JPH01177817A - Snow spiral material for transmission line - Google Patents

Abstract

PURPOSE:To increase the quantity of heat per unit weight by replacing the center of a linear magnetic unit with nonmagnetic metal or alloy having smaller density than that of the unit. CONSTITUTION:Aluminum is employed as a core material 1, its surface is covered with a magnetic material 2 having a composition of 36wt.% of Ni, 2.0wt.% of Cr, 0.8wt.% of Si and the residue of Fe, further covered on its outermost layer 3 with aluminum to form a snow spiral material. Thus, the quantity of heat per unit weight can be increased by approx. 20%.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a snow spiral material for power transmission lines that is wrapped around electric wires to prevent freezing of overhead power transmission and distribution lines.

(Conventional technology) In cold regions such as northern Japan and the inner parts of Japan, ice and snow adhere to overhead power lines during the winter, and this grows into large clumps, leading to an increase in the weight of the wires in the span and an increase in wind pressure loads. This often causes accidents such as broken power lines and the collapse of steel towers. Furthermore, if the ice and snow that adheres to the ground fall in the form of blocks, it is not only dangerous for people passing under the overhead wires, but can also cause damage to crops in farmland, causing major social problems. There is a demand for a solution to this problem. Conventionally known measures to prevent the formation of ice and snow include the following.

(1) Snow melts using overload energization heat generation.

(2) Attaching a snow-preventing ring or preventing twisting of the electric wire itself allows snow to grow in one direction and fall off due to gravity.

However, regarding (1), there is a problem in that it cannot be implemented freely due to restrictions in power system operation. Regarding (2), it cannot be said to be a sufficient measure as it may not be effective depending on the type of ice and snow. On the other hand,
In Special Publication No. 42-1.3893, zero
A method has been proposed in which a magnetic material having a Curie point within the range of ~20° C. is attached, and an alternating magnetic field is used to melt snow by utilizing heat generated by eddy current loss generated within the magnetic material. this is(
This is a practical method that does not cause problems in power operation like in 1), but the magnetic material used here is Cr9~
14-tχ, Ni34-38wtχ, SiO, 5-1.
It is an alloy consisting of 15wtχ and the balance is Fe, and it has poor magnetic properties and cannot generate effective heat, so it has not been put into practical use.

Therefore, we have previously developed Ni32~52wtχ, Cr9wt% or less, 512w as shown in Japanese Patent Application Laid-Open No. 5B-22321).
We have developed a snow spiral material that can be put to practical use by using a magnetic material with improved magnetic properties consisting of t% or less and the balance being Fe as a core material and coating it with a highly conductive metal.

(Problem to be solved by the invention) However, in recent years, snow spiral materials have come to be required to have even higher calorific value, so even snow spiral materials developed in the future will have practical problems. I found out something.

In other words, if the amount of snow spiral material installed per unit length of electric wire is increased in order to generate high heat generation, the weight of the wire in the span will increase, which will exceed the design strength of the tower, making it difficult to achieve high heat generation. However, it was found that there was a problem in that the cost increased because it was an expensive alloy.

The present invention has been made in view of these problems, and it is an object of the present invention to provide an inexpensive snow spiral material that can obtain higher heat generation effects without increasing the weight per unit length of the wire rod.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present inventors have conducted intensive research and found that the magnetic flux that contributes to heat generation does not penetrate much into the inside of the linear magnetic material, and mainly Focusing on the distribution in the surface layer of the wire, the central part of the linear magnetic material is replaced with a non-magnetic metal or alloy with a lower density than the magnetic material, thereby creating a linear magnetic material with a high magnetic flux density that is effective for heat generation. It has been discovered that by creating a structure that effectively utilizes only the surface layer of the snow, it is possible to reduce the amount of expensive magnetic material used, increase the amount of heat generated per unit weight, and obtain a greater snow melting effect.

(Function) That is, the snow spiral material according to the present invention has a three-layer structure, in which metals such as Affi, Mg, or alloys thereof, which have a lower density than ferromagnetic materials, are arranged in the center of the wire, and the outer layer A ferromagnetic layer is provided on the surface of the magnet, and the outermost layer is coated with a highly conductive metal or an alloy thereof.

Here, in the center of the wire, I/
! The reason for using metals such as , Mg, and their alloys is not only to reduce the weight per unit length of the wire rod, but also to reduce the weight per unit length of the wire rod.
This is because the layered wire rod has excellent drawability, uniformity of deformation of each layer, and adhesion between metals of different structures, similar to the conventional 2N snow spiral material. Therefore, when installing the device on electric wires, the same construction method as before can be used as is. In addition, as a magnetic material provided on the core material surface of Aff, Mg, and their alloys, Japanese Patent Application Laid-Open No. 58-22321)
, Fe-Ni-Cr-St alloys and Ni 1.
5~15wtχ, Si0.2~2wtχ, Mn0.3~
An alloy with excellent magnetic properties, such as an alloy consisting of 3wtχ and the balance Fe, is mainly used.

However, in order to effectively utilize only the surface layer of the linear magnetic material with high magnetic flux density, the magnetic wire according to the present invention uses a metal such as Af, Mg, or an alloy thereof, which has a lower density than the magnetic material, as a core material. This surface is coated with a ferromagnetic material,
Since it has an increased calorific value per unit weight, it can be used even with magnetic materials whose magnetic properties are somewhat inferior. In addition, as the highly conductive metal or alloy to be coated on the outer surface of the wire rod obtained by coating the surface of the core material such as Aj2 with a ferromagnetic material, metals such as Mn2゜Cu, Zn, etc. and alloys thereof are mainly used. used for.

This is done to prevent electrochemical corrosion between the wire and the magnetic wire when the magnetic wire is wound around the wire, and to ensure that the metal surface is the same as the wire surface. This is because eddy current increases and heat generation due to eddy current loss increases. Furthermore, by compositing in this way, the magnetic material becomes less susceptible to processing strain during the wire drawing process, and a better heat generation effect can be obtained. In addition, if this composite magnetic wire is drawn to the desired final wire diameter and then subjected to strain relief treatment by forced rolling, etc., it will become a magnetic wire with even better magnetic properties, resulting in even better snow melting. You can obtain effective snow spiral material.

Next, examples of the present invention will be described.

(Example) A2 is used as a core material, and Ni 36wtX, C
A snow spiral material was produced according to the present invention by coating a magnetic material with a composition consisting of r2, Owtχ, Si0.8wtχ, and the balance being Fe, and further coating Al as the outermost layer.

This cross-sectional structure is shown in FIG. On the other hand, as a comparative example, we measured the calorific value of a snow spiral material with a cross-sectional structure as shown in Figure 2, using the same magnetic material as the core and coating the surface with l, and Table 1 shows the calorific value per unit length and unit weight. The results shown are obtained. As is clear from these results, A with low specific gravity
The snow spiral material according to the present invention has I as a core material, its surface is coated with a Ni-Cr-5i-Fe magnetic alloy, and the outermost layer is coated with Al.
3i - Fe-based magnetic alloy is used as the core material and Alt is applied to the surface of this core material.
Although the weight per unit weight is reduced by 34% compared to the snow spiral material of the comparative example coated with It shows that the calorific value increases by about 20% compared to the comparative example.

Table 1 (Effects of the Invention) As explained above, the snow spiral material for snow melting of the present invention has a core material of a metal such as AN, Mg, etc. or an alloy thereof, which has a small density, and a ferromagnetic coating layer on the surface of the core material. Furthermore, the outermost layer is coated with a highly conductive metal or an alloy thereof, and the structure is such that the surface layer of the linear magnetic material with high magnetic flux density, which has a large heat generation effect in an alternating magnetic field, can be effectively utilized. Because it is a material, the calorific value per unit weight is high (therefore, a larger calorific value can be obtained without increasing the weight of the span, and the amount of expensive magnetic material used can be reduced, reducing costs. You can get the desired effect.

Also, since the surface of the wire is coated with the same highly conductive metal or alloy as the wire surface, there is no problem of electrochemical corrosion and it can be used stably for a long time.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a snow spiral material according to an example of the present invention, and FIG. 2 is a sectional view of a snow spiral material of a comparative example. 1... Core material, <, i), 2-... Ferromagnetic material (Ni-
Cr-5i-Fe alloy, 3... Highly conductive metal (7
N).

Claims (1)

[Claims] A core material (1) made of a non-magnetic metal, a ferromagnetic coating layer (2) on it, and a highly conductive metal coating layer (3) on it.
) as the non-magnetic metal (1) constituting the core material,
A snow spiral material for power transmission lines, characterized in that a metal having a lower density than the metal constituting the ferromagnetic coating layer (2) is used.