JPS6345692Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to an overhead power transmission line that can prevent wind noise on overhead power transmission lines and significantly reduce corona noise. 2. Description of the Related Art Conventionally, in order to prevent wind noise from overhead power transmission lines, it is known to separately wind a metal wire in a spiral shape at a predetermined pitch around the outer periphery of an overhead power transmission line. However, although the above-mentioned overhead power transmission line wrapped with metal wire can reduce wind noise, there is a problem in that corona noise is generated during rain. The inventors of the present invention have conducted various research into electric wires that can prevent corona noise even in overhead power transmission lines that prevent wind noise by winding the metal wires described above. We have discovered that corona noise can be significantly reduced by heat-treating the stranded wire conductor, and by applying a hydrophilic treatment to the metal wire wound around the outer periphery of the stranded conductor that has been subjected to the treatment. completed. According to research by the present inventors, in order to prevent corona noise from overhead power transmission lines wound with metal wires, heat treatment of the stranded conductor and hydrophilic treatment of the metal wires wound around the stranded conductor are necessary. Both treatments are essential, and if either treatment is lacking, the corona noise prevention effect will be lost. Hereinafter, the overhead power transmission line of the present invention will be explained with reference to the drawings. Fig. 1 is an explanatory diagram showing one embodiment of the overhead power transmission line of the present invention, in which 1 is a stranded conductor such as steel-cored aluminum stranded wire (ACSR), and at least the outermost layer surface is in an oxidizing atmosphere. Heat treatment has been applied. Reference numeral 2 denotes a metal wire made of aluminum single wire or aluminum stranded wire, which is spirally wound at a predetermined pitch around the outer periphery of the stranded wire conductor 1 which has been subjected to the above heat treatment, and the outer periphery surface of which has been subjected to hydrophilic treatment. It is strained. The above heat treatment in the present invention is a treatment performed in an oxidizing atmosphere such as air, and is
C 3110, JIS C 3108, JIS C 3109 or
This is a heat treatment that does not reduce the mechanical strength required as a conductor for overhead power transmission lines as specified by JEC etc. Specifically, the surface of the stranded wire conductor is exposed to a flame of propane gas in the air for a predetermined treatment time that does not reduce the conductor strength specified by JIS and JEC above, for example, 5
Examples include a method of performing a spray heat treatment at a rate of cm/sec, or a method of passing a stranded conductor through a high temperature (for example, 900° C.) gas furnace in an oxidizing atmosphere. The above heat treatment may be performed after the conductor strands are twisted together to form a stranded conductor, or alternatively, the conductor strands may be heat treated and then twisted to form a stranded conductor. According to research by the inventors of the present invention, if the surface of the outermost layer of the stranded conductor is roughened by sand blasting, etc., and then subjected to the above heat treatment, it can be effective in preventing corona noise as an overhead power transmission line. Improved and desirable. In addition, the hydrophilic treatment applied to the outer peripheral surface of the metal wire 2 in the present invention includes heating the metal wire in an oxidizing atmosphere, immersing it in an acid or alkaline solution, alumite or boeymite treatment, or Examples include a treatment in which one or more powders selected from metals, metal oxides, metal hydroxides, and metal carbonates are adhered to the surface of the metal wire. In particular, those subjected to a heat treatment similar to the above-described heat treatment to the stranded wire conductor in an oxidizing atmosphere such as air are preferred from the viewpoint of corona noise prevention effect. Next, the corona noise prevention effect of the overhead power transmission line of the present invention will be explained based on examples. Example: Using a normal wire twisting machine, 7 copper wires with a wire diameter of 3.8 mmφ are
After twisting, 54 aluminum wires having a wire diameter of 3.8 mm were twisted around the outer periphery of the copper stranded wire to produce an ACSR of 610 mm ² . Next, the above ACSR was subjected to the treatments shown in Table 1. Further, an aluminum wire having a wire diameter of 7 mmφ was spirally wound around the ACSR at the same pitch as the twisting pitch of the ACSR. The treatment of the outer peripheral surface of the wound aluminum wire is as shown in Table 1.

[Table] The above sample was taken 2.7 m long and was installed in a straight line in the center of a wire mesh cage with an outer diameter of 1 m. A shower was applied to the sample from above the wire mesh cage for 5 minutes at a precipitation rate of 100 mm/h, and each sample was 8, 10, 12, 1
A potential of 4 KV/cm was applied. After the rain stopped, 1
The corona noise of each sample was measured for each potential at 1 minute, 1 minute and 30 seconds, and 2 minutes. Figure 2 shows the average values of corona noise after 1 minute, 1 minute and 30 seconds, and 2 minutes after the precipitation stopped. As is clear from FIG. 2, the corona noise level of the overhead power transmission line of the present invention is significantly lower than that of the overhead power transmission line (Comparative Example 1) and Comparative Examples 2 and 3 in which a normal metal wire is wound. Further, in the overhead power transmission line of the present invention, Example 2 in which the surface of the stranded wire conductor is sandblasted has a better corona noise prevention effect than Example 1 in which sandblasting is not performed.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an embodiment of the overhead power transmission line of the present invention, in which 1 is a stranded conductor whose outermost layer surface has been heat-treated in an oxidizing atmosphere, 2 is a stranded conductor wound around the stranded conductor, It is a metal wire whose outer peripheral surface has been treated to make it hydrophilic. FIG. 2 is a diagram showing the corona noise prevention effect of the overhead power transmission line of the present invention.

Claims (1)

[Scope of utility model registration request] An aerial structure characterized in that the surface of at least the outermost layer of a stranded wire conductor is heat-treated in an oxidizing atmosphere, and a metal wire subjected to a hydrophilic treatment is wound in a spiral shape around the outer periphery of the stranded wire conductor. power line.