Converter transformer residual magnetism detection sensor and preparation method thereof

Abstract

The invention belongs to the technical field of power equipment, and discloses a converter transformer residual magnetism detection sensor and a preparation method thereof. The converter transformer residual magnetism detection sensor comprises a shell, a pressure sensor and an adsorption block, the pressure sensor and the adsorption block are packaged in the shell; the shell is made of a non-ferromagnetic material, and the adsorption block is made of a ferromagnetic material; the pressure sensor is a flexible pressure sensor, and the flexible pressure sensor comprises a dielectric layer and electrode layers arranged on the two sides of the dielectric layer respectively; the converter transformer residual magnetism detection sensor is used for being installed on a transformer oil tank, the pressure sensor is located between an iron core of a converter transformer and an adsorption block, the adsorption block is used for compressing the pressure sensor under the action of residual magnetism in the iron core, and the pressure sensor is used for outputting a pressure value signal under compression of the adsorption block. The technical scheme disclosed by the invention can be used for detecting the residual magnetism of the converter transformer, and has relatively high residual magnetism detection precision and accuracy.

Description

Technical Field

[0001] The invention belongs to the technical field of electric power equipment, and in particular relates to a converter transformer residual magnetism detection sensor and a preparation method thereof. Background Art

[0002] Ultra-high voltage direct current transmission technology has the characteristics of large capacity, low loss and saving of line corridors. It is an economical and efficient way of transmission. The converter transformer is the core equipment of the ultra-high voltage direct current transmission system, which directly affects the safe and reliable operation of the entire direct current transmission system. When the converter transformer is out of operation and after the DC resistance test of the converter transformer, residual magnetism will be generated in the converter transformer. If it is put into operation in this state, excitation surge current and overvoltage will be generated, which will seriously threaten the safety of the power grid system and power equipment. Therefore, before the converter transformer is put into operation, the residual magnetism must be eliminated.

[0003] The existing demagnetization methods for converter transformers mainly include DC method, industrial frequency AC method and low frequency AC method. When eliminating the residual magnetism in the converter transformer, it is generally necessary to detect the residual magnetism in the converter transformer first; however, the converter transformer is a complex combination of stray capacitance and linear / nonlinear inductance, and depending on the external load conditions, during and after the excitation is removed, the core still has complex magnetic processes, resulting in unreliable residual magnetism detection results, which in turn affects the demagnetization effect. Summary of the invention

[0004] The object of the present invention is to provide a converter transformer residual magnetism detection sensor and a preparation method thereof to solve one or more of the above-mentioned technical problems. The technical solution provided by the present invention can detect the residual magnetism of the converter transformer and has high residual magnetism detection precision and accuracy.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a converter transformer residual magnetism detection sensor, comprising: a housing, a pressure sensor and an adsorption block; The pressure sensor and the adsorption block are both encapsulated in the shell, one side of the pressure sensor is connected to the inner wall of the shell, and the adsorption block is arranged on the other side of the pressure sensor; The shell is made of non-ferromagnetic material, and the adsorption block is made of ferromagnetic material; The pressure sensor is a flexible pressure sensor, and the flexible pressure sensor comprises a dielectric layer and electrode layers respectively arranged on both sides of the dielectric layer; Among them, the converter transformer residual magnetism detection sensor is used to be installed on the transformer oil tank, the pressure sensor is located between the iron core of the converter transformer and the adsorption block, the adsorption block is used to compress the pressure sensor under the action of the residual magnetism in the iron core, and the pressure sensor is used to output a pressure value signal under the compression of the adsorption block.

[0006] A further improvement of the present invention is that The housing comprises a base and a cover, wherein the cover is detachably mounted on the base; The pressure sensor is provided with a signal line, and the signal line is used to output the pressure value signal; The base is provided with a threading hole, through which the signal line of the pressure sensor extends out of the housing, and a sealing material is filled between the signal line and the threading hole; The base is provided with a guide column, the adsorption block is provided with a guide hole, and the adsorption block is sleeved and installed on the guide column through the guide hole.

[0007] A further improvement of the present invention is that An electric field shielding layer is arranged on the outer side of the shell.

[0008] A further improvement of the present invention is that The shell is in a negative pressure environment.

[0009] A further improvement of the present invention is that An arc-shaped convex structure is formed on the surface of the dielectric layer of the flexible pressure sensor.

[0010] A further improvement of the present invention is that it also includes: The calculation terminal is used to obtain the pressure value signal output by the pressure sensor, and calculate the amount of residual magnetism in the iron core of the converter transformer based on the pressure value signal.

[0011] The present invention provides a method for preparing a converter transformer residual magnetism detection sensor, comprising the following steps: Prepare a pressure sensor, attach an adsorption block to the pressure sensor, and package the pressure sensor and the adsorption block into a housing; The steps of preparing the pressure sensor include: adding a dielectric material dispersion into a polydimethylsiloxane dispersion to obtain a mixed solution; adding sodium chloride to the mixed solution, heating and stirring to form a colloid, adding a curing agent to the colloid, stirring evenly and applying it to a mold, drying and curing to obtain a film; placing the obtained film in deionized water for washing to remove the sodium chloride to obtain a porous film; and encapsulating the porous film between two electrode layers to prepare a pressure sensor.

[0012] A further improvement of the present invention is that The dielectric material is a mixture of one or both of carbon nanotubes and carbon black.

[0013] A further improvement of the present invention is that The specific steps of packaging the pressure sensor and the adsorption block into the housing include: Assembling the pressure sensor and the adsorption block into the housing, wherein one end surface of the pressure sensor is connected to the inner wall of the housing, and the other end surface of the pressure sensor is connected to the adsorption block; The shell is subjected to vacuum hole processing, and the shell is sealed after a negative pressure environment is formed inside the shell.

[0014] A further improvement of the present invention is that The surface of the mold is provided with wavy microgrooves, and the wavy microgrooves are used to form an arc-shaped convex structure on the surface of the dielectric layer.

[0015] Compared with the prior art, the present invention has the following beneficial effects: In the converter transformer residual magnetism detection sensor provided by the present invention, the pressure sensor and the adsorption block of ferromagnetic material are encapsulated in a shell, and the adsorption block can compress the pressure sensor based on the residual magnetism effect, and the amount of iron core residual magnetism can be determined by the pressure value signal output by the pressure sensor under compression, thereby realizing the detection of the residual magnetism of the converter transformer and having a high residual magnetism detection accuracy. Specifically, encapsulating the pressure sensor and the adsorption block in the shell avoids the influence of the oil pressure change of the transformer oil on the sensor, and ensures the accuracy of the sensor detection; further, the improvement of the residual magnetism detection accuracy of the converter transformer is conducive to the improvement of the residual magnetism elimination accuracy of the converter transformer, and can improve the safety of the converter transformer when in use.

[0016] In the present invention, the threading hole opened on the base is convenient for leading out the signal line while maintaining the integrity of the shell; the sealing material is filled between the signal line and the threading hole, which effectively prevents transformer oil or other impurities from entering the shell, ensuring the long-term stable operation of the sensor; the guide column on the base cooperates with the guide hole on the adsorption block to provide a stable guide for the adsorption block, ensuring the accurate displacement of the adsorption block under the action of the magnetic field.

[0017] In the present invention, the electric field shielding layer arranged outside the shell can effectively shield the influence of the external electric field on the sensor, thereby improving the anti-interference ability of the detection; in addition, the electric field shielding layer also provides an additional layer of protection for the sensor, thereby extending the service life of the sensor.

[0018] In the present invention, the interior of the shell is a negative pressure environment, which eliminates the influence of the internal air on the action of the adsorption block and the detection accuracy of the pressure sensor, thereby improving the detection accuracy of the overall sensor.

[0019] In the present invention, an arc-shaped convex structure is formed on the surface of the dielectric layer, so that the pressure sensor is very easy to be compressed, thereby greatly improving the sensitivity of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below; obviously, the drawings described below are some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 1 is an exploded schematic diagram of a converter transformer residual magnetism detection sensor in an embodiment of the present invention; Figure 2 yes Figure 1 A schematic diagram of the appearance of the embodiment shown; Figure 3 yes Figure 1 a schematic cross-sectional view of the illustrated embodiment; The explanation of the reference numerals in the figures is as follows: 1. Shell; 11. Base; 111. Threading hole; 12. Cover; 13. Guide column; 2. pressure sensor; 21. dielectric layer; 22. electrode layer; 23. signal line; 3. Adsorption block. DETAILED DESCRIPTION

[0022] In order to make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments and technical solutions are only part of the embodiments of the present invention, not all of the embodiments.

[0023] All other embodiments obtained by those of ordinary skill in the art without creative work based on the technical solutions disclosed in the embodiments of the present invention belong to the scope of protection of the present invention. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device including a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] See also Figures 1 to 3The embodiment of the present invention provides a converter transformer residual magnetism detection sensor, which can be installed in a transformer oil tank, and includes: a shell 1, a pressure sensor 2 and an adsorption block 3; wherein the shell 1 is made of non-ferromagnetic material, the pressure sensor 2 is a flexible pressure sensor, and the adsorption block 3 is made of ferromagnetic material; the pressure sensor 2 and the adsorption block 3 are both encapsulated in the shell 1, one end face of the pressure sensor 2 is connected to the inner wall of the shell 1, and the other end face of the pressure sensor 2 is connected to the adsorption block 3; In a specific exemplary technical scheme, the shell 1 includes a base 11 and a cover 12, and a threading hole 111 is opened on the base 11, and the signal line 23 provided in the pressure sensor 2 extends out of the shell 1 through the threading hole 111, and the space between the signal line 23 and the threading hole 111 is filled with sealing material; in a further preferred technical scheme, a guide column 13 is provided on the base 11, and a guide hole is opened on the adsorption block 3, and the adsorption block 3 is mounted on the guide column 13 through the guide hole; an electric field shielding layer is provided on the outside of the shell 1; the shell 1 is in a negative pressure environment; the flexible pressure sensor includes a dielectric layer 21 and an electrode layer 22 arranged on both sides of the dielectric layer 21.

[0025] In the technical solution provided by the embodiment of the present invention, the pressure sensor and the adsorption block of ferromagnetic material are encapsulated in a shell to form a new type of residual magnetism detection device. The device uses the adsorption effect of residual magnetism on the adsorption block to compress the pressure sensor, and then the amount of residual magnetism of the iron core can be indirectly judged by the pressure value signal of the pressure sensor; this design of the embodiment of the present invention effectively avoids the detection errors that may exist in traditional detection schemes, and can significantly improve the accuracy of residual magnetism detection; further explanatory, accurate residual magnetism detection provides a reliable basis for the elimination of residual magnetism of the converter transformer, ensures the safe use of the converter transformer, and can reduce the risk of equipment failure caused by residual magnetism.

[0026] Further specifically explained, in the technical solution of the embodiment of the present invention, the shell is made of non-ferromagnetic material, which avoids the influence of the shell itself on the magnetic field and ensures the accuracy of residual magnetism detection; the flexible pressure sensor is used to better adapt to the small displacement of the adsorption block and improve the sensitivity of detection; the adsorption block of ferromagnetic material has a strong response to residual magnetism, ensuring the effectiveness of detection; the pressure sensor and the adsorption block are both encapsulated in the shell, which protects the sensor from interference from the external environment and improves the stability of detection; the pressure sensor and the adsorption block are encapsulated in the shell, which provides a relatively stable working environment for the pressure sensor. This packaging method effectively isolates the influence of the oil pressure change of the transformer oil on the pressure sensor and avoids the detection error caused by the oil pressure fluctuation; in addition, the flexible pressure sensor adopts the design of dielectric layer and electrode layer, which has extremely high sensitivity to the change of pressure, can better adapt to various complex detection environments, and improves the scope of application of detection. In summary, the technical solution disclosed in the embodiment of the present invention significantly improves the detection accuracy of residual magnetism, provides a strong guarantee for the accurate elimination of residual magnetism, and provides important technical support for the safe use of converter transformers.

[0027] In one embodiment of the present invention, the converter transformer residual magnetism detection sensor disclosed in the embodiment of the present invention is installed in the transformer oil tank, specifically, it is installed on the top or side of the transformer oil tank through a flange, so that the end face of the converter transformer residual magnetism detection sensor is flush with the inner wall of the oil tank, and the pressure sensor 2 is located between the iron core and the adsorption block 3. When there is residual magnetism in the iron core, the adsorption block 3 will be attracted to compress the pressure sensor 2, and different pressure values ​​will be formed according to the residual magnetism. The residual magnetism of the iron core can be calculated based on the pressure value.

[0028] In one embodiment of the present invention, the shell 1 includes a base 11 and a cover 12, the base 11 is a circular plate made of aluminum alloy, the cover 12 is a cylindrical structure with one end open, the cover 12 is made of plastic, and the outer side of the cover 12 is covered with an electric field shielding layer, which can be a copper mesh or an aluminum alloy coating; the cover 12 is glued to the upper end surface of the base 11, thereby forming a accommodating cavity for installing the pressure sensor 2 and the adsorption block 3 between the base 11 and the cover 12. Among them, the pressure sensor 2 is attached to the inner end surface of the cover 12. The pressure sensor 2 includes a dielectric layer 21, an electrode layer 22 and a signal line 23. The dielectric layer 21 is a porous material. The two electrode layers 22 are respectively attached to the two sides of the dielectric layer 21. The two signal lines 23 are respectively electrically connected to the two electrode layers 22. A threading hole 111 is opened at the center of the base 11. The signal line 23 of the pressure sensor 2 extends out of the shell 1 through the threading hole 111, and a sealing material is filled between the signal line 23 and the threading hole 111 to ensure the sealing of the shell 1 and prevent transformer oil from entering the shell 1. The adsorption block 3 is a steel disc, and the adsorption block 3 is attached to the other side of the pressure sensor 2. A guide hole is opened at the center of the adsorption block 3, and a guide column 13 is fixed at the center of the base 11. The adsorption block 3 is sleeved on the guide column 13 through the guide hole to prevent the adsorption block 3 from deviating and affecting the detection of the pressure sensor 2.

[0029] In the preferred technical solution of the embodiment of the present invention, the threading hole opened on the base facilitates the lead-out of the signal line while maintaining the integrity of the shell; the sealing material is filled between the signal line and the threading hole, which effectively prevents transformer oil or other impurities from entering the shell, ensuring the long-term stable operation of the sensor; the guide pillars on the base cooperate with the guide holes on the adsorption block to provide a stable guide for the adsorption block, ensuring the accurate displacement of the adsorption block under the action of the magnetic field; the design of the guide pillars and the guide holes also simplifies the installation process of the sensor and improves the installation efficiency; the electric field shielding layer arranged on the outside of the shell can effectively shield the influence of the external electric field on the sensor, and improves the anti-interference ability of the detection; in addition, the electric field shielding layer also provides an extra layer of protection for the sensor, extending the service life of the sensor.

[0030] In one embodiment of the present invention, the shell 1 is evacuated to form a negative pressure environment, which prevents the air in the holes in the dielectric layer from affecting the compression of the dielectric layer, thereby ensuring the measurement accuracy of the residual magnetism detection sensor. Further explaining, the negative pressure environment in the shell effectively eliminates the influence of the internal air on the action of the adsorption block and the detection accuracy of the pressure sensor; the negative pressure environment also enhances the sealing of the shell and improves the stability of the sensor.

[0031] In a specific embodiment of the present invention, the adsorption block 3 is a plurality of steel sheets, and an array of the adsorption blocks 3 is attached to one side of the pressure sensor 2 .

[0032] In one embodiment of the present invention, a method for preparing a converter transformer residual magnetism detection sensor specifically comprises the following steps: Step S1, preparing a pressure sensor, specifically comprising: Step S11, preparing a dielectric material dispersion, wherein the dielectric material is a mixture of carbon nanotubes and carbon black; wherein the carbon nanotubes and carbon black are weighed, added into an isopropanol solution, magnetically stirred for 20 minutes, and then ultrasonically dispersed for 1.5 hours to obtain a suspension of the carbon nanotubes and carbon black; Step S12, preparing a polydimethylsiloxane dispersion, comprising: weighing polydimethylsiloxane, adding the mixture into an isopropanol solution, and magnetically stirring the mixture for 30 minutes to obtain a polydimethylsiloxane dispersion; Step S13, slowly adding the dielectric material dispersion into the polydimethylsiloxane dispersion, performing magnetic stirring while adding, and continuing stirring for 30 minutes after complete addition to obtain a mixed solution of carbon nanotubes, carbon black and dimethylsiloxane; Step S14, adding fully ground sodium chloride particles to the mixed solution obtained in step S13, heating to 80° C. and stirring until the solvent evaporates to make the mixed solution colloid, adding a curing agent in a ratio of 10:1 and continuing to stir evenly; Step S15, applying the colloid obtained in step S14 on a mold, drying and curing to obtain a thin film; wherein the mold surface is provided with wavy microgrooves; the wavy microgrooves form an arc-shaped convex structure on the surface of the dielectric layer, so that the pressure sensor is easily compressed, thereby greatly improving the sensitivity of the sensor; Step S16, placing the film obtained in step S15 into deionized water, heating it to 70° C. and stirring it continuously to wash away the sodium chloride particles in the film, thereby obtaining a porous film; Step S17, cutting the porous film obtained in step S16 into small particles, attaching conductive glue on both sides as electrode layers, and leading out electrodes through copper wires to obtain a pressure sensor; Step S2, attaching the adsorption block to the pressure sensor; Step S3, assembling the pressure sensor and the adsorption block into the housing so that the pressure sensor is fixed to the inner wall of the housing; Step S4, drilling holes in the shell and sealing the shell.

[0033] In summary, the embodiment of the present invention discloses a converter transformer residual magnetism detection sensor and a preparation method thereof. The converter transformer residual magnetism detection sensor is installed in the transformer oil tank, and includes a shell, a pressure sensor and an adsorption block. The shell is made of non-ferromagnetic material, the pressure sensor is a flexible pressure sensor, the adsorption block is made of ferromagnetic material, the pressure sensor and the adsorption block are both encapsulated in the shell, one end face of the pressure sensor is connected to the inner wall of the shell, and the other end face of the pressure sensor is connected to the adsorption block. The technical solution of the embodiment of the present invention can compress the pressure sensor according to the adsorption of the residual magnetism on the adsorption block, and judge the amount of the residual magnetism of the iron core by detecting the pressure value of the pressure sensor, thereby improving the accuracy of residual magnetism detection, thereby improving the accuracy of residual magnetism elimination of the converter transformer, and improving the safety of the use of the converter transformer.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A converter transformer residual magnetism detection sensor, characterized in that: include: A housing (1), a pressure sensor (2) and an adsorption block (3); The pressure sensor (2) and the adsorption block (3) are both encapsulated in the housing (1); one side of the pressure sensor (2) is connected to the inner wall of the housing (1), and the other side of the pressure sensor (2) is provided with the adsorption block (3); The shell (1) is made of non-ferromagnetic material, and the adsorption block (3) is made of ferromagnetic material; The pressure sensor (2) is a flexible pressure sensor, comprising a dielectric layer (21) and electrode layers (22) respectively arranged on both sides of the dielectric layer (21); The converter transformer residual magnetism detection sensor is used to be installed on a transformer oil tank, the pressure sensor (2) is located between the iron core of the converter transformer and the adsorption block (3), the adsorption block (3) is used to compress the pressure sensor (2) under the action of the residual magnetism in the iron core, and the pressure sensor (2) is used to output a pressure value signal under the compression of the adsorption block (3).

2. A converter transformer residual magnetism detection sensor according to claim 1, characterized in that: The housing (1) comprises a base (11) and a cover (12), wherein the cover (12) is used to be detachably mounted on the base (11); The pressure sensor (2) is provided with a signal line (23), and the signal line (23) is used to output the pressure value signal; The base (11) is provided with a threading hole (111), and a signal line (23) of the pressure sensor (2) extends out of the housing (1) through the threading hole (111), and a sealing material is filled between the signal line (23) and the threading hole (111); A guide column (13) is provided on the base (11), a guide hole is provided on the adsorption block (3), and the adsorption block (3) is sleeved and installed on the guide column (13) through the guide hole.

3. A converter transformer residual magnetism detection sensor according to claim 1, characterized in that: An electric field shielding layer is provided on the outer side of the shell (1).

4. A converter transformer residual magnetism detection sensor according to claim 1, characterized in that: The shell (1) is in a negative pressure environment.

5. A converter transformer residual magnetism detection sensor according to claim 1, characterized in that: The surface of the dielectric layer (21) of the flexible pressure sensor forms an arc-shaped convex structure.

6. A converter transformer residual magnetism detection sensor according to claim 1, characterized in that: Also includes: A calculation terminal is used to obtain a pressure value signal output by the pressure sensor (2), and calculate the amount of residual magnetism in the iron core of the converter transformer based on the pressure value signal.

7. A method for preparing a converter transformer residual magnetism detection sensor according to claim 1, characterized in that: The following steps are involved: Preparing a pressure sensor (2), attaching an adsorption block (3) to the pressure sensor (2), and encapsulating the pressure sensor (2) and the adsorption block (3) in a housing (1); The steps of preparing the pressure sensor (2) include: adding a dielectric material dispersion into a polydimethylsiloxane dispersion to obtain a mixed solution; adding sodium chloride into the mixed solution, heating and stirring until it becomes a colloid, adding a curing agent into the colloid, stirring evenly and applying it to a mold, drying and curing to obtain a film; washing the obtained film in deionized water to remove the sodium chloride to obtain a porous film; and encapsulating the porous film between two electrode layers (22) to obtain the pressure sensor (2).

8. The method for preparing a converter transformer residual magnetism detection sensor according to claim 7, characterized in that: The dielectric material is a mixture of one or both of carbon nanotubes and carbon black.

9. The method for preparing a converter transformer residual magnetism detection sensor according to claim 7, characterized in that: The specific steps of packaging the pressure sensor (2) and the adsorption block (3) into the housing (1) include: Assembling the pressure sensor (2) and the adsorption block (3) into the housing (1), wherein one end surface of the pressure sensor (2) is connected to the inner wall of the housing (1), and the other end surface of the pressure sensor (2) is connected to the adsorption block (3); The shell (1) is subjected to a vacuum hole processing, and after a negative pressure environment is formed in the shell (1), the shell (1) is sealed.

10. The method for preparing a converter transformer residual magnetism detection sensor according to claim 7, characterized in that: The surface of the mould is provided with wavy microgrooves, and the wavy microgrooves are used to form an arc-shaped convex structure on the surface of the dielectric layer (21).

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