JPH03173020A - Element-wire insulated conductor manufacture - Google Patents

Abstract

PURPOSE:To prevent the formation of a partly poor oxide film on the surface of each of copper element-wires so as to form a uniform oxide film all over the length of the copper twisted element-wire conductor by heating a copper twisted element-wire conductor and then bringing it into contact with an oxidizing reaction gas of a temperature higher than its temperature to form an oxide film on its surface at a point of the time when its temperature rise rate becomes steady. CONSTITUTION:When a copper conductor is started to be brought into contact with an oxidizing reaction gas in such a condition that the temperature rise rate of the conductor does not reach its steadiness, copper hydroxide may be generated because the conductor temperature is too low to sufficiently advance the film-forming reaction of copper oxide. In order to satisfactorily advance the oxidizing reaction, a preferable gas contact start temperature of the conductor is specified to range from 30 deg.C to 35 deg.C. When the copper twisted element-wire conductor is brought into contact with the oxidizing reaction gas to form an oxide film, it is brought into contact with the oxidizing reaction gas in such a condition that the temperature rise rate of the copper twisted element-wire conductor itself becomes steady. The oxidizing reaction of the surface of each of copper element-wires may thus be advanced quickly to satisfactorily form the copper oxide film.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing a strand insulated conductor useful as a low-loss conductor for large cables.

(Prior Art) As the demand for electric power increases, the conductors of power cables are becoming larger.

When large-capacity power transmission is performed using a large cable, alternating current resistance increases due to the skin effect of the conductors that make up the cable, so methods to reduce this are being studied.

For example, when a conductor with a cross-sectional area of 1000 mm2 or more is used as a low-loss conductor, a segment conductor is produced by twisting copper wires together and compression-molding the cross-sectional shape into a sector shape.
A divided conductor is used in which a required number of segment conductors are assembled to form a circular cross-sectional shape.

Furthermore, we insulate each segment with insulating tape, etc., and also insulate each copper wire that makes up the segment.
Prevents concentration of current on the surface layer of the conductor.

As a method for insulating copper wire, it is known to form a black oxide film on the surface of the copper wire, and such wire insulated conductors are manufactured by treating the segment conductor units with an oxidizing solution (for example, NaCl02 + Na011 solution, 112 0
2+1lNO! There is a wet method in which the conductor is immersed in a solution (such as a solution) to form a CuO film on the surface of the copper wire through a liquid phase reaction, or a conductor is heated in an ammonia atmosphere to form a CuO film on the surface of the copper wire through a gas phase reaction.
It is manufactured by a dry method that forms a uO film.

(Problem to be solved by the invention) The oxide film described above is thinner than enamel films and has excellent electrical and mechanical properties, and is expected to be widely applied. It is something.

However, oxidation treatment of copper bare wire conductors is usually carried out by winding the conductor around a drum, and in this drum winding method, a long conductor is wound around the drum for t11 times. A phenomenon occurs in which the conductors come into contact with each other, and sufficient oxidizing reaction gas or oxidizing reaction solution does not penetrate into this contact area.

For this reason, there is a problem that the CuO film formed on the surface of the copper wire becomes non-uniform as a whole, and unnecessary components (for example, copper hydroxide, etc.) are generated on a part of the copper wire.

In addition, even if the conductor part has a well-formed oxide film, if the total length of the conductor is longer than 100W, the film will be easily damaged by rubbing or bumping due to contact between the conductors when sent to the next process, resulting in poor insulation and reliability. It is the cause of sexual decline.

Therefore, in order to improve the reliability of bare wire insulated conductors, it is necessary to eliminate partial oxidation reaction failures due to contact between conductors during drum winding, and at the same time prevent loss of 1u of oxide film due to contact between conductors. It becomes.

The present invention has been made to solve these problems, and aims to prevent the formation of a partial oxide film on the surface of a copper wire conductor and form a uniform oxide film over the entire length of the copper wire conductor. The purpose of the present invention is to provide a method for manufacturing a stranded insulated conductor that can achieve the following.

[Structure of the Invention] (Means for Solving the Problems) The method for manufacturing a stranded insulated conductor of the present invention involves heating a copper stranded conductor made by twisting copper strands together, and by this heating, the first 32 copper stranded conductor When the temperature increase rate becomes steady, the stranded copper wire conductor is brought into contact with an oxidizing reaction gas at a temperature higher than the temperature of the stranded copper wire conductor to form an oxide film on the surface of the copper wire conductor. It is characterized by this.

In the present invention, a segment conductor obtained by compression molding a normal copper stranded conductor or a #4 stranded conductor using a roll or the like is placed in, for example, a sealed heating device and heated.

Aqueous ammonia is usually used to generate the oxidation reaction gas, and it is placed in a separate chamber within the sealed heating container and is not brought into contact with the conductor immediately after heating starts, so that the temperature rise rate of the conductor reaches a steady state. At that point, gas is introduced to cause the oxidation reaction to occur.

Alternatively, the oxidation reaction gas is generated in a device completely separate from the conductor heating device, and once the temperature increase rate of the conductor becomes steady,
The oxide film may be formed by blowing gas into the conductor heating device.

If contact with the oxidizing reaction gas is started before the heating rate of the conductor has reached a steady state, the temperature is too low for the copper oxide film formation reaction to proceed sufficiently, so if the conductor is exposed to the gas for a long time at such a low temperature, Upon contact, copper hydroxide is produced.

In order to promote the oxidation reaction favorably, a more preferable gas contact initiation temperature is a conductor temperature in the range of 30'C to 35C.

(Function) When the length of the copper stranded wire conductor is long, there will be a difference in the rate of temperature rise between the ambient temperature inside the heating container and the temperature of the conductor itself, and even if the temperature of the atmosphere has risen sufficiently at the beginning, A phenomenon occurs in which the temperature of the conductor does not rise sufficiently.

At this time, if the conductor comes into contact with the oxidizing reaction gas, the conductor itself will be in contact with the oxidizing reaction gas for a long time before it reaches a temperature sufficient to react sufficiently, resulting in the formation of copper hydroxide. .

Therefore, in the present invention, when an oxide film for insulation is formed on a copper stranded wire conductor by contacting it with an oxidizing reaction gas, the heating rate of the copper stranded wire conductor itself becomes steady. I am in contact with it.

As a result, the oxidation reaction on the surface of the copper wire progresses rapidly, and only the desired oxidized steel is formed satisfactorily.

(Example) Next, examples of the present invention will be described.

Example 3000ff1112 cross-sectional area length 200I1
A 1 Noah split conductor was wrapped around a drum and placed in a chamber within the heating device.

Furthermore, 596 ammonia water for generating oxidation reaction gas was placed in a separate chamber of this heating device.

This separate room is provided with a gas inlet that communicates with the room in which the seven-part conductor is arranged.

Thereafter, heating was started in the heating device from 25° C. at a temperature increase rate of 5° C./h, and at the same time an oxidizing reaction gas was generated from 5% ammonia water, all conductor temperatures were determined.

After the temperature rise started, when the IH rate of the conductor became steady and the conductor temperature rose to 31"C, an oxidizing reaction gas was introduced from a separate room of the heating device, brought into contact with the conductor, and the formation of an oxidized steel film was started. .

The heating device continued to raise the temperature to 80° C., and the oxidation treatment was performed for about 10 hours.

In the stranded insulated conductor thus obtained, a black oxide film was well formed on the entire surface of the copper strand, and no formation of hydroxide steel was observed.

Comparative Example A 7-segment conductor of length 20 (1 m) with a cross-sectional area of 300011 m 2 was wound around a drum and placed in a heating device.

Furthermore, 5% ammonia water for generating an oxidation reaction gas was placed in this heating device, separated from the conductor.

After that, the inside of the heating device was heated from 25℃ to 5℃/! Heating is started at a rising rate of 1H to generate an oxidizing reaction gas from 5% ammonia water, and at the same time, before the heating rate of the conductor reaches a steady state, the conductor is brought into contact with the oxidizing reaction gas to form a copper oxide film. began to form.

The heating device continued to raise the temperature to 80° C., and the oxidation treatment was performed for about 10 hours.

In the stranded insulated conductor thus obtained, a black oxide film was formed on the surface of the copper strand, while blue-green hydroxide steel was formed.

As is clear from these results, the wire insulated conductor fabricated using the conventional method of bringing the conductor and the oxidizing reaction gas into contact immediately at the same time as the heating starts in the heating device produces copper hydroxide in addition to copper oxide, causing electrical While a decrease in insulation was observed, the wire insulated conductor produced by the method of the example did not produce copper hydroxide, and a copper oxide film could be formed satisfactorily.

In the above embodiment, the inside of the heating device is partitioned into two chambers, and the conductor and the oxidizing reaction gas are brought into contact with each other by introducing gas from one chamber to the other. and a heating device for heating the conductor are provided separately, and the heating start temperature of both and the contact condition of the conductor and the reaction gas are set to the predetermined temperature conditions according to the present invention, thereby preventing the formation of copper hydroxide. can do.

[Effects of the Invention] As explained above, according to the method for manufacturing a wire insulated conductor of the present invention, when forming an oxide film on the surface of a copper wire by heating the conductor in an oxidizing atmosphere, The oxidation treatment is performed by setting specific heating conditions and contact conditions between the conductor and the oxidizing reaction gas.

As a result, regardless of the size of the conductor, even in the case of a large conductor, it is possible to prevent the generation of unnecessary copper hydroxide and to form a good oxide film, thereby improving reliability. .

Claims (1)

[Claims] (1) A copper stranded wire conductor made of copper wires twisted together is heated, and when the heating rate of the copper stranded wire conductor becomes steady, the copper stranded wire conductor is heated. A method for producing an insulated copper wire conductor, comprising: forming an oxide film on the surface of the copper wire conductor by bringing it into contact with an oxidizing reaction gas at a temperature higher than that temperature.