JPH0410687B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel method for manufacturing busbar insulated conductors using electrophoresis. Generally, a large number of power transmission lines or distribution lines are connected to a substation to interconnect, centralize, and distribute electric power, and these transmission and distribution lines consist of transformers, phase adjustment equipment, circuit breakers, and disconnectors. It is connected to the busbar with switching equipment. Therefore, since the bus bar is used under large current and high voltage, insulation of the bus bar is important, and various methods have been adopted for insulating the bus bar. Conventionally, bus insulated conductors are made by coating bare conductors made of copper in an electrodeposition paint solution in which mica powder, an inorganic insulator, and water-dispersible varnish, an organic insulator, are dispersed in water. immersion, and form an electrodeposited insulating layer on the bus conductor by electrophoresis,
It is produced by heating and drying, impregnating with an impregnating resin composition containing a curing agent, etc., and heating and curing. The mica powder is used together with a moisture-acidic varnish because the strength of the electrodeposited mica powder alone is poor, and when the object to be coated is removed from the electrodeposited paint, the mica powder falls off, making it difficult to use in practice. This is to allow the mica powder to act as a binder in the water-dispersed varnish. Water-dispersible varnish is not intended to fill the gaps created between mica powders, but rather leaves gaps and impregnates them with an impregnating resin composition according to the purpose and uses them as an insulating layer. It will be done. Generally, after being impregnated with an impregnating resin, it is heated and cured, but at that time, the viscosity of the impregnated resin composition decreases,
A so-called sag phenomenon occurs, voids are formed in the insulator, and the adhesion of the impregnated resin to the coated surface is reduced, making it impossible to obtain a busbar insulated conductor with good insulation performance. Further, since the impregnated resin composition contains a curing agent, the pot life is inevitably limited, and maintenance of the impregnated resin composition storage tank is complicated and uneconomical. As a result of intensive research to improve these drawbacks, the inventors of the present invention found that copper was added to the electrodeposition paint liquid obtained by dispersing mica powder, an inorganic insulator, and water-dispersible varnish, an organic insulator, in water. An electrical conductor for a bus bar made of material is immersed, an electrodeposition insulation tank is formed on the electrical conductor by electrophoresis, and after drying by heating, it is immersed in a water-soluble resin solution containing a hardening agent for the impregnating resin. It has been found that various defects can be solved by heating and drying, then impregnating with an impregnating resin and heating and curing. That is, in the present invention, an electrodeposited insulation tank is formed on the electrical conductor, and after being heated and dried, it is immersed in a water-soluble resin solution, and after being heated and dried, it is impregnated with an impregnated resin and heated and hardened, thereby preventing the dripping phenomenon. The adhesion of the impregnated resin to the painted surface is improved, and a busbar insulated conductor with extremely stable quality can be obtained. The remarkable effect of eliminating the complexity and uneconomical nature of maintenance was achieved. The water-dispersible varnish resin used in the present invention may be any water-dispersible varnish resin that can be electrodeposited, and suitable examples include acrylic resins and epoxy ester resins. The mica powder used in the present invention has a particle size of
Those that do not pass through a 200-mesh sieve but pass through a 20-mesh sieve, particularly those that pass through a 35-mesh sieve, are preferred. The blending amount is 100 parts of mica powder (parts by weight,
5 to 30 parts of water-dispersible varnish resin is suitable. When the electrodeposition paint used in the present invention is made by mixing 100 parts of mica powder with 5 to 30 parts of a water-dispersible varnish resin, the bus bar insulation has excellent thermal, electrical and mechanical properties. I can get a body. As the water-soluble resin used in the present invention, for example, acrylic resin is suitable, and the concentration of the solution is 5 to 15% (weight %, the same applies hereinafter), preferably 5 to 15%.
It is 10%. The curing agent contained in the water-soluble resin solution is preferably a water-soluble curing agent, such as organic amines such as triethanolamine or imidazoles such as 2-ethyl-4-methylimidazole (2E4Mz). The concentration in the water-soluble resin solution is 1 to 10%, preferably 1 to 6%. As the impregnating resin used in the present invention, known thermosetting resins used in general electrical equipment, such as epoxy resins and imide epoxy resins, are suitable. The electrodeposited insulating layer formed on the bus conductor is easily carried out by known electrodeposition techniques. In other words, as shown in FIG. 2, the electrical connection surface 2 of the copper conductor 1, which is made of a copper material and has a rectangular cross section and is the object to be coated, and which must not be electrodeposited, is coated with a commercially available electrical contact surface 2, as shown in FIG. 2. The bus conductor 1 is sealed with adhesive tape 3 and immersed in the electrodeposition paint 5 placed in the electrodeposition tank 4 as shown in FIG. An electrodeposition bath can be formed by using the DC power source 6 with the electrode as the cathode side. Furthermore, automation and labor saving can be implemented relatively easily using known automation techniques. Next, the method of the present invention will be explained with reference to Examples and Comparative Examples. Example 1 Epicote 1001 (manufactured by Ciel Chemical Co., Ltd.) 2900g,
100 g of ethylene glycol, 650 g of tetrahydrophthalic acid and 600 g of xylene were placed in a 5-four neck flask and reacted at 145-150° C. for about 1 hour while nitrogen was passed through the flask to obtain an acid-added epoxy resin with an acid value of about 50. Pour 30 g of lauryl sulfate ester soda and 25,000 g of ion-exchanged water into approximately 50 containers, heat while stirring, and prepare 500 g of 25% ammonia aqueous solution at 65-70℃.
g and 3,500 g of acid-added epoxy resin were added, emulsified, and stirred at 70°C for about 5 hours while distilling off excess ammonia water through inert gas (nitrogen gas), resulting in a mixture with a nonvolatile content of about 10% and a pH of about 7.5. An epoxy ester water-dispersible varnish was obtained. Into the epoxy ester-based water-dispersible varnish, add 80% mica powder that has passed through a 35-mesh mesh and thoroughly washed with ion-exchanged water to 20 parts of the resin content of the water-dispersible varnish.
15% of total nonvolatile content was prepared by adding ion-exchanged water and stirring well to uniformly disperse the mixture. The obtained electrodeposition paint 5 was placed in an electrodeposition tank 4 as shown in FIG. The electrically contacting surface 2 of the bus conductor 1 made of a copper material and having a rectangular cross section as shown in FIG. 1, which is the object to be coated, is sealed with an adhesive tape 3 as shown in FIG. It was immersed in the electrodeposition paint 5 of Bus conductor 1
DC voltage is applied with a distance between poles of 20cm using DC power supply 6.
A voltage of 100V was applied for 20 seconds, and then it was dried at 150°C for 15 minutes to obtain an electrodeposited insulating layer with a thickness of 1 mm. After immersing the obtained bus conductor having the electrodeposited insulating layer in a 5% aqueous acrylic resin solution containing 3% triethanolamine as a hardening agent,
It was dried at 150°C for 15 minutes. After that, an epoxy resin containing no curing agent (a mixture of 100 parts and 98 parts of Epon 828 (manufactured by Ciel Chemical Co., Ltd.) and HN2200 (manufactured by Hitachi Chemical Co., Ltd.)) was vacuum impregnated and cured at 150°C for 5 hours. Then I got the bus insulator. The obtained busbar insulator did not cause any epoxy resin dripping phenomenon and had extremely stable quality. Initial breakdown voltage of the bus insulated conductor (hereinafter referred to as
BDV) and after aging at 250℃ for 16 days.
BDV was measured. The results are shown in Table 1.

[Table] Example 2 A busbar insulated conductor was obtained in the same manner as in Example 1, except that the type of curing agent, its usage amount, and the concentration of water-soluble resin in Example 1 were changed as shown in Table 1. . The obtained busbar insulated conductor did not cause any epoxy resin dripping phenomenon and had extremely stable quality. Initial BDV of said bus insulated conductor and 250℃×16
BDV was measured after days of deterioration. The results are shown in Table 1. Comparative Example 1 A bus conductor having an electrodeposited insulating layer obtained in the same manner as in Example 1 was vacuum impregnated with an epoxy resin composition containing 100 parts/98 parts/1 part of Epon 828/HN2200/zinc octylate. Afterwards, it was cured at 150°C for 5 hours to obtain a busbar insulated conductor. The zinc octylate is an epoxy resin curing agent. Initial BDV and 250℃ of the obtained busbar insulated conductor
BDV was measured after ×16 days of deterioration. The results are shown in Table 1. Comparative Example 2 A 5 mm x 2 mm rectangular copper wire was immersed in a water-dispersed varnish containing mica, and a porous mica electrodeposition layer was provided on the conductor by electrodeposition. Then, on the electrodeposited layer,
A resin solution (5%) in which bisphenol A epoxy resin and tetrahydrophthalic anhydride were dissolved in acetone was impregnated and cured at 130°C for 10 hours to obtain a porous insulating layer. Further, a composition prepared by blending 1 part of 2-ethyl 4-methylimidazole as a curing catalyst with 100 parts of a solvent-free resin consisting of bisphenol A epoxy resin and tetrahydrophthalic acid was vacuum impregnated. The resulting conductor was placed in an oven at 130°C to cure, but much of the impregnated resin dripped off before curing was completed. When I measured the electrical characteristics, it was 1kV-5kV.
The change in tan δ between the layers, Δtan δ, was 5% (Δtan δ increases in proportion to the number of voids in the insulating layer, indicating a porous structure), and the curing rate in the insulating layer was slow, and the impregnated It was shown that the resin escaped from the insulating layer before it was cured.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of a bus conductor, Figure 2 is an explanatory diagram showing the electric contact surface of the bus conductor sealed with adhesive tape, and Figure 3 is an illustration of an electrodeposited insulating layer formed on the bus conductor. It is an explanatory diagram showing a state. (Main symbols in the drawing), 1: Bus conductor, 5: Electrodeposition paint

Claims (1)

[Scope of Claims] 1. An electrical conductor for a bus made of copper is immersed in an electrodeposition coating solution obtained by dispersing mica powder, which is an inorganic insulator, and water-dispersible varnish, which is an organic insulator, in water. Then, an electrodeposited insulating layer is formed on the electrical conductor by electrophoresis, and after being heated and dried, it is immersed in a water-soluble resin solution containing a hardening agent for the impregnating resin, heated and dried, and then impregnated with the impregnating resin. A method for producing a busbar insulated conductor, which comprises at least heating and curing the conductor. 2. The manufacturing method according to claim 1, wherein the electrodeposition coating uses a mixture of 100 parts by weight of mica powder and 10 to 50 parts by weight of a water-dispersible varnish resin. 3. The manufacturing method according to claim 1, wherein the water-soluble resin is an acrylic resin. 4. The manufacturing method according to claim 1, wherein the water-soluble resin concentration is 3 to 15% by weight. 5. The manufacturing method according to claim 1, wherein the curing agent is a water-soluble organic amine or imidazole. 6 The concentration of the curing agent in the water-soluble resin solution is 0.5
10. The manufacturing method according to claim 1, wherein the content is 10% by weight.