JPH0773070B2 - Disconnecting device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a device for disconnecting an electric circuit, and in particular, characteristics of a lightning arrester deteriorate due to lightning or the like, resulting in a large leakage current or interruption of a follow-up current after the arrival of a lightning surge. The present invention relates to a lightning arrester disconnecting device that disconnects a lightning arrester from a ground circuit when it is no longer possible to prevent a ground fault in a power system circuit.

[Conventional technology]

Lightning arresters, which are connected between live parts such as distribution lines and the ground and protect electrical equipment from abnormal voltage such as lightning surge, are generally
An element such as ZnO or SiC that has a low resistance when a high voltage is applied is used as a characteristic element.

In particular, a surge arrester using ZnO has an abnormal voltage absorption capability that allows even a large lightning surge to escape to the ground, and has a very excellent characteristic in the voltage-current characteristic of completely interrupting the normal ground voltage of the distribution line. To have.

However, ZnO, which is a characteristic element, receives the above-mentioned voltage − when it receives a large number of lightning surges or surges that greatly exceed the rating.
The current characteristics are inevitably deteriorated.

Due to this deterioration, the leakage current gradually increases, and if the energy at the time of lightning surge absorbing operation becomes excessive, the element starts to generate heat, and thermal runaway eventually causes short-circuit breakdown, resulting in a ground fault. Then, the ground fault relay or the like of the circuit to which the lightning arrester is connected is activated to have a great influence on the power system.

Therefore, in order to prevent this, the present applicant has proposed a disconnecting device (1) as shown in FIG. 12 (Japanese Patent Application Laid-Open No. 62-208581).
No.), as shown in FIG. 13 or FIG. 14, together with the arrester (2), it is connected between the charging section (3) such as a distribution line and the ground (4).

This disconnecting device (1) uses a conductive plastic (5), whose conductivity is selected so that it melts when the temperature rises to a predetermined value and functions as a heating resistor, as a terminal holder, and is fixed to both ends. A discharge gap G is formed between the metal terminals (6) and (6).

When an abnormal voltage such as a lightning surge occurs in the charging part (3), the disconnecting device (1) releases it to the ground (4) through the discharge gap G and the lightning arrester (2). When the lightning arrester (2) deteriorates and leak current increases, or when the lightning arrester is short-circuited and broken, it melts due to self-heating,
The upper and lower metal terminals (6) and (6) are separated, and the lightning arrester (2) is disconnected from the ground circuit. Such an operation prevents a ground fault in the power system circuit.

[Problems to be Solved by the Invention]

The conventional disconnecting device (1) has a problem that when the conductive plastic (5) is melted due to deterioration of the lightning arrester (2), the arc generated at this melting point is difficult to extinguish. Since the ground voltage of the charging part (3) such as distribution line is as high as several thousand volts, the cut ends of the fused conductive plastic must be separated by, for example, 30 cm or more to extinguish the arc, while separate metal terminals ( 6) (6) is because it is supported by a thick electric wire connected to it and is usually only a short distance depending on its own weight. If the follow-up current is not cut off in this way, it is necessary to perform a return operation at the substation, and it makes no sense to use the disconnecting device (1).

In addition, considering the case where the disconnecting device (1) normally disconnects, there are the following problems.

As shown in FIG. 13, the disconnecting device (1) has a lightning arrester (2).
If it is on the upper side, the electric wire (3a) connected to the upper metal terminal (6) will move as shown by the alternate long and short dash line after disconnecting, and it may hit other electric wires and cause a short circuit accident. , The disconnecting device (1) is attached to each phase of the three-phase distribution line together with the arrester (2), and the installation place is a place where the equipment such as the air switch is centrally arranged, so this is ignored It is a problem that cannot be done.

Next, as shown in FIG. 14, when the disconnecting device (1) is under the lightning arrester (2), the charging section in which the upper metal terminal (6) connected to the lightning arrester (2) after being disconnected is exposed. As it remains, it is dangerous.

In view of this, the present invention provides a disconnecting device capable of reliably interrupting the follow-up current when the conductive plastic is melted due to a defect of the lightning arrestor and the metal terminals are separated, and the disconnecting operation is performed by separating the internal metal terminals, but not the external shape. The purpose is to provide.

[Means for Solving the Problems]

(1) The disconnecting device of the present invention comprises a pair of metal terminals to be separated at both ends, a conductive plastic whose conductivity is selected so as to melt when a temperature rises to a predetermined value and to function as a heating resistor. An arc-extinguishing resin formed of a material that generates an arc-extinguishing gas by heating and independently surrounding each of the conductive plastics divided into two parts by fusing;
A tubular arc-extinguishing resin slidably mounted over the arc-extinguishing resin made of a member, a discharge gap formed between the pair of metal terminals, and a direction in which the pair of metal terminals are separated. Equipped with a biasing spring, the inner and outer arc extinguishing is performed until the outer cylindrical arc-extinguishing resin that slides out the arc-generating conductive plastic fusing part is removed from the arc-extinguishing resin consisting of the two inner members. It is characterized in that it is confined in a space surrounded by a resin.

(2) The arc-extinguishing resin composed of two members and the cylindrical arc-extinguishing resin that is exterior to the above-described structure (1) may be replaced with a two-member arc-extinguishing resin having the following structure. it can.

Ie. As shown in FIG. 5, two members (12) (which are formed of a material that generates an arc-extinguishing gas when heated and independently surround the conductive plastic (10) at each part divided by fusing are formed. 12), one member has a cylindrical shape with a bottom that slidably covers the outer peripheral surface of the other member, and the space where the melting point of conductive plastic that generates an arc is surrounded by two members of arc-extinguishing resin Can be locked inside.

(3) Further, the structures of (1) and (2) above can be enclosed in a closed case.

(4) When the sealed case is used as in (4) above, the fact that the conductive plastic is melted and the pair of metal terminals are separated is displayed on the outside of the sealed case as shown in FIG. A display section (18) can be provided.

(5) Further, when the closed case is used, it is possible to provide the closed case with a dangerous portion that opens to form a window hole when the inside has a high pressure.

[Action]

In the basic configuration of (1) or (2), when the lightning arrester deteriorates or short-circuits and breaks, the conductive plastic rapidly melts due to self-heating, and the metal terminal is separated by the spring.

The arc generated at the time of melting is the arc extinguishing action of the arc extinguishing gas generated by the heated arc extinguishing resin and the arc generated by the tension spring (22) separating the metal terminals (11) (11) into upper and lower parts. And the increase in pressure due to the generation of a large amount of gas due to the vaporization of the conductive plastic are simultaneously extinguished in a short time.

In particular, in these structures, the fusing part of the conductive plastic is confined within a small volume surrounded by the arc-extinguishing resin within a fixed time after the start of separation, so that the amount of arc-extinguishing gas generated is increased and The pressure rise can be made rapid and the arc extinguishing can be speeded up and ensured.

The sealed case in which the disconnecting device is enclosed holds inside the pair of metal terminals separated by fusing the conductive plastic. Then, the main disconnecting device is not separated into upper and lower parts, and the charging part is not exposed. Further, the hermetically sealed case shields each component of the present invention from the outside air and keeps its function for a long time.

The display unit displays that it has been operated in the closed case that is not separated by the disconnection operation, and facilitates the inspection work.

In addition, the dangerous area escapes the high-pressure gas that accompanies the melting of the conductive plastic, prevents the explosion and scattering of the sealed case, and guarantees safety.

〔Example〕

FIGS. 1 (a) to 1 (d) show a specific embodiment of the separating device (9) according to the present invention.

Before describing FIG. 1, only the basic configuration A will be described with reference to FIGS. 2 and 3.

In FIG. 2, (10) is a rod-shaped conductive plastic having a male screw formed over the entire length, and the conductivity is selected so that it melts when the temperature rises to a predetermined value and functions as a heating resistor. . This conductive plastic (10)
For example, it is preferably made of a synthetic resin mixed with a conductor powder such as metal or graphite, and metal plating is preferably applied to the surface of the metal terminal in order to reduce the contact resistance. (1
1) (11) is a rod-shaped metal terminal fixed to both ends of conductive plastic, the upper metal terminal (11) is a female screw at the inner end,
A male screw is formed on the outer end. The lower metal terminal (1
In 1), female threads are formed on both ends. (12) (12)
Is a first arc-extinguishing resin having a hat-shaped cross section, which is molded so as to surround the inner ends of the metal terminals (11, 11). First
The arc-extinguishing resin (12) (12) is made of Duracon,
A material such as urea resin that generates an arc-quenching gas such as H _{2 when} heated is used. Reference numeral (13) is a cylindrical second arc-extinguishing resin, which is slidably fitted onto the outer circumference of the first arc-extinguishing resin (12) (12) arranged with their top surfaces facing each other. This material is similar to the first arc extinguishing resin (12). (14) and (14) shown in FIGS. 3 (a) and (b) are gap metal fittings, which are formed by an L-shaped bent metal strip that forms a discharge gap G between the metal terminals (11) and (11). Has been formed.

An example of a manufacturing procedure of the basic configuration A of the separating device (9) will be described.

First, the first arc extinguishing resin (12) (12) is adhered to the inner ends of the metal terminals (11) (11) in a hat-shaped cross section. At this time, the shoulder portion (12a) of the top surface of the first arc extinguishing resin (12) (12) is chamfered. And one metal terminal (1
A male screw-shaped conductive plastic (10) is screwed onto the female screw (11a) of 1), and a cylindrical second portion is formed on the outer circumference of the first arc-extinguishing resin (12) of the metal terminal (11). Fit the arc-extinguishing resin (13) with a minute gap. Then, the protruding conductive plastic (10) is screwed into the female screw (11a) of the other metal terminal (11), and as shown in FIG. 2, both the first arc extinguishing resin (12) (12). Rotate until the top surface of touches.

After this, the gap metal fitting (14) shown in FIGS. 3 (a) and 3 (b).
The basic configuration A is constructed by fitting the (14) to the roots of the metal terminals (11) and (11) and making the V-shaped bent tip portions (14a) and (14a) face each other.

Next, return to FIGS. 1 (a) to 1 (d). The separating device (9) as a whole will be described.

In FIGS. 1 (a) to (d), (15) is a cylindrical hermetically sealed case in which the basic configuration A is assembled, and the inner peripheral surface is
Two parallel guide grooves (16) from the middle position to the lower end
(16) is formed, and is formed on the outer surface by an annular thin-walled portion as shown in FIG. 1 (a). ) And two parallel plate-like pieces (19) (19) forming the display section (18) are formed to project. Reference numeral (20) is a drawer fitting for sealing the upper end opening of the closed case (15), and (21) is a bush for closing the lower end opening of the closed case (15).

The basic structure A is installed in the closed case (15) by screwing the male screw (11b) of the upper metal terminal (11) into the drawer metal fitting (20).

Reference numeral (22) is a tension spring for urging the metal terminals (11) (11) in a direction to disconnect the metal terminals (11) (11). It is fixed to the terminal (11) and the push (21) at the lower end opening of the closed case (15). (22a) is the mounting bracket (23) (2
It is an electric wire that electrically connects 4).

The display section (18) is configured by swingably attaching a display body (26) to a pin (25) spanned between the plate-shaped pieces (19) and (19). The display body (26) is projected and retracted by a spring (27) that biases the display body (26) in a projecting direction and permanent magnets (28) (29) of different polarities that exert an attractive force. One permanent magnet (28) is embedded in the display body (26), and the other permanent magnet (29) is fixed to the lower metal terminal (11) in the sealed case (15) and is a disc-shaped guide member ( 29a). This permanent magnet (29) has a guide groove (1
Although it moves up and down together with the guide member (29a) guided by 6), it is on the upper side and faces one of the permanent magnets (28) as shown in FIG. 1 (a) before the separating operation. . Therefore, the display body (26) is retracted by suppressing the protrusion by the spring (27).

Reference numeral (30) is an electric wire for connecting to a lightning arrester or the like, and is fitted and fixed by a cap (31) to a drawer metal fitting (20) on the upper part of the closed case (15).

(32) is an electric wire connected to an air switch or the like on the power distribution side, and is electrically connected to the mounting metal fitting (24) in the bush (21). The separating device (9) is shown in FIG.
As shown in Fig. 14, a grounding circuit is constructed with the arrester (2).

Next, the operation of the separating device (9) will be described.

Abnormal voltage such as lightning surge flows to the ground through the gap G and the lightning arrester (2). When the lightning arrester (2) deteriorates and the normal ground voltage of the distribution line cannot be cut off, the conductive plastic (10) heats and melts. The vaporization of the conductive plastic begins immediately before this melting and the arc-extinguishing resin is also heated. When an arc is generated at the fusing point during fusing, the amount of gas generated by the vaporization of the conductive plastic (10) is increased and the pressure around the arc is rapidly increased. Further, when the arc contacts the surface of the arc-extinguishing resin (12) (13), the amount of the arc-extinguishing gas such as H ₂ rapidly increases.

In particular, the arc-extinguishing resin (12) (13) shown in FIG. 1 has a fusing part until the cylindrical second arc-extinguishing resin (13) comes off from the first arc-extinguishing resin (12). Is confined in a narrow space, the contact area of the arc with the arc-extinguishing resin and the heating amount are increased to increase the generation amount of the arc-extinguishing gas, and at the same time, the pressure rise is sharply increased.

The arc is due to the arc extinguishing action of the arc extinguishing gas generated by the heated arc extinguishing resin (12) (13) and the separation of the metal terminals (11) (11) into upper and lower parts by the tension spring (22). By the simultaneous action of the extension of the arc and the pressure increase due to the large amount of gas generated by the vaporization of the conductive plastic (10),
It disappears in a short time. Then, the continuous current due to the normal ground voltage in the charging portion such as the distribution line is cut off.

This disconnection operation causes the lower metal terminal (11) to drop. Therefore, the attractive force does not act between the permanent magnets (28) (29). Then, the display body (26) is projected outward by the spring (27) to display the defect of the lightning arrester (2).

When a large current flows and the inside of the closed case (15) becomes extremely high in pressure, the dangerous part (17) scatters to reduce the internal pressure. Therefore, explosion of the entire closed case (15) can be prevented.

In the above, the specific manufacturing examples of the present invention have been described with reference to FIGS. Since many other embodiments of the present invention are possible, some typical examples will be described.

4 to 8 show modifications of the basic configuration A.

FIG. 4 shows an example in which the conductive plastic (10) is not entirely covered with the first arc extinguishing resin (12) (12) as shown in FIG. Is. If there is this exposed part (10a), the arc continues until it burns. Therefore, the time until separation can be adjusted by this exposure length.

FIG. 5 shows a structure in which the opposing parts of the first arc-extinguishing resin (12) (12) are fitted in such a manner that one is concave and the other is convex, and they are fitted together. The arc extinguishing resin (13) is omitted. This has the advantage of reducing the number of parts.

FIG. 6 shows a structure in which a conductive plastic (10 ') having a structure in which metal terminals (11) (11) at both ends are embedded is adopted instead of the conductive plastic (10) having a female screw shape. Since this structure can be integrally molded in the resin sealing step, there is an advantage that the number of steps is significantly reduced. However, the contact resistance may increase, so the metal terminals (11) and (11) should be knurled at the bonding parts with the conductive plastic (10 '). Then, if the shape shown in FIG. 6 is left unchanged, creeping discharge will occur at the normal ground voltage of the charging section (3).
As shown in FIG. 7, first and second arc extinguishing resin (12)
(12) Cover with (13).

The metal terminals (11) (11) are conductive plastic (10).
Any shape may be used as long as it is electrically connected to (10 ') and relays the electrical connection with the external lead wire or the like, and the shape thereof is not limited to the above-mentioned embodiment.

FIGS. 8 (a) and 8 (b) show a cylindrical gap fitting (14 ') having a circular discharge end and a third end.
It is used in place of the L-shaped gap fitting (14) shown in the figure.

9 and 10 show another embodiment of the display section (18).

FIG. 9 shows the permanent magnet (2) of the display section (18) in the separating device (9) described in FIGS. 1 (a) to (d).
8) When using magnets of the same polarity that exert repulsive force on (29). At this time, the spring (27 ') is replaced with one that biases the display body (26) in the retreat direction, and the permanent magnet (28) fixed to the display body (26) is mounted at a lower position (the tip of the display body). To

FIG. 10 shows the display section (18 ') which is constituted by, for example, a yellow display tube (33) and a transparent closed case (15'). In this case, the display cylinder (33) is fixed to the cup-shaped gap metal fitting (14 ') so as to move together with the lower part of the separated conductive plastic (10), and the upper cap (31') is sealed in black, for example. Cover the upper two-thirds of the case (15 '). In this example,
When the lower part of the conductive plastic (10) is lowered by the disconnecting operation, the display tube (33) can be seen through the transparent sealed case (15 '), and the black color of the cap (31') and the display tube (33). The contrast with the yellow color clearly indicates that the operation has been completed.

Fig. 11 shows that this disconnecting device (9 ') is connected to the electric wire (3
This is an embodiment in which it is directly attached to the tip fitting of the lightning arrester without using 0). In this case, as the closed case (15 ″), a support body (34) extending laterally from the head of the cylindrical body is used. Inside the support body (34), the drawer fitting (20) is connected. The rod-shaped conductor (35) is installed with its one end protruding, and the connection is fixed in the hole of the tip fitting (36) of the lightning arrester (2) in the same manner as in the past by fixing the wire. ) Is inserted and tightened with screws (37) and (37). In this case, since the connection state is different from the case of using electric wires, the support cap (34) is used without using the safety cap that is a dedicated part of the arrester (2). ) A safety cap (38) dedicated to this embodiment, which is screwed to the), is used.
The gap metal fitting (14 ') shown in FIGS. 8 (a) and 8 (b) is used, and a cylindrical silicon resin (39) is arranged between the basic structure A of the present invention and the closed case (15 "). This is to protect the closed case (15 ″) from the arc generated in the gap G.

Although the embodiments described above constitute the present invention as a device for disconnecting a lightning arrester, the present invention can also be used as a device for disconnecting an electric circuit.

〔The invention's effect〕

According to the present invention, by the action of the arc-extinguishing resin that forms a narrow space surrounding the fusing part of the conductive plastic, it becomes possible to surely extinguish the arc during fusing, and the practical use of the disconnecting device using the conductive plastic. Can be achieved.

Further, in the configuration of the present invention sealed in a sealed case, the pair of metal terminals are separated inside the sealed case, and since the sealed case is not separated, the charging part is not exposed even after the disconnecting operation,
Moreover, the electric wire is fixed and does not swing. Therefore, the safety of the equipment can be secured.

[Brief description of drawings]

1 (a) to 1 (d) are views showing a concrete embodiment of the present invention, in which (a) is a sectional view, (b) is a plan view, and (c) is along line NN. Sectional drawing, (d) is the perspective view which looked at the sealed case from the lower side. Figure 2 is Figure 1 (a).
FIG. 3A is a diagram showing the basic configuration A shown in FIG.
(B) is a figure which takes out and shows the gap metal fitting in FIG. 1 (a), (a) is sectional drawing, (b) is a perspective view. 4 to 7 are sectional views showing other examples of the basic structure A of the present invention. 8 (a) and 8 (b) show another embodiment of the gap fitting, in which (a) is a sectional view and (b) is a perspective view. 9 and 10 are sectional views showing a modification of the embodiment shown in FIG. 1 in which the structure of the display section is changed. FIG. 11 is a sectional view showing an embodiment in which the disconnecting device of the present invention is directly attached to the lightning arrester. FIG. 12 is a cross-sectional view of a conventional separating device, FIGS. 13 and 14
The figure is an explanatory view showing a state in which the disconnecting device is attached to the lightning arrester. (10) (10 ') ... Conductive plastic, (11) ... Metal terminal, (12) ... First arc extinguishing resin, (13) ... Second arc extinguishing resin, (14) (14 ′) …… Gap metal fittings, (15) (15 ′) (15 ″) …… Sealed case, (17) …… Dangerous area, (18) (18 ′) …… Display section, (22)… …spring.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toru Takayama 3-15-25 Nakamiya, Asahi-ku, Osaka City, Osaka Prefecture (72) Inventor Yasuyuki Imo, 1-26-1306, Tsukuda, Nishiyodogawa-ku, Osaka City, Osaka Prefecture (56) ) References JP 62-208581 (JP, A) JP 50-122669 (JP, A) JP 59-167982 (JP, A)

Claims (5)

[Claims] 1. A pair of metal terminals to be separated at both ends are fixed, and a conductive plastic whose conductivity is selected so that it melts when a temperature rises to a predetermined value and functions as a heating resistor, and an arc is extinguished by heating. Straddling an arc-extinguishing resin formed of a material that generates a volatile gas and independently surrounding the conductive plastic in each of the two parts divided by fusing, and an arc-extinguishing resin composed of the two members. A cylindrical arc-extinguishing resin that is slidably mounted externally, a discharge gap formed between the pair of metal terminals, and a spring that urges the pair of metal terminals in a direction to disconnect the arc. The fusing part of the conductive plastic that generates heat is placed in the space surrounded by the inner and outer arc-extinguishing resin until the sliding outer cylindrical arc-extinguishing resin is removed from the inner two-member arc-extinguishing resin. Disconnecting device, characterized in that the the like put Flip. 2. A pair of metal terminals to be separated at both ends are fixed, and a conductive plastic whose conductivity is selected so that it melts when a temperature rises to a predetermined value and functions as a heating resistor, and extinguished by heating. Made of a material that generates a volatile gas, and is composed of two members that independently surround the conductive plastic in each of the two parts divided by fusing, and one member slidably covers the outer peripheral surface of the other member. Arc-extinguishing conductive resin having an arc-extinguishing resin having a bottomed cylindrical shape, a discharge gap formed between the pair of metal terminals, and a spring for urging the pair of metal terminals in a direction to separate the pair of metal terminals. The disconnecting device is characterized in that the fusing part of (1) is confined in a space surrounded by two members of arc extinguishing resin. 3. The disconnecting device according to claim 1, which is enclosed in a sealed case. 4. The disconnecting device according to claim 3, further comprising a display portion for displaying that the conductive plastic is melted and the pair of metal terminals are separated from each other outside the hermetically sealed case. 5. The disconnecting device according to claim 3, wherein the hermetically-sealed case is provided with a vulnerable portion that opens to form a window hole when the inside pressure becomes high.