An active suppression method for narrowband interference of partial discharge ultrasonic signals

Abstract

The present invention provides a method for actively suppressing narrowband interference from partial discharge ultrasonic signals. The method comprises: determining the placement of ultrasonic sensors and noise sensors on the outer wall of a GIS; collecting partial discharge signals using the ultrasonic sensors in a laboratory environment; collecting partial discharge ultrasonic signals mixed with noise using the ultrasonic sensors in a field environment; collecting noise signals using the noise sensors; inputting the collected noise signals into a spectrum analyzer for spectrum analysis; extracting significant narrowband noise frequency bands in the frequency domain to determine their frequency bands and phase jitter; and actively suppressing narrowband noise in frequency bands where narrowband noise exists using a narrowband noise interference suppression formula. The present invention proposes a method for actively suppressing narrowband interference from ultrasonic partial discharge signals of GIS equipment in a field environment, ensuring the accuracy and reliability of interference suppression.

Description

Technical Field

[0001] The present invention relates to the field of ultrasonic sensor calibration and interference suppression, and in particular to a method for actively suppressing narrowband interference in a partial discharge signal received by an ultrasonic sensor. Background Art

[0002] Partial discharge is the main cause of insulation degradation in electrical equipment and is also an important indicator of insulation degradation. For the safety of the overall operation of the system, electrical equipment needs to be tested for partial discharge. Among them, ultrasonic sensors are widely used for partial discharge detection because of their high sensitivity and ability to use time delay for precise positioning. However, under actual working conditions, since ultrasonic sensors are placed on the outer wall of GIS equipment for a long time and the external environment is complex, there is a high probability that the sensors will wear out, rust, or be interfered with by noise from the substation environment. These conditions will affect the accuracy and sensitivity of the sensor in receiving partial discharge signals, resulting in the inability to detect and warn in time after electrical equipment failures, leading to serious consequences. Therefore, it is necessary to calibrate the sensors regularly.

[0003] Under real-world operating conditions, ultrasonic sensor calibration often suffers from complex background noise, which can reduce the accuracy and reliability of calibration results. This noise interference can originate from equipment operation, environmental factors, or other electromagnetic activity. To ensure timely warning of equipment failures, this background noise must be detected and suppressed. Research on active suppression methods for narrowband noise interference can provide a foundation for ultrasonic sensor calibration in noisy environments. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to solve the technical problem in the prior art that the local discharge ultrasonic signal of GIS equipment in a field environment has poor applicability to narrowband interference, which restricts the accuracy and reliability of interference suppression.

[0005] The present invention adopts the following technical solutions to solve the above technical problems. The method for actively suppressing narrowband interference of partial discharge ultrasonic signals includes:

[0006] S1. In a laboratory environment with little external interference, place a first ultrasonic sensor and a second ultrasonic sensor on the outer wall of a GIS pipe. Use the first ultrasonic sensor as an acoustic emission sensor to inject a partial discharge pulse to stimulate the first ultrasonic sensor to emit a partial discharge signal. Control the second ultrasonic sensor to detect and store the partial discharge ultrasonic signal of the GIS pipe, and obtain the maximum value of a relatively pure partial discharge ultrasonic signal.

[0007] S2. Under a field environment, arrange a third ultrasonic sensor and a fourth ultrasonic sensor on the outer wall of the GIS pipe, inject a partial discharge pulse into the third ultrasonic sensor to stimulate the third ultrasonic sensor to emit a partial discharge signal, and control the fourth ultrasonic sensor to detect and store a partial discharge ultrasonic signal mixed with background noise of the GIS pipe, thereby obtaining a maximum value of the partial discharge ultrasonic signal mixed with the background noise;

[0008] S3. Arrange a noise sensor, use the noise sensor to detect and save the background noise signal of the GIS pipe, and process it to obtain the maximum value of the background noise signal;

[0009] S4. Collecting a noise signal using the noise sensor, performing spectrum analysis on the noise signal, determining narrowband noise, and determining a frequency band range of the narrowband noise; and determining a phase jitter of the narrowband noise in each frequency band range;

[0010] S5. When the spectrum analysis confirms that the noise signal is the background noise, determine and store the frequency band of the background noise and the phase jitter, and process them to obtain a background noise suppression formula;

[0011] S6. Using the background noise suppression formula, integrating and processing to obtain narrowband noise suppression waveform data, and storing the background noise suppression waveform data in the host computer;

[0012] S7. Perform mixed processing on the partial discharge ultrasonic signal mixed with background noise and the background noise suppression waveform data to obtain a denoised partial discharge ultrasonic signal.

[0013] This invention proposes an active suppression strategy for narrowband interference from partial discharge ultrasonic signals from GIS equipment in field environments. This strategy can mitigate the effects of complex background noise during ultrasonic sensor calibration, improving the accuracy and reliability of calibration results and interference suppression. The invention can also remove narrowband interference in the field. Specifically, it addresses the simultaneous presence of noise and partial discharge in the field.

[0014] In a more specific technical solution, in S1, a first ultrasonic sensor and a second ultrasonic sensor are arranged on the outer wall of the GIS pipe according to a preset arrangement position and a distance, and the first ultrasonic sensor and the second ultrasonic sensor are arranged on a horizontal line.

[0015] According to the following logic, the second ultrasonic sensor is arranged at a distance l from the first ultrasonic sensor, and l is calculated using the following formula:

[0016]

[0017] Wherein, ρ1 is the density of sulfur hexafluoride in the GIS tube; ρ2 is the density of air; v is the speed of sound in air, which is generally 340 m / s; t r is the fall time of the partial discharge pulse injected into the ultrasonic sensor.

[0018] In a more specific technical solution, in S1, a partial discharge pulse is injected into the first ultrasonic sensor to stimulate the first ultrasonic sensor to emit a partial discharge signal;

[0019] Control the second ultrasonic sensor to detect the relatively pure partial discharge ultrasonic signal of the GIS pipe;

[0020] The partial discharge ultrasonic signal is stored in the host computer and processed to obtain a relatively pure maximum value U1 of the partial discharge ultrasonic signal.

[0021] In a more specific technical solution, in S2, the preset layout positions and distances of the third ultrasonic sensor and the fourth ultrasonic sensor are the same as those of the first ultrasonic sensor and the second ultrasonic sensor in S1.

[0022] injecting a partial discharge pulse into the third ultrasonic sensor to stimulate the third ultrasonic sensor to emit a partial discharge signal;

[0023] controlling the fourth ultrasonic sensor to detect the partial discharge ultrasonic signal mixed with the background noise of the GIS pipe;

[0024] The partial discharge ultrasonic signal is stored in the host computer and processed to obtain the maximum value U2 of the partial discharge ultrasonic signal mixed with background noise.

[0025] In a more specific technical solution, in S3, a noise sensor is arranged at the installation position of the fourth ultrasonic sensor.

[0026] In a more specific technical solution, in S3, the noise sensor is controlled to detect the background noise signal of the GIS pipe;

[0027] The background noise signal is saved in the host computer and processed to obtain the maximum value U3 of the background noise signal.

[0028] In a more specific technical solution, in S4, a noise sensor is used to collect a noise signal, and a spectrum analysis is performed on the noise signal. If the peak value of a frequency band in the image obtained by the spectrum analysis is significantly higher than the peak value of the white noise in the entire frequency band, and the noise amplitudes in the remaining frequency bands are similar to the amplitude of the white noise in the entire frequency band, then it is confirmed that narrowband noise exists in the frequency band, and the frequency band range of the narrowband noise is confirmed;

[0029] A spectrum analyzer is used to test and determine the phase jitter of narrowband noise in each frequency band.

[0030] This paper, by studying methods for actively suppressing narrowband noise interference, can provide a foundation for ultrasonic sensor calibration in noise-affected environments. Taking into account the inherent properties of GIS equipment and the comparison of noise signals with mixed noise partial discharge signals, the present invention identifies the narrowband noise frequency band and uses a denoising formula to specifically remove narrowband noise.

[0031] In a more specific technical solution, in S4, if the spectrum analysis confirms that the noise signal is narrowband noise, the frequency bands f1, f2, ..., f in which the narrowband noise is located are determined. n , phase jitter φ1(t), φ2(t)…φ n (t), where n is the maximum number of narrowband noise frequency bands;

[0032] Set the frequency band f1, f2…f n , phase jitter φ1(t), φ2(t)…φ n (t) is saved in the host computer and processed to obtain the background noise suppression formula.

[0033] In a more specific technical solution, the background noise suppression formula is expressed using the following logic:

[0034]

[0035] Wherein, U1 represents the maximum value of the signal received by the second ultrasonic sensor; U2 represents the maximum value of the signal received by the fourth ultrasonic sensor; U3 represents the maximum value of the signal received by the noise sensor; a represents the outer diameter of the conductor inside the GIS tube; b represents the inner diameter of the GIS tube shell; V represents the voltage level of the GIS tube; and SNR represents the signal-to-noise ratio.

[0036] In a more specific technical solution, in S7, the following logic is used to process and obtain the denoised partial discharge ultrasonic signal k(t):

[0037] k(t)=f(t)+g(t)

[0038] Wherein, f(t) represents the partial discharge ultrasonic signal mixed with narrowband noise measured by the fourth ultrasonic sensor.

[0039] Compared with the prior art, the present invention has the following advantages:

[0040] The present invention considers an active suppression strategy for narrowband interference of locally discharged ultrasonic signals of GIS equipment in a field environment. It can avoid the influence of complex background noise when calibrating ultrasonic sensors, and improve the accuracy and reliability of calibration results and interference suppression operations.

[0041] Since noise interference in the prior art comes from equipment operation, environmental factors or other electromagnetic activities, the present invention detects the above background noise, identifies the type and characteristics of the noise, and ensures timely warning of equipment failure.

[0042] The present invention studies a method for actively suppressing narrowband noise interference, and can provide a basis for a calibration method of an ultrasonic sensor in an environment affected by noise.

[0043] The present invention solves the technical problem in the prior art that the local discharge ultrasonic signal of GIS equipment in a field environment has poor applicability to narrowband interference, which restricts the accuracy and reliability of interference suppression. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Schematic diagram of the basic steps of the method for actively suppressing narrowband interference of partial discharge ultrasonic signals according to Example 1 of the present invention;

[0045] Figure 2 This is a schematic diagram of the ultrasonic sensor arrangement in a laboratory environment according to Example 1 of the present invention;

[0046] Figure 3 This is a schematic diagram of the ultrasonic sensor arrangement in a field environment according to Example 1 of the present invention;

[0047] Figure 4 This is a schematic diagram of the noise sensor configuration according to Example 1 of the present invention;

[0048] Figure 5 This is a schematic diagram of a partial discharge ultrasonic pulse signal according to Example 1 of the present invention;

[0049] Figure 6 This is a spectrum diagram of the background noise signal measured by the noise sensor in the field test of Example 1 of the present invention after spectrum analysis;

[0050] Figure 7 This is a phase diagram of the background noise signal measured by the noise sensor in the field test of Example 1 of the present invention after spectrum analysis. DETAILED DESCRIPTION

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0052] Example 1

[0053] like Figure 1 As shown, the method for actively suppressing narrowband interference of partial discharge ultrasonic signals provided by the present invention includes the following basic steps:

[0054] Step S1: In a laboratory environment, a first ultrasonic sensor and a second ultrasonic sensor are arranged on the outer wall of a GIS pipe. The first ultrasonic sensor is used as an acoustic emission sensor to inject a partial discharge pulse to stimulate the first ultrasonic sensor to emit a partial discharge signal. The second ultrasonic sensor detects and stores the partial discharge ultrasonic signal of the GIS pipe to obtain the maximum value of a relatively pure partial discharge ultrasonic signal.

[0055] like Figure 2 As shown, in this embodiment, tested in a laboratory environment, a first ultrasonic sensor was placed on the outer wall of a GIS pipe at a distance l1 from any port, and a second ultrasonic sensor was placed on the outer wall at a distance l from the first ultrasonic sensor, so that the first and second ultrasonic sensors were aligned horizontally. Here, l1 is 200 mm, and l is obtained through calculation.

[0056] According to the following logic, the second ultrasonic sensor is arranged at a distance l from the first ultrasonic sensor, and l is calculated using the following formula:

[0057]

[0058] Wherein, ρ1 is the density of sulfur hexafluoride in the GIS tube; ρ2 is the density of air; v is the speed of sound in air, which is generally 340 m / s; t r is the fall time of the partial discharge pulse injected into the ultrasonic sensor.

[0059] Inject the first ultrasonic sensor into Figure 5 The partial discharge pulse shown stimulates it to emit a partial discharge signal, controls the second ultrasonic sensor to detect the relatively pure partial discharge ultrasonic signal of the GIS tube, and stores the data in the host computer, and processes it to obtain the relatively pure partial discharge ultrasonic signal U1 of the GIS tube.

[0060] Step S2: testing under the field environment of this embodiment, such as Figure 3 As shown, the preset layout positions and distances of the third ultrasonic sensor and the fourth ultrasonic sensor are the same as those of the first ultrasonic sensor and the second ultrasonic sensor in S1. Figure 5 The partial discharge pulse shown stimulates it to emit a partial discharge signal, controls the fourth ultrasonic sensor to detect the partial discharge ultrasonic signal of the GIS tube mixed with the background noise, and saves the data in the host computer, and processes it to obtain the maximum value U2 of the partial discharge ultrasonic signal of the mixed background noise.

[0061] Step S3, as Figure 4 As shown, a noise sensor is arranged on the outer wall of the GIS pipe to detect and save the background noise signal of the GIS pipe and obtain the maximum value of the background noise signal;

[0062] In this embodiment, a noise sensor is placed at the same location as the fourth ultrasonic sensor in step S2. The noise sensor is controlled to detect the background noise signal of the GIS pipe, and the data is stored in the host computer, and processed to obtain the maximum value U3 of the background noise signal.

[0063] Step S4: using the noise sensor to collect noise signals, performing spectrum analysis on the received noise signals, confirming that the noise is narrowband noise and the frequency range of the narrowband noise; and determining the phase jitter of the narrowband noise in each frequency band;

[0064] In this embodiment, a 10s noise signal is collected by a noise sensor, such as Figure 6 、 Figure 7 As shown, in this embodiment, spectrum analysis is performed on the received noise signal. If the spectrum analysis results in an image with relatively high peaks in one or more frequency bands and the noise amplitudes in the remaining frequency bands are similar to the amplitude of white noise occurring across the entire frequency band, the noise is confirmed to be narrowband noise, and the frequency band range of the narrowband noise is determined. The phase jitter of the narrowband noise in each frequency band is determined using a spectrum analyzer.

[0065] Step S5: When the spectrum analysis confirms that the collected noise is narrowband noise, determine and store the frequency band and phase jitter of the narrowband noise;

[0066] In this embodiment, if the spectrum analysis confirms that the collected noise is narrowband noise, the frequency bands f1, f2, ..., f in which the narrowband noise is located are determined. n and phase jitter φ1(t), φ2(t)…φ n (t), n takes the maximum number of narrowband noise frequency bands and saves the data in the host computer. The background noise suppression formula is obtained:

[0067]

[0068] Wherein, U1 represents the maximum value of the signal received by the second ultrasonic sensor; U2 represents the maximum value of the signal received by the fourth ultrasonic sensor; U3 represents the maximum value of the signal received by the noise sensor; a represents the outer diameter of the conductor inside the GIS tube; b represents the inner diameter of the GIS tube shell; V represents the voltage level of the GIS tube; and SNR represents the signal-to-noise ratio.

[0069] Step S6: Calculate and integrate to obtain background noise suppression waveform data, and save the waveform in the host computer;

[0070] Step S7: Mix the background noise mixed partial discharge ultrasonic signal obtained in the above step S2 with the background noise suppression waveform stored in the host computer in step S6 to obtain a denoised partial discharge ultrasonic signal k(t).

[0071] k(t)=f(t)+g(t)

[0072] Wherein, f(t) represents the partial discharge ultrasonic signal mixed with background noise measured by the fourth ultrasonic sensor.

[0073] In summary, the present invention considers an active suppression strategy for narrowband interference of locally discharged ultrasonic signals of GIS equipment in a field environment. It can avoid the influence of complex background noise when calibrating ultrasonic sensors, and improve the accuracy and reliability of calibration results and interference suppression operations.

[0074] The present invention studies a method for actively suppressing narrowband noise interference, and can provide a basis for a calibration method of an ultrasonic sensor in an environment affected by noise.

[0075] The present invention solves the technical problem in the prior art that the local discharge ultrasonic signal of GIS equipment in a field environment has poor applicability to narrowband interference, which restricts the accuracy and reliability of interference suppression.

[0076] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An active suppression method for narrowband interference of partial discharge ultrasonic signals, characterized in that: The method comprises: S1. In a laboratory environment with little external interference, place a first ultrasonic sensor and a second ultrasonic sensor on the outer wall of a GIS pipe. Use the first ultrasonic sensor as an acoustic emission sensor to inject a partial discharge pulse, stimulating it to emit a partial discharge signal. Control the second ultrasonic sensor to detect and store the partial discharge ultrasonic signal from the GIS pipe, and obtain the maximum value of a relatively pure partial discharge ultrasonic signal. S2. Under a field environment, arrange a third ultrasonic sensor and a fourth ultrasonic sensor on the outer wall of the GIS pipe, inject a partial discharge pulse into the third ultrasonic sensor to stimulate it to emit a partial discharge signal, and control the fourth ultrasonic sensor to detect and store a partial discharge ultrasonic signal mixed with background noise of the GIS pipe, thereby obtaining a maximum value of the partial discharge ultrasonic signal mixed with the background noise; S3. Arrange a noise sensor, use the noise sensor to detect and save the background noise signal of the GIS pipe, and process it to obtain the maximum value of the background noise signal; S4. Collecting a noise signal using the noise sensor, performing spectrum analysis on the noise signal, determining narrowband noise, and determining a frequency band range of the narrowband noise; and determining a phase jitter of the narrowband noise in each frequency band range; S5. When the spectrum analysis confirms that the noise signal is the background noise, determine and store the frequency band of the background noise and the phase jitter, and process them to obtain a background noise suppression formula; S6. Using the background noise suppression formula, integrating and processing to obtain narrowband noise suppression waveform data, and storing the background noise suppression waveform data in a host computer; S7. Perform mixed processing on the partial discharge ultrasonic signal mixed with background noise and the background noise suppression waveform data to obtain a denoised partial discharge ultrasonic signal.

2. The method for actively suppressing narrowband interference of partial discharge ultrasonic signals according to claim 1, characterized in that: In S1, the first ultrasonic sensor and the second ultrasonic sensor are arranged on the outer wall of the GIS tube according to a preset arrangement position and arrangement distance, and the first ultrasonic sensor and the second ultrasonic sensor are arranged on a horizontal line. The arrangement distance is to arrange the second ultrasonic sensor at a distance of l from the first ultrasonic sensor, and l is calculated using the following formula: Wherein, ρ1 is the density of sulfur hexafluoride in the GIS tube; ρ2 is the density of air; v is the speed of sound in air, which is generally 340 m / s; t r is the fall time of the partial discharge pulse injected into the ultrasonic sensor.

3. The method for actively suppressing narrowband interference of partial discharge ultrasonic signals according to claim 1, characterized in that: In S1, a Gaussian pulse is injected into the first ultrasonic sensor to stimulate the first ultrasonic sensor to emit a partial discharge signal; the second ultrasonic sensor is controlled to detect a relatively pure partial discharge ultrasonic signal of the GIS pipe; The partial discharge ultrasonic signal is stored in a host computer and processed to obtain the relatively pure maximum value U1 of the partial discharge ultrasonic signal.

4. The method for actively suppressing narrowband interference of partial discharge ultrasonic signals according to claim 1, characterized in that: In S2, the third ultrasonic sensor and the fourth ultrasonic sensor are arranged on the outer wall of the GIS pipe according to the preset layout position and layout distance. The third ultrasonic sensor and the fourth ultrasonic sensor are set on a horizontal line. The preset layout position and layout distance of the third ultrasonic sensor and the fourth ultrasonic sensor are the same as those of the first ultrasonic sensor and the second ultrasonic sensor in S1.

5. The method for actively suppressing narrowband interference of partial discharge ultrasonic signals according to claim 1, characterized in that: In S2, a Gaussian pulse is injected into the third ultrasonic sensor to stimulate the third ultrasonic sensor to emit a partial discharge signal; the fourth ultrasonic sensor is controlled to detect the partial discharge ultrasonic signal mixed with the background noise of the GIS tube; The partial discharge ultrasonic signal is stored in a host computer, and processed to obtain a maximum value U2 of the partial discharge ultrasonic signal mixed with the background noise.

6. The method for actively suppressing narrowband interference of partial discharge ultrasonic signals according to claim 1, characterized in that: In S3, the noise sensor is arranged at the installation position of the fourth ultrasonic sensor, and the noise sensor is controlled to detect the background noise signal of the GIS pipe; The background noise signal is stored in a host computer and processed to obtain the maximum value U3 of the background noise signal.

7. The method for actively suppressing narrowband interference of partial discharge ultrasonic signals according to claim 1, characterized in that: In S4, the noise signal is collected for 10 seconds using the noise sensor; a spectrum analysis is performed on the noise signal. If the peak value of a frequency band in the image obtained by the spectrum analysis is significantly higher than the peak value of the white noise in the full frequency band, and the noise amplitudes in the remaining frequency bands are similar to the amplitude of the white noise in the full frequency band, then it is confirmed that narrowband noise exists in the frequency band, and the frequency band range of the narrowband noise is confirmed; A spectrum analyzer is used to perform testing to determine the phase jitter of the narrowband noise in each frequency band.

8. The method for actively suppressing narrowband interference of partial discharge ultrasonic signals according to claim 1, characterized in that: In the step S5, if the spectrum analysis confirms that the noise signal is the narrowband noise, the frequency bands f1, f2, ..., f of the narrowband noise are determined. n , the phase jitter φ1(t), φ2(t)…φ n (t), where n is the maximum number of narrowband noise frequency bands; The frequency bands f1, f2...f n , the phase jitter φ1(t), φ2(t)…φ n (t) The background noise suppression formula is obtained by processing the data in the host computer.

9. The method for actively suppressing narrowband interference of partial discharge ultrasonic signals according to claim 1, characterized in that: The background noise suppression formula is expressed using the following logic: Wherein, U1 represents the maximum value of the signal received by the second ultrasonic sensor; U2 represents the maximum value of the signal received by the fourth ultrasonic sensor; U3 represents the maximum value of the signal received by the noise sensor; V represents the voltage level of the GIS tube; SNR represents the signal-to-noise ratio.

10. The method for actively suppressing narrowband interference of partial discharge ultrasonic signals according to claim 1, characterized in that: In S7, the following logic is used to obtain the denoised partial discharge ultrasonic signal k(t): k(t)=f(t)+g(t) Wherein, f(t) represents the partial discharge ultrasonic signal mixed with background noise measured by the fourth ultrasonic sensor.

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