JPH05152110A - Arrester - Google Patents

Abstract

PURPOSE:To eliminate posibility in a destruction due to an excessive increase of an internal pressure of an insulator by accurately destructing a pressure- releasing plate when an arc generates within the insulator. CONSTITUTION:A plate-like gunpowder chamber 9 in which a gunpowder is enclosed is arranged inside a pressure-releasing plate 5 so as to put on the pressure-releasing plate 5 like a lid, and a ring-like detecting electrode 10 is fitted on the grounding electrode side to an electrode 31 on the high-voltage side of an upper part of an arrester element 2 with insulating fittings. Leads 21, 22 are led out from this detecting electrode 10 and a conductor on the high- voltage side, and these tips are embedded in the gunpowder and the both tips are arranged at a small space. As the electrodes 31, 32 on the high-voltage and grounding sides are bridged by an arc generated within the insulator through the detecting electrode 10, potential difference between the detecting electrode 10 and the electrode 31 on the high-voltage side is caused. Both the tips in the gunpowder are discharged due to this potential difference to initiate the gunpowder, and the pressure-releasing plate 5 is destructed by explosive powder of the gunpowder to restrict an increase in pressure within the insulator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightning arrester for protecting electric equipment installed in a power system from a high voltage surge caused by lightning.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view of a conventional lightning arrester. In this figure, a lightning arrester element 2 having a plurality of elements stacked in a cylindrical insulator 1 is housed by being sandwiched between electrodes 31 and 32. The spring 33 applies a predetermined pressure stably without being affected by the temperature change. The inside of the insulator 1 in which the lightning protection element 2 is housed is filled with dry air, dry nitrogen or the like so that the lightning protection element 2 does not deteriorate in characteristics due to moisture absorption. In order to make the inside of the insulator 1 airtight, the opening at the top of the insulator 1 is covered with a pressure release plate 5. By the way, the total height of this arrester is about 1 m.

A metal lid 4 is provided on the top of the insulator 1 and is attached to the insulator 1 with bolts 7. A packing (not shown) is provided on the surface of the lid 4 that comes into contact with the insulator to maintain airtightness. Further, the pressure release plate 5 described above is attached to the outside of the lid 4 by a mounting plate which is not attached to the bolt 51, and the contact surface between the lid 4 and the pressure release plate 5 is also provided with packing (not shown) to provide an airtight seal. Is held. The pressure release plate 5 is formed by coating a thin copper plate of about 0.1 mm with epoxy resin on one surface.

The lid 4 is provided with through holes on both sides of the central portion of the drawing, and in that portion, the pressure release plate 5 is in direct contact with the dry gas in the insulator 1. The upper portion of the spring 33 is supported by the cap 34, but the cap 3
The rectangular cross section above 4 is part of lid 4. The upper electrode 31 and the lower electrode 32 of the lightning protection element 2 are not shown in the figure.
The lightning arrester 2 is connected by a plurality of insulating bolts and is supported by the insulating bolts so that the lightning protection element 2 does not collapse even if the tightening force is insufficient.

The terminal 80 on the high voltage side is connected to the high voltage wiring by a lead (not shown), and is connected to the electrode 31 from the terminal 80 through a copper plate (not shown) provided in parallel with the cover 6, the bolt 7, the lid 4 and the spring 33. High voltage is being applied. Further, in the lower part, the ground lead 83 is mounted by being sandwiched between the terminal 81 and the terminal plate 82, and the terminal 81 is electrically connected to the electrode 32 via the mounting metal fitting 35. In this way, the lightning arrester element 2 includes the high voltage side electrode 31 and the ground side electrode 32.
A high voltage is applied between them.

When the applied voltage is a steady voltage, the lightning arrester element 2 has a high resistance and only a small leak current flows. On the other hand, when a lightning surge enters the high-voltage wiring and the voltage exceeds the limit voltage determined by the characteristics of this arrester, the resistance value drastically decreases and a large current flows, limiting the rise in the voltage of the system and installing it in the vicinity. Protects electrical equipment such as transformers and circuit breakers that are present from lightning surges.

The pressure relief plate 5 is provided so that when dielectric breakdown occurs for some reason between the upper and lower electrodes 31 and 32 and a continuous arc is generated, the pressure inside the insulator 1 increases and the insulator 1 is destroyed. This is to prevent The arc is generated when the lightning arrester element 2 breaks down and develops into an arc when a debt exceeding the protection capability of the lightning arrester is given, and the pressure relief plate 5 breaks down due to the pressure increase due to the occurrence of such arc. The high-pressure gas generated by the arc is discharged to the outside through the pressure release hole 61 provided in the cover 6 on the left side of the cover 6 in the figure, and the rise of the pressure in the insulator 1 is limited.
An arc horn 62 is provided at a position where the high pressure gas is discharged, and the high pressure gas containing ions generated by the internal arc facilitates dielectric breakdown between the arc horn and the ground, resulting in the insulator 1 The arc generated inside moves between the arc horn 62 and the ground, and has a function of stopping the pressure increase in the insulator 1.

[0008]

When an arc occurs inside the insulator, if the pressure-release plate 5 is surely destroyed, the pressure rise in the insulator 1 is limited by the phenomenon as described above and the insulator 1 is destroyed. There is no such thing. However, if the release of the pressure-release plate 5 is delayed for some reason, there is a possibility that an accident may occur in which the pressure rise becomes excessive and the insulator 1 is damaged.

An object of the present invention is to solve such a problem and to reliably destroy the pressure-release plate when an arc occurs inside the insulator to eliminate the possibility of damage to the insulator.

[0010]

In order to solve the above problems, according to the present invention, a lightning arrester element sandwiched between a high voltage side electrode and a ground side electrode is a gas-sealed cylindrical insulator. In a lightning arrester that is provided with a pressure relief plate that covers the high-pressure side opening of the insulator, an explosive chamber in which explosive is enclosed inside the pressure relief plate and the pressure relief plate is part of the wall surface, and an insulating fixture. Is provided on the ground side of the high-voltage side electrode to provide a detection electrode made of a ring-shaped conductor that surrounds the lightning protection element, and the explosive is detonated by a voltage induced between the detection electrode and the high-voltage side electrode. In addition, one end is electrically connected to the high-voltage side conductor and the other end is inserted into the explosive, and the other end is electrically connected to the detection electrode and the other end is inserted into the explosive. Provide the inserted insulation-coated leads on the sensing electrode side The respective tips in gunpowder between the detection electrode side of the lead and the high pressure side of the lead shall become disposed at predetermined intervals.

[0011]

In the structure of the present invention, a ring-shaped ring surrounding the lightning arrester is provided so that the explosive plate is destroyed when the explosive powder explodes by providing an explosive chamber inside the pressure-release plate and having the pressure-release plate as a part of the wall surface. If the detection electrode is provided on the ground side of the electrode on the high voltage side and attached to the electrode on the high voltage side with an insulative fitting, the detection electrode is in a potential floating state. Therefore, when an arc is generated between the high voltage side electrode and the ground side electrode, the arc passes through the detection electrode, and a potential difference is generated between the high voltage side electrode and the detection electrode. When this potential difference is introduced to the explosive and used for detonation, the explosive explodes immediately when an arc occurs and the pressure relief plate is destroyed. In addition, both ends of the two leads, one having one end electrically connected to a high-voltage side conductor such as an electrode on the high-voltage side and the other having one end electrically connected to the detection electrode, are connected to the above-mentioned explosive powder. When the arc is generated, the
An electric discharge is generated between the tips of the leads of the book to cause an explosion.

[0012]

EXAMPLES The present invention will be described below based on examples.
1 is a partially enlarged sectional view showing an embodiment of the present invention,
The same members as those in FIG. 3 are denoted by the same reference numerals and detailed description thereof will be omitted. Further, the parts of FIG. 1 which are not shown are shown in FIG.
Is the same as. In FIG. 1, an explosive chamber 9 is provided in contact with the lower side of the pressure release plate 5 in the drawing. The explosive chamber 9 is attached to the lid 4. On the other hand, the detection electrode 10 is attached to the lower portion of the electrode 31 which is on the ground side by the insulating fixture 11. Since the detection electrode 10 has a ring shape that surrounds the lightning protection element 2 and is insulated from the electrode 31 and is not connected to any conductor, it is in a potential floating state.

One end of a lead 22 is connected to the detection electrode 10 and the other end is inserted into the explosive chamber 9. Further, a lead 21 is connected to the lid 4 and this is also inserted into the explosive powder 9. The leads 21 and 22 are covered with an insulating coating (not shown) so that dielectric breakdown does not occur between the leads 21 and 22 except in the explosive chamber 9. However, since the periphery of the lead 21 has the same potential, it is not always necessary to insulate the lead 21 if one lead 22 is covered and insulated.

FIG. 2 is an enlarged sectional view of the explosive chamber 9. In this figure, the explosive chamber 9 is dish-shaped and the upper part is a pressure release plate 5.
It is placed with the lid on. Gunpowder chamber 9 has arms 91
It is attached to the lid 4 as shown in FIG. An explosive powder 90 is enclosed in the explosive chamber 9, and the respective end portions of the leads 21, 22 are embedded in the explosive powder 90, and the respective distal ends are arranged with a small gap G therebetween.

When the electrodes 31 and 32 are dielectrically broken down and bridged by an arc, there is a detection electrode 10 in a potential floating state in the path of this arc, so that the arc passes through the detection electrode 10. As a result, a bridge is formed between the electrodes 31 and 32. As a result, a potential difference is generated between the electrode 31 and the detection electrode 10, and this voltage causes the lead 2 in the explosive 90 to
An electric discharge is generated between the tips of the Nos. 1 and 22 and is detonated to explode the powder. Since the dish-shaped portion of the explosive chamber 9 has a far greater strength than the pressure release plate 5, the explosion of the explosive 90 breaks the pressure release plate 5.

When the pressure-release plate 5 is broken, the insulator 1 is used as described above.
As a result, the arc generated inside moves to the external arc horn 62 and the arc inside the insulator 1 disappears. Arc horn 6
The arc continues inside the insulator 1 until it shifts to 2, but at that time as well, the pressure relief plate 5 has already been broken, so an excessive pressure rise does not occur. Further, since the pressure rise in the insulator 1 is not required to break the pressure relief plate 5 and is caused by the arc which is a phenomenon in the preceding stage, the pressure rise can be surely limited. The arrangement of the leads 21 and 22 and the connection positions with the electrodes can be carried out in various ways other than those shown in the figure. FIG. 1 shows only one example, and a structure other than this figure shows the invention. It is acceptable as long as it does not defeat the purpose. Further, the structure and mounting position of the explosive chamber 9 are not limited to those shown in FIGS.

[0017]

As described above, according to the present invention, a dish-shaped explosive chamber containing explosives is disposed inside the pressure-release plate so as to be covered with the pressure-release plate so that the pressure-release plate is broken by the explosion of the explosive. On the other hand, a ring-shaped detection electrode is attached to the ground electrode side of the high voltage side electrode with an insulating fitting. Since this detection electrode is in a floating state in terms of potential, the arc generated between the high voltage side electrode and the ground side electrode passes through this detection electrode. Therefore, a potential difference is generated between the high voltage side electrode and the detection electrode. By introducing this potential difference into the aforementioned explosive and using it for detonation, it is possible to reliably destroy the pressure-release plate due to the occurrence of an arc, so the pressure rise in the insulator due to the arc becomes excessive and the insulator is damaged. This has the effect of eliminating the possibility of accidents, and also has the effect of preventing the ripple effect of broken pieces of insulators damaging electrical equipment installed in the vicinity. Also, pull out one lead from the electrode on the high voltage side or a conductor with the same potential as this,
When the leads of a book are pulled out and their tips are introduced into the aforementioned explosive chamber and embedded in the explosive, the tips of the two leads are arranged with a small space between them, and they occur between the conductor on the high voltage side and the detection electrode. Since a discharge is generated between the tips of the leads due to the potential difference, it is possible to reliably initiate the detonation.

[Brief description of drawings]

FIG. 1 is a partially enlarged sectional view of a lightning arrester showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of the explosive chamber shown in FIG.

FIG. 3 is a sectional view of a conventional lightning arrester.

[Explanation of Codes] 1 Insulator 2 Lightning element 5 Pressure release plate 10 Detection electrode 11 Fixture 21 Lead 22 Lead 31 Electrode 32 Electrode 9 Explosive chamber 90 Explosive

Claims (2)

[Claims] 1. A lightning arrester sandwiched between a high-voltage side electrode and a grounding side electrode is housed in a gas-sealed cylindrical insulator, and a pressure-release plate is provided to cover an opening on the high-pressure side of the insulator. In the lightning arrester formed as described above, an explosive chamber in which explosive is enclosed inside the pressure-releasing plate and the pressure-releasing plate is a part of the wall surface, and a ring which is attached to the ground side of the high-voltage side electrode by an insulating fixture and goes around the lightning arrester A lightning arrester characterized in that a detection electrode made of a conductor is provided, and the explosive is detonated by a voltage induced between the detection electrode and the electrode on the high voltage side. 2. A high-voltage side lead having one end electrically connected to a high-voltage side conductor and the other end inserted in a powder, and one end electrically connected to a detection electrode and the other end into the powder. Insulation-coated leads on the side of the detection electrode that are inserted are provided, and the tips of the leads on the side of the detection electrode and the leads on the high-voltage side in the explosive are arranged at a predetermined interval. The lightning arrester according to claim 1.