A sensor for detecting dissolved C2H2 gas in power transformer oil

Abstract

A sensor for detecting C2H2 gas dissolved in power transformer oil belongs to the technical field of semiconductor gas sensors. The problem that the existing semiconductor C2H2 gas sensor cannot respond to C2H2 gas under oxygen-free conditions is solved. The base is a cube, a square through hole is formed in the center of the cube, and a supporting film, a heater, an isolation film, an interdigital electrode and a gas sensitive material layer are attached on one surface of the cube with the through hole; the centers of the gas sensitive material layer, the interdigital electrode, the isolation film, the heater and the supporting film correspond to the through hole of the cube; the isolation film is used for isolating the electrical connection between the interdigital electrode and the heater, the gas sensitive material layer is attached to the center of the upper surface of the interdigital electrode, and the resistance of the gas sensitive material layer changes with the concentration of the detected gas; the gas sensitive material layer is made of SnO2 doped with In and Pt elements. The present application is suitable for detecting C2H2 gas dissolved in power transformer oil.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of semiconductor gas sensors. BACKGROUND

[0002] With the rapid development of China's electric power industry, the scale of the power system continues to expand, and power transformers are indispensable core equipment in the power system, and transformer faults will affect the normal operation of the entire power system. The detection of dissolved gas components in transformer oil can realize timely warning of transformer faults and avoid affecting the operation of the power system. C2H2 gas as a typical dissolved characteristic gas in transformer oil, its release in the transformer often means that the transformer has an overheating fault, and timely and effective detection of C2H2 gas is of great significance to maintain the safe operation of the transformer equipment. At present, most of the traditional gas sensitive performance tests take dry air as the background gas, however, in the real transformer detection application scene, a series of pretreatments are needed before gas detection, including sampling, purification of transformer oil, degassing separation of dissolved gas in oil, etc. The vacuum degassing process of dissolved gas in transformer oil needs to be carried out, and after vacuum degassing, chromatographic column separation is needed, in order to prevent the separation column from being oxidized at high temperature, nitrogen (N2) is often used as the carrier gas. The existing semiconductor C2H2 sensor needs oxygen to be activated on the surface to form active oxygen, and then reacts with C2H2 to generate corresponding electrical signals, which cannot respond to C2H2 gas under anaerobic conditions. SUMMARY

[0003] The application is to solve the problem that the existing semiconductor C2H2 gas sensor cannot respond to C2H2 gas under anaerobic conditions, and provides a sensor for detecting dissolved C2H2 gas in power transformer oil.

[0004] The sensor for detecting dissolved C2H2 gas in power transformer oil, comprising: a gas sensitive material layer, an interdigital electrode, an isolation film, a heater, a supporting film and a base;

[0005] The base is a cube, a square through hole is formed in the center of the cube, and a supporting film, a heater, an isolation film, an interdigital electrode and a gas sensitive material layer are sequentially attached to one surface of the cube with the through hole;

[0006] The centers of the gas sensitive material layer, the interdigital electrode, the isolation film, the heater and the supporting film correspond to the through hole of the cube;

[0007] The isolation film is used to isolate the electrical connection between the interdigital electrode and the heater,

[0008] The gas sensitive material layer is attached to the center of the upper surface of the interdigital electrode, and the resistance of the gas sensitive material layer changes with the concentration of the detected gas; the gas sensitive material layer is made of SnO2 doped with In and Pt elements;

[0009] The heating temperature of the heater is adjusted by adjusting the input voltage of the heater.

[0010] The interdigital electrode and the heater are respectively connected to the measurement circuit through lead wires.

[0011] Further, in the present application, the gas sensitive material layer is made of SnO2 doped with In and Pt elements sintered at 600°C.

[0012] Further, in the present application, the specific manufacturing process of the gas sensitive material is as follows:

[0013] Step one, 0.8 g of SnCl2·2H2O is added to 10 mL of ethanol solution, and then mixed with 10 mL of N,N-dimethylformamide solution, 4 g of polyvinylpyrrolidone, 1% mol of H2PtCl6·6H2O and 0.8% mol of InCl3·4H2O to perform electrospinning, to obtain a polymer mixture;

[0014] Step two, the polymer mixture is sintered at 600°C for 5 hours to make In and Pt doped into the SnO2 lattice, to obtain 0.8% In-1% Pt-SnO2 powder;

[0015] Step three, the 0.8% In-1% Pt-SnO2 powder is uniformly dispersed in 5 mL of ethanol to obtain the gas sensitive material.

[0016] Further, in the present application, the power supply voltage of electrospinning is 20 kV, and the pushing speed is 0.6 mL / h.

[0017] Further, in the present application, the gas sensitive material is uniformly coated on the interdigital electrode by using the micro-droplet injection method.

[0018] Further, in the present application, the base is made of a silicon substrate.

[0019] Further, in the present application, the heater is made of gold, platinum or nickel material.

[0020] Compared with the existing C2H2 sensor, the C2H2 gas sensor based on In / Pt-doped SnO2 in the application introduces more active sites and defects in the SnO2 nanofiber by metal element In / Pt doping, which significantly improves the sensitivity. At the same time, the electrospinning method reduces the grain size of the SnO2 nanofiber, improves its specific surface area, and is beneficial to the interaction with C2H2 gas molecules. The sensor has high response, fast response speed and excellent stability. The excellent performance shows that the sensor has broad prospects for rapid and accurate detection of C2H2 in an oxygen-free environment. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a structure exploded view of the sensor of the application.

[0022] Figure 2 It is a specific manufacturing process schematic diagram of the gas sensitive material.

[0023] Figure 3 It is a transmission electron microscope picture of 0.8% In-1%Pt-SnO2 nanofiber in the embodiment.

[0024] Figure 4 It is a response-recovery curve of the sample to 5-50 ppm C2H2 in the embodiment.

[0025] Figure 5 It is a relationship between the response value of the 0.8% In-1%Pt-SnO2 sensor to C2H2 and the gas concentration in the embodiment.

[0026] Figure 6 It is a response-recovery curve of the 0.8% In-1%Pt-SnO2 sensor to 5 ppm C2H2 under continuous dynamic cycle in the embodiment.

[0027] Figure 7 It is a response-recovery curve of the 0.8% In-1%Pt-SnO2 sensor to 5 ppm C2H2 in the embodiment. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application. It should be noted that the embodiments in the application and the features in the embodiments can be combined with each other without conflict.

[0029] DETAILED DESCRIPTION Figure 1To illustrate the embodiment, the embodiment provides a sensor for detecting C2H2 gas dissolved in power transformer oil, which comprises a gas sensitive material layer 1, an interdigital electrode 2, an isolation film 3, a heater 4, a supporting film 5 and a base 6.

[0030] The base is a cube, a square through hole is formed in the center of the cube, and the surface of the cube with the through hole is sequentially attached with the supporting film 5, the heater 4, the isolation film 3, the interdigital electrode 2 and the gas sensitive material layer 1.

[0031] The center of the gas sensitive material layer 1, the interdigital electrode 2, the isolation film 3, the heater 4 and the supporting film 5 corresponds to the through hole of the cube.

[0032] The isolation film 3 is used for isolating the electrical connection between the interdigital electrode 2 and the heater 4,

[0033] The gas sensitive material layer 1 is attached to the center of the upper surface of the interdigital electrode 2, and the resistance of the gas sensitive material layer 1 changes with the concentration of the detected gas; the gas sensitive material layer 1 is made of In and Pt doped SnO2.

[0034] The heating temperature of the heater 4 is adjusted by adjusting the input voltage of the heater 4.

[0035] The interdigital electrode 2 and the heater 4 are respectively connected to the measurement circuit through the lead wire.

[0036] Further, in the present application, the gas sensitive material layer is made of In and Pt doped into the SnO2 lattice by sintering at 600°C.

[0037] Further, in the embodiment, the specific manufacturing process of the gas sensitive material is as follows:

[0038] Step one, 0.8 g of SnCl2·2H2O is added to 10 mL of ethanol solution, and then mixed with 10 mL of N,N-dimethylformamide (DMF) solution, 4 g of polyvinylpyrrolidone (PVP), 1% mol of H2PtCl6·6H2O and 0.8% mol of InCl3·4H2O to perform electrospinning, and a polymer mixture is obtained;

[0039] Step two, the polymer mixture is sintered at 600°C for 5 hours to make In and Pt doped into the SnO2 lattice, and 0.8% In-1% Pt-SnO2 powder is obtained;

[0040] Step three, the 0.8% In-1% Pt-SnO2 powder is uniformly dispersed in 5 mL of ethanol to obtain the gas sensitive material.

[0041] Further, in the embodiment, the power supply voltage for electrospinning is 20 kV, and the propelling speed is 0.6 mL / h.

[0042] Further, in the embodiment, the gas-sensitive material is uniformly coated on the interdigital electrode by using the micro-droplet injection method.

[0043] Further, in the embodiment, the base 6 is made of a silicon substrate.

[0044] Further, in the embodiment, the heater 4 is made of gold, platinum or nickel. Specific embodiment: mixing of raw materials. 0.8 g of commercial SnCl2·2H2O is added to 10 mL of ethanol, 10 mL of N,N-dimethylformamide (DMF), 4 g of polyvinylpyrrolidone (PVP) and 0.8% mol of InCl3·4H2O, and electrospinning is performed at a power supply voltage of 20 kV and a propelling speed of 0.6 mL / h.

[0045] Synthesis of 0.8% In-SnO2. The mixture obtained by electrospinning is sintered at 600°C for 5 hours to enable In doping into the SnO2 lattice.

[0046] Preparation of electrode sheets. The 0.8% In-SnO2 powder is uniformly dispersed in an ethanol solution, and is uniformly coated on the electrode sheets by using the micro-droplet injection method, and is dried at room temperature.

[0047] Device welding. The electrode sheets obtained are welded to the hexagonal base by using a spot welding device, and a sensor device based on 0.8% In-SnO2 is obtained.

[0048] The device prepared is subjected to C2H2 gas-sensitive performance testing, and the response value thereof to 5 ppm C2H2 at 200°C is 0.7.

[0049] Figure 2 Flowchart of the experimental process of the embodiment. Figure 3 The transmission electron microscope picture of the 0.8% In-1% Pt-SnO2 nanofiber in the embodiment is shown, and it can be seen from the picture that the crystal grain size of the 0.8% In-1% Pt-SnO2 is small, the crystal grain is loosely accumulated, the surface has fine pores, and the hollow structure has a developed internal space. Figure 4 The response-recovery curves of the 0.8% In-1% Pt-SnO2 sensor in the embodiment to 5, 10, 20, 30, 40 and 50 ppm C2H2 gas are shown, and it can be calculated that the response values thereof to 5, 10, 20, 30, 40 and 50 ppm C2H2 gas at 200°C are 0.7, 7.2, 8.9, 10.0, 10.6 and 11.1 respectively. Figure 5The response value of the 0.8% In-1% Pt-SnO2 sensor in the example and the relationship with the C2H2 gas concentration (5-50 ppm) are obtained by fitting the curve, and as the C2H2 gas concentration increases, the response value of the 0.8% In-1% Pt-SnO2 sensor to C2H2 increases, and the growth rate of the response value of the 0.8% In-1% Pt-SnO2 sensor to C2H2 gas decreases, and the fitting curve finally tends to be flat. Figure 6 The response and recovery time of the 0.8% In-1% Pt-SnO2 sensor to 5 ppm C2H2 in the example is shown, and the response time of the 0.8% In-1% Pt-SnO2 sensor to 5 ppm C2H2 gas is calculated to be 190 s, and the recovery time is 427 s. Figure 7 The response-recovery curve of the 0.8% In-1% Pt-SnO2 sensor in the example under continuous dynamic cycle to 5 ppm C2H2 can be seen that the response value of the 0.8% In-1% Pt-SnO2 sensor to 5 ppm C2H2 does not appear obvious attenuation in the continuous five cycles, the baseline is relatively stable, and the response recovery time also has little change, which shows strong stability and repeatability.

[0050] Since the traditional MOS sensor is based on the oxygen depletion layer mechanism, oxygen needs to be adsorbed on the surface of the gas sensitive material to consume part of the electrons on the material surface, and then the oxygen ions adsorbed on the surface react with the gas to release electrons back to the MOS material, thereby forming an electrical signal response, but in the detection environment of transformer oil, the gas needs to be separated by a chromatographic column in advance during detection, and the carrier gas required for the chromatographic column to separate the gas is nitrogen, so there is no oxygen in the whole system. Therefore, the existing sensor cannot be realized under the condition of no oxygen, and the sensor described in the application can quickly respond to acetylene gas under the condition of no oxygen, and the detection accuracy is obviously improved.

[0051] Compared with the prior art, the positive effects of the application are: realizing excellent gas sensitive performance of C2H2 in an oxygen-free environment; the preparation method is simple, the material source is simple, the price is low, the sensor performance is stable, and the response is rapid.

[0052] Although the application is described herein with reference to specific embodiments, it should be understood that these examples are merely illustrative of the principles and applications of the application. It should therefore be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed, without departing from the spirit and scope of the application as defined in the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways other than those described by the original claims. It should also be understood that features described in connection with individual embodiments can be used in other described embodiments.

Claims

1. A sensor for detection of C2H2 gas dissolved in power transformer oil, characterized in that, It comprises a gas sensitive material layer (1), an interdigital electrode (2), an isolation film (3), a heater (4), a supporting film (5) and a base (6). The base is a cube, a square through hole is formed in the center of the cube, and the supporting film (5), the heater (4), the isolation film (3), the interdigital electrode (2) and the gas sensitive material layer (1) are sequentially attached to one surface of the cube with the through hole. The centers of the gas sensitive material layer (1), the interdigital electrode (2), the isolation film (3), the heater (4) and the supporting film (5) correspond to the through hole of the cube. The isolation film (3) is used for isolating the electrical connection between the interdigital electrode (2) and the heater (4). The gas sensitive material layer (1) is attached to the center of the upper surface of the interdigital electrode (2), and the resistance of the gas sensitive material layer (1) changes with the concentration of the detected gas. The gas sensitive material layer (1) is made of SnO2 doped with In and Pt elements. The heating temperature of the heater (4) is adjusted by adjusting the input voltage of the heater (4). The interdigital electrode (2) and the heater (4) are respectively connected to the measurement circuit through lead wires.

2. The sensor for detecting C2H2 gas dissolved in the oil of a power transformer according to claim 1, characterized by, The gas sensitive material layer is made of SnO2 doped with In and Pt elements sintered at 600°C.

3. A sensor for detection of C2H2 gas dissolved in electrical transformer oil according to claim 1, characterized in that, The specific manufacturing process of the gas sensitive material is as follows: Step one, 0.8 g of SnCl2·2H2O is added to 10 mL of ethanol solution, and then mixed with 10 mL of N,N-dimethylformamide (DMF) solution, 4 g of polyvinylpyrrolidone (PVP), 1% mol of H2PtCl6·6H2O and 0.8% mol of InCl3·4H2O to perform electrospinning, and a polymer mixture is obtained; Step two, the polymer mixture is sintered at 600°C for 5 hours to make In and Pt doped into the SnO2 crystal lattice, and 0.8% In-1% Pt-SnO2 powder is obtained; Step three, the 0.8% In-1% Pt-SnO2 powder is uniformly dispersed in 5 mL of ethanol to obtain the gas sensitive material.

4. The sensor for detecting C2H2 gas dissolved in the oil of a power transformer according to claim 1 or 2, characterized by, The power voltage of electrospinning is 20 kV, and the pushing speed is 0.6 mL / h.

5. The sensor for detecting C2H2 gas dissolved in the oil of a power transformer according to claim 1 or 2, characterized by, The gas sensitive material is uniformly coated on the interdigital electrode by using the microdroplet injection method.

6. The sensor for detecting C2H2 gas dissolved in the oil of a power transformer according to claim 1, characterized by, The base (6) is made of a silicon substrate.

7. A sensor for detecting C2H2 gas dissolved in power transformer oil according to claim 1, characterized in that, The heater (4) is made of gold, platinum or nickel material.

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