Dry-type transformer and manufacturing method

Abstract

The invention discloses a dry-type transformer and a manufacturing method. The method comprises the steps that in the winding preparation process of the dry-type transformer, a second insulating layer is additionally arranged between a first insulating layer and a first coil of a winding, a guide pipe is arranged between the first insulating layer and the second insulating layer, and the second insulating layer is used for isolating the guide pipe from the first coil; then placing an optical fiber sensor into the conduit; and finally, the iron core and the winding are assembled to obtain the dry-type transformer, the preparation mode is simple and efficient, the cost is low, and the internal temperature of the transformer can be measured through the optical fiber sensor.

Description

Technical Field

[0001] This application relates to the technical field of transformers, and particularly to a dry-type transformer and a manufacturing method thereof. Background Art

[0002] Power transformers are important electrical equipment widely used in the power system. They are important connecting equipment in each link from power generation to transmission and then to supply to users. Their safe operation is a necessary condition for the normal operation of the entire power system. At present, the main transformer protections configured for distribution network dry-type transformers include electrical protections such as differential protection, body protection, backup protection, overcurrent protection, and zero-sequence current protection. However, they are all electrical protections. During the operation of the transformer, a large amount of heat will be generated. If the temperature is too high, it will cause the insulating material to age, deform, or even burn out, affecting the service life of the transformer.

[0003] Therefore, how to measure the internal temperature of the transformer is a hot issue in current research. Summary of the Invention

[0004] This application provides a dry-type transformer and a manufacturing method thereof, which can measure the internal temperature of the transformer.

[0005] In a first aspect, this application provides a manufacturing method of a dry-type transformer, and the method includes:

[0006] During the winding preparation process, a second insulating layer is added between the first insulating layer of the winding and the first coil, and a conduit is placed between the first insulating layer and the second insulating layer. The second insulating layer is used to isolate the conduit from the first coil;

[0007] A fiber optic sensor is placed into the conduit;

[0008] The prepared winding and the iron core are assembled to obtain the dry-type transformer.

[0009] Based on the first aspect, in an embodiment of this application, before adding the first insulating layer between the first insulating layer of the winding and the first coil and placing the conduit between the first insulating layer and the second insulating layer, the method further includes:

[0010] Obtain the number of winding turns;

[0011] Based on the number of winding turns and the preset placement position of the conduit in the winding, determine the first insulating layer and the first coil.

[0012] Based on the first aspect, in an embodiment of this application, the placement position is the middle layer of the winding. The preparation material of the conduit includes glass fiber; the wall thickness of the conduit is 1 mm, the inner diameter is 2 mm, and the height is the same as the height of the winding.

[0013] Based on the first aspect, in an embodiment of the present application, after inserting the catheter between the first insulating layer and the second insulating layer and before inserting the fiber optic sensor into the catheter, the method further includes: detachably blocking the catheter.

[0014] Based on the first aspect, in an embodiment of the present application, after the winding is completed, the method further includes:

[0015] pre-baking the winding;

[0016] injecting casting material into the winding and heating the winding.

[0017] Based on the first aspect, in an embodiment of the present application, before inserting the fiber optic sensor into the catheter, the method further includes:

[0018] grinding the cooled winding;

[0019] removing the blockage of the catheter.

[0020] Based on the first aspect, in an embodiment of the present application, after inserting the fiber optic sensor into the catheter, the method further includes: injecting insulating material into the catheter.

[0021] Based on the first aspect, in an embodiment of the present application, the coil is a single-layer copper foil, and the insulating layer is epoxy resin or composite foil.

[0022] In a second aspect, the present application provides a dry-type transformer, including a winding, a catheter is disposed in the winding, the catheter is located between a first insulating layer of the winding and a newly added second insulating layer, the second insulating layer is located between the first insulating layer of the winding and a first coil, and the second insulating layer is used to isolate the catheter from the first coil, wherein the first insulating layer and the first coil are determined based on the number of winding turns and the preset insertion position of the catheter in the winding.

[0023] Implementing the present application has the following beneficial effects:

[0024] During the preparation process of the winding of the dry-type transformer, a second insulating layer is added between the first insulating layer of the winding and the first coil, and the catheter is inserted between the first insulating layer and the second insulating layer. The second insulating layer is used to isolate the catheter from the first coil; then the fiber optic sensor is inserted into the catheter; finally, the iron core and the winding are assembled to obtain a dry-type transformer, which not only has a simple and efficient preparation method, low cost, but also can measure the internal temperature of the transformer through the fiber optic sensor. Description of the Drawings

[0025] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0026] Figure 1 It is a schematic flow chart of a manufacturing method of a dry-type transformer provided by an embodiment of the present application;

[0027] Figure 2 It is a schematic plan view of a winding structure provided by an embodiment of the present application;

[0028] Figure 3 It is another schematic plan view of a winding structure provided by an embodiment of the present application;

[0029] Figure 4 It is a schematic flow chart of another manufacturing method of a dry-type transformer provided by an embodiment of the present application;

[0030] Figure 5 It is a schematic diagram of a winding hierarchical structure provided by an embodiment of the present application;

[0031] Figure 6 It is a schematic three-dimensional view of a winding structure provided by an embodiment of the present application. Detailed implementation manners

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0033] The terms "first", "second", "third", "fourth", etc. in the specification, claims and drawings of the present application are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally further include steps or units not listed, or may optionally further include other steps or units inherent to these processes, methods, products or devices.

[0034] References to "embodiments" in this document mean that the specific features, results, or characteristics described in connection with the embodiments may be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment each time, nor are they independent or alternative embodiments mutually exclusive of other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein may be combined with other embodiments.

[0035] First, the relevant terms involved in the present application are explained as follows:

[0036] 1. Dry-type transformer: The dry-type transformer in the embodiments of the present application mainly consists of the following core parts, which work together to achieve the functions of the transformer:

[0037] (1) Iron core: The iron core is the core of the magnetic circuit of the transformer and is usually made of silicon steel sheets with a thickness between 0.35 and 0.5 mm to reduce eddy current losses and iron losses; the structural forms of the iron core are mainly core type and shell type, and the core type structure is more common, which is convenient for the continuity of the magnetic circuit and the arrangement of windings. The present application does not make specific limitations on the iron core.

[0038] (2) Windings: The windings are the circuit part of the transformer and are usually wound with copper or aluminum wires, with an insulating material coated on the outer layer; the windings are divided into high-voltage windings and low-voltage windings. In a dry-type transformer, in order to ensure good electrical isolation and reduce magnetic leakage, the high-voltage winding is usually placed in the part closest to the transformer iron core. This design helps the electric and magnetic fields of the high-voltage winding to better couple with the iron core, thereby improving the working efficiency of the transformer. The low-voltage winding is usually located on the outside and is placed outside the high-voltage winding. This design helps to achieve good heat dissipation because the voltage on the low-voltage side is lower and the voltage stress borne by the winding is smaller. The heat dissipation conditions of the low-voltage winding are better, and it is also easier to connect to an external cooling system (such as a fan, etc.).

[0039] (3) Insulating materials: Common insulating materials include epoxy resin, polyester resin, etc., and the present application does not make limitations.

[0040] (4) Accessories: Dry-type transformers can be equipped with various accessories according to actual needs, such as voltage regulating devices, protection devices (moisture absorber, safety airway, gas relay, etc.), outgoing line bushings, etc. These accessories enhance the functionality and safety of the transformer.

[0041] (5) Shell: According to different usage environments, the shell forms of dry-type transformers are also different. For example, the body of the open type is directly exposed to the air and is suitable for dry and clean indoor environments; the body of the enclosed type is enclosed in the shell and is mainly used in special environments such as mines and belongs to an explosion-proof transformer; Casting type: Epoxy resin or other resins are used for casting as the main insulation, with a simple structure and a compact volume, and is suitable for small-capacity transformers.

[0042] (6) Other components: 1) Fasteners and insulators: such as clamp parts, screws, glass lashing tapes, etc., used to fix and insulate the iron core and windings; 2) Impregnating materials: such as cresol varnish, used to enhance the mechanical strength and insulation performance of the transformer.

[0043] In the embodiments of the present application, for example, the winding can be wound with a single-layer copper foil, that is, the material of the coil can be a single-layer copper foil. The material of the interlayer of the winding, that is, the material of the insulating layer, can be an epoxy resin with a latent curing agent or an insulating material such as a composite foil, or it can include an epoxy resin with a latent curing agent and an insulating material such as a lower composite foil. The present application does not make specific limitations.

[0044] The embodiments of the present application will be explained below with reference to specific drawings, as follows:

[0045] Refer to Figure 1 , Figure 1 which is a schematic flow chart of a manufacturing method of a dry-type transformer provided by the embodiments of the present application. The method includes but is not limited to steps S101 - S103:

[0046] S101. During the preparation of the winding, a second insulating layer is added between the first insulating layer and the first coil of the winding, and a conduit is placed between the first insulating layer and the second insulating layer. The second insulating layer is used to isolate the conduit from the first coil.

[0047] In the embodiments of the present application, before starting the winding, the number of winding turns can be obtained. Among them, the number of winding turns is calculated according to the transformer design parameters and specific models. For example:

[0048] The transformer design parameters mainly include the rated voltage V1 (unit: volt) of the high-voltage side, the rated voltage V2 (unit: volt) of the low-voltage side, the operating frequency f (unit: hertz) of the transformer, the magnetic flux density B (unit: tesla), and the effective cross-sectional area of the iron core (unit: square meter). Then, according to the principles of electromagnetism, the number of turns N1 of the high-voltage side winding is calculated as N1 = V1 / (f * B * A), and similarly, the number of turns N2 of the low-voltage side winding is N2 = V2 / (f * B * A); and since the ratio of the low-voltage side voltage to the high-voltage side voltage determines the turn ratio of the winding, then N1 / N2 = V1 / V2, so N2 = N1 * (V2 / V1). Furthermore, based on the obtained number of turns of the high-voltage side winding and the number of turns of the low-voltage side winding, the number of winding turns is obtained.

[0049] Then the winding preparation can be started. For example, from the inside to the outside, the first layer of the winding is an insulating layer, and then the wound single-layer copper foil is isolated through the insulating layer until the number of turns of the wound single-layer copper foil reaches the above-mentioned number of winding turns, and the last layer of the winding is made of an insulating layer.

[0050] Among them, during the winding process, the first insulating layer and the first coil can be determined based on the number of winding turns and the preset insertion position of the conduit in the winding. For example, the preset insertion position is the middle layer of the winding, which is not limited in this application. Taking the middle layer as an example, for instance:

[0051] Assume that the number of winding turns is i (i.e., the number of coils or the number of single-layer copper foils is i). Correspondingly, in principle, the number of initial insulating layers is i + 1. Then the first coil can be determined based on i / 2. For example, if i is even, the first coil can be the i / 2-th coil or the (i / 2 + 1)-th coil among the i coils; if i is odd, the first coil can be the (i / 2 + 0.5)-th coil among the i coils.

[0052] Furthermore, if i is even and the first coil is the i / 2-th coil or the (i / 2 + 1)-th coil among the i coils, then the first insulating layer is determined to be the ((i + 1) / 2)-th insulating layer among the i + 1 insulating layers. If i is odd and the first coil is the (i / 2 + 0.5)-th coil among the i coils, then the first insulating layer is determined to be the ((i + 1) / 2)-th insulating layer or the ((i + 1) / 2 + 1)-th insulating layer among the i + 1 insulating layers.

[0053] Then, during the winding preparation process, after determining the first insulating layer and the first coil, a second insulating layer can be added between the first insulating layer and the first coil of the winding. Taking the above example, at this time, the number of insulating layers in the winding is updated from i + 1 to i + 2; then the conduit is placed between the first insulating layer and the second insulating layer, and at this time, the second insulating layer is used to isolate the conduit and the first coil. The number of conduits can be one or more, which can be adjusted according to the technical parameters of the dry-type transformer and is not limited in this application; and supports and fillers can also be added in the implantation layer (i.e., between the first insulating layer and the second insulating layer) to prevent problems such as loose structure and excessive winding air gap caused by too small implantation density or number of conduits.

[0054] In addition, the preparation material of the conduit mainly includes glass fiber. The wall thickness of the conduit is 1 mm, the inner diameter is 2 mm, and the height is the same as the height of the winding, which can meet the placement of the fiber optic sensor. In addition, using glass fiber as the preparation material has strong thermal conductivity. While improving the accuracy of temperature measurement by the fiber optic sensor, it is also high-temperature resistant and will not cause loss of the fiber optic sensor due to high temperature.

[0055] For ease of understanding, the winding will be explained below with reference to specific diagrams. Refer to Figure 2 , Figure 2 which is a schematic plan view of a winding provided by an embodiment of this application.

[0056] Taking the preset insertion position as the middle layer of the winding as an example, as Figure 2 The winding shown includes a total of 5 layers. Among them, the number of coils is 2 (i.e., i = 2, corresponding to 2 and 4 in Figure 2 respectively), and the number of insulating layers is 3 (i.e., i + 1 = 3, corresponding to 1, 3, and 5 in Figure 2 respectively); then based on the above principle, since i is an even number, it can be determined that the first coil can be 2 or 4 in Figure 2 respectively, and the first insulating layer is 3 in Figure 2 respectively. Therefore, a second insulating layer can be added between 2 and 3 in Figure 2 respectively, or a second insulating layer can be added between 3 and 4.

[0057] Refer to Figure 3 , Figure 3 which is a schematic plan view of another winding provided by an embodiment of the present application.

[0058] Still taking the pre-set placement position as the middle layer of the winding as an example, as in Figure 3 the winding shown includes a total of 7 layers. Among them, the number of coils is 3 (i.e., i = 3, corresponding to 2, 4, and 6 in Figure 3 respectively), and the number of insulating layers is 4 (i.e., i + 1 = 4, corresponding to 1, 3, 5, and 7 in Figure 3 respectively); then based on the above principle, since i is an odd number, it can be determined that the first coil can be 4 in Figure 3 respectively, and it can be determined that the first insulating layer is 3 or 5 in Figure 3 respectively. Therefore, a second insulating layer can be added between 3 and 4 in Figure 3 respectively, or a second insulating layer can be added between 4 and 5.

[0059] Furthermore, after the conduit is placed into the winding, the conduit is detachably blocked, for example, using insulating tape, which is not limited in the present application; then after cleaning the dirt and dust on the surface of the coils of the winding, pre-baking is performed to evaporate the surface moisture and internal moisture, so as to avoid generating bubbles and cracks during the pouring process.

[0060] Then the casting material corresponding to the dry-type transformer model is slowly injected into the winding to avoid the generation of impact and bubbles, and then the winding is heated using a baking device to ensure that the casting material is completely cured. Among them, the addition time needs to be adjusted according to specific circumstances, while ensuring that the casting material can be completely cured, and avoiding damage to the coils caused by over-baking.

[0061] Then the winding after pouring is subjected to a cooling and curing process to make the casting material fully hardened, improving the mechanical strength and heat resistance of the coils; then the cooled winding is polished to smooth the surface and improve the appearance quality of the winding.

[0062] That is to say, after the winding is made, it needs to be baked. By controlling the temperature and time, the insulating material in the winding is gradually dried to remove the moisture and solvent on its surface or inside. For example, the temperature of the baking process is usually low, controlled between 60℃ and 120℃, depending on the type of insulating material; the time needs to be adjusted according to the type of insulating material, the size of the winding and the capacity of the baking equipment. Usually each baking will take several hours to ensure that all moisture inside the winding is removed. After baking, the winding needs to be slowly cooled at room temperature to avoid thermal stress on the winding due to drastic temperature changes and ensure that its structure is not damaged.

[0063] Then before pouring, the winding is usually placed in a vacuum tank for treatment. This process is called vacuum degassing to remove bubbles and air in the winding, ensuring that the casting material can fully penetrate into every detail and gap of the winding to avoid any bubbles or gaps affecting the insulation performance. After the vacuum treatment is completed, the liquid casting material (usually epoxy resin polyurethane resin or other insulating materials, which have good insulation, heat resistance and mechanical strength after curing; and the material is usually liquid, and needs to be properly mixed and processed before use) is slowly and evenly injected into the winding. The pouring process requires special attention to ensure that each layer of insulation material is evenly covered to avoid local leakage, so as to further enhance the insulation strength and mechanical strength of the winding. After the casting material is poured, the winding needs to be cured under specific temperature conditions. The curing temperature is usually high, such as between 80℃ and 150℃. The curing process usually takes several hours to more than ten hours, depending on the type and thickness of the casting material used, so that the liquid casting material is transformed into a solid solid state to form a hard insulation layer and provide high-strength electrical isolation. After solidification, the winding needs to be cooled in a controlled environment, usually by natural cooling or air cooling, so that the mechanical properties and insulation properties of the casting material can meet the expected requirements.

[0064] S102, placing the optical fiber sensor into the catheter.

[0065] Furthermore, the sealing tape of the catheter is removed, and then the optical fiber sensor is placed in the catheter. Optionally, after the optical fiber sensor is placed in the catheter, an insulating material may be injected into the catheter. The insulating material needs to be resistant to high temperatures, such as epoxy resin, which can fix the optical fiber sensor and isolate the air.

[0066] S103, assembling the prepared winding and iron core to obtain the dry-type transformer.

[0067] After the optical fiber sensor is placed in the catheter, a prepared winding is obtained, and then the iron core can be assembled as the center of the winding; then the assembly is performed according to the assembly steps of the dry-type transformer to obtain the dry-type transformer.

[0068] In an alternative embodiment, after the catheter is inserted into the winding through step S101 and the winding and the iron core are assembled through step S103, the fiber optic sensor can be inserted into the catheter to obtain a dry-type transformer, that is, after the assembly is completed, the fiber optic sensors are uniformly extended through the catheter to one side of the transformer, so that the joints of the fiber optic sensors are uniformly fixed to avoid damage to the fiber optic sensors during the assembly process. That is to say, at this time, the order of execution between step S102 and step S103 can be to execute step S102 first and then step S103, or it can also be to execute step S103 first and then step S102, which is not limited in this application.

[0069] That is to say, in the embodiment of this application, the dry-type transformer includes a winding, a catheter is inserted into the winding, and a fiber optic sensor is inserted into the catheter for measuring the internal temperature of the transformer. The catheter is located between the first insulating layer of the winding and the newly added second insulating layer, and the second insulating layer is located between the first insulating layer of the winding and the first coil. The second insulating layer is used to isolate the catheter from the first coil, where the first insulating layer and the first coil are determined based on the preset insertion position of the winding and the catheter in the winding, and the specific principle will not be elaborated here.

[0070] It should be noted that the fiber optic sensor in the embodiment of this application can be a fiber optic linear temperature sensor, and thus the internal temperature of the dry-type transformer can be monitored through the linear temperature sensor. Next, a temperature monitoring system for a dry-type transformer will be introduced. Specifically:

[0071] The system includes a dry-type transformer, a detection device, and a terminal device. Among them, the detection device includes a light source module, a light receiving module, and a data processing module. First, the light source module (usually a laser) emits laser pulses through the fiber optic sensor inside the dry-type transformer, so that the laser undergoes a scattering effect with the temperature change inside the dry-type transformer to form an optical signal related to the temperature change. For example, the light scatters with molecules, atoms, etc. in the optical fiber during propagation, generating Rayleigh scattering and Raman scattering; and different types of scattering are related to the temperature change around the optical fiber. Rayleigh scattering is mainly affected by the change in the molecular density in the optical fiber transmission path, and Raman scattering is affected by temperature. The higher the temperature, the more the intensity and frequency shift of Raman scattering will change. Then the light receiving module receives the scattered optical signal returned from the fiber optic sensor and converts the optical signal into an electrical signal.

[0072] Then the data processing module processes, analyzes and stores the received electrical signal. Since Raman scattering will cause the optical frequency to shift, and the temperature change will cause the amplitude of the frequency shift to change, the data processing module needs to extract the frequency shift information of Raman scattering from the received electrical signal, such as by performing spectral analysis on the received electrical signal through algorithms such as Fast Fourier Transform (FFT) to determine the frequency shift information corresponding to the electrical signal; then, according to the corresponding relationship between the preset temperature and the frequency shift, determine the temperature corresponding to the frequency shift information, that is, obtain the internal temperature of the dry-type transformer.

[0073] The data processing module can then send the obtained temperature data to the terminal device. Accordingly, the terminal device can display the internal temperature of the dry-type transformer, which is convenient for relevant personnel to view and monitor. When the temperature is abnormal, such as the preset safety threshold, the alarm mode is triggered to remind relevant personnel to take corresponding measures.

[0074] In an optional embodiment, the optical fiber sensor can also be a fiber Bragg Grating sensor (FBG), and its packaging method can be substrate type, tube type and polymer packaging method, so that the fiber Bragg Grating sensor can have strong mechanical strength and long life. When measuring temperature, the signal is first transmitted to the fiber Bragg Grating sensor through the light source module. When the light passes through the optical fiber, the periodically changing refractive index of the optical fiber causes the light of a specific wavelength to be reflected. This reflected wavelength is called the Bragg wavelength. The Bragg wavelength changes with temperature. For example, for every 1°C increase, the Bragg wavelength will have a specific change (such as 0.01nm / °C); then the wavelength of the reflected light can be received from the fiber Bragg Grating sensor through an optical receiving module (such as a spectrometer or a fiber Bragg Grating sensor reader); then the temperature corresponding to the wavelength of the reflected light is determined through the correspondence between the preset temperature and the wavelength, that is, the internal temperature of the dry-type transformer is obtained.

[0075] It should be explained that the temperature sensor based on fiber grating technology adopts wavelength coding technology to eliminate the influence of light source power fluctuation and system loss, and is suitable for long-term monitoring; and the fiber grating sensor is resistant to high temperature and can work in high temperature environment, which is suitable for high voltage and high temperature equipment such as transformers; and the optical fiber itself is resistant to electromagnetic interference and is insensitive to electromagnetic interference, which is suitable for electrical equipment; and the fiber grating sensor has high precision and high sensitivity, can detect tiny temperature changes, and can accurately measure the temperature inside the transformer, thereby improving the operating safety and efficiency of the transformer.

[0076] For further understanding, see Figure 4 , Figure 4Schematic flowchart of another manufacturing method of the dry-type transformer according to the embodiment of the present application. As Figure 4 shown, the method includes:

[0077] (1) Catheter implantation: First, prepare a catheter. The catheter is made of fiberglass, with a wall thickness of 1 mm, an inner diameter of 2 mm, and the same height as the winding. Then, wind the winding and implant the catheter during the winding process. Then, detachably block the catheter. Then, bake and cast the winding.

[0078] (2) Fiber optic sensor implantation: Cool and solidify the winding. Then, grind the winding. Then, remove the catheter blockage. Then, implant the fiber optic sensor into the catheter.

[0079] (3) Transformer assembly: Assemble the iron core and the winding.

[0080] It should be noted that Figure 4 the principles of the steps shown can be correspondingly referred to the Figure 1 explanation of the embodiment, which will not be elaborated here.

[0081] Refer to Figure 5 , Figure 5 which is a schematic diagram of a winding hierarchical structure provided by the embodiment of the present application.

[0082] Taking one catheter and one fiber optic sensor, and the winding coil is wound with a single-layer copper foil and the insulating layer is made of epoxy resin as an example. As Figure 5 shown, during the winding process, the first layer and the last layer of the winding are both insulating layers, i.e., epoxy resin. The single-layer copper foil is isolated by the insulating layer epoxy resin. The catheter is located between the two insulating layers (i.e., corresponding to the first insulating layer and the second insulating layer, both taking epoxy resin as an example), ensuring the insulation performance of the transformer. The fiber optic sensor is placed in the catheter.

[0083] Refer to Figure 6 , Figure 6 which is a schematic three-dimensional structure diagram of a winding provided by the embodiment of the present application. As Figure 6 shown, the innermost layer (i.e., the first layer) and the outermost layer (i.e., the last layer) of the winding are both insulating layers. Then, the catheter is placed at the preset placement position of the winding (i.e., Figure 6 the position where the multiple long-shaped catheters are located in the example), specifically between the first insulating layer and the second insulating layer of the winding. Among them, the first insulating layer and the second insulating layer are between the innermost insulating layer and the outermost insulating layer, Figure 6 and the specific positions of the first insulating layer and the second insulating layer are not shown; then, the catheter is blocked by a detachable blockage such as adhesive tape.

[0084] It can be seen that during the preparation process of the winding of the dry-type transformer, a second insulating layer is added between the first insulating layer and the first coil of the winding, and a conduit is placed between the first insulating layer and the second insulating layer, and the second insulating layer is used to isolate the conduit from the first coil; then an optical fiber sensor is placed into the conduit; finally, the iron core and the winding are assembled to obtain a dry-type transformer. This not only has a simple and efficient preparation method and low cost, but also can measure the internal temperature of the transformer through the optical fiber sensor.

[0085] It should be noted that for the foregoing method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that this application is not limited by the described action sequence, because according to this application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily essential to this application.

[0086] In the above embodiments, the descriptions of the respective embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0087] The embodiments of the present application have been introduced in detail above. Specific examples are used herein to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A method for manufacturing a dry-type transformer, characterized in that: The method comprises: In the process of preparing the winding, a second insulating layer is added between the first insulating layer and the first coil of the winding, and a conduit is placed between the first insulating layer and the second insulating layer, wherein the second insulating layer is used to isolate the conduit from the first coil; placing a fiber optic sensor into the catheter; The prepared winding and iron core are assembled to obtain the dry-type transformer.

2. The method according to claim 1, characterized in that Before adding a first insulating layer between the first insulating layer of the winding and the first coil and placing the conduit between the first insulating layer and the second insulating layer, the method further comprises: Get the number of winding turns; The first insulating layer and the first coil are determined based on the number of turns of the winding and the preset insertion position of the conduit in the winding.

3. The method according to claim 2, characterized in that The placement position is a middle layer of the winding.

4. The method according to any one of claims 1 to 3, characterized in that: The conduit is made of glass fiber; the conduit has a wall thickness of 1 mm, an inner diameter of 2 mm, and a height that is the same as that of the winding.

5. The method according to any one of claims 1 to 4, characterized in that: After placing the catheter between the first insulating layer and the second insulating layer and before placing the optical fiber sensor in the catheter, the method further includes: The conduit is detachably blocked.

6. The method according to claim 5, characterized in that After the winding is completed, the method further includes: Pre-bake the windings; The casting material is poured into the interior of the winding and the winding is heated.

7. The method according to claim 6, characterized in that Before placing the optical fiber sensor into the catheter, the method further comprises: Grind the cooled winding; The occlusion of the conduit is removed.

8. The method according to claim 7, characterized in that After placing the optical fiber sensor into the catheter, the method further comprises: Insulating material is injected into the conduit.

9. The method according to any one of claims 1 to 8, characterized in that: The coil is a single layer of copper foil, and the insulation layer is epoxy resin or composite foil.

10. A dry-type transformer, comprising a winding, characterized in that: The winding is inserted with a catheter, in which an optical fiber sensor is inserted, the catheter is located between the first insulating layer of the winding and a newly added second insulating layer, the second insulating layer is located between the first insulating layer and the first coil of the winding, and the second insulating layer is used to isolate the catheter from the first coil, wherein the first insulating layer and the first coil are determined based on the number of winding turns and the preset insertion position of the catheter in the winding.

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