JPH0216553B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Use The present invention is applicable to devices such as earth arresters connected to power distribution lines when their characteristics deteriorate due to damage or aging and they are no longer able to maintain an insulating state. This relates to a disconnection device that automatically disconnects equipment from power distribution lines and prevents grounding accidents caused by this equipment.

(b) Prior Art A conventional type of the above-mentioned separating device is described in Japanese Patent Publication No. 49-42298, which was previously filed by the present applicant. The structure of this conventional device is as shown in FIG. That is, in a cylindrical case 2 made of an insulator and having a groove 1 formed in a part of the inner circumferential wall, a gap g consisting of an upper electrode 3 and a lower electrode 4, a resistor 5 connected to both ends of the gap g, and Explosive 6 heated by resistor 5
an upper terminal 7 whose openings at both ends are electrically connected to the upper electrode 3 and the lower electrode 4, respectively.
and is closed by the lower terminal 8. This disconnection device a is connected between the power distribution line L and the ground E in series with, for example, an earth protector b, as shown in FIG. With this connection, the disconnection device a may be connected to the power distribution line L side as shown by the solid line, or may be connected to the earth E side as shown by the broken line.

In this connected state, when a surge voltage occurs on the distribution line L due to a lightning strike, lightning arrester B operates,
A discharge occurs in the gap g and absorbs the surge voltage. This causes the power distribution line L to return to normal voltage.

However, if the performance of lightning arrester b deteriorates due to aging or other reasons, the distribution line L
A leakage current due to the normal ground voltage applied between the ground and the ground will flow to the ground E. However, the temperature inside the cylindrical case 2 gradually rises due to the Joule heat generated when these currents flow through the resistor 5, and when this temperature reaches several hundred degrees, the explosive 6 suddenly explodes due to this temperature, and the cylindrical case 2 explodes. A shaped case 2 is cut at a part that is mechanically weakened by the groove 1. This breaks the electrical connection between the upper terminal 7 and the lower terminal 8 and completely disconnects the lightning arrester b from the distribution line L.
It is possible to prevent this grounding accident of the power distribution line.

However, since the conventional disconnection device a performs the disconnection operation by detonating the explosive 6 contained therein, it generates a loud sound during operation and becomes a source of noise. Therefore, if there are residential buildings nearby, there are restrictions on installation.

Furthermore, since the explosive 6 is incorporated, the material cost is high, and the assembly has to be carried out in a special factory capable of handling hazardous materials, so there is a drawback that the manufacturing cost is high. Furthermore, if the explosive 6 absorbs moisture, it loses its blasting ability, so in this respect it was necessary to be careful in handling it.

C. Purpose of the Invention An object of the present invention is to provide a separating device that does not use explosives and has an extremely simple structure, thereby preventing noise generation and reducing manufacturing costs.

D. Structure of the Invention The present invention comprises a cylindrical body 9 made of thermoplastic resin, and an upper terminal 1 fitted and fixed to openings at both ends of the cylindrical body.
0 and a lower terminal 11, and a resistor 1 having both ends electrically connected to the upper terminal and the lower terminal and housed in the cylindrical body together with a compression coil spring.
2, a gap G is formed at a position facing the upper terminal and the lower terminal, and an annular groove is formed at a parting position of the cylindrical body corresponding to the gap.

E. Example 3 showing an example of the separating device A of the present invention.
In the figure, 9 is a cylindrical body made of thermoplastic resin such as polyethylene, 10 is a bowl-shaped part 10a to be fitted into an opening at one end of the cylindrical body, and a male screw 10b protruding from the back surface of the bowl-shaped part 10a. an upper terminal having 11
is a bowl-shaped portion 11 into which the other end opening of the cylindrical body 9 is fitted;
a and a cable attachment pipe 11b protruding from the back surface of the bowl-shaped portion 11a.A lower terminal 12 is housed in the cylindrical body 9 together with a compression coil spring 13, and both ends are electrically connected to the upper terminal 10 and lower terminal 11. G is the resistor connected to the end of the bowl-shaped portion 11a of the upper terminal 10 and the bowl-shaped portion 11a of the lower terminal 11.
The gap is formed by opposing the ends of the gap. The resistance value of the resistor 12 determines the current sensitivity of the disconnection operation, and is set to an appropriate value. For high-speed operation, this resistance value should be, for example, several kilohms to tens of kilohms.
Let it be Ω.

To assemble this disconnection device A, adhesive is applied to both ends of the cylindrical body 9 in which the compression coil spring 13 and the resistor 12 are housed, and the upper terminal 10 is attached thereto.
This is done by fitting the lower terminal 11. By this fitting, one electrode of the resistor 12 is directly connected to the lower terminal 11, and the other electrode of the resistor 12 is connected to the upper terminal 10 via the compression coil spring 13.

Separation device A of the present invention manufactured as described above
is connected between the distribution line L and the ground E in a state in which it is connected in series to the lightning arrester b as shown in FIG. 2, and operates as follows.

When lightning arrester b is normal, when an abnormal surge due to a lightning strike occurs on the distribution line L, the surge arrester b becomes in a state of discharging it to the ground, and the gap G of the disconnection device A becomes in a flash fault state. . As a result, when the abnormal surge is discharged to the ground E, the lightning arrester b blocks the follow-on current and returns to the normal state.

On the other hand, when lightning arrester b is damaged or its characteristics deteriorate due to aging, and it is no longer able to maintain the ground voltage of distribution line L, disconnection device A performs the following operation to disconnect lightning arrester b from distribution line L. Or separate it from the earth E.

When the characteristics of the lightning arrester b deteriorate and the ability to maintain the ground voltage is lost, a ground fault current flows from the lightning arrester b to the earth E through the resistor 12 between the upper terminal 10 and the lower terminal 11 of the disconnection device A. The resistor 12 generates heat due to this ground fault current. As a result, the cylindrical body 9 made of thermoplastic resin is heated and rapidly softened, and finally, due to its own weight on the lower terminal 11 side and the biasing force of the compression coil spring 13, it moves up and down at a certain part of the gap G. To separate. The lightning arrester b is then completely disconnected from the distribution line L or the earth E.

In this state, the disconnection device A is divided into two parts, so it can be easily found when inspecting and inspecting the distribution line L for maintenance. and lightning arrester b
It is possible to know that the characteristics have deteriorated and take appropriate measures such as replacement work.

Further, even when the disconnection device A of the present invention is used in combination with other power distribution equipment, it is effective in preventing accidents because it detects and operates a current that could lead to a ground fault.

Note that an annular groove 14 is provided at the dividing position of the cylindrical body 9 corresponding to the position of the gap G to facilitate fusing.
may be formed. Further, it is desirable that the thermoplastic resin used for the cylindrical body 9 has a softening temperature and a melting temperature close to each other.

F. Effects of the Invention Since the present invention does not use explosives and performs the disconnection operation by fusing the thermoplastic resin, no explosion noise is generated during operation. Therefore, there is no need to consider noise countermeasures, and the degree of freedom in installation increases.

In addition, the number of parts is extremely small compared to conventional ones, and assembly requires only applying an adhesive and fitting them together, so manufacturing costs can be significantly reduced.

In addition, the thermoplastic resin forming the cylindrical body 9 is chemically stable compared to thermosetting resin, so that it can be installed outdoors, exposed to rain, direct sunlight, etc., like the grounding wire disconnection device of the present invention. It is also suitable as a material for items exposed to severe temperature changes.

In addition, the operating characteristics can be easily adjusted by adjusting the depth of the annular groove provided on the outer periphery of the cylindrical body, and the internal pressure increases due to the elastic force of the compression coil spring, the weight of the resistor, and the heat generated by the resistor. Thus, the cylindrical body can be reliably fused and separated.

Furthermore, since the fusion-cut separation of the cylindrical body occurs at a portion corresponding to the gap, it can be visually observed from the outside, making inspection rounds easier.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a conventional grounding line disconnection device, Fig. 2 is a circuit diagram showing the device connected between the distribution line and the ground together with a lightning arrester, and Fig. 3 is a grounding device according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of the wire cutting device. 10... Upper terminal, 11... Lower terminal, 12...
...Resistor, 13...Compression coil spring, G...
...Gap, A... Ground wire disconnection device.

Claims (1)

[Claims] 1 A cylindrical body made of thermoplastic resin, an upper terminal and a lower terminal that are fitted and fixed into openings at both ends of the cylindrical body, and both ends electrically connected to the upper terminal and the lower terminal to form the cylindrical body. and a resistor housed in the body along with a compression coil spring, and a gap is formed at a position facing the upper terminal and the lower terminal, and an annular groove is formed at a dividing position of the cylindrical body corresponding to the gap. A grounding wire disconnection device featuring: