JPS63302713A - Aerial transmission line - Google Patents

Abstract

PURPOSE:To prevent galloping fault, by mounting a twist preventer having a distance G upto the center of gravity of transmission line onto the transmission line having outer diameter of D and setting such relation as G<=2D+70. CONSTITUTION:A twist preventer 2 having weights 5 at opposite ends of a rod member 4 suspended from a fixing portion 3 is mounted on a transmission line 1. Data employing the distance G upto the center of gravity of the twist preventer 2 as parameter shows that galloping fault occures in the area above line A. Fault shown by mark X occurs when the distance G upto the center of gravity of twist preventer 2 is long, and the distance G has a relation with the outer diameter D of the transmission line. In other word, line A represents a relation G=alphaD+70(where, alpha=2), and since fault does not occur in the area below line A, the twist preventer 2 is preferably fixed in the area below the line A where a relation G<=2D+70 is satisfied.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an overhead power transmission line that prevents snow accumulation and gear ropping on the overhead power transmission line.

[Prior Art] If gear lopping occurs on an overhead power transmission line, it may cause a disconnection accident of the transmission line, so a torsion preventer with a weight hanging down is attached to the transmission line to prevent the occurrence of gear lopping. As such a technique, the present applicant previously proposed a twisting period T of the electric wire.
Focusing on the fact that when R and the vertical cycle TV match, gear lopping increases, the moment of inertia Id and restoring moment Kd of the twist preventer are adjusted so that the twisting cycle TR of the wire and the vertical cycle TV do not match, and gear lopping is achieved. We have developed the technology disclosed in Japanese Patent Application Laid-open No. 15512/1983 to prevent this.

[Problems to be Solved by the Invention] As mentioned above, power transmission lines to which twist preventers are attached are limited to single conductors, and after various studies on current power transmission lines, it was found that the twisting period TR and vertical period TV of the wire Gear ropping is observed even when the values do not match, and d is the inertia moment ld and restoring moment of the twist preventer when TR≠TV
It has been found that it is not sufficient to simply adjust the cable so that gear ropping occurs; the size of the power transmission line and the position of the center of gravity of the twist preventer are extremely closely related to preventing gearropping.

Therefore, the present invention provides a technique that reliably prevents gear lopping accidents by determining the center of gravity position of the twist preventer in accordance with the outer diameter of the electric wire.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides an overhead power transmission line equipped with a torsion preventer in which a weight hangs from a wire attachment part, and a method for improving the center of gravity of the torsion preventer. When the distance is G and the outer diameter of the wire is D, the G of at least one or more twist preventers installed in the span is selected so that G≦2 D + 70' is satisfied. This is what I did.

[Function] According to the results of various studies, it has become clear that in order to prevent gear-ropping accidents, it is necessary to adjust the distance G to the center of gravity of the twist preventer to correspond to the outer diameter of the wire. According to research results, the above G is G≦2D
It has been found that gear lopping accidents do not occur when +70 is satisfied. Therefore, by installing a twist preventer with G selected as described above, it becomes possible to prevent gear roping of the power transmission line.

[Examples] Examples of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is an overhead power transmission line, and 2 is a twist preventer attached to this power transmission Ill. As shown in FIG. 5.

FIG. 3 shows research data on the occurrence of gear lopping actually measured on the overhead power transmission line 1 to which the twist preventer 2 is attached as described above, and the x mark indicates the occurrence of an accident due to gear lopping.

D is the outer diameter of the power transmission line 1 (m), G is the distance from the center of gravity of the twist preventer 2 to the center of the power line (m), M is the mass of the twist preventer 2, and the inertia of the twist preventer 2 Moment I
d(-・d), the restoring moment of the twist preventer 2 is d
(kg-m/rad), Id= M G %
Kd=M'G, and Id/Kd=MG2/MG
=G, therefore, the performance data shown in the third figure uses the distance G to the center of gravity of the anti-twist device 2 as a parameter.

As can be seen from Fig. 3, the cross mark indicating the occurrence of an accident due to gear lopping is above the straight line A, and when the above G is above the straight line A, that is, the distance G to the center of gravity of the anti-twist device 2 is It can be seen that the accidents marked with an x occur when the time is long, and this is related to the outer diameter of the power transmission Ill.

The straight line A is a line of G = aD + 70 (a = 2: constant), and since no gear-ropping accidents occur below the straight line A of G = 2D + 70, gear-ropping accidents can be prevented. It can be seen that the torsion preventer 2 to be attached to the power transmission line 1 for this purpose only needs to have a distance G to its center of gravity equal to or less than the above-mentioned straight line A, that is, G≦2D+70.

For example, for a power transmission line with an outer diameter of 301 ml, gear lopping accidents can be prevented by setting the distance G to the center of gravity of the twist preventer 2 as G≦2×30+70=130 m.

Torsion preventer 2 with the distance G to the center of gravity selected as described above.
Gear lopping accidents are prevented by attaching the torsion preventer 2 to the power transmission line a1, but the twist preventer 2 attached to the overhead power transmission line has at least one twist preventer installed in the overhead power transmission line span. G is the above G≦2
It is necessary to select so as to satisfy D+70.

As mentioned above, how to prevent gear-ropping accidents from occurring
Since it is necessary to reduce G as G≦2D+70, in order to obtain the predetermined Id and Kd, the above 1d=MG
2. If G of Kd = MG is decreased, the mass M will be increased, and as the transmission line becomes thicker, the mass per twist preventer will become heavier, but it is necessary to divide the transmission line appropriately and adjust the diameter of the transmission line. If the cables are installed in a distributed manner within the span, stress concentration at the attachment point will be alleviated, and the mass of the power transmission line will be non-uniform within the span, which can be expected to have the advantage of making it difficult for slight wind vibrations to occur.

As is clear from FIG. 3, the smaller the distance G, the less the influence on the power transmission Ill when the anti-twist device 2 is installed, and therefore, as in the conventional case, the moment of inertia Id=MG2 and the moment of restoring Kd=of the anti-twist device 2. It can be seen that increasing G and reducing the mass M in order to obtain the predetermined Id and Kd of the MG has an economical advantage of reducing the mass, but it is negative from the viewpoint of preventing gear roping.

In fact, gearropping vibration is likely to be induced when a large torsion preventer of 12G is installed in the center of the transmission line span, and this is because the torsional rigidity of the wire is weaker as it is located in the center of the span. This is because the restoring moment of the torsion preventer becomes large, but in such a case, the torsion preventer of the present invention with a reduced distance G to the center of gravity should be installed in the center of the span as described above. By doing so, accidents such as tripping near the center of the span and entanglement of wires, which conventionally occur, can be prevented.Instead of having the twist preventer configured as shown in Figure 2, it is possible to prevent accidents such as trips near the center of the span and entanglement of wires. As long as twisting can be prevented, the structure may be modified as appropriate.

[Effects of the Invention] As mentioned above, in the present invention, when installing a torsion preventer with a distance G to the center of gravity on a power transmission line with an outer diameter D, the distance G is selected so as to satisfy G≦2D+70. By doing so, it is possible to reliably prevent gear-ropping accidents that conventionally occur.

[Brief explanation of the drawing]

FIG. 1 is a drawing showing an overhead power transmission line according to an embodiment of the present invention;
Fig. 2 is a drawing showing the twist preventer, and Fig. 3 is a drawing showing the occurrence of gear lopping. 1: Overhead transmission line 2: Anti-twist device 3: Wire attachment part 5: Weight D = wire outer diameter

Claims (1)

[Claims] In an overhead power transmission line in which a torsion preventer with a distance to the center of gravity of G is attached to a transmission line with an outer diameter of D, the G of at least one of the torsion preventers installed in the span is set to G.
An overhead power transmission line selected to satisfy ≦2D+70