JPH0417209A - Corona noise preventive electric cable and manufacture thereof - Google Patents

Abstract

PURPOSE:To eliminate corona discharge so as to prevent corona noise by forming a hydrophilic porous film on a surface of an element wire or a stranded wire. CONSTITUTION:A hydrophilic porous film 22 is formed on the outside periphery of a single wire 21, at least whose outermost layer part is made of an Mg containing Al alloy, and a stranded wire 1 containing this single wire at least as a part of its element wires constitutes the cable. Formation of such a hydrophilic porous film 22 can be conducted in a batch process or in a process wherein a wire material to be processed is continuously supplied so as to be continuously fed to respective processes. Accordingly, even when a rain drop sticks to the cable it is absorbed by the hydrophilic porous film 22 in the surface thereof to smooth the surface so as to inhibit corona discharge and prevent generation of corona noise.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The invention of this application relates to a corona noise countermeasure electric wire that takes measures to prevent the generation of corona noise in overhead power transmission lines, etc., and a method for manufacturing the same.

[Prior art] Since the surface of electric wires that have just been manufactured is water-based,
Natural rainfall causes bead-shaped water droplets to adhere to electric wires, increasing the potential gradient on the surface of the water droplets, which generates corona. The audible sound emitted directly into the space at this time is corona noise, which includes irregular sounds that can be heard as ``jeezy'' or ``jeezy,'' and pure tones similar to transformer noise that can be heard as ``jeezy.''
The frequency is twice the power supply frequency).

The random sound component is a type of explosive sound that is generated due to the instantaneous release of energy by corona discharge, has a wide frequency band, and is called "random noise."

On the other hand, it is estimated that the pure tone component is generated by ions generated by corona discharge, excited by the commercial frequency electric field around the wire, and further propagated into the air by collision with neutral molecules. The waveform is almost a sine wave, and is called a ``corona hum.''

As a method of preventing such corona noise, that is, a method of preventing corona discharge, the following methods have been adopted or studied so far.

(a) Method for suppressing potential gradient■ Increase the diameter of the conductor. (Increase in size or use multiple conductors.) ■ Use at low voltage until aging progresses.

■ Increase the size of the lower wire of the multi-conductor.

■ Make the wire arrangement closer to the bottom of the multi-conductor.

■ Add one line below the multi-conductor.

■Cover the wire surface with semiconductor or dielectric.

(b) Method of treating the electric wire itself (method of suppressing the generation of water droplets) ■ Perform surface treatment (including artificial aging).

■ Place water-absorbing material inside the wire.

■Wrap thin wire or provide protrusions.

Among the above-mentioned methods, some of the methods (a) - row attachment method and (b) surface treatment method have been put into practical use.

[Problems to be Solved by the Invention] Among them, electric wires that have been prevented from corona noise by surface treatment have the same structure as ordinary electric wires, and the cross-sectional area, outer diameter,
Since specifications such as weight and weight can be made the same,
Advantageously, it can be manufactured without changing the electrical and mechanical properties.

Specific surface treatment methods include coating with a hydrophilic paint, alumite treatment, boehmite treatment, and weak alkaline solution treatment.

However, these treatments have a problem in that the hydrophilic effect is small, or even if the hydrophilicity is large, the effect deteriorates and water droplets are generated if left for about 30 days. Moreover, especially in boehmite treatment, since the electric wire is treated in a steam atmosphere at 100 to 160° C. for a long time, there is also a problem that mechanical properties, particularly tensile strength, deteriorate.

The purpose of the invention according to this application is to solve such conventional problems and to provide a corona noise countermeasure electric wire that has a large hydrophilic effect and can maintain the effect for a long period of time, and a method for manufacturing the same. .

[Means and effects for solving the problem] The corona noise countermeasure electric wire of the invention according to this application has a hydrophilic porous coating formed on the outer periphery of a single wire whose outermost layer is made of an Al alloy containing Mg. It is characterized by being composed of twisted wires containing as at least a part of the strands.

Further, one of the manufacturing methods of the invention according to this application includes the steps of degreasing a single wire made of an Al alloy at least the outermost layer of which contains Mg, and forming a hydrophilic porous film on the outer periphery of the degreased single wire. and a step of twisting the single wire on which the hydrophilic porous film has been formed so that it becomes at least a part of the strand.

Another aspect of the manufacturing method of the invention according to this application is the step of twisting a single wire made of an Al alloy containing Mg at least in the outermost layer so that it becomes at least a part of the strand. , a step of degreasing the stranded wire, and a step of forming a hydrophilic porous film on the outer periphery of the degreased stranded wire.

The single wire made of an Al alloy in which at least the outermost layer portion contains Mg includes an Al alloy wire entirely made of an Al alloy containing Mg, a single wire made of an Al alloy layer in which only the outermost layer portion contains Mg, and the like. Therefore, Al containing Mg around the core wire
It also includes a clad wire formed by fitting or cladding an alloy pipe. In this case, by using a highly conductive conductor as the core wire, the decrease in conductivity can be compensated for.

In the invention according to this application, the Al alloy contains 0.00 Mg.
It is preferable to contain 0001 to 5% by weight.

By containing Mg in an amount of 0.0001% by weight or more, it becomes easy to form a uniform film on the outermost layer made of the Al alloy. For example, when an alkali silicate aqueous solution is used to form a hydrophilic porous film, if the Mg content is less than 0.0001% by weight, reaction with the alkali silicate aqueous solution is unlikely to occur, resulting in an uneven film. Therefore, as the Mg content increases, a film with greater hydrophilic effect can be obtained in a shorter treatment time. However, if the Mg content is too high, problems arise such as a decrease in electrical conductivity and workability. Therefore, the Mg content is preferably 5% by weight or less.

In the case of a clad wire with an Al alloy layer on the outermost layer,
Japanese Industrial Standards (JIS) 1050Al pipe having an Mg content of 5% by weight or less is easily available and can be used.

This Japanese Industrial Standard 1050Al pipe has Mg of 0.
It is an Al alloy containing 0.05% by weight or less and a total of impurities of less than 0.5% by weight.

In the invention according to this application, the hydrophilic porous film preferably contains aluminum oxide and silicon oxide as main components, and contains 70 to 100% by weight of aluminum oxide and 0 to 30% by weight of silicon oxide.

Moreover, the thickness of the hydrophilic porous film is preferably 10 to 100 μm. When the thickness becomes 10 μm or more, the hydrophilic effect becomes large, and when the thickness becomes even thicker, the magnitude of the hydrophilic effect becomes saturated. If the thickness exceeds 100 .mu.m, problems such as a decrease in the area of the conductor will occur, so the thickness is preferably 100 .mu.m or less.

Moreover, the surface roughness of the hydrophilic porous film is preferably about 0.5 to 5 μm in terms of Ra value defined by Japanese Industrial Standards.

In order to form a hydrophilic porous film of 10 μm or more with good adhesion, the outermost layer made of an Al alloy containing Mg must be
It is preferable that it is 5 μm or more.

The hydrophilic porous film can be formed on the surface of the outermost layer made of an Al alloy containing Mg by using, for example, an aqueous alkali silicate solution.

Such a treatment solution includes 20 to 6 SiO2.
It is preferable to use an aqueous alkali silicate solution containing 0 g/l. If it is less than 20g/1, reaction with AI is unlikely to occur.
In addition, even if the content is increased, the reaction will be saturated, so 6
0 g/l or less is sufficient.

The solid or stranded wire to be treated is immersed in this treatment solution for several minutes. The temperature of the treatment solution is preferably 40 to 120°C. If the temperature is lower than 40℃, the reaction becomes slow, and if the temperature is lower than 120℃.
This is because when the temperature becomes higher, there is a problem of softening of the AI.

Regarding the processing time, if the processing time is longer, the processing can be performed even at a lower temperature, but this is not preferable because the production rate will be reduced. Therefore, the treatment time is preferably about 1 to 30 minutes.

The formation of the hydrophilic porous film may be performed on the single wire that constitutes the stranded wire and then processed into the stranded wire, or by treatment on the surface of the stranded wire after the stranded wire processing. You can.

Formation of such a hydrophilic porous film may be performed by batch processing, or may be carried out by continuously feeding the wire to be processed and feeding it to each processing step.

According to this invention, when raindrops adhere to an electric wire in which a hydrophilic porous coating is formed around the outermost layer, the raindrops are absorbed by the hydrophilic porous coating on the surface and smoothed, so that corona discharge does not occur. First, corona noise can be prevented. Further, the hydrophilic porous film according to the invention of this application does not lose its hydrophilic effect even over a long period of time, and can maintain the effect of preventing corona noise.

[Example] FIG. 1 is a sectional view showing an example of the electric wire of the invention of this application. Referring to FIG. 1, in this embodiment, aluminum-covered steel wires 3 are bundled at the center, and the aluminum-covered steel wires 3 are bundled at the center.
An aluminum wire 2 is provided around the wire and stranded to form an aluminum clad steel core aluminum stranded wire 1.

FIG. 2 is a sectional view showing the aluminum wire of the embodiment shown in FIG. As shown in FIG. 2, the aluminum wire 2 is constructed by forming a hydrophilic porous film 22 around an aluminum wire portion 21. As shown in FIG.

FIG. 3 is a sectional view showing the aluminum-covered steel wire of the embodiment shown in FIG. 1. As shown in FIG. 3, the aluminum covered steel wire 3 is
It is constructed by forming a hydrophilic porous coating 33 around an aluminum covered steel wire with an aluminum layer 32 formed around a central steel core 31.

As described above, in the aluminum stranded aluminum wire with an aluminum clad steel core shown in FIG. 1, a hydrophilic porous coating is formed on each of the aluminum wire and the aluminum clad steel wire, and then these are twisted together to form a stranded wire.

FIG. 4 is a sectional view showing another embodiment of the electric wire of the invention of this application. Referring to FIG. 4, in this embodiment, an aluminum wire 44 is arranged around an aluminum covered steel wire 43, and a hydrophilic porous film is formed around an aluminum covered steel core aluminum stranded wire 41 which is stranded. 42 is formed. In this way, the same effect can be obtained even if a hydrophilic porous film is formed around the aluminum stranded wire after the stranding process.

FIG. 5 is a schematic diagram for explaining an example of the manufacturing method of the invention of this application. Wire to be processed 5 which is a bare wire or a twisted wire
0 is wound around the supply section 51, and this processed wire 50
is first supplied to an organic solvent degreasing tank 52 and degreased. Next, the wire 50 to be treated is supplied to an alkali silicate treatment tank 53, where the wire 50 to be treated is immersed in the alkali silicate solution, and the alkali silicate solution adheres to the surface. Next, the wire to be processed 50 is removed from the preliminary cleaning tank 5.
4 for preliminary cleaning, and then further sent to the main cleaning tank 55 for cleaning. The processed wire 50 after cleaning is transferred to a dryer 5.
6 to be dried, a hydrophilic porous film is formed by this drying, and the film is wound up by a winder 57.

As described above, the manufacturing method of the invention of this application is capable of continuous manufacturing by continuously supplying the processed wire to each processing step in addition to batch processing. The invention related to this application will be explained.

Example 1 1050Al according to Japanese Industrial Standards around heat-resistant aluminum alloy wire
The outermost Al alloy layer is 0.6
Forty-five single wires with an outer diameter of 4.5 mm and a thickness of 4 mm were produced. After first degreasing this using Triclean, 8
Alkaline silicate aqueous solution kept at 0°C (30% as Si02)
g/l, 8.5g/l as Li, 70g/l as Na
1) for 5 minutes. Furthermore, after preliminary washing with 40°C hot water for 5 minutes, washing was performed with 80°C hot water for 30 minutes. Finally, it was thoroughly dried with warm air at 70°C.

Observing the surface of the single wire treated as above,
A hydrophilic porous film was formed. The thickness of this film was 20 μm, and the surface roughness was 2 to 3 μm in Ra value specified by Japanese Industrial Standards.

Seven aluminum-covered steel core wires with an outer diameter of 3.2 mm were prepared, and a single wire with a hydrophilic porous film formed around the aluminum-covered steel core wires was placed and twisted to create the structure shown in Table 1. Manufactured aluminum clad steel core aluminum stranded wire.

Example 2 Around the heat-resistant aluminum alloy wire, 1050A of Japanese Industrial Standards
The pipes of I are fitted together to form a clad wire, and the outermost cladding part has a thickness of 0.64 mm and an outer diameter of 4.5 m.
45 lines of m were made.

Also, around the aluminum-covered steel core wire, the Japanese Industrial Standard 1
Seven wires each having an outer diameter of 3.2 mm and having a cladding layer thickness of 0.43 mm were fabricated by fitting 050 Al pipes together as clad wires. Aluminum strands were arranged around this aluminum-clad steel core wire and twisted to produce an aluminum-clad steel core aluminum stranded wire having the structure shown in Table 1.

After degreasing this twisted wire using trichlene, an aqueous alkali silicate solution kept at 80°C (35g/1X as S102)
Contains 8.5g/l as Li and 70g/l as Na)
It was immersed in the water for 5 minutes.

After further pre-washing with warm water at 40℃ for 15 minutes,
It was washed with hot water for 30 minutes, and finally dried with hot air at 70°C.

When the surface of the stranded wire treated as described above was observed, a hydrophilic porous film was formed on the surface. The thickness of this film was 20 μm, and the surface roughness was 2 to 3 μm in Ra value specified by Japanese Industrial Standards.

Example 3 A Japanese Industrial Standard 105OAI pipe was fitted around a heat-resistant aluminum alloy wire to form a clad wire, and the thickness of the clad layer was reduced to 0.
．． Forty-five single wires each having an outer diameter of 4.5 mm and a diameter of 64 mm were produced. In addition, around the aluminum-covered steel core wire, Japanese Industrial Standard 105
Seven wires each having an outer diameter of 3.2 mm and having a cladding layer thickness of 0°43 mm were manufactured by fitting 0 Al pipes as clad wires. Aluminum single wires were arranged around this aluminum clad steel core wire and twisted together to produce aluminum clad steel core aluminum stranded wires having the structure shown in Table 1.

This twisted wire was continuously processed using an apparatus as shown in FIG. The stranded wire was continuously supplied to an organic solvent degreasing tank at a speed of 50 cm/min, and was degreased using trichlene. Subsequently, an aqueous alkali silicate solution kept at 80°C (35 g/l as Si02, 8.5 g/l as Li, 70 g/l as Na) was added.
g/l) was introduced into a treatment tank in which immersion treatment was performed.

Furthermore, after preliminary washing with 40°C hot water, washing was performed with 80°C hot water. Finally, it was dried with hot air at 70°C and continuously wound onto a reel.

When the surface of the stranded wire obtained as described above was observed, a hydrophilic porous film was formed on the surface. The thickness of this film was 20 μm, and the surface thickness was 2 to 3 μm in terms of Ra value specified by Japanese Industrial Standards.

(Left below) Table 1 As a comparative example, a similar stranded wire treated with conventional boehmite,
Untreated stranded wires were prepared, and these and Example 1 were evaluated in terms of (1) corona properties, (2) hydrophilicity, and (2) corrosion resistance.

The corona characteristics are shown in Table 2 by measuring the hum sound level and random sound level when the surface potential slope was 14 kV and 7 cm during light rain.

Corrosion resistance was measured by an alkali dropping test in accordance with Japanese Industrial Standard H8601, and the number of seconds measured is also shown in Table 2.

Table 2 No water droplets were formed even after being left for 00 days or more.

The wettability of the boehmite treatment was very good, and no water droplets were formed on the top, side, or bottom surfaces, but many small water droplets were formed on the sides after being left for 30 days.

Untreated Water droplets were formed on the top, side, and bottom surfaces.

Regarding hydrophilicity, the results were as follows.

Example 1 The wettability was extremely good, and no water droplets were generated on the top, side, and bottom surfaces. Also 1 above and Table 2
As is clear from the results, the electric wire according to the invention of this application has a large parent tree effect and does not cause corona discharge, so that corona noise can be prevented. Moreover, since the hydrophilic effect of the hydrophilic porous coating does not disappear over a long period of time, the effect can be maintained.

Note that when the corona properties, hydrophilicity, and corrosion resistance of Examples 2 and 3 were also measured, the same results as in Example 1 were obtained.

[Effects of the Invention] As explained above, in the corona noise countermeasure electric wire of the invention according to this application, a hydrophilic porous film is formed on the surface of the stranded wire or the stranded wire, and this hydrophilic porous film makes the surface The parent tree effect is enhanced, and water droplets do not form on the surface. Therefore, corona discharge does not occur and corona noise can be prevented. Furthermore, since the hydrophilic effect of the hydrophilic porous film does not disappear over a long period of time, the corona noise prevention effect can be maintained for a long period of time.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the electric wire of the invention of this application. FIG. 2 is a sectional view showing the aluminum wire of the example in FIG. 1. FIG. 3 is a sectional view showing the aluminum-covered steel wire of the embodiment shown in FIG. 1. FIG. 4 is a sectional view showing another embodiment of the electric wire of the invention of this application. FIG. 5 is a schematic diagram for explaining an example of the manufacturing method of the invention of this application. In the figure, 1 is aluminum clad steel core aluminum stranded wire, 2 is aluminum bare wire, 3 is aluminum clad steel wire, 21 is aluminum wire part, 22 is hydrophilic porous coating, 31 is steel core, 32 is aluminum layer, 33 is a hydrophilic porous coating, 41 is an aluminum-covered steel core aluminum stranded wire, 4
2 is a hydrophilic porous coating, 43 is an aluminum covered steel wire, and 44 is an aluminum bare wire.

Claims (7)

[Claims] (1) The wire is composed of a stranded wire in which a hydrophilic porous film is formed around the outer periphery of a single wire whose outermost layer is made of an Al alloy containing Mg, and the single wire is included as at least a part of the wire. Corona noise countermeasure electric wire. (2) The corona noise countermeasure electric wire according to claim 1, wherein the Al alloy contains 0.0001 to 5% by weight of Mg. (3) The hydrophilic porous film contains aluminum oxide and silicon oxide as main components, and the aluminum oxide content is 70 to 10%.
The corona noise countermeasure electric wire according to claim 1, containing 0% by weight and 0 to 30% by weight of silicon oxide. (4) The thickness of the hydrophilic porous film is 10 to 100 μm
, and the surface roughness is Ra specified by Japanese Industrial Standards.
The corona noise countermeasure electric wire according to claim 1, having a value of 0.5 to 5 μm. (5) degreasing a single wire made of an Al alloy at least the outermost layer portion of which contains Mg; forming a hydrophilic porous film on the outer periphery of the degreased single wire; and forming a hydrophilic porous film on the single wire on which the hydrophilic porous film has been formed. and a step of twisting the wire so that the wire becomes at least a part of the wire.
Manufacturing method for corona noise countermeasure electric wire. (6) processing a single wire made of Al containing Mg at least in its outermost layer to form a stranded wire so that at least a portion of the wire becomes a stranded wire; degreasing the stranded wire; and degreasing the stranded wire. 6. The method for manufacturing a corona noise countermeasure electric wire according to claim 5, comprising the step of forming a hydrophilic porous film on the outer periphery of the stranded wire. (7) The step of forming the hydrophilic porous film comprises S
The method for manufacturing a corona noise countermeasure electric wire according to claim 5 or 6, comprising the step of immersing a single wire or a stranded wire in an aqueous alkali silicate solution containing 20 to 60 g/l of iO_2 and maintained at 40 to 120°C. .