Method and system for discriminating linear relationship of functions of ultra-high frequency partial discharge sensing system

Abstract

The present invention discloses a method and system for determining the linear relationship of a function of a very high frequency partial discharge sensing system, including: decomposing a broadband electric field signal and an output voltage signal of a very high frequency sensor into a plurality of first sub-band signals and a plurality of second sub-band signals with non-overlapping frequency bands respectively; performing noise judgment on each first sub-band signal and second sub-band signal respectively, and removing the first sub-band signals and second sub-band signals determined to be noise; calculating the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-frequency band according to the remaining first sub-band signals and second sub-band signals; determining that the transfer function of the very high frequency sensor is a linear relationship according to the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-frequency band. The present invention realizes the determination of the linearity of the sensor by calculating the variance of the amplitude flatness and group delay of the transfer function in the effective sub-frequency band, and solves the problem that the linear determination of the very high frequency sensor is often ignored or difficult to calculate.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical equipment testing, and more particularly, to a method and system for determining the linear relationship of the function of a UHF partial discharge sensing system. Background Art

[0002] Measuring partial discharge in the insulation of high-voltage electrical equipment is a common means of evaluating the insulation status of the equipment. Partial discharge measurement techniques include the traditional pulse current method, as well as a series of new live detection techniques such as the UHF method, the high-frequency method, and the ultrasonic method. Among them, the UHF partial discharge detection technique has appropriate quantitative and positioning capabilities and portability, and has been increasingly widely used.

[0003] However, due to the different design principles of UHF sensors, the frequency dispersion effect of the sensors causes distortion of the output signals. Therefore, whether the sensor meets the linear requirements in the signal system directly affects subsequent signal processing and pattern analysis. Currently, little consideration is given to whether the UHF sensor is linear, and the influence of this factor on the measurement results is usually ignored. A method is needed to determine the linear relationship of the sensing system function of the UHF sensor. Summary of the Invention

[0004] The present invention provides a method and system for determining the linear relationship of the function of a UHF partial discharge sensing system to solve the problem of how to determine the linear relationship of the sensing system function of the UHF sensor.

[0005] To solve the above problems, according to one aspect of the present invention, a method for determining the linear relationship of the function of a UHF partial discharge sensing system is provided. The method includes:

[0006] Decomposing a broadband electric field signal and the output voltage signal of a UHF sensor into a plurality of first sub-band signals and a plurality of second sub-band signals with non-overlapping frequency bands respectively;

[0007] Judging the noise of each first sub-band signal and second sub-band signal respectively, and removing the first sub-band signals and second sub-band signals determined to be noise;

[0008] Calculating the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-frequency band according to the remaining first sub-band signals and second sub-band signals;

[0009] Determining that the transfer function of the UHF sensor is a linear relationship according to the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-frequency band.

[0010] Preferably, in the method, the broadband electric field signal and the output voltage signal of the UHF sensor are respectively decomposed into a plurality of first sub-band signals and a plurality of second sub-band signals with non-overlapping frequency bands based on wavelet packet decomposition.

[0011] Preferably, the method determines whether any first sub-band signal and second sub-band signal are noise by the following method, including:

[0012] Calculating the kurtosis operator value of any sub-band signal, and when the kurtosis operator value is less than a preset kurtosis operator threshold, determining that the any sub-band signal is noise;

[0013] Wherein, the kurtosis operator value of any sub-band signal is determined by the following method, including:

[0014]

[0015] Wherein, kurtosis(X) represents the kurtosis operator corresponding to X; X is the sub-band signal obtained after wavelet packet decomposition of the broadband electric field signal or the output voltage signal of the UHF sensor; x p and respectively represent the value of the p-th sampling point and the mean value, n is the total number of sampling points; μ and σ respectively represent the expectation and standard deviation of X.

[0016] Preferably, calculating the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-frequency band according to the remaining first sub-band signals and second sub-band signals, including:

[0017]

[0018] τ eff,i =|t e(t),i -t u(t),i |,

[0019] Wherein, |H eff,i | is the amplitude flatness corresponding to the transfer function in the i-th effective sub-frequency band; |e max,i (t)| is the modulus maximum value of the i-th first sub-band signal corresponding to the broadband electric field signal; |u max,i (t)| is the modulus maximum value of the i-th second sub-band signal corresponding to the output voltage signal of the UHF sensor; τ eff,i is the group delay flatness corresponding to the transfer function in the i-th effective sub-frequency band; t e(t),i is the pulse start point time of the i-th first sub-band signal corresponding to the broadband electric field signal; t u(t),i is the pulse start point time of the i-th second sub-band signal corresponding to the output voltage signal of the UHF sensor.

[0020] Preferably, determining that the transfer function of the UHF sensor is a linear relationship according to the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-band includes:

[0021] Calculating the amplitude flatness variance and group delay flatness variance according to the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-band;

[0022] When the amplitude flatness variance is within a first preset range and the group delay flatness variance is within a second preset range, determining that the transfer function of the UHF sensor is a linear relationship; otherwise, determining that the transfer function of the UHF sensor is a non-linear relationship.

[0023] According to another aspect of the present invention, there is provided a discrimination system for the linear relationship of the UHF partial discharge sensing system function, the system comprising:

[0024] A signal decomposition unit, configured to decompose the broadband electric field signal and the output voltage signal of the UHF sensor into a plurality of first sub-band signals and a plurality of second sub-band signals with non-overlapping frequency bands respectively;

[0025] A noise rejection unit, configured to perform noise judgment on each first sub-band signal and second sub-band signal respectively, and reject the first sub-band signals and second sub-band signals determined to be noise;

[0026] A calculation unit, configured to calculate the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-band according to the remaining first sub-band signals and second sub-band signals;

[0027] A linear relationship determination unit, configured to determine that the transfer function of the UHF sensor is a linear relationship according to the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-band.

[0028] Preferably, the signal decomposition unit decomposes the broadband electric field signal and the output voltage signal of the UHF sensor into a plurality of first sub-band signals and a plurality of second sub-band signals with non-overlapping frequency bands respectively based on wavelet packet decomposition.

[0029] Preferably, the noise rejection unit determines whether any first sub-band signal and second sub-band signal are noise by using the following method, including:

[0030] Calculating the kurtosis operator value of any sub-band signal, and when the kurtosis operator value is less than a preset kurtosis operator threshold, determining that the any sub-band signal is noise;

[0031] Wherein, the kurtosis operator value of any sub-band signal is determined by using the following method, including:

[0032]

[0033] Among them, kurtosis(X) represents the kurtosis operator corresponding to X; X is the sub-band signal obtained after wavelet packet decomposition of the broadband electric field signal or the output voltage signal of the UHF sensor; x p and respectively represent the value and the mean value of the p-th sampling point, and n is the total number of sampling points; μ and σ respectively represent the expectation and the standard deviation of X.

[0034] Preferably, the calculation unit calculates the amplitude flatness and the group delay flatness corresponding to the transfer function in each effective sub-frequency band according to the remaining first sub-band signal and the second sub-band signal, including:

[0035]

[0036] τ eff,i =|t e(t),i -t u(t),i |,

[0037] where, |H eff,i | is the amplitude flatness corresponding to the transfer function in the i-th effective sub-frequency band; |e max,i (t)| is the modulus maximum value of the i-th first sub-band signal corresponding to the broadband electric field signal; |u max,i (t)| is the modulus maximum value of the i-th second sub-band signal corresponding to the output voltage signal of the UHF sensor; τ eff,i is the group delay flatness corresponding to the transfer function in the i-th effective sub-frequency band; t e(t),i is the pulse start point time of the i-th first sub-band signal corresponding to the broadband electric field signal; t u(t),i is the pulse start point time of the i-th second sub-band signal corresponding to the output voltage signal of the UHF sensor.

[0038] Preferably, the linear relationship determination unit determines that the transfer function of the UHF sensor is a linear relationship according to the amplitude flatness and the group delay flatness corresponding to the transfer function in each effective sub-frequency band, including:

[0039] Calculate the amplitude flatness variance and the group delay flatness variance according to the amplitude flatness and the group delay flatness corresponding to the transfer function in each effective sub-frequency band;

[0040] When the amplitude flatness variance is within the first preset range and the group delay flatness variance is within the second preset range, determine that the transfer function of the UHF sensor is a linear relationship, otherwise, determine that the transfer function of the UHF sensor is a non-linear relationship.

[0041] The present invention provides a method and system for discriminating the linear relationship of the ultra-high frequency partial discharge sensing system function. By denoising complex signals on-site, the simultaneous decomposition of the low-frequency part and the high-frequency part of the signal is achieved, improving the time-domain and frequency-domain resolutions; the transfer function considering the frequency dispersion problem of the sensor is clarified, the relationship between frequency dispersion and the linearity of the sensor is pointed out, and the key influencing parameters of the measurement ability of the ultra-high frequency sensor are clarified; by calculating the amplitude flatness of the transfer function and the variance of the group delay within the effective sub-band, the determination of the linearity of the sensor is realized, solving the problem that the linear determination of the ultra-high frequency sensor is often ignored or difficult to calculate. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The exemplary embodiments of the present invention can be more fully understood by referring to the following drawings:

[0043] Figure 1 FIG. is a flowchart of a method 100 for discriminating the linear relationship of the ultra-high frequency partial discharge sensing system function according to an embodiment of the present invention;

[0044] Figure 2 FIG. is a schematic diagram of wavelet packet decomposition according to an embodiment of the present invention;

[0045] Figure 3 FIG. is a schematic structural diagram of a system 300 for discriminating the linear relationship of the ultra-high frequency partial discharge sensing system function according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] Now, the exemplary embodiments of the present invention will be described with reference to the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely, and to fully convey the scope of the present invention to those skilled in the art. The terms in the exemplary embodiments shown in the drawings are not intended to limit the present invention. In the drawings, the same unit / element is denoted by the same reference numeral.

[0047] Unless otherwise specified, the terms (including scientific and technical terms) used herein have the ordinary meaning understood by those skilled in the art. Additionally, it can be understood that the terms defined in the commonly used dictionary should be understood to have a meaning consistent with the context of their related fields, and should not be understood as idealized or overly formal meanings.

[0048] Figure 1 FIG. is a flowchart of a method 100 for discriminating the linear relationship of the ultra-high frequency partial discharge sensing system function according to an embodiment of the present invention. As Figure 1As shown, the method for discriminating the linear relationship of the function of the UHF partial discharge sensing system provided by the embodiment of the present invention realizes the simultaneous decomposition of the low-frequency part and the high-frequency part of the signal through denoising of the complex on-site signal, improving the time-domain and frequency-domain resolutions; clarifies the transfer function considering the frequency dispersion problem of the sensor, points out the relationship between frequency dispersion and the linearity of the sensor, and clarifies the key influencing parameters of the measurement ability of the UHF sensor; realizes the determination of the linearity of the sensor by calculating the amplitude flatness and the variance of the group delay within the effective sub-band, solving the problem that the linearity determination of the UHF sensor is often ignored or difficult to calculate. The method 100 for discriminating the linear relationship of the function of the UHF partial discharge sensing system provided by the embodiment of the present invention starts from step 101. At step 101, the broadband electric field signal and the output voltage signal of the UHF sensor are respectively decomposed into a plurality of first sub-band signals and a plurality of second sub-band signals with non-overlapping frequency bands.

[0049] Preferably, in the method, the broadband electric field signal and the output voltage signal of the UHF sensor are respectively decomposed into a plurality of first sub-band signals and a plurality of second sub-band signals with non-overlapping frequency bands based on wavelet packet decomposition.

[0050] Since the broadband pulse signal collected by the UHF sensor often contains multiple characteristic frequency bands, the method of the present invention uses time-domain signal decomposition technology to decompose the broadband electric field signal e(t) and the output voltage signal u(t) of the UHF sensor into a series of sub-band signals with non-overlapping frequency bands, and eliminates the noise components therein; then, by calculating the amplitude flatness and the group delay flatness of the corresponding sub-band signals in e(t) and u(t), it is determined whether the UHF sensor is a linear system.

[0051] Wavelet packet decomposition is generated and developed on the basis of wavelet transform. In contrast, wavelet packet decomposition is a more refined decomposition method, which realizes the simultaneous decomposition of the low-frequency part and the high-frequency part of the signal, improving the time-domain and frequency-domain resolutions.

[0052] Therefore, in the embodiment of the present invention, based on wavelet packet decomposition, the broadband electric field signal e(t) and the output voltage signal u(t) of the UHF sensor are decomposed in the frequency domain according to frequency, and decomposed into a plurality of first sub-band signals and a plurality of second sub-band signals with non-overlapping frequency bands. As Figure 2 shown, it shows the 3-layer wavelet packet decomposition process of signal X, and finally the signal will be decomposed into sub-band signals of 8 consecutive frequency bands.

[0053] At step 102, noise judgment is respectively performed on each first sub-band signal and second sub-band signal, and the first sub-band signals and second sub-band signals determined to be noise are eliminated.

[0054] Preferably, the method determines whether any first sub-band signal and second sub-band signal are noise in the following manner, including:

[0055] Calculating the kurtosis operator value of any sub-band signal, and when the kurtosis operator value is less than a preset kurtosis operator threshold, determining that the any sub-band signal is noise;

[0056] Among them, the method for determining the kurtosis operator value of any sub-band signal includes:

[0057]

[0058] Among them, kurtosis(X) represents the kurtosis operator corresponding to X; X is the sub-band signal obtained by wavelet packet decomposition of the broadband electric field signal or the output voltage signal of the ultra-high frequency sensor; x p and respectively represent the value and mean of the p-th sampling point, n is the total number of sampling points; μ and σ respectively represent the expectation and standard deviation of X.

[0059] Considering that the characteristic of the pulse signal is that it has a relatively steep rising edge, therefore, in the sub-band signal obtained by wavelet packet decomposition, it can be determined whether it is a valid signal through the kurtosis operator value of each sub-band signal. If it is an invalid signal, it means it is noise and needs to be removed; if it is a valid signal, it is retained. Among them, when removing noise, the sub-band signal with a kurtosis value less than the preset kurtosis operator threshold is determined as noise and removed.

[0060] Among them, the calculation formula of the kurtosis operator is as follows:

[0061]

[0062] Among them, kurtosis(X) represents the kurtosis operator corresponding to X; X is the sub-band signal obtained by wavelet packet decomposition of the broadband electric field signal or the output voltage signal of the ultra-high frequency sensor; x p and respectively represent the value and mean of the p-th sampling point, n is the total number of sampling points; μ and σ respectively represent the expectation and standard deviation of X.

[0063] In step 103, calculate the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-band according to the remaining first sub-band signal and second sub-band signal.

[0064] Preferably, the calculating the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-band according to the remaining first sub-band signal and second sub-band signal includes:

[0065]

[0066] τeff,i = |t e(t),i -t u(t),i |,

[0067] where |H eff,i | is the amplitude flatness corresponding to the transfer function in the i-th effective sub-band; |e max,i (t)| is the modulus maximum value of the i-th first sub-band signal corresponding to the broadband electric field signal; |u max,i (t)| is the modulus maximum value of the i-th second sub-band signal corresponding to the output voltage signal of the UHF sensor; τ eff,i is the group delay flatness corresponding to the transfer function in the i-th effective sub-band; t e(t),i is the pulse start point time of the i-th first sub-band signal corresponding to the broadband electric field signal; t u(t),i is the pulse start point time of the i-th second sub-band signal corresponding to the output voltage signal of the UHF sensor.

[0068] The process of the UHF sensor receiving signals can be expressed by the following formula:

[0069]

[0070] where θ, are respectively the azimuth angle and elevation angle of a certain point in space relative to the UHF sensor, and ω is the angular frequency of the electromagnetic wave propagating in space. is the frequency domain form of the pulsed electric field signal, H(ω) is the frequency domain effective height of the sensor, is the direction function of the UHF sensor.

[0071] The above formula can also be expressed as:

[0072]

[0073] where, is the transfer function of the UHF sensor, and it can be seen that it is related to the amplitude-frequency response, phase-frequency response and sensor angle.

[0074] The complex number H rec (ω) can also be written in the following form:

[0075]

[0076] In the formula, represents the amplitude-frequency gain of the sensor, is the phase angle of the sensor. In addition, the group delay flatness is defined as the opposite of the derivative of

[0077]

[0078] The physical meaning of group delay is the time difference for different frequency components in a broadband signal to reach a certain point in space. In a broadband antenna, it is expressed as the dispersion of electromagnetic waves with different frequencies in a certain direction of the antenna. When only considering the main direction, the inverse Fourier transform of Equation (3) gives:

[0079]

[0080] In the formula, θ m , respectively represent the main directions of θ, .

[0081] It can be easily seen from the above formula that for u m (t) to be distortionless relative to e m (t), should be a constant, and should be a linear function of ω.

[0082] When the amplitude flatness of the transfer function is constant within the passband , it corresponds to the ultra-high frequency sensor having a constant gain within its frequency band, that is, there is no spatial dispersion; when is linearly varying within the covered frequency band, corresponding to the group delay τ GD being a constant, that is, there is no frequency dispersion, and the signal received by the antenna is undistorted at this time. Therefore, the factors causing the distortion of the signal received by the ultra-high frequency sensor are: the amplitude flatness of the transfer function and the group delay flatness.

[0083] Therefore, in the embodiment of the present invention, the discrimination of the linear relationship is based on the amplitude flatness and the group delay flatness.

[0084] Specifically, first calculate the amplitude flatness of the transfer function within each effective sub-band, including:

[0085]

[0086] Then calculate the group delay flatness within each effective sub-band:

[0087] τ eff,i =|t e(t),i -t u(t),i |,

[0088] where, |H eff,i | is the amplitude flatness corresponding to the transfer function in the i-th effective sub-band; |e max,i (t)| is the maximum modulus of the i-th first sub-band signal corresponding to the broadband electric field signal; |u max,i (t)| is the maximum modulus of the i-th second sub-band signal corresponding to the output voltage signal of the ultra-high frequency sensor; τ eff,iis the group delay flatness corresponding to the transfer function within the i-th effective sub-band; t e(t),i is the pulse start time of the i-th first sub-band signal corresponding to the broadband electric field signal; t u(t),i is the pulse start time of the i-th second sub-band signal corresponding to the output voltage signal of the UHF sensor.

[0089] In the present invention, each wavelet packet corresponding to each frequency band corresponds to an amplitude flatness and a group delay flatness. For example, if there are 6 wavelet packets remaining after rejection, 6 amplitude flatnesses and 6 group delay flatnesses are calculated.

[0090] In step 104, according to the amplitude flatness and the group delay flatness corresponding to the transfer function within each effective sub-band, it is determined that the transfer function of the UHF sensor is a linear relationship.

[0091] Preferably, the determining that the transfer function of the UHF sensor is a linear relationship according to the amplitude flatness and the group delay flatness corresponding to the transfer function within each effective sub-band includes:

[0092] According to the amplitude flatness and the group delay flatness corresponding to the transfer function within each effective sub-band, calculate the variance of the amplitude flatness and the variance of the group delay flatness;

[0093] When the variance of the amplitude flatness is within a first preset range and the variance of the group delay flatness is within a second preset range, it is determined that the transfer function of the UHF sensor is a linear relationship, otherwise, it is determined that the transfer function of the UHF sensor is a non-linear relationship.

[0094] In an embodiment of the present invention, according to the amplitude flatness and the group delay flatness corresponding to each wavelet packet, calculate |H eff,i | and τ eff,i variance, when the variance of the amplitude flatness is within a first preset range and the variance of the group delay flatness is within a second preset range, it is determined that the transfer function of the UHF sensor is a linear relationship, otherwise, it is determined that the transfer function of the UHF sensor is a non-linear relationship.

[0095] The method of the present invention can denoise complex signals on site, remove noise components and obtain characteristic information. Aiming at the dispersion problem of UHF sensors for electromagnetic waves of different frequencies, key time-domain and frequency-domain information of UHF sensors is obtained, and by calculating the variance of the amplitude flatness and the group delay of the transfer function within the effective sub-band, the determination of whether the transfer function of the sensor is linear is realized.

[0096] Figure 3 is a schematic structural diagram of a linear relationship discrimination system 300 of a UHF partial discharge sensing system function according to an embodiment of the present invention. As Figure 3As shown, the linear relationship discrimination system 300 of the UHF partial discharge sensing system function provided by the embodiment of the present invention includes: a signal decomposition unit 301, a noise rejection unit 302, a calculation unit 303, and a linear relationship determination unit 304.

[0097] Preferably, the signal decomposition unit 301 is configured to decompose the broadband electric field signal and the UHF sensor output voltage signal into a plurality of first sub-band signals and a plurality of second sub-band signals with non-overlapping frequency bands respectively.

[0098] Preferably, the signal decomposition unit 301 decomposes the broadband electric field signal and the UHF sensor output voltage signal into a plurality of first sub-band signals and a plurality of second sub-band signals with non-overlapping frequency bands respectively based on wavelet packet decomposition.

[0099] Preferably, the noise rejection unit 302 is configured to perform noise judgment on each of the first sub-band signals and the second sub-band signals respectively, and reject the first sub-band signals and the second sub-band signals determined to be noise.

[0100] Preferably, the noise rejection unit 302 determines whether any first sub-band signal and second sub-band signal is noise by the following method, including:

[0101] Calculating the kurtosis operator value of any sub-band signal, and when the kurtosis operator value is less than a preset kurtosis operator threshold, determining that the any sub-band signal is noise;

[0102] Wherein, the kurtosis operator value of any sub-band signal is determined by the following method, including:

[0103]

[0104] Wherein, kurtosis(X) represents the kurtosis operator corresponding to X; X is the sub-band signal obtained by wavelet packet decomposition of the broadband electric field signal or the UHF sensor output voltage signal; x p and represent the value of the p-th sampling point and the mean value respectively, n is the total number of sampling points; μ and σ represent the expectation and standard deviation of X respectively.

[0105] Preferably, the calculation unit 303 is configured to calculate the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-frequency band according to the remaining first sub-band signals and second sub-band signals.

[0106] Preferably, the calculation unit 303 calculates the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-frequency band according to the remaining first sub-band signals and second sub-band signals, including:

[0107]

[0108] τ eff,i = |t e(t),i - t u(t),i |,

[0109] wherein, |H eff,i | is the amplitude flatness corresponding to the transfer function in the i-th effective sub-band; |e max,i (t)| is the modulus maximum value of the i-th first sub-band signal corresponding to the broadband electric field signal; |u max,i (t)| is the modulus maximum value of the i-th second sub-band signal corresponding to the output voltage signal of the UHF sensor; τ eff,i is the group delay flatness corresponding to the transfer function in the i-th effective sub-band; t e(t),i is the pulse start point time of the i-th first sub-band signal corresponding to the broadband electric field signal; t u(t),i is the pulse start point time of the i-th second sub-band signal corresponding to the output voltage signal of the UHF sensor.

[0110] Preferably, the linear relationship determination unit 304 is configured to determine that the transfer function of the UHF sensor is a linear relationship according to the amplitude flatness and the group delay flatness corresponding to the transfer function in each effective sub-band.

[0111] Preferably, the linear relationship determination unit 304 determines that the transfer function of the UHF sensor is a linear relationship according to the amplitude flatness and the group delay flatness corresponding to the transfer function in each effective sub-band, including:

[0112] Calculating the amplitude flatness variance and the group delay flatness variance according to the amplitude flatness and the group delay flatness corresponding to the transfer function in each effective sub-band;

[0113] When the amplitude flatness variance is within a first preset range and the group delay flatness variance is within a second preset range, it is determined that the transfer function of the UHF sensor is a linear relationship, otherwise, it is determined that the transfer function of the UHF sensor is a non-linear relationship.

[0114] The linear relationship discrimination system 300 of the UHF partial discharge sensing system function in the embodiment of the present invention corresponds to the linear relationship discrimination method 100 of the UHF partial discharge sensing system function in another embodiment of the present invention, and will not be elaborated here.

[0115] The present invention has been described by referring to a few embodiments. However, as is well known to those skilled in the art, as defined by the appended patent claims, other embodiments equivalent to those disclosed above of the present invention equally fall within the scope of the present invention.

[0116] Generally, all terms used in the claims are construed according to their ordinary meaning in the technical field to a person skilled in the art, unless otherwise expressly defined therein. All references to "a / the [device, component, etc.]" are to be construed openly as at least one instance of the device, component, etc., unless otherwise expressly stated. The steps of any method disclosed herein need not be performed in the exact order disclosed, unless expressly stated.

[0117] Those skilled in the art will appreciate that the embodiments of the present application may be provided as a method, a system, or a computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

[0118] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and combinations of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, such that the instructions executed by the processor of the computer or other programmable data processing device produce a means for realizing the functions specified in Figure 1 one or more of the flows Figure 1 or blocks.

[0119] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer-readable memory produce a manufacture including an instruction means that realizes the functions specified in Figure 1 one or more of the flows Figure 1 or blocks.

[0120] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are performed on the computer or other programmable device to produce a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for realizing the functions specified in Figure 1 one or more of the flows Figure 1 or blocks.

[0121] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: it is still possible to modify the specific implementation manners of the present invention or make equivalent replacements, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A method for discriminating the linear relationship of the function of a very high frequency partial discharge sensing system, characterized in that The method includes: Separately decomposing the broadband electric field signal and the output voltage signal of the UHF sensor into a plurality of first sub-band signals and a plurality of second sub-band signals with non-overlapping frequency bands; Separately performing noise judgment on each first sub-band signal and second sub-band signal, and removing the first sub-band signals and second sub-band signals determined to be noise; Calculating the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-frequency band according to the remaining first sub-band signals and second sub-band signals; Determining that the transfer function of the UHF sensor is a linear relationship according to the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-frequency band; Wherein, the method determines whether any first sub-band signal and second sub-band signal are noise by the following method, including: Calculating the kurtosis operator value of any sub-band signal, and determining that the any sub-band signal is noise when the kurtosis operator value is less than a preset kurtosis operator threshold; Wherein, the kurtosis operator value of any sub-band signal is determined by the following method, including: Among them, kurtosis(X) represents the kurtosis operator corresponding to X; X is the sub-band signal obtained after wavelet packet decomposition of the broadband electric field signal or the output voltage signal of the ultra-high frequency sensor; x p and respectively represent the value and mean of the p-th sampling point, and n is the total number of sampling points; μ and σ respectively represent the expectation and standard deviation of X; Wherein, calculating the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-frequency band according to the remaining first sub-band signals and second sub-band signals, including: τ eff,i = |t e(t),i - t u(t),i |, Among them, |H eff,i | is the amplitude flatness corresponding to the transfer function in the i-th effective sub-band; |e max,i (t)| is the modulus maximum value of the i-th first sub-band signal corresponding to the broadband electric field signal; |u max,i (t)| is the modulus maximum value of the i-th second sub-band signal corresponding to the output voltage signal of the UHF sensor; τ eff,i is the group delay flatness corresponding to the transfer function in the i-th effective sub-band; t e(t),i is the pulse starting point time of the i-th first sub-band signal corresponding to the broadband electric field signal; t u(t),i is the pulse starting point time of the i-th second sub-band signal corresponding to the output voltage signal of the UHF sensor.

2. The method according to claim 1, wherein The method respectively decomposes the broadband electric field signal and the output voltage signal of the UHF sensor into a plurality of first sub-band signals and a plurality of second sub-band signals with non-overlapping frequency bands based on wavelet packet decomposition.

3. The method according to claim 1, wherein Determining that the transfer function of the UHF sensor is a linear relationship according to the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-frequency band, including: Calculating the amplitude flatness variance and group delay flatness variance according to the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-frequency band; When the amplitude flatness variance is within a first preset range and the group delay flatness variance is within a second preset range, determining that the transfer function of the UHF sensor is a linear relationship, otherwise, determining that the transfer function of the UHF sensor is a non-linear relationship.

4. A discrimination system for the linear relationship of the function of a very high frequency partial discharge sensing system, characterized in that, The system includes: A signal decomposition unit for separately decomposing the broadband electric field signal and the output voltage signal of the UHF sensor into a plurality of first sub-band signals and a plurality of second sub-band signals with non-overlapping frequency bands; A noise removal unit for separately performing noise judgment on each first sub-band signal and second sub-band signal, and removing the first sub-band signals and second sub-band signals determined to be noise; A calculation unit for calculating the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-frequency band according to the remaining first sub-band signals and second sub-band signals; A linear relationship determination unit for determining that the transfer function of the UHF sensor is a linear relationship according to the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-frequency band; Wherein, the noise removal unit determines whether any first sub-band signal and second sub-band signal are noise by the following method, including: Calculating the kurtosis operator value of any sub-band signal, and determining that the any sub-band signal is noise when the kurtosis operator value is less than a preset kurtosis operator threshold; Wherein, the kurtosis operator value of any sub-band signal is determined by the following method, including: Among them, kurtosis(X) represents the kurtosis operator corresponding to X; X is the sub-band signal obtained after wavelet packet decomposition of the broadband electric field signal or the output voltage signal of the ultra-high frequency sensor; x p and respectively represent the value and the mean value of the p-th sampling point, and n is the total number of sampling points; μ and σ respectively represent the expectation and the standard deviation of X; Among them, the calculation unit calculates the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-band according to the remaining first sub-band signal and second sub-band signal, including: τ eff,i = |t e(t),i - t u(t),i |, where, |H eff,i | is the amplitude flatness corresponding to the transfer function in the i-th effective sub-band; |e max,i (t)| is the modulus maximum value of the i-th first sub-band signal corresponding to the broadband electric field signal; |u max,i (t)| is the modulus maximum value of the i-th second sub-band signal corresponding to the output voltage signal of the UHF sensor; τ eff,i is the group delay flatness corresponding to the transfer function in the i-th effective sub-band; t e(t),i is the pulse starting point time of the i-th first sub-band signal corresponding to the broadband electric field signal; t u(t),i is the pulse starting point time of the i-th second sub-band signal corresponding to the output voltage signal of the UHF sensor.

5. The system according to claim 4, wherein The signal decomposition unit respectively decomposes the broadband electric field signal and the output voltage signal of the UHF sensor into a plurality of first sub-band signals and a plurality of second sub-band signals with non-overlapping frequency bands based on wavelet packet decomposition.

6. The system according to claim 4, wherein The linear relationship determination unit determines that the transfer function of the UHF sensor is a linear relationship according to the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-band, including: Calculating the variance of amplitude flatness and the variance of group delay flatness according to the amplitude flatness and group delay flatness corresponding to the transfer function in each effective sub-band; When the variance of amplitude flatness is within a first preset range and the variance of group delay flatness is within a second preset range, it is determined that the transfer function of the UHF sensor is a linear relationship, otherwise, it is determined that the transfer function of the UHF sensor is a non-linear relationship.

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