Method and device for improving the sensitivity of vacuum detection of a vacuum switch

Abstract

The present disclosure discloses a method for improving the vacuum detection sensitivity of a vacuum switch, comprising the following steps: S100: uniformly applying a water-soluble metal nanoparticle reagent on the surface of a target material of a vacuum switch to be detected, and allowing the surface of the target material to form a metal nanoparticle coating after standing; S200: using a laser pulse to bombard the surface of the target material on which the metal nanoparticle coating is formed, so as to generate plasma at the surface of the target material; S300: collecting the plasma to obtain a plasma image, and performing spectral analysis on the plasma image to obtain a plasma spectrum; and S400: obtaining the vacuum degree of the vacuum switch to be detected based on the plasma spectrum. The present disclosure can effectively improve the degree of laser focusing, improve the stability of laser pulses, and reduce noise interference, thereby reducing the detection limit and improving the online detection sensitivity of the vacuum switch.

Description

Technical Field

[0001] This disclosure belongs to the field of laser diagnostic technology, specifically relating to a method and apparatus for improving the vacuum detection sensitivity of vacuum switches. Background Technology

[0002] Compared to air switches and oil switches, vacuum switches have advantages such as low failure rate, compact structure, strong breaking capacity, and simple maintenance, and are widely used in various fields such as power systems, coal mining, and petrochemicals. In actual use, with the increase of service life, the internal vacuum level of vacuum switches will gradually decrease due to factors such as aging of mechanical components and insulation deterioration. Therefore, it is necessary to test the vacuum level of vacuum switches. There are two methods for measuring the vacuum level of vacuum switches: online and offline. Offline testing technology is relatively mature, while most online testing technologies are still in the research stage. Currently, relatively mature vacuum level testing methods include: shielding cover color judgment method, arc light observation method, spark meter method, getter film method, arc voltage / current method, power frequency withstand voltage method, magnetron discharge method, emission current attenuation method, contact / immersion sensing method, and X-ray method, etc., but these methods require the equipment to be taken out of operation. Given the current lack of effective online detection methods for the vacuum level of vacuum interrupters, and to efficiently utilize resources, a technology for accurately detecting the vacuum level of vacuum switches during operation has been proposed. This technology is based on LIBS (Laser Induced Breakdown) spectroscopy. Through theoretical analysis of the laser plasma formation process, this technology explains that during plasma expansion, the initial plasma formed by the target material interacts with the ambient air, causing ambient air molecules to be excited and ionized, thus participating in the laser plasma formation process. Specifically, a portable laser generates pulsed laser light, which bombards the metal shielding shell through the glass outer shell of the vacuum interrupter. This generates plasma on the shielding surface with a nanosecond timescale and sub-millimeter spatial scale. The laser-induced plasma signal (including the radiation spectrum of atoms such as Cu, N, H, and O) is then measured to reflect the vacuum level. In real-time detection, the laser emitted by LIBS encounters noise interference during the induction of the target material, which affects the resulting spectral signal, resulting in lower sensitivity and higher detection limit. In some fields requiring higher precision, this technology cannot perform detection work well. Therefore, there is an urgent need for a technology that can improve the sensitivity of LIBS to overcome its inadequacy.

[0003] Currently, there are many techniques that can improve the sensitivity of LIBS, such as using dual-pulse LIBS technology, which increases the ablation rate and atmospheric effect on the sample surface, and absorbs the second laser pulse in the expanding plasma to reheat the plasma generated by the first laser pulse; another technique is to use a ring magnet to enhance the detection sensitivity, the strength enhancement effect of the ring magnet is attributed to the simultaneous existence of spatial and magnetic confinement, which can increase the temperature and electron density of the plasma; or external electric or magnetic fields, etc. However, these techniques are all achieved by external energy sources or tunable lasers, which are not suitable for the closed environment of vacuum switch arc-extinguishing chambers. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this disclosure is to provide a method for improving the vacuum detection sensitivity of vacuum switches. This method can effectively improve the laser focusing degree, enhance laser pulse stability, and reduce noise interference, thereby lowering the detection limit and improving the online vacuum detection sensitivity of vacuum switches.

[0005] To achieve the above objectives, this disclosure provides the following technical solutions:

[0006] A method for improving the vacuum detection sensitivity of a vacuum switch includes the following steps:

[0007] S100: Apply water-soluble metal nanoparticle reagent evenly to the target surface of the vacuum switch to be tested, let it stand, and allow the metal nanoparticle coating to form on the target surface.

[0008] S200: Using laser pulses to bombard the surface of a target material to form a metal nanoparticle coating, thereby generating plasma at the surface of the target material.

[0009] S300: Collects plasma to obtain plasma images, performs spectral analysis on the plasma images to obtain plasma spectra;

[0010] S400: Obtain the vacuum level of the vacuum switch under test based on plasma spectra.

[0011] Preferably, the water-soluble metal nanoparticle reagent includes water-soluble silver nanocolloid reagent and water-soluble gold nanocolloid reagent.

[0012] Preferably, the concentration of the metal nanoparticle reagent is from 0.01 mg / ml to 0.1 mg / ml.

[0013] Preferably, the radius of the metal nanoparticles in the metal nanoparticle reagent is 10 nm.

[0014] This disclosure also provides a device for improving the vacuum detection sensitivity of a vacuum switch, comprising:

[0015] The laser emitting module is used to emit a laser to irradiate the target material with a metal nanoparticle coating formed inside the vacuum switch under test, so as to generate plasma on the surface of the target material.

[0016] The acquisition module is used to acquire plasma and obtain plasma images;

[0017] The analysis module is used to perform spectral analysis on plasma images to obtain plasma spectra;

[0018] The detection module is used to detect the plasma spectrum in order to obtain the vacuum level of the vacuum switch under test.

[0019] Preferably, the laser emitting module includes a laser emitter, and a focusing lens and a dichroic mirror are arranged in the optical path of the laser emitter.

[0020] Preferably, the acquisition module includes an ICCD camera.

[0021] Preferably, the analysis module includes a spectrometer.

[0022] Preferably, the detection module includes a host computer.

[0023] Preferably, the acquisition module further includes a digital delay pulse generator.

[0024] Compared with the prior art, the beneficial effects of this disclosure are as follows:

[0025] 1. By coating the target material inside the vacuum switch with metal nanoparticle reagents, the signal-to-noise ratio of laser-induced plasma imaging and spectral signals can be improved, the enhancement effect is achieved, and the repeatability is high. This avoids the signal spectral lines being submerged by noise or being indistinguishable from noise, and solves the problems of low sensitivity, high detection limit, and high noise interference of traditional LIBS laser pulses.

[0026] 2. Using metal nanoparticle colloidal reagents as a coating simplifies the measurement process, making it safe and reliable, and achieving more precise detection results. In some fields requiring higher precision, laser-induced breakdown spectroscopy (LEBS) cannot perform the detection work well. In such cases, NELIBS is needed to improve the signal intensity, typically enhancing it by 1-2 orders of magnitude. Attached Figure Description

[0027] Figure 1 A flowchart illustrating a method for improving the vacuum detection sensitivity of a vacuum switch, as provided in another embodiment of this disclosure;

[0028] Figure 2(a) shows the spectral signals obtained at a reagent concentration of 0.1 mg / ml and without the reagent applied.

[0029] Figure 2(b) shows the spectral signals obtained at a reagent concentration of 0.05 mg / ml and without the reagent applied.

[0030] Figure 2(c) shows the spectral signals obtained at a reagent concentration of 0.01 mg / ml and without reagent application;

[0031] Figure 3 A schematic diagram of a device structure for improving the vacuum detection sensitivity of a vacuum switch, provided as an embodiment of this disclosure;

[0032] The annotations in the attached figures are explained as follows:

[0033] 1. Laser emitter; 2. Focusing lens; 3. Dichroic mirror; 4. Vacuum interrupter; 5. Spectrometer; 6. ICCD camera; 7. Delayed pulse emitter. Detailed Implementation

[0034] The following will refer to the appendix. Figures 1 to 3 Specific embodiments of this disclosure are described in detail. While specific embodiments of this disclosure are shown in the accompanying drawings, it should be understood that this disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art.

[0035] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions are preferred embodiments for carrying out this disclosure; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of this disclosure. The scope of protection of this disclosure is determined by the appended claims.

[0036] To facilitate understanding of the embodiments of this disclosure, further explanations and descriptions will be provided below with reference to the accompanying drawings and specific embodiments. The accompanying drawings do not constitute a limitation on the embodiments of this disclosure.

[0037] In one embodiment, such as Figure 1 As shown, this disclosure provides a method for improving the vacuum detection sensitivity of a vacuum switch, comprising the following steps:

[0038] S100: A pure copper plate was used as the experimental target material for the vacuum switch to be tested. Silver nanoparticle reagent with a concentration of 0.01 mg / ml and a particle radius of 10 nm was dropped onto the target material. Then, it was evenly coated into a uniform rectangle with a glass rod. After standing and drying, a gold nanoparticle coating was formed on the surface of the target material.

[0039] S200: Using laser pulses to bombard the surface of a target material to form a gold nanoparticle coating, thereby generating plasma at the surface of the target material.

[0040] S300: Acquires plasma to obtain plasma images, performs spectral analysis on the plasma images to obtain plasma spectral signals;

[0041] S400: Obtains the vacuum level of the vacuum switch under test based on plasma spectral signals.

[0042] In another embodiment, this disclosure also provides a method for improving the vacuum detection sensitivity of a vacuum switch. Specifically, in this embodiment, the concentration of the silver nanoparticle reagent is 0.05 mg / ml. For a comparison of different concentrations, please refer to the following text.

[0043] In another embodiment, this disclosure also provides a method for improving the vacuum detection sensitivity of a vacuum switch, except that the concentration of the silver nanoparticle reagent in this embodiment is 0.1 mg / ml.

[0044] In another embodiment, this disclosure also provides a method for improving the vacuum detection sensitivity of a vacuum switch. The difference is that in this embodiment, the silver nanoparticle reagent is replaced with a gold nanoparticle reagent, and the concentration of the gold nanoparticle reagent is still set to 0.01 mg / ml to 0.1 mg / ml.

[0045] The above embodiments constitute the complete technical solution of this disclosure. In the solutions shown in the above embodiments, since gold or silver nanoparticles are uniformly distributed on the target surface, on the one hand, the target surface is rougher, which can reduce the breakdown threshold of the laser pulse; on the other hand, the interaction between the laser pulse and the target is mainly carried out through the gold or silver nanoparticles. When the laser bombards the target, it first contacts and couples with the nanoparticles. Under the action of the laser electromagnetic field, the coherent oscillation of electrons in the nanoparticles generates dipoles and excites the electromagnetic field, which in turn can form localized surface plasmons (LSPs) on the target surface. The LSPs of adjacent nanoparticles couple with each other and generate a stronger electromagnetic field in the gaps between particles, forming "hot spots". The strong electric field of the "hot spots" is the cause of field-induced electron emission. Furthermore, since the localized surface plasmons of adjacent nanoparticles couple with each other, the electromagnetic fields between adjacent particles overlap, thereby generating a stronger oscillating electromagnetic field in the gaps between nanoparticles. Under the action of this oscillating electromagnetic field, the ionization mechanism changes from multiphoton ionization to field-induced electron emission. The strong electric field causes electron emission to occur instantaneously, ionizing and generating plasma before the nanoparticles completely melt. In this way, the spontaneous emission of the plasma is imaged onto the end face of the collection optical path and transmitted to the ICCD camera via the transmission optical path, thereby enhancing the signal-to-noise ratio of the plasma signal and effectively improving the detection limit.

[0046] In one specific embodiment, laser bombardment experiments were conducted on targets coated with different concentrations of gold nanoparticle reagents or silver nanoparticle reagents and targets without such coatings to illustrate the technical effects of this disclosure.

[0047] The experiment used a 1064nm Q-switch Nd:YAG laser emitter, with a signal generator producing pulse signals to control the laser pulses. During the experiment, a copper target plate was placed in a vacuum chamber with a quartz window. A 150mm focal length convex lens was used to focus the laser, concentrating energy at the target impact point. A 90mm convex lens was used as the collecting optical path. A dichroic mirror separated the laser from the induced plasma, and the spectral signal of the plasma was analyzed using a spectrometer and an ICCD camera. For low-pressure experiments, a mechanical pump was used to evacuate the vacuum chamber, and a thermionic vacuum gauge was used to measure the internal pressure in real time. A three-dimensional stepper motor moved the copper plate within the vacuum chamber.

[0048] At the start of the experiment, the vacuum chamber was sealed first, and then the first-stage pump was used to evacuate the air, achieving a vacuum level of 10. -3After Pa, a signal generator produces a pulse signal to trigger the laser, inducing plasma which is collected by the optical path system to obtain the corresponding spectrum. Since the time required from the laser emission to its interaction with the copper plate is extremely short, its effect on the delay time can be ignored. The spectrometer receives the optical signal and transmits it to a computer, where the spectral waveform is displayed using AVANTES software. The plasma image captured by the ICCD camera is analyzed using Andor and Matlab software to obtain the corresponding intensity data.

[0049] Based on the above experiments, the following results can be obtained for silver nanoparticle reagents: Figures 2(a) to 2(c) The plasma spectral signal diagrams shown are as follows: Figure 2(a) shows the spectral signal diagrams obtained with a reagent concentration of 0.1 mg / ml and without reagent application; Figure 2(b) shows the spectral signal diagrams obtained with a reagent concentration of 0.05 mg / ml and without reagent application; Figure 2(c) shows the spectral signal diagrams obtained with a reagent concentration of 0.01 mg / ml and without reagent application. Figures 2(a) to 2(c) In Figure 2(a), the plasma spectral signal intensity after applying the reagent was significantly greater than that without the reagent. Specifically, in Figure 2(a), the plasma spectral signal intensity at 510.5 nm was approximately 36,000 a.u.; in Figure 2(b), it was approximately 33,000 a.u.; and in Figure 2(c), it was approximately 28,000 a.u. This indicates that the plasma signal intensity decreased slightly as the nanoparticle concentration decreased. Experiments verified that 0.1 mg / ml was the optimal reagent concentration for silver nanoparticles, as this concentration resulted in the highest plasma spectral signal intensity. Furthermore, experiments confirmed that concentrations of silver nanoparticles ranging from 0.01 mg / ml to 0.1 mg / ml met practical requirements, and the concentrations of gold nanoparticles could also be selected from 0.01 mg / ml to 0.1 mg / ml. In this disclosure, the metal nanoparticle coating improves the detection sensitivity without interfering with the plasma spectrum. Therefore, this disclosure uses existing technology that obtains the vacuum degree of the vacuum switch under test based on the plasma spectrum to obtain the detection result of the vacuum degree of the vacuum switch with higher detection sensitivity.

[0050] In another embodiment, this disclosure also provides an apparatus for improving the vacuum detection sensitivity of a vacuum switch, comprising:

[0051] The laser emitting module is used to emit lasers to irradiate the target material with a metal nanoparticle coating formed inside the vacuum interrupter chamber 4, so as to generate plasma on the surface of the target material.

[0052] The acquisition module is used to acquire plasma and obtain plasma images;

[0053] The analysis module is used to perform spectral analysis on plasma images to obtain plasma spectra;

[0054] The detection module is used to detect the plasma spectrum in order to obtain the vacuum level of the vacuum switch under test.

[0055] The above embodiments constitute the complete technical solution of this disclosure. This embodiment, by coating the target material within the vacuum switch with metal nanoparticle reagents, enables higher signal-to-noise ratios in laser-induced plasma imaging and spectral signals, thereby reducing the detection limit of traditional LIBS laser pulses and improving the online vacuum detection sensitivity of the vacuum switch.

[0056] In another embodiment, the laser emitting module includes a laser emitter 1, and a focusing lens 2 and a dichroic mirror 3 are disposed in the optical path of the laser emitter 1.

[0057] In this embodiment, the laser emitted by the laser emitter is focused by a focusing lens and reflected by a dichroic mirror into the transmission optical path, and further irradiates the target material coated with metal nanoparticles inside the vacuum switch under test along the transmission optical path, thereby inducing the generation of plasma.

[0058] In another embodiment, the acquisition module includes an ICCD camera 6.

[0059] In another embodiment, the analysis module includes a spectrometer 5.

[0060] In another embodiment, the detection module includes a host computer.

[0061] In another embodiment, the acquisition module further includes a digital delay pulse generator 7.

[0062] The applicant has provided a detailed description of the embodiments of this disclosure in conjunction with the accompanying drawings. However, those skilled in the art should understand that the above embodiments are merely preferred examples of this disclosure and are not limited to the specific embodiments described above. The detailed description is intended to help readers better understand the spirit of this disclosure and is not intended to limit the scope of protection of this disclosure. On the contrary, any improvements or modifications made based on the inventive spirit of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A method for improving the vacuum detection sensitivity of a vacuum switch, comprising the following steps: S100: Apply water-soluble metal nanoparticle reagent evenly to the target surface of the vacuum switch to be tested, let it stand, and allow the metal nanoparticle coating to form on the target surface. S200: Using laser pulses to bombard the surface of a target material to form a metal nanoparticle coating, thereby generating plasma at the surface of the target material. S300: Collects plasma to obtain plasma images, performs spectral analysis on the plasma images to obtain plasma spectra; S400: Obtain the vacuum level of the vacuum switch under test based on plasma spectra.

2. The method according to claim 1, wherein, The water-soluble metal nanoparticle reagent includes any one of the following: water-soluble silver nanocolloid reagent and water-soluble gold nanocolloid reagent.

3. The method according to claim 1, wherein, The concentration of the metal nanoparticle reagent is from 0.01 mg / ml to 0.1 mg / ml.

4. The method according to claim 1, wherein, The metal nanoparticles in the aforementioned metal nanoparticle reagent have a radius of 10 nm.

5. A device for improving the vacuum detection sensitivity of a vacuum switch, comprising: The laser emitting module is used to emit a laser to irradiate the target material with a metal nanoparticle coating formed inside the vacuum switch under test, so as to generate plasma on the surface of the target material. The acquisition module is used to acquire plasma and obtain plasma images; The analysis module is used to perform spectral analysis on plasma images to obtain plasma spectra; The detection module is used to detect the plasma spectrum in order to obtain the vacuum level of the vacuum switch under test.

6. The apparatus according to claim 5, wherein, The laser emitting module includes a laser emitter, and a focusing lens and a dichroic mirror are arranged in the optical path of the laser emitter.

7. The apparatus according to claim 5, wherein, The acquisition module includes an ICCD camera.

8. The apparatus according to claim 5, wherein, The analysis module includes a spectrometer.

9. The apparatus according to claim 5, wherein, The detection module includes a host computer.

10. The apparatus according to claim 5, wherein, The acquisition module also includes a digital delay pulse generator.

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