JPS61293114A - Semistopper for oil-filled power cable - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is applied to a semi-stop device provided in a junction box for oil-filled cables.

[Conventional technology]

Generally speaking, semi-stop devices for oil-filled cable junction boxes include:
Some have valves and some don't.

However, in a semi-stop device with a valve, one end of the visible tube is attached to a semi-stop cylinder such as a lead pipe, which is oil-tightly attached to a cable core and a metal sheath such as an aluminum sheath. A stop valve opening/closing connector is installed, and this semi-stop valve opening/closing connector is installed oil-tightly through the cylindrical body of the junction box, such as a steel pipe, and the pressure difference between the insulating oil inside and outside the semi-stop can be adjusted from outside the junction box. This is done by opening/closing the semi-stop valve opening/closing connector.

According to this, if a pressure difference occurs between the inside and outside of the semi-stop after construction, it is necessary to adjust the pressure difference each time.

On the other hand, a semi-stop device without a valve is constructed by attaching a semi-stop cylinder made of lead or the like to a cable core and a metal sheath such as aluminum in an oil-tight manner. If it is necessary to adjust the pressure difference inside and outside the body, the junction box must be dismantled.

[Problem that the invention seeks to solve]

By the way, when an oil-immersed power cable is installed on a route with a high head, semi-conductors may occur in the connection box on the low side of the cable when the connection box is dismantled or reinstalled for some reason after installation. A high pressure difference occurs between the inside and outside of the stop due to the drop in the route.

This high pressure difference between the inside and outside of the semi-stop can cause abnormalities such as buckling, stretching, and bulging of the insulating paper of the cable core, and when connecting the junction box and metal sheath with lead wire, the inside of the cable metal sheath may be exposed to high hydraulic pressure. When carrying out lead work under such conditions, the high temperature of the burner flame may damage the cable metal sheath.

With the conventional semi-stop device described above, it is difficult to quickly respond to these problems.

[Means and effects for solving the problems] The present invention has the following features:
In order to solve the above-mentioned problems of the conventional technology, a safety valve is attached to the semi-stop cylinder provided between the cable core and the cable metal sheath, and the opening/closing response value when the safety valve receives pressure is set to a predetermined value. By setting this value to a value, the semi-stop device for oil-filled power cables automatically adjusts the pressure difference when a pressure difference occurs between the inside and outside of the semi-stop.

〔Example〕

This will be explained below with reference to the drawings.

Figures 1 and 2 show two embodiments of the semi-stop device for oil-filled power cables according to the present invention; Figure 1 is a fixed type, and Figure 2 is a movable type.

In the figure, 1 is a metal sheath such as aluminum, 2 is a cable core made of a conductor and insulating paper, 3 is a semi-stop cylinder such as a lead pipe, 4 and 5 are semi-stops on the metal sheath 1 and cable core 2. This is a seal portion for attaching the cylinder 3 in an oil-tight manner.

In the movable type shown in FIG. 2, one end of the slide tube 3b is inserted into the part of the cylinder 3a, such as a lead pipe, which is oil-tightly attached to the metal sheath 1 by a seal 4 and protrudes from the end of the metal sheath. While the binding wire 6 is wound from above and installed in an oil-tight manner, the packing member 8 is installed on the cable core in an oil-tight manner using the binding wire 9, and the packing member 8 is installed on the cable core in an oil-tight manner.
is slidably in contact with the inside of the slide tube 3b, and the relative movement between the metal sheath 1 and the cable core 2 is absorbed by the mutual sliding contact between the slide tube 3b and the packing member 8. There is.

Reference numeral 10 denotes a safety valve provided according to the present invention, which is oil-tightly attached to the semi-stop cylinder 3.3a so as to communicate with the cylinder, and is arranged to protrude outside the cylinder 3.3a.

Although not particularly shown in the drawings, these semist knob portions are provided inside a cylindrical body of a connection box, such as a copper pipe, which is oil-tightly attached to the metal sheath 1.

The safety valve 10 has a structure as shown in FIG. 3, for example.

The valve body 11 made of a cylindrical body has a tapered thread 12 formed on the outer surface of one end in the axial direction.
By screwing the part into the screw hole 3C formed in the semi-stop cylinder 3, it can be oil-tightly attached to the semi-stop cylinder 3. A surface 13 is formed.

The valve 14 has a valve seat portion 16 in which a sealing gasket 15 is incorporated in the pressing surface corresponding to the surface 13, and a threaded rod 17 integrated with the valve seat portion 16 is inserted into the cylindrical portion of the valve body 11. A coiled spring 18 is inserted into the valve body 11 from the mouth on the tapered screw side, and one end of the coil spring 18 is assembled so as to come into contact with an inward shoulder at the mouth of the valve receiver surface 13. By pressing the nut 20 screwed into the threaded rod 17 against the spring receiver 19 provided at the other end of the nozzle, the sealing gasket is pulled into the valve body by the elastic force of the coiled spring 18. The tapered valve receiver 15 is designed to be pressed tightly against the surface 13 at all times.

If a pressure difference occurs between the inside and outside of the semi-stop cylinder 3 and the internal oil pressure becomes so high that it becomes stronger than the elastic force of the coiled spring 18, the valve seat portion 16 is moved back by the high oil pressure and the sealing gasket 15 is moved back. However, the valve receiver is in a so-called open state where it is separated from the surface 13, and the oil inside the semi-stop flows out of the semi-stop, thereby automatically adjusting the pressure difference between the inside and outside of the semi-stop.

When the pressure difference between the inside and outside of the semi-stop is balanced, the valve seat part 1
6 is pulled into the valve body 11 by the elastic force of the coiled spring 18 which is compressed during operation, and the sealing gasket 15 is automatically returned to the original sealed state in which the valve seat is pressed against the surface 13. It is something.

In such a safety valve, the pressure difference between the inside and outside of the semi-stop can be set to the amount of pressure to be adjusted by adjusting the amount of spring compression by the amount of screwing of the NAND 20 into the threaded rod 17.

〔Effect of the invention〕

As explained above, the semi-stop device for oil-filled power cables of the present invention applies the pressure difference between the inside and outside of the semi-stop cylinder installed oil-tightly between the cable metal sheath and the cable core to the semi-stop cylinder. Since the installed safety valve automatically opens and closes to adjust the value below a predetermined value, the high pressure difference that occurs between the inside and outside of the semi-stop can cause abnormalities such as buckling, stretching, and bulging of the insulating paper of the cable core. In addition, the pressure difference between the inside and outside of the semi-stop can be adjusted without dismantling the junction box or performing operations from outside the junction box, so cables can be installed on high-head installation routes. Easy connection work, etc.
The effect on cable installation and cable maintenance is significant.

[Brief explanation of drawings]

FIGS. 1 and 2 are explanatory diagrams showing two embodiments of the semi-stop device for oil-filled electrical capacitors of the present invention, and FIG. 3 is an explanatory diagram showing an example of a safety valve in the semi-stop device for oil-filled electrical capacitors of the present invention. be. 18 cable metal sheath 2: cable core 3: semi-stop cylinder body 10: safety valve

Claims (1)

[Claims] 1. A semi-stop device for an oil-filled power cable, characterized in that a safety valve is provided in a semi-stop cylinder provided between a cable core and a cable metal sheath.