JPS583325B2 - Surface treatment method for Al or Al alloy overhead power transmission lines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface treatment method for preventing audible noise (hereinafter abbreviated as AN) caused by corona discharge of an AI or A1 alloy (hereinafter abbreviated as aluminum) overhead power transmission line.

Generally, aluminum overhead power transmission lines are made by hot-rolling a bar-shaped ingot obtained from molten aluminum to make a rough wire, which is then continuously drawn through multiple dies at room temperature, and then twisted together into a large number of strands. It is built.

In the wire drawing and wire twisting steps, relatively high viscosity water-insoluble lubricating oil is usually used in order to obtain good workability and a defect-free surface.

Therefore, the surface of the stranded wire is hydrophobic due to the presence of an oil film, and when this is used for ultra-high voltage power transmission lines, the water adhering to it during rainfall becomes spherical, and the electric field strength concentrates on the protrusions, creating a corona and generating AN. Moreover, because of its spherical shape, it takes a long time for evaporation to disappear even after the rain has stopped, and AN continues to occur during that time.

To prevent this, methods have been adopted to relatively reduce the electric field strength on the surface of the wire by increasing the outer diameter of the stranded wire or using multiple conductors, but these methods not only result in higher costs, but also have little effect in reducing AN. I was not able to admit.

A method of forming a compound having a hydrophilic hydroxyl group or water of crystallization on the surface of a wire constituting a stranded wire (Japanese Patent Publication No. 36-1
4076), a chemical method such as the method of forming an alumite film (Japanese Patent Publication No. 40-28304), or a method of applying sandplast (Japanese Patent Publication No. 36-14185), a method of applying water conductive tape in a spiral shape on the surface of the stranded wire. Physical methods have been proposed, such as a method of winding the material around the skin (Japanese Patent Publication No. 36-6430), but chemical methods not only require pre-treatment and post-treatment such as washing and drying, but are also difficult to prevent pollution. It is not practical from the viewpoint of treating upper and waste liquids, and physical methods have drawbacks in terms of treatment efficiency and cost.

In view of this, and as a result of various studies, the present invention focuses on the fact that in order to prevent AN, it is sufficient to increase the wettability and spreadability of water droplets attached to the surface of the outermost layer of the stranded wire. This technology has developed a surface treatment method that improves the wettability and spreadability of aluminum overhead power transmission lines.
A caustic soda solution mist chamber and a hot air drying aphrodisiac are provided in tandem, and the strands are sequentially passed through to heat the outer peripheral surface of the strands, and then brought into contact with the mist of the caustic soda solution.
This method imparts hydrophilicity to the outer circumferential surface of the stranded wire by decomposing oil adhering to the outer circumferential surface of the stranded wire and lightly etching the outer circumferential surface of the stranded wire.

That is, as shown in FIGS. 1 and 2, the present invention twists aluminum wire 1 into multiple layers using a wire twisting machine, presses this with a presser 2 to form a twisted wire 3, and twists this into a stranded wire 3 with a guide roll-equipped trapper 4. Winding the wire onto the drum 5 through the wire is similar to the conventional stranding process, but a heating furnace 6, a mist chamberer 7 for caustic soda solution, and a hot air dryer 8 are installed in tandem between the presser 2 and the trapper 4 with guide rolls. The stranded wire 3, which is made by twisting the aluminum wires 1 in multiple layers, is sequentially passed through a stranding machine, and the outermost layer of the stranded wire 3 is heated to 40 to 80°C in a heating furnace 6.
After heating to a temperature of 1.5-5 in the mist chamber γ
% caustic soda solution mist to decompose and remove the oil adhering to the surface of the outermost layer of the stranded wire 3 and lightly etch the surface, which is then dried in a hot air dryer 8 to impart hydrophilicity to the stranded wire 3. It is something to do.

As the heating furnace 6, the outermost layer of the running stranded wire 3 is 40 to 8
Any material may be used as long as it has a heat capacity capable of heating to 0°C.

The mist chamber 7 for the caustic soda solution may be one that is uniformly filled with the mist of the caustic soda solution. For example, as shown in FIG. cover 11
A concave mist reflector 12 is installed inside the tank 10, and a nozzle 13 introduces compressed air from the outside toward the reflector 12, and a siphon 14 rises from the caustic soda solution. A mist of caustic soda solution may be sprayed using a spray consisting of:

The reason why the mist of the caustic soda solution is sprayed toward the reflecting plate 12 is to reduce the pressing force of the mist and make it finer to prevent the mist from penetrating into the inner layer of the stranded wire 3, and to prevent the mist from entering the inner layer of the stranded wire 3. This is to ensure uniform contact with the mist.
Desirably, the diameter of the nozzle 13 is 1 to 1.5 mm, and the air pressure is 0.5 to 1.2 atmospheres.

It is desirable that the mist chamber 7 is completely sealed to prevent leakage of mist and reaction gas, but the sealant at the entrance and exit of the stranded wire 3 is made of a material such as Teflon resin, which has excellent self-lubricating properties, wear resistance, and heat resistance. As shown in the figure, if a forced exhaust device 15 is attached and the gas is discharged after contact neutralization treatment with a weak acid, there is no problem in practice.

In the figure, reference numeral 16 indicates a guide roll.

The contact reaction between the stranded wire and the caustic soda solution mist is a high-temperature reaction because the outermost layer of the stranded wire is heated to 40 to 80° C., and the decomposition reaction of the attached oil and the corrosion reaction of the aluminum are completed on the order of seconds.

However, the reason why the temperature of the outermost layer of the stranded wire is set at 40 to 80°C is that if it is lower than 40°C, not only is there a risk that the mist may penetrate into the inner layer of the stranded wire, but also the time required for the decomposition reaction of the attached oil and the corrosion reaction of the aluminum is required. This is because if the temperature exceeds 80° C., the physical strength of the stranded wire 3 may decrease.

In addition, the caustic soda concentration of the caustic soda solution is 1.5 to 5.
% because if it is less than 1.5%, the decomposition and removal of attached oil will be insufficient, and if it exceeds 5%, corrosion of aluminum will increase more than necessary.

If the stranded wire treated according to the present invention is placed on a power transmission line as is, there is no lubricant on the outer periphery of the stranded wire, so there is a risk of scratches due to friction with a fishing wheel or the like.

Therefore, when installing overhead wires, it is necessary to apply soluble oil containing a surfactant to the outer periphery of the twisted wires.

The required suitability of soluplu oil is that it exhibits a kinematic viscosity of 30 to 130 centistokes at 40°C, is easily soluble in water at room temperature, has a surface tension of 37 dynecm or less at 25°C of a 10% solution, and does not discolor aluminum. Alternatively, commercially available unruple oil may be selected as long as it does not have corrosive properties.

As a general rule, it is preferable to apply soluplu oil in a state that does not contain 10% or more of water in order to maintain the oil film, and it has the effect of significantly reducing the contact angle between the rainwater that comes into contact with the wire surface after contacting the overhead wire, and the treatment of the present invention does not impede the AN prevention effect.

Next, an example of the treatment method of the present invention will be described.

Example 1 Based on the processing method of the present invention shown in FIG.
ACSR wires (steel core Al stranded wires) of 9.4 mm were twisted together and treated under the following conditions, and then a charging test was conducted.

The results are shown in Table 1. Processing conditions Transfer speed of stranded wire 3 m/min Heating temperature of stranded wire 80℃ Concentration of caustic soda solution Temperature of 1.7% caustic soda solution 25℃ Number of spray nozzles arranged
Air pressure of 4 spray nols 0.6kg/
ca (diameter 1.2 mm) 8 seconds contact time with mist of isoda solution Soluble oil Unisolble S (manufactured by Nippon Oil Co., Ltd.) used for overhead wire Example 2 In the same manner as in Example 1, the outer diameter was 20 mm using a stranding machine. .0mm A
CSR wires were twisted together and treated under the following conditions.

A charging test was conducted on this, and the results are shown in Table 2.

Processing conditions Transfer speed of stranded wire 5 mm/mIn Heating temperature of stranded wire 40℃ Concentration of caustic soda solution Temperature of 5% caustic soda solution
20℃ Number of spray nozzles arranged: 2 Air pressure of spray nozzles: 1.2kg/cm
2 (diameter 1.5 mm) Contact time with mist of caustic soda solution for 3 seconds Solupul oil Natalina GC fluid (manufactured by Shell Oil Co., Ltd.) used for overhead wire Example 3 In the same manner as in Example 1, the outer diameter was 25 mm using a stranding machine. 9mm A
CSR wires were twisted together and treated under the following conditions.

A charging test was conducted on this, and the results are shown in Table 3.

Processing conditions Transfer speed of stranded wire 6 m/min Heating temperature of stranded wire 60℃ Concentration of caustic soda solution Temperature of 3% caustic soda solution
Number of 30℃ spray nozzles arranged: 3 Spray nozzles Air pressure of 7 nozzles: 1.0kg/cm2
(Diameter: 1.0 mm) Contact time with mist of caustic soda solution for 6 seconds Soluble Oil Metal Thin N-101 (manufactured by Kyoeisha Yushi Kogyo) used for overhead wires As can be seen from Tables 1 to 3, the treatment of the present invention was applied. All of them have good wettability and spreadability with water, and during ultra-high pressure charging,
Based on the discharge phenomenon caused by electric field concentration at the top of the water droplet, AN noise can be completely prevented.

As described above, the present invention can be easily added to an existing stranded wire production line to improve water wettability and spreadability in a rational and economical manner, and has an industrially significant effect.

[Brief explanation of drawings]

FIG. 1 is an explanatory view showing one embodiment of the method of the present invention, and FIG. 2 is a sectional view of the same mist chamber. 1... Element wire, 2... Presser, 3...
...Twisted wire, 4...Traparser, 5...
...Drum, 6...Heating furnace, 7...
Mist chamber, 8...Hot air dryer.

Claims (1)

[Claims] I During the manufacturing process of AI or AI alloy overhead power transmission lines, a heating furnace, a caustic soda solution mist chamber, and a hot air dryer are provided in tandem between stranded wire processing and drum winding, and the stranded wires are sequentially A method for surface treatment of an AI or AI alloy overhead power transmission line, characterized by imparting hydrophilicity to the outer peripheral surface of the stranded wire by passing the wire through the wire. 2. The AI or AI alloy overhead power transmission line according to claim 1, wherein the outermost layer of the stranded wire is heated to 40 to 80°C in a heating furnace and brought into contact with a mist of a caustic soda solution having a concentration of 15 to 5% in a mist chamber. Surface treatment method.