JPH0614441A - Prevention method of ground fault trouble caused by overhead earth wire disconnection - Google Patents

Abstract

PURPOSE:To prevent a ground fault trouble by coupling among overhead earth wires through a large number of spacers, and making smaller mounting intervals of a larger number of spacers than intervals between the overhead earth wires and upper phase power lines. CONSTITUTION:One overhead earth wire 2 is connected to the other overhead earth wire 2 through a large number of spacers 4, and mounting intervals A of a large number of spacers 4 make smaller than intervals L between the overhead earth wires 2 and upper phase power lines 3. The spacers 4 are mounted in a stage to apply tensile force to expansion spring sections 5. When the overhead earth wires 2 are disconnected by the falling of a thunderbolt, etc., the overhead earth wires 2 hang down, and the mounting intervals A of the spaces 4 are smaller than the intervals between the overhead earth wires 2 and upper phase power lines 3, so that the sagging overhead earth wires 2 are not brought into contact with the upper phase power lines 3. According to the constitution, a ground fault trouble can be surely prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of preventing a ground fault from occurring when an overhead ground wire is cut by a lightning strike or the like in an overhead power transmission line.

[0002]

2. Description of the Related Art If there is a lightning strike on an overhead ground wire, the overhead ground wire may be disconnected. In order to prevent such disconnection of the overhead ground wire, an overhead ground wire with a protective layer in which a metal protective layer is formed on the outer periphery of the overhead ground wire has been proposed. This overhead ground wire with a protective layer protects the overhead ground wire inside from being damaged by a lightning strike by the metal protective layer. However, even with this overhead ground wire with a protective layer, the metal protective layer may not be able to completely protect it depending on the size of the lightning strike, and the overhead ground wire may be cut.

When the aerial ground wire is cut, the aerial ground wire hangs down, so that it may come into contact with an electric power line installed below the aerial ground wire to cause a ground fault.

[0004]

SUMMARY OF THE INVENTION As described above, conventionally,
Measures such as providing a metal protective layer on the overhead ground wire have been taken to prevent the overhead ground wire from being cut, but no measures have been taken when the overhead ground wire is cut.
The present invention is an aerial structure that prevents a ground fault accident from occurring when the aerial ground wire is cut and the aerial ground wire that is cut contacts the upper phase power line installed below. It is intended to provide a method of preventing a ground fault accident by cutting the ground wire.

[0005]

In order to solve the above-mentioned problems, the present invention is to connect an overhead ground wire to another overhead ground wire or a support wire installed along the overhead ground wire through a number of spacers, It is characterized in that the mounting intervals of a large number of spacers are made smaller than the intervals between the overhead ground wire and the upper phase power line.

[0006]

According to the above construction, if the overhead ground wire is cut due to a lightning strike or the like, the hanging length of the overhead ground wire will be within the spacer mounting interval. Since the space between the spacers is smaller than the space between the overhead ground wire and the upper phase power line,
The hanging ground wire will not come into contact with the upper phase power line. Therefore, the ground fault can be surely prevented.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows an embodiment of a ground fault accident prevention method by cutting an overhead ground wire according to the present invention. Reference numeral 1 is a steel tower, 2 is an overhead ground wire extending from the top of the steel tower, and 3 is an upper-phase power line installed below the overhead ground wire 2 (the middle-phase power line and the lower-phase power line are not shown).

The two overhead ground wires 2 are connected by a large number of spacers 4 mounted at a predetermined interval A in the longitudinal direction. The mounting interval A of the spacer 4 is set smaller than the interval L between the overhead ground wire 2 and the upper phase power line 3.

Therefore, as shown in FIG. 2, even if the overhead ground wire 2 is cut and hangs down due to a lightning strike or the like, the overhead ground wire 2 does not come into contact with the upper phase power line 3, and a ground fault can be reliably prevented.

Further, the illustrated spacer 4 has an expansion / contraction spring portion 5 composed of a coil spring or the like in the middle, and is attached to the expansion / contraction spring portion 5 in a tensioned state. When the spacer 4 having the elastic spring portion 5 in the middle is used as described above, when the overhead ground wire 2 is cut, the spring portion 5 is contracted and the cut overhead ground wire 2 is pulled upward, so that a ground fault accident can be more reliably performed. Can be prevented.

FIG. 3 shows another embodiment of the present invention. In this embodiment, a support wire 6 is installed between two overhead ground wires 2, and the support wire 6 and each overhead ground wire 2 are connected by a large number of spacers 4. The mounting distance A of the spacer 4 is smaller than the distance L between the overhead ground wire 2 and the upper phase power line 3, and that the spacer 4 has a telescopic spring portion 5 in the middle, which is the same as the above-mentioned embodiment. .

With such a structure, as in the above embodiment,
Even if the overhead ground wire 2 is disconnected, it does not come into contact with the upper phase power line 3, and a ground fault can be reliably prevented.

4 and 5 show still another embodiment of the present invention. In this embodiment, support wires 6 are installed below the overhead ground wire 2, and the support wire 6 and the overhead ground wire 2 are connected by a large number of spacers 4, respectively. Spacer 4
The installation interval A of is smaller than the interval L between the overhead ground wire 1 and the upper layer power line 2.

Even with such a structure, when the overhead ground wire 2 is cut off, it does not come into contact with the upper phase power line 3 and the ground fault can be reliably prevented. Further, since the support line 6 is installed below the overhead ground wire 1, there is no possibility that the support line 6 will be damaged by a lightning strike.

In the above embodiment, the case where the present invention is applied to an overhead power transmission line having two overhead ground wires is shown, but the present invention is also applicable to an overhead power transmission line having one overhead ground wire. Applicable to The structure of the spacer used in the present invention is not particularly limited. Further, the overhead ground wire to which the present invention is applied may be not only a normal overhead ground wire but also an overhead ground wire with a protective layer.

[0016]

As described above, according to the present invention, an overhead ground wire is connected to another overhead ground wire or a supporting wire through a large number of spacers, and the mounting intervals of the large number of spacers are different from the overhead ground wire. Since the spacing is smaller than the upper phase power line, even if the overhead ground line is disconnected due to lightning, etc., the overhead ground line will not come into contact with the upper phase power line, and ground faults can be reliably prevented. it can.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a ground fault accident prevention method according to the present invention.

FIG. 2 is a perspective view when the overhead ground wire is cut in FIG.

FIG. 3 is a perspective view showing another embodiment of the present invention.

FIG. 4 is a perspective view showing still another embodiment of the present invention.

5 is an enlarged view of a main part of FIG.

[Explanation of symbols]

 1: Steel tower 2: Overhead ground wire 3: Upper phase power line 4: Spacer 5: Spacer expansion / contraction spring part 6: Support line A: Spacer mounting interval L: Space between overhead ground wire and upper phase power line

Claims (1)

[Claims] 1. An overhead ground wire is connected to another overhead ground wire or a support wire installed along the overhead ground wire through a large number of spacers,
A method for preventing a ground fault by cutting an overhead ground wire, characterized in that a mounting interval of the plurality of spacers is set smaller than a distance between the overhead ground wire and an upper phase power line.