JPS6332008B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a termination box for an SF ₆ gas insulated switchgear direct connection type power cable.

FIG. 1 shows a vertical sectional view of the left half of a conventional power cable termination box of this type. In the figure, 1 is a conductor pull-out rod, and 2 is an epoxy resin tube, which is sealed with the pull-out rod 1 and lower support fitting 7 by gaskets 3, and cable insulating oil 9 is sealed inside. 4 is the case of gas insulated switchgear (hereinafter referred to as GIS)
It is locked to the bottom of the tube 2 by a locking metal fitting 6 (referred to as a case) and supported by a lower support metal fitting 7. 8 is auxiliary insulating paper wrapped around the cable core 11. 10 is a conductor connection part.

Note that SF ₆ gas is sealed in the case 4 of the gas insulated switchgear.

As shown in Fig. 1, in the conventional termination box described above, the interface between the SF ₆ gas 5 and the cable insulating oil 9 is sealed by the gasket 3 on both ends of the epoxy tube 2, but the function of the gasket seal 3 is impaired. If
If SF ₆ gas entered the cable or insulating oil entered the switchgear, the insulation performance of either of them was threatened, creating a danger.

The present invention has been constructed as described below in order to eliminate the above-mentioned drawbacks.

FIG. 2 shows a vertical cross-sectional view of the left half of a terminal box embodying the present invention. Note that the same parts as in FIG. 1 are indicated by the same symbols.

In the figure, reference numeral 12 denotes a stop unit provided on the conductor pull-out rod 1, which is formed by molding with epoxy resin.

Also, the connection part 1 between the conductor pull-out rod 1 and the cable conductor
0 is provided on the opposite side (lower in the figure) from the switchgear attached to the stop unit 12. The lower end of the tube 2 and the mounting portion of the stop unit 12 are fixed to both sides of the mounting bracket 14, respectively, to form an airtight chamber in which the pressure medium 13 is sealed between the tube and the stop unit.

A communication hole 15 is provided in the mounting bracket 14 to communicate with the small chamber, and a pressure medium pressure monitoring or medium supply device 16 is connected to the outside.

The pressure medium is insulating oil or SF ₆ gas, and in the case of SF ₆ gas filled, the pressure is set to be lower than the pressure of cable insulating oil 9, and in the case of insulating oil, it is set to be lower than the pressure of SF ₆ gas 5. It should be set high.

With the above configuration, even if the function of the gasket 3 should be impaired, there is no risk that the SF ₆ gas 5 inside the GIS case 4 will enter the cable system.

In other words, if insulating oil is sealed in an airtight chamber, the oil will either flow into the GIS case or into the cable, and if gas is sealed, the cable insulating oil will flow into the chamber or the GIS As SF ₆ gas flows in and the gas pressure increases, abnormalities can be easily detected using an oil leak detection device or an oil pressure or gas pressure alarm device in the small chamber.

Conventionally, as a preventive measure, the oil supply system for OF cables was designed under the condition of oil pressure > gas pressure, which resulted in high system oil pressure and the need to increase the internal pressure resistance of the cable and accessories, making it extremely expensive. However, the present invention has the advantage of being cheaper.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the left half of a conventional SF ₆ gas-insulated switchgear direct connection type power cable termination box, and FIG. 2 is a sectional view of the left half of the same termination box in which the present invention is implemented. 1 is a conductor pull-out rod, 2 is an epoxy resin tube,
3 is gasket, 4 is GIS case, 5 is SF ₆ gas,
6 is a locking metal fitting, 7 is a lower support metal fitting, 8 is an auxiliary insulating paper, 9 is a cable insulating oil, 10 is a conductor connection part, 1
1 is a cable core, 12 is a stop unit, 1
3 is a pressure medium, 14 is a mounting bracket, 15 is a communication hole,
16 is a pressure medium pressure monitoring or medium supply device.

Claims (1)

[Scope of Claims] 1. In a termination box for a power cable directly connected to an SF ₆ gas insulated switchgear that directly connects a power cable to an SF ₆ gas insulated switchgear, the portion that directly connects the power cable to the SF ₆ gas insulated switchgear is: An insulating stop unit 12 having a center penetrating conductor formed of epoxy resin and integrally formed with the conductor pull-out rod 1 is provided on the outer periphery of the conductor pull-out rod 1, and the stop unit 12 has the following features: , is connected to the cable conductor of the power cable via a conductor connection part 10 formed at the end of the conductor pull-out rod 1, and the other SF ₆ gas insulated switchgear side of the stop unit 12 is connected to the center through conductor in an airtight manner. In the said SF ₆ gas insulated switchgear side, the tube 2 is pulled out.
a connecting hole 15 which is covered by a pressure medium and communicates with an external pressure medium pressure monitoring or medium supply device 16;
A mounting bracket 14 having a mounting bracket 14 forms an airtight chamber for enclosing a pressure medium 13, and the pressure medium 13 is insulating oil or SF ₆ gas;
When the pressure medium 13 is SF ₆ gas, the pressure is set to be lower than the pressure of the cable insulating oil 9, and when the pressure medium 13 is insulating oil, the pressure is set to the pressure of the SF ₆ gas 5 of the SF ₆ gas insulated switchgear. SF ₆ gas insulated switchgear direct connection type power cable termination box, which is characterized by being set at a higher pressure.