JPS58158807A - Method of producing strand insulated conductor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a power cable conductor, particularly a strand insulated conductor which is used for large-capacity power transmission and which reduces stone and skin effects.

Usually, stranded wires made by twisting together copper wires having a diameter of 2 to 3 cm are used for power cable conductors. After twisting, compression molding with rolls or the like is widely used to reduce the gaps between the strands and make them more compact. Furthermore, in large capacity conductors,
A required number of segmented conductors, which are formed by twisting strands of strands and compression-molded into a layered cross-sectional shape, are used in combination to form a circular cross-section. In such a divided conductor, each segment is often insulated by wrapping paper, Glasti, or Cteig between each segment.

In recent years, as the capacity of AC power transmission has increased, the size of conductors has become enormous. However, as the size of conductors increases, transmission losses due to the skin effect and proximity effect suddenly become more prominent, increasing to 6%. 1.1 It is essential to divide the conductor into multiple segments, insulate each segment as described above, and also insulate each strand to prevent current concentration on the surface of the conductor. It is considered a countermeasure.

Conventionally, there is an example of using enamel-covered copper wires as a method of insulating wires, but in order to withstand the processing steps of twisting the wires and compression molding after twisting, it is necessary to
It is not actually used because it requires an enamel coating with a thickness greater than 100 μm, making it extremely costly.

For this reason, attempts have been made to use copper wires with oxidized steel formed on their surfaces as a cheaper insulator.

Oxidized steel can be easily formed on the surface of copper wire by oxidizing it in the atmosphere at high temperatures, e.g., 300°C or higher, but the copper oxide film thus obtained is fragile and has poor adhesion, making it impractical. Instead, a wet method of chemical treatment in an alkaline aqueous solution with the aid of an oxidizing agent such as chlorous acid produces copper oxide, which does not consist of microcrystals and is relatively small. It has characteristics of excellent workability and adhesion.

However, even with such a copper oxide film, a film thickness of 2 to 3 μm or more is required in order to withstand processing such as twisting and compression molding, and forming such a thick film using a wet method takes a lot of effort. Since the process requires many chemicals and a long time, it is inevitable that the process will be expensive.

To improve this, ordinary steel cables without a copper oxide coating are twisted together, and then subjected to necessary processing such as compression molding, and then subjected to wet processing such as Kamiayu. It is also proposed that This method #iub Since the copper oxide film is formed after joining or compression molding, the film thickness may be thinner than when forming the copper oxide film before twisting or compression molding, but it still has an average bulk of 0.5^ The reason why the copper oxide film must be formed until the film thickness reaches the above value is that it is necessary to completely insulate the upper and lower adjacent wires, which is the most important step in wire insulation. Since the wires are in close contact with each other through twisting and compression molding, especially the wires that are adjacent to each other above and below the conductor, a copper oxide film is formed on the contact interface of the contact area to ensure complete contact. In order to electrically disconnect* the wires, it is necessary to use the action of ultrasonic waves, etc., and even if measures such as promoting the infiltration of the treatment liquid between the strands are used, trenches with an average film thickness of 0.5 m or more must be used. In order to form a copper oxide film with an average thickness of 0.5 JllI1 or more using a wet method, it still requires a large amount of chemicals and a long time, resulting in high costs.

The present invention was made as a result of intensive research in view of the current situation IIcfI/i, and provides an economical and highly productive method for manufacturing high-performance strand insulated conductors with great strand insulation effects. It is something.

That is, the present invention provides a stranded wire characterized in that a conductor made of twisted steel cables is maintained at 60 to 100°C in a wet state and then brought into contact with ammonia gas to form oxidized steel on the surface of the strand. Manufacturing method of insulated conductor: T@Yes.

In the present invention, a conductor made by twisting steel cables is not limited to the twisting method, but may include, for example, concentric alternate twisting, concentric codirectional twisting, etc. ) A multi-layer twisted) conductor, a collective twisted conductor, etc.], and also includes one in which such twisted) combined conductor is further compression-molded into a desired shape such as a fan-shaped cross section.

When the laminated conductor is held at 60 to 100°C in a wet state, a hydrophilic oxide layer is formed on the surface of the copper wire. Cyanmonia rapidly dissolves in the moisture on the surface of the copper wire, and when it comes into contact with ammonia, it quickly dissolves into the moisture on the surface of the copper wire, causing
It is thought that complex ions of Cu(NH3)4) are formed and the formation reaction of the copper oxide film is promoted.

K to maintain stranded conductor at 60-100℃ in wet condition
is kept in steam at 60-100°C, or
The twisted conductor may be wetted with water and then heated and held at 60 to 100°C, but the former method of holding it in water vapor at 60 to 100°C is preferable. Such treatment is generally carried out in a chamber. Since it is carried out by accommodating a cork-shaped twisted conductor, both water vapor and ammonia gas can be introduced in the form of gases, making it easy to operate. Furthermore, even when ammonia gas is introduced and removed, it is better to allow water vapor to coexist in order to further promote the oxidized steel film formation reaction.

In particular, it is preferable to use saturated steam at a temperature of 60 to 100° C., since the surface of the copper wire is always kept moist.

The temperature when holding the twisted conductor in a wet state is 60~
The temperature was set at 100°C because within this temperature range, a hydrophilic oxide layer effective for the subsequent copper oxide film formation reaction is generated. In other words, effective wood-philic oxides are not formed at either temperatures below 60°C or above 100°C.

According to the present invention, a thin hydrophilic oxide layer is formed on the surface of the copper wire, and the presence of this layer causes the adsorption of ammonia gas to occur rapidly and uniformly between the contact interfaces of the wires. 0.5 to 0.5 required for electrical insulation between contact interfaces.
A copper oxide film with a thickness of 2μ can be easily formed. Furthermore, lubricating oil and the like adhere to the conductor during twisting of the wires and compression molding, but the present invention process can be performed with such adherents remaining.

Next, the present invention will be explained using Examples and Comparative Examples.

Example 1 88 mild steel wires with a diameter of 2.3 mm were twisted together and compression molded into a fan-shaped cross section to obtain an untreated segment for a 6-part conductor with a small amount of lubricating oil still attached to the surface of the wires. . This untreated segment 7) was wound into a coil of 1h 120 m and placed in a chan-chan, saturated steam K3 at a temperature of 80°C.
It was held for 0 minutes. Next, ammonia gas was injected, and the ammonia concentration in the chamber was maintained at 5% for 24 hours.

Next, a portion of the segment thus obtained was cut and subjected to a cathodic reduction method (electrolyte solution 0.1N-KCl, 'at flow).
The average copper oxide film thickness was measured using O, 5ws Jy'cs2) and found to be 1.32μ.

In addition, the six segments obtained above were twisted together to make a six-divided conductor with a conductor cross-sectional area of 2000 x 2, and the direct current resistance value (tag C ) and 50 H, AC resistance value (R
, c) are measured respectively, and the skin effect coefficient is :== :a
The results of determining c1 are shown in the table below.

Example 2 Approximately 120 untreated segments identical to those used in Example 1
After winding wz into a coil and putting it into the chamber, the temperature is 6.
It was kept in saturated steam at 0°C for 60 minutes.

Next, ammonia gas was injected, and the ammonia concentration in the chamber was maintained at 2-2 for 24 hours.

Thereafter, the average copper oxide film thickness was measured in the same manner as in Example 1, and the result was 1.05 mm. The following table shows the results of measuring the skin effect coefficient r of a 6-segment conductor using the segments obtained in Example 2.

Example 3 Approximately 120 untreated segments identical to those used in Example 1
The coil of m is immersed in water Ll .

Thereafter, the average copper oxide film thickness was measured in the same manner as in Example 1, and the result was 1.01 μm. In addition, the results of measuring the skin effect coefficient r of the six-segment conductor using the segments obtained in Example 3 are shown in the following table.

Comparative Example Approximately 120 untreated segments identical to those used in Example 1
After W1 was wound into a coil shape and placed in a chamber, saturated steam at a temperature of 60°C and ammonia gas were simultaneously injected, and the ammonia concentration in the chamber was set to 3-2.
It was held for 4 hours.

Thereafter, the average copper oxide film thickness was measured in the same manner as in Example 1, and the result was a slope of 035. The following table shows the results of measuring the skin effect coefficient r of a 6-segment conductor using the segments obtained in this comparative example.

In the table, the bare conductor is a six-divided groove with a conductor cross section of &2000 x 2 obtained by twisting six untreated segments exactly the same as those used in Example 1 in the same manner as in Example 1.

When producing a segmented conductor with wire insulation according to the present invention, it is common to insulate each segment with wire and then twist the segments as required to form the segmented conductor, as shown in the embodiment. However, untreated segments may be twisted together to form segmented conductors and then treated according to the present invention to insulate the strands.

As described above, according to the present invention, it is possible not only to efficiently and easily form a copper oxide film necessary for electrical insulation between the contact interfaces of the contact parts of the strands of the twisted conductor, but also to Since it is not necessary to remove the organic film on the surface, there is no need to clean with organic solvents, and the process can be processed as is.0 Ordinary twisted conductors and compression-molded conductors are coated with a small amount of organic film such as lubricating oil on the copper wire. In the conventional wet oxidation treatment method, it was necessary to wash with an organic solvent such as toluene beforehand, which had the disadvantage of requiring a large amount of solvent and human power. As is clear from the example,
There is an advantage that the conductor after twisting or compression molding can be processed as is.

However, the copper oxide film obtained by the present invention is dense and has excellent adhesion to the copper interface, and also because there is almost no adhesion or adsorption of substances other than copper oxide, it does not cause a decrease in insulation properties. This is extremely advantageous in this respect.

Claims (4)

[Claims] (1) A conductor made of twisted copper wires is heated at 60°C under wet conditions.
A method for producing an insulated wire conductor, which includes maintaining the wire at a temperature of ~100°C and then contacting it with ammonia gas to form oxidized steel on the surface of the wire. (2) The method for manufacturing a wire insulated conductor according to claim 1, wherein the moist state is provided by water vapor. (3) The method for manufacturing a wire insulated conductor according to claim 1, wherein the wet state is provided by bringing the conductor into contact with water. (4) A method for manufacturing a strand insulated conductor according to claim 1, characterized in that saturated water vapor is allowed to coexist when bringing ammonia gas into contact with the conductor held in the moist state.