JPS59175321A - Snow fusing system of aerial 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] This invention relates to the improvement of overhead power transmission and distribution lines used in cold regions9, and particularly relates to a snow melting system for overhead power lines that can melt snow and ice. .

In cold regions such as northern Japan and southern Japan, snow and ice accrete on overhead transmission and distribution lines during the winter, and this increases the size of the wires, increases the weight of the wires between the tower spans, and increases the wind pressure load. This often leads to accidents such as increased slack in the wires, breakage of the wires due to excessive tension, and even collapse of steel towers. In addition, if ice and snow fall in the form of blocks, not only is there a danger to people passing under the overhead wires, but even if the area under the overhead wires is agricultural land, there is a risk of damaging crops, vinyl houses, etc. There is a demand for a solution to this problem since it causes social problems.

For this reason, the methods known to date to prevent snow accumulation are methods such as temporarily transmitting large currents to melt the conductor using Joule heat, and attaching ring-shaped objects to power transmission lines to allow snow to fall off. There are methods to do this, but the former method is subject to restrictions on power system operation, so it cannot be implemented freely.

The effectiveness of the latter method differs depending on the type of ice and snow that adheres to power transmission lines, and furthermore, if a grown block of ice and snow is simply dropped, there will be no chance of a secondary disaster occurring at the point where it falls. do not.

For this reason, it is possible to wrap a sleeve made of magnetic material, a linear body processed into a spiral shape, a tape, or a rond on the AC power transmission line, so that the AC magnetic field caused by the power transmission current passes through the sleeve, etc. A method of melting using heat loss due to hysteresis loss and eddy current loss has been proposed, but heat generation from magnetic materials at temperatures where ice and snow do not occur increases power transmission loss, so high temperatures are not recommended. In some cases, it is considered desirable to use a material with a low Curie point because its magnetic properties deteriorate and it no longer generates heat.

However, even when a magnetic material with such a low Curie temperature is used, if it is constantly wrapped around the surface of the wire, it cannot necessarily be said that the reduction of unnecessary heat generated at room temperature is sufficient. be.

As a result of various studies, the present inventor has provided a snow melting system for overhead power transmission and distribution lines that solves the above-mentioned difficulties by using a filament made of a shape memory alloy in combination with a magnetic material.

Next, the present invention will be explained with reference to the drawings.

FIG. 1 shows an example of a magnetic element used in the present invention, which includes a hollow cylindrical magnetic layer 1 made of a low-Kyrie material, and a hollow cylindrical aluminum element 3 closely attached to the outside thereof. Second
The figure shows such a magnetic element 3 as a shape memory alloy filament 4.
It is shown that the magnetic element-attached shape-memory alloy filament 5 is constructed by inserting the magnetic element-attached shape-memory alloy filament 5 continuously in a bead-like manner.

6 to 4 are front views illustrating the snow melting system for overhead electric wires of the present invention. The shape memory alloy linear body to which the magnetic element is attached is indicated by a line in these figures, but it is specifically as shown in FIG. 2.

First, FIG. 3 shows a state in which a magnetic element-attached shape memory alloy filament 5 is wound helically around an overhead electric wire 6 at a temperature of about 0° C. at a pitch Po.

The radius of the spiral is ρ0.

If snow or ice builds up on these power lines.

Naturally, the snow melting action occurs quickly due to the heat generated by the magnetic element that is in close contact with the overhead electric wire 6, and the temperature of the overhead electric wire increases. However, in FIG. 6, the magnetic element 3 is inserted into the shape memory alloy wire body 4 which loosens and deforms when the temperature reaches room temperature. ,
When the close contact between the magnetic element 3 and the overhead electric wire 6 is broken, the winding pitch becomes larger, or a combination thereof occurs.

The state is shown in Fig. 4←), (b) and (c). First, FIG. 4 shows a state in which the magnetic element-attached shape-memory alloy filament 5 that is wound is heated to room temperature, relaxed, and changes in the winding pitch or the winding radius. In Fig. 4(a), compared to Fig. 3, when the pitch of the helix due to winding is P1 and the radius of the wound helix is ρ1, ρ1) A partial front view in the case of ρOs Pl > PO, and Fig. 4(b) shows a partial front view showing the case where the winding radius of the spiral is unchanged compared to Fig. 3 and only the pitch Pl becomes very large, ρ0-ρo, Pl>>PO, and a partial front view showing the case where Pl>>PO. In FIG. 4(C), both the pitch P1 of the spiral and the radius ρ1 of the winding spiral are much larger than those in FIG. 3, and is a partial front view showing the case where ρ, )ρ01P□)P2.

If the deformation as shown in FIG. 4 occurs, the magnetic element 3 attached to the shape memory alloy filament 4 will be less likely to be in close contact with the overhead wire 6, thereby preventing unnecessary temperature rise of the overhead wire 6. It turns out.

Next, FIG. 5 shows the initial winding spiral radius ρ0 of the magnetic element-attached shape memory alloy filament 5. Radius due to subsequent relaxation ρ
, is an explanatory diagram of the wrapping angle θ.

In such a case, the calorific value H per unit length of the magnetic element is expressed by H=Coθθ/ρ if other parameters are the same. (θ: wrapping is angle) Therefore, if either ρ, θ or both ρ and θ increase,
Since Co5N decreases, ρ and θ at room temperature become 0°C.
If the shape is memorized so that it is larger than the nearby ρ and θ, that is, the shape memory alloy wire is ideally straight at room temperature, this will work well with the low Curie property of the magnetic material. Therefore, the amount of heat generated at room temperature can be significantly reduced compared to that at around 0°C.

In carrying out the present invention, the magnetic element 3 attached to the shape memory alloy filament can be further moved by opening the outlet of the central hole at both ends, as shown in FIG. will be smooth.

In addition, when winding the shape memory alloy wire, one end or the center is fixed to the overhead wire, and the rest is left free, which makes the shape memory alloy wire more likely to deform. This has the advantage that the relative movement distance between the spirally wound magnetic element-attached shape-memory wire and the overhead electric wire is smaller than that of the fixed IM.

It should be noted that the shape memory alloy used in the present invention needs to have reversible shape memory properties, but in order to increase the calorific value as much as possible in near wet conditions (near 0°C), it is necessary to If it has magnetism with low temperature characteristics, and/
Alternatively, it is desirable that the material has low conductivity.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of a magnetic element used in the present invention, FIG. 2 is a perspective view showing an example of a shape memory alloy wire body equipped with such a magnetic element, and FIG. 6 is a perspective view showing an example of the magnetic element. Front view showing the state in which the fitted shape memory alloy filament is spirally wound around the overhead electric wire near O'C, Figures 4 (a), (b) and (
c) are shown in Figure 6, Figure 5 is an explanatory diagram of the winding angle and radius of the shape memory alloy wire body attached to the magnetic element, Figure 6
The figure is a longitudinal sectional view showing another example of the structure of the magnetic element. 1: Low conductivity conductor 2: Magnetic alloy 3: Magnetic element 4: Shape memory alloy filament 5: Shape memory alloy filament fitted with magnetic element 6: Overhead wire agent Patent attorney Mamoru Takeuchi Figure 1 Figure 2 9J, 3rd figure 4 (/I1 1, 51 shi 1 Figure 6 Procedural amendment (voluntary) May 6, 1980 Commissioner of the Japan Patent Office Kazuo Wakasugi 1, Indication of the case 1988 Patent Application No. 48770 2, Name of the invention Snow melting system for overhead electric wires 3, Relationship to the amended case Patent applicant address 5-1 Kiba-chome, Koto-ku, Tokyo Name (5)
18) Fujikura Electric Cable Co., Ltd. Representative: Makoto Kagaya - 4, Agent Address: 101 Address: 2-15-13 Uchikanda, Chiyoda-ku, Tokyo The detailed description of the invention and the brief description of the drawings in the Nanbu Pill Specification Columns and drawings (Figures 4 and 5) 6. Contents of the amendment As per attached sheet (1) On page 5, line 13 of the specification, the statement "ρ0 = ρ0" has been amended to "ρ1 = ρO" do. (2) On the 177th line of the same page, the statement rP, PtJ is corrected to read rP1PoJ. (3) On page 6, line 4 of the specification, after the phrase "wrapping angle θ", add the phrase "and pitch P". (4) On the 6th line of the same page, the statement "rH=cosθ/ρ" is corrected to "haboH=c0s0". ρ (5) On the 8th line of the same page, delete the phrase ``If the pitch is P.'' (6) On the 10th line of the same page, the statement "r Cos θ/ρ" is corrected to "Do1L". ρ (7) Page 7, line 20 of the specification, “(a), (b) and 0
→” should be amended to read “r (a) (b) and (C)”. (8) Page 8, line 3 of the specification, “Wrapping angle and...
・", the phrase "wrapping angle, pitch, and..."
: Corrected as follows. (9) Figures 4 and 5 of the drawings shall be corrected as shown in the attached drawings.

Claims (1)

[Scope of Claims] A shape memory alloy wire having the following characteristics, in which magnetic elements are attached in the form of beads on the surface of an overhead power transmission/distribution line, is wound with one end or center fixed and the other end or both ends free. (1) A snow melting system for overhead power lines that is characterized by the following: (1) A snow melting system for overhead power lines that maintains its coiled shape at a predetermined pitch around the overhead power lines at temperatures around 0°C, and transforms into a loose state at room temperature.