Electricity: conductors and insulators – Conduits – cables or conductors – Combined
Reexamination Certificate
2000-01-06
2002-04-09
Reichard, Dean A. (Department: 2831)
Electricity: conductors and insulators
Conduits, cables or conductors
Combined
C174S108000
Reexamination Certificate
active
06369328
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a power transmission wire heat dissipator wound around an aerial power transmission wire or other power transmission wire for dissipating the heat of the power transmission wire, a power transmission wire (line) equipped with a heat dissipator, and a method for attaching a heat dissipator on a power transmission wire.
BACKGROUND ART
It is desired to increase the power transmission capacity of an aerial line (wire).
When the power transmission capacity is increased, the current flowing through the line becomes heated. Therefore, a permissible upper limit is set on the current flowing through the aerial line.
Therefore, the general method of increasing the transmission capacity of an aerial line is use of an aerial line having a larger sectional area.
In the case of an already strung aerial line, the transmission capacity is increased by replacing it with another line having a larger sectional area.
However, a line having a large sectional area becomes heavier in the weight of the line per unit length, so the amount of sagging (sag or slack) becomes larger due to the line's own weight. If the sag becomes larger, the distance to the ground etc. becomes shorter, so the towers must be made higher and must be made stronger in structure in some cases. Such replacement of towers is difficult in view of on-going operations, work, and costs in many cases. When replacing a tower with one having a higher height and greater strength or fabricating a higher and stronger tower in advance so that a power transmission wire having a larger sectional area will be able to be laid in the future, the problems of a rise of the manufacturing cost of the tower and a rise of the transmission cost are encountered. Also, when the transmission capacity is further increased, the above problem of an increase in the amount of heat generated in the aerial line is still encountered.
As one method of overcoming the problem of the increase of the sag, use has been made of aerial lines made of twisted steel-reinforced aluminum conductors (ACSR)—conductors reinforced by Invar steel wires having a small coefficient of linear expansion and known for low sag. When newly stringing an aerial line made of Invar-reinforced aluminum conductors, the problem of the height of the tower can be overcome since the sag of the ACSR aerial line is small. When trying to increase the transmission capacity of an aerial line made of Invar-reinforced aluminum conductors, however, the number of aluminum conductors has to be increased or the sectional area of the aluminum conductors has to be enlarged. The weight of the aerial line is therefore increased so an excessive load is applied to the tower, and the price of the aerial line becomes remarkably high. Accordingly, the above problem cannot be overcome just by using ACSR for the aerial line.
Further, as one method of overcoming the problem of the large heat generation explained above, use has been made of aerial lines made of thermo-resistant conductors able to withstand high temperature use. For example, if an aerial line made of steel-reinforced ultra thermo-resistant aluminum alloy conductors (UTACSR) is used, usage at a high temperature of 200° C. or more is possible. Heating, however, causes the aerial line to elongate. In particular, the increase of the sag of the aerial line at the time of a high temperature cannot be ignored. Therefore, the problem of an increase of the sag is still encountered if just using UTACSR for the aerial line.
Japanese Unexamined Patent Publication (Kokai) No. 64-81110 and Japanese Unexamined Patent Publication (Kokai) No. 64-81111 disclose a technique of covering the outer circumference of the aerial line with a mesh belt so as to prevent the accumulation of snow from causing a tubular mass of snow (snow tubes) from depositing on the outer circumference of the aerial line, increasing the weight of the aerial line, causing sag and in turn breaking the aerial line. However, the technique disclosed in Japanese Unexamined Patent Publication (Kokai) No. 64-81110 and Japanese Unexamined Patent Publication (Kokai) No. 64-81111 is a technique considering only the prevention of tubular accumulation of snow, and not a technique for increasing the transmission capacity of the aerial line. Particularly, Japanese Unexamined Patent Publication (Kokai) No. 64-81110 and Japanese Unexamined Patent Publication (Kokai) No. 64-81111 do not disclose a technique for increasing the transmission capacity of an aerial line by improving the heat dissipation characteristic of the aerial line.
Japanese Unexamined Patent Publication (Kokai) No. 48-72688 (Japanese Unexamined Patent Publication (Kokoku) No. 52-4357) discloses a technique of preventing galloping, which frequently occurs when there is uniform accumulation of ice and snow along a longitudinal direction of the windward side of an aerial line by winding an S-twist and Z-twist helical shaped body having a predetermined length around the outer circumference of the aerial line so that the S-twist and the Z-twist are arranged repeatedly or at random. However, Japanese Unexamined Patent Publication (Kokai) 48-72688 also does not disclose a technique of increasing the transmission capacity of an aerial line by improving the heat dissipation characteristic of the aerial line.
Japanese Unexamined Patent Publication (Kokai) No. 49-101876 (Japanese Examined Patent Publication (Kokai) No. 53-14146) discloses a technique of reducing the noise due to wind pressure on the aerial line by setting the outer diameter of the strands and the outer diameter of the line of a low noise line comprised of strands wound helically or cross-wise and setting the winding pitch to within a predetermined range. However, Japanese Unexamined Patent Publication (Kokai) No. 49-101876 also does not disclose a technique of increasing the transmission capacity of an aerial line by improving the heat dissipation characteristic of the aerial line.
Japanese Unexamined Patent Publication (Kokai) No. 57-98907 (Japanese Examined Patent Publication (Kokoku) No. 58-38884) discloses an aerial line reducing the corona noise of the aerial line by providing a low noise line comprised of a line around the outer circumference of which strands are wound where a plurality of unit strands formed with minute unevenness on the surface of the wound strands are arranged in close contact. However, Japanese Unexamined Patent Publication (Kokai) No. 57-98907 also does not disclose a technique of increasing the transmission capacity of an aerial line by improving the heat dissipation characteristic of the aerial line.
Japanese Unexamined Patent Publication (Kokai) No. 6-302223 discloses reducing the noise due to wind pressure and, further, reducing an AN level by providing a low noise line in which part of the outermost layer of the aerial line is made to project out. However, Japanese Unexamined Patent Publication (Kokai) No. 6-302223 also does not disclose a technique of increasing the transmission capacity of an aerial line by improving the heat dissipation characteristic of the aerial line.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a heat dissipator to be attached on a power transmission wire in order to enable an increase of the transmission capacity without an increase of the sectional area of the power transmission wire itself.
Another object of the present invention is to provide a heat dissipator to be attached on a power transmission wire in order to enable an increase of the transmission capacity without an increase of the sectional area of the power transmission wire itself and, further, to enable prevention of accumulation of snow, reduction of noise due to wind pressure, reduction of the corona noise, and prevention of galloping.
Still another object of the present invention is to provide a power transmission wire on which the heat dissipator is attached in order to enable an increase of the transmission capacity without an increase of the sectional area of the power transmission
Knobbe Martens Olson & Bear LLP
Nino Adolfo
Reichard Dean A.
The Furukawa Electric Co. Ltd.
LandOfFree
Heat dissipating device for transmission line, transmission... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Heat dissipating device for transmission line, transmission..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Heat dissipating device for transmission line, transmission... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2877817