JPH0197123A - Ice and snow coating prevention type electric wire - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an improvement in an ice-and-snow prevention electric wire that is configured to actively prevent ice and snow from accumulating on the electric wire.

[Conventional technology and problems] Wire disconnection accidents and tower collapse accidents caused by ice and snow accretion on electric wires, as well as phase-to-phase short circuit accidents of electric wires caused by gear-ropping vibration caused by wing-shaped ice and snow accumulation. ,
Major accidents are reported every winter.

Therefore, in order to prevent such accidents, attempts have been made to attach rings to electric wires or form fin-like protrusions on the electric wires, and these efforts have been found to be effective to some extent. However, all of these methods use the weight of the ice and snow attached to the wires to create an imbalance in the gravity of the ice and snow themselves, thereby encouraging the ice and snow to fall from the wires. In some cases, the effects could not always be expected.

A surefire way to prevent ice and snow from accumulating on electric wires is to heat the wires to melt and fall the ice and snow. As a concrete example, proposals have been made for a long time, such as twisting heater wires. However, if an attempt was made to heat an overhead power transmission line using a heater wire, for example, it would require a large amount of electricity, and this has not been achieved in the end.

In recent years, the use of heat pipes as a new means of heating electric wires has attracted attention, and the applicant has already made a proposal.

A heat pipe is a pipe made of copper, stainless steel, aluminum, etc., in which a working liquid such as water, fluorocarbon, ammonia, or methanol compound is sealed, and the working liquid is heated at one end of the pipe, that is, at the heat absorption part. This gas is vaporized and condensed in the heat dissipation section of the pipe, causing the pipe to generate heat by utilizing heat dissipation.The heat energy given in the heat absorption section is rapidly transported in the longitudinal direction of the pipe,
This heat is used to heat the object to be heated, that is, the above-mentioned electric wire. The condensed working fluid is returned to the heat absorbing section using capillary action and the above operation is repeated.

According to this heat pipe heating method, it is considered that the heat pipe is attached to the electric wire and thermal energy is applied to a localized heat absorption part of the heat pipe, so that it is relatively feasible. However, at present, electric wires are generally installed overhead above supporting structures such as steel towers, and thermal energy is transferred from above the support structure to the heat absorbing part of the heat pipe attached to such electric wires. It is not always easy to find a way to provide this. For this reason, even if we look at the actual proposals to date, only the application of the heating principle of heat pipes has been emphasized, and in reality, in such a hypothetical state, there is no concrete way to apply thermal energy to the heat absorption part of the heat pipe. In many cases, the question of what measures to take would be left unresolved. Therefore, the inventors previously proposed as a simple and reliable means for heating the heat pipe, arranging a magnetic material in the heat absorption part of the heat pipe attached to the electric wire. The current flowing through the wire causes the magnetic material to generate heat due to hysteresis loss. However, in this case, there is a problem in that the magnetic material generates heat not only at low temperatures when ice and snow occur, but also at high outside temperatures, because the magnetic material is energized by the electric wire. A switch mechanism was needed.

[Summary of the Invention] The present invention has been made in view of the above-mentioned circumstances, and uses a heat source that provides heat energy to a heat pipe.
In a configuration in which a magnetic body having a simple structure is attached to the electric wire, the magnetic body generates heat using the electric current flowing through the electric wire, and the generated heat is used to heat the heat absorption part of the heat pipe. By using a low Curie point material for part or all of the material and selecting the Curie point close to the freezing and snow formation temperature, the magnetic material is intended to have a switching function for heat generation.

[Example] The present invention will be described below based on examples.

FIG. 1 is an explanatory diagram showing an example of the case where the present invention is applied to an overhead power transmission line as a specific example. A heat pipe 3 is wound around the electric wire 1, and a magnetic body 2 is attached along the outer periphery of the electric wire 1 in contact with the heat absorbing portion 3a of the heat pipe 3.

With the above configuration, when the electric wire 1 is energized, the magnetic body 2 suffers hysteresis loss due to the energized current.
Eddy current loss occurs, and the magnetic body 2 generates heat thereby.

The heat generated in the magnetic body 2 is transferred to the heat absorption part 3 of the heat pipe 3.
As a result, the heat pipe 3 generates heat as described above, causing the ice and snow attached to the electric wire 1 to melt and fall.

Incidentally, the significance of attaching the magnetic body 2 and the heat pipe 3 to the electric wire 1 as described above is truly significant.

That is, there have been proposals for a long time to try to melt ice and snow on the electric wire 1 by using only the heat generation phenomenon of the magnetic body 2, but in that case, the magnetic body must be attached to the electric wire at extremely narrow intervals. , there are accompanying problems such as an increase in the weight of the wires, an increase in the wind pressure load due to the increase in the outer diameter of the wires, and reinforcement of the strength of the wires and towers. The heating effect does not extend to a position farther away from the magnetic material.

By combining the magnetic body 2 and the heat pipe 3, the heat generated by the magnetic body 2 does not remain localized as described above, but heat transport occurs quickly through the heat pipe 3, and the electric wire 1
Heat transfer occurs in the longitudinal direction of the electric wire 1, causing the ice and snow adhering to the electric wire 1 to evenly melt and fall.

However, since the magnetic body 2 in the above configuration generates heat as long as the electric wire 1 is energized, heat is generated even at high temperatures higher than the freezing and snowing temperature, resulting in large losses.

In the present invention, a low Curie point material is interposed in a part of the magnetic body 2, as shown in FIG. 21.

The melting point of this low melting point material is selected near the outside temperature at which freezing and snow formation occurs. A material having such a Curie point can be appropriately selected from iron-nickel-chromium alloys and the like.

By configuring a magnetic closed circuit as shown in Figure 2,
Magnetic material 2 at temperatures below the cue point where icing and snow increase.
A type of switch effect can be expected in which the heat generation of the magnetic body 2 increases, and the heat generation of the magnetic body 2 decreases at a temperature above the cue point. Even if the magnetic body 2 itself is made of such a low-cure point material 21, the same effect can be achieved.

Note that FIGS. 3 and 4 are explanatory sectional views showing two embodiments regarding the arrangement of the heat pipe 3, in which the heat pipe 3 is wound around the outer circumference of the electric wire 1 instead of being wound around the outer circumference of the electric wire 1 as shown in FIG. The strands 1a and 1a are mixed and twisted, and may be selected as necessary.

[Effects of the Invention] As described above, according to the electric wire according to the present invention, by using the heat pipe, the efficiency of heat transfer can be significantly improved, and in addition, a magnetic material can be used as the heat source. This makes it possible to simplify the structure and use the current flowing through the wires, and also allows the magnetic material to have a switch function, thereby suppressing unnecessary operation under weather conditions where icing and snow do not occur. The significance of being able to drastically reduce losses due to unnecessary operations is enormous.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an example of the electric wire according to the present invention, Fig. 2 is an explanatory cross-sectional view showing an example of the configuration of the magnetic material according to the present invention, and Figs. 3 and 4 are diagrams showing the arrangement of the heat pipe. FIG. 2 is an explanatory cross-sectional view showing two types of embodiments. 1: Electric wire, 2: Magnetic material, 21: Low-cure point material, 3: Heat pipe, 3a: Heat absorption part of heat pipe. Agent Patent Attorney Fujio Sato;

Claims (1)

[Claims] (1) In an electric wire that prevents ice and snow from forming, a heat pipe is arranged in the longitudinal direction of the electric wire, and a part or all of the magnetic substance is attached to a heat absorption part of the heat pipe with a magnetic substance for heating the heat absorption part. An icing and snow prevention electric wire made of a low Curie point material having a Curie point near the freezing and snowing temperature.