JPS6353649B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an aluminum power transmission line (hereinafter abbreviated as aluminum power transmission line) that generates less audible noise due to corona discharge. Conventionally, ultra-high-voltage aluminum power transmission lines that connect steel towers are coated with oil during the manufacturing and installation processes. If there is oil on the surface of the aluminum power line, especially when the aluminum power line is connected to an overhead line, it may be exposed to uneven water such as water droplets adhering to the surface during rain or immediately after the rain. The wet condition caused a very loud audible noise due to electrical corona discharge on the surface. Therefore, in the past, after the power transmission line was installed, the oil on the power line was wiped off with a cloth to prevent corona discharge and reduce audible noise.
Simply removing oils had little effect. In addition, wiping off the overhead wires after contacting the wires is extremely difficult because the work is done high up in the air. To solve this problem, conventional systems have been designed to ensure that even if rainwater adheres to the surface of the power transmission line during or after rain, the water droplets will quickly disappear and the surface will be evenly wetted. For example,
Sandblasting is applied to the surface of the wires that make up power transmission lines, and water droplets that adhere to the wires during rain are dispersed, thereby preventing large water droplets from adhering and improving water drainage (Special Publication No. 36-14185) ,
A hydrophilic compound layer containing hydroxyl groups is formed on the surface of the wires that make up the power transmission line, improving water wettability.
Something to prevent the formation of water droplets (Special Publication No. 36-14076)
(No. 1), an aluminum power transmission line whose surface is roughened and a hydrophilic film is further formed on the surface (Patent Application No. 1983).
-37303), one in which a protective layer is formed on the hydrophilic film (Japanese Patent Application No. 123505/1983), and one in which a hydrophobic film is formed on the surface of the aluminum power transmission line and the surface is roughened. (Japanese Patent Application No. 150714/1983) etc. have been proposed. These have very good water wettability, allowing water droplets (raindrops) to flow out and drip quickly, and residual water droplets to disappear from the power transmission line surface quickly, effectively preventing the generation of audible noise caused by electrical corona discharge. This is extremely preferable. By the way, during and after rain, rainwater (water droplets) adhering to the aluminum power transmission line travels along the surface of the power transmission line, collects at the lowest part of the power transmission line, and falls as water droplets. In addition, the water droplets that have collected at the bottom of the power transmission line move horizontally to the left and right, and the small water droplets gather and fall as large water droplets. However, since aluminum power transmission lines are formed by twisting together aluminum wires (hereinafter simply referred to as "aluminum wires"), when viewed in cross section, the outermost layer 2 of aluminum power transmission wire 1 is A dent 4 is formed between the aluminum strands 3 and 3 located between the aluminum strands 3 and 3, and this dent 4 obstructs the movement of raindrops that are trying to move downward along the surface of the power transmission line 1. , the outflow and dripping of water droplets is poor, water draining becomes difficult, and more water droplets 5 remain in the recesses 4. Also, when viewed from the front, as shown in Figure 2, it has wavy unevenness 6, and due to this unevenness 6, the power transmission line 1
If the water droplets (raindrops) that travel along the surface of A and gather at the bottom of the power transmission line 1 are large, as shown in A, they move horizontally left and right, collect, and fall as large water droplets.
If it is as small as B, movement in the horizontal direction from side to side is inhibited, resulting in problems such as poor drainage.
This is undesirable because it causes audible noise due to corona discharge. This means that even if the surface of the aluminum power transmission line is roughened and made hydrophilic, the same drawbacks will remain to some extent. In view of the above, it is an object of the present invention to provide an aluminum power transmission line that solves the above-mentioned drawbacks. It is formed of an aluminum wire having a diameter smaller than that of the aluminum wire located at the base, and at least its surface is made hydrophilic or roughened and made hydrophilic. The present invention will be described in detail below with reference to the embodiment shown in FIG. The figure shows an embodiment according to the present invention, in which a steel wire 12
In a steel-core aluminum stranded wire (hereinafter referred to as ACSR) 11 in which aluminum wires 13 are twisted around a core, the aluminum wires 13a located in the outermost layer 14 constituting the ACSR 11 are located in an inner layer. It is formed of an aluminum wire having a diameter smaller than that of the aluminum wire 13b, and at least its surface is roughened by forming minute irregularities 15, and a hydrophilic film 16 is further formed on the surface as a hydrophilic treatment. The surface roughening treatment may be performed even if the surface of the power transmission line is roughened after forming the power transmission line, or if the surface of the aluminum wire 13a is roughened in advance and then the wire 13a is placed in the outermost layer of the power transmission line. It may be formed as follows. As for the aluminum wire, for example, the aluminum wire 13b of the inner layer has a ratio of 2.0 to 5.0, preferably 3.2 to 5.0, and the aluminum wire 13a of the outermost layer has a ratio of 2.0 to 5.0.
Select from a range of 2.0〓 to 4.8〓, preferably 2.0〓 to 3.2〓. When the aluminum wire 13a located in the outermost layer 14 constituting the aluminum power transmission line 11 is formed of a small diameter aluminum wire, as shown in FIG. The recesses (grooves) 17 between the holes are small and shallow, and the movement of water droplets is less obstructed by the recesses 17, so that the water droplets flow downward and drip quickly, and the water drains easily. If it is small and shallow, the amount of water 18 remaining in each concavity will be small, and as shown in FIG. It also makes it easier to move horizontally from side to side.
It drains water quickly. Moreover, the power transmission line 1
Since the surface of No. 1 is roughened and made hydrophilic, movement of water droplets is further promoted, water droplets flow out and drip more quickly, and the effect is doubled. The surface of the aluminum power transmission line can be made hydrophilic by spraying pressurized steam, boiling water, immersion, anodizing, chromate treatment, MBV, etc.
This is done by forming a hydrophilic film using methods such as chemical conversion treatment. These methods promote the formation of aluminum hydroxides such as boehmite films and anodized films, and also form hydrated chromium oxides at the same time, which also leads to improved corrosion resistance. . The hydrophilic film may be an anodic oxide film or a chromium oxide film. Further, the surface of the aluminum power transmission line is roughened, for example, by sandblasting or shotblasting, or by using a rotating wheel such as a steel wire or steel whirl to roughen the surface of the power transmission line into minute irregularities. This surface roughening requires uniformly forming minute irregularities on the surface of the power transmission line, and the surface roughness is desirably from several microns to several hundred microns, and is usually carried out to a roughness of 10 microns to 200 microns. Furthermore, when roughening the surface, it is especially important to uniformly roughen the entire outer surface without leaving any leaks.In this case, the degree of roughening may vary depending on the size, hardness, aluminum material, etc. Of course, the methods are different. Therefore, in the means for roughening the surface, each condition is appropriately determined so as to obtain the preferable surface as described above. For example, with sandblasting equipment,
If the surface is to be roughened, blasting conditions such as blasting material, blasting pressure, and processing time are selected so as to obtain the above-mentioned preferred roughened surface. When the aluminum power transmission line is roughened and made hydrophilic, either treatment may be performed first, but it is preferable to roughen the surface and then make it hydrophilic. Next, Table 1 shows the measurement results of the corona noise level of the samples of the implementation product according to the present invention and the comparative product.
Measurement results are 30mm/H using a concentric cylindrical corona gauge.
Turn on electricity while injecting water, and 1.
This is the corona noise level for 3 minutes. Sample A ₁ galvanized steel strand 3.2 mm x 7 steel core with 4.8
Nine aluminum wires with a diameter of 4.8mm are twisted together, and a 4.8mm
Aluminum power transmission line (comparison product) made of 15 aluminum wires twisted together, and then 21 4.8mm aluminum wires twisted together as the outermost layer. The outer diameter is 38.4mm. Sample A ₂ An aluminum power transmission line (comparative product) that was prepared by blasting the sample A ₁ with #100 alundum, then placing it in a pressurized container and holding it in steam at 110°C for 5 minutes. Sample A ₃ An aluminum power transmission wire (comparative product) obtained by blasting the sample A ₁ with #100 alundum, immersing it in a 1.0% triethanolamine aqueous solution at 95 to 100°C for 5 minutes, washing with water, and drying. Sample B ₁ galvanized steel strand 3.2 mm x 7 steel core with 4.8
Nine aluminum wires with a diameter of 4.8mm are twisted together, and a 4.8mm
15 aluminum wires are twisted together, and the outermost layer is 3.2
Aluminum power transmission line (implemented product) made of 30 mm aluminum wires twisted together. Outer diameter 35.2mm. Sample B ₂ An aluminum power transmission line (implemented product) in which the above sample B ₁ was blasted with #100 alundum and then placed in a pressurized container and held in steam at 110°C for 5 minutes. Sample B ₃ An aluminum power transmission line (implemented product) obtained by blasting the sample B ₁ with #100 alundum, immersing it in a 1.0% triethanolamine aqueous solution at 95 to 100°C for 5 minutes, washing with water, and drying. Sample C ₁ galvanized steel strand 3.2 mm x 7 steel core with 4.8
Nine aluminum wires with a diameter of 4.8mm are twisted together, and a 4.8mm
15 aluminum wires are twisted together, and on top of that
Aluminum power transmission line (implemented product) made of 40 2.3mm aluminum wires twisted together, and 46 2.3mm aluminum wires twisted together as the outermost layer. The outer diameter is 38mm. Sample C ₂ An aluminum power transmission line (implemented product) that was prepared by blasting the sample C ₁ with #100 alundum, then placing it in a pressurized container and holding it in steam at 110°C for 5 minutes. Sample C ₃ An aluminum power transmission line (implemented product) obtained by blasting the sample C ₁ with #100 alundum, immersing it in a 1.0% triethanolamine aqueous solution at 95 to 100°C for 5 minutes, washing with water, and drying.

【table】

[Table] According to Table 1 above, 12K with a low surface potential gradient
Comparing the noise levels after 1 minute at V/cm and 14KV/cm, the smaller the wire diameter of the outermost layer of samples B ₂ , B ₃ , C _2, and C ₃ , the smaller the value, indicating that water drains quickly. , and 16KV/cm and 16KV/cm with high surface potential gradient.
Sample B ₂・B ₃・C ₂・C ₃ even after 3 minutes of 14KV/cm
The smaller the wire diameter of the outermost layer, the lower the value, indicating that the water drains quickly and the remaining water droplets are small, and the amount of water droplets remaining between the wires is also small. All samples with roughened and hydrophilized power transmission line surfaces showed the greatest effect. As described above, according to the present invention, the water drains quickly and the amount of remaining water droplets is small, making it extremely effective in preventing the generation of audible noise caused by corona discharge.

[Brief explanation of the drawing]

Fig. 1 is a partially omitted cross-sectional view showing a conventional aluminum power transmission line, Fig. 2 is a front view of the same, and Fig. 3 is a partially omitted cross-sectional view showing an aluminum power transmission line whose outermost layer is made of small-diameter aluminum wire. 4 is a front view of the same, and FIG. 5 is a partially omitted sectional view showing an aluminum power transmission line according to the present invention. 11...Steel core aluminum stranded wire (ACSR), 1
2...Steel core, 13...Aluminum wire, 13a...Small diameter aluminum wire located in the outermost layer, 13b...Aluminum wire located in the inner layer, 15...Minute irregularities, 1
6...Hydrophilic film.

Claims (1)

[Claims] 1 At least the aluminum wire located in the outermost layer constituting the aluminum power transmission line is formed of aluminum wire having a diameter smaller than that of the aluminum wire located in the inner layer, and at least the surface thereof is made hydrophilic or roughened and hydrophilic. aluminum power transmission line.