Active suppression method for narrow-band interference of partial discharge ultrasonic signal

Abstract

The invention provides an active suppression method for narrow-band interference of a partial discharge ultrasonic signal. The method comprises the following steps: determining the arrangement positions of an ultrasonic sensor and a noise sensor on the outer wall of a GIS (Gas Insulated Switchgear); in a laboratory environment, a partial discharge signal is collected through an ultrasonic sensor; the method comprises the following steps: in a field environment, collecting partial discharge ultrasonic signals of mixed noise through an ultrasonic sensor; collecting a noise signal through a noise sensor; inputting the collected noise signal into a spectrum analyzer for spectrum analysis; extracting an obvious narrow-band noise frequency band in a frequency domain, and determining the frequency band and phase jitter of the narrow-band noise frequency band; and active suppression of the narrow-band noise is carried out on the frequency band with the narrow-band noise through the suppression formula of the narrow-band noise interference. The invention provides an active suppression method for narrowband interference of ultrasonic partial discharge signals of GIS equipment in a field environment, and the accuracy and reliability of interference suppression are ensured.

Description

Technical Field

[0001] The 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 of electrical equipment and an important indicator of insulation degradation. In order to ensure 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 due to their high sensitivity and ability to use time delays 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 be worn, rusted, or interfered by noise from the substation environment. These conditions will affect the accuracy and sensitivity of the sensor in receiving partial discharge signals, resulting in failures of electrical equipment and the inability to detect warnings in time, leading to serious consequences. Therefore, it is necessary to calibrate the sensors regularly.

[0003] In actual working conditions, when calibrating ultrasonic sensors, the accuracy and reliability of the calibration results are often reduced due to the influence of complex background noise. These noise interferences may come from equipment operation, environmental factors or other electromagnetic activities. In order to ensure timely warning of equipment failure, these background noises must be detected and suppressed. By studying the active suppression method of narrowband noise interference, we can provide a basis for the calibration method of ultrasonic sensors in noise-affected environments. Summary of the invention

[0004] The technical problem to be solved by the present invention is to solve the technical problem that the local discharge ultrasonic signal of GIS equipment in the field environment has poor applicability to narrowband interference in the prior art, 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 active suppression method of narrowband interference of partial discharge ultrasonic signals includes:

[0006] S1. In a laboratory environment with little external interference, a first ultrasonic sensor and a second ultrasonic sensor are arranged on the outer wall of a GIS pipe, and 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, and the second ultrasonic sensor is controlled to detect and save the partial discharge ultrasonic signal of the GIS pipe to obtain the maximum value of a relatively pure partial discharge ultrasonic signal;

[0007] S2. Under the field environment, a third ultrasonic sensor and a fourth ultrasonic sensor are arranged on the outer wall of the GIS pipe, a partial discharge pulse is injected into the third ultrasonic sensor to stimulate the third ultrasonic sensor to send a partial discharge signal, and the fourth ultrasonic sensor is controlled to detect and save the partial discharge ultrasonic signal of the mixed background noise of the GIS pipe to obtain the maximum value of the partial discharge ultrasonic signal of the mixed background noise;

[0008] S3, arranging a noise sensor, using the noise sensor to detect and save the background noise signal of the GIS pipe, and processing to obtain the maximum value of the background noise signal;

[0009] S4, using the noise sensor to collect noise signals, perform spectrum analysis on the noise signals, perform narrowband noise determination, and determine the frequency band range of the narrowband noise; determine the 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 where the background noise is located 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, performing 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] The present invention considers an active suppression strategy for narrowband interference of partial discharge ultrasonic signals of GIS equipment in a field environment, which 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. The present invention can remove narrowband interference on site. Specifically, the present invention performs denoising in the case where noise and partial discharge exist at the same time on site.

[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] In the formula, ρ 1is the density of sulfur hexafluoride in the GIS tube; ρ 2 is the density of air; v is the speed of sound in air, generally 340m / s; t r It 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 tube;

[0020] The partial discharge ultrasonic signal is saved in the host computer and processed to obtain the purer maximum value U of the partial discharge ultrasonic signal. 1 .

[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 saved in the host computer and processed to obtain the maximum value U of the partial discharge ultrasonic signal mixed with background noise. 2 .

[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 the maximum value U of the background noise signal is obtained after processing. 3 .

[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 of an image obtained by the spectrum analysis is significantly higher than the peak value of white noise in the full frequency band, and the noise amplitudes of the remaining frequency bands are similar to the amplitude of 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;

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

[0030] The present invention studies the active suppression method of narrowband noise interference, which can provide a basis for the calibration method of ultrasonic sensors in noise-affected environments. The present invention considers the properties of the GIS equipment itself and the comparison of the partial discharge signal of the noise signal and the mixed noise, and then uses the denoising formula to remove the narrowband noise in a targeted manner by determining the narrowband noise frequency band.

[0031] In a more specific technical solution, in S4, if the spectrum analysis confirms that the noise signal is narrow-band noise, the frequency band f of the narrow-band noise is determined. 1 、f 2 …f n 、Phase jitter φ 1 (t),φ 2 (t)…φ n (t), where n is the maximum number of narrowband noise frequency bands;

[0032] The frequency band f 1 、f 2 …f n 、Phase jitter φ 1 (t),φ 2 (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] Where U 1 represents the maximum value of the signal received by the second ultrasonic sensor; U 2 The maximum value of the signal received by the fourth ultrasonic sensor; 3 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; 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 local discharge ultrasonic signal mixed with narrow-band noise measured by the fourth ultrasonic sensor.

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

[0040] The present invention takes into account an active suppression strategy for narrowband interference of local discharge ultrasonic signals of GIS equipment in a field environment, which 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 the 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 the active suppression method of narrowband noise interference, and can provide a basis for the calibration method of ultrasonic sensors 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 This is a schematic diagram of the basic steps of the method for actively suppressing narrow-band 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 Embodiment 1 of the present invention;

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

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

[0049] Figure 6 The 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 It 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] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] Example 1

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

[0054] Step S1, in a laboratory environment, arrange a first ultrasonic sensor and a second ultrasonic sensor on the outer wall of a GIS pipe, inject a partial discharge pulse into the first ultrasonic sensor as an acoustic emission sensor to stimulate the first ultrasonic sensor to emit a partial discharge signal, and the second ultrasonic sensor detects and saves 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 the laboratory environment of this embodiment, at any port l of the GIS pipe 1 A first ultrasonic sensor is arranged on the outer wall at a distance of 1, and a second ultrasonic sensor is arranged on the outer wall at a distance of 1 from the first ultrasonic sensor, so that the first ultrasonic sensor and the second ultrasonic sensor are on a horizontal line. 1 is 200mm, and l is obtained by 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] In the formula, ρ 1 is the density of sulfur hexafluoride in the GIS tube; ρ 2 is the density of air; v is the speed of sound in air, generally 340m / s; t r It is the fall time of the partial discharge pulse injected into the ultrasonic sensor.

[0059] Inject the first ultrasonic sensor with Figure 5 The partial discharge pulse shown in the figure stimulates it to send out a partial discharge signal, controls the second ultrasonic sensor to detect the relatively pure partial discharge ultrasonic signal of the GIS tube, and saves the data in the host computer, and processes to obtain the relatively pure partial discharge ultrasonic signal U of the GIS tube. 1 .

[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 in the figure stimulates it to send out a partial discharge signal, controls the fourth ultrasonic sensor to detect the partial discharge ultrasonic signal of the mixed background noise of the GIS tube, and saves the data in the host computer, and processes to obtain the maximum value U of the partial discharge ultrasonic signal of the mixed background noise 2 .

[0061] Step S3: 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 arranged at the same position as the fourth ultrasonic sensor in the aforementioned 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 the maximum value U of the background noise signal is obtained by processing. 3 .

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

[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, the received noise signal is subjected to spectrum analysis. If the image obtained by the spectrum analysis has a relatively high peak value in one or more frequency bands and the noise amplitudes in the remaining frequency bands are similar to the amplitude of the white noise in the full frequency band, the noise is confirmed to be narrowband noise, and the frequency band range of the narrowband noise is confirmed. The phase jitter of the narrowband noise in each frequency band range is determined by spectrum analyzer testing.

[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 narrow-band noise, the frequency band f of the narrow-band noise is determined. 1 、f 2 …f n and phase jitter φ 1 (t),φ 2 (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] Where U 1 represents the maximum value of the signal received by the second ultrasonic sensor; U 2 The maximum value of the signal received by the fourth ultrasonic sensor; 3 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; SNR represents the signal-to-noise ratio.

[0069] Step S6, calculating and integrating to obtain background noise suppression waveform data, and saving the waveform in the host computer;

[0070] Step S7, mixing the partial discharge ultrasonic signal mixed with background noise 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 local discharge ultrasonic signals of GIS equipment in field environments, which 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 the active suppression method of narrowband noise interference, and can provide a basis for the calibration method of ultrasonic sensors 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 the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. 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 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, a first ultrasonic sensor and a second ultrasonic sensor are arranged on the outer wall of a GIS pipe, and 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, and the second ultrasonic sensor is controlled to detect and save the partial discharge ultrasonic signal of the GIS pipe to obtain the maximum value of a relatively pure partial discharge ultrasonic signal; S2. Under the field environment, a third ultrasonic sensor and a fourth ultrasonic sensor are arranged on the outer wall of the GIS pipe, a partial discharge pulse is injected into the third ultrasonic sensor to stimulate the third ultrasonic sensor to send a partial discharge signal, and the fourth ultrasonic sensor is controlled to detect and save the partial discharge ultrasonic signal of the mixed background noise of the GIS pipe to obtain the maximum value of the partial discharge ultrasonic signal of the mixed background noise; S3, arranging a noise sensor, using the noise sensor to detect and save the background noise signal of the GIS pipe, and processing to obtain the maximum value of the background noise signal; S4, using the noise sensor to collect noise signals, perform spectrum analysis on the noise signals, perform narrowband noise determination, and determine the frequency band range of the narrowband noise; determine the 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 where the background noise is located 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 the host computer; S7, performing 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 background noise 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 pipe according to the preset arrangement position and the arrangement distance, and the first ultrasonic sensor and the second ultrasonic sensor are arranged on a horizontal line, wherein 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 propagation speed of sound in air, which is generally 340 m / s; t r It 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, the 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 tube; 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 background noise 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, and the third ultrasonic sensor and the fourth ultrasonic sensor are set on a horizontal line, and the preset layout position and 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, the 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 sensor is used to collect the noise signal for 10 seconds; a spectrum analysis is performed on the noise signal. If the peak value of the frequency band of 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 amplitude of the remaining frequency bands is similar to the amplitude of the white noise in the full frequency band, 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 a test 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 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 background noise suppression formula in the host computer.

9. The method for actively suppressing narrowband interference of partial discharge ultrasonic signals according to claim 9, characterized in that: The background noise suppression formula is expressed using the following logic: In the formula, 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; 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 process and 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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