JPH02192613A - Low corona noise wire - Google Patents

Abstract

PURPOSE:To obtain a low corona noise wire in which sufficient hydrophilic property can be maintained for a long period without giving bad effect such as corrosion to a steel core by forming a hydrophilic film that is composed of an aluminum complex, on the surface of an outermost strand that is composed of aluminum or of aluminum alloy. CONSTITUTION:After degreasing and cleaning a steel core aluminum strand whose outermost layer is composed of aluminum or of aluminum alloy, using a complex agent by which a complex is formed with aluminum at the temperature higher than the room temperature, a complex film of a aluminum is formed on the surface of the aluminum strand. By forming the film of the aluminum complex on the surface of the outermost strand, the eventually has a great hydrophilic property, so that the formation of large water drop during rainfall is eliminated for the starting voltage of corona to be increased largely, and the generation of corona noise in hyper voltage transmission of electrical energy, such as is UHV transmission can be decreased to a large extent. Decrease in corona noise of the wire can surely be achieved in a easy process, and it is possible to maintain the effect for a long period without giving bad effect to the steel core.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a low-corona noise electric wire that can significantly reduce corona noise in ultra-high voltage power transmission lines.

[Prior technology] Seishin aluminum stranded wires, which are used as ultra-high voltage overhead power transmission lines, require lubricating oil in the wire drawing and stranding processes, and also to improve the slippage of tools during overhead line work. Lubricating oil is used to do this, and the lubricating oil remains in the form of an oil film on the surface of the wire after it has been installed.

Therefore, when it rains, the adhering raindrops form spherical water droplets due to the water in the oil film and continue to adhere to the wire surface for a long time without falling. When these water droplets are formed on an ultra-high voltage power transmission line, the potential gradient at the tip increases, causing corona discharge. Such a corona discharge is
The noise has become a problem because it not only causes noise intrusion into nearby radio wave facilities, but also generates hum and random sounds.

The large water droplets mentioned above are likely to form on overhead power lines because:
The oil film remaining on the surface of the wire is still new, and as the wire ages, the oil film gradually deteriorates and decomposes and no longer exhibits the above-mentioned water resistance.In addition, dust adheres to the surface of the wire and corrosion products of aluminum occur. As a result, the surface of the wire gradually becomes hydrophilic, causing a so-called aging effect. In this aging state, even if it rains, raindrops will spread over the surface of the wire.
Since the water does not directly flow down the surface of the wire and form the large water droplets described above, the corona discharge described above is less likely to occur.

For this reason, we focused on this aging effect and treated the surface of newly installed electric wires in advance so that the new electric wires had the same hydrophilicity as those that had undergone the aging described above, to prevent water droplets from forming on the surface. Low corona noise electric wires have been proposed.

Specifically, wires whose surface has been artificially aged with NaOH, wires whose surface has been coated with an ether-type nonionic surfactant, and wires whose surface has been treated with hydrophilic resin. Various proposals have been made, including one in which the surface is subjected to hydroxide treatment to form a hydrated alumina layer.

[Problems to be Solved by the Invention] The already proposed low-corona noise electric wires described above each have the following problems, and it is difficult to say that they are still sufficient.

For those treated with NaOH, strong alkali NaOH
This may accelerate corrosion of the steel core portion of the steel-core aluminum stranded wire. Surfactant treatment, hydroxylation treatment, etc. do not have sufficient lasting effects on hydrophilicity, and only short-term effects can be expected.When treating with hydrophilic resins, the hydrophilic effect of the resin itself is sufficient. The problem is that there is no.

The purpose of the present invention is to solve the problems of the conventional technology as described above, and to provide a new low-corona noise electric wire that maintains sufficient hydrophilicity for a long period of time without causing any adverse effects such as corrosion on the steel core. This is what I am trying to do.

[Means for Solving the Problems] The present invention is a stranded wire made of aluminum or an aluminum alloy, in which a hydrophilic film made of an aluminum complex is formed on the surface of the outermost layer strand, and further, in the complex formation treatment, Finally, a silicate aqueous solution treatment is performed to form a silicate film.

[Working The complexing agent that forms the core aluminum complex has severe corrosive properties like NaOH, and there is no risk of adversely affecting the internal steel core, and the complex formed is stable in terms of weather resistance. It has high hydrophilicity and can maintain sufficient hydrophilicity for a long period of time.

Furthermore, if such a complex treatment is performed and then treated with a silicate aqueous solution, a silicate film is further formed on the complex treatment film, further improving water wettability. .

[Example] The present invention will be described below with reference to Examples.

In the present invention, after degreasing and cleaning a steel-core aluminum stranded wire (the same applies even if it is an all-aluminum alloy stranded wire) whose outermost layer is made of aluminum or aluminum alloy, a complex with aluminum is formed at a temperature higher than room temperature. Using a complexing agent such as acetylacetone, tartaric acid, citric acid, triethanolamine, sulfosalicylic acid, etc., the mixture is immersed in an aqueous solution of about 0.1 to 30% for about 30 seconds to 120 minutes,
A drying step is provided as necessary to form an aluminum complex film on the surface of the aluminum wire.

By forming a film of aluminum complex on the surface of the outermost wire in this way, the film becomes highly hydrophilic, eliminating the formation of large water droplets during rain and increasing the corona initiation voltage. Even in extremely high voltage power transmission such as UHV power transmission, the generation of corona noise can be greatly reduced.

Although it is possible to greatly improve hydrophilicity by forming a film of the above-mentioned complex, the inventors further improved the surface by performing a silicate treatment on the complex film. Coating the film with the complex film and 11DF once [DIff
[li! mTff+cmT discipline sweet 1111: Not only can the long-term wettability be made even better by using it to improve the long-term wettability, but also the effect can be maintained for a longer period of time. I discovered that.

In addition, in either case of forming only a complex film or a double film with silicate, the wire surface is roughened in advance to a roughness of about 100 to 300 μm using a sandblasting device, etc., and then subjected to the above-described complex film forming treatment. Alternatively, if a silicate film formation treatment is further performed, the hydrophilicity of the wire surface can be further improved by synergizing with the physical water retention effect of the fine irregularities on the wire surface, which can be a major contributing factor in reducing corona noise. We can expect improvement.

Example 1 810/2Sl core aluminum stranded wire was subjected to the respective hydrophilic treatments shown in Table 1, and then its hydrophilicity, steel core corrosivity, and corona noise level were measured.

2"t'r3↑W"fIe'Iht ff1rYIn
醗TiTr ';'; Process 30 seconds with "i" contract 1,
WLi to be R Uni 1008m? After degreasing -Ni by dipping in trichloride for 30 seconds, it was heated to 40°C.
2')'6 The wire was immersed in a seven-ton aqueous solution for 1 minute and coated with a water-soluble lubricant to obtain a low-corona noise electric wire according to the present invention.

Regarding hydrophilicity as an evaluation item, the contact angle was measured using a wet contact angle meter, and the corrosiveness of the steel core was determined based on the appearance of dismantled electric wires that had been exposed outdoors for three months after each treatment. In addition, regarding the corona noise level, we set the rainfall amount to 2On+n/hr for each sample.
Water was injected for 1 minute, and the corona noise level at a maximum surface potential gradient of 15 kv/an was measured about 2 minutes after the water injection was stopped.

Table 1 shows the results.

The additional benefit of being able to achieve Table 1 can also be expected.

As can be seen from the table, the conventional example treated with NaOH has a large corona noise reduction effect, but because it is strongly alkaline, the steel core corrodes significantly. Moreover, in the case of the hydroxylated material, the duration of hydrophilicity is short, and the corona noise reduction effect is also insufficient.

Comparison with these conventional examples clearly shows that the electric wire according to the present invention does not cause corrosion of the steel core and exhibits a sufficient corona noise prevention effect. As well,
As mentioned above, the processing time is short and the equipment is simple, so the effect of reducing the number of man-hours and the simplification of the equipment make it easier to use.Example 2: The same 8LOrm2 steel core aluminum stranded wire as above was heated in a tri-cleaner for 30 seconds. After thoroughly degreasing by immersion, the wire was soaked in 2% acetylacetone water (IBM) at 40°C for 1 minute to form a complex film on the surface of the outermost layer of the stranded wire with good water wettability (contact angle: 10” to 30°). Furthermore, a specific gravity of 1.10 is applied on this treated film.
A diluted sodium silicate aqueous solution (30°C) was spray applied, and then heated and dried at about 220°C for 30 seconds to form a 2 μm thick sodium silicate film with a contact angle of 20°C or less.

Implementation S3 After thoroughly degreasing the same <81011II 2gA core aluminum stranded wire by immersing it in Triclean for about 30 seconds, its outermost surface was treated with a sandblasting device for 30 seconds to achieve Ra=
The surface was roughened to 100 μm.

This twisted wire was immersed in a 0.5-layer tartaric acid aqueous solution at 40°C,
Good water wettability on the outermost layer surface (contact angle 10° to 30°)
A complex film is formed, and a specific gravity of 1.1 is further applied on this treated film.
A sodium silicate aqueous solution (30° C.) diluted to 0.0° C. was spray-coated and then heated and dried at about 220° C. for 30 seconds to form a 2 μm thick sodium silicate film with a contact angle of 20° or less.

The figure is a diagram plotting the changes in water wettability over time when the above-mentioned Examples 2 and 3 according to the present invention, a conventional low-corona noise electric wire with a surfactant film formed on the surface, and normal Ti were exposed outdoors. It is.

Normal wires exhibited water repellency for about six months after they were new, and water droplets formed on the wire surface after rainfall, resulting in high corona noise levels. After about 6 months, the water wettability improved due to corrosion products and deposits on the wire surface, and the corona noise decreased.

Further, although the conventional low corona noise electric wire has fairly good initial water wettability, it lacks durability and loses its effectiveness within 2 to 3 months after exposure. Therefore, due to the interaction with the aging of the wire surface, the contact angle reaches a maximum value around 4 months as shown in the figure, and then reaches equilibrium at around 40°. As a result, +I! The corona sound level generated does not decrease much for 2 to 6 months after dew, and is insufficient as a countermeasure for low corona noise.

In contrast, in the examples according to the present invention, good water wettability is maintained for a long period of time by providing two hydrophilic layers.

Although the top layer of sodium silicate film disappears within several months after exposure, the underlying complex film takes over good water wettability and maintains its effectiveness for 6 to 18 months overall, so the wire surface does not age. While waiting for hydrophilicity to occur, a sufficient corona noise reduction effect can be maintained.

[Effects of the Invention] As described above, according to the low corona noise electric wire according to the present invention,
It has great industrial significance, as it is possible to reliably reduce corona noise in electric wires through simple processing, and the effect can be sustained for a long period of time, with no adverse effects on the steel core. .

[Brief explanation of the drawing]

The figure is a diagram showing the long-term exposure test results.

Claims (4)

[Claims] (1) A low-corona noise electric wire comprising a stranded wire in which the outermost layer of wire is made of aluminum or an aluminum alloy, and a hydrophilic film made of an aluminum complex is formed on the surface of the wire. (2) Claim 1 in which a hydrophilic film made of an aluminum complex is formed on the surface of the outermost layer strand in a roughened state.
Low corona noise electric wire as described. (3) A low-corona noise electric wire comprising a stranded wire in which the outermost layer of wire is made of aluminum or an aluminum alloy, a film made of a complex with aluminum is formed on the surface of the wire, and a silicate film is formed thereon. (4) The low corona noise according to claim 3, wherein the surface of the outermost wire is roughened, a film made of a complex with aluminum is formed on the surface of the wire, and a silicate film is formed thereon. Electrical wire.