KR101303931B1 - Complexed structure having separation membrane used for sensing gas, gas-sensing apparatus comprising the same, method and apparatus for measuring gas concentration - Google Patents

Abstract

Provided are a composite membrane structure for a gas sensor for monitoring transformer insulation oil degradation in real time, a gas sensor device including the same, and a method and apparatus for measuring gas concentration using the same. By measuring quantitatively and in real time the concentrations of various types of gas in the oil, it is possible to locally diagnose the abnormality of the transformer and the part of the transformer. It is possible to prevent and also to predict the residual life of the insulating oil in the transformer.

Description

Complex membrane structure for gas sensor, gas sensor device including the same, method and device for measuring gas concentration using same {Complexed structure having separation membrane used for sensing gas, gas-sensing apparatus comprising the same, method and apparatus for measuring gas concentration}

The present specification relates to a composite membrane structure for a gas sensor, a gas sensor device including the same, a method and a device for measuring a gas concentration using the same, and in detail, may monitor real-time deterioration of insulating oil of a power equipment such as a transformer using insulating oil. The present invention relates to a composite membrane structure for a gas sensor, a gas sensor device including the same, and a gas concentration measuring method and apparatus using the same.

Transformers are very important for power supply. In order to prevent sudden failure of a power device and prevent power failures as well as predict the life of the power device, and to operate the power device economically, the condition of the transformer can be identified so that the abnormal state of the transformer can be identified and the accident can be prevented in advance. There is a need for condition monitoring technology that can be monitored.

Condition diagnosis techniques used for diagnosing internal abnormalities that may occur in transformer insulating oils include gas analysis in oil, power factor and moisture measurement method, partial discharge measurement method, low pressure surge test. Law is used.

Among them, the oil-in-oil analysis method that can measure the degradation of the insulating oil generated in the transformer as the degradation thereof is technically reliable and has the advantage of being easy to apply in real time is most widely used.

More detailed description of the oil in gas analysis method is as follows.

The transformer always receives constant thermal energy, depending on the use of an internally located electrical coil, and a high temperature partial arc discharge may occur in the event of local dielectric breakdown inside the transformer.

Along with these phenomena, hydrocarbon-based insulating oil is thermally decomposed to generate gases such as hydrogen (H ₂ ), methane (CH ₄ ), acetylene (C ₂ H ₂ ), and ethylene (C ₂ H ₄ ). do. In particular, when there is an insulating material such as an insulating paper, a press board, or bakelite at the heating portion, gas such as carbon monoxide (CO) or carbon dioxide (CO ₂ ) is also generated.

For reference, among these gaseous gases, especially gases such as hydrogen, methane, acetylene, ethylene, ethane, propane, etc. are highly combustible and thus very important components in diagnosis for transformer safety management.

Since these gases are mostly dissolved in insulating oil, it is possible to diagnose whether there are any abnormalities in the transformer and in which part of the transformer locally by extracting these gases quantitatively and qualitatively.

In order to analyze the gas in the insulating oil, a sample of the insulating oil is taken from the transformer in operation and transported to the experimental analysis chamber to extract the gas, the gas analysis (Gas Chromatography) to analyze the gas is most commonly used.

However, these laboratory analytical methods are not reliable due to all the human error factors that may occur in the process of taking a standard sample, and as a result, analysis takes a long time.

Recently, attempts have been made to continuously measure and monitor by installing a real-time measuring device directly inside and outside the transformer.

For example, in order to sample the gas in oil dissolved in the insulating oil from inside the transformer, a micro filter and an ultra filtration filter element capable of filtering the gas in oil from the insulating oil medium may be used.

However, as a result of the researches of the present inventors, in this case, since the oil in the oil dissolved in the insulating oil is extracted through the filter element having a high pressure difference before and after the filter, a negative pressure is applied to the rear end of the filter using a vacuum pump to sample the gas. Can be done.

However, in view of the relatively short life of the vacuum pump, it is the opinion of the present inventors that the above method is not very practical as a real-time state diagnosis technology of a transformer that has a long life of 10 to 30 years or more.

As another specific method for analyzing the gas in the oil dissolved in the insulating oil, Patent Literature 1 extracts and separates the dissolved gas in the insulating oil using an oil / gas separation membrane, and uses an electrochemical gas sensor. A transformer fault monitoring apparatus and method for detecting a fault inside a transformer by detecting a total concentration of gas reacting to a sensor is disclosed.

However, according to the results of the present inventors, Patent Document 1 does not specifically describe the method and effect of forming the separator.

On the other hand, semiconductor type gas sensors made of metal oxides such as tin oxide, tungsten oxide and zirconium oxide are generally known to be able to quantitatively measure the concentration of gas components because the electrical properties of the sensor material change in response to the gas atmosphere. have. For reference, such a semiconductor gas sensor is widely used to measure contaminated gases in an atmospheric environment.

However, when the semiconductor gas sensor element is in direct contact with the insulating oil medium for measuring transformer oil deterioration or directly or indirectly with the oil vapor generated from the insulating oil, the contaminants contaminate the surface of the semiconductor gas sensor element. It is very likely that you will get incorrect measurement results.

In Patent Document 2, Patent Document 3, and Patent Document 4, a gas analysis device and analysis method for insulating oil that performs concentration detection of gas in oil using a commercially available semiconductor gas sensor, and a separator for extracting and separating dissolved gas in insulating oil are selectively used. It is disclosed that it can.

However, according to the results of the present inventors, the above patent documents also do not specifically describe the method and effect of forming the separator.

In addition, according to the results of the present inventors, in the case of Patent Document 2, in order to obtain a plurality of individual concentrations of gases, the hydrogen concentration is first calculated, and then carbon monoxide concentration is sequentially calculated, such as a method of calculating hydrogen concentration. As such, it is assumed that a special sensor capable of sensing only a specific gas is not suitable for the actual use of a general-purpose semiconductor gas sensor.

Meanwhile, Patent Document 5 proposes to use a porous PTFE polymer material having a thickness of 1 μm to 1,000 μm and a porosity of about 5% to 99% as a use for separating dissolved gas in a fluid. Specific examples are provided for stretching, solvent extraction, or casting the surface of the polymeric material to obtain a surface.

In addition, Patent Document 6 discloses a porous polymer material (poly (tetrafluoroethylene) having a thickness of about 1 mm to 5 mm and a pore size of about 0.001 mm to 0.1 mm for the purpose of extracting and separating dissolved gas components in an oil medium. And poly (tetrafluoroethylene-cohexafluoropropylene), and in order to obtain porosity of the oil / gas separator material, argon gas of 13.56 MHz radio frequency (RF) form having an output of about 100 W to 500 W and a pressure of 0.5 Pa to 50 Pa A method of processing a hole in the surface of a material by bombarding the polymer material with a nitrogen gas laser for 10 to 30 minutes is shown as a specific example.

However, according to the results of the present inventors, even in the methods of the above patent documents, there is sufficient possibility that pressure difference occurs before and after the separation membrane, and in particular, the separation membrane has a complicated processing process and requires a special processing method for material processing. There is this.

Republic of Korea Patent No. 10-0342421 Republic of Korea Patent Publication No. 10-2007-0112014 Japanese Patent Laid-Open No. 5-52787 Japanese Patent Laid-Open No. 6-160329 U.S. Patent 6,800,118 U.S. Patent 7,811,362

In the embodiments of the present invention, a composite membrane structure including a separator of insulating oil and dissolved gas used in conjunction with a semiconductor gas sensor, wherein the insulating oil does not pass, but gas in oil can pass, and the pressure difference between front and rear is small, and The present invention provides a composite membrane structure for a gas sensor and a gas sensor device including the same, the strength of which is not deteriorated and which can prevent contamination due to the insulating oil medium and moisture in the insulating oil.

In addition, in the embodiments of the present invention, without having to select a specific semiconductor gas sensor that reacts only to a specific gas, a gas that can be used to measure the concentration of each type of gas with high reliability and easily using a general-purpose semiconductor gas sensor It is intended to provide a method and apparatus for measuring concentration.

In order to solve the above problems, embodiments of the present invention, the support having a mesh; A coating layer of a porous material placed on the support and obtained by a sol-gel method; And a self-assembled monomolecular film positioned on the coating layer of the porous material.

In an exemplary embodiment of the invention, the self-assembled monomolecular membrane is oleophobic and hydrophobic simultaneously.

In an exemplary embodiment of the invention, the self-assembled monomolecular membrane consists of a fluorinated hydrocarbon-based silane.

In an exemplary embodiment of the invention, the support with the mesh is a metal or ceramic support.

In an exemplary embodiment of the invention, the porous material obtained by the sol-gel method is an organometallic compound or a ceramic.

In an exemplary embodiment of the present invention, the porous material obtained by the sol-gel method, as a precursor, methyl trimethoxy silane (methyl trimethoxi silane), tetramethoxy silane (tetramethoxi silane), dimethyldimethoxi (dimethyldimethoxi silane, tetraethoxysilane (tetraethoxi silane), methyl triethoxi silane (methyl triethoxi silane), dimethyldiethoxi silane, phenyl trimethoxyoxi silane, diphenyldimethoxysilane silane, phenyl triethoxi silane, diphenyldiethoxi silane, decyltrimethoxi silane, and isobutyltrimethoxi Alkoxy compounds represented by the above alkoxysilanes or M (OR) x [wherein M is a metal or metalloid, R is an alkyl group having 1 to 10 carbon atoms] Or a polymer material obtained by the sol-gel method using a mixture.

Embodiments of the invention also include a semiconductor gas sensor; And the composite membrane structure spaced apart from the semiconductor gas sensor.

In exemplary embodiments of the present invention, the gas sensor device may include: a housing in which the semiconductor gas sensor and the composite membrane structure are accommodated or mounted; A lower plate supporting the semiconductor gas sensor; And an upper plate covering the composite separator structure therefrom, wherein the lower plate and the upper plate are fastened to the housing, respectively.

In exemplary embodiments of the present invention, the gas sensor device includes a semiconductor gas sensor array in which one or more of the composite membrane structure and the semiconductor gas sensor are arranged.

In exemplary embodiments of the present invention, the gas sensor device comprises: a first housing for receiving or mounting the semiconductor gas sensor array; A second housing accommodating or mounting the composite membrane structure; An end cap fastened to the lower portion of the first housing; And an adapter fastened to an upper portion of the second housing, wherein the first housing and the second housing are fastened to each other.

In exemplary embodiments of the present invention, the gas sensor device may further include a gas seal pad positioned on one side or both sides of the composite membrane structure.

In exemplary embodiments of the present invention, the gas sensor device may further include a seal member in the housing.

In exemplary embodiments of the present invention, the gas sensor device may further include a connection member connecting the first housing and the end cap.

In exemplary embodiments of the present invention, the gas sensor device performs sensing by contacting the insulating oil of the transformer or the vapor of the insulating oil.

In embodiments of the present invention, there is also provided a method of sensing a dissolved gas of insulating oil with at least one semiconductor gas sensor to obtain a sensor resistance value Rs; And obtaining an individual gas concentration in the dissolved gas of the insulating oil from the obtained resistance value (Rs) by the following Equation (1).

[Equation 1]

[G] _i = [k _ij ] ^-1 [[Log (Rs / Ro)] _i- [∑a _ij ] _i ] (i, j = 1 ~ n)

(In Equation 1, Ro is a sensor resistance value which is a constant measured when the concentration of the individual gas is fixed under clean air conditions, Rs / Ro is a sensor resistance ratio, and i is an individual semiconductor gas sensor used for gas concentration measurement. The number assigned to, j is the number assigned to the individual gas to be measured, n is the total number of gases to be measured, G is the concentration of the individual gas to be measured, [G] _i is the individual gas to be measured The matrix consisting of the concentrations, k _ij is the rate of change of the sensor resistance ratio according to the change of the gas concentration having the j number in the semiconductor gas sensor having the i number, which is determined according to the gas of the j number in the semiconductor gas sensor having the i number, or The constant corrected from this, [k _ij ] ^-1 is the inverse matrix of the matrix consisting of k _ij when i and j change from 1 to n, respectively, [Log (Rs / Ro)] _i is i Changes from 1 to n For a matrix consisting of the logarithm of the sensor resistance ratio, a _ij is a minimum sensor resistance ratio value to measure the gas concentration with j number in the semiconductor gas sensor having an i number, in a semiconductor gas sensor having an i number determined by the number j of the gas or the corrected constant value therefrom, Σa _ij is the sum of the a _ij if the change in the fixed and in each i and j is 1, the number of n, [Σa _{ij] i} is the i Matrix consisting of ∑a _ij when changing from 1 to n.)

In exemplary embodiments of the present invention, the gas concentration measuring method may use a semiconductor gas sensor in a gas sensor device including a semiconductor gas sensor and the composite membrane structure spaced apart from the semiconductor gas sensor.

Embodiments of the invention also include one or more semiconductor gas sensors; And a computing device for obtaining an individual gas concentration in the dissolved gas of the insulating oil from the sensor resistance value Rs obtained by sensing the dissolved gas of the insulating oil from the semiconductor gas sensor according to Equation 1 below. To provide.

[Equation 1]

[G] _i = [k _ij ] ^-1 [[Log (Rs / Ro)] _i- [∑a _ij ] _i ] (i, j = 1 ~ n)

(In Equation 1, Ro is a sensor resistance value which is a constant measured when the concentration of the individual gas is fixed under clean air conditions, Rs / Ro is a sensor resistance ratio, and i is an individual semiconductor gas sensor used for gas concentration measurement. The number assigned to, j is the number assigned to the individual gas to be measured, n is the total number of gases to be measured, G is the concentration of the individual gas to be measured, [G] _i is the individual gas to be measured The matrix consisting of the concentrations, k _ij is the rate of change of the sensor resistance ratio according to the change of the gas concentration having the j number in the semiconductor gas sensor having the i number, which is determined according to the gas of the j number in the semiconductor gas sensor having the i number, or The constant corrected from this, [k _ij ] ^-1 is the inverse matrix of the matrix consisting of k _ij when i and j change from 1 to n, respectively, [Log (Rs / Ro)] _i is i Changes from 1 to n For a matrix consisting of the logarithm of the sensor resistance ratio, a _ij is a minimum sensor resistance ratio value to measure the gas concentration with j number in the semiconductor gas sensor having an i number, in a semiconductor gas sensor having an i number determined by the number j of the gas or the corrected constant value therefrom, Σa _ij is the sum of the a _ij if the change in the fixed and in each i and j is 1, the number of n, [Σa _{ij] i} is the i Matrix consisting of ∑a _ij when changing from 1 to n.)

In exemplary embodiments of the present disclosure, the gas concentration measuring apparatus may further include a gas sensor device including a semiconductor gas sensor and the composite membrane structure spaced apart from the semiconductor gas sensor. The sensor resistance value Rs is obtained from the semiconductor gas sensor.

In the composite membrane structure according to the embodiments of the present invention, the insulating oil does not pass, but the gas in the oil may pass, and while the filtration differential pressure is very small, there is no degradation in mechanical strength. Furthermore, contamination due to moisture in the insulating oil medium and the insulating oil can be prevented.

The gas sensor device using the composite membrane structure together with a commercially available semiconductor gas sensor can be directly attached to the upper or lower portion of the transformer, so that the application or installation of the sensor is simple, so that the field application is convenient and very economical. . Therefore, when using the gas sensor device, there is no need to install an auxiliary mechanical device such as a vacuum pump for extracting the dissolved gas in the transformer containing the insulating oil.

In addition, the gas concentration measuring method and apparatus according to the embodiments of the present invention, when quantitatively measuring a plurality of types of gas concentrations mixed in the insulating oil for each type, it is necessary to select a specific semiconductor gas sensor that reacts only to a specific gas. Without difficulty, the concentration of each type of gas can be measured reliably and easily using a general-purpose semiconductor gas sensor.

As a result, it is possible to directly check on the spot whether an abnormality is occurring inside the transformer in operation and in which part within the transformer, and to predict the residual life of the insulating oil in the transformer. Of course, transformer maintenance can be performed economically and reliably.

1 is a schematic view showing a composite membrane structure according to one embodiment of the present invention.
2 is a schematic diagram showing a configuration of a gas sensor device according to an embodiment of the present invention.
3 is a schematic view showing a configuration of a gas sensor device according to another embodiment of the present invention.
4 is a schematic diagram illustrating an example in which a gas sensor device is mounted to a transformer in one embodiment of the present invention.
FIG. 5 is an exemplary graph showing a calibration of a sensor resistance measurement ratio measured for each kind of gas and concentration conditions mixed in a commercial semiconductor gas sensor used in one embodiment of the present invention.
FIG. 6 shows the molecular structure of a porous material layer formed in one embodiment of the present invention.
7 is a schematic view showing the configuration of a device fabricated to evaluate the effect of the composite membrane structure in an embodiment of the present invention.
8 is a graph illustrating a gas measurement result according to a change in carbon dioxide concentration using an electrochemical gas sensor according to an exemplary embodiment of the present invention.
FIG. 9 is a graph illustrating comparison of measured voltages of a gas measuring sensor with and without using a composite membrane structure under the same experimental conditions as in FIG. 8.

Hereinafter, a composite membrane structure for a gas sensor according to embodiments of the present invention, a gas sensor device using the same, and a gas concentration measuring method and apparatus using the same will be described in detail.

The use of low-cost, readily available, commercially available semiconductor gas sensors for quantitative real-time monitoring of dielectric oil degradation in power equipment such as transformers, for example, where oil can be used, is a significant replacement for conventional condition diagnosis technology. It has economic value.

However, in order to utilize a commercially available semiconductor gas sensor in quantitative real-time measurement of gas in dissolved oil in insulating oil, it is essential to use a separator for extracting and separating the dissolved gas together with a commercial semiconductor gas sensor. Silver hydrocarbon-based insulating oil medium cannot pass but low-molecular weight oils to be measured must be physically able to pass.

In addition, the separator may be applied to the oil in the direct contact with the insulating oil medium inside the transformer or in the empty space above the transformer so that it is not necessary to force the flow of the medium passing through the separator by applying a separate negative pressure. The pressure difference before and after the separator should be minimized.

In addition, the separator should increase the durability of the separator by reinforcing the mechanical strength of the separator even when the pressure difference is small.

Furthermore, the separator should be able to prevent the insulating oil medium and the moisture in the insulating oil from physically and chemically adhering to and contaminating the separator surface in terms of durability and reliability.

Accordingly, the present inventors have a composite membrane structure including a separator of insulating oil and dissolved gas used in conjunction with a semiconductor gas sensor, and after coating a porous material on the surface of a mesh mesh having a fine size first, and then again on the surface The present invention provides a composite membrane structure having a three-layered structure having a very small thickness and finally coating a material having pores small enough to penetrate only gases in oil generated from insulating oil.

1 is a schematic view showing a composite membrane structure according to one embodiment of the present invention.

As shown in FIG. 1, the composite membrane structure 5 according to one embodiment of the present invention includes a support 5a having a mesh, a coating layer 5b of porous material placed on the support and obtained by a sol-gel method. And a self-assembled monomolecular film 5c positioned in the coating layer of the porous material.

First, the self assembled monolayer 5c will be described. The self-assembled monolayer 5c has a structure in which a tail is attached to the head group and a functional group is attached to the end of the tail. Such self-assembled monolayers have a small molecular weight, such as a thickness of 1 μm to 10 μm, and a pore size of the material at a nanometer level (eg, 10 nm to 50 nm). Insulating oil medium is not permeable but gas in oil dissolved in the insulating oil can permeate.

In an exemplary embodiment, the self-assembled monolayer is one having oleophobic and hydrophobic at the same time. Thus, when the self-assembled monomolecular film is composed of oleophobic and hydrophobic, it is possible to prevent the deteriorated insulating oil medium and the moisture in the insulating oil from physically and chemically adhering to the separator surface and contaminating it.

Oleophobic and hydrophobic self-assembled monolayers are known in the art, and non-limiting examples of oleophobic and hydrophobic self-assembled monolayers include fluorinated hydrocarbon-based silanes.

As the fluorinated hydrocarbon silane, for example, 3M's Novec Coating EGC-1720 material, which is a transparent and low viscosity solution of a fluorosilane polymer dissolved in a hydrofluoroether solvent, may be used.

On the other hand, there are various inadequate problems when the self-assembled monolayer material is directly coated on the semiconductor gas sensor surface. In general, commercial semiconductor gas sensors have a heating wire embedded in the sensor to increase the measurement sensitivity of the sensor element, and the temperature is heated to heat the temperature. It is also required to reinforce the self-assembled monomolecular film material having a very thin thickness and weak mechanical strength.

Therefore, the mechanical strength of the self-assembled monomolecular film was reinforced as follows.

First, a support 5a having a mesh was formed at the bottom of the self-assembled monolayer 5c.

In an exemplary embodiment, the support having the mesh is a metal mesh net or a ceramic mesh net, and a metal mesh net may be used in that the manufacturing cost is low and the manufacturing is easy.

In a non-limiting example, the mesh spacing may be 1 μm to 100 μm in the horizontal and vertical directions, respectively, and the thickness of the support may be 0.05 mm to 1 mm.

In the case of reinforcing the strength with the support 5a having the mesh at the bottom as described above, it is not only easy to directly form the self-assembled monolayer 5c on the support 5a, but also needs to reinforce the strength.

Thus, a coating layer 5b of a porous material obtained by the sol-gel method is formed between the support 5a having the mesh and the self-assembled monolayer 5c so as to be located on the surface of the support 5a. The self-assembled monolayer 5c is coated on the coating layer 5b as described above.

The coating layer 5b of the porous material obtained by the sol-gel method is not only easy to form the self-assembled monolayer 5c, but also formed by the sol-gel method, that is, obtained by gelling the sol. Since the porous material is used, the pores of the self-assembled monolayer 5c have larger porosity than fine pores.

For reference, the sol-gel method refers to a process of making a colloidal state (sol) with a precursor and converting it into a liquid network (gel) through the gelation process of the sol to form an inorganic network. It is well known.

In an exemplary embodiment of the present invention, the porous material obtained by the sol-gel method, as a precursor, methyl trimethoxy silane (methyl trimethoxi silane), tetramethoxy silane (tetramethoxi silane), dimethyldimethoxi silane, tetraethoxysilane (tetraethoxi silane), methyl triethoxi silane (methyl triethoxi silane), dimethyldiethoxi silane, phenyl trimethoxyoxi silane, diphenyldimethoxysilane silane, phenyl triethoxi silane, diphenyldiethoxi silane, decyltrimethoxi silane, and isobutyltrimethoxi Above alkoxysilanes or M (OR) x [wherein M is a metal or metalloid such as titanium, zirconium, nickel, aluminum, lead, boron, etc., R is The polymer substance obtained by the sol-gel method using the sole or mixture of the alkoxy compound of a C1-C10 alkyl group is used. When the polymer material is used, durability, heat resistance and / or adhesion may be improved.

In a non-limiting example, the coating layer of the porous material may have a thickness of 10nm to 1,000nm.

Next, a gas sensor device including the above composite membrane structure will be described.

2 is a schematic view showing the configuration of a gas sensor device according to an embodiment of the present invention, FIG. 2A shows an exploded view of parts of the gas sensor device, FIG. 2B shows a fastening view of the parts shown in FIG. 2A, FIG. 2C shows a side cross-sectional view of the fastening of FIG. 2B.

As shown in FIG. 2A, in the gas sensor device according to the exemplary embodiment of the present invention, the semiconductor gas sensor 1 and the composite membrane structure 5 are formed at regular intervals from each other.

As described above, in general, since commercial semiconductor gas sensors have a heating wire embedded in the sensor and heated up to increase the measurement sensitivity of the sensor element, the composite membrane structure 5 is spaced apart from the semiconductor gas sensor 1 by a predetermined distance. In this way, a distance can be provided between the hot wire in the sensor and the composite membrane structure 5.

Specifically, the gas sensor device is a measuring device body that is accommodated (built in) in a cylindrical housing 2 in which the semiconductor gas sensor 1 serves as a body, and spaced apart from the semiconductor gas sensor 1 by a predetermined distance. The composite membrane structure 5 is attached to the upper end of (2). The semiconductor gas sensor 1 is supported by the lower plate 4, and the composite membrane structure 5 is covered by the upper plate 3. The upper plate 3 and the lower plate 4 are respectively fastened with the housing 2 by fastening means, for example flat head bolts 8, 9 (see FIG. 2B fastening view and FIG. 2C cross-sectional view).

On the semiconductor gas sensor 1 in the housing 4, for example, an o-ring, which is a member for sealing, may be provided.

In addition, one or both sides of the composite membrane structure 5 may be equipped with, for example, a silicon pad for gas sealing.

On the other hand, when a plurality of types of gas in the oil dissolved in the insulating oil is to be measured at the same time using a plurality of semiconductor gas sensors, by modifying the gas sensor device as shown in Figure 2 as shown in FIG. Different kinds of gas in oil can be measured.

3 is a schematic view showing the configuration of a gas sensor device according to another embodiment of the present invention, Figure 3a is an exploded view of parts of the gas sensor device, Figure 3b is a fastening of the parts shown in Figure 3a 3C shows a side cross-sectional view of the fastening of FIG. 3B.

In FIG. 3, a plurality of semiconductor gas sensors are arranged and bundled into an array 19, and one composite separator structure 21 is positioned on the array 19 of the sensors to form an integrated gas measuring device. Here, the composite membrane structure 21, as described above, the support 21a having a mesh, the coating layer 21b of the porous material by the sol-gel method formed on the support 21a, the coating layer of the porous material It has a structure of the self-assembly molecular film 21c formed on (21b).

The gas sensor device may include a first housing 15, which is a body accommodating (built in) the plurality of semiconductor gas sensor arrays 19, a second housing 20 on which the composite membrane structure is mounted, and the first housing. For example, an end cap 17 screwed into the lower portion of the 15 may be provided, and an adapter 23 fastened to the upper portion of the second housing 20. Here the adapter 23 is an adapter for connecting to the transformer.

A coupling 16, which is a connecting member, may be further provided between the end cap 17 and the first housing 15. The coupling 16 may be screwed to the first housing 15 and the end cap 17, respectively.

The first housing 15 and the second housing 20 may be screwed together. In addition, the second housing 20 and the adapter 23 may be fastened by fastening means, for example, a flat head bolt 24. The array 19 can also be fixed in the first housing by fastening means, for example flat head bolts 25.

Next, an example of measuring the gas concentration by attaching the gas sensor device to a transformer will be described.

4 is a schematic diagram illustrating an example in which a gas sensor device is mounted to a transformer in one embodiment of the present invention.

As shown in FIG. 4, the gas sensor device may perform sensing by contacting the insulating oil of the transformer or the vapor of the insulating oil.

Sensing can be carried out from the insulating oil of the transformer or from the vapor of the insulating oil.

Specifically, the gas sensor device 13, 13 ′ according to the embodiments of the present invention may be mounted on one side of the upper or lower side of the transformer body 14.

Since the insulating oil is not filled to the upper position inside the transformer 14 to maintain a constant empty space, when the oil in gas dissolved in the insulating oil is present in the space according to the insulating oil and gas in gas gas equilibrium conditions, It is advantageous to apply the gas sensor device 13 according to the embodiments. Here, the gate valve 10 for dissolving gas discharge is installed on the upper side of the transformer main body 14, and then the gas sensor device 13 is installed through the pipe socket 11 and the o-ring seal 12, It is possible to measure dissolved gas in water.

On the other hand, if the empty space as in the above case does not exist in the transformer main body 14, the dissolution gas discharge gate valve 10 'is provided on one side of the main body of the transformer main body 14, and the pipe socket After passing through the 11 'and the o-ring seals 12', the gas sensor device 13 'can be installed to directly measure the gas in the oil dissolved in the insulating oil in direct contact with the insulating oil medium.

Next, a gas concentration measuring method and apparatus according to embodiments of the present invention will be described in detail.

In order to utilize a commercially available semiconductor gas sensor in quantitative real-time measurement of gas in dissolved oil in insulating oil, there should be no difficulty in selecting a specific semiconductor gas sensor that represents a sensor output value in response to only a specific gas. Indeed, commercially available semiconductor gas sensors do not respond to hydrogen alone, for example, to provide a sensor output value, but instead to all mixed dissolved gases, one sensor output value is produced.

As such, a gas sensor device can be economically implemented only when a general-purpose semiconductor gas sensor capable of displaying a sensor output value in response to various kinds of gas components can be used. In addition, when using such a general-purpose semiconductor gas sensor, it should be possible to measure the concentration of each type of gas with high reliability and easy.

Therefore, in the embodiments of the present invention, the concentration of the mixed gas of the plurality of components dissolved in the insulating oil is independently determined for each gas type based on each measured value measured by the plurality of semiconductor gas sensors measuring the gas mixed in the insulating oil. To calculate.

To this end, a plurality of general-purpose gas sensors having the same number of dissolved gas types are mixed in a plurality of types in the insulating oil and used in parallel, and consist of proportional constants of sensor resistance ratio and gas concentration of the plurality of used gas sensors. The inverse matrix of the matrix can be calculated and mixed in the insulating oil to independently determine the type and concentration of dissolved gases.

That is, in the embodiments of the present invention, the sensor resistance value (Rs) is obtained by sensing the dissolved gas of the insulating oil with one or more semiconductor gas sensors, and the above-described equation (1) is obtained from the resistance value (Rs) thus obtained. It is possible to obtain the individual gas concentration in the dissolved gas of the insulating oil.

[Equation 1]

[G] _i = [k _ij ] ^-1 [[Log (Rs / Ro)] _i- [∑a _ij ] _i ] (i, j = 1 ~ n)

(In Equation 1, Ro is a sensor resistance value which is a constant measured when the concentration of an individual gas is fixed at 1000 ppm, for example, under clean air conditions, Rs / Ro is a sensor resistance ratio, and i is an individual used for measuring the gas concentration. The number assigned to the semiconductor gas sensor, j is the number assigned to the individual gas for which the gas concentration is to be measured, n is the total number of gases to be measured, G is the concentration of the individual gas to be measured, and [G] _i is the measurement target. The matrix consisting of individual gas concentrations, k _ij, is the rate of change of the sensor resistance ratio according to the gas concentration change having the j number in the semiconductor gas sensor having the i number, and the gas number of the j number in the semiconductor gas sensor having the i number. The constant value, determined from or corrected from it, [k _ij ] ^-1 is the inverse matrix of the matrix consisting of k _ij when i and j vary from 1 to n, respectively, [Log (Rs / Ro)] _i is in the 1 n i As a matrix, a _ij is the minimum sensor resistance which can measure the gas concentration with j number in the semiconductor gas sensor having an i number ratio value consisting of the logarithm of the sensor resistance ratio in the case of changing the number, with i number In the semiconductor gas sensor, a constant value determined by or corrected from the gas of j number, ∑a _ij is the sum of a _ij when i is fixed and j changes from 1 to n, respectively, [∑a _ij ] _i is a matrix of ∑a _ij where i changes from 1 to n)

For reference, in the present specification, the k _ij value or the a _ij value is a calibration value according to a semiconductor sensor provided from a semiconductor sensor provider (see FIG. 5 to be described later). The value may be obtained by additionally correcting the calibration value, as described below, when using a semiconductor sensor according to embodiments of the present invention. Accordingly, the k _ij value, or a _ij value, are constant values determined or corrected according to the gas of the j number in the semiconductor gas sensor having the i number.

In addition, the Ro value is a known sensor resistance value, that is, a sensor resistance constant value measured when the concentration of the individual gas is fixed, for example, when the concentration of the individual gas is fixed at 1000 ppm under clean air conditions.

In example embodiments, the gas concentration measuring method may use the semiconductor gas sensor in the gas sensor device including the semiconductor gas sensor and the composite separator structure as described above, which is spaced apart from the semiconductor gas sensor. .

In addition, in the embodiments of the present invention, at least one semiconductor gas sensor and a sensor resistance value (Rs) obtained by sensing the dissolved gas of the insulating oil from the semiconductor gas sensor, the individual of the dissolved gas of the insulating oil according to [Equation 1]. By the gas concentration measuring device including a computing device for obtaining the gas concentration, the concentration of the gases mixed and dissolved in the insulating oil can be quantitatively measured for each type.

Also in the gas concentration measuring apparatus, in the exemplary embodiments, the gas concentration measuring apparatus further comprises a gas sensor device including a semiconductor gas sensor and the composite membrane structure spaced apart from the semiconductor gas sensor. Of course, the sensor resistance value (Rs) can be obtained from the semiconductor gas sensor of the gas sensor device.

In order to explain the above Equation 1, for the sake of understanding, the number of sensors is five (ie i = 1, 2, 3, 4, 5), and the type of gas is five (ie , j = 1, 2, 3, 4, 5). The method of the embodiments of the present invention thus makes the number i of the semiconductor gas sensors equal to the number j of objects to be measured.

These five gases are dissolved in, for example, hydrogen (H ₂ ), carbon dioxide (CO), acetylene (C ₂ H ₂ ), ethylene (C ₂ H ₄ ), and methane (CH ₄ ) gases in a transformer insulating oil. It is assumed to exist. In addition, for convenience of understanding, it is assumed that a semiconductor gas sensor uses a commercially available semiconductor gas sensor in which the sensor output resistance Rs according to the concentration condition for each gas type is measured as shown in FIG. 5, for example.

FIG. 5 is an exemplary graph showing a calibration of a sensor resistance measurement ratio measured for each kind of gas and concentration conditions mixed in a commercial semiconductor gas sensor used in one embodiment of the present invention. In FIG. 5, the x-axis is concentration (ppm) and the y-axis is sensor resistance ratio (Rs / Ro). Here, Ro represents a sensor resistance value measured when the concentration for each gas type is fixed at 1,000 ppm, for example, under a clean air condition in which no other gas is measured, and Rs is a resistance value measured by the sensor under an arbitrary gas concentration condition. . Therefore, Rs / Ro denotes a sensor measurement resistance ratio in which the resistance value measured by the sensor under a certain gas concentration condition is compared with the resistance value measured under clean air. For reference, a graph according to the concentration change with respect to the sensor measurement resistance ratio is typically provided as calibration data by semiconductor gas sensor providers when purchasing a semiconductor gas sensor. Thus, the Ro value, k _ij value or a _ij value used for the calculations in the embodiments of the present invention are already predetermined constant values.

If five kinds of gases are mixed and dissolved in the insulating oil, and if a total of five kinds of semiconductor gas sensors are used to measure the concentration of each of these mixed gases, five kinds of gases are used in one gas sensor S1 of the gas sensors. The sensor resistance ratio (Rs / Ro) _S1 measured from these sensors is linearly added to the sensor resistance ratio values measured from respective gas components and concentration conditions, which can be expressed by Equation 2 below.

&Quot; (2) "

Log (Rs / Ro) _s1 = [k ₁₁ log (H ₂ , ppm) + a ₁₁ ] + [k ₁₂ log (CO, ppm) + a ₁₂ ] + [k ₁₃ log (C ₂ H ₂ , ppm) + a ₁₃ ] + [k ₁₄ log (C ₂ H ₄ , ppm) + a ₁₄ ] + [k ₁₅ log (CH ₄ , ppm) + a ₁₅ ]

In Equation 2, K ₁₁ represents a sensor resistance ratio change rate (slope of a straight line) according to the change of the hydrogen gas concentration [(H ₂ , ppm)] in the sensor 1.

a ₁₁ represents the minimum log (sensor resistance ratio) value at which sensor 1 can measure the hydrogen gas concentration [(H ₂ , ppm)].

K ₁₂ represents the change rate of the sensor resistance ratio according to the change of the carbon monoxide gas concentration ((CO, ppm)] in the sensor 1.

a ₁₂ represents the minimum log (sensor resistance ratio) value at which sensor 1 can measure the carbon monoxide gas concentration [(CO, ppm)].

K ₁₃ represents the change rate of the sensor resistance ratio according to the change in the acetylene gas concentration [(C ₂ H ₂ , ppm)] in the sensor 1.

a ₁₃ represents the minimum log (sensor resistance ratio) value at which sensor 1 can measure the acetylene gas concentration [(C ₂ H ₂ , ppm)].

K ₁₄ represents the change rate of the sensor resistance ratio according to the change of the ethylene gas concentration [(C ₂ H ₄ , ppm)] in the sensor 1.

a ₁₄ represents the minimum log (sensor resistance ratio) value at which sensor 1 can measure the ethylene gas concentration [(C ₂ H ₄ , ppm)].

K ₁₅ represents the change rate of the sensor resistance ratio according to the change of the methane gas concentration [(CH ₄ , ppm)] in the sensor 1.

a ₁₅ represents the minimum log (sensor resistance ratio) value at which sensor 1 can measure the methane gas concentration [(CH ₄ , ppm)].

For reference, as shown in FIG. 5, the above values may be respectively obtained from sensor calibration data provided from a general-purpose semiconductor gas sensor provider. If the type of gas exemplified above is not specified in the calibration data provided, the values of k and a corresponding to the relevant gas type may be zero.

As shown in Equation 2, the sensor resistance ratios measured by the different types of gas sensors S2, S3, S4, and S5 sensors may be expressed as shown in the following equations.

&Quot; (3) "

Log (Rs / Ro) _s2 = [k ₂₁ log (H ₂ , ppm) + a ₂₁ ] + [k ₂₂ log (CO, ppm) + a ₂₂ ] + [k ₂₃ log (C ₂ H ₂ , ppm) + a ₂₃ ] + [k ₂₄ log (C ₂ H ₄ , ppm) + a ₂₄ ] + [k ₂₅ log (CH ₄ , ppm) + a ₂₅ ]

&Quot; (4) "

Log (Rs / Ro) _s3 = [k ₃₁ log (H ₂ , ppm) + a ₃₁ ] + [k ₃₂ log (CO, ppm) + a ₃₂ ] + [k ₃₃ log (C ₂ H ₂ , ppm) + a ₃₃ ] + [k ₃₄ log (C ₂ H ₄ , ppm) + a ₃₄ ] + [k ₃₅ log (CH ₄ , ppm) + a ₃₅ ]

&Quot; (5) "

Log (Rs / Ro) _s4 = [k ₄₁ log (H ₂ , ppm) + a ₄₁ ] + [k ₄₂ log (CO, ppm) + a ₄₂ ] + [k ₄₃ log (C ₂ H ₂ , ppm) + a ₄₃ ] + [k ₄₄ log (C ₂ H ₄ , ppm) + a ₄₄ ] + [k ₄₅ log (CH ₄ , ppm) + a ₄₅ ]

&Quot; (6) "

Log (Rs / Ro) _s5 = [k ₅₁ log (H ₂ , ppm) + a ₅₁ ] + [k ₅₂ log (CO, ppm) + a ₅₂ ] + [k ₅₃ log (C ₂ H ₂ , ppm) + a ₅₃ ] + [k ₅₄ log (C ₂ H ₄ , ppm) + a ₅₄ ] + [k ₅₅ log (CH ₄ , ppm) + a ₅₅ ]

Equations 2 to 6 may be simply expressed in a matrix form as shown in Equation 7 as follows.

[Equation 7]

Equation 7 is expressed using Equation 8 by using an index code.

[Equation 8]

[Log (Rs / Ro)] _{s i} = [k _ij ] [G (ppm)] _i + [∑a _ij ] _{i (i, j = 1..5)}

Therefore, the concentration of each gas ([G (ppm)] _i, i = 1,5 ) which is dissolved in the insulating oil in a complex manner can be finally calculated and calculated as shown in [Equation 9].

&Quot; (9) "

[G (ppm)] _i = [k _ij ] ^-1 [[Log (Rs / Ro)] _i- [∑a _ij ] _i ] _{(i, j = 1..5)}

In Equations 8 and 9, as described above, Ro is a sensor resistance value, Rs / Ro, which is a constant measured when the concentration of an individual gas is fixed at 1000 ppm, for example, under clean air conditions. The resistance ratio, i, is the number assigned to the individual semiconductor gas sensor used for the gas concentration measurement, and j is the number assigned to the individual gas for which the gas concentration measurement is desired. Here, i = j = 1-5. G is the individual gas concentration (in ppm), [G] _i is a matrix composed of individual gas concentrations to be measured, and k _ij is a sensor according to the gas concentration change having a j number in a semiconductor gas sensor having an i number. As the rate of change in the resistance ratio, the constant values, [k _ij ] and [k _ij ] ⁻¹ , determined from or corrected according to the gas of the j number in the semiconductor gas sensor having the i number, indicate that i and j are 1 to 5, respectively. Matrix consisting of k _ij when changing to a number and its inverse matrix, [Log (Rs / Ro)] _i is a matrix consisting of the logarithmic value of the sensor resistance ratio when i changes from 1 to 5, a _ij is the minimum sensor resistance ratio value for measuring the gas concentration with j number in the semiconductor gas sensor with i number, and is a constant determined or corrected according to the gas of j number in the semiconductor gas sensor with i number. Value, ∑a _ij is The sum of a _ij when i is fixed and j changes from 1 to 5, respectively. [∑a _ij ] _i is a matrix consisting of ∑a _ij when i changes from 1 to 5;

In this way, the concentration of each of the gas that is dissolved by mixing in the insulating oil is the inverse of the matrix ([k]) which is composed of a proportional constant in the sensor resistance ratio and the gas concentration of the gas sensor matrix (Inverse Matrix, [k] ^{- It} can be found by basically calculating ¹ ).

For reference, the inverse matrix may be obtained using a mathematical algorithm such as Gaussian elimination or simply calculated using commercial software (eg Matlab), and such a calculation method or software may be performed in the art. As is well known in the art, the computing device of embodiments of the present invention may include a processor or computer using the software.

On the other hand, if there is an additional gas type other than the gas type exemplified above in the calibration data provided from the semiconductor gas sensor provider (i.e., i = j> 5), Equation 9 matches i = j accordingly. The formula can be expanded to show

In this case, i = j = 1 to n is the equation [1] as described above.

As described above, in the method and apparatus for measuring the gas concentration, there is no difficulty in selecting a specific semiconductor gas sensor that reacts only to a specific gas when quantitatively measuring a plurality of types of gas concentrations mixed and dissolved in the insulating oil. It is possible to measure the concentration of each type of gas reliably and easily by using a general-purpose semiconductor gas sensor easily, without placing any limitation on the selection of the semiconductor gas sensor.

Hereinafter, embodiments of the present invention will be described in more detail with reference to examples. However, the following examples are described for illustrative purposes and are not intended to limit the scope of the invention.

Composite Membrane Structure Manufacturing

As one embodiment of the present invention, a composite membrane structure as shown in FIG. 1 was prepared.

First, a dense lattice mesh mesh 5a of stainless material having a mesh thickness of 0.1 mm and a mesh size of 4 μm in width and length was used as a mesh having a mesh.

If the self-assembled monomolecular film 5c, which is a separation material of oil and gas, is directly coated on the metal mesh net 5a, pores of very fine size and a dense permeable membrane cannot be obtained. Therefore, the porous material coating layer 5b obtained by the sol-gel method of the crude size is formed primarily on the surface of the metal mesh net 5a.

The process of forming the porous material coating layer 5b will be described, for example, as follows.

The silicon alkoxide, a sphere, is hydrolyzed to form a silicon hydroxide, whereby the hydroxyl groups (-OH) in the resulting molecules react with each other to form a polymerized sol. For reference, the hydrolysis reaction is as follows.

[Reaction Scheme 1]

= Si-OR + H ₂ O-> = Si-OH + R-OH

At this time, the gelation proceeds as silicon oxides are connected in a three-dimensional structure depending on the reaction atmosphere during the condensation polymerization. For reference, the condensation polymerization reaction is as follows.

[Reaction Scheme 2]

≡Si-OH + ≡Si-OH-> ≡Si-OH + H ₂ O

≡Si-OH + ≡Si-OR-> ≡Si-OH + ROH

Complete gelation is carried out during the heat treatment process after the prepared organic modified hybrid sol-gel material is applied to the surface of the support having a mesh, and is naturally formed according to the formation of the three-dimensional structure between molecules in the process of gelation, fine pores Will have

As a more specific embodiment, the synthesis of the organic modified hybrid sol-gel proceeds as follows.

Methyltrimethoxy Silane (MTMOS), tetramethoxy silane (TEOS) as the silicon-based alkoxide precursor, and 3-Methacryloxy propyl trimethoxy silane (MEMOS) as the organomodified silane precursor were 5: 4: 1 After mixing in a molar ratio, the mixture was mixed with a mixture of methanol and isopropyl alcohol (IPA) in the same weight ratio (1: 1) and placed in a three-necked round flask equipped with a condenser and a thermometer. Stirring was continued using a bar magnet for minutes. Then, as a reaction catalyst, deionized water adjusted to an acid concentration (pH) of about 3 to 4 with a concentrated phosphoric acid of 98% or more in a 1: 1 mixed solution of 20 g of methanol and isopropyl alcohol was added with the silane precursor to 2: 1 ( The catalyst solution mixed in a molar ratio of H ₂ O: alkoxide) was slowly added dropwise using a dropping funnel, followed by a reaction for about 2 hours while maintaining the temperature of 30 ° C. under continuous stirring. It was. The unit molecular structure of the organic modified hybrid membrane thus obtained is shown in FIG. 6.

In order to prevent contamination and permeation from impurities such as oil, water, dust, and the like on the surface of the porous material coating layer 5b thus prepared, and to increase the permeability of the gas in oil dissolved in the insulating oil, oleophobicity and hydrophobicity are increased. A self-assembled monomolecular film was again coated with a combined fluorinated hydrocarbon silane (EGC-1720, available from 3M) to prepare a composite membrane structure.

Evaluation of Composite Membrane Structure

In order to verify the effect of the composite membrane structure in this embodiment, the following test was performed.

7 is a schematic view showing the configuration of a device fabricated to evaluate the effect of the composite membrane structure in an embodiment of the present invention.

As shown in FIG. 7, a pressure vessel 30 containing carbon dioxide gas is connected to a transparent hermetic acrylic box 26 having a constant volume, and the pressure regulator 31 and the opening / closing valve 32 are opened to open the box 26. Into the carbon dioxide at the proper concentration and shut the valve (32).

In the box 26, a gas sensor device in which the manufactured composite membrane structure is assembled together with a semiconductor carbon dioxide gas sense (trade name MG811, manufactured by Hanwei Electronics Co., Ltd., trade name MG811) as shown in FIG. 2 (Example Gas Sensor Apparatus), and in order to prepare for this, a gas sensor apparatus (comparative example gas sensor apparatus) except for the composite membrane structure in the same gas sensor apparatus was assembled at positions 27 and 28, respectively.

Then, another gas discharge switching valve 33 attached to the box is opened finely to compare and measure the results of the two types of gas sensor devices 27 and 28 under environmental conditions in which the concentration of carbon dioxide in the sealed box is gradually reduced. It was.

On the other hand, in order to quantitatively compare and measure the carbon dioxide content under the test conditions, a commercially used electrochemical carbon dioxide gas measurement sensor 29 is incorporated in the box 26 and the carbon dioxide content that decreases with time is measured.

8 is a graph illustrating a gas measurement result according to a change in carbon dioxide concentration using an electrochemical gas sensor according to an exemplary embodiment of the present invention. In FIG. 8, the x axis is time (seconds) and the y axis is carbon dioxide concentration (ppm).

As shown in FIG. 8, the concentration of carbon dioxide gas initially injected into the box 26 gradually decreased over time as the valve 29 was opened.

FIG. 9 is a graph illustrating comparison of measured voltages of a gas measuring sensor with and without using a composite membrane structure under the same experimental conditions as in FIG. 8. In FIG. 9, the x axis is time (seconds) and the y axis is sensor output voltage (volts).

It can be seen that the gas sensor device of the embodiment shows a relatively larger output value than the gas sensor device of the comparative example, which means that the amount of carbon dioxide gas content measured in the gas sensor device in which the composite membrane structure is integrally assembled It means that it is measured a little smaller than the carbon dioxide gas content present in the.

Although the membrane is fine, it can be seen that it acts as a kind of resistance factor in gas measurement. However, since the membrane has an even and uniformly insignificant effect over the entire range of carbon dioxide content tested, the resistance effect is considered in advance. The resistance ratio characteristic calibration data (k _ij value or a _ij value) of the commercially available semiconductor gas sensors of the gas sensor device, in which the composite membrane structure is assembled together, is corrected by the user through a second calibration experiment to remove and use the resistance factor. Can be.

Although the present invention has been described above with reference to exemplary embodiments, it will be apparent to those skilled in the art that various changes in details can be made without departing from the scope of the invention as set forth in the claims. It can be understood.

1: semiconductor gas sensor 2: housing
3: upper plate 4: lower plate
5: composite membrane structure
5a: support with mesh
5b: porous material layer by sol-gel method
5c: self-assembled monolayer
6: Pad for gas seal 7: O-ring seal member
8, 9: flat plate head bolt
10, 10 ': gate valve for dissolving gas
11, 11 ': pipe socket
12, 12 ': O-ring seal
13, 13 ': gas sensor device
14: transformer body 15: first housing
16: coupling 17: end cap
18: o-ring seal member 19: semiconductor gas sensor array
20: second housing 21: pad for gas seal
22: composite membrane structure 22a: support having a mesh
22b: porous material layer formed by sol-gel method
22c: self-assembled monolayer 23: adapter
24, 25: flat plate head bolt
26: test box
27: gas sensor device in which the composite membrane structure is assembled
28: Gas sensor device with no composite membrane structure assembled
29: Electrochemical Gas Measurement Sensor
30: carbon dioxide pressure vessel
31: pressure regulator
32: on-off valve for gas injection
33: on-off valve for gas discharge

Claims (4)

Sensing the dissolved gas of the insulating oil with at least one semiconductor gas sensor to obtain a sensor resistance value Rs; And
Obtaining the individual gas concentration in the dissolved gas of the insulating oil from the obtained resistance value (Rs) by the following Equation (1).
[Equation 1]
[G] _i = [k _ij ] ^-1 [[Log (Rs / Ro)] _i- [∑a _ij ] _i ] (i, j = 1 ~ n)
(In [Equation 1], Ro is a sensor resistance value which is a constant measured when fixing the concentration of an individual gas, Rs / Ro is a sensor resistance ratio, i is a number assigned to an individual semiconductor gas sensor used for gas concentration measurement. where j is the number assigned to the individual gas to be measured, n is the total number of gases to be measured, G is the concentration of the individual gas to be measured, and [G] _i is the individual gas concentration to be measured. K _ij is the rate of change of the sensor resistance ratio according to the gas concentration change having the j number in the semiconductor gas sensor having the i number. The constant value [k _ij ] ^-1 is the inverse matrix of the matrix consisting of k _ij where i and j vary from 1 to n, respectively, and [Log (Rs / Ro)] _i is i from 1 to n Of sensor resistance ratio As a matrix, a _ij is the minimum sensor resistance which can measure the gas concentration with j number in the semiconductor gas sensor having an i number ratio value consisting geugap, determined by the gas in j number in the semiconductor gas sensor having an i number ∑a _ij is the sum of a _ij where i changes from 1 to n, and [∑a _ij ] _i changes i from 1 to n Is a matrix consisting of ∑a _ij ) The method of claim 1,
The gas concentration measuring method uses a semiconductor gas sensor in a gas sensor device including a semiconductor gas sensor and a composite separator structure positioned to be spaced apart from the semiconductor gas sensor.
The composite membrane structure is a support having a mesh structure; A coating layer of a porous material placed on the support and obtained by a sol-gel method; And a self-assembled monomolecular film positioned on the coating layer of the porous material. One or more semiconductor gas sensors; And
A computing device that obtains individual gas concentrations in the dissolved gas of the insulating oil according to Equation 1 below from a sensor resistance value Rs obtained by sensing the dissolved gas of the insulating oil from the semiconductor gas sensor. Concentration measuring device.
[Equation 1]
[G] _i = [k _ij ] ^-1 [[Log (Rs / Ro)] _i- [∑a _ij ] _i ] (i, j = 1 ~ n)
(In [Equation 1], Ro is a sensor resistance value which is a constant measured when fixing the concentration of an individual gas, Rs / Ro is a sensor resistance ratio, i is a number assigned to an individual semiconductor gas sensor used for gas concentration measurement. where j is the number assigned to the individual gas to be measured, n is the total number of gases to be measured, G is the concentration of the individual gas to be measured, and [G] _i is the individual gas concentration to be measured. K _ij is the rate of change of the sensor resistance ratio according to the gas concentration change having the j number in the semiconductor gas sensor having the i number. The constant value [k _ij ] ^-1 is the inverse matrix of the matrix consisting of k _ij where i and j vary from 1 to n, respectively, and [Log (Rs / Ro)] _i is i from 1 to n Of sensor resistance ratio As a matrix, a _ij is the minimum sensor resistance which can measure the gas concentration with j number in the semiconductor gas sensor having an i number ratio value consisting geugap, determined by the gas in j number in the semiconductor gas sensor having an i number ∑a _ij is the sum of a _ij where j changes from 1 to n, and [∑a _ij ] _i is the value i changes from 1 to n Is a matrix consisting of ∑a _ij ) The method of claim 3, wherein
The gas concentration measuring device includes a gas sensor device including a semiconductor gas sensor and a composite membrane structure spaced apart from the semiconductor gas sensor,
The composite membrane structure is a support having a mesh structure; A coating layer of a porous material placed on the support and obtained by a sol-gel method; And a self-assembled monomolecular film positioned on the coating layer of the porous material.
And a sensor resistance value (Rs) is obtained from the semiconductor gas sensor of the gas sensor device.

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