JPH0134503Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an overhead power transmission line that can prevent snow accumulation.

In general, in areas with heavy snowfall, snow adheres to overhead power lines, but when the amount of snow increases, the weight of the power lines increases, resulting in large tension on the lines, which can lead to disconnection accidents and other problems. This may cause inconvenience. Conventionally, in order to prevent snow from accumulating on power transmission lines, magnetic metal wires (now referred to as low Curie metal wires), which turn into ferromagnetic materials through magnetic transformation at temperatures below the allowable heat generation temperature when energized, were spirally attached to power transmission lines. At low temperatures such as snowfall, the low-Kyrie metal wire becomes ferromagnetic and generates heat, which melts the snow. However, even if a low-Kyrie material becomes ferromagnetic at low temperatures, it has a lower magnetic susceptibility than a ferromagnetic material such as iron, and is therefore not efficient in obtaining a sufficient amount of heat. In addition, since low-Kyuri materials are expensive,
Normally, wires with a small diameter are used, but if the diameter is small, the cross section of the power transmission line will be broken into a non-circular shape, preventing the generation of Karman vortices and reducing wind noise.

This idea was made in view of the above circumstances,
The object of the present invention is to obtain an overhead power transmission line that has a sufficient snow melting effect and can also prevent wind noise.

An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the overhead power transmission line of the present invention has a wire body 2 spirally wound around the outer periphery of a bare stranded wire conductor 1.
It is formed by connecting in series a ferromagnetic metal wire 3 having a length of 100 times or less, and a magnetic metal wire 4 that becomes ferromagnetic at a temperature below the allowable heat generation temperature of the power transmission line when energized.

Note that the above-mentioned filament body 2 has an aluminum alloy coating 2 on its outer periphery, as shown in the cross-sectional view in FIG. 2, for example.
It is preferable to use a material in which a is formed. When coated with aluminum alloy, bare stranded conductor 1
It is possible to prevent electrolytic corrosion from occurring between the surface of the

In addition, as the magnetic metal wire 4, examples of suitable materials that become ferromagnetic at temperatures below the allowable heat generation temperature of power transmission lines when energized include 60wt% iron, which becomes ferromagnetic at temperatures below 150°C, and nickel.
A quaternary alloy consisting of 53.5 wt% iron, 37 wt% nickel, 9 wt% chromium, and 0.5 wt% silicon that becomes ferromagnetic at temperatures below 90°C. Alloys, etc. can be raised.

Next, the effect will be explained.

At a temperature below the permissible heat generation temperature of the power transmission line when energized, for example when it is snowing, the magnetic metal wire 4 exhibits a ferromagnetic state. Therefore, at this time, the filament 2 is magnetically a continuous ferromagnetic material over its entire length, and since the continuous length of the ferromagnetic material exceeds 100 times its own diameter, the magnetic circuit is It is essentially closed. Note that in order to promote heat generation in a ferromagnetic material, generally the magnetic circuit must be closed, that is, the ferromagnetic material must form a closed loop, but even if a ferromagnetic material does not form a closed loop, It has been experimentally confirmed that if the length L of the wire meets the relationship L≧100d with the diameter d, a state substantially similar to that of a closed magnetic circuit will occur. Therefore, the alternating current flowing through the power transmission line generates eddy currents in the filamentary body 2, and magnetic hysteresis occurs, which causes eddy current loss and hysteresis loss, causing the filamentous body 2 to generate heat. . This heat generation can melt snow adhering to power transmission lines and prevent snow from accumulating on power transmission lines.

Further, at a temperature equal to or higher than the allowable heat generation temperature of the power transmission line, the magnetic metal wire 4 becomes a paramagnetic material. In other words, at this time, the filament 2 does not exhibit a ferromagnetic state over its entire length, but the ferromagnetic metal wire 3 has an appropriate length of 100 times or less its own diameter due to the magnetic metal wire 4 interposed in series. It becomes magnetically divided. To generate heat using magnetism,
As mentioned above, the magnetic circuit of the ferromagnetic material is closed around the current source, or the length L of the ferromagnetic metal wire is
must be at least 100 times its diameter d, so
In this state where the magnetic circuit is no longer open, no heat generation phenomenon occurs in the ferromagnetic metal wire 3 either.
Therefore, the power transmission line will not be unnecessarily heated and softened.

In addition, the above-mentioned linear body 2 has a more desirable heat generation property compared to one in which a magnetic metal material (i.e., a low Curie material) 4 that turns into a ferromagnetic material at a temperature below the allowable heat generation temperature of the power transmission line is used over the entire length. have characteristics. That is, the low Curie material 4 in the example,
The magnetization characteristics of the ferromagnetic metal wire 3 are as shown in FIG. 3, and the magnetic susceptibility of the ferromagnetic metal wire 3 [solid line (A)]
is larger than the magnetic susceptibility of the low Curie material 4 [broken line (b)]. Therefore, the amount of heat generated when the filament 2, which is made by connecting the low-Kyuri material 4 and the ferromagnetic metal wire 3 in series, becomes a ferromagnetic material over the entire length is that the filament 2 is all low-Kyuri. This is much larger than the amount of heat generated when it is made of material 4. In addition, in FIG. 3, t ₀ indicates the maximum allowable heat generation temperature of the power transmission line.

Further, by selecting the diameter of the filament 2 so as to substantially break the cross-sectional outer peripheral shape of the power transmission line into a non-circular shape and inhibit the generation of Karman vortices, it is possible to reduce the wind noise level.

As explained above, the overhead power transmission line of the present invention has a ferromagnetic metal wire with a length of 100 times or less than its own diameter, and a wire body spirally wound around the outer periphery, and a temperature that is below the allowable heat generation temperature of the power transmission line when energized. Since it is formed by connecting in series a magnetic metal wire that is ferromagnetic, in low temperature conditions such as during snowfall, the entire wire becomes a continuous ferromagnetic material, that is, The magnetic circuit essentially closes and generates heat due to energization, effectively preventing snow from accumulating on power transmission lines, and magnetic metal wire becomes paramagnetic at temperatures above the allowable heat generation temperature of power transmission lines. At the same time, each ferromagnetic metal wire is magnetically divided into its own lengths and the magnetic circuit is opened, so that no heat generation occurs in the wire as a whole, thus making the power transmission line unnecessary. There is no heating, and there are no inconveniences such as power transmission loss or softening of power transmission lines. Furthermore, since the above-mentioned heat generation properties can be obtained by only partially using a magnetic metal material (low-Kyuri material), it is possible to provide the striated body and therefore the snow accretion prevention device at a low cost, and furthermore, its heat generation properties are During snowfall, the ferromagnetic metal wire with high magnetization properties works effectively and generates sufficient heat, making it highly effective at melting snow. In addition, the diameter of the filament can be increased to provide a wind noise prevention effect, and various other excellent effects can be achieved.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a side view of an overhead power transmission line, Fig. 2 is a sectional view showing another embodiment of the wire body in Fig. 1, and Fig. 3 is a magnetization It is a characteristic diagram. DESCRIPTION OF SYMBOLS 1... Bare stranded wire conductor, 2... Wire body, 3... Ferromagnetic metal wire, 4... Magnetic metal wire.

Claims (1)

[Scope of utility model registration request] In an overhead power transmission line in which a wire body 2 is spirally wound around the outer periphery of a bare stranded wire conductor 1, the wire body 2 is connected to a ferromagnetic metal wire 3 having a length of 100 times or less than its own diameter and the power transmission line tolerance when energized. An overhead power transmission line characterized in that it is formed by connecting in series a magnetic metal wire 4 that becomes ferromagnetic at a temperature below the heat generation temperature.