JPS6031385Y2 - power cable termination box - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an improvement of an electric cable termination box.

With conventional air termination boxes, insulating mixtures or insulating oil are filled into the insulating pipes on-site, which reduces workability and
There was a problem in terms of working hours.

This is particularly problematic when installing a termination box on a steel tower.

Further, when the voltage of the cable is high, the insulator tube becomes long, so the area in which the external semiconducting layer at the end of the cable is removed also becomes long, and this operation requires a lot of time.

Furthermore, the longer the area of removal of the outer semiconducting layer, the more difficult it is to apply the stress cone.

Slip-on air termination boxes have been proposed to eliminate the various drawbacks mentioned above.

In this termination box, the insulating tube section filled with an insulating compound, oil, etc. is assembled in advance in the factory, filled with an insulating compound, and then attached to the cable end in a slip-on manner on site. .

Its typical structure is shown in FIG.

That is, an epoxy seat 4 is attached to the lower end of the insulator tube 1, and a conductor pull-out rod 10 that passes through the insulator tube and the high voltage shielding electrode 3 in an airtight manner is attached to this epoxy seat.

The inside of the insulator tube 1 is filled with oil 2.

A tulip contact 13 is provided at the lower end of the conductor pull-out rod 10, which cooperates with a cable terminal 12 provided at the end of the cable conductor 11.

At the site, we carried an insulator pipe filled with oil and placed 5 stress cones.
Cover the cable terminal that has been finished with terminal processing such as installation.
The assembly is completed by engaging the cable terminal 12 and the tulip contact 13.

In the slip-on type termination box having the above configuration, in order to fill the insulator tube 1 with oil 2 in advance, the high-voltage shielding electrode 3 is embedded in the epoxy seat 4 that protrudes from the bottom of the insulator tube into the insulator tube. .

Therefore, as shown by the equipotential lines in FIG. 1, the electric field is biased toward the lower part of the insulator tube 1, and the flash voltage may decrease in the lower part of the insulator tube 1 where the distribution of equipotential lines is dense.

In order to prevent the above-described drop in flash fault voltage, various electric field mitigation measures have been taken in the past.

The first step is to provide a sufficiently large distance between the high voltage electrode and the ground electrode, but this method has the disadvantage of requiring a special stress cone.

Second, as shown in Fig. 2, the stress cone 5 is placed below the insulator tube 1, the epoxy seat 4 is extended to the outside of the insulator tube 1, and after ensuring sufficient insulation thickness at the extended portion, the mounting bracket is attached. 6,
Some use a ground side electrode formed by the lower part of the insulator tube metal fitting 7 or the like to alleviate the electric field.

When this is done, the size of the lower part of the insulator becomes very large, and therefore the size of the entire termination box also becomes large, which has the disadvantage of requiring a large space for installation.

The present invention was developed based on the above circumstances, and can alleviate the electric field concentration at the bottom of the insulator tube due to the high-voltage shielding electrode.
Moreover, to provide an electric cable termination box that does not require a special stress cone or a large space for installation.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

In FIG. 3, a cylindrical earth electrode 9 is attached to the outer circumferential surface of the base of the epoxy seat 4, which terminates above the earth electrode 8 embedded in the epoxy cabinet.

In the termination box of the present invention having the above structure, the bias of the electric field at the lower part of the insulator tube 1 is eliminated as shown by the equipotential lines e1 to e, and a drop in the flash voltage at the lower part of the insulator tube 1 is prevented. .

Therefore, in the present invention, since a ground electrode is only added to the outer periphery of the epoxy seat base, a special stress cone is not required, and the termination box is large and requires a large installation space. do not have.

[Brief explanation of the drawing]

1 and 2 are sectional views of a conventional terminal box, and FIG. 3 is a sectional view of an embodiment of the present invention. 1...Insulator, 2...Oil, 3...
・High voltage shielding electrode, 4... Epoxy seat, 5---
---Stress cone, 8°9... Earth electrode.

Claims (1)

[Scope of utility model registration request] An insulator tube, an epoxy seat protruding into the insulator tube attached to the bottom of the insulator tube and having a high-voltage shielding electrode on its inner peripheral surface, and a conductor pull-out rod that penetrates the epoxy seat and the top surface of the insulator tube in a liquid-tight manner;
In one having oil filled in an insulator pipe, a cylindrical earth electrode buried in the epoxy storage, and a tulip contact provided at the lower end of the conductor pull-out rod and cooperating with a cable terminal of a cable conductor terminal, An electric cable termination box characterized in that a cylindrical earth electrode that terminates above the earth electrode is attached to the outer periphery of the epoxy seat.