Preparation method of paper-fluorocarbon composite insulator

Abstract

The invention discloses a preparation method of paper-fluorocarbon compound composite insulation, which comprises the following steps: cutting insulation paper into small square blocks, and drying the small square blocks in a vacuum drying oven; the method comprises the following steps of: extracting 400-600mL of fluorinated liquid into a heating magnetic stirrer, heating and electromagnetically stirring the fluorinated liquid, vacuumizing the fluorinated liquid by using a vacuumizing pump, and dehydrating and degassing the fluorinated liquid; putting the dried insulation paper and the dehydrated and degassed fluorination liquid into an impregnation tank, and putting the impregnation tank into a vacuum drying box for impregnation to obtain paper-fluorocarbon compound composite insulation; the prepared paper-fluorocarbon compound composite insulation sample is sealed and stored, and air and moisture are prevented from invading. The novel environment-friendly, safe, flash-point-free and non-flammable composite insulating material is obtained, and the safety problems of flammability, explosion and the like existing in oil paper insulation in a high-capacity high-frequency transformer are solved. Composite insulation formed by impregnation of the fluorination liquid and the insulation paper has important significance in application in high-capacity high-frequency transformers.

Description

Technical Field

[0001] The invention relates to the technical field of engineering dielectrics and electrical engineering, and in particular to a method for preparing paper-fluorocarbon compound composite insulation. Background Art

[0002] A high proportion of renewable energy and a high proportion of power electronic equipment are two major characteristics of the new power system. In recent years, the access and flexible control of new energy sources with power electronics as the interface are important requirements for the development of large-capacity AC / DC transmission and distribution projects such as offshore wind power and photovoltaic power generation. With the development needs of large-capacity AC / DC transmission and distribution projects, the capacity of power electronic transformers has reached hundreds of megavolt-amperes, and the efficiency and power density requirements are extremely high. They need to operate at a high frequency of more than 10kHz, which poses an important challenge to the development and application of core equipment high-frequency transformers. Due to the small size, high power density and high field strength of large-capacity high-frequency transformers, they operate under high-frequency non-sinusoidal complex stress; the core and winding losses are large at high frequencies, and the insulation medium loss is also significantly increased, resulting in an increase in the temperature of the high-frequency transformer, and the heating and insulation failure problems caused by its electrical, magnetic, thermal and force multi-physical fields are prominent. Ensuring good insulation performance of high-frequency transformers and synergistically improving their heat dissipation efficiency are key issues in the design of insulation systems for large-capacity high-frequency transformers.

[0003] The main insulation of high-frequency transformers is often encapsulated with solid insulation such as epoxy resin or silicone rubber. Although solid insulation has high dielectric strength and good mechanical properties, it has low thermal conductivity and is difficult to dissipate heat. Traditional transformer liquid insulation, such as transformer oil, or oil-paper composite insulation, has good insulation properties and can also flow heat to achieve the purpose of heat dissipation. However, transformer oil is flammable and explosive, making it difficult to maintain the transformer safely. Therefore, exploring new liquid insulation and composite insulation systems, studying their insulation properties, and proposing methods to synergistically improve high-frequency insulation performance and heat dissipation are of great significance to the development of large-capacity high-frequency transformers.

[0004] Fluorocarbon is a chemical of hydrofluoroether polymer, which is colorless, transparent and has low viscosity. It is used in products of military, industrial, electronic and other industries because of its environmental friendliness, safety, no flash point, non-flammability, high safety and strong performance compatibility. At present, fluorocarbon is mainly used in the field of power products for efficient heat dissipation. Phase change cooling technology is used to dissipate heat of various electronic devices through evaporation and impregnation. Since fluorocarbon has good insulation properties, it is expected to be used in power electronics and high-voltage direct current transmission equipment. Therefore, it is necessary to prepare a new type of paper-fluorocarbon composite insulation. Summary of the invention

[0005] The purpose of the present invention is to provide a paper-fluorocarbon composite insulation and a preparation method for use in large-capacity high-frequency transformers, reduce the insulation medium loss of large-capacity high-frequency transformers under high-frequency non-sinusoidal complex stress, solve the heating and insulation failure problems caused by electrical, magnetic, thermal and force multi-physical fields, improve the insulation electrical strength and electrical life, and be environmentally friendly, safe, flash-free, non-flammable, and extremely safe.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preparing paper-fluorocarbon composite insulation.

[0008] Step 1: Cut the insulating paper into a suitable size (square with a side length of 40mm to 70mm) and place it in a vacuum drying oven for drying;

[0009] Step 2: draw an appropriate amount of fluorinated liquid into a heated magnetic stirrer, heat and electromagnetically stir the fluorinated liquid, and use a vacuum pump to evacuate the fluorinated liquid to dehydrate and degas the fluorinated liquid;

[0010] Step 3: Put the dried insulating paper and the dehydrated and degassed fluorinated liquid into an impregnation tank, and put them into a vacuum drying oven for heating and impregnation to obtain paper-fluorocarbon composite insulation;

[0011] Step 4: Store the prepared paper-fluorocarbon composite insulation sample in a sealed container to prevent air and moisture from entering.

[0012] Preferably, when the insulating paper is dried, the temperature of the vacuum drying oven is 105 to 120° C., the pressure is in a vacuum state of 50 Pa, and the drying time is 36 to 48 hours.

[0013] Preferably, when the fluorinated liquid is subjected to dehydration and degassing treatment, the heating temperature is 80-90° C., the stirring method is electromagnetic stirring, and the stirring time is 36-48 hours.

[0014] Preferably, the mass ratio of the fluorinated liquid to the insulating paper during impregnation is 20:1.

[0015] Preferably, the immersion temperature is set at 50-70°C and the immersion time is 48-60 hours.

[0016] Preferably, the insulating paper is NOMEX 410 cellulose insulating paper produced by DuPont of the United States.

[0017] Preferably, the insulating paper is cut to a thickness of 0.13 mm and a size of 50 mm×50 mm.

[0018] Preferably, the fluorinated liquid is FC-40 fluorinated liquid produced by 3M Company of the United States.

[0019] Beneficial effects of the present invention:

[0020] The present invention prepares a new type of paper-fluorocarbon compound composite insulation to obtain a new type of composite insulation material that is environmentally friendly, safe, has no flash point and is non-flammable, so that the safety problems of flammability and explosion of oil-paper insulation in large-capacity high-frequency transformers are improved. At the same time, the fluorinated liquid has excellent electrical insulation properties, and the composite insulation formed by impregnation with insulating paper is of great significance in the application of large-capacity high-frequency transformers. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in 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 only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0022] Figure 1 It is a flow chart of the preparation technology of the paper-fluorocarbon composite insulation of the present invention;

[0023] Figure 2 The figure is a graph showing the change in volume resistivity of the paper-fluorocarbon insulation sample prepared according to the present invention as a function of applied electric field.

[0024] Figure 3 The figure is a graph showing the change in volume resistivity of the paper-fluorocarbon insulation sample prepared according to the present invention with temperature. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0028] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0029] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0030] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0032] like Figure 1 The present invention provides a preparation technology of paper-fluorocarbon composite insulation, the steps are as follows:

[0033] Step S101: Cut NOMEXT410 insulation paper produced by DuPont of the United States into square samples with a thickness of 0.13 mm and a size of 50 mm×50 mm, and place them in a vacuum drying oven. The vacuum drying oven is set at a temperature of 105°C and a pressure of 50 Pa in a vacuum state, and the insulation paper is dried for 48 hours in this state;

[0034] Step S102: Take an appropriate amount of FC-40 fluorinated liquid produced by 3M Company of the United States and put it into a heated magnetic stirrer, set the temperature to 90°C, perform heating electromagnetic stirring, expel the bubbles in the fluorinated liquid, and use a vacuum pump to vacuumize the device. Dehydrate and degas the fluorinated liquid in this state for 48 hours;

[0035] Step S103: Place the dried insulating paper into an impregnation tank, and inject dehydrated and degassed fluorinated liquid at a mass ratio of 20:1 between the fluorinated liquid and the insulating paper. Place the impregnation tank in a vacuum drying oven and heat it. The vacuum drying oven is set to 60°C. The impregnation time is 48 hours to ensure that the insulating paper and the fluorinated liquid are fully impregnated.

[0036] Step S104: Finally, the prepared paper-fluorocarbon composite insulation sample is sealed and stored to prevent air and moisture from invading.

[0037] Figure 2 and Figure 3 It is the test result of volume resistivity of paper-fluorocarbon composite insulation. Figure 2 It can be seen that the prepared composite insulating sample has a high volume resistivity and has good insulating properties. In addition, as the electric field increases, the volume resistivity decreases, but the change is not large, indicating that the composite insulating sample is suitable for high-field insulation applications. The volume resistivity can represent the resistance characteristics of a material, which is an important characteristic of insulating materials and reflects the ability to hinder electric current. For insulating materials, the higher the volume resistivity, the better the insulating performance of the material. Therefore, the volume resistivity of the paper-fluorocarbon composite insulating material prepared by the present invention is tested, and different external conditions, such as different temperatures and different electric field strengths, are applied to it to measure the volume resistivity. Figure 2 As shown in the figure, the volume resistivity obtained by testing under different electric field strengths can be seen. It can be seen that the volume resistivity of paper-fluorocarbon composite insulation gradually decreases with the increase of applied field strength. When the applied field strength is 5kV / mm, the volume resistivity is as high as 5.26×1014Ω·m. When the applied field strength increases to 10kV / mm and 15kV / mm, the volume resistivity does not decrease rapidly. When the applied field strength reaches 20kV / mm, the volume resistivity decreases rapidly to 2.74Ω·m. Figure 3It can be seen that the prepared composite insulation sample has a high volume resistivity, and as the temperature increases, the volume resistivity decreases. Good insulation performance can be maintained before the temperature is 80°C. It can be seen that the volume resistivity gradually decreases with the increase of temperature. The volume resistivity reaches a maximum of 6.84×1014Ω·m at room temperature of 20°C, and the volume resistivity drops to 0.85×1014Ω·m at a temperature of 100°C. Compared with other insulating materials, the volume resistivity of transformer oil at 20°C is 4.37×1012Ω·m, and the volume resistivity of oil-impregnated paperboard at 20°C is 5.09×1014Ω·m, while the volume resistivity of paper-fluorocarbon prepared by the technology of the present invention at 20°C is significantly higher, reaching 6.84×1014Ω·m. By comparison, it can be concluded that the volume resistivity of the paper-fluorocarbon composite insulation prepared by the technology of the present invention has been greatly improved, and the electrical insulation performance of the obtained paper-fluorocarbon composite insulation is better.

[0038] The preparation method and process of the paper-fluorocarbon composite insulation of the present invention are described in detail below with multiple specific embodiments and comparative examples:

[0039] Embodiment 1:

[0040] The present invention provides a preparation technology of paper-fluorocarbon composite insulation, the steps are as follows:

[0041] Step S101: Cut NOMEXT410 insulation paper produced by DuPont of the United States into square samples with a thickness of 0.13 mm and a size of 50 mm×50 mm, and place them in a vacuum drying oven. The vacuum drying oven is set at a temperature of 120°C and a pressure of 50 Pa in a vacuum state, and the insulation paper is dried for 36 hours in this state;

[0042] Step S102: Take an appropriate amount of FC-40 fluorinated liquid produced by 3M Company of the United States and put it into a heated magnetic stirrer, set the temperature to 80°C, perform heating electromagnetic stirring, expel the bubbles in the fluorinated liquid, and use a vacuum pump to vacuumize the device. Dehydrate and degas the fluorinated liquid in this state for 48 hours;

[0043] Step S103: Place the dried insulating paper into an impregnation tank, and inject dehydrated and degassed fluorinated liquid at a mass ratio of fluorinated liquid to insulating paper of 20:1. Place the impregnation tank in a vacuum drying oven and heat it. The vacuum drying oven is set to 70°C. The impregnation time is 60 hours to ensure that the insulating paper and the fluorinated liquid are fully impregnated.

[0044] Step S104: Finally, the prepared paper-fluorocarbon composite insulation sample is sealed and stored to prevent air and moisture from invading.

[0045] Embodiment 2:

[0046] The present invention provides a preparation technology of paper-fluorocarbon composite insulation, the steps are as follows:

[0047] Step S101: Cut NOMEXT410 insulation paper produced by DuPont of the United States into square samples with a thickness of 0.13 mm and a size of 50 mm×50 mm, and place them in a vacuum drying oven. The vacuum drying oven is set at a temperature of 110°C and a pressure of 50 Pa in a vacuum state, and the insulation paper is dried for 40 hours in this state;

[0048] Step S102: Take an appropriate amount of FC-40 fluorinated liquid produced by 3M Company of the United States and put it into a heated magnetic stirrer, set the temperature to 90°C, perform heating and electromagnetic stirring, discharge the bubbles in the fluorinated liquid, and use a vacuum pump to vacuumize the device. Dehydrate and degas the fluorinated liquid in this state for 36 hours;

[0049] Step S103: Place the dried insulating paper into an impregnation tank, and inject dehydrated and degassed fluorinated liquid at a mass ratio of 20:1 between the fluorinated liquid and the insulating paper. Place the impregnation tank in a vacuum drying oven and heat it. The vacuum drying oven is set to 50°C. The impregnation time is 48 hours to ensure that the insulating paper and the fluorinated liquid are fully impregnated.

[0050] Step S104: Finally, the prepared paper-fluorocarbon composite insulation sample is sealed and stored to prevent air and moisture from invading.

[0051] Embodiment 3:

[0052] The present invention provides a preparation technology of paper-fluorocarbon composite insulation, the steps are as follows:

[0053] Step S101: Cut NOMEXT410 insulation paper produced by DuPont of the United States into square samples with a thickness of 0.13 mm and a size of 50 mm×50 mm, and place them in a vacuum drying oven. The vacuum drying oven is set at a temperature of 115°C and a pressure of 50 Pa in a vacuum state, and the insulation paper is dried for 48 hours in this state;

[0054] Step S102: Take an appropriate amount of FC-40 fluorinated liquid produced by 3M Company of the United States and put it into a heated magnetic stirrer, set the temperature to 85°C, perform heating electromagnetic stirring, expel the bubbles in the fluorinated liquid, and use a vacuum pump to vacuumize the device. Dehydrate and degas the fluorinated liquid in this state for 48 hours;

[0055] Step S103: Place the dried insulating paper into an impregnation tank, and inject dehydrated and degassed fluorinated liquid at a mass ratio of 20:1 between the fluorinated liquid and the insulating paper. Place the impregnation tank in a vacuum drying oven and heat it. The vacuum drying oven is set to 60°C. The impregnation time is 54 hours to ensure that the insulating paper and the fluorinated liquid are fully impregnated.

[0056] Step S104: Finally, the prepared paper-fluorocarbon composite insulation sample is sealed and stored to prevent air and moisture from invading.

[0057] Embodiment 4:

[0058] The present invention provides a preparation technology of paper-fluorocarbon composite insulation, the steps are as follows:

[0059] Step S101: Cut NOMEXT410 insulation paper produced by DuPont of the United States into square samples with a thickness of 0.13 mm and a size of 50 mm×50 mm, and place them in a vacuum drying oven. The vacuum drying oven is set at a temperature of 120°C and a pressure of 50 Pa in a vacuum state, and the insulation paper is dried for 40 hours in this state;

[0060] Step S102: Take an appropriate amount of FC-40 fluorinated liquid produced by 3M Company of the United States and put it into a heated magnetic stirrer, set the temperature to 80°C, perform heating electromagnetic stirring, expel the bubbles in the fluorinated liquid, and use a vacuum pump to vacuumize the device. Dehydrate and degas the fluorinated liquid in this state for 36 hours;

[0061] Step S103: Place the dried insulating paper into an impregnation tank, and inject dehydrated and degassed fluorinated liquid at a mass ratio of 20:1 between the fluorinated liquid and the insulating paper. Place the impregnation tank in a vacuum drying oven and heat it at 70°C. The impregnation time is 48 hours to ensure that the insulating paper and the fluorinated liquid are fully impregnated.

[0062] Step S104: Finally, the prepared paper-fluorocarbon composite insulation sample is sealed and stored to prevent air and moisture from invading.

[0063] Embodiment 5:

[0064] The present invention provides a preparation technology of paper-fluorocarbon composite insulation, the steps are as follows:

[0065] Step S101: Cut NOMEXT410 insulation paper produced by DuPont of the United States into square samples with a thickness of 0.13 mm and a size of 50 mm×50 mm, and place them in a vacuum drying oven. The vacuum drying oven is set at a temperature of 110°C and a pressure of 50 Pa in a vacuum state, and the insulation paper is dried for 48 hours in this state;

[0066] Step S102: Take an appropriate amount of FC-40 fluorinated liquid produced by 3M Company of the United States and put it into a heated magnetic stirrer, set the temperature to 85°C, perform heating electromagnetic stirring, expel the bubbles in the fluorinated liquid, and use a vacuum pump to vacuumize the device. Dehydrate and degas the fluorinated liquid in this state for 36 hours;

[0067] Step S103: Place the dried insulating paper into an impregnation tank, and inject dehydrated and degassed fluorinated liquid at a mass ratio of fluorinated liquid to insulating paper of 20:1. Place the impregnation tank in a vacuum drying oven and heat it. The vacuum drying oven is set to 50°C. The impregnation time is 60 hours to ensure that the insulating paper and the fluorinated liquid are fully impregnated.

[0068] Step S104: Finally, the prepared paper-fluorocarbon composite insulation sample is sealed and stored to prevent air and moisture from invading.

[0069] Although the embodiments of the present invention are described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments and application fields, and the above-mentioned specific embodiments are only illustrative and instructive, rather than restrictive. Under the guidance of the specification, a person skilled in the art can also make many forms without departing from the scope of protection of the claims of the present invention, all of which belong to the scope of protection of the present invention.

Claims

1. A method for preparing paper-fluorocarbon composite insulation, characterized in that: Cut the insulating paper into squares with a side length of 40 mm to 70 mm and place them in a vacuum drying oven for drying; 400 mL to 600 mL of fluorinated liquid is drawn into a heated magnetic stirrer, the fluorinated liquid is heated and electromagnetically stirred, and a vacuum pump is used to evacuate the fluorinated liquid to dehydrate and degas the fluorinated liquid; The dried insulating paper and the dehydrated and degassed fluorinated liquid are placed in an impregnation tank, and then placed in a vacuum drying oven for impregnation to obtain a paper-fluorocarbon composite insulation; The prepared paper-fluorocarbon composite insulation samples were sealed and stored to prevent the intrusion of air and moisture.

2. The method for preparing a paper-fluorocarbon composite insulation according to claim 1, characterized in that: When the insulating paper is dried, the temperature of the vacuum drying oven is 105-120°C, the pressure is 50Pa in a vacuum state, and the drying time is 36-48h.

3. The method for preparing a paper-fluorocarbon composite insulation according to claim 1, characterized in that: When the fluorinated liquid is dehydrated and degassed, the heating temperature is 80-90°C, the stirring method is electromagnetic stirring, and the stirring time is 36-48h.

4. The method for preparing a paper-fluorocarbon composite insulation according to claim 1, characterized in that: The mass ratio of fluorinated liquid to insulating paper during impregnation is 20:

1.

5. The method for preparing a paper-fluorocarbon composite insulation according to claim 1, characterized in that: During the immersion process, the temperature is set at 50-70°C and the time is 48-60 hours.

6. The method for preparing a paper-fluorocarbon composite insulation according to claim 1, characterized in that: The insulation paper is NOMEX 410 cellulose insulation paper produced by DuPont of the United States.

7. The method for preparing a paper-fluorocarbon composite insulation according to claim 1, characterized in that: The insulating paper is cut into a thickness of 0.13 mm.

8. The method for preparing a paper-fluorocarbon composite insulation according to claim 1, characterized in that: The fluorinated liquid used was FC-40 fluorinated liquid produced by 3M Company of the United States.

9. A paper-fluorocarbon composite insulation obtained by the preparation method described in claims 1 to 8.

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