Partial discharge signal positioning method, device and equipment based on signal frequency domain amplitude attenuation characteristics and storage medium

Abstract

The invention discloses a partial discharge signal positioning method, device and equipment based on signal frequency domain amplitude attenuation characteristics, and a storage medium, and the method comprises the steps: obtaining a plurality of end synchronization time domain signals of a to-be-detected cable in a period of time, and obtaining a plurality of signal data sets; taking the pulse signal with the maximum amplitude in each signal data group as a template pulse signal; taking other signal data groups except the signal data group where the template pulse signal is located as to-be-matched signal data groups; pulse signals in the to-be-matched signal data set serve as to-be-matched pulse signals; obtaining a selected pulse signal corresponding to the to-be-matched signal group according to the matching degree of the to-be-matched pulse signal and the template pulse signal; performing Fourier transform on the template pulse signal and the selected pulse signal to determine an amplitude; and positioning the partial discharge signal of the to-be-detected cable according to the amplitude. According to the invention, distortion of signal waveforms can be avoided, and more accurate positioning of partial discharge signals can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of local discharge signal locating, and in particular to a local discharge signal locating method, device, equipment and storage medium based on the signal frequency domain amplitude attenuation characteristic. Background Art

[0002] With the advent of the intelligent information age, electric energy has become an indispensable energy source in people's daily lives, and the reliability of power supply is related to people's daily lives and production lives. In the urban distribution network system, power cables of various voltage levels gradually form a complex distribution network. In the distribution system, the insulation state of the power cable is closely related to the partial discharge of the cable. The high-frequency current transformer method is one of the commonly used methods for detecting and locating partial discharge signals in cables. Its working principle is to detect the high-frequency partial discharge signal flowing through the cable grounding wire through the Rogowski coil current transformer.

[0003] In the prior art, since different frequency components in the partial discharge signal have different propagation speeds and attenuation conditions in the cable, the signal waveform will be distorted, which will in turn affect the positioning accuracy of the partial discharge signal.

[0004] Therefore, how to avoid signal waveform distortion and achieve more accurate positioning of partial discharge signals is an urgent problem to be solved. Summary of the invention

[0005] The present invention provides a local discharge signal positioning method, device, equipment and storage medium based on the signal frequency domain amplitude attenuation characteristic, which can avoid the distortion of the signal waveform and realize more accurate local discharge signal positioning.

[0006] An embodiment of the present invention provides a method for locating a partial discharge signal based on the signal frequency domain amplitude attenuation characteristic, comprising:

[0007] Respectively acquiring a plurality of end-synchronous time domain signals of the cable to be tested within a period of time to obtain a plurality of signal data groups;

[0008] The pulse signal with the largest amplitude in each of the above signal data groups is used as a template pulse signal;

[0009] The signal data group where the template pulse signal is located is used as the selected signal data group, and the other signal data groups except the selected signal data group are used as the signal data group to be matched; each pulse signal in the signal data group to be matched is used as the pulse signal to be matched;

[0010] For each signal group to be matched, the matching degree between each pulse signal to be matched and the template pulse signal in the signal group to be matched is calculated, and the pulse signal to be matched with the highest matching degree is used as the selected pulse signal to obtain the selected pulse signal corresponding to each signal group to be matched;

[0011] For each selected pulse signal corresponding to the signal group to be matched, the template pulse signal and the selected pulse signal are subjected to Fourier transformation to determine amplitudes of several signal components of the template pulse signal and the selected pulse signal at the same frequency;

[0012] The cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance of the cable to be tested are obtained to calculate the distance from the local discharge point to the cable end corresponding to the above-mentioned template pulse signal according to the amplitudes of the above-mentioned signal components, cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance, and the position of the local discharge signal under each selected pulse signal is determined according to the above-mentioned distance.

[0013] Furthermore, before using the pulse signal with the largest amplitude in each of the above signal data groups as the template pulse signal, the method further includes:

[0014] Repeat the pulse extraction operation to extract the pulse signal from the signal data group until the maximum value of the signal in the signal data group is 0, thereby obtaining a plurality of pulse signals;

[0015] Among them, the above pulse extraction operation:

[0016] Find the maximum value point of the signal in the current signal data group; wherein the initial current signal data group is the original signal data group without removing the pulse signal;

[0017] Taking the maximum value point of the above signal as the center, search for the signal zero-crossing point on both sides, take the signal between the zero-crossing points on both sides as a pulse signal, and then extract the pulse signal;

[0018] The extracted pulse signal is removed from the current signal data group to obtain an updated current signal data group.

[0019] Furthermore, for each signal group to be matched, the matching degree between each pulse signal to be matched and the template pulse signal in the signal group to be matched is calculated, and the pulse signal to be matched with the highest matching degree is used as the selected pulse signal to obtain the selected pulse signal corresponding to each signal group to be matched, including:

[0020] For each signal group to be matched, calculating the distance between each sequence element in each pulse signal to be matched in the signal group to be matched and the sequence element of the pulse signal to be matched, and obtaining a distance matrix according to the distance;

[0021] Accumulate the distances between each element in the distance matrix to obtain several accumulated path distances, and extract the shortest path distance;

[0022] Calculating the correlation coefficient between the pulse signal to be matched and the template pulse signal;

[0023] According to the shortest path distance and the correlation coefficient, a matching coefficient between the pulse signal to be matched and the template pulse signal is calculated;

[0024] The matching coefficients between the pulse signals to be matched are compared with each other to obtain the minimum matching coefficient, and the pulse signal to be matched corresponding to the minimum matching coefficient is used as the selected pulse signal, and then the selected pulse signal corresponding to each signal group to be matched is obtained.

[0025] Furthermore, for each selected pulse signal corresponding to the signal group to be matched, the template pulse signal and the selected pulse signal are subjected to Fourier transform to determine the amplitudes of several signal components of the template pulse signal and the selected pulse signal at the same frequency, including:

[0026] Performing Fourier transform on the pulse signal to be processed to obtain a frequency domain signal corresponding to the pulse signal to be processed: wherein the pulse signal to be processed is the template pulse signal or the selected pulse signal corresponding to each of the signal groups to be matched;

[0027] According to the frequency domain signal, the amplitude-frequency characteristic curve of the template pulse signal and the selected pulse signal corresponding to each of the signal groups to be matched is obtained;

[0028] The signal component amplitudes of the template pulse signal and the selected pulse signal corresponding to each of the signal groups to be matched at the same frequency are obtained from the amplitude-frequency characteristic curve.

[0029] Further, the above-mentioned obtaining of the cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance of the cable to be tested to calculate the distance from the partial discharge point to the cable end corresponding to the above-mentioned template pulse signal according to the amplitudes of the above-mentioned signal components, cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance, and determining the position of the partial discharge signal under each selected pulse signal according to the above-mentioned distance, includes:

[0030] According to the above-mentioned distributed resistance, distributed conductance, distributed inductance and distributed capacitance, a signal propagation attenuation coefficient of the signal on the above-mentioned cable to be tested is calculated;

[0031] For each selected pulse signal corresponding to the above-mentioned signal group to be matched, the distance from the local discharge point to the cable end corresponding to the above-mentioned template pulse signal is calculated based on the above-mentioned signal propagation attenuation coefficient, the above-mentioned cable length, and the above-mentioned signal component amplitude, and then the position of the local discharge signal under each selected pulse signal is obtained.

[0032] Based on the above method embodiment, the present invention provides a corresponding device embodiment;

[0033] The present invention provides a local discharge signal locating device based on the signal frequency domain amplitude attenuation characteristic, comprising: a signal acquisition module, a template pulse signal determination module, a to-be-matched pulse signal determination module, a selected pulse signal determination module, a signal component amplitude calculation module and a local discharge signal position calculation module;

[0034] The signal acquisition module is used to respectively acquire a plurality of end-synchronous time domain signals of the cable under test within a period of time to obtain a plurality of signal data groups;

[0035] The template pulse signal determination module is used to use the pulse signal with the largest amplitude in each of the signal data groups as the template pulse signal;

[0036] The above-mentioned pulse signal determination module to be matched is used to take the signal data group where the above-mentioned template pulse signal is located as the selected signal data group, and take other signal data groups except the selected signal data group as the signal data group to be matched; and take each pulse signal in the signal data group to be matched as the pulse signal to be matched;

[0037] The selected pulse signal determination module is used to calculate the matching degree between each pulse signal to be matched and the template pulse signal in each signal group to be matched, and take the pulse signal to be matched with the highest matching degree as the selected pulse signal, so as to obtain the selected pulse signal corresponding to each signal group to be matched;

[0038] The signal component amplitude calculation module is used to perform Fourier transform on the template pulse signal and the selected pulse signal for each selected pulse signal group to be matched, and determine the amplitudes of several signal components of the template pulse signal and the selected pulse signal at the same frequency;

[0039] The above-mentioned local discharge signal position calculation module obtains the cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance of the cable to be tested to calculate the distance from the local discharge point to the cable end corresponding to the above-mentioned template pulse signal according to the amplitudes of the above-mentioned signal components, cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance, and determines the position of the local discharge signal under each selected pulse signal according to the above-mentioned distance.

[0040] Based on the above method embodiment, the present invention provides a terminal device embodiment;

[0041] The present invention provides a terminal device, comprising a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, a method for locating a partial discharge signal based on the signal frequency domain amplitude attenuation characteristic as described in any embodiment of the present invention is implemented.

[0042] Based on the above method embodiment, the present invention provides a storage medium embodiment;

[0043] The present invention provides a storage medium, comprising a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, a method for locating a partial discharge signal based on the signal frequency domain amplitude attenuation characteristic as described in any embodiment of the present invention is implemented.

[0044] The embodiments of the present invention have the following beneficial effects:

[0045] The present invention provides a local discharge signal positioning method, device, equipment and storage medium based on the signal frequency domain amplitude attenuation characteristics. The method first obtains a plurality of end-synchronous time domain signals of the cable to be tested within a period of time to obtain a plurality of signal data groups; then the pulse signal with the largest amplitude in each of the above signal data groups is used as a template pulse signal; then the signal data group where the template pulse signal is located is used as a selected signal data group, and other signal data groups except the selected signal data group are used as signal data groups to be matched; each pulse signal in the signal data group to be matched is used as a pulse signal to be matched; then for each signal group to be matched, the matching degree between each pulse signal to be matched in the signal group to be matched and the template pulse signal is calculated, and the signal with the highest matching degree is selected as the template pulse signal. The pulse signal to be matched is used as the selected pulse signal to obtain the selected pulse signal corresponding to each signal group to be matched; then, for the selected pulse signal corresponding to each signal group to be matched, the template pulse signal and the selected pulse signal are Fourier transformed to determine the amplitudes of several signal components of the template pulse signal and the selected pulse signal at the same frequency; then, the cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance of the cable to be tested are obtained to calculate the distance from the local discharge point to the cable end corresponding to the template pulse signal according to the amplitudes of the several signal components, cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance, and the position of the local discharge signal under each selected pulse signal is determined according to the distance. Therefore, the present invention converts the positioning signal pair from the time domain to the frequency domain through Fourier transform, locates the signal based on the propagation consistency and amplitude-frequency attenuation characteristics of the signal of the same frequency at the same cable terminal, avoids signal distortion in the time domain, thereby reducing the positioning error caused by distortion and improving the accuracy of positioning the local discharge signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a flow chart of a method for locating a partial discharge signal based on the signal frequency domain amplitude attenuation characteristic provided by an embodiment of the invention.

[0047] Figure 2 The present invention is a schematic diagram of double-end signal collection based on GPS time synchronization cable provided by an embodiment of the present invention.

[0048] Figure 3 It is a schematic diagram of a template pulse signal and an amplitude-frequency characteristic curve of a selected pulse signal and Fourier transform thereof provided by an embodiment of the present invention.

[0049] Figure 4 It is a schematic diagram of the structure of a device for locating partial discharge signals based on the signal frequency domain amplitude attenuation characteristics provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0050] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings 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 ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] like Figure 1 As shown, an embodiment of the present invention provides a method for locating a partial discharge signal based on the signal frequency domain amplitude attenuation characteristic, comprising:

[0052] Step S101: acquiring a plurality of end-synchronous time domain signals of the cable to be tested within a period of time respectively, and obtaining a plurality of signal data groups;

[0053] Specifically, Figure 2 As shown, taking the double ends of the cable as an example, a high-frequency current transformer is connected at the grounding wire of the cable at multiple ends, and the signal synchronization acquisition at multiple ends is realized based on the GPS time synchronization system and the host computer control. In the figure, 1 is a satellite antenna, 2 is a host computer, and 3 is a high-frequency current transformer. The signal acquisition unit at the double ends of the cable is controlled by the host computer to simultaneously collect the partial discharge pulse signal of the double ends of the cable within a period of time based on the GPS time synchronization pulse signal, and the collected partial discharge signal is saved locally and uploaded to the host computer, and the partial discharge source is located in the host computer.

[0054] Step S102: taking the pulse signal with the largest amplitude in each of the above signal data groups as a template pulse signal;

[0055] In a preferred embodiment, before using the pulse signal with the largest amplitude in each of the above signal data groups as the template pulse signal, the method further includes:

[0056] Repeat the pulse extraction operation to extract the pulse signal from the signal data group until the maximum value of the signal in the signal data group is 0, thereby obtaining a plurality of pulse signals;

[0057] Among them, the above pulse extraction operation:

[0058] Find the maximum value point of the signal in the current signal data group; wherein the initial current signal data group is the original signal data group without removing the pulse signal;

[0059] Taking the maximum value point of the above signal as the center, search for the signal zero-crossing point on both sides, take the signal between the zero-crossing points on both sides as a pulse signal, and then extract the pulse signal;

[0060] The extracted pulse signal is removed from the current signal data group to obtain an updated current signal data group.

[0061] In this preferred embodiment, the pulse signal is extracted from the signal data group by repeatedly performing the pulse extraction operation until the maximum signal value in the signal data group is 0, thereby obtaining several pulse signals, and then the pulse signal with the largest amplitude is compared from the several pulse signals as the template pulse signal.

[0062] Step S103: taking the signal data group where the template pulse signal is located as the selected signal data group, taking other signal data groups except the selected signal data group as the signal data group to be matched; taking each pulse signal in the signal data group to be matched as the pulse signal to be matched;

[0063] In this step, the signal data group containing the template pulse signal is taken as the selected signal data group, and the other signal data groups except the selected signal data group are taken as the signal data groups to be matched; each pulse signal in the signal data group to be matched is taken as the pulse signal to be matched.

[0064] Step S104: for each signal group to be matched, calculating the matching degree between each pulse signal to be matched in the signal group to be matched and the template pulse signal, taking the pulse signal to be matched with the highest matching degree as the selected pulse signal, and obtaining the selected pulse signal corresponding to each signal group to be matched;

[0065] In a preferred embodiment, for each signal group to be matched, the matching degree between each pulse signal to be matched and the template pulse signal in the signal group to be matched is calculated, and the pulse signal to be matched with the highest matching degree is used as the selected pulse signal to obtain the selected pulse signal corresponding to each signal group to be matched, including:

[0066] For each signal group to be matched, calculating the distance between each sequence element in each pulse signal to be matched in the signal group to be matched and the sequence element of the pulse signal to be matched, and obtaining a distance matrix according to the distance;

[0067] Preferably, the DTW signal analysis method is combined with the correlation coefficient method to obtain the matching coefficient between each pulse signal to be matched in the signal group to be matched and the template pulse signal.

[0068] Specifically, the distances between each sequence element in each pulse signal to be matched in the above-mentioned signal group to be matched and the sequence element of the above-mentioned pulse signal to be matched are calculated by the following formula, and a distance matrix is ​​obtained according to the above-mentioned distances:

[0069] M(i,j)=(S(i)-T l (j)) 2 ;

[0070] Wherein, M represents the distance matrix, M(i,j) represents the distance between the i-th sequence element of the template pulse signal and the j-th sequence element of the l-th pulse signal in the pulse signal set to be matched, S(i) represents the i-th sequence element of the template pulse signal, T l (j) represents the jth sequence element of the lth pulse signal to be matched in the above-mentioned signal group to be matched.

[0071] Accumulate the distances between each element in the distance matrix to obtain several accumulated path distances, and extract the shortest path distance;

[0072] Specifically, the shortest path distance is calculated by the following formula:

[0073]

[0074] Where D represents the shortest path distance, f(i k ,j k ) represents the regularization function, i k represents the element in the kth row of the distance matrix above, j k represents the element located in the kth column of the above distance matrix, M(i k ,j k ) represents the element located in the kth row and kth column of the above distance matrix.

[0075] Preferably, the size of D can reflect the matching degree between the template pulse signal and each pulse signal to be matched in each signal group to be matched.

[0076] Calculating the correlation coefficient between the pulse signal to be matched and the template pulse signal;

[0077] Specifically, the above correlation coefficient is calculated by the following formula:

[0078]

[0079] In the formula, ρ x,y represents the above correlation coefficient, x(t) represents the above template pulse signal, and y(t) represents the pulse signal in the above pulse signal set to be matched.

[0080] According to the shortest path distance and the correlation coefficient, a matching coefficient between the pulse signal to be matched and the template pulse signal is calculated;

[0081] Specifically, the matching coefficient is calculated by the following formula:

[0082] k=a·D+(1-a)·ρ x,y ;

[0083] In the formula, k represents the above matching coefficient, a represents the weighting coefficient, and the weighting coefficient can be set according to the actual cable operation conditions.

[0084] The matching coefficients between the pulse signals to be matched are compared with each other to obtain the minimum matching coefficient, and the pulse signal to be matched corresponding to the minimum matching coefficient is used as the selected pulse signal, and then the selected pulse signal corresponding to each signal group to be matched is obtained.

[0085] Preferably, through this preferred embodiment, the recognition accuracy of the template pulse signal and the selected pulse signal belonging to the same local discharge from the collected cable signal is effectively improved, while the problem of low recognition and matching accuracy caused by the inconsistent degree of distortion of the local discharge signal waveform arriving at several ends of the cable due to the local discharge signal position being biased towards one end is effectively improved.

[0086] In this preferred embodiment, the distance between each sequence element in each pulse signal to be matched in the signal group to be matched and the sequence element of the above pulse signal to be matched is calculated, and then the shortest path distance between each element in the distance matrix is ​​calculated, and then the correlation coefficient between the pulse signal to be matched and the template pulse signal is calculated, and finally the matching coefficient between the pulse signal to be matched and the template pulse signal is calculated by the shortest path distance and the above correlation coefficient, and finally the pulse signal to be matched corresponding to the minimum matching coefficient is obtained, and finally the selected pulse signal corresponding to each signal group to be matched is obtained.

[0087] Step S105: for each selected pulse signal corresponding to the signal group to be matched, the template pulse signal and the selected pulse signal are subjected to Fourier transform to determine amplitudes of several signal components of the template pulse signal and the selected pulse signal at the same frequency;

[0088] In a preferred embodiment, for each selected pulse signal corresponding to the signal group to be matched, the template pulse signal and the selected pulse signal are subjected to Fourier transform to determine the amplitudes of several signal components of the template pulse signal and the selected pulse signal at the same frequency, including:

[0089] Performing Fourier transform on the pulse signal to be processed to obtain a frequency domain signal corresponding to the pulse signal to be processed: wherein the pulse signal to be processed is the template pulse signal or the selected pulse signal corresponding to each of the signal groups to be matched;

[0090] Specifically, the pulse signal to be processed is subjected to Fourier transform by the following formula:

[0091]

[0092] In the formula, F(jω) represents the pulse signal to be processed after Fourier transform, and f(t) represents the pulse signal to be processed in the time domain.

[0093] According to the frequency domain signal, the amplitude-frequency characteristic curve of the template pulse signal and the selected pulse signal corresponding to each of the signal groups to be matched is obtained;

[0094] The signal component amplitudes of the template pulse signal and the selected pulse signal corresponding to each of the signal groups to be matched at the same frequency are obtained from the amplitude-frequency characteristic curve.

[0095] Indicatively, Figure 3 As shown, Figure 3 Part a is a schematic diagram of the amplitude-frequency characteristic curve of the template pulse signal in the time domain, where U m represents the voltage amplitude of the above template pulse signal, Figure 3 Part b is a schematic diagram of the amplitude-frequency characteristic curve of a selected pulse signal in the time domain, where U t represents the voltage amplitude of the above selected pulse signal, Figure 3 Part c is the frequency domain diagram of the template pulse signal in the time domain after Fourier transformation. Figure 3 Part d is a frequency domain diagram of a selected pulse signal in the above time domain after Fourier transform.

[0096] Preferably, assuming that the selected signal frequencies are f1, f2, ..., f n In order to ensure the effectiveness of the signal, the maximum frequency fn should be less than 30MHz to prevent the noise caused by it from interfering with the positioning results. n The template pulse signal U m The signal component amplitude is recorded as U m1 , U m2 , …, U mn , U t1 , a selected pulse signal U t The signal component amplitude is recorded as U t2 , …, U tn .

[0097] In this preferred embodiment, a template pulse signal in the frequency domain and a selected pulse signal corresponding to each signal group to be matched are obtained through Fourier transform, and then several signal component amplitudes of the template pulse signal and the selected pulse signal corresponding to each signal group to be matched at the same frequency are obtained.

[0098] Step S106: Obtain the cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance of the cable to be tested, and calculate the distance from the partial discharge point to the cable end corresponding to the template pulse signal according to the amplitudes of the above signal components, cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance, and determine the position of the partial discharge signal under each selected pulse signal according to the above distance;

[0099] In a preferred embodiment, the cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance of the cable to be tested are obtained to calculate the distance from the local discharge point to the cable end corresponding to the template pulse signal according to the amplitudes of the signal components, the cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance, and the position of the local discharge signal under each selected pulse signal is determined according to the distance, including:

[0100] According to the above-mentioned distributed resistance, distributed conductance, distributed inductance and distributed capacitance, a signal propagation attenuation coefficient of the signal on the above-mentioned cable to be tested is calculated;

[0101] Specifically, the signal propagation attenuation coefficient of the signal in the cable to be tested is calculated by the following formula:

[0102]

[0103] In the formula, α represents the signal propagation attenuation coefficient, and the α value is related to the signal frequency. Therefore, for a signal of a certain frequency, α can be considered as a constant, R0 represents the distributed resistance, G0 represents the distributed conductance, ω0 represents the angular frequency, L0 represents the distributed inductance, and C0 represents the distributed capacitance.

[0104] For each selected pulse signal corresponding to the above-mentioned signal group to be matched, the distance from the local discharge point to the cable end corresponding to the above-mentioned template pulse signal is calculated based on the above-mentioned signal propagation attenuation coefficient, the above-mentioned cable length, and the above-mentioned signal component amplitude, and then the position of the local discharge signal under each selected pulse signal is obtained.

[0105] Specifically, according to the transmission line theory, the amplitude attenuation of a single frequency signal when it is transmitted in a cable conforms to the exponential attenuation law. Therefore, the attenuation law of a single frequency signal can be obtained by the following formula:

[0106] U0=U i e -αl ;

[0107] Where U i Represents the initial voltage amplitude of a single frequency signal; U o Represents the voltage amplitude of the above single frequency signal after propagating l distance.

[0108] Specifically, when the number of ends is two ends, the position of the local discharge signal under the selected pulse signal is taken as the final position of the local discharge signal of the cable under test; when the number of ends is more than two ends, according to the position of the local discharge signal under each selected pulse signal, the number of occurrences of each position is counted, and the position with the largest number of times is taken as the final position of the local discharge signal of the cable under test.

[0109] Specifically, therefore, when the number of terminals is two terminals, the distance from the partial discharge to the cable end corresponding to the template pulse signal can be calculated by the following formula:

[0110]

[0111] When the number of terminals is more than two, the distance from the local discharge point corresponding to each selected pulse signal to the cable end corresponding to the template pulse signal can be calculated by the following formula:

[0112]

[0113] In the formula, l i represents the distance from the local discharge point to the cable end corresponding to the template pulse signal when the number of terminals is two terminals, l represents the distance from the local discharge point corresponding to each selected pulse signal to the cable end corresponding to the template pulse signal when the number of terminals is more than two terminals, L represents the cable length, U mi represents the signal component amplitude of the above template pulse signal at frequency i, U ti represents the signal component amplitude of the above selected pulse signal at frequency i, ε i Represents the weighting coefficient. The weighting coefficients at each frequency are the same, all 1 / n, and satisfy

[0114] In this preferred embodiment, the position of the partial discharge signal under each selected pulse signal is obtained through the amplitudes of the above-mentioned signal components, cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance.

[0115] In this step, the final position of the partial discharge signal of the cable to be tested is obtained by analyzing the position of the partial discharge signal obtained.

[0116] Based on the above method embodiment, the present invention provides a corresponding device embodiment.

[0117] like Figure 4 As shown, an embodiment of the present invention provides a device for locating a partial discharge signal based on the signal frequency domain amplitude attenuation characteristic, comprising:

[0118] A signal acquisition module, a template pulse signal determination module, a to-be-matched pulse signal determination module, a selected pulse signal determination module, a signal component amplitude calculation module, and a partial discharge signal position calculation module;

[0119] The signal acquisition module is used to respectively acquire a plurality of end-synchronous time domain signals of the cable under test within a period of time to obtain a plurality of signal data groups;

[0120] The template pulse signal determination module is used to use the pulse signal with the largest amplitude in each of the signal data groups as the template pulse signal;

[0121] The above-mentioned pulse signal determination module to be matched is used to take the signal data group where the above-mentioned template pulse signal is located as the selected signal data group, and take other signal data groups except the selected signal data group as the signal data group to be matched; and take each pulse signal in the signal data group to be matched as the pulse signal to be matched;

[0122] The selected pulse signal determination module is used to calculate the matching degree between each pulse signal to be matched and the template pulse signal in each signal group to be matched, and take the pulse signal to be matched with the highest matching degree as the selected pulse signal, so as to obtain the selected pulse signal corresponding to each signal group to be matched;

[0123] The signal component amplitude calculation module is used to perform Fourier transform on the template pulse signal and the selected pulse signal for each selected pulse signal group to be matched, and determine the amplitudes of several signal components of the template pulse signal and the selected pulse signal at the same frequency;

[0124] The above-mentioned local discharge signal position calculation module obtains the cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance of the cable to be tested to calculate the distance from the local discharge point to the cable end corresponding to the above-mentioned template pulse signal according to the amplitudes of the above-mentioned signal components, cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance, and determines the position of the local discharge signal under each selected pulse signal according to the above-mentioned distance.

[0125] It should be noted that the device embodiments described above are merely schematic, wherein the modules described above as separate components may or may not be physically separated, and the components displayed as modules may or may not be physical modules, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. In addition, in the accompanying drawings of the device embodiments provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, which may be specifically implemented as one or more communication buses or signal lines. A person of ordinary skill in the art may understand and implement it without creative work. The above schematic diagram is only an example of a local discharge signal locating device based on the signal frequency domain amplitude attenuation characteristic, and does not constitute a limitation on a local discharge signal locating device based on the signal frequency domain amplitude attenuation characteristic, and may include more or fewer components than shown in the figure, or combine certain components, or different components.

[0126] Based on the above method item embodiments, the present invention provides corresponding terminal device item embodiments.

[0127] Another embodiment of the present invention provides a terminal device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, a method for locating a partial discharge signal based on the signal frequency domain amplitude attenuation characteristics as described in any embodiment of the present invention is implemented.

[0128] Exemplarily, in this embodiment, the computer program may be divided into one or more modules, which are stored in the memory and executed by the processor to implement the present invention. The one or more modules may be a series of computer program instruction segments capable of implementing specific functions, which are used to describe the execution process of the computer program in the device;

[0129] The terminal device may be a computing device such as a desktop computer, a notebook, a PDA, a cloud server, etc. The device may include, but is not limited to, a processor, a memory;

[0130] The processor referred to herein may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc. The above-mentioned processor is the control center of the above-mentioned device, and uses various interfaces and lines to connect various parts of the entire device;

[0131] The above-mentioned memory can be used to store the above-mentioned computer programs and / or modules. The above-mentioned processor realizes various functions of the above-mentioned device by running or executing the computer programs and / or modules stored in the above-mentioned memory, and calling the data stored in the memory. The above-mentioned memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, at least one application required for a function, etc.; in addition, the memory can include a high-speed random access memory, and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0132] Based on the above method item embodiments, the present invention provides a corresponding storage medium item embodiment.

[0133] Another embodiment of the present invention provides a storage medium, which includes a stored computer program, wherein when the computer program is running, the device where the storage medium is located is controlled to execute a partial discharge signal locating method based on the signal frequency domain amplitude attenuation characteristics as described in any embodiment of the present invention.

[0134] In this embodiment, the storage medium is a computer-readable storage medium, the computer program includes computer program code, and the computer program code may be in source code form, object code form, executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc.

[0135] Compared with the prior art, by implementing the above-mentioned embodiments of the present invention, the distortion of the signal waveform can be avoided and more accurate positioning of the partial discharge signal can be achieved.

[0136] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for locating partial discharge signals based on the signal frequency domain amplitude attenuation characteristics, characterized in that: include: Respectively acquiring a plurality of end-synchronous time domain signals of the cable to be tested within a period of time to obtain a plurality of signal data groups; Using the pulse signal with the largest amplitude in each of the signal data groups as a template pulse signal; The signal data group where the template pulse signal is located is used as the selected signal data group, and the other signal data groups except the selected signal data group are used as the signal data groups to be matched; each pulse signal in the signal data group to be matched is used as the pulse signal to be matched; For each signal group to be matched, the matching degree between each pulse signal to be matched and the template pulse signal in the signal group to be matched is calculated, and the pulse signal to be matched with the highest matching degree is used as the selected pulse signal to obtain the selected pulse signal corresponding to each signal group to be matched; For each selected pulse signal corresponding to the signal group to be matched, the template pulse signal and the selected pulse signal are subjected to Fourier transform to determine amplitudes of several signal components of the template pulse signal and the selected pulse signal at the same frequency; The cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance of the cable to be tested are obtained to calculate the distance from the local discharge point to the cable end corresponding to the template pulse signal according to the amplitudes of the several signal components, the cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance, and the position of the local discharge signal under each selected pulse signal is determined according to the distance.

2. A method for locating partial discharge signals based on the signal frequency domain amplitude attenuation characteristics according to claim 1, characterized in that: Before taking the pulse signal with the largest amplitude in each of the signal data groups as the template pulse signal, the method further includes: Repeat the pulse extraction operation to extract the pulse signal from the signal data group until the maximum value of the signal in the signal data group is 0, thereby obtaining a plurality of pulse signals; Wherein, the pulse extraction operation: Find the maximum value point of the signal in the current signal data group; wherein the initial current signal data group is the original signal data group without removing the pulse signal; Taking the maximum value point of the signal as the center, searching for the signal zero-crossing point on both sides, treating the signal between the zero-crossing points on both sides as a pulse signal, and then extracting the pulse signal; The extracted pulse signal is removed from the current signal data group to obtain an updated current signal data group.

3. A method for locating partial discharge signals based on the signal frequency domain amplitude attenuation characteristics according to claim 2, characterized in that: For each signal group to be matched, the matching degree between each pulse signal to be matched and the template pulse signal in the signal group to be matched is calculated, and the pulse signal to be matched with the highest matching degree is used as the selected pulse signal to obtain the selected pulse signal corresponding to each signal group to be matched, including: For each signal group to be matched, calculating the distance between each sequence element in each pulse signal to be matched in the signal group to be matched and the sequence element of the pulse signal to be matched, and obtaining a distance matrix according to the distance; Accumulate the distances between each element in the distance matrix to obtain a number of accumulated path distances, and extract the shortest path distance; Calculating and obtaining the correlation coefficient between the pulse signal to be matched and the template pulse signal; Calculating a matching coefficient between the pulse signal to be matched and the template pulse signal according to the shortest path distance and the correlation coefficient; The matching coefficients between the pulse signals to be matched are compared with each other to obtain the minimum matching coefficient, and the pulse signal to be matched corresponding to the minimum matching coefficient is used as the selected pulse signal, and then the selected pulse signal corresponding to each signal group to be matched is obtained.

4. A method for locating partial discharge signals based on the signal frequency domain amplitude attenuation characteristic according to claim 3, characterized in that: For each selected pulse signal corresponding to the signal group to be matched, the template pulse signal and the selected pulse signal are subjected to Fourier transform to determine amplitudes of several signal components of the template pulse signal and the selected pulse signal at the same frequency, including: Performing Fourier transform on the pulse signal to be processed to obtain a frequency domain signal corresponding to the pulse signal to be processed: wherein the pulse signal to be processed is the template pulse signal or a selected pulse signal corresponding to each of the signal groups to be matched; According to the frequency domain signal, an amplitude-frequency characteristic curve of the template pulse signal and the selected pulse signal corresponding to each of the signal groups to be matched is obtained; The signal component amplitudes of the template pulse signal and the selected pulse signal corresponding to each signal group to be matched at the same frequency are obtained from the amplitude-frequency characteristic curve.

5. A method for locating partial discharge signals based on the signal frequency domain amplitude attenuation characteristics according to claim 4, characterized in that: The obtaining of the cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance of the cable to be tested to calculate the distance from the local discharge point to the cable end corresponding to the template pulse signal according to the amplitudes of the plurality of signal components, the cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance, and determining the position of the local discharge signal under each selected pulse signal according to the distance, comprises: Calculate the signal propagation attenuation coefficient of the signal on the cable to be tested according to the distributed resistance, distributed conductance, distributed inductance and distributed capacitance; For the selected pulse signal corresponding to each of the signal groups to be matched, the distance from the local discharge point to the cable end corresponding to the template pulse signal is calculated based on the signal propagation attenuation coefficient, the cable length, and the signal component amplitude, and then the position of the local discharge signal under each selected pulse signal is obtained.

6. A local discharge signal locating device based on the signal frequency domain amplitude attenuation characteristic, characterized in that: include: A signal acquisition module, a template pulse signal determination module, a to-be-matched pulse signal determination module, a selected pulse signal determination module, a signal component amplitude calculation module, and a partial discharge signal position calculation module; The signal acquisition module is used to respectively acquire a plurality of end-synchronous time domain signals of the cable to be tested within a period of time to obtain a plurality of signal data groups; The template pulse signal determination module is used to use the pulse signal with the largest amplitude in each of the signal data groups as the template pulse signal; The to-be-matched pulse signal determination module is used to take the signal data group where the template pulse signal is located as the selected signal data group, and take other signal data groups except the selected signal data group as the to-be-matched signal data group; and take each pulse signal in the to-be-matched signal data group as the to-be-matched pulse signal; The selected pulse signal determination module is used to calculate the matching degree between each pulse signal to be matched and the template pulse signal in each signal group to be matched, and take the pulse signal to be matched with the highest matching degree as the selected pulse signal to obtain the selected pulse signal corresponding to each signal group to be matched; The signal component amplitude calculation module is used to perform Fourier transform on the template pulse signal and the selected pulse signal for each selected pulse signal group to be matched, and determine the amplitudes of several signal components of the template pulse signal and the selected pulse signal at the same frequency; The local discharge signal position calculation module obtains the cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance of the cable to be tested, and calculates the distance from the local discharge point to the cable end corresponding to the template pulse signal according to the amplitudes of the several signal components, the cable length, distributed resistance, distributed conductance, distributed inductance and distributed capacitance, and determines the position of the local discharge signal under each selected pulse signal according to the distance.

7. A terminal device, characterized in that: The method comprises a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein when the processor executes the computer program, a method for locating a partial discharge signal based on the signal frequency domain amplitude attenuation characteristic as claimed in any one of claims 1 to 5 is implemented.

8. A storage medium, characterized in that: The storage medium includes a stored computer program, wherein when the computer program is executed, the device where the storage medium is located is controlled to execute a partial discharge signal locating method based on the signal frequency domain amplitude attenuation characteristic as claimed in any one of claims 1 to 5.

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