments. In particular, for the internet of things device and the medium embodiment, since they are substantially similar to the method embodiment, the description is relatively simple, and the relevant points are referred to in the description of the method embodiment.
The system, the medium and the method provided by the embodiment of the invention are in one-to-one correspondence, so that the system and the medium also have similar beneficial technical effects to the corresponding method, and the beneficial technical effects of the method are explained in detail above, so that the beneficial technical effects of the system and the medium are not repeated here.
It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
In one typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.
The memory may include volatile memory in a computer-readable medium, random Access Memory (RAM) and/or nonvolatile memory, such as Read Only Memory (ROM) or flash memory (flash RAM). Memory is an example of computer-readable media.
Computer readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of storage media for a computer include, but are not limited to, phase change memory (PRAM), static Random Access Memory (SRAM), dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), read Only Memory (ROM), electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium, which can be used to store information that can be accessed by a computing device. Computer-readable media, as defined herein, does not include transitory computer-readable media (transmission media), such as modulated data signals and carrier waves.
It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article or apparatus that comprises the element.
The foregoing is merely exemplary of the present invention and is not intended to limit the present invention. Various modifications and variations of the present invention will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the invention are to be included in the scope of the claims of the present invention.
Claims (8)
1. A method for locating a cable defect, the method comprising:
the signal generator inputs a first preset detection signal from the head end of the cable to be detected, and the signal collector collects a detection return signal of the first preset detection signal at the head end of the cable to be detected; the head end of the cable to be tested is a detection end for detecting the cable to be tested;
performing Hilbert transform on the detection return signal to obtain a transformed signal, and determining a complex signal to be analyzed based on the transformed signal and the detection return signal; the complex signal to be analyzed is used for analyzing the defect position of the cable to be tested;
performing correlation comparison on the complex signal to be analyzed and a second preset detection signal to determine the defect position of the cable to be tested; wherein the first preset detection signal is a real part of the second preset detection signal; the second preset detection signal is a standard complex detection signal comprising a real part and an imaginary part;
the complex signal to be analyzed is represented by the following formula:
z(t)＝s r (t)+jH[s r (t)]
wherein z (t) is the complex signal to be analyzed, s r (t) is the detection return signal, hs r (t)]Is a transformed signal;
performing correlation comparison on the complex signal to be analyzed and a second preset detection signal to determine the defect position of the cable to be tested, wherein the method specifically comprises the following steps:
based on a preset correlation function, determining the correlation distribution of the time-frequency distribution of the complex signal to be analyzed and the time-frequency distribution of the second preset detection signal in a time domain; the correlation function is a function taking time as a variable, and the correlation distribution is used for carrying out correlation analysis on the complex signal to be analyzed and the second preset detection signal;
determining a plurality of maxima in the correlation distribution, and determining whether the plurality of maxima are greater than a preset defect amplitude threshold;
determining time parameters of abscissa corresponding to maximum values larger than a preset threshold value in the plurality of maximum values;
and determining the distance from the defect position to the head end of the cable to be tested based on the time parameter of the abscissa.
2. The method of claim 1, wherein the first predetermined detection signal is determined by the following formula:
wherein s is R (t) is a first preset detection signal, t is the output time of the first preset detection signal, alpha is a first constant, t 0 For the central time of the duration of the first preset detection signal in the cable to be detected, beta is a second constant, omega 0 Is the angular frequency center of the first preset detection signal.
3. The method of claim 2, wherein before the signal generator inputs the first predetermined detection signal from the head end of the cable under test, the method further comprises:
calculating the central time t of the duration of the first preset detection signal in the cable to be tested based on the preset normalized Gaussian envelope signal 0 The method comprises the steps of carrying out a first treatment on the surface of the The method comprises the steps of,
calculating the angular frequency center omega of the first preset detection signal based on the first constant and the second constant 0 。
4. The cable fault localization method according to claim 1, wherein the performing hilbert transformation on the probe return signal to obtain a transformed signal, and determining the complex signal to be analyzed based on the transformed signal and the probe return signal, specifically comprises:
rotating the probe return signal by 90 ° clockwise in the frequency domain based on the hilbert transform, thereby obtaining a transformed signal;
the detection return signal is taken as a real part forming a complex signal to be analyzed, and the transformation signal is taken as an imaginary part forming the complex signal to be analyzed, so that the complex signal to be analyzed is obtained.
5. The method of claim 1, wherein prior to correlation comparing the complex signal to be analyzed with a second predetermined probe signal, the method further comprises:
determining the time-frequency distribution of the complex signal to be analyzed based on a wiener distribution function; the method comprises the steps of,
and determining the time-frequency distribution of the second preset detection signal based on the wiener distribution function.
6. The method for locating a cable defect according to claim 1, wherein determining the distance from the defect location to the head end of the cable to be tested based on the time parameter of the abscissa comprises:
among a plurality of maximum values larger than a preset threshold value, determining that the position corresponding to the first maximum value is the head end of the cable to be tested, determining that the position corresponding to the last maximum value is the tail end of the cable to be tested, and determining that the positions corresponding to the maximum values between the first maximum value and the last maximum value are defect positions;
and determining the transmission speed of a first preset detection signal in the cable to be tested based on the performance parameters of the cable to be tested, and determining the specific distance from the defect position to the head end of the cable to be tested based on the transmission speed and the time parameter of the abscissa corresponding to the defect position.
7. A cable fault locating device, the device comprising:
a processor;
and a memory having executable code stored thereon that, when executed, causes the processor to perform a method as claimed in any one of claims 1 to 6.
8. A non-transitory computer storage medium storing computer executable instructions for cable fault localization, the computer executable instructions configured to:
the signal generator inputs a first preset detection signal from the head end of the cable to be detected, and the signal collector collects a detection return signal of the first preset detection signal at the head end of the cable to be detected; the head end of the cable to be tested is a detection end for detecting the cable to be tested;
performing Hilbert transform on the detection return signal to obtain a transformed signal, and determining a complex signal to be analyzed based on the transformed signal and the detection return signal; the complex signal to be analyzed is used for analyzing the defect position of the cable to be tested;
performing correlation comparison on the complex signal to be analyzed and a second preset detection signal to determine the defect position of the cable to be tested; wherein the first preset detection signal is a real part of the second preset detection signal; the second preset detection signal is a standard complex detection signal comprising a real part and an imaginary part;
the complex signal to be analyzed is represented by the following formula:
z(t)＝s r (t)+jH[s r (t)]
wherein z (t) is the complex signal to be analyzed, s r (t) is the detection return signal, hs r (t)]Is a transformed signal;
performing correlation comparison on the complex signal to be analyzed and a second preset detection signal to determine the defect position of the cable to be tested, wherein the method specifically comprises the following steps:
based on a preset correlation function, determining the correlation distribution of the time-frequency distribution of the complex signal to be analyzed and the time-frequency distribution of the second preset detection signal in a time domain; the correlation function is a function taking time as a variable, and the correlation distribution is used for carrying out correlation analysis on the complex signal to be analyzed and the second preset detection signal;
determining a plurality of maxima in the correlation distribution, and determining whether the plurality of maxima are greater than a preset defect amplitude threshold;
determining time parameters of abscissa corresponding to maximum values larger than a preset threshold value in the plurality of maximum values;
and determining the distance from the defect position to the head end of the cable to be tested based on the time parameter of the abscissa.
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