JPS6130676A - Manufacture of conductor consisting of insulated strands - Google Patents

Abstract

PURPOSE:To form uniformly an oxide film inhibiting an increase in AC resistance on the surface of a power cable having large capacity by immersing the stranded copper wires of the cable in water contg. oxygen and a surfactant. CONSTITUTION:An oxide film is formed on the surface of a power cable having large capacity obtd. by stranding copper wires to reduce the AC loss by a skin effect. O2 is dissolved in water contg. about 10ppm cationic surfactant such as quat. ammonium salt or alkylpyridium salt from a vapor phase system having >=0.4kg/cm<2> partial pressure of O2, and the cable is immersed in the water at 60-200 deg.C in a vessel. The internal pressure of the vessel is reduced to allow the water to penetrate the cable over the whole length and breadth, and an oxide film is formed on the surface of copper of the stranded wires of the cable to inhibit an increase in the AC resistance by a skin effect and to reduce the loss of power transmitted.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for producing a strand insulated conductor using an oxide film, which is used for the purpose of reducing AC loss due to the skin effect of large-capacity capacitors. .

[Prior Art] In recent years, a technique has been implemented in which an oxide film is formed on the surface of the wire of a large-capacity cable to suppress an increase in AC resistance due to the skin effect.

Large-capacity cable conductors are mainly made by twisting strands of wire to form segments with a fan-shaped cross section, and combining these segments to form a conductor with a circular cross section. The oxide film is uniform, adhesive, and wear resistant.

Although a coating with good electrical insulation is desired, it cannot withstand twisting or compression molding, so it is generally oxidized in the form of segments. Also, inside J of such a segment,
Many techniques are required to obtain an oxide film.

[Problems to be Solved by the Invention] Conventional methods for forming an oxide film on the surface of wires can be roughly divided into methods using an oxidizing liquid and methods using humidification.

As a method using an oxidizing liquid, for example, Japanese Patent Publication No. 59-19
As disclosed in Japanese Patent Publication No. 608 and Japanese Patent Publication No. 59-19609, a method is known in which a mixed aqueous solution of sodium chlorite and caustic soda is used as the oxidation treatment liquid. In this case, since the chemicals used are harmful, waste liquid treatment and exhaust treatment are required, which is highly dangerous and requires expense for treatment equipment. In addition, if sodium chlorite or caustic soda remains on the surface of the copper wire, it may cause patina or deteriorate the coating layer, so it must be cleaned with a large amount of water or with a high-speed water stream. Must be.

On the other hand, as a method using humidification, for example,
As disclosed in Japanese Patent Application Laid-open No. 19612 and Japanese Patent Application Laid-Open No. 57-210517, stranded copper wire is placed in a humidified atmosphere containing only water vapor, a humidified atmosphere containing sulfur or sulfur compounds, or a humidified atmosphere containing ammonia or aliphatic amine. It is known how to put Even in this case, if sulfur, ammonia, etc. are used, waste liquid treatment and exhaust treatment are required. Further, in a humidified atmosphere containing only water vapor, the oxidation reaction does not proceed sufficiently, and unevenness tends to occur in the oxide film. Furthermore, in the method using humidification, the reaction proceeds until the wire drawing lubricant and dirt remain on the surface of the wire, which is one reason why the oxide film is likely to be uneven.

The present invention was devised to effectively solve the above-mentioned problems, and the oxide film obtained by the methods disclosed in the above-mentioned publications has sufficient density for its use. , adhesion and strength, and the present invention has been devised to further improve these properties.

Means for Solving Problem E] The oxidation treatment atmosphere for the copper stranded wire, which is a conductor made of stranded wires, is water that contains a surfactant and dissolves oxygen. Further, in order to promote the oxidation reaction, the amount of dissolved oxygen is maintained above a predetermined value, and the water temperature of the oxidizing atmosphere is set within a predetermined range.

Although the surfactant is not particularly limited, there is a concern that anionic surfactants may cause patina due to residual Na+. Cationic activators such as quaternary ammonium salts and alkylpyridinium salts, nonionic activators such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenol ethers, sorbitan alkyl esters, polyoxyethylated polypropylene glycols, etc. It also significantly improves the uniformity of the oxide film, forming a smooth, glossy to semi-glossy film with good adhesion. Its electrical properties and wear resistance are also extremely good.

A concentration of about 10 ppm is sufficient.

At 1%, the test is good but remains sticky.

It goes without saying that these surfactants may be used in combination.

As for copper stranded wire, conductors for large-capacity cable cables are often divided into segmented conductors, which are made by combining 5- fan-shaped compression-molded segments into a circular shape with paper or plastic film inserted between each segment to insulate them. , the present invention is also implemented in this segment. As for your immediate needs,
Although not particularly necessary, cleaning with an organic solvent such as trichloroethane may be performed in any of the steps of stranding, stranding, and compression.

The first step is to install the copper strands inside the tank. In this case, it is preferable that the copper stranded wire be gripped, but it may be wound in a drum. It is also preferable to untwist the preform by twisting it in the opposite direction. Next, reduce the pressure inside the tank. Although reduced pressure is not necessarily required, reducing the pressure makes it easier for the inside of the stranded wire to be filled with water, and oxidation progresses to the inside in a short time. Next, fill the tank with water. This water supply may be a hot water supply. Next, add surfactant to the water in the tank. Oxygen is supplied so as to be dissolved in the water, and the oxygen partial pressure in the gas phase system on the supply side is set to be 0.4 ko/cs+ or more and parallel to the dissolved oxygen partial pressure in the water. Also, set the temperature of the water in the tank to -6=60°C or higher and lower than 200°C. In addition, the M cord partial pressure of the gas phase system is 0.4 kg/cn.
If it is less than +2, only a film of 1 μ- or less will be formed in one week. Also, if the water temperature in the tank is less than 60℃, the oxygen partial pressure will be 1
Even at 0 kg/cl, it is still less than 1 μm in one week. Furthermore, if the water temperature in the tank is 200°C or higher, the vapor pressure of the water will be 16 kg/am' or higher, causing problems such as increased pressure in the tank and danger. Finally, the stranded copper wire with the oxide film formed thereon is taken out from the tank and dried to complete the process.

[Action 1] The action of the surfactant improves the wettability of the surface of the copper wire with water, and by creating a uniform contact surface between the copper wire and water, a homogeneous oxide film is formed. Further, although the reason for the causal relationship is not clear, by adding a surfactant, the oxide film is smooth, dense, has a beautiful gloss, and has good adhesion.

It also has good electrical properties and excellent wear resistance.

Furthermore, it is difficult for water to penetrate into the copper strands;
Such an interior can also be filled with water by the action of a surfactant.

[Example] Preferred embodiments of the present invention will be described below.

Example 1 1191 steel cables with a diameter of 2.771111 were formed into fan-shaped segments with an apex angle of 60'. This was taken into a size of 3.5 mm in diameter and placed in a tank that can be pressurized and depressurized. After reducing the pressure inside the tank to 111111-1 (l), ion-exchanged water was injected to submerge the segment.

These segments were oxidized under the conditions shown in Table 1.

When six of these segments were twisted together and the skin effect coefficient was measured, the results shown in Table 1 were obtained.

In addition, the skin effect coefficient γ is γ-(AC resistance/DC resistance)-1 It is.

(Left below) Example 2 888 soft conductors with a diameter of 2,3111 were made into 6-layer segments with a space factor of 88% and an apex angle of 60''.

This was immersed in ion-exchanged water and oxidized for two weeks at 80', all elementary partial pressure 5 kg/a1. In addition, as a comparative example, the same segment was tested at an oxygen partial pressure of 5 kg/as2°80°C.
The oxide film thickness of each layer was measured by an electrolytic reduction method, and the results shown in Table 2 were obtained.

[Effects of the Invention] As is clear from the above description, the present invention provides the following excellent effects.

Since water is used as the oxidizing atmosphere for the copper stranded wire, waste liquid treatment and exhaust treatment are not required. Additionally, a small amount of surfactant is harmless to the cable properties, so water cleaning is not necessary. Furthermore, large quantities can be processed in batches. The resulting oxide film is smooth, uniform, dense, and has a glossy to semi-glossy appearance. Furthermore, the most important effects are adhesion, electrical properties,
Extremely good wear resistance.

Claims (4)

[Claims] (1) A conductor made of twisted copper wires is immersed in water containing dissolved oxygen and a surfactant, and an oxide film is formed on the copper wires by the dissolved oxygen in the water. A method for manufacturing a stranded insulated conductor. (2) The method for manufacturing a wire insulated conductor according to claim 1, wherein the water containing surfactant and dissolved oxygen is heated to 60 to 200°C. (3) The dissolved oxygen is supplied into the water from a gas phase system containing oxygen, and the oxygen partial pressure of the gas phase system is 0.4 kg/cm.
3. The method for producing a strand insulated conductor according to claim 1 or 2, wherein the partial pressure of dissolved oxygen in the water is balanced at ^2 or more. (4) The strand insulated conductor according to any one of claims 1 to 3, wherein the conductor is immersed in the water in a reduced pressure atmosphere, and the conductor is filled with the water. Production method.