JPS59224014A - Method of producing low corona noise aluminum transmission wire - 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 Technical Field C) The present invention relates to a method for manufacturing a thin steel core aluminum stranded wire (hereinafter referred to as AO8l't) for reducing corona noise used in high voltage power transmission lines.

C) Background Art) AO8R has traditionally been used in overhead power transmission lines, and has played an important role in power transportation.

In recent years, due to the need for large-capacity power transmission, the transmission voltage has tended to be increased.
Corona discharge, especially corona noise immediately after rain, becomes a problem.

The cause of this corona noise is that oil adheres to the AO8R during the manufacturing process, and the AO8R is exposed to A, (18) during or immediately after rain.
1'L surface is in a non-uniform water wet state such as water droplets adhering9
．． The protrusions caused by raindrops on the surface of AO81'L increased the surface potential gradient around the raindrops, generating corona discharge, which caused audible noise. The present invention
As a solution, the water wettability (hydrophilicity) of the AO8FL surface
It has been discovered that by improving the water droplets on AO8RO8, it is possible to eliminate corona discharge and prevent the occurrence of corona discharge.

C) Disclosure of the Invention) The present invention was made as a result of various studies on the above-mentioned 408 surface treatment methods that have good surface hydrophilicity.
The purpose is to provide a method for producing AO8R in which the surface of R is subjected to a special surface treatment to improve its hydrophilicity and reduce corona noise.

The present invention is an AO made by twisting aluminum wire around the outer periphery of steel stranded wire.
After roughening the surface of 8R by a method such as sandblasting, the surface is treated with a surface treatment film in water or steam at a high pressure and high temperature of 1 atm at 100°C or higher. This is a method for producing a low-corona noise aluminum power transmission line, which is characterized by producing low-corona noise.

In the present invention, the surface of the aluminum power transmission line is first roughened,
In this method, the entire surface treatment film (boehmite film) is formed by water or steam treatment. Furthermore, the entire surface of the roughened boehmite film is hydrophilic, and an aluminum power transmission line having a surface with good water wettability can be manufactured.

The surface roughening treatment used in the present invention is performed, for example, by sandblasting, shotblasting, or by roughening the surface of the power transmission line to have minute irregularities using a rotating wheel made of steel wire, steel wool, or the like. . This roughening requires uniformly creating minute irregularities on the surface of the power transmission line, and the surface roughness ranges from a few to several 100 microns, preferably around 100 microns, to improve water wettability after the surface treatment film is formed. It is also advantageous in terms of industrial production.

If the surface of AO8R is simply roughened by blasting, etc., raindrops will turn into water beads on the surface of AO8R, and the goal of reducing corona noise due to the same effect as protrusions cannot be achieved. 1 atm, 10
By completely forming the boehmite film in water or steam at a high pressure and temperature of around 0° C. or higher, water droplets spread quickly after deposition and can be wetted uniformly.

Therefore, without forming protrusions, corona discharge can be significantly reduced and corona noise can be reduced.

(Conventional technology) Conventional proposals of this type include, for example, applying sand to the surface of the strands that make up the electric wire. There is a method of preventing the adhesion of large water droplets and improving drainage by dispersing the water droplets adhering to electric wires during rainfall.

However, with this method, a large number of small-diameter water droplets adhere to the surface of the electric wire, and it is still difficult to obtain a droplet that causes corona discharge.

In addition, a method has been proposed for preventing the formation of water droplets by forming a layer of a hydrophilic compound having hydroxyl groups on the surface of the strands constituting the electric wire to improve water wettability. 36-
140761゜However, with this method, the spread of attached water droplets is slow and the spread range is narrow, so the surface is not evenly wetted especially during light rain such as drizzle or at the beginning of rain, and the effect of preventing corona discharge caused by water droplets remains. Got n, no.

In the present invention, the surface of the aluminum power transmission line is first roughened by sandblasting, etc., and then 1 atm 10
It is treated in high pressure, high temperature water or steam at around 0°C or above to form a surface treated skin. Therefore, in the present invention, by roughening the surface of the aluminum power transmission line, oils deposited during the manufacturing process are removed and the surface is roughened. The surface roughened by this process can actively induce capillary action on water droplets. In addition, a boehmite film is formed on this roughened surface by the water or steam treatment described above, and the hydrophilicity of the sides of this skin makes it possible to greatly improve the wettability of water on the surface of the aluminum power transmission line. . In other words, the water wettability of the surface of the aluminum power transmission line is extremely improved due to the synergistic effect of improving the malleability due to the capillary phenomenon between water droplets due to the surface roughening treatment and water penetration due to the hydrophilicity of the boehmite film. Water or steam treatment is at least 1 atm and approximately 100°C.
Preferably, the lower the temperature, the more difficult it becomes to form a boehmite film.On the other hand, at high temperatures and high pressures, a boehmite film can be formed in a short time, which is a great advantage in terms of production.

Next, among the methods of the present invention, boehmite skin IV! ! In order to generate i, for example, as shown in Fig. 1, an aluminum power transmission line 1 is inserted into a pipe having a steam port 3 and a steam outlet 4, and steam is blown into the pipe for treatment. can.

Note that 5.6) is the notching at both ends of the iso 2 to make it airtight.

It is usually preferable to carry out this steam treatment for 30 seconds or more.

Figure W2 shows an example of an aluminum power transmission line 10 manufactured according to the present invention, which is a steel-core aluminum stranded wire (hereinafter referred to as AO8R) 1 in which aluminum wires 13 are twisted around a steel wire 12 as a core.
1, by forming fine irregularities 14 on the surface thereof by sandblasting, for example, to form a stamp surface, and then applying steam treatment thereon, for example, as shown in FIG. 1, to form a boehmite film (At
The aluminum hydroxide (so-called aluminum oxide film) called 203H20) was completely released.

(Example and Comparative Example) Example: After blasting the surface of AO8R with a cross-sectional area of 810 mm with 100 Alundum, steam at approximately 120°C (approximately 2 atm) was sprayed for 30 seconds, 1 minute, and 3 minutes. Boehmite skin lIα
AO8I('(rm) was produced.

Comparative Example AO8R with a cross-sectional area of 810- without any treatment (Comparative Example 1)
And, the surface was simply blasted with ≠100 Alundum (Comparative Example 2), and the surface was directly exposed to steam at about 120°C (about 2 atmospheres) for 30 seconds, 1 minute, and 3 minutes without blasting. Three units of AC were manufactured by each method of the treated one (Comparative Example 3).

The appearance and uniform hydrophilicity of the above Examples and Comparative Examples are evaluated and shown in the following table.

7-8- Furthermore, in a trial based on Example and Comparison M, electricity was applied while water was being poured using a cylindrical corona gauge, and the attenuation of the corona noise level for 3 minutes after water injection was stopped was measured at a potential gradient of # 12.8 kV/
Measured in cm. The results are shown in the graph of FIG. A
In the case of 810dAO8H as manufactured, B is 810 mJ A (ISR), 0 is 810dA O8R, D is 810tdAa S R (7) surface k"100 treated with steam blasting for 3 minutes. This line shows the case of a product in which steam at about 120° C. (about 2 atmospheres) was sprayed for 3 minutes after blasting with alundum.

According to FIG. 3, AO8B manufactured by the method of the present invention
, (indicated by D), the noise level suddenly decreased after water injection stopped and reached approximately 44 dB after 3 minutes, whereas in the comparative example (A
1 B, (indicated by 1), remains at a high noise level of 59 to 63 dB even after 3 minutes, and the decrease in the noise level is extremely small.

(Effects of the Invention) As described above, the method for manufacturing the low corona noise composite stranded wire of the present invention is such that the surface of the stranded wire is subjected to roughening treatment such as blast treatment, and is thus Alternatively, a surface treatment film C boehmite film 1lp)'e is formed by water vapor, so the hydrophilicity of the electric wire surface is improved by the synergistic effect of the roughening of the surface by the blasting process and the hydrophilization and improvement of water wettability by the underwater or steam treatment. It will be a very good thing, so
During rain, the rain tube does not form water droplets on the surface of the wire, and it forms uniformly, so no protrusions are formed, reducing corona discharge, and significantly reducing corona noise immediately after rain.
! jp:? can play.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing an example of a method for forming aluminum hydroxide on the surface of an aluminum power transmission line, Fig. 2 is a cross-sectional view showing an example of the present invention, and Fig. 3 is a graph showing the results of an effectiveness test. It is. 10... Aluminum power transmission line according to the present invention 11... Steel core aluminum stranded wire (AO8R) 12... Copper wire 13... Aluminum wire 14... Minute irregularities
15...Aluminum hydroxide patent Applicant Fujikura Electric Cable Co., Ltd. Agent Patent attorney Mamoru Takeuchi 11- 1st ↓ Figure 2 Figure 3 0 1 2 3
(Continued from page 1) Author: Takanori Hita, Fujikura Electric Cable Co., Ltd. Shimousa Electric Power Testing Laboratory, 311 Nanasawa, Shimousa-cho, Katori-gun, Chiba Prefecture Author: Ken Saito Futaba-cho, Numazu City No. 9-1 Fujikura Electric Cable Co., Ltd. Numazu Factory

Claims (1)

[Claims] (1) After roughening the surface of the core aluminum stranded wire, which is made by twisting aluminum or aluminum alloy wire around the outer circumference of the steel stranded wire, such as sandblasting, the temperature is 1 atm and 100℃ or more. A method for manufacturing a low-corona-noise aluminum power transmission line, which is characterized by generating a surface treatment layer in high-pressure, high-temperature water or steam.