An anti-interference method, device and medium in transformer partial discharge detection

Abstract

The application discloses an anti-interference method and device in transformer partial discharge detection and a medium, and is applied to the technical field of transformer detection, and is used for solving the problem that the existing anti-interference technology influences the completeness and accuracy of a partial discharge signal. The method comprises the following steps: collecting pulsation noise of a to-be-detected converter transformer at a preset position when the to-be-detected converter transformer is in a power-off static state, so as to determine a characteristic frequency spectrum of the pulsation noise in the to-be-detected converter transformer; detecting a partial discharge signal of the to-be-detected converter transformer at the preset position when the to-be-detected converter transformer is in a running state, and acquiring a frequency spectrum of the partial discharge signal; acquiring the partial discharge signal in a preset frequency range as a to-be-de-noised partial discharge signal; and removing a signal of a preset proportion in the to-be-de-noised partial discharge signal, so as to filter the pulsation noise in the preset frequency range and obtain a de-noised signal of the to-be-de-noised partial discharge signal.

Description

Technical Field

[0001] This invention relates to the field of transformer testing technology, and in particular to an anti-interference method, equipment and medium for partial discharge detection in transformers. Background Technology

[0002] The construction of DC transmission networks relies heavily on DC electrical equipment. As the most critical component in ultra-high voltage (UHVDC) transmission systems, the condition of the converter transformer directly impacts the safe operation of the entire UHVDC transmission project. Based on extensive data analysis, the insulation condition of the converter transformer is a major factor affecting its operational status, and partial discharge-induced aging and deterioration of insulation materials is a significant cause of converter transformer failures. Therefore, partial discharge detection of converter transformers is crucial for ensuring their safe operation. The valve-side winding of the converter transformer connects to the valve assembly used for commutation. The periodic switching process of the valve assembly causes charging and discharging of its internal capacitance and inductance, resulting in periodic pulsating interference that severely affects the accuracy of partial discharge detection. Therefore, an interference-resistant environment is a crucial aspect of partial discharge detection.

[0003] Existing technologies for noise suppression in partial discharge detection include wavelet decomposition and singular value decomposition. However, wavelet decomposition faces several challenges, such as difficulty in selecting the wavelet fundamental, the number of decomposition layers, and determining the threshold. Singular value decomposition, on the other hand, suffers from difficulties in determining the singular value threshold and high computational complexity. Furthermore, existing technologies typically use high-pass filtering to remove pulsation interference, but this method removes low-frequency components from the partial discharge signal, compromising its integrity and thus affecting the accuracy of partial discharge detection. Summary of the Invention

[0004] This invention provides an anti-interference method, device, and medium for partial discharge detection in transformers, which addresses the problem that existing anti-interference technologies affect the integrity and accuracy of partial discharge signals.

[0005] Therefore, one technical solution adopted by the present invention is: an anti-interference method for partial discharge detection in transformers, comprising:

[0006] When the converter transformer under test is in a de-energized and stationary state, the pulsating noise of the converter transformer under test at a preset position is collected, so as to determine the characteristic spectrum of the pulsating noise in the converter transformer under test based on the pulsating noise;

[0007] When the converter transformer under test is in operation, the partial discharge signal of the converter transformer under test at a preset position is detected, and the spectrum of the partial discharge signal is obtained;

[0008] The partial discharge signal within a preset frequency range is acquired as the partial discharge signal to be denoised;

[0009] The signal corresponding to the characteristic spectrum of the pulsating noise in the partial discharge signal to be denoised is removed by a preset ratio to filter the pulsating noise within the preset frequency range, thereby obtaining the denoised signal of the partial discharge signal to be denoised; wherein, the preset ratio is used to represent the denoising intensity factor of the partial discharge signal to be denoised.

[0010] Furthermore, the step of collecting the pulsating noise of the converter transformer under test at a preset position when the transformer is in a de-energized and stationary state, and determining the characteristic spectrum of the pulsating noise in the converter transformer under test based on the pulsating noise, specifically includes:

[0011] When the converter transformer under test is in a de-energized and static state, the pulsating noise of the converter transformer under test at preset positions on both sides of the grid-side winding is collected; wherein, the preset positions include: the high-voltage bushing end screen and the neutral point grounding point located on both sides of the grid-side winding of the converter transformer under test;

[0012] The pulsating noise is converted based on Fourier transform to obtain the pulsating noise spectrum corresponding to the pulsating noise;

[0013] The average noise spectrum value at each frequency point in the pulsating noise spectrum is used as the characteristic spectrum of the pulsating noise in the converter transformer under test.

[0014] Furthermore, the step of detecting the partial discharge signal of the converter transformer under test at a preset position when the transformer under test is in operation, and acquiring the spectrum of the partial discharge signal, specifically includes:

[0015] When the converter transformer under test is in operation, a partial discharge detection device is used to perform partial discharge detection on the converter transformer under test at a preset position to obtain the partial discharge signal containing noise signal.

[0016] The partial discharge signal is subjected to Fourier transform based on the Fourier transform formula to obtain the spectrum of the partial discharge signal.

[0017] Further, the signal corresponding to the characteristic spectrum of the pulsating noise in the partial discharge signal to be denoised is removed by a preset ratio to filter the pulsating noise within the preset frequency range, thereby obtaining the denoised signal of the partial discharge signal to be denoised. Specifically, this includes:

[0018] Based on a preset denoising formula, the signal corresponding to the characteristic spectrum of the pulsating noise in the partial discharge signal to be denoised is removed by a preset ratio to obtain the denoised signal of the partial discharge signal to be denoised; wherein, the preset denoising formula is:

[0019]

[0020] Among them, X 400k '(ω i X represents the denoised signal at 400kHz. 400k (ω i X(ωi) represents the partial discharge signal to be denoised at 400kHz, K represents the preset ratio, ωi represents each frequency point within the preset range, and X(ωi) represents the frequency point within the preset range. i P(ω) represents the partial discharge signal to be denoised. i ) represents the characteristic spectrum of pulsating noise, Re[X(ω) i Im[X(ω)] represents the real part of the spectrum corresponding to the denoised signal. i )] represents the imaginary part of the spectrum corresponding to the denoised signal.

[0021] Further, after removing the signal corresponding to the characteristic spectrum of the pulsating noise in the partial discharge signal to be denoised by a preset ratio to filter the pulsating noise within the preset frequency range and obtain the denoised signal of the partial discharge signal to be denoised, the method further includes:

[0022] The characteristic spectrum value of the pulsating noise corresponding to each frequency point within the preset frequency range, the spectrum value corresponding to the denoised signal of the partial discharge signal to be denoised, and the denoising intensity factor corresponding to the denoised signal are input into the preset correlation coefficient formula to output the corresponding correlation coefficient.

[0023] Adjust the denoising intensity factor in the preset correlation coefficient formula, and input the denoised signal of the partial discharge signal to be denoised corresponding to the adjusted denoising factor, as well as the characteristic spectrum value of the pulsating noise corresponding to each frequency point in the preset frequency range, into the preset correlation coefficient formula to obtain the adjusted correlation coefficient.

[0024] Among the corresponding correlation coefficients and the adjusted correlation coefficients, the correlation coefficient with the smallest absolute value is obtained.

[0025] The denoising intensity factor corresponding to the correlation coefficient with the smallest absolute value is taken as the optimal denoising intensity factor of the partial discharge signal to be denoised, and the partial discharge signal to be denoised is denoised based on the optimal denoising intensity factor.

[0026] Furthermore, before inputting the characteristic spectrum values ​​of the pulsating noise corresponding to each frequency point within the preset frequency range, the spectrum value corresponding to the denoised signal of the partial discharge signal to be denoised, and the denoising intensity factor corresponding to the denoised signal into the preset correlation coefficient formula, the method further includes:

[0027] Based on the characteristic spectral values ​​of the pulsating noise at each frequency point within the preset frequency range and the spectral values ​​of the denoised signal, the similarity between the pulsating noise signal and the denoised signal within the preset frequency range is obtained, and the formula corresponding to the similarity is used as the preset correlation coefficient formula; wherein, the preset correlation coefficient formula is:

[0028]

[0029] Where r represents the correlation coefficient, X'(ω) i ) represents the denoised signal.

[0030] Furthermore, the denoising of the partial discharge signal to be denoised based on the optimal denoising intensity factor specifically includes:

[0031] Based on the optimal denoising intensity factor, the optimal proportion of the partial discharge signal to be denoised is determined;

[0032] The signals corresponding to the optimal ratio, the partial discharge signal to be denoised, and the characteristic spectrum of the pulsating noise are input into the preset denoising formula;

[0033] Based on the preset denoising formula, the optimal proportion of the signal corresponding to the characteristic spectrum of the pulsating noise in the partial discharge signal to be denoised is removed to obtain the denoised partial discharge signal of the converter transformer.

[0034] Further, after removing the signal corresponding to the characteristic spectrum of the pulsating noise in the partial discharge signal to be denoised by a preset ratio to filter the pulsating noise within the preset frequency range, the method further includes:

[0035] After filtering the pulsating noise within the preset frequency range, an inverse Fourier transform is performed on the spectrum corresponding to the partial discharge signal to be denoised, to obtain the denoised signal of the partial discharge signal to be denoised corresponding to the converter transformer.

[0036] Another technical solution adopted in this invention is: an anti-interference device for partial discharge detection in transformers, the device comprising:

[0037] At least one processor; and,

[0038] A memory communicatively connected to the at least one processor; wherein,

[0039] The memory stores instructions executable by the at least one processor, which, when executed by the at least one processor, enable the at least one processor to:

[0040] When the converter transformer under test is in a de-energized and stationary state, the pulsating noise of the converter transformer under test at a preset position is collected, so as to determine the characteristic spectrum of the pulsating noise in the converter transformer under test based on the pulsating noise;

[0041] When the converter transformer under test is in operation, the partial discharge signal of the converter transformer under test at a preset position is detected, and the spectrum of the partial discharge signal is obtained;

[0042] The partial discharge signal within a preset frequency range is acquired as the partial discharge signal to be denoised;

[0043] The signal corresponding to the characteristic spectrum of the pulsating noise in the partial discharge signal to be denoised is removed by a preset ratio to filter the pulsating noise within the preset frequency range, thereby obtaining the denoised signal of the partial discharge signal to be denoised; wherein, the preset ratio is used to represent the denoising intensity factor of the partial discharge signal to be denoised.

[0044] Another technical solution adopted by the present invention is: a non-volatile computer storage medium storing computer-executable instructions, wherein the computer-executable instructions are configured as follows:

[0045] When the converter transformer under test is in a de-energized and stationary state, the pulsating noise of the converter transformer under test at a preset position is collected, so as to determine the characteristic spectrum of the pulsating noise in the converter transformer under test based on the pulsating noise;

[0046] When the converter transformer under test is in operation, the partial discharge signal of the converter transformer under test at a preset position is detected, and the spectrum of the partial discharge signal is obtained;

[0047] The partial discharge signal within a preset frequency range is acquired as the partial discharge signal to be denoised;

[0048] The signal corresponding to the characteristic spectrum of the pulsating noise in the partial discharge signal to be denoised is removed by a preset ratio to filter the pulsating noise within the preset frequency range, thereby obtaining the denoised signal of the partial discharge signal to be denoised; wherein, the preset ratio is used to represent the denoising intensity factor of the partial discharge signal to be denoised.

[0049] The above-mentioned at least one technical solution adopted in this invention can achieve the following beneficial effects:

[0050] By collecting pulsating noise data from the converter transformer under test during a power outage and static state, the characteristic spectrum of the pulsating noise was determined. Then, by performing partial discharge detection on the converter transformer under test during operation, a partial discharge signal containing pulsating noise was obtained, and its spectrum was acquired. This allows for the removal of the signal corresponding to the characteristic spectrum of the pulsating noise from the partial discharge signal within a preset frequency range at a preset ratio. This achieves pulsating noise removal within the preset frequency range. Furthermore, because noise removal is performed at a preset ratio, the low-frequency components in the partial discharge signal are preserved, avoiding the problem of low-frequency components being filtered out by overall low-frequency removal, thus improving the accuracy of partial discharge detection. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0052] Figure 1 This is a schematic flowchart of an anti-interference method for partial discharge detection in a transformer, provided by an embodiment of the present invention.

[0053] Figure 2 This is a schematic diagram of the internal structure of an anti-interference device for transformer partial discharge detection provided in an embodiment of the present invention;

[0054] Figure 3 This is a schematic diagram of the internal structure of a non-volatile storage medium provided in an embodiment of the present invention. Detailed Implementation

[0055] Converter transformers play a pivotal role in converter substations and are crucial electrical equipment in power system transmission and transformation operations, as well as in ultra-high voltage direct current (UHVDC) transmission systems. A failure in a converter transformer can lead to the shutdown of part or all of the system, potentially causing a serious power outage. Insulation failure in internal connectors, valve-side windings, and outgoing bushings is a significant cause of insulation failure in converter transformers. Partial discharge faults are a major manifestation of aging and deterioration of insulation materials. Therefore, online monitoring of partial discharge in converter transformers is essential for the timely detection of early potential faults, which is crucial for the safety of both the converter transformer and the UHVDC transmission system. However, because the valve-side windings of the converter transformer connect to valve assemblies used for switching, the periodic switching process of these assemblies causes charging and discharging of their internal capacitance and inductance, resulting in periodic pulsating interference that severely affects the accuracy of partial discharge detection. Therefore, researching partial discharge pulsation suppression technology for converter transformers is of great importance for improving the accuracy of partial discharge detection.

[0056] Currently, common noise suppression techniques for partial discharge detection mainly include wavelet decomposition and singular value decomposition (SVD). Wavelet decomposition faces several challenges in application, such as difficulty in selecting the wavelet fundamental, the number of decomposition layers, and determining the threshold. Singular value decomposition, on the other hand, faces difficulties in determining the singular value threshold and incurring high computational costs. Furthermore, since the main components of pulsation interference are concentrated in the low-frequency band, high-pass filtering can remove pulsation interference, but it also filters out the low-frequency components of the partial discharge signal, disrupting the integrity of the partial discharge signal and thus affecting the accuracy of partial discharge detection.

[0057] This embodiment provides an anti-interference method, device, and medium for partial discharge detection in transformers. By subtracting a certain proportion of the signal component corresponding to the characteristic spectrum of pulsating noise from the spectrum of the partial discharge signal to be denoised, until the absolute value of the correlation coefficient between the denoised signal spectrum and the characteristic spectrum is minimized, the pulsating noise in the partial discharge signal is effectively removed while retaining the partial discharge signal component in the low-frequency band, thus avoiding the problem of the partial discharge signal integrity being compromised. Furthermore, effective noise removal is achieved based on Fourier transform, a preset denoising formula, and a preset correlation coefficient formula, avoiding the complexity of traditional wavelet decomposition and singular value decomposition processes.

[0058] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0059] as follows Figure 1 As shown, this invention provides a schematic flowchart of an anti-interference method for partial discharge detection in transformers, in one or more embodiments. Figure 1 It can be seen that the method includes the following steps:

[0060] S101: Collect the pulsating noise of the converter transformer under test at a preset position when the converter transformer under test is in a de-energized and static state, so as to determine the characteristic spectrum of the pulsating noise in the converter transformer under test based on the pulsating noise.

[0061] To obtain the characteristics of noise in the converter transformer under test and thus effectively suppress noise interference in partial discharge detection, in one or more embodiments of the present invention, the pulsating noise at a preset location of the converter transformer under test is first collected when the transformer is in a de-energized and stationary state. The characteristic spectrum of the pulsating noise in the converter transformer under test is then determined based on the collected pulsating noise analysis, facilitating subsequent anti-interference processes based on the characteristic spectrum of the pulsating noise and effectively obtaining the noise characteristics.

[0062] Specifically, in one or more embodiments of the present invention, the pulsating noise of the converter transformer under test at a preset position is collected when the converter transformer under test is in a de-energized and static state, so as to determine the characteristic spectrum of the pulsating noise in the converter transformer under test based on the pulsating noise, specifically including the following steps:

[0063] First, when the converter transformer under test is in a de-energized and static state, the pulsating noise at preset positions on both sides of the grid-side winding of the converter transformer under test is collected. It should be noted that common partial discharge sensors generally include: bushing end-screen sensors installed at the bushing end screen, and high-frequency sensors used to sense pulse current signals on the grounding wire when partial discharge occurs in power equipment such as transformers. Furthermore, since the pulsating interference is caused by the valve assembly connected to the valve-side winding of the converter transformer for commutation, the periodic on-off process of the valve assembly causes the charging and discharging of its internal capacitance and inductance, resulting in periodic pulsating interference. Therefore, to improve the accuracy of partial discharge detection, the corresponding positions for monitoring partial discharge with pulsating interference are set as preset positions. Specifically, the preset positions include: the high-voltage bushing end screen and the neutral grounding point on both sides of the grid-side winding of the converter transformer under test. Then, after collecting the pulsating noise, it is converted based on Fourier transform to obtain the corresponding pulsating noise spectrum. The average noise spectrum value at each frequency point in the obtained pulsating noise spectrum, i.e., the average value of the pulsating noise spectrum at both ends of the winding, is used as the characteristic spectrum of the pulsating noise in the converter transformer under test. This completes the acquisition of the characteristic spectrum of the pulse noise of the converter transformer under test in the power-off state. By collecting pulsating noise at the corresponding location of partial discharge detection, the targeting of subsequent partial discharge signal filtering is improved, which is beneficial to improving the accuracy of partial discharge detection.

[0064] S102: When the converter transformer under test is in operation, detect the partial discharge signal of the converter transformer under test at a preset position, and obtain the spectrum of the partial discharge signal.

[0065] To prevent insulation material aging caused by partial discharge faults, which could lead to malfunctions in the converter transformer under test, this invention detects partial discharge signals at preset locations while the converter transformer is in operation. The spectrum of these partial discharge signals is then obtained, and anti-interference analysis is performed based on this spectrum. This achieves complete and accurate detection of the partial discharge signals, thereby ensuring the safety of the converter transformer under test.

[0066] Specifically, in one or more embodiments of the present invention, detecting the partial discharge signal of the converter transformer under test at a preset position when the transformer under test is in operation, and obtaining the spectrum of the partial discharge signal, specifically includes the following process: First, when the converter transformer under test is in operation, partial discharge detection is performed at the preset position using a partial discharge detection device to obtain the partial discharge signal containing noise. It should be noted that the partial discharge detection device can be a bushing end-screen sensor, a high-frequency sensor, an ultra-high-frequency sensor, an ultrasonic sensor, etc. After obtaining the noise-infused partial discharge signal, a Fourier transform is performed on the partial discharge signal using the Fourier transform formula to obtain the spectrum of the partial discharge signal containing noise.

[0067] It should be noted that the Fourier formula is as follows:

[0068] X(ω)=F(x(t))=Re[X(ω)]+iIm[X(ω)];

[0069] X(ω) is the spectrum of the partial discharge signal, x(t) is the partial discharge signal, F(x(t)) represents the Fourier transform of x(t), Re[X(ω)] represents the real part of X(ω), and Im[X(ω)] represents the imaginary part of X(ω).

[0070] By converting the partial discharge signal to the frequency domain using Fourier transform, and then analyzing it based on the obtained spectrum and the frequency domain characteristics of the signal, this method avoids several problems faced by wavelet decomposition methods, such as difficulty in selecting the wavelet fundamental wave and the number of decomposition layers, and difficulty in determining the threshold. It also avoids several problems faced by singular value decomposition methods, such as difficulty in determining the singular value threshold and large computational load. This simplifies the processing of transformer partial discharge detection in the anti-interference process and improves the efficiency of the anti-interference process.

[0071] S103: Acquire the partial discharge signal within a preset frequency range as the partial discharge signal to be denoised.

[0072] Since the main components of pulsating interference are concentrated in the low-frequency band, the concentration range of the pulsating noise can be determined based on the characteristic spectrum of the pulsating noise obtained in step S101 above. This determined concentration range is then used as a preset range, and the partial discharge signals within this preset frequency range are selected as the partial discharge signals to be denoised. In this specification, for a certain application scenario, a frequency band below 400kHz is selected as the preset frequency range. Therefore, the partial discharge signals below 400kHz are the partial discharge signals to be denoised.

[0073] S104: Remove the signal corresponding to the characteristic spectrum of the pulsating noise in the partial discharge signal to be denoised by a preset ratio to filter the pulsating noise within the preset frequency range and obtain the denoised signal of the partial discharge signal to be denoised; wherein, the preset ratio is used to represent the denoising intensity factor of the partial discharge signal to be denoised.

[0074] Since the partial discharge signal to be denoised contains pulsating noise interference, to avoid the problem that conventional techniques, such as high-pass filtering, can remove pulsating interference but also filter out low-frequency components of the partial discharge signal, thus compromising the integrity of the partial discharge signal, this embodiment of the invention removes the signal corresponding to the characteristic spectrum of pulsating noise in the partial discharge signal to be denoised by a preset ratio, thereby filtering out pulsating noise within a preset frequency range and obtaining a denoised signal of the partial discharge signal to be denoised. It should be noted that the preset ratio represents the denoising intensity factor of the partial discharge signal to be denoised.

[0075] In one or more embodiments of the present invention, the signal corresponding to the characteristic spectrum of the pulsating noise in the partial discharge signal to be denoised is removed by a preset ratio to filter the pulsating noise within the preset frequency range, thereby obtaining a denoised signal of the partial discharge signal to be denoised, specifically including:

[0076] According to a pre-set denoising formula, the signal corresponding to the characteristic spectrum of pulsating noise in the partial discharge signal to be denoised is removed according to a preset ratio, thereby obtaining the denoised signal of the partial discharge signal to be denoised. It should be noted that the preset denoising formula is as follows:

[0077]

[0078] Among them, X 400k '(ω i X represents the denoised signal at 400kHz. 400k (ω i X(ωi) represents the partial discharge signal to be denoised at 400kHz, K represents the preset ratio, ωi represents each frequency point within the preset range, and X(ωi) represents the frequency point within the preset range. i P(ω) represents the partial discharge signal to be denoised. i ) represents the characteristic spectrum of pulsating noise, Re[X(ω) i Im[X(ω)] represents the real part of the spectrum corresponding to the denoised signal. i )] represents the imaginary part of the spectrum corresponding to the denoised signal.

[0079] For the preset ratio K representing the denoising intensity factor, the larger K is, the more pulsating noise is subtracted, and the more equivalent spectral components of pulsating noise are filtered out in the partial discharge signal to be denoised.

[0080] Further, after removing the signal corresponding to the characteristic spectrum of the pulsating noise in the partial discharge signal to be denoised by a preset ratio to filter the pulsating noise within a preset frequency range and obtain the denoised signal of the partial discharge signal to be denoised, the method further includes the following steps: First, input the characteristic spectrum value of the pulsating noise corresponding to each frequency point within the preset frequency range, the spectrum value corresponding to the denoised signal of the partial discharge signal to be denoised, and the denoising intensity factor corresponding to the denoised signal into a preset correlation coefficient formula to obtain the corresponding correlation coefficient. In one or more embodiments of the present invention, before inputting the characteristic spectrum value of the pulsating noise corresponding to each frequency point within the preset frequency range, the spectrum value corresponding to the denoised signal of the partial discharge signal to be denoised, and the denoising intensity factor corresponding to the denoised signal into the preset correlation coefficient formula, the method further includes the following process: Based on the characteristic spectrum value of the pulsating noise corresponding to each frequency point within the preset frequency range and the spectrum value of the denoised signal, obtain the similarity between the pulsating noise signal and the denoised signal within the preset frequency range, and use the formula corresponding to the similarity as the preset correlation coefficient formula; wherein, the preset correlation coefficient formula is:

[0081]

[0082] Where r represents the correlation coefficient, X'(ω) i ) represents the denoised signal.

[0083] It is understandable that the lower the similarity between the pulsating noise signal and the denoised signal within the preset range, the better the denoising effect.

[0084] After obtaining the preset correlation coefficient formula based on the above steps, the denoising intensity factor (i.e., the preset ratio) within the preset correlation coefficient formula is adjusted. The denoised partial discharge signal corresponding to the adjusted denoising factor, along with the characteristic spectral values ​​of the pulsating noise at each frequency point within the preset frequency range, are input into the preset correlation coefficient formula to obtain the adjusted correlation coefficient. Among the obtained correlation coefficients and adjusted correlation coefficients, the correlation coefficient with the smallest absolute value is selected. Then, the denoising intensity factor corresponding to the correlation coefficient with the smallest absolute value is taken as the optimal denoising intensity factor for the partial discharge signal to be denoised, and denoising of the partial discharge signal is performed based on the optimal denoising intensity factor. The aforementioned preset correlation coefficient formula can be determined based on the similarity between the pulsating noise signal and the denoised signal within a preset range. Therefore, by randomly selecting the denoising intensity, i.e., the preset ratio k, different correlation coefficients are obtained. When the absolute value of the spectral correlation coefficient is the smallest, it means that the noise signal component corresponding to the characteristic spectrum of the pulsating noise in the spectrum of the denoised signal has been reduced to the minimum value, achieving the best denoising effect. Then, the denoising intensity factor corresponding to the correlation coefficient with the smallest absolute value among all correlation coefficients is the optimal preset ratio, which can effectively remove pulsating noise while retaining the partial discharge signal component within the preset frequency range, ensuring the integrity of the partial discharge signal component.

[0085] Furthermore, in one or more embodiments of the present invention, denoising the partial discharge signal to be denoised based on the optimal denoising intensity factor specifically includes the following process: First, as can be seen from the above process, the denoising intensity factor corresponds to a preset ratio. Therefore, after determining the optimal denoising intensity factor, the optimal ratio k of the partial discharge signal to be denoised can be determined based on the optimal denoising intensity factor. Then, the determined optimal ratio, the partial discharge signal to be denoised, and the signal corresponding to the characteristic spectrum of the pulsating noise are input into a preset denoising formula. According to the preset denoising formula, the signal corresponding to the characteristic spectrum of the pulsating noise in the partial discharge signal to be denoised at the optimal ratio is removed to obtain the denoised partial discharge signal of the converter transformer.

[0086] Furthermore, in one or more embodiments of the present invention, after removing the signal corresponding to the characteristic spectrum of pulsating noise in the partial discharge signal to be denoised by a preset ratio and filtering the pulsating noise within a preset frequency range, the method further includes the following steps: As can be seen from the above steps S101 and S102, in order to facilitate the analysis of the characteristics of pulsating noise and the denoising of the partial discharge signal, the partial discharge signal is transformed to the frequency domain for analysis based on Fourier transform. Therefore, after removing the pulsating noise contained in the partial discharge signal based on the above process, it is also necessary to perform an inverse Fourier transform on the spectrum corresponding to the partial discharge signal to be denoised after filtering the pulsating noise within the preset frequency range, thereby obtaining the denoised signal of the partial discharge signal to be denoised corresponding to the converter transformer.

[0087] like Figure 2 As shown, one or more embodiments of the present invention provide a schematic diagram of the internal structure of an anti-interference device for transformer partial discharge detection.

[0088] Depend on Figure 2 It is understood that, in one or more embodiments of the present invention, an anti-interference device for transformer partial discharge detection includes:

[0089] At least one processor 201; and,

[0090] The memory 202 is communicatively connected to the at least one processor 201; wherein,

[0091] The memory 202 stores instructions that can be executed by the at least one processor 201, the instructions being executed by the at least one processor 201 to enable the at least one processor 201 to:

[0092] When the converter transformer under test is in a de-energized and stationary state, the pulsating noise of the converter transformer under test at a preset position is collected, so as to determine the characteristic spectrum of the pulsating noise in the converter transformer under test based on the pulsating noise;

[0093] When the converter transformer under test is in operation, the partial discharge signal of the converter transformer under test at a preset position is detected, and the spectrum of the partial discharge signal is obtained;

[0094] The partial discharge signal within a preset frequency range is acquired as the partial discharge signal to be denoised;

[0095] The signal corresponding to the characteristic spectrum of the pulsating noise in the partial discharge signal to be denoised is removed by a preset ratio to filter the pulsating noise within the preset frequency range, thereby obtaining the denoised signal of the partial discharge signal to be denoised; wherein, the preset ratio is used to represent the denoising intensity factor of the partial discharge signal to be denoised.

[0096] like Figure 3 As shown, one or more embodiments of the present invention provide a schematic diagram of the internal structure of a non-volatile storage medium.

[0097] Depend on Figure 3 It is understood that, in one or more embodiments of the present invention, a non-volatile storage medium stores computer-executable instructions 301, which include:

[0098] When the converter transformer under test is in a de-energized and stationary state, the pulsating noise of the converter transformer under test at a preset position is collected, so as to determine the characteristic spectrum of the pulsating noise in the converter transformer under test based on the pulsating noise;

[0099] When the converter transformer under test is in operation, the partial discharge signal of the converter transformer under test at a preset position is detected, and the spectrum of the partial discharge signal is obtained;

[0100] The partial discharge signal within a preset frequency range is acquired as the partial discharge signal to be denoised;

[0101] The signal corresponding to the characteristic spectrum of the pulsating noise in the partial discharge signal to be denoised is removed by a preset ratio to filter the pulsating noise within the preset frequency range, thereby obtaining the denoised signal of the partial discharge signal to be denoised; wherein, the preset ratio is used to represent the denoising intensity factor of the partial discharge signal to be denoised.

[0102] The various embodiments in this invention are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the embodiments of apparatus, devices, and non-volatile computer storage media are basically similar to the method embodiments, so the descriptions are relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0103] The foregoing has described specific embodiments of the invention. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired results. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0104] The above description is merely one or more embodiments of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to one or more embodiments of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of one or more embodiments of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for anti-interference in transformer partial discharge detection, characterized in that, The method comprises the following steps: acquiring pulsation noise of a to-be-detected converter transformer at a preset position when the to-be-detected converter transformer is in a power-off static state, and determining a characteristic frequency spectrum of the pulsation noise in the to-be-detected converter transformer based on the pulsation noise; detecting a partial discharge signal of the to-be-detected converter transformer at the preset position when the to-be-detected converter transformer is in a running state, and acquiring a frequency spectrum of the partial discharge signal; acquiring the partial discharge signal in a preset frequency range as a to-be-de-noised partial discharge signal; removing, by a preset proportion, a signal corresponding to the characteristic frequency spectrum of the pulsation noise in the to-be-de-noised partial discharge signal, filtering the pulsation noise in the preset frequency range, and obtaining a de-noised signal of the to-be-de-noised partial discharge signal; wherein the preset proportion represents a de-noising intensity factor of the to-be-de-noised partial discharge signal; The method comprises the following steps: acquiring pulsation noise of a to-be-detected converter transformer at a preset position when the to-be-detected converter transformer is in a power-off static state, and determining a characteristic frequency spectrum of the pulsation noise in the to-be-detected converter transformer based on the pulsation noise; acquiring the pulsation noise of the to-be-detected converter transformer at the preset position on both sides of the network side winding when the to-be-detected converter transformer is in the power-off static state; wherein the preset position includes a high-voltage bushing end screen and a neutral point grounding position on both sides of the network side winding of the to-be-detected converter transformer; converting the pulsation noise based on Fourier transformation to obtain a pulsation noise frequency spectrum corresponding to the pulsation noise; taking an average noise frequency spectrum value of each frequency point in the pulsation noise frequency spectrum as the characteristic frequency spectrum of the pulsation noise in the to-be-detected converter transformer; The method comprises the following steps: based on a preset de-noising formula, removing, by a preset proportion, a signal corresponding to the characteristic frequency spectrum of the pulsation noise in the to-be-de-noised partial discharge signal, and obtaining a de-noised signal of the to-be-de-noised partial discharge signal; obtaining a similarity between the pulsation noise signal in the preset range and the de-noised signal according to the characteristic frequency spectrum value of the pulsation noise corresponding to each frequency point in the preset frequency range and the frequency spectrum value of the de-noised signal, and taking a formula corresponding to the similarity as the preset correlation coefficient formula; inputting the characteristic frequency spectrum value of the pulsation noise corresponding to each frequency point in the preset frequency range, the frequency spectrum value corresponding to the de-noised signal of the to-be-de-noised partial discharge signal, and the de-noising intensity factor corresponding to the de-noised signal into the preset correlation coefficient formula to output a corresponding correlation coefficient; adjusting the de-noising intensity factor in the preset correlation coefficient formula, and inputting the de-noised signal of the to-be-de-noised partial discharge signal corresponding to the adjusted de-noising factor and the characteristic frequency spectrum value of the pulsation noise corresponding to each frequency point in the preset frequency range into the preset correlation coefficient formula to obtain an adjusted correlation coefficient. acquiring a correlation coefficient corresponding to each of the adjusted correlation coefficients; the absolute value of the correlation coefficient corresponding to the minimum absolute value is taken as the optimal denoising intensity factor of the local discharge signal to be denoised, and the local discharge signal to be denoised is denoised based on the optimal denoising intensity factor.

2. The anti-interference method in transformer partial discharge detection according to claim 1, characterized in that, The method comprises the following steps: When the to-be-detected converter transformer is in the running state, the local discharge signal of the to-be-detected converter transformer at the preset position is detected, and the frequency spectrum of the local discharge signal is obtained, specifically comprising: When the to-be-detected converter transformer is in the running state, the local discharge signal of the to-be-detected converter transformer at the preset position is detected, and the frequency spectrum of the local discharge signal is obtained, specifically comprising:

3. The anti-interference method in transformer partial discharge detection according to claim 1, characterized in that, Based on the Fourier transform formula, the Fourier transform of the local discharge signal is carried out to obtain the frequency spectrum of the local discharge signal. wherein X 400k represents the denoised signal at 400 kHz, X 400k represents the local discharge signal to be denoised at 400 kHz, K represents a preset ratio, ωi represents each frequency point in a preset range, X(ω i ) represents the local discharge signal to be denoised, P(ω i ) represents the characteristic spectrum of the pulsating noise, Re[X(ωi)] represents the real part of the spectrum corresponding to the denoised signal, and Im[X(ωi)] represents the imaginary part of the spectrum corresponding to the denoised signal.

4. The anti-interference method in transformer partial discharge detection according to claim 1, characterized in that, The preset denoising formula is: where r denotes a correlation coefficient, X'(ω i ) denotes a denoised signal.

5. The anti-interference method in partial discharge detection of a transformer according to claim 1, characterized in that, The preset correlation coefficient formula is: The method further comprises the following steps: Based on the optimal denoising intensity factor, the optimal proportion of the local discharge signal to be denoised is determined; The optimal proportion, the local discharge signal to be denoised, and the signal corresponding to the characteristic frequency spectrum of the pulsating noise are input into the preset denoising formula; 6. The anti-interference method in partial discharge detection of a transformer according to claim 1, wherein, Based on the preset denoising formula, the signal corresponding to the optimal proportion in the local discharge signal to be denoised and the characteristic frequency spectrum of the pulsating noise is removed to obtain the denoised local discharge signal of the converter transformer. After filtering the pulsating noise in the preset frequency range, the method further comprises the following steps:

7. An anti-interference device in transformer partial discharge detection, used to implement the anti-interference method in transformer partial discharge detection according to any one of claims 1-6, characterized in that, After filtering the pulsating noise in the preset frequency range, the frequency spectrum corresponding to the local discharge signal to be denoised is subjected to inverse Fourier transform to obtain the denoised signal of the local discharge signal to be denoised corresponding to the converter transformer. The device comprises: at least one processor; and a memory in communication connection with the at least one processor; wherein The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to: acquire pulsating noise of the to-be-detected converter transformer at a preset position when the to-be-detected converter transformer is in a power-off static state, and determine the characteristic frequency spectrum of the pulsating noise in the to-be-detected converter transformer based on the pulsating noise; detect the local discharge signal of the to-be-detected converter transformer at the preset position when the to-be-detected converter transformer is in the running state, and obtain the frequency spectrum of the local discharge signal; acquire the local discharge signal in the preset frequency range as a local discharge signal to be denoised; The signal corresponding to the characteristic frequency spectrum of the pulsation noise in the local discharge signal to be denoised is removed at a preset ratio to filter the pulsation noise in the preset frequency range, and a denoised signal of the local discharge signal to be denoised is obtained; wherein the preset ratio is used to represent a denoising intensity factor of the local discharge signal to be denoised.

8. A non-transitory storage medium storing computer-executable instructions for performing the anti-interference method in the transformer partial discharge detection of any one of claims 1-6, characterized in that, The computer executable instructions comprise: acquiring pulsation noise of the to-be-detected converter transformer at a preset position when the to-be-detected converter transformer is in a power-off static state, so as to determine a characteristic frequency spectrum of the pulsation noise in the to-be-detected converter transformer based on the pulsation noise; detecting a local discharge signal of the to-be-detected converter transformer at a preset position when the to-be-detected converter transformer is in a running state, and obtaining a frequency spectrum of the local discharge signal; acquiring the local discharge signal in a preset frequency range as a local discharge signal to be denoised; The signal corresponding to the characteristic frequency spectrum of the pulsation noise in the local discharge signal to be denoised is removed at a preset ratio to filter the pulsation noise in the preset frequency range, and a denoised signal of the local discharge signal to be denoised is obtained; wherein the preset ratio is used to represent a denoising intensity factor of the local discharge signal to be denoised.

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