SF6 decomposition product sensor and preparation method thereof

Abstract

The present application relates to an SF6 decomposition product sensor and a preparation method thereof. The SF6 decomposition product sensor includes a first electrode, a second electrode, and a third electrode stacked in sequence; a micrometer column array is provided on the surface of the first electrode close to the second electrode, and the first electrode is provided with at least one through hole; a micrometer column array is provided on the surface of the second electrode close to the first electrode, and the second electrode is provided with at least one through hole; a micrometer column array is provided on the surface of the third electrode close to the second electrode, and the third electrode is provided with a groove; wherein the material of each micrometer column in the micrometer column array on each electrode is a composite of SU-8 photoresist and silicon material; a first support member is provided between the first electrode and the second electrode to isolate the first electrode and the second electrode; a second support member is provided between the second electrode and the third electrode to isolate the second electrode and the third electrode. The SF6 decomposition product sensor of this solution has high sensitivity.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to an SF6 decomposition product sensor and a preparation method thereof. Background Art

[0002] The safe and reliable operation of power systems is paramount, and the safe operating status of high-voltage equipment, as a crucial component of these systems, naturally attracts considerable attention. SF6 (sulfur hexafluoride) gas, due to its significantly greater arc extinguishing capability than air and its high voltage breakdown withstand capability, is widely used in high-voltage equipment such as GIS (gas-insulated metal-enclosed switchgear), high-voltage transformers, high-voltage circuit breakers, and gas-insulated pipeline transmission lines. To ensure the safety and stability of high-voltage equipment, SF6 gas leak detection, moisture content testing, and SF6 decomposition product testing are essential in both preventive and acceptance testing of high-voltage equipment. SF6 decomposition product detection, in particular, has been widely used in the power industry due to its low sensitivity to on-site electromagnetic interference and ability to accurately locate defects or gas chamber faults.

[0003] Currently, common methods for detecting SF6 decomposition products include chemical analysis, gas detection tubes, gas chromatography, spectroscopy, and sensor detection. Sensor detection has become a popular research topic due to its simplicity and low detection limits. However, existing SF6 decomposition product sensors have low sensitivity and need further improvement. Summary of the Invention

[0004] Based on this, it is necessary to provide a SF6 decomposition product sensor with higher sensitivity and a preparation method thereof to address the above technical problems.

[0005] In a first aspect, the present application provides an SF6 decomposition product sensor, which includes a first electrode, a second electrode and a third electrode stacked in sequence; a micron column array is provided on the surface of the first electrode close to the second electrode, and at least one through hole is provided on the first electrode; a micron column array is provided on the surface of the second electrode close to the first electrode, and at least one through hole is provided on the second electrode; a micron column array is provided on the surface of the third electrode close to the second electrode, and a groove is provided on the third electrode; wherein the material of each micron column in the micron column array on each electrode is a composite of SU-8 photoresist and silicon material; a first support member is provided between the first electrode and the second electrode to isolate the first electrode and the second electrode; a second support member is provided between the second electrode and the third electrode to isolate the second electrode and the third electrode.

[0006] In one embodiment, the orthographic projection of the second electrode on the third electrode covers the orthographic projection of the first electrode on the third electrode; and the orthographic projection of the second electrode on the third electrode covers at least a portion of the third electrode.

[0007] In one embodiment, the micron column array on the third electrode is arranged around the groove.

[0008] In one embodiment, the SF6 decomposition product sensor further includes a battery; the first electrode is connected to the negative electrode of the battery; and the second electrode is connected to the positive electrode of the battery.

[0009] In one embodiment, the SF6 decomposition product sensor further includes a current detector; a first end of the current detector is connected to the third electrode, and a second end of the current detector is connected to the second electrode.

[0010] In one embodiment, the SF6 decomposition product sensor further includes a housing, which is used to encapsulate the first electrode, the second electrode, and the third electrode.

[0011] In one embodiment, the SF6 decomposition product sensor also includes a pointer arranged on the shell, a concentration etching line arranged on the shell, and a driver and a single-chip microcomputer arranged in the inner cavity of the shell; the single-chip microcomputer is connected to the current detector; one end of the driver is connected to the single-chip microcomputer, and the other end of the driver is connected to the pointer.

[0012] In one embodiment, the SF6 decomposition product sensor further includes a warning indicator light, which is connected to the single chip microcomputer.

[0013] In one embodiment, the SF6 decomposition product sensor further includes a charging interface for connecting to an external power source to charge the battery.

[0014] In a second aspect, the present application also provides a method for preparing an SF6 decomposition product sensor, the preparation method comprising: obtaining a first electrode and a second electrode provided with at least one through hole, and obtaining a third electrode provided with a groove; wherein the materials of the first electrode, the second electrode and the third electrode are all silicon materials; using a deep reactive ion etching method based on an alternating reciprocating process to prepare micron column arrays on the first electrode, the second electrode and the third electrode, respectively, wherein, for each electrode, in the process of preparing the micron column array, SU-8 photoresist is applied to the surface of the targeted electrode by a spin coating process to form an SU-8 single layer, and the SU-8 single layer is printed by two-photon molding technology. After printing, the uncured SU-8 photoresist is dissolved with an ethanol solvent to obtain a micron column array on the surface of the targeted electrode; a glass sheet is bonded between the first electrode and the second electrode to form a first support member, and a glass sheet is bonded between the second electrode and the third electrode to form a second support member.

[0015] The SF6 decomposition product sensor includes a first electrode, a second electrode, and a third electrode stacked in sequence. A micron-pillar array is provided on the surface of the first electrode near the second electrode, and the first electrode is provided with at least one through-hole. A micron-pillar array is provided on the surface of the second electrode near the first electrode, and the second electrode is provided with at least one through-hole. A micron-pillar array is provided on the surface of the third electrode near the second electrode, and the third electrode is provided with a groove. The micron-pillars in the micron-pillar arrays on each electrode are made of a composite of SU-8 photoresist and silicon. A first support is provided between the first and second electrodes to isolate the first and second electrodes. A second support is provided between the second and third electrodes to isolate the second and third electrodes. Compared to a micron-pillar array made of silicon alone, the micron-pillar array made of the composite of SU-8 photoresist and silicon can further enhance the electric field effect and promote the occurrence of field emission, thereby improving the sensitivity and accuracy of the SF6 decomposition product sensor in detecting SF6 decomposition products. In addition, SU-8 photoresist has flexible properties. Therefore, when the SF6 decomposition product sensor is subjected to vibration, the micron columns in the micron column array are not easily broken, thereby avoiding short circuits of the electrodes and extending the life of the SF6 decomposition product sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments of the present application or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 Schematic diagram of a SF6 decomposition product sensor in one embodiment;

[0018] Figure 2 FIG1 is a top view of three electrodes in an SF6 decomposition product sensor according to an embodiment;

[0019] Figure 3 Schematic diagram of a process for preparing a sensor for SF6 decomposition products according to one embodiment;

[0020] Figure 4 FIG1 is a graph showing the response characteristics of an SF6 decomposition product sensor to SO2 under DC excitation in one embodiment;

[0021] Figure 5 FIG1 is a graph showing the response characteristics of an SF6 decomposition product sensor to H2S under DC excitation in one embodiment;

[0022] Figure 6FIG1 is a graph showing the response characteristics of an SF6 decomposition product sensor to CO under DC excitation in one embodiment;

[0023] Figure 7 FIG1 is a graph showing the response characteristics of an SF6 decomposition product sensor to SO2 under pulse excitation in one embodiment;

[0024] Figure 8 FIG1 is a graph showing the response characteristics of an SF6 decomposition product sensor to H2S under pulse excitation in one embodiment;

[0025] Figure 9 FIG1 is a graph showing the response characteristics of an SF6 decomposition product sensor to CO under pulse excitation in one embodiment;

[0026] Figure 10 FIG1 is a graph showing the response characteristics of the SF6 decomposition product sensor to SO2 under pulse excitation in another embodiment;

[0027] Figure 11 FIG1 is a graph showing the response characteristics of the SF6 decomposition product sensor to H2S under pulse excitation in another embodiment;

[0028] Figure 12 FIG. 4 is a graph showing the response characteristics of the SF6 decomposition product sensor to CO under pulse excitation in another embodiment. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0030] The safe and reliable operation of power systems is paramount, and the safe operating status of high-voltage equipment, as a crucial component of these systems, naturally attracts considerable attention. SF6 (sulfur hexafluoride) gas, due to its significantly greater arc extinguishing capability than air and its high voltage breakdown withstand capability, is widely used in high-voltage equipment such as GIS equipment, high-voltage transformers, high-voltage circuit breakers, and gas-insulated transmission lines. To ensure the safety and stability of high-voltage equipment, SF6 gas leak detection, moisture content testing, and SF6 decomposition product testing are essential in both preventive and acceptance testing of high-voltage equipment. SF6 decomposition product detection, among other methods, offers advantages such as minimal on-site electromagnetic interference and the ability to accurately locate defects or gas chamber faults, making it widely used in the power industry.

[0031] Common methods for detecting SF6 decomposition products include chemical analysis, gas detection tubes, gas chromatography, and sensor detection. Chemical analysis is highly susceptible to interference in real-world environments, which can affect measurement results. It is also time-consuming and involves complex experimental procedures. Gas detection tubes are susceptible to temperature and humidity, have a short shelf life, and exhibit low measurement accuracy, so they are currently used only as auxiliary measurements in the field. Gas chromatography columns can only accurately analyze detection in a laboratory setting and are unsuitable for online monitoring. Sensor detection has become a popular research topic due to its ease of use and low detection limits.

[0032] Gas chromatography is used to detect the decomposition products of SF6 mixed gas, and up to 16 decomposition products can be detected in one injection. However, the test results of different units vary greatly, the detection accuracy is low, and it is difficult to compare.

[0033] Infrared spectroscopy can detect a variety of SF6 decomposition products, with a minimum detection limit of ppm (concentration unit, indicating the mass of the solute as a percentage of the total solution mass) level. The detection time is short, and continuous online monitoring can be achieved. However, the absorption peaks of SF6 and some of its decomposition products overlap, making it difficult to identify characteristic absorption components. Standard gas must be used to obtain a reference spectrum to calibrate the test results. The SF6 decomposition product components have low content and weak absorption, and the relative change between the incident spectrum and the absorbed spectrum is small, resulting in low detection sensitivity.

[0034] Based on ultraviolet spectrum detection technology, the SO2 (sulfur dioxide) concentration is detected by simulating GIS partial discharge. The detection range is 0ppm-12ppm, and the minimum detection limit is 1ppm. It has high detection accuracy, but has the disadvantage of a small detection range.

[0035] Based on the principle of photoacoustic spectroscopy, fault derivatives in SF6 equipment can be discovered by experimentally analyzing transformer oil and gas data at different voltages and times. However, this method has low accuracy and detection precision and can only be used as one of the bases for fault judgment.

[0036] Gas sensors based on various nanomaterials detect SF6 decomposition products. The results show that the resistance of the gas sensor decreases with discharge time, which can reflect the overall situation of the decomposition components, but cannot detect the exact concentration of each SF6 decomposition component.

[0037] Based on nickel chloride-doped multi-walled carbon nanotube sensors, the sensor's gas-sensitive responses to SF6 simulated discharge products, 20ppm SOF2 (sulfur-based halide) and 500ppm SO2 gases were experimentally studied. It was found that the sensor has similar response characteristics to SOF2 and SO2 and cannot effectively distinguish between the two gases; its gas sensitivity to SO2 is poor and its sensitivity is low.

[0038] Based on the hydroxyl-modified single-walled carbon nanotube gas sensor, the experiment detected SOF2, SO2 and CF4 (carbon tetrafluoride) gases at two concentration points of 250ppm and 500ppm, and found that the sensor responded to gases of different concentrations; gas sensing experiments were also carried out on SO2 from 0 to 500ppm, and the sensor resistance change rate and SO2 concentration change approximately satisfied a linear relationship, but the sensor's recovery process was relatively slow.

[0039] A TiO2 nanotube sensor developed using a Pt (platinum)-doped TiO2 (titanium dioxide) nanotube array fabricated by electrochemical pulse deposition was used as the sensitive material. The sensor demonstrated good response curves to SO2 and SOF2 gases at concentrations between 25ppm and 100ppm. However, after a period of use, the sensor requires UV irradiation for desorption, otherwise the initial resistance and sensitivity will be affected, thereby affecting the sensor's measurement accuracy.

[0040] A three-electrode carbon nanotube (CNT) ionization sensor was used to study other fault-signaling gases in transformers. Response curves for H2S (hydrogen sulfide) and C2H2 (acetylene) were obtained from 0 ppm to 400 ppm. While the response curves were good under single-value conditions, the sensor's structural design could easily damage the cathode due to charged particle bombardment. This damage to the cathode causes a drop in the sensor's collector current, making it impossible to detect gases. Furthermore, operating in the discharge region of the sensor generates significant heat, which damages the CNTs and significantly reduces their lifespan. The CNT ionization sensor detects SO2 or SOF2, decomposition products of SF6, with a detection range of 0 ppm to 110 ppm and good single-value sensitivity. However, the sensor has a short lifespan and is easily damaged.

[0041] A new sensor fabricated using a gold nanopore structure exhibits high sensitivity and good response characteristics for gas detection, but suffers from significant hysteresis error. Using radio frequency as an excitation source, the sensor's response to H₂S was investigated, resulting in a well-defined single-value response curve, which facilitates accurate H₂S detection. However, this sensor requires high power consumption and has a limited detection range. In this study, a single-sided micronized pillar electrode was employed, which enhances sensor-gas interaction and improves detection sensitivity and selectivity. Furthermore, using 12M radio frequency excitation for the detection of CO (carbon monoxide) and CH₄, the minimum detection limits were 25 ppm and 10 ppb, respectively, with maximum sensitivities of -8.78×10⁻² nA / ppm and -3.78×10⁻² nA / ppm, respectively. However, the sensor exhibited poor hysteresis under radio frequency excitation, making reproducible gas measurements difficult and consuming high power.

[0042] In summary, existing sensors for detecting the concentrations of CO, SO2, and H2S gases in SF6 decomposition products suffer from shortcomings such as low sensitivity, low detection accuracy, and a narrow measuring range. Therefore, it is necessary to propose effective technical solutions to address these technical issues. The following detailed examples illustrate the technical solutions of this application and how they address the aforementioned technical issues. The following specific examples may be combined with one another, and identical or similar concepts or processes may not be described in detail in certain examples. The following examples of this application are described in conjunction with the accompanying drawings.

[0043] In one embodiment, Figure 1 As shown, the present application provides a three-dimensional schematic diagram of an SF6 decomposition product sensor, which includes: a first electrode 101, a second electrode 102, and a third electrode 103 stacked in sequence; a micron column array KP is provided on the surface of the first electrode 101 on the side close to the second electrode 102, and at least one through hole LP is provided on the first electrode 101; a micron column array KP is provided on the surface of the second electrode 102 on the side close to the first electrode 101, and at least one through hole LP is provided on the second electrode 102 (due to the obstruction of the micron column array KP in the figure, the second electrode 10 2 is covered); a micrometer column array KP is provided on the surface of the third electrode 103 on the side close to the second electrode 102, and a groove MP is provided on the third electrode 103; wherein the material of each micrometer column in the micrometer column array KP on each electrode is a composite of SU-8 photoresist and silicon material; a first support member 104 is provided between the first electrode 101 and the second electrode 102 to isolate the first electrode 101 and the second electrode 102; a second support member 105 is provided between the second electrode 102 and the third electrode 103 to isolate the second electrode 102 and the third electrode 103.

[0044] Among them, the materials of the first electrode 101, the second electrode 102 and the third electrode 103 can all be silicon materials, and silicon materials are metal nanoporous materials. They not only have a large internal surface area, high porosity and relatively uniform nanopores, but also have the excellent properties of metal materials such as corrosion resistance, high conductivity, high thermal conductivity, and fatigue resistance. Therefore, this application uses metal nanoporous materials to replace carbon nanotube films in traditional sensors, which has better performance.

[0045] The first electrode 101 can be called a cathode, the second electrode can be called an extraction electrode, and the third electrode can be called a collector. The through hole LP on the first electrode 101 and the through hole LP on the second electrode 102 can both be circular, and the groove MP on the third electrode 103 can be rectangular.

[0046] The diameter of each through-hole LP on the first electrode 101 is greater than or equal to 0.6 mm and less than or equal to 3.6 mm. The diameter of each through-hole LP on the second electrode 102 is greater than or equal to 1 mm and less than or equal to 5 mm. The length of the groove MP in the third electrode 103 in the first direction x and the second direction y are both greater than or equal to 1 mm and less than or equal to 8 mm. The length of the groove MP in the third direction z (i.e., the depth of the groove MP) is greater than 100 μm and less than or equal to 240 μm.

[0047] The number of through holes LP on the first electrode 101 is greater than or equal to 1 and less than or equal to 20. The number of through holes LP on the second electrode 102 is greater than or equal to 1 and less than or equal to 20. The number of grooves MP on the third electrode 103 is greater than or equal to 1 and less than or equal to 20.

[0048] When the aperture of each through hole LP on the first electrode 101 is greater than or equal to 0.6 mm and less than or equal to 3.6 mm, the ratio of the distance between the first electrode 101 and the second electrode 102 to the aperture of the through hole LP on the first electrode 101 is greater than or equal to 1 / 60 and less than or equal to 1 / 8.

[0049] When the aperture of each through hole LP on the second electrode 102 is greater than or equal to 1 mm and less than or equal to 5 mm, the ratio of the spacing between the first electrode 101 and the second electrode 102 to the aperture of the through hole LP on the second electrode 102 is greater than or equal to 9 / 1000 and less than or equal to 2 / 25.

[0050] When the length and width of the groove MP on the third electrode 103 are both greater than or equal to 1 mm and less than or equal to 8 mm, and the depth of the groove MP is greater than 100 μm and less than or equal to 240 μm, the ratio of the distance between the second electrode 102 and the third electrode 103 to the depth of the groove MP is greater than or equal to 3 / 16 and less than or equal to 4 / 5.

[0051] like Figure 2 As shown, a top view of three electrodes in an SF6 decomposition product sensor is provided. Figure 2 Figure (a) is a top view of the first electrode 101. Figure 2 Figure (b) is a top view of the second electrode 102. Figure 2 Figure (c) is a top view of the third electrode 103 .

[0052] In Figure (a), the spacing between the two through holes LP on the first electrode 101 is 0.9 mm, and the diameter of each through hole is 0.3 mm; the length of the micron pillar array KP on the first electrode 101 in the first direction x is 3 mm, and the length in the second direction y is 5 mm; the length of the first electrode 101 in the first direction x is 8 mm, and the length in the second direction y is 7 mm. Other dimensions marked in Figure (a) can be found in the figure and are not described in detail here.

[0053] In Figure (b), the spacing between the two through-holes LP on the second electrode 102 is 0.9 mm, and the diameter of each through-hole is 0.3 mm. The length of the micropillar array KP on the second electrode 102 in the first direction x is 3 mm, and its length in the second direction y is 5 mm. The length of the second electrode 102 in the first direction x is 9 mm, and its length in the second direction y is 7 mm. Other dimensions marked in Figure (b) refer to the reference figure and are not detailed here. It should be noted that the length of the white area in Figure (b) in the first direction x is 1 mm, which is the distance from the edge of the second electrode 102 to the first support member 104.

[0054] In Figure (c), the length of the groove MP on the third electrode 103 in the first direction x is 2.4 mm, and its length in the second direction y is 2 mm. The length of the micropillar array KP on the third electrode 103 in the first direction x is 3 mm, and its length in the second direction y is 5 mm. The length of the third electrode 103 in the first direction x is 10 mm, and its length in the second direction y is 7 mm. Other dimensions marked in Figure (c) refer to the reference figure and are not detailed here. It should be noted that the length of the white area in Figure (c) in the first direction x is 2 mm, which is the distance from the edge of the third electrode 103 to the second support member 105.

[0055] Each micron-pillar in the KP micron-pillar array is made of a composite of SU-8 photoresist and silicon. SU-8 photoresist offers excellent corrosion resistance and thermal stability, and combined with silicon, it enhances field ionization and field-induced electron emission of decomposed products. SU-8 photoresist is also flexible, making it less susceptible to breakage in the presence of vibration.

[0056] The diameter of each micro-pillar in the micro-pillar array KP is greater than or equal to 5 μm and less than or equal to 10 μm, the height is greater than or equal to 10 μm and less than or equal to 60 μm, and the interval between two adjacent micro-pillars is greater than or equal to 10 μm and less than or equal to 30 μm.

[0057] The first support member 104 and the second support member 105 are both made of insulating materials. For example, the first support member 104 and the second support member 105 can both be made of glass.

[0058] The operating principle of the SF6 decomposition product sensor described above is as follows: Under active conditions, the SF6 decomposition product sensor is exposed to an electric field. The through-holes LP on the first electrode 101 allow SF6 decomposition products (such as SO2, H2S, and CO) to enter. SF6 decomposition products are ionized between the first electrode 101 and the second electrode 102. The micron-pillar tip structure offers a unique advantage: its tip shape enhances the electric field and enables field emission at a lower electric field. Compared to traditional planar electrode structures, this reduces the operating voltage, enabling the SF6 decomposition product sensor to achieve electron emission at a lower electric field. Furthermore, the multiple tips provide a larger emission surface area. By increasing the number and layout of the tips, the total emission surface area is effectively increased, thereby improving the emission current density and enhancing the overall current output capability. Accelerated by the electric field, the escaping electrons collide with SF6 decomposition product molecules, triggering more ionization reactions and generating a large number of positive ions. During this stage, the electron energy continuously increases. The positive ions are confined by the electric field and migrate toward the third electrode 103. At this point, the current at the third electrode 103 is measured to determine the SF6 decomposition product concentration.

[0059] The above-mentioned SF6 decomposition product sensor includes: a first electrode 101, a second electrode 102, and a third electrode 103, which are stacked in sequence; a micron-pillar array KP is provided on the surface of the first electrode 101 on the side close to the second electrode 102, and at least one through-hole LP is provided on the first electrode 101; a micron-pillar array KP is provided on the surface of the second electrode 102 on the side close to the first electrode 101, and at least one through-hole LP is provided on the second electrode 102 (in the figure, the through-hole LP on the second electrode 102 is covered due to the obstruction of the micron-pillar array KP); A micron-pillar array KP is provided on the surface of the three electrodes 103 near the second electrode 102, and a groove MP is provided on the third electrode 103. The material of each micron-pillar in the micron-pillar array KP on each electrode is a composite of SU-8 photoresist and silicon. A first support member 104 is provided between the first electrode 101 and the second electrode 102 to isolate the first electrode 101 and the second electrode 102. A second support member 105 is provided between the second electrode 102 and the third electrode 103 to isolate the second electrode 102 and the third electrode 103. Compared to a micron-pillar array made of silicon alone, the micron-pillar array KP made of the composite of SU-8 photoresist and silicon can further enhance the electric field effect and promote the occurrence of field emission, thereby improving the sensitivity and accuracy of the SF6 decomposition product sensor in detecting SF6 decomposition products. Furthermore, the SU-8 photoresist is flexible. Therefore, when the SF6 decomposition product sensor is subjected to vibration, the individual micropillars in the micropillar array KP are less likely to break, thereby preventing short circuits between the electrodes and extending the life of the SF6 decomposition product sensor. Furthermore, providing the micropillar array KP on the second electrode 102 increases the range of the reverse electric field, increasing the number of positive ions extracted and thereby increasing the extracted ion current. This, in turn, reduces the operating voltage of the SF6 decomposition product sensor and improves its sensitivity.

[0060] In one embodiment, referring to Figure 1 and Figure 2 As shown, the orthographic projection of the second electrode 102 on the third electrode covers the orthographic projection of the first electrode 101 on the third electrode 103 ; the orthographic projection of the second electrode 102 on the third electrode 103 covers at least a portion of the third electrode.

[0061] Optionally, in the first direction x, the length of the third electrode 103 is greater than the length of the second electrode 102, and the length of the second electrode 102 is greater than the length of the first electrode 101; in the second direction y, the length of the third electrode 103 is equal to the length of the second electrode 102, and the length of the second electrode 102 is equal to the length of the first electrode 101.

[0062] In one embodiment, referring to Figure 1 and Figure 2 As shown, the micron pillar array KP on the third electrode 103 is disposed around the groove MP to prevent electrons from overflowing.

[0063] In one embodiment, the SF6 decomposition product sensor further includes a battery; the first electrode 101 is connected to the negative electrode of the battery; the second electrode 102 is connected to the positive electrode of the battery, so that the SF6 decomposition product sensor can still be used normally without an external power supply.

[0064] Optionally, the SF6 decomposition product sensor further includes a charging interface for connecting to an external power source to charge the battery.

[0065] In one embodiment, the SF6 decomposition product sensor further includes a current detector; a first end of the current detector is connected to the third electrode 103, and a second end of the current detector is connected to the second electrode 102. In this way, the current detector detects the number of electrons from the second electrode 103 to the second electrode 102 to obtain a current value, and thus the concentration of the SF6 decomposition product can be obtained based on the current value.

[0066] In one embodiment, the SF6 decomposition product sensor further includes a housing, which is used to encapsulate the first electrode 101, the second electrode 102, and the third electrode 103. It should be noted that the housing is not completely enclosed and an opening is required to allow SF6 decomposition products to enter the area between the first electrode 101 and the second electrode 102 from the through hole LP on the first electrode 101.

[0067] In one embodiment, the SF6 decomposition product sensor also includes a pointer arranged on the shell, a concentration etching line arranged on the shell, and a driver and a single-chip microcomputer arranged in the inner cavity of the shell; the single-chip microcomputer is connected to the current detector; one end of the driver is connected to the single-chip microcomputer, and the other end of the driver is connected to the pointer.

[0068] In this embodiment, the SF6 decomposition product sensor operates as follows: a single-chip microcomputer receives a current signal from a current detector, which in turn sends a drive signal to a driver based on the current signal. The driver then rotates a pointer based on the drive signal. The user can obtain the concentration of SF6 decomposition products by reading the scale indicated by the pointer.

[0069] In one embodiment, the SF6 decomposition product sensor further includes a warning indicator light, which is connected to the single chip microcomputer.

[0070] Optionally, after the SF6 decomposition product sensor is activated, if the single-chip microcomputer does not receive a current signal from the current detector within a preset time period, a first warning signal is sent to the warning indicator light, causing the warning indicator light to display a first color. This can provide a warning effect in the event of a SF6 decomposition product sensor failure.

[0071] Optionally, when the current signal received by the current detector exceeds a threshold, the single chip microcomputer sends a second warning signal to the warning indicator light, causing the warning indicator light to display a second color. In this way, the effect of providing a warning when the concentration of SF6 decomposition products exceeds the standard can be achieved.

[0072] Any of the aforementioned SF6 decomposition product sensors can also detect electric field strength. This is done by actively operating the sensor in an electric field environment. The KP field enhancement of the micron-pillar array causes field ionization and field-induced electron emission of the SF6 decomposition products within the field, converting changes in DC, AC, and pulsed electric fields into changes in output current, enabling electric field strength detection. The electric field environment includes DC excitation conditions of 50V to 500V, and pulse excitation conditions with a peak voltage of 50V to 500V, a frequency range of 10kHz to 100kHz, and a duty cycle of 1% to 100%.

[0073] In one embodiment, Figure 3 As shown, a method for preparing an SF6 decomposition product sensor is also provided, and the preparation method includes:

[0074] Step 301: Acquire a first electrode and a second electrode provided with at least one through hole, and acquire a third electrode provided with a groove.

[0075] The first electrode, the second electrode and the third electrode are all made of silicon.

[0076] Step 302 : Using a deep reactive ion etching method based on an alternating reciprocating process, micron column arrays are formed on the first electrode, the second electrode, and the third electrode respectively.

[0077] Among them, for each electrode, in the process of preparing the micron column array, SU-8 photoresist is applied to the targeted electrode surface through a spin coating process to form an SU-8 single layer, and the SU-8 single layer is printed using two-photon molding technology. After printing, the uncured SU-8 photoresist is dissolved with ethanol solvent to obtain a micron column array on the targeted electrode surface.

[0078] Optionally, the flow ratio and etching rate of the C4F8 etching gas and SF6 shielding gas can be controlled by setting the device parameters of the external device to achieve etching of each electrode. The device parameters include pressure, RF power, source power, flow ratio of C4F8 etching gas and SF6 shielding gas, and other related parameters. Under the condition of continuously introducing C4F8 etching gas and SF6 shielding gas for 2s to 15s, the gas pressure output of the external device can be set to 6Pa, the RF power to 20W to 70W, and the source power to 220W to 450W, thereby achieving a flow ratio of C4F8 etching gas to SF6 shielding gas of 1.5:1 to 5:1 and an etching rate of 80A / min to 400A / min.

[0079] In step 303, a glass sheet is bonded between the first electrode and the second electrode to form a first support member, and a glass sheet is bonded between the second electrode and the third electrode to form a second support member. The thickness of the glass sheet is relatively small, that is, the glass sheet can be a thin glass sheet.

[0080] Each electrode requires a wire bonder, which can be used to bond the wires to the electrodes using a gold wire bonder. This connection is accomplished through a process of ball bonding and automated wire bonding. The first, second, and third electrodes also need to be packaged using ceramic packaging, which can be done using MEMS (Micro Electro Mechanical Systems) manufacturing technology.

[0081] In summary, the SF6 decomposition product sensor has the following advantages: (1) A micron column array KP is provided on the side of the first electrode 101 close to the second electrode 102, and a micron column array KP is provided on the surface of the second electrode 102 close to the first electrode 101, forming two opposing micron column arrays KP. This can enhance the effect of the measured electric field on the discharge characteristics of the first electrode 101 (cathode), and structurally constitutes a physical amplifier of the measured weak electric field, which is different from the passive and active amplifiers in the circuit. The silicon material has a small work function, and the micron column array KP structure has good tip emission characteristics and a large field enhancement factor, which has an amplifying effect on the measured weak electric field, so that the SF6 decomposition product sensor has the ability to detect weak electric fields and has high resolution. The micron column array KP structure is stable, has strong bombardment resistance, and has stable performance under the action of strong electric fields, which makes the sensor have a wide detection range.

[0082] (2) The through hole LP on the first electrode 101, the through hole on the second electrode 102, and the groove on the third electrode 103 are arranged according to the sizes of the through hole LP and the groove MP, so that the SF6 decomposition product sensor can obtain a one-to-one correspondence between the electric field to be measured and the collected current, and can detect the size of the DC electric field, AC electric field and pulse electric field, with the advantages of wide range, high resolution and high detection accuracy.

[0083] (3) By setting the photoresist for the etching operation in the production of micron pillars, the use of SU-8 photoresist overcomes the problem of insufficient aspect ratio of ordinary photoresist. It is very suitable for the preparation of high aspect ratio microstructures and has good mechanical properties, chemical corrosion resistance and thermal stability, meeting the tolerance requirements of micron pillar materials.

[0084] (4) The micron columns prepared by SU-8 photoresist can form a local electric field environment that is more conducive to electron emission and ionization of SF6 decomposition products, thereby effectively improving the detection sensitivity of the sensor to SF6 decomposition products.

[0085] The following is an implementation test of the above-mentioned SF6 decomposition product sensor.

[0086] Example 1: In the SF6 decomposition product sensor, the first electrode 101 has 9 through holes LP, and the aperture of the through holes LP on the first electrode 101 is 1.2 mm; the ratio of the distance between the first electrode 101 and the second electrode 102 to the aperture of the through holes LP on the first electrode 101 is 1 / 16; the central area of ​​the second electrode 102 has 9 through holes LP, and the aperture of the through holes LP on the second electrode 102 is 1.2 mm; the ratio of the distance between the second electrode 102 and the third electrode 103 to the aperture of the through holes LP on the second electrode 102 is 1 / 16; The structure of the micron pillar array KP on the first electrode 101, the second electrode 102, and the third electrode 103 is as follows: the distance between two adjacent micron pillars is 20 μm, the diameter of each micron pillar is 10 μm, and the height of each micron pillar is 60 μm; a groove MP is provided on the third electrode, the length of the groove MP in the first direction x and the second direction y are 6 mm and 8 mm respectively, and the length of the groove MP in the third direction z is 200 μm. The ratio of the spacing between the second electrode 102 and the third electrode 103 to the length of the groove MP in the third direction z is 15 / 40.

[0087] The micrometer column array KP in this embodiment is obtained by setting the pressure of the external equipment to 6 Pa, the RF power to 40 W, the source power to 220 W, the flow ratio of C4F8 etching gas to SF6 shielding gas to 1.5:1 and the etching rate to 100 A / min under the condition of continuously introducing SF6 shielding gas and C4F8 etching gas for 10 s.

[0088] The SF6 decomposition product sensor is in the following electric field environment: (1) DC excitation condition; (2) the voltage of the first electrode 101 is 0V; (3) the voltage of the second electrode 102 is 50V; (4) the voltage of the third electrode is 1V; (5) the temperature of the SF6 decomposition product is 25℃; (6) the pressure of the SF6 decomposition product is 100.1kPa; (7) the distance between two adjacent electrodes is 80μm~100μm.

[0089] The SF6 decomposition product sensor was used to test SO2, H2S, and CO respectively, and the results were as follows: Figure 4 The response characteristic curve of the SF6 decomposition sensor to SO2 under DC excitation is shown in the figure. Figure 5 The response characteristic curve of the SF6 decomposition product sensor to H2S under DC excitation is shown in the figure. Figure 6 The response characteristic curve of the SF6 decomposition product sensor to CO under DC excitation is shown.

[0090] Depend on Figure 4 It can be seen that when the concentration of SO2 gradually increases, the response current of the SF6 decomposition product sensor gradually decreases, which may be caused by the gas ionization reaction of SO2 between the electrodes of the SF6 decomposition product sensor.

[0091] Depend on Figure 5 It can be seen that when the concentration of H2S gradually increases, the response current of the SF6 decomposition product sensor shows a nonlinear downward trend, that is, it shows negative sensitivity.

[0092] Depend on Figure 6 It can be seen that the response current of the SF6 decomposition product sensor decreases overall with increasing CO concentration, exhibiting a nonlinear negative sensitivity characteristic. Within the high concentration range, the response current of the SF6 decomposition product sensor changes relatively smoothly, while exhibiting higher sensitivity in the low concentration range. This indicates that the SF6 decomposition product sensor has better sensitivity for low-concentration gas detection.

[0093] Example 2: In the SF6 decomposition product sensor, the first electrode 101 has 9 through holes LP, and the aperture of the through holes LP on the first electrode 101 is 0.6 mm; the ratio of the distance between the first electrode 101 and the second electrode 102 to the aperture of the through holes LP on the first electrode 101 is 1 / 600; the central area of ​​the second electrode 102 has 9 through holes LP, and the aperture of the through holes LP on the second electrode 102 is 0.5 mm; the ratio of the distance between the second electrode 102 and the third electrode 103 to the aperture of the through holes LP on the second electrode 102 is 1 / 500; the structure of the micron column array KP on the first electrode 101, the second electrode 102 and the third electrode 103: the distance between two adjacent micron columns is 10 μm, the diameter of each micron column is 5 μm, and the height of each micron column is 10 μm; a groove MP is provided on the third electrode, the length of the groove MP in the first direction x and the second direction y are both 1 mm, the length of the groove MP in the third direction z is 100 μm, and the ratio of the spacing between the second electrode 102 and the third electrode 103 to the length of the groove MP in the third direction z is 1.

[0094] The micrometer column array KP in this embodiment is obtained by setting the pressure of the external equipment to 6 Pa, the RF power to 40 W, the source power to 220 W, the flow ratio of C4F8 etching gas to SF6 shielding gas to 1.5:1 and the etching rate to 100 A / min under the condition of continuously introducing SF6 shielding gas and C4F8 etching gas for 10 s.

[0095] The SF6 decomposition product sensor is in the following electric field environment: (1) pulse excitation condition; (2) voltage peak is 80V; (3) frequency range is 80kHz; (4) pulse width is 50%.

[0096] The SF6 decomposition product sensor was used to test SO2, H2S, and CO respectively, and the results were as follows: Figure 7 The response characteristic curve of the SF6 decomposition product sensor to SO2 under pulse excitation is shown in the figure. Figure 8 The response characteristic curve of the SF6 decomposition sensor to H2S under pulse excitation is shown in the figure. Figure 9 The response characteristic curve of the SF6 decomposition product sensor to CO under pulse excitation is shown.

[0097] Depend on Figure 7 It can be seen that when pulse power supply is used, the response current value of the SF6 decomposition product sensor to different SO2 concentration points gradually decreases and shows a nonlinear single-value decrease relationship. This response trend is consistent with the response under DC excitation.

[0098] Depend on Figure 8 As can be seen, the response current of the SF6 decomposition sensor decreases with increasing H2S concentration, exhibiting a nonlinear, single-valued decrease. Its response trend remains consistent with that under DC excitation. Within the 0ppm-100ppm concentration range, the SF6 decomposition sensor's response current decreases significantly, while within the 100ppm-500ppm concentration range, the sensor's current decreases more gradually.

[0099] Depend on Figure 9 It can be seen that the response current of the SF6 decomposition product sensor decreases as the CO concentration increases. After multiple measurements, it was found that when the SF6 decomposition product sensor uses pulse power supply, the output response value of the SF6 decomposition product sensor is larger and the current variation range is wider. That is, compared with the DC working mode, the sensor output range and sensitivity under pulse excitation are improved.

[0100] Example 3: In the SF6 decomposition product sensor, the first electrode 101 has 9 through holes LP, and the aperture of the through holes LP on the first electrode 101 is 1.2 mm; the ratio of the distance between the first electrode 101 and the second electrode 102 to the aperture of the through holes LP on the first electrode 101 is 1 / 12; the central area of ​​the second electrode 102 has 9 through holes LP, and the aperture of the through holes LP on the second electrode 102 is 1.2 mm; the ratio of the distance between the second electrode 102 and the third electrode 103 to the aperture of the through holes LP on the second electrode 102 is 1 / 1 2. The structure of the micron pillar array KP on the first electrode 101, the second electrode 102, and the third electrode 103: the distance between two adjacent micron pillars is 15 μm, the diameter of each micron pillar is 8 μm, and the height of each micron pillar is 40 μm; a groove MP is provided on the third electrode, the length of the groove MP in the first direction x and the second direction y are both 0.5 mm, the length of the groove MP in the third direction z is 200 μm, and the ratio of the spacing between the second electrode 102 and the third electrode 103 to the length of the groove MP in the third direction z is 1 / 2.

[0101] The micrometer column array KP in this embodiment is obtained by setting the pressure of the external equipment to 6 Pa, the RF power to 40 W, the source power to 220 W, the flow ratio of C4F8 etching gas to SF6 shielding gas to 1.5:1 and the etching rate to 100 A / min under the condition of continuously introducing SF6 shielding gas and C4F8 etching gas for 10 s.

[0102] The SF6 decomposition product sensor is in the following electric field environment: (1) pulse excitation condition; (2) voltage peak is 80V; (3) frequency range is 80kHz; (4) pulse width is 50%.

[0103] The SF6 decomposition product sensor was used to test SO2, H2S, and CO respectively, and the results were as follows: Figure 10 The response characteristic curve of the SF6 decomposition product sensor to SO2 under pulse excitation is shown in the figure. Figure 11 The response characteristic curve of the SF6 decomposition sensor to H2S under pulse excitation is shown in the figure. Figure 12 The response characteristic curve of the SF6 decomposition product sensor to CO under pulse excitation is shown.

[0104] Figure 10 、 Figure 11 and Figure 12 Respectively Figure 7 、 Figure 8 and Figure 9 The characteristics of the display are not described here. It should be noted that Figure 4-12 The middle collector refers to the third electrode 103 .

[0105] Table 1 shows a comparison between the SF6 decomposition product sensor of the present application and the sensor in the prior art.

[0106] Table 1

[0107]

[0108] The calculation formula for the sensitivity of the above SF6 decomposition product sensor is: ,in, is the sequence number of different SF6 decomposition product concentration points, ; is the average value of the response current of the third electrode of the SF6 decomposition product sensor; is the concentration of SF6 decomposition products.

[0109] Normalized sensitivity =SF6 decomposition product sensor sensitivity SF6 decomposition product sensor output range;

[0110] SF6 decomposition product sensor output range = maximum response current - minimum response current.

[0111] Compared to the performance indicators of existing related sensors, the above-mentioned SF6 decomposition product sensor has superior detection range, exceeding that of existing related sensors by approximately one order of magnitude. Furthermore, the SF6 decomposition product sensor in this application is manufactured using MEMS technology and has a volume of only 7mm × 11mm × 2mm. This SF6 decomposition product sensor has further advantages in miniaturization and has excellent application prospects.

[0112] It should be understood that, although the various steps in the flowcharts involved in the various embodiments described above are displayed in sequence according to the instructions of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments described above can include multiple steps or multiple stages, and these steps or stages are not necessarily executed and completed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0113] It should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0114] It will be understood that the terms "first," "second," etc., used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor without departing from the scope of this application. The first resistor and the second resistor are both resistors, but they are not the same resistor.

[0115] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if there is transmission of electrical signals or data between the connected circuits, modules, units, etc.

[0116] It is understood that “at least one” refers to one or more, “a plurality” refers to two or more, and “at least a portion of an element” refers to a portion or all of an element.

[0117] As used herein, the singular forms "a," "an," and "the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include," "comprising," "having," and the like specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Furthermore, the term "and / or" as used in this specification includes any and all combinations of the relevant listed items.

[0118] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0119] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A SF6 decomposition product sensor, characterized in that: The SF6 decomposition product sensor includes a first electrode, a second electrode and a third electrode stacked in sequence; A micron-pillar array is provided on the surface of the first electrode on the side close to the second electrode, and at least one through-hole is provided on the first electrode; a micron-pillar array is provided on the surface of the second electrode on the side close to the first electrode, and at least one through-hole is provided on the second electrode; a micron-pillar array is provided on the surface of the third electrode on the side close to the second electrode, and a groove is provided on the third electrode; wherein the material of each micron pillar in the micron-pillar array on each electrode is a composite of SU-8 photoresist and silicon material; A first support member is provided between the first electrode and the second electrode to isolate the first electrode from the second electrode; and a second support member is provided between the second electrode and the third electrode to isolate the second electrode from the third electrode.

2. The SF6 decomposition product sensor according to claim 1, characterized in that: The orthographic projection of the second electrode on the third electrode covers the orthographic projection of the first electrode on the third electrode; The orthographic projection of the second electrode on the third electrode covers at least a portion of the third electrode.

3. The SF6 decomposition product sensor according to claim 1, characterized in that The micron column array on the third electrode is arranged around the groove.

4. The SF6 decomposition product sensor according to claim 1, characterized in that The SF6 decomposition product sensor also includes a battery; The first electrode is connected to the negative electrode of the battery; the second electrode is connected to the positive electrode of the battery.

5. The SF6 decomposition product sensor according to claim 1, characterized in that: The SF6 decomposition product sensor also includes a current detector; A first terminal of the current detector is connected to the third electrode, and a second terminal of the current detector is connected to the second electrode.

6. The SF6 decomposition product sensor according to claim 5, characterized in that: The SF6 decomposition product sensor further includes a housing, which is used to encapsulate the first electrode, the second electrode, and the third electrode.

7. The SF6 decomposition product sensor according to claim 6, characterized in that: The SF6 decomposition product sensor further includes a pointer provided on the housing, a concentration etching line provided on the housing, and a driver and a single chip microcomputer provided in the inner cavity of the housing; The single chip microcomputer is connected to the current detector; One end of the driver is connected to the single chip microcomputer, and the other end of the driver is connected to the pointer.

8. The SF6 decomposition product sensor according to claim 7, characterized in that: The SF6 decomposition product sensor further includes an early warning indicator light, which is connected to the single chip microcomputer.

9. The SF6 decomposition product sensor according to claim 4, characterized in that: The SF6 decomposition product sensor further includes a charging interface for connecting to an external power source to charge the battery.

10. A method for preparing an SF6 decomposition product sensor, characterized in that: The method is used to prepare the SF6 decomposition product sensor according to any one of claims 1 to 9, and the method comprises: Obtaining a first electrode and a second electrode provided with at least one through hole, and obtaining a third electrode provided with a groove; wherein the materials of the first electrode, the second electrode, and the third electrode are all silicon materials; A deep reactive ion etching method based on an alternating reciprocating process is used to prepare micron pillar arrays on the first electrode, the second electrode, and the third electrode, respectively. For each electrode, during the preparation of the micron pillar array, SU-8 photoresist is applied to the surface of the electrode to form an SU-8 monolayer by a spin coating process, and the SU-8 monolayer is printed using a two-photon molding technique. After printing, uncured SU-8 photoresist is dissolved using an ethanol solvent to obtain a micron pillar array on the surface of the electrode. A glass sheet is bonded between the first electrode and the second electrode to form a first support member, and a glass sheet is bonded between the second electrode and the third electrode to form a second support member.

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