High-precision core for wind power water-cooled transformer and preparation method thereof

Abstract

The present application relates to transformer anticorrosion technical field, specifically to high-precision iron core for wind power water-cooled transformer and its preparation method. In the present application, the p-methacrylic acid epoxy resin is modified in turn; the p-methacrylic acid epoxy propyl ester is grafted and modified; the filler is compounded and modified; finally, the protective coating is prepared by combining other components. The protective coating comprises the following components by weight fraction: 35-50 parts of modified epoxy resin, 10-15 parts of p-methacrylic acid epoxy propyl ester copolymer, 10-20 parts of modified filler, 50 parts of phosphate, 0.5-5 parts of tungstate, 30-40 parts of ethyl acetate, 2-6 parts of auxiliary agent, 10-20 parts of curing agent, wherein the tungstate addition amount is 1-10% of the mass of phosphate. The protective coating is coated on the iron core for wind power water-cooled transformer, so that the transformer iron core can adapt to more severe working environment and maintain high precision level for a long time.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of transformer anticorrosion, in particular to a high-precision iron core for a wind power water-cooled transformer and a preparation method thereof. BACKGROUND

[0002] In a power system, a transformer is used for voltage conversion of commercial power or industrial power to adapt to different voltage requirements of different equipment, so the transformer needs to have multiple voltage outputs when used for multiple power equipment. In recent years, China's wind power has developed on a large scale, and the demand for wind power water-cooled transformers has increased. However, due to the scattered distribution of wind power stations in remote areas, in order to reduce the maintenance cost in the later period, the transformer needs to have the performance of low failure rate. The transformer iron core is an indispensable important component in the power system, which bears the task of power transmission and conversion, and the quality of the iron core will directly affect the efficiency and reliability of the power system.

[0003] In addition, the application environment of the wind power water-cooled transformer is increasingly complex, and the transformer iron core in the offshore or coastal area is more prone to corrosion, which increases the iron loss of the transformer iron core and significantly reduces the precision, which greatly affects the efficiency of the power system. In order to reduce the iron loss of the transformer iron core, a layer of insulating paint or insulating oxide is generally coated on the surface of the iron core, so that the iron core has a protective layer with moisture resistance, corrosion resistance and certain mechanical strength on the surface, thereby maintaining the high precision of the transformer iron core.

[0004] In summary, the iron core for the wind power water-cooled transformer is protected to enable the transformer to adapt to a more severe working environment, achieve the effect of protecting the quality of the transformer iron core, and enable the transformer iron core to maintain a high precision level for a long time and actively play a role in the power system. SUMMARY

[0005] The purpose of the present application is to provide a high-precision iron core for a wind power water-cooled transformer and a preparation method thereof to solve the problems raised in the background.

[0006] In order to solve the above technical problems, the present application provides the following technical scheme:

[0007] The preparation method of the high-precision iron core for the wind power water-cooled transformer comprises the following steps:

[0008] Step 1: clean the iron core for the wind power water-cooled transformer and dry it for standby use;

[0009] Step 2: coat the protective coating on the iron core for the wind power water-cooled transformer, and obtain the high-precision iron core for the wind power water-cooled transformer after drying and curing.

[0010] Further, the protective coating comprises the following components by weight fraction: 35-50 parts of modified epoxy resin, 10-15 parts of epoxy propyl methacrylate copolymer, 10-20 parts of modified filler, 50 parts of phosphate, 0.5-5 parts of tungstate, 30-40 parts of ethyl acetate, 2-6 parts of auxiliary agent, 10-20 parts of curing agent, wherein the amount of tungstate added is 1-10% of the mass of phosphate.

[0011] Further, the preparation method of the modified epoxy resin is as follows: the following components by weight fraction are mixed in a reaction container: 50 parts of bisphenol A type epoxy resin, 0.01-0.03 parts of hydroquinone, 10-15 parts of methacrylic acid, and 1-2 parts of N,N'-dimethylaniline are added dropwise to the container at 50-80°C, and the reaction is continued for 3-5 hours to obtain the modified epoxy resin.

[0012] In the scheme, the epoxy resin is modified and grafted with methacrylic acid to obtain a modified epoxy resin; due to the grafting of methacrylic acid, the modified epoxy resin has good compatibility with components such as fillers, so that the bonding strength after curing is high, the mechanical properties of the coating can be improved, and excellent weather resistance can be exhibited, thereby providing a longer protection effect.

[0013] Further, the preparation method of the epoxy propyl methacrylate copolymer is as follows: the following components by weight fraction are mixed in a reaction container: (1) under nitrogen protection, 3-5 parts of dodecafluoroheptyl methacrylate, 10-15 parts of epoxy propyl methacrylate, 0.03-0.05 parts of ethyl 2-bromoisobutyrate, 0.01-0.02 parts of copper chloride, 0.08-0.12 parts of tris(2-dimethylaminoethyl)amine, 0.10-0.12 parts of azobisisobutyronitrile, and 6-10 parts of ethyl acetate are sequentially added and mixed, stirred at 60-80°C for 6-12 hours, and subjected to reduced pressure distillation to obtain product A; (2) under nitrogen protection, 0.01-0.02 parts of 4-methoxyphenol and 3-6 parts of piperazine are added and mixed in a reaction container, the temperature is adjusted to 50-85°C, 10-18 parts of product A is added dropwise to the container with stirring, the reaction is continued for 2-3 hours after the addition is completed, 5-10 parts of methyl methanesulfonate is added dropwise to the container, and stirred for 2-3 hours, and finally subjected to reduced pressure distillation to obtain the epoxy propyl methacrylate copolymer.

[0014] In the scheme, first, glycidyl methacrylate and dodecafluoroheptyl methacrylate are grafted to obtain a fluorine-containing block glycidyl methacrylate copolymer, then the fluorine-containing block glycidyl methacrylate copolymer is grafted onto piperazine (forming a tertiary amine) through ring-opening reaction of the epoxy group with a secondary amine, and finally the tertiary amine reacts with methyl methanesulfonate (sulfonic acid group) to form a quaternary ammonium salt type glycidyl methacrylate copolymer. The copolymer has good compatibility with the modified epoxy resin, can improve the adhesion to the substrate, and due to the presence of the quaternary ammonium salt, can provide antistatic effect to the coating; and the fluorine-containing chain end in the copolymer can migrate to the surface of the coating during curing, promote the exertion of the antistatic effect, and protect the transformer core from damage caused by static electricity accumulation.

[0015] Further, the preparation method of the modified filler is as follows: the proportions of the following components are by weight: (1) 10-20 parts of filler is added to 50-100 parts of 10 wt% vinyl silane coupling agent in anhydrous ethanol solution, and after ultrasonic dispersion treatment at 40-60℃ for 1-2h, filtration, washing and drying, a vinyl modified filler is obtained; (2) 10 parts of the vinyl modified filler, 10-20 parts of maleic anhydride and 50 parts of anhydrous ethanol are mixed uniformly to obtain a reaction liquid C; (3) 1 / 2 volume of the reaction liquid C is added to a reaction vessel, 0.1-0.3 parts of dibenzoyl peroxide is added, and after stirring and refluxing at 100-120℃ for 20-40min, the remaining 1 / 2 volume of the reaction liquid C is slowly added dropwise to the reaction system, and after the dropwise addition is completed, the reaction is continued for 2-4h, the reaction is stopped, the reaction system is naturally cooled to room temperature, and after vacuum distillation, washing and drying, a modified filler is obtained.

[0016] Further, the filler is a mixture of nanosilica and activated boron nitride in a mass ratio of 1:(1-3).

[0017] Further, the vinyl silane coupling agent includes but is not limited to any one of vinyltriethoxysilane, vinyltrimethoxysilane and vinyltris(2-methoxyethoxy)silane.

[0018] Further, the activation method of the activated boron nitride is as follows: the proportions of the following components are by weight: 10 parts of nanometer boron nitride and 40-100 parts of 25 wt% sodium hydroxide solution are added to a ball mill, and ball milling treatment is carried out at a speed of 200-500 rpm for 24-48h, and after filtration, washing and drying, an activated boron nitride is obtained.

[0019] In the scheme, the boron nitride is modified by sodium hydroxide activation, so that the surface contains abundant hydroxyl groups, then mixed with nano-silica, and modified by vinyl silane coupling agent, so that the surface is modified by vinyl, and then polymerized by alkene, so that maleic anhydride is polymerized in situ on the surface of the filler, and the modified filler is obtained, wherein the boron nitride can improve the insulation performance of the coating, and the silica can improve the moisture resistance, strength, corrosion resistance and wear resistance of the coating; after modification, the compatibility and interface bonding of the filler and the resin are enhanced, the aggregation and sedimentation of the filler are avoided, the dispersion is uniform, the adhesion between the coating and the substrate is improved, and the performance of the coating can be significantly improved.

[0020] Further, the phosphate salt includes, but is not limited to, a combination of one or more of aluminum dihydrogen phosphate, zinc dihydrogen phosphate, calcium dihydrogen phosphate, nickel dihydrogen phosphate, and magnesium dihydrogen phosphate.

[0021] Further, the phosphate salt is a combination of aluminum dihydrogen phosphate and zinc dihydrogen phosphate, and the mass ratio of aluminum dihydrogen phosphate to zinc dihydrogen phosphate is (3-5):1.

[0022] Further, the tungstate salt includes, but is not limited to, a combination of one or more of sodium tungstate, potassium tungstate, and ammonium tungstate.

[0023] The phosphate salt can form an insulating protective film on the transformer core, and has the characteristics of strong adhesion; in the scheme, the phosphate salt and the tungstate salt are compounded to form a strong oxidizing phosphotungstic heteropoly acid, and then a more dense protective coating is formed, thereby improving the corrosion resistance and insulation of the coating; in the scheme, aluminum dihydrogen phosphate and zinc dihydrogen phosphate are further selected for compounding, and the zinc dihydrogen phosphate serves as an auxiliary film-forming material, which can adjust the thickness of the coating, and the amount of addition should not be too much to avoid affecting the adhesion of the coating.

[0024] Further, the auxiliary agent includes the following components, by weight fraction: 1-3 parts of a defoaming agent, and 1-3 parts of a leveling agent.

[0025] Further, the curing agent includes, but is not limited to, any one of maleic anhydride and phthalic anhydride.

[0026] Further, the drying and curing are carried out at 100-120℃ for 30-60min, and then at 190-210℃ for 1-2h.

[0027] Compared with the prior art, the present application has the advantages that: the present application introduces the synergistic film forming of epoxy resin, phosphate and tungstate, thereby making the coating and the substrate more closely combined; the epoxy resin is further modified to improve the mechanical properties of the coating and make it have better weather resistance, which can adapt to more severe environments; at the same time, the compatibility of the modified epoxy resin, the epoxy propyl methacrylate copolymer and the modified filler is enhanced, thereby improving the performance of the coating and enhancing the moisture resistance, wear resistance, corrosion resistance and insulation of the coating, and the epoxy propyl methacrylate copolymer can resist static electricity, reduce iron loss, better protect the transformer core, thereby stabilizing the precision of the transformer core, and thereby making the transformer play an active role in the power system. DETAILED DESCRIPTION

[0028] The following describes the preferred embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. For ordinary skilled in the art, all other embodiments obtained without creative labor under the premise of not departing from the principles of the embodiments of the present application, belong to the scope of protection of the present application.

[0029] Preparation of activated boron nitride: 10 parts of nano boron nitride, 50 parts of 25wt% sodium hydroxide solution were added into a ball mill, and treated by ball milling at a speed of 350rpm for 48h. After filtration, washing and drying, activated boron nitride was obtained.

[0030] Filler: nano silicon dioxide and activated boron nitride were mixed in a mass ratio of 1:3.

[0031] Example 1: Preparation method of high-precision core for wind power water-cooled transformer:

[0032] Step one: the core for wind power water-cooled transformer was placed in an acetone solution and ultrasonically cleaned for 15min, then washed with distilled water for 2 times, and dried for standby use;

[0033] Step two: 1. Preparation of modified epoxy resin: 50 parts of bisphenol A type epoxy resin and 0.03 parts of hydroquinone were added into a reaction container and mixed uniformly, 12 parts of methacrylic acid and 1 part of N,N'-dimethyl aniline were added dropwise into the container at 75℃, and after the dropwise addition was completed, the reaction was continued for 4h to obtain the modified epoxy resin;

[0034] 2. Preparation of glycidyl methacrylate copolymer: (1) Under nitrogen protection, 4 parts of dodecafluoroheptyl methacrylate, 12 parts of glycidyl methacrylate, 0.04 parts of ethyl 2-bromoisobutyrate, 0.01 parts of copper chloride, 0.10 parts of tris(2-dimethylaminoethyl)amine, 0.10 parts of azobisisobutyronitrile, and 8 parts of ethyl acetate were sequentially added to a reaction vessel and mixed uniformly, and then stirred at 70℃ for 10h, and then distilled under reduced pressure to obtain product A; (2) Under nitrogen protection, 0.01 parts of 4-methoxyphenol and 5 parts of piperazine were added to a reaction vessel and mixed uniformly, and then the temperature was adjusted to 75℃, and then 12 parts of product A was added dropwise to the vessel under stirring, and then after the dropwise addition was completed, the reaction was continued for 3h, and then 8 parts of methyl methanesulfonate was added dropwise to the vessel, and then stirred for 2h, and finally distilled under reduced pressure to obtain the glycidyl methacrylate copolymer;

[0035] 3. Preparation of modified filler: (1) 20 parts of filler was added to 100 parts of 10wt% vinyltrimethoxysilane solution in anhydrous ethanol, and then after ultrasonic dispersion treatment at 50℃ for 1h, filtration, washing, and drying were performed to obtain a vinyl-modified filler; (2) 10 parts of the vinyl-modified filler, 15 parts of maleic anhydride, and 50 parts of anhydrous ethanol were mixed uniformly to obtain a reaction liquid C; (3) 1 / 2 volume of the reaction liquid C was added to a reaction vessel, 0.2 parts of dibenzoyl peroxide was added, and then after reflux stirring at 110℃ for 30min, the remaining 1 / 2 volume of the reaction liquid C was slowly added dropwise to the reaction system, and then after the dropwise addition was completed, the reaction was continued for 3h, and then the reaction was ended, and then the reaction system was naturally cooled to room temperature, and then distilled under reduced pressure, washed, and dried to obtain the modified filler;

[0036] 4. 40 parts of modified epoxy resin, 12 parts of glycidyl methacrylate copolymer, 15 parts of modified filler, 40 parts of aluminum dihydrogen phosphate, 10 parts of zinc dihydrogen phosphate, 2 parts of sodium tungstate, 30 parts of ethyl acetate, 1.5 parts of HR-3008 defoaming agent, 1.5 parts of HR-6031D leveling agent, and 15 parts of phthalic anhydride were mixed uniformly to obtain a protective coating;

[0037] 5. The protective coating was coated onto a core for a wind power water-cooled transformer, and then baked at 110℃ for 60min, and then cured at 200℃ for 90min to obtain a high-precision core for a wind power water-cooled transformer.

[0038] Example 2: Preparation method of high-precision core for a wind power water-cooled transformer:

[0039] Step one: The core for a wind power water-cooled transformer was placed into an acetone solution and ultrasonically cleaned for 15min, and then washed with distilled water for 2 times, and then dried for standby use;

[0040] Step two: preparation of modified epoxy resin: 50 parts of bisphenol A type epoxy resin, 0.03 parts of hydroquinone were added into a reaction container and mixed uniformly, 10 parts of methacrylic acid and 1 part of N, N'-dimethyl aniline were added into the container dropwise at 75℃, after the dropwise addition was completed, the reaction was continued for 3h, and the modified epoxy resin was obtained;

[0041] 2. Preparation of epoxy propyl methacrylate copolymer: (1) Under nitrogen protection, 4 parts of dodecafluoroheptyl methacrylate, 10 parts of epoxy propyl methacrylate, 0.04 parts of ethyl 2-bromoisobutyrate, 0.01 parts of copper chloride, 0.10 parts of tris(2-dimethylaminoethyl)amine, 0.10 parts of azobis isobutyronitrile, 8 parts of ethyl acetate were sequentially added into a reaction container and mixed uniformly, stirred at 70℃ for 10h, and then distilled under reduced pressure to obtain product A; (2) Under nitrogen protection, 0.01 parts of 4-methoxyphenol, 5 parts of piperazine were added into a reaction container and mixed uniformly, the temperature was adjusted to 75℃, 12 parts of product A was added into the container dropwise under stirring, after the dropwise addition was completed, the reaction was continued for 3h, then 8 parts of methyl methanesulfonate was added into the container dropwise, stirred for 2h, and finally distilled under reduced pressure to obtain epoxy propyl methacrylate copolymer;

[0042] 3. Preparation of modified filler: (1) 20 parts of filler was added into 50 parts of 10wt% vinyltrimethoxysilane solution in anhydrous ethanol, after ultrasonic dispersion treatment at 50℃ for 1h, filtration, washing and drying, the vinyl modified filler was obtained; (2) 10 parts of vinyl modified filler, 10 parts of maleic anhydride, 50 parts of anhydrous ethanol were mixed uniformly to obtain reaction liquid C; (3) 1 / 2 volume of reaction liquid C was added into a reaction container, 0.2 parts of dibenzoyl peroxide was added, after refluxing and stirring at 110℃ for 30min, the remaining 1 / 2 volume of reaction liquid C was slowly added into the reaction system, after the dropwise addition was completed, the reaction was continued for 3h, and then the reaction was ended, the reaction system was naturally cooled to room temperature, distilled under reduced pressure, washed and dried to obtain modified filler;

[0043] 4. 40 parts of modified epoxy resin, 12 parts of epoxy propyl methacrylate copolymer, 15 parts of modified filler, 40 parts of aluminum dihydrogen phosphate, 10 parts of zinc dihydrogen phosphate, 2 parts of sodium tungstate, 30 parts of ethyl acetate, 1.5 parts of HR-3008 defoaming agent, 1.5 parts of HR-6031D leveling agent, 15 parts of phthalic anhydride were mixed uniformly to obtain protective coating;

[0044] 5. The protective coating was coated on the iron core for wind power water-cooled transformer, baked at 110℃ for 60min, and then cured at 200℃ for 90min to obtain high-precision iron core for wind power water-cooled transformer.

[0045] Example 3: Preparation method of high-precision iron core for wind power water-cooled transformer

[0046] Step one: the core of the wind power water-cooled transformer is put into acetone solution for ultrasonic cleaning for 15 min, then washed with distilled water for 2 times, and dried for standby;

[0047] Step two: 1. Preparation of modified epoxy resin: 50 parts of bisphenol A type epoxy resin, 0.03 parts of hydroquinone are added into the reaction container and mixed uniformly, 15 parts of methacrylic acid and 1 part of N, N'-dimethyl aniline are added into the container dropwise at 75℃, after the dropwise addition is completed, the reaction is continued for 5h, and the modified epoxy resin is obtained;

[0048] 2. Preparation of methyl propenoxy propyl ester copolymer: (1) Under nitrogen protection, 4 parts of methyl propenoxy propyl ester, 15 parts of methyl propenoxy propyl ester, 0.04 parts of 2-bromoisobutyric acid ethyl ester, 0.01 parts of copper chloride, 0.10 parts of tris (2-dimethylaminoethyl) amine, 0.10 parts of azobis isobutyronitrile, 8 parts of ethyl acetate are sequentially added into the reaction container and mixed uniformly, stirred at 70℃ for 10h, and then distilled under reduced pressure to obtain product A; (2) Under nitrogen protection, 0.01 parts of 4-methoxyphenol, 5 parts of piperazine are added into the reaction container and mixed uniformly, the temperature is adjusted to 75℃, 12 parts of product A are added into the container dropwise under stirring, after the dropwise addition is completed, the reaction is continued for 3h, then 8 parts of methyl sulfonate are added into the container dropwise, stirred for 2h, and finally distilled under reduced pressure to obtain methyl propenoxy propyl ester copolymer;

[0049] 3. Preparation of modified filler: (1) 20 parts of filler are added into 100 parts of 10wt% vinyl trimethoxysilane solution in anhydrous ethanol, after ultrasonic dispersion treatment at 50℃ for 1h, filtration, washing and drying, the vinyl modified filler is obtained; (2) 10 parts of vinyl modified filler, 15 parts of maleic anhydride, 50 parts of anhydrous ethanol are mixed uniformly to obtain reaction liquid C; (3) 1 / 2 volume of reaction liquid C is added into the reaction container, 0.2 parts of dibenzoyl peroxide is added, after stirring and refluxing at 110℃ for 30min, the remaining 1 / 2 volume of reaction liquid C is slowly added into the reaction system, after the dropwise addition is completed, the reaction is continued for 3h, and the reaction is ended, after the reaction system is naturally cooled to room temperature, it is distilled under reduced pressure, washed and dried to obtain the modified filler;

[0050] 4. 40 parts of modified epoxy resin, 12 parts of methyl propenoxy propyl ester copolymer, 15 parts of modified filler, 40 parts of aluminum dihydrogen phosphate, 10 parts of zinc dihydrogen phosphate, 2 parts of sodium tungstate, 30 parts of ethyl acetate, 1.5 parts of HR-3008 defoaming agent, 1.5 parts of HR-6031D leveling agent, 15 parts of phthalic anhydride are mixed uniformly to obtain the protective coating;

[0051] 5. The protective coating is coated on the core of the wind power water-cooled transformer, baked at 110℃ for 60min, and then cured at 200℃ for 90min to obtain the high-precision core of the wind power water-cooled transformer.

[0052] Example 4: Based on Example 1, 40 parts of modified epoxy resin, 12 parts of epoxy propyl methacrylate copolymer, 15 parts of modified filler, 40 parts of aluminum dihydrogen phosphate, 10 parts of zinc dihydrogen phosphate, 0.5 parts of sodium tungstate, 30 parts of ethyl acetate, 1.5 parts of HR-3008 defoaming agent, 1.5 parts of HR-6031D leveling agent, 15 parts of phthalic anhydride are uniformly mixed to obtain a protective coating; other processes remain unchanged.

[0053] Example 5: Based on Example 1, 40 parts of modified epoxy resin, 12 parts of epoxy propyl methacrylate copolymer, 15 parts of modified filler, 40 parts of aluminum dihydrogen phosphate, 10 parts of zinc dihydrogen phosphate, 10 parts of sodium tungstate, 30 parts of ethyl acetate, 1.5 parts of HR-3008 defoaming agent, 1.5 parts of HR-6031D leveling agent, 15 parts of phthalic anhydride are uniformly mixed to obtain a protective coating; other processes remain unchanged.

[0054] The following is based on Example 1, a control experiment is carried out, specifically Comparative Examples 1-5, as follows:

[0055] Comparative Example 1: Comparative Example 1 is based on Example 1, adjusted as follows: no sodium tungstate is added, specifically:

[0056] 40 parts of modified epoxy resin, 12 parts of epoxy propyl methacrylate copolymer, 15 parts of modified filler, 40 parts of aluminum dihydrogen phosphate, 10 parts of zinc dihydrogen phosphate, 30 parts of ethyl acetate, 1.5 parts of HR-3008 defoaming agent, 1.5 parts of HR-6031D leveling agent, 15 parts of phthalic anhydride are uniformly mixed to obtain a protective coating; other processes remain unchanged.

[0057] Comparative Example 2: Comparative Example 2 is based on Example 1, adjusted as follows: no zinc dihydrogen phosphate is added, specifically:

[0058] 40 parts of modified epoxy resin, 12 parts of epoxy propyl methacrylate copolymer, 15 parts of modified filler, 50 parts of aluminum dihydrogen phosphate, 2 parts of sodium tungstate, 30 parts of ethyl acetate, 1.5 parts of HR-3008 defoaming agent, 1.5 parts of HR-6031D leveling agent, 15 parts of phthalic anhydride are uniformly mixed to obtain a protective coating; other processes remain unchanged.

[0059] Comparative Example 3: Comparative Example 3 is based on Example 1, adjusted as follows: the epoxy resin is not modified, specifically:

[0060] 40 parts of bisphenol A type epoxy resin, 12 parts of epoxy propyl methacrylate copolymer, 15 parts of modified filler, 40 parts of aluminum dihydrogen phosphate, 10 parts of zinc dihydrogen phosphate, 2 parts of sodium tungstate, 30 parts of ethyl acetate, 1.5 parts of HR-3008 defoaming agent, 1.5 parts of HR-6031D leveling agent, 15 parts of phthalic anhydride are uniformly mixed to obtain a protective coating; other processes remain unchanged.

[0061] Comparative Example 4: Comparative Example 4 is based on Example 1, adjusted as follows: no epoxy propyl methacrylate copolymer is added, specifically:

[0062] 40 parts of modified epoxy resin, 15 parts of modified filler, 40 parts of aluminum dihydrogen phosphate, 10 parts of zinc dihydrogen phosphate, 2 parts of sodium tungstate, 30 parts of ethyl acetate, 1.5 parts of HR-3008 defoaming agent, 1.5 parts of HR-6031D leveling agent, 15 parts of phthalic anhydride are uniformly mixed to obtain a protective coating; other processes remain unchanged.

[0063] Comparative Example 5: Comparative Example 5 is based on Example 1, adjusted as follows: only activated boron nitride is introduced as filler, specifically:

[0064] 40 parts of modified epoxy resin, 12 parts of epoxy propyl methacrylate copolymer, 15 parts of modified boron nitride, 40 parts of aluminum dihydrogen phosphate, 10 parts of zinc dihydrogen phosphate, 2 parts of sodium tungstate, 30 parts of ethyl acetate, 1.5 parts of HR-3008 defoaming agent, 1.5 parts of HR-6031D leveling agent, 15 parts of phthalic anhydride are uniformly mixed to obtain a protective coating; other processes remain unchanged.

[0065] In the above examples, all raw materials are as follows: the core material for wind power water-cooled transformer is B50AH300 type high-efficiency non-oriented silicon steel (Shanghai Baidas Industry Co., Ltd.); bisphenol A type epoxy resin purity 99%, model E-51 (Jinan Chuangshi Chemical Co., Ltd.); epoxy propyl methacrylate purity 99%, item number: S60373 (Shanghai Yuanye Bio-Technology Co., Ltd.); dodecafluoroheptyl methacrylate purity 99%, item number: HC1367 (Tianmen Hengchang Chemical Co., Ltd.); 2-bromoethyl isobutyrate purity 99% (Wuhan Xinxinjiali Biological Technology Co., Ltd.); tris(2-dimethylaminoethyl)amine purity 98% (Shanghai Yuanye Bio-Technology Co., Ltd.); 4-methoxyphenol purity 98% (Shanghai Yuanye Bio-Technology Co., Ltd.); piperazine purity 99% (Shanghai Biyang Industry Co., Ltd.); methyl methylsulfonate purity 99% (Hubei Yongkuo Technology Co., Ltd.); nano silicon dioxide purity 99%, particle size 7-12 nm (Zhejiang Manli Nanometer Technology Co., Ltd.); maleic anhydride purity 99.5% (Jinan Jinhu Chemical Co., Ltd.); nano boron nitride purity 99.9%, particle size 5-10 nm (Yumu (Ningbo) New Material Co., Ltd.); aluminum dihydrogen phosphate purity 95%, item number: S42226 (Shanghai Yuanye Bio-Technology Co., Ltd.); zinc dihydrogen phosphate purity 99%, item number: 003 (Hubei Chengfeng Chemical Co., Ltd.); sodium tungstate purity 99% (Wuhan Nengren Pharmaceutical and Chemical Co., Ltd.); HR-3008 defoamer (Dongguan Hongrui Chemical Co., Ltd.); HR-6031D leveling agent (Dongguan Hongrui Chemical Co., Ltd.); phthalic anhydride purity 99% (Hebei Moju Biological Technology Co., Ltd.).

[0066] Performance test: the high-precision core for wind power water-cooled transformer obtained in examples 1-5 and comparative examples 1-5 was subjected to coating anti-peeling performance test, corrosion resistance test, and insulation test, and was compared with the uncoated core for wind power water-cooled transformer, and the specific data are shown in table 1:

[0067] 1. Anti-peeling performance test: according to the test standard of GB / T 9286-2021, the core to be tested was subjected to grid marking, and then the adhesive tape was suddenly peeled off, and the coating film condition at the grid marking position was observed;

[0068] 2. Corrosion resistance test: neutral salt spray accelerated corrosion test was adopted, JH-60 type salt spray corrosion test box was used, and the test standard of GB / T10125-2012 was adopted; test conditions: (1) pure sodium chloride aqueous solution: concentration 50 g / L, pH value 6.5; (2) test temperature: 35℃; (3) salt spray deposition amount: 2 mL / h·80 cm 2(4) sample placement: the experimental surface is at an angle of 30° to the vertical; 1 h is taken as a cycle, continuous spraying is performed in each cycle, the sample is checked once at the end of each cycle, the checking time is not more than 10 min, the corrosion area after 8 h is measured to evaluate the corrosion resistance, and the evaluation is performed according to the following standards:

[0069] (1) the corrosion area is 0% after 8 h of salt spray test, and the corrosion resistance grade is excellent;

[0070] (2) the corrosion area is 0 < S ≤ 5% after 8 h of salt spray test, and the corrosion resistance grade is good;

[0071] (3) the corrosion area is 5 < S after 8 h of salt spray test, and the corrosion resistance grade is poor;

[0072] 3. Insulation test: the interlayer resistance of the iron core is measured by using an insulation resistance tester according to the method specified in GB / T 2522-2017 to evaluate the insulation, and the evaluation is performed according to the following standards:

[0073] (1) the interlayer resistance is > 30 Ω / cm 2 , and the insulation is excellent;

[0074] (2) the interlayer resistance is 5-30 Ω / cm 2 , and the insulation is good;

[0075] (3) the interlayer resistance is < 5 Ω / cm 2 , and the insulation is poor;

[0076] Table 1

[0077]

[0078] Conclusion: from the above table 1, it can be seen that the protective coating prepared by the application has good anti-peeling performance, and also has corrosion resistance, which has obvious protective effect on the transformer iron core; in addition, the coating has good insulation and can resist static electricity, which can better protect the transformer and avoid potential difference to cause damage to the transformer; that is, the protective coating prepared by the application can play a role in protecting the transformer iron core, and then maintain the precision of the transformer iron core, so that the transformer can play an active role in the power system.

[0079] Finally, it should be noted that: the above only describes the preferred embodiments of the application, but the protection scope of the application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the application, which should be covered in the protection scope of the application; the embodiments and the features in the embodiments can be combined with each other without conflict. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

Claims

1. A method for manufacturing a high-precision iron core for a wind power water-cooled transformer, characterized in that: Includes the following steps: Step 1: Clean the core of the wind power water-cooled transformer and dry it for later use; Step 2: Apply the protective coating to the core of the wind power water-cooled transformer, and allow it to dry and cure to obtain the high-precision core of the wind power water-cooled transformer. The protective coating comprises the following components, by weight: 35-50 parts modified epoxy resin, 10-15 parts epoxy methacrylate copolymer, 10-20 parts modified filler, 50 parts phosphate, 0.5-5 parts tungstate, 30-40 parts ethyl acetate, 2-6 parts additives, and 10-20 parts curing agent, wherein the amount of tungstate added is 1-10% of the mass of phosphate; The modified epoxy resin is prepared as follows: the following components are in parts by weight: 50 parts of bisphenol A epoxy resin and 0.01-0.03 parts of hydroquinone are added to a reaction vessel and mixed. At 50-80°C, 10-15 parts of methacrylic acid and 1-2 parts of N,Nˋ-dimethylaniline are added dropwise to the vessel. After the addition is complete, the reaction continues for 3-5 hours to obtain the modified epoxy resin. The preparation method of the glycidyl methacrylate copolymer is as follows: the following components are in parts by weight: (1) Under nitrogen protection, 3-5 parts of dodecafluoroheptyl methacrylate, 10-15 parts of glycidyl methacrylate, 0.03-0.05 parts of ethyl 2-bromoisobutyrate, 0.01-0.02 parts of copper chloride, 0.08-0.12 parts of tris(2-dimethylaminoethyl)amine, 0.10-0.12 parts of azobisisobutyronitrile, and 6-10 parts of ethyl acetate were added sequentially into a reaction vessel and mixed. The mixture was stirred at 60-80°C for 6-12 hours. The product A was obtained by vacuum distillation. (2) Under nitrogen protection, 0.01-0.02 parts of 4-methoxyphenol and 3-6 parts of piperazine were added to the reaction vessel and mixed. The temperature was adjusted to 50-85℃. 10-18 parts of product A were added dropwise to the vessel while stirring. After the addition was complete, the reaction continued for 2-3 hours. Then, 5-10 parts of methyl methanesulfonate were added dropwise to the vessel and the reaction was stirred for 2-3 hours. Finally, the product was obtained by vacuum distillation. The modified filler is prepared as follows: the following components are in parts by weight: (1) Add 10-20 parts of filler to 50-100 parts of 10wt% vinyl silane coupling agent in anhydrous ethanol solution, and ultrasonically disperse at 40-60℃ for 1-2 hours. After filtration, washing and drying, vinyl-modified filler is obtained. (2) Mix 10 parts of vinyl-modified filler, 10-20 parts of maleic anhydride and 50 parts of anhydrous ethanol evenly to obtain reaction solution C; (3) Take 1 / 2 volume of reaction solution C and add it into the reaction vessel. Add 0.1 to 0.3 parts of benzoyl peroxide. Stir and reflux at 100 to 120°C for 20 to 40 minutes. Then, slowly add the remaining 1 / 2 volume of reaction solution C to the reaction system. After the addition is complete, continue the reaction for 2 to 4 hours. Stop the reaction and let the reaction system cool naturally to room temperature. Then, distill under reduced pressure, wash and dry to obtain the modified filler. The filler is obtained by mixing nano-silica and activated boron nitride in a mass ratio of 1:(1-3).

2. The method for preparing a high-precision iron core for a wind power water-cooled transformer according to claim 1, characterized in that: The activation method of the activated boron nitride is as follows: the following components are in parts by weight: add 10 parts of nano boron nitride and 40-100 parts of 25wt% sodium hydroxide solution to a ball mill, and ball mill at a speed of 200-500 rpm for 24-48 hours. After filtration, washing and drying, activated boron nitride is obtained.

3. The method for preparing a high-precision iron core for a wind power water-cooled transformer according to claim 1, characterized in that: The phosphates include one or more of aluminum dihydrogen phosphate, zinc dihydrogen phosphate, calcium dihydrogen phosphate, nickel dihydrogen phosphate, and magnesium dihydrogen phosphate; the tungstates include one or more of sodium tungstate, potassium tungstate, and ammonium tungstate.

4. The method for preparing a high-precision iron core for a wind power water-cooled transformer according to claim 3, characterized in that: The phosphate is a composition of aluminum dihydrogen phosphate and zinc dihydrogen phosphate, wherein the mass ratio of aluminum dihydrogen phosphate to zinc dihydrogen phosphate is (3-5):

1.

5. The method for preparing a high-precision iron core for a wind power water-cooled transformer according to claim 1, characterized in that: The additives include the following components, by weight: 1-3 parts defoamer, 1-3 parts leveling agent; the curing agent includes any one of maleic anhydride and phthalic anhydride.

6. The method for preparing a high-precision iron core for a wind power water-cooled transformer according to claim 1, characterized in that: The drying and curing process involves drying at 100–120°C for 30–60 minutes, followed by curing at 190–210°C for 1–2 hours.

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