JPS591049B2 - overhead power transmission line - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an overhead power transmission line that reduces electrostatic induction on the line of the overhead power transmission line.

Generally, in order to eliminate the adverse effects caused by electrostatic induction on the lines of overhead power transmission lines, a shielding wire made of a conductor is installed below the overhead power transmission lines installed between the towers on the ground side.

Conventionally, this shield wire had to be electrically connected to the ground in order to reduce electrostatic induction, so both ends of the shield wire were connected to the steel tower.

For this reason, the shielding wire forms a closed loop between the tower and the shielding line, one tower, and one tower, and electromagnetic induction occurs in the shielding wire due to the influence from the overhead power transmission line, causing an induced current to flow.

This induced current is relatively small for normal power transmission lines of about 500KV, so it does not pose a problem. However, when the power transmission line has a large capacity, for example, about 100OKV, the induced current becomes large, and the shielding wire must be made with a large diameter. There is a problem with the need to re-sort the pipe.

In view of the above circumstances, the present invention is capable of reliably reducing electrostatic induction due to the influence of power transmission lines, and at the same time, significantly reduces the induced current flowing through the shield wire compared to the conventional method, thereby reducing the wire diameter of the shield wire.・
”・It was made so that it could be treated as a small thing.

This will be explained based on an example shown in the figure.

In the figure, 1 and 2 are steel towers, 3 is an overhead power transmission line, and 4 is an electrostatic induction shielding line, and the overhead power transmission line 3 is supported on the steel tower 1.2 in a conventional manner.

This method of support employs restraints and suspensions.

The shield line 4 is installed below the overhead power transmission line 3 on the ground side.

In the other construction, one end of the shielding wire 40 is secured to the steel tower 1 via a retaining metal fitting 5 and an insulating material 6, for example, an insulator device such as a semiconductive insulator or a normal insulator, and the other end is in a conductive state, for example, as a shielding wire. A retaining fitting 5 with four terminals fixed is directly retained on a steel tower 2.

Therefore, one end of the shield wire 4 is tied to the steel tower via an insulating material, so that it does not create an electrically closed loop with the earth, and the other end is connected to the steel tower in a conductive state, so that it is grounded to the earth. and is configured to have the same potential as the ground.

However, according to the present invention, since the shield wire is grounded to the earth and has the same potential as the earth, even if an electric charge is generated in the shield wire due to electrostatic induction from the overhead electric wire, the resulting current flows to the earth, i.e. The shielding wire has the same potential as the ground, in other words, it has zero potential, thus producing a sufficient shielding effect.

Also, if the shielding line forms a closed loop with the ground,
The magnetic field from the overhead power transmission line interlinks with the closed loop formed by the shielded wire, and a current flows through the shielded wire due to electromagnetic induction from the overhead power transmission line. However, in the present invention, as described above, the shielded wire is constructed so as not to form a closed loop with the ground. Therefore, no current due to electromagnetic induction from overhead power lines flows through the shielded wires.

Therefore, even if the power transmission capacity of the power transmission line is increased, it is sufficient to consider only the current due to electrostatic induction when determining the wire diameter of the shield wire, and thus the wire diameter of the shield wire can be made smaller than that of conventional products.

[Brief explanation of drawings]

The figure is an explanatory diagram illustrating one embodiment of the overhead power transmission line of the present invention. 1.2... Steel tower, 3... Overhead power transmission line, 4... Shield wire, 5... Holding fitting, 6... Insulating material.

Claims (1)

[Claims] 1. In an overhead power transmission line in which an electrostatic induction shield wire is installed on the ground side below the overhead power transmission line installed between steel towers, the shield wire is grounded to the earth and is not electrically closed loop with the earth. An overhead power transmission line characterized by being constructed between steel towers.