Porcelain insulator nondestructive testing device and method based on chirp modulation photoacoustic spectroscopy

Abstract

The invention discloses a porcelain insulator nondestructive testing device and method based on chirp modulation photoacoustic spectroscopy. The device comprises a signal generator, a signal processing module and a signal processing module, the laser is connected with the signal generator; the power amplifier is connected with the laser; the laser collimator is connected with the power amplifier; and the signal collector collects the sound wave signals, converts the sound wave signals into electric signals, transmits the electric signals to the computer through a cable for data processing, obtains a spectrogram of the sound wave signals, and judges whether defects exist in the porcelain insulator or not according to the spectrogram. According to the porcelain insulator nondestructive testing device adopting chirp modulation and photoacoustic spectroscopy, characteristic frequency scanning is achieved through chirp modulation, a porcelain insulator acoustic signal spectrogram is obtained through the solid photoacoustic effect, non-power-cut nondestructive testing of porcelain insulators can be achieved, and the detection efficiency of porcelain insulator defects is greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of insulator detection, and in particular relates to a non-destructive detection device and method for porcelain insulators based on chirp-modulated photoacoustic spectroscopy. Background Art

[0002] Porcelain insulators play a vital role in power systems. They not only provide rigid support or suspension for live equipment but also act as insulation and protection. They possess excellent properties such as high-temperature resistance, wear resistance, and corrosion resistance. During live operation, porcelain insulators are subject to a variety of mechanical, thermal, electrical, and environmental factors, potentially forming microcracks on their surfaces and within their interiors. Over time, these microcracks gradually expand, eventually leading to fracture and damage in the porcelain insulator, thus compromising the safe operation of the power system. Therefore, regular testing and evaluation of the mechanical properties of porcelain insulators to promptly identify defects is crucial for ensuring the safe and stable operation of power systems.

[0003] Currently, there are four main nondestructive testing methods for porcelain insulators: infrared thermometry, ultrasonic testing, ultraviolet testing, and industrial CT. Infrared thermometry is relatively difficult to detect early cracks in porcelain insulators, and the results are significantly affected by the environment. Ultrasonic testing, while relatively mature among nondestructive testing methods, requires a power outage and has low detection efficiency. Ultraviolet testing is suitable for detecting microscopic cracks on the surface of porcelain insulators but cannot detect internal defects. Industrial CT can detect internal defects in porcelain insulators with high detection accuracy, but requires the insulators to be removed from the site and tested in a laboratory. Therefore, there is an urgent need to develop a nondestructive testing method for internal defects in porcelain insulators that does not require a power outage to improve the efficiency of defect detection in porcelain insulators. Summary of the Invention

[0004] The present invention provides a nondestructive testing device and method for porcelain insulators based on chirp-modulated photoacoustic spectroscopy, which are used to solve the technical problem of low efficiency in defect detection of porcelain insulators.

[0005] In a first aspect, the present invention provides a nondestructive testing device for porcelain insulators based on chirp-modulated photoacoustic spectroscopy, comprising:

[0006] Signal generator;

[0007] a laser connected to the signal generator;

[0008] a power amplifier connected to the laser;

[0009] a laser collimator connected to the power amplifier; and

[0010] The signal collector collects the acoustic wave signal and converts it into an electrical signal, which is then transmitted to a computer via a cable for data processing. The spectrum of the acoustic wave signal is obtained, and the presence of defects in the porcelain insulator is determined based on the spectrum.

[0011] Furthermore, the signal generator is connected to the input end of the laser through a cable to provide an excitation signal for the laser.

[0012] Furthermore, the output end of the laser is connected to the input end of the power amplifier through an optical fiber to enhance the power of the output laser.

[0013] Furthermore, the output end of the power amplifier is connected to the input end of the laser collimator through an optical fiber to collimate the direction of the output laser.

[0014] Furthermore, the output end of the laser collimator is perpendicular to the porcelain insulator, and the laser collimator and the porcelain insulator do not contact each other, so that the output laser is vertically irradiated on the surface of the porcelain insulator to generate an acoustic wave signal through the photoacoustic effect.

[0015] Furthermore, the input end of the signal collector is perpendicular to the porcelain insulator, the signal collector and the porcelain insulator do not contact each other, collects the acoustic wave signal, and converts the acoustic wave signal into an electrical signal.

[0016] Furthermore, the output end of the signal collector is connected to a computer via a cable, and the acoustic wave signal is transmitted to the computer for data processing to obtain a spectrum diagram of the acoustic wave signal.

[0017] In a second aspect, the present invention provides a nondestructive testing method for porcelain insulators based on chirp-modulated photoacoustic spectroscopy, comprising the following steps:

[0018] S1: A signal generator is used to generate a chirped square wave signal whose frequency changes with time. The chirped square wave signal is transmitted to the input end of the laser through a cable to power the laser, so that the laser generates a periodically changing laser signal.

[0019] S2: The laser output is connected to the power amplifier input via an optical fiber to amplify the energy of the laser signal;

[0020] S3: The output of the power amplifier is connected to the input of the laser collimator through an optical fiber to collimate the direction of the laser;

[0021] S4: The chirped-modulated laser signal after amplification and collimation is vertically irradiated onto the surface of the porcelain insulator. The porcelain insulator absorbs the laser energy and produces a solid photoacoustic effect, emitting an acoustic wave signal with the same frequency as the laser signal.

[0022] S5: Use a signal collector to collect acoustic signals and convert them into electrical signals, which are then transmitted to a computer via a cable for data processing. A spectrum of the acoustic signals is obtained, and the presence of defects in the porcelain insulator is determined based on the spectrum.

[0023] The present application discloses a nondestructive testing device and method for porcelain insulators based on chirp-modulated photoacoustic spectroscopy. The nondestructive testing device for porcelain insulators adopts chirp modulation and photoacoustic spectroscopy, realizes characteristic frequency scanning through chirp modulation, and obtains the acoustic signal spectrum of the porcelain insulator through the solid photoacoustic effect, which can realize nondestructive testing of porcelain insulators without power outage and greatly improve the detection efficiency of porcelain insulator defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0025] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0026] Figure 2 Schematic diagram of the chirp modulation signal of the present invention.

[0027] In the figure: 1. Signal generator; 2. Laser; 3. Optical fiber; 4. Power amplifier; 5. Optical fiber; 6. Laser collimator; 7. Porcelain insulator; 8. Signal collector; 9. Computer. DETAILED DESCRIPTION

[0028] 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 accompanying drawings of 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.

[0029] like Figure 1As shown, the present invention provides a technical solution: a nondestructive testing device for porcelain insulators based on chirp-modulated photoacoustic spectroscopy. The device comprises a signal generator, a laser, an optical fiber, a power amplifier, a laser collimator, a porcelain insulator, a signal collector, and a computer. Signal generator 1 is connected to the input of laser 2 via a cable to provide an excitation signal to the laser. The output of laser 2 is connected to the input of power amplifier 4 via optical fiber 3 to amplify the power of the output laser. The output of power amplifier 4 is connected to the input of laser collimator 6 via optical fiber 5 to collimate the direction of the output laser. The output of laser collimator 6 is perpendicular to porcelain insulator 7, but not in contact with it. This allows the output laser to strike the surface of porcelain insulator 7 perpendicularly, generating an acoustic signal via the photoacoustic effect. The input of signal collector 8 is perpendicular to porcelain insulator 7, but not in contact with it. The device collects the acoustic signal and converts it into an electrical signal. The output of signal collector 8 is connected to computer 9 via a cable to transmit the acoustic signal to the computer for data processing and to obtain a spectrum of the acoustic signal.

[0030] In this embodiment, a signal generator is used to generate a chirped square wave signal whose frequency varies with time. The signal is transmitted to the laser via a cable to power the laser, causing the laser to generate a periodically varying laser signal. The output end of the laser is connected to the input end of a power amplifier via an optical fiber to amplify the energy of the periodic laser signal. The output end of the power amplifier is connected to the input end of a laser collimator via an optical fiber to collimate the direction of the laser. The amplified and collimated chirped modulated laser signal is irradiated onto the surface of a porcelain insulator. The porcelain insulator absorbs the laser energy and produces a solid photoacoustic effect, emitting an acoustic wave signal with the same frequency as the laser signal. The acoustic wave signal is collected by a signal collector and finally processed by a high-performance computer to obtain a spectrum of the acoustic wave signal. By analyzing the spectrum, it is determined whether there are defects in the porcelain insulator.

[0031] A nondestructive testing method for porcelain insulators based on chirp-modulated photoacoustic spectroscopy comprises the following steps:

[0032] S1: Use signal generator 1 to generate a chirped square wave signal whose frequency varies with time, such as Figure 2 As shown in the figure, the frequency range is 1kHz to 10kHz and the amplitude is 5V. It is transmitted to the input end of the laser 2 through the cable to power the laser, so that the laser generates a laser signal with a periodic change and an energy of 5W. Since the porcelain insulator contains a large amount of SiO2, SiO2 has an absorption coefficient of 3.3×10 at a wavelength of 780nm. -4 cm -1 / molec·cm -2 By adjusting the temperature of the laser, the output wavelength of the laser is adjusted to 780nm.

[0033] S2: The output end of laser 2 is connected to the input end of power amplifier 4 through optical fiber 3, amplifying the energy of the laser signal to 200W.

[0034] S3: The output end of the power amplifier 4 is connected to the input end of the laser collimator 6 through the optical fiber 5 to collimate the direction of the laser. After collimation, the divergence angle of the output laser is less than 0.1°.

[0035] S4: The chirped modulated laser signal after amplification and collimation is vertically irradiated onto the surface of the porcelain insulator 7. The SiO2 in the porcelain insulator 7 absorbs the laser energy and produces a solid photoacoustic effect, emitting an acoustic wave signal with the same frequency as the laser signal.

[0036] S5: The acoustic wave signal is collected by signal collector 8 and converted into an electrical signal. The signal is then transmitted via a cable to computer 9 for data processing. A spectrum of the acoustic wave signal is obtained. The presence of defects in the porcelain insulator is determined based on the characteristic frequencies in the spectrum. If a large peak is present in the frequency range of 1kHz to 2.5kHz or 8.5kHz to 10kHz, the porcelain insulator is considered defective and needs to be removed for further laboratory analysis.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. 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. A nondestructive testing device for porcelain insulators based on chirp-modulated photoacoustic spectroscopy, characterized in that: include: Signal generator (1); a laser (2) connected to the signal generator; a power amplifier (4) connected to the laser (2); a laser collimator (6) connected to the power amplifier (4); and A signal collector (8) collects acoustic signals and converts them into electrical signals, which are then transmitted to a computer (9) via a cable for data processing, thereby obtaining a spectrum of the acoustic signals and determining whether there are defects in the porcelain insulator based on the spectrum.

2. The nondestructive testing device for porcelain insulators based on chirp-modulated photoacoustic spectroscopy according to claim 1, characterized in that: The signal generator (1) is connected to the input end of the laser (2) via a cable to provide an excitation signal for the laser.

3. The nondestructive testing device for porcelain insulators based on chirp-modulated photoacoustic spectroscopy according to claim 1, characterized in that: The output end of the laser (2) is connected to the input end of a power amplifier (4) via an optical fiber (3) to enhance the power of the output laser.

4. The nondestructive testing device for porcelain insulators based on chirp-modulated photoacoustic spectroscopy according to claim 1, characterized in that: The output end of the power amplifier (4) is connected to the input end of the laser collimator (6) via an optical fiber (5) to collimate the direction of the output laser.

5. The nondestructive testing device for porcelain insulators based on chirp-modulated photoacoustic spectroscopy according to claim 1, characterized in that: The output end of the laser collimator (6) is perpendicular to the porcelain insulator (7), and the laser collimator (6) and the porcelain insulator (7) do not contact each other, so that the output laser is vertically irradiated on the surface of the porcelain insulator (7), and an acoustic wave signal is generated through the photoacoustic effect.

6. The nondestructive testing device for porcelain insulators based on chirp-modulated photoacoustic spectroscopy according to claim 1, characterized in that: The input end of the signal collector (8) is perpendicular to the porcelain insulator (7), and the signal collector (8) and the porcelain insulator (7) do not contact each other. The signal collector collects sound wave signals and converts the sound wave signals into electrical signals.

7. The nondestructive testing device for porcelain insulators based on chirp-modulated photoacoustic spectroscopy according to claim 1, characterized in that: The output end of the signal collector (8) is connected to a computer (9) via a cable, and the sound wave signal is transmitted to the computer (9) for data processing to obtain a spectrum diagram of the sound wave signal.

8. A nondestructive testing method for porcelain insulators based on chirp-modulated photoacoustic spectroscopy, characterized in that: The steps include: S1: A signal generator (1) is used to generate a chirped square wave signal whose frequency varies with time, and the chirped square wave signal is transmitted to the input end of the laser (2) through a cable to power the laser, so that the laser generates a laser signal with periodic variation; S2: The output end of the laser (2) is connected to the input end of the power amplifier (4) through an optical fiber (3) to amplify the energy of the laser signal; S3: The output end of the power amplifier (4) is connected to the input end of the laser collimator (6) through an optical fiber (5) to collimate the direction of the laser; S4: The chirped modulated laser signal after amplification and collimation is vertically irradiated onto the surface of the porcelain insulator (7). The porcelain insulator (7) absorbs the laser energy and produces a solid photoacoustic effect, emitting an acoustic wave signal with the same frequency as the laser signal; S5: The acoustic wave signal is collected by a signal collector (8) and converted into an electrical signal, which is then transmitted to a computer (9) via a cable for data processing to obtain a spectrum of the acoustic wave signal. The spectrum is then used to determine whether there are defects in the porcelain insulator.

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