JPH0249311A - Heat emitting wire material and snow melting electric wire using the same - Google Patents

Abstract

PURPOSE:To provide possibility of melting snow with good effectiveness by spirally forming a ridge consisting of conductive metal at the periphery of a core consisting of ferromagnetic substance. CONSTITUTION:A heat emitting wire 1 consists of a consolidatedly formed Al covering 4 having a spiral ridge 3 at the periphery of a core 2 consisting of ferromagnetic substance. When current flows in this heat emitting wire 1, most of it flows in the ridge with good conductivity to produce a strong mag. field in the core 2, and heat is generated by a large iron loss.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat-generating wire used for melting snow on overhead lines, and a snow-melting electric wire using the heat-generating wire.

[Prior art]

Various methods have been studied and implemented to prevent snow from accumulating on overhead power transmission lines. Typical examples include installing anti-snow rings to prevent snow from forming on electric wires, and wrapping fluororesin (Teflon) tape around electric wires to remove thick snow. There are ways to do this, etc.

These are physical methods to prevent snow accumulation, but
In addition, in places where the environmental conditions under transmission lines are severe, even the slightest lightning strike may not be tolerated, and in such cases it is necessary to find some way to melt away the war clouds or snow on the lines. Several methods for this purpose have been proposed and implemented.

For example, a method is to wrap a low-Kyrie point wire around a 'TIl wire and make use of the magnetic field generated by the wire's 1i current to generate heat at low temperatures to melt snow. A current transformer (CT
) is used as a t source to flow current and melt snow using Joule heat.

〔assignment〕

Methods using anti-snow rings and fluororesin tape do not provide sufficient protection against lightning strikes (and cannot be applied to locations under power lines with severe environmental conditions.

Furthermore, since the method of winding low-Kyrie point wire utilizes the magnetic field generated by the current in the wire, the snow melting effect will not be effective unless a large current flows through the wire.

Normally, snow accretion occurs at night when the load on power transmission lines is low, so in order to obtain sufficient snow melting effect even when the transmission current is low, low-Kyrie dot wire should be wrapped almost tightly around the outer periphery of the wire. There is a need.

However, if this is done, the load on tm will increase, causing problems such as a significant increase in sag and an excessive load being applied to the steel tower.

Also, insulation 3. The method of winding a hot wire has problems such as high cost because it requires CT, and a limited lifespan due to deterioration of the insulator.

[Means for solving problem 1 and its operation] The present invention overcomes the problems of the prior art as described above and provides a new heat generating wire material, the structure of which is a core wire made of ferromagnetic material. It is characterized by a spiral protrusion made of conductive metal formed on the outer periphery.

When an alternating current is passed through such a heating wire,! Since 1tiJ mainly flows spirally along the protrusions with good conductivity, an alternating magnetic field is effectively applied to the core wire made of ferromagnetic material, and heat is generated. As the core wire made of a ferromagnetic material, an iron wire, an A-wire, a low-Kyrie wire, etc. are used, and as the conductive metal, aluminum or copper is used.

The present invention also provides a snow-melting electric wire using the heat-generating wire as described above, and the structure thereof is such that the heat-generating wire as described above is twisted as a bare wire on the outermost layer of a stranded conductor, or It is characterized by being spirally wound around the outer circumference of the conductor.

By arranging the heating wires in this way, a portion of the current flowing through the stranded wire conductor will flow through the heating wires, causing the heating wires to generate heat and melt the snow.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Figure 1 fat (bl indicates an embodiment of the heat generating wire according to the present invention. This heat generating wire 1 has a core wire 2 made of a ferromagnetic material.
An aluminum coating 4 having a spiral protrusion 3 is integrally formed on the outer periphery of the holder.

The heating wire 1 having such a structure is produced by extruding and covering the outer periphery of the core wire 2 with an aluminum 1 covering 4 having protrusions 3 by a continuous extrusion coating method such as the conform method, and then winding the extruded composite wire while twisting. It can be easily manufactured by winding it up and then rotating the winding side or the supply side to give a twist when rewinding.

Although one protrusion 3 may be used, it is more effective to form a plurality of protrusions. Further, the helical pinch of the protrusion 3 is preferably made as small as possible in order to generate a stronger magnetic field.

When current flows through the heat-generating wire 1 as described above, most of it flows through the highly conductive protrusions 3, and since these protrusions 3 are spiral-shaped, it is as if a coil is wound around an iron core. The same state occurs, and the flowing current generates a strong magnetic field in the ferromagnetic core wire 2, causing large iron loss and effectively generating heat.

FIG. 2 shows an embodiment of the snow-melting electric wire according to the present invention, where 1 is a heating wire as described above, 6 is a W4 wire, and 7 is an aluminum wire. In other words, this snow melting electric wire 5 has an aluminum wire 7 and a heating wire 1 in the outermost layer of a steel core aluminum stranded wire.
It is twisted together every other book. Since the snow-melting wire melts snow attached to the surface of the wire, it is effective to twist the heating wire 1 in the outermost layer. The number of heating wires 1 may be determined in relation to the load current.

Note that if a low-Kyrie point material is used as the ferromagnetic core wire of the heating wire l, power loss at temperatures where snow does not form can be reduced. A low-Kyrie point material is a material that loses its ferromagnetic properties above a certain temperature (for example, a temperature slightly higher than 0°C).
FeNi-Cr-5i alloys and the like are known.

FIG. 3 shows another embodiment of the snow melting electric wire according to the present invention. This snow melting IT line 8 is made of steel core aluminum r! ! , the heating wire 1 as described above is wound spirally around the outer periphery of the wire 9. In this example, the electric wires that have already been installed are passed through to form a snow-melting structure.The drawing shows an example in which one heating wire 1 is wound, but the number of heating wires 1 and the number of windings are different. Habi・
The notch may be determined depending on the snow melting target and the load current flowing through the steel-core aluminum strand 9.

The heating wire 1 can be made long and wrapped around the electric wire using a machine, or it can be made into a length suitable for handling like Armor Rond, and it can be formed in advance into a spiral shape according to the diameter of the electric wire and then wrapped. You can do it like this.

Comparing the snow-melting electric wire in Figure 3 with the electric wire wrapped with conventional low-Kyrie dot wire, it is found that both are the same in that the wrapped wire generates heat due to the magnetic field created by the current flowing through the wire, but Figure 3 In addition, in the snow melting electric wire, the current branched to the heating wire l flows in a spiral shape along the protrusion,
This generates a magnetic field and the ferromagnetic core wire generates heat, which is another principle of heat generation. Therefore, the amount of heat generated is much higher than that of conventional models, and snow melting can be performed effectively.

〔Effect of the invention〕

As explained above, in the heat-generating wire according to the present invention, the current flows spirally around the +Im gonadal core, so the ferromagnetic core is efficiently heated by the magnetic field generated by the current, and a large Calorific value can be obtained. Moreover, the snow melting f-line using such a heat generating wire can efficiently melt snow since the heat generating wire has a large calorific value.

[Brief explanation of the drawing]

Figure 1 (alfbl is a sectional view and side view showing one embodiment of the heat generating wire according to the present invention, Figure 2 is a sectional view showing one embodiment of the snow melting electric wire according to the present invention, Figure 3 (δi(' b+ is a sectional view showing another example. 2: ferromagnetic core wire, 3: protrusion, 4: aluminum coating, 5: snow melting electric wire, 6: steel wire, 7: aluminum collar. , 8: Snow melting electric wire, 9: Steel core aluminum P, wire.

Claims (1)

[Scope of Claims] 1. A heating wire characterized by having a core wire made of a ferromagnetic material and a protrusion made of a conductive metal formed in a spiral shape on the outer periphery of the core wire. 2. A snow-melting electric wire, characterized in that the heat-generating wire according to claim 1 is twisted as strands on the outermost layer of a stranded conductor, or wound spirally around the outer periphery of a stranded conductor.