JPH0157476B2 - - Google Patents

Description

[Detailed Description of the Invention] a. Technical Field of the Invention The present invention relates to a lightning protection unit that is used by being attached to various power distribution equipment such as a switch or a cutout, and in particular, it relates to a lightning protection unit that is used by being attached to various power distribution equipment such as a switch or a cutout, and in particular, it relates to a lightning protection unit that is used by being attached to various power distribution equipment such as a normal switch or a cutout. This invention relates to an improvement of a lightning protection unit that houses a resistance element (hereinafter referred to as a characteristic element) with excellent nonlinear characteristics.

b. Prior art and its disadvantages Conventionally, lightning protection units installed in various power distribution equipment maintain the lightning impulse discharge starting voltage value as low as possible within the range that can ensure self-restorability, and when no surges such as induced lightning occur. is a simple gap that can stably maintain the normal ground voltage of the 6.6KV distribution line, a zinc oxide resistance element, etc. that maintains the limit voltage as low as possible within the range that can ensure self-restorability, and has excellent nonlinear characteristics. was mounted inside a porcelain container or an insulating case made of organic insulating material.

In general, power distribution lines are spread over a wide variety of areas with pole transformers and various devices distributed, and the lightning protection units built into these devices ensure the insulation level of the lines and the reliability and stability of the distribution lines. Even though the equipment has performance that fully satisfies the standards from the standpoint of product safety, it may be damaged by induced lightning or lightning strikes. There was a risk that it might have been damaged.

Conventionally, measures to prevent this have been taken such as increasing the inner diameter or thickening of the porcelain container or organic insulating case.

At the same time, in the case of organic insulating cases, reinforced plastic (FRP) or epoxy resin is often used because materials with excellent electrical, mechanical properties, and weather resistance are required. It had the advantage of being extremely easy to use.

However, if the insulating case is made of only organic insulators such as reinforced plastics as mentioned above, there is a possibility that surface leakage current due to the normal ground voltage of the 6.6KV distribution line will flow along the inner surface of the insulating case. Once it becomes dirty or scratched, its leakage current increases and the surface becomes carbonized, causing a so-called tracking phenomenon, which has the disadvantage of leading to grounding accidents on power distribution lines.

On the other hand, in order to prevent such tracking phenomenon, it is conceivable to construct the insulating case containing the series gap and characteristic elements only from inorganic materials such as porcelain and ceramics, but inorganic materials are extremely vulnerable to impact internal pressure and will scatter. Although it is easy to use, it also has the disadvantage that the process for attaching it to the terminal fitting is complicated.

c. Object of the present invention The object of the present invention is to solve the above-mentioned conventional drawbacks, and to provide a lightning protection unit suitable for use inside a switch or a cutout.

d Embodiment FIG. 1 shows a cross section of the left half of the lightning protection unit according to the present invention in order to show the internal structure in detail. In the figure, reference numeral 1 denotes an insulating case made of an organic insulator, such as reinforced plastic (so-called FRP) such as epoxy resin or polyester resin mixed with glass fiber. 2 is a simple gap that maintains the normal ground voltage stably and discharges when an abnormal surge occurs. 3 is a characteristic element that is connected in series with this simple gap 2 and is incorporated into the insulating case 1, and this characteristic element 3 is made of, for example, a resistance element with excellent non-linear characteristics made of zinc oxide (ZnO) or the like. be done. That is, when an abnormal voltage enters, that high voltage is applied between the charging side terminal fitting 7 and the grounding side terminal fitting 6, and the simple gap, which has been in an insulating state until now, is discharged, and the abnormal voltage becomes a characteristic element. 3 Discharged to the ground via the ground side terminal fitting. In this case, the gap 2 exhibits an extremely high insulation resistance until it is discharged due to an abnormal voltage. In addition, this characteristic element is non-following current, reliably blocks following current, and does not suffer from serious deterioration. 4 is a thermosetting resin interposed between the insulating case 1 and the characteristic element 3, and is a resin material such as epoxy resin or silicone resin.

5 is a connecting conductor for connecting the series gap 2 and the characteristic element 3 in series, and the series connected gap 2, the connecting conductor 5 and the characteristic element 3 are connected to the ground side terminal fitting 6 and the charging side terminal fitting 7. It is held between the two with a spring 8 interposed therebetween.

In the above configuration, according to the present invention, an inner wall portion 9 made of an inorganic material such as porcelain or ceramic is attached to the inner surface of the insulating case 1 made of the organic insulating material, for example, by adhesive or other attachment means.

In the embodiment, an inner wall portion 9 is attached to the inner surface of the insulating case 1 facing the series gap 2.

Leakage current due to the normal ground voltage flows along the inner surface of the inner wall portion 9, but since it is an inorganic material, the insulation resistance is high and there is little deterioration, and there is no fear that it will increase over time.

Therefore, the inner wall portion 9 can be provided on the entire inner surface of the insulating case 1 or at appropriate locations so as to prevent the so-called tracking phenomenon from occurring on the inner surface of the insulating case 1 made of an organic insulator.

Further, when the above lightning protection unit is used in a cutout, the above lightning protection unit may be installed so as to be connected in series with the fuse. As described above, a lightning protection unit suitable for use in switches, cutouts, etc. is realized.

FIG. 2 is an explanatory diagram showing another embodiment of the lightning protection unit according to the present invention. In the figure, the same parts as in FIG. 1 are given the same reference numerals. In the lightning protection unit of this embodiment, an inner wall portion 9 is provided over substantially the entire area of the insulating case 1.

By attaching the ground side terminal fittings 6 and the charging side terminal fittings 7 to both ends of the inner wall portion 9, the inside of the insulating case becomes airtight.

FIG. 3 is a side sectional view showing the structure of a cutout using the lightning protection unit shown in FIG. 1.

In the figure, 10 is a porcelain body, 11 is a fuse tube, 12a and 12b are movable contacts of the fuse tube 11, 13a and 13b are wire connection terminals, 14 is a porcelain lid, and 15 is a lightning protection unit.
16 is a fuse attached to the fuse tube 11, 17
a and 17b are upper and lower arc extinguishing chambers, 18a
and 18b are fixed contacts; 19 is the terminal fitting 7;
and a connecting fitting for connecting the fixed contact 18b, 20,
Reference numeral 21 denotes a grounding terminal and a grounding metal fitting connected to the terminal fitting 6, 22 a buffer rubber disposed between the porcelain main body 10 and the grounding side metal fitting 21, and 23 a support metal fitting attached to the upper side of the porcelain main body 10. It is.

A high-voltage underline wire (not shown) for supplying high-voltage current is connected to the wire connection terminal 13a, an input terminal of a load such as a transformer is connected to the connection terminal 13b, and the ground side terminal 20 is grounded.

Therefore, the high voltage current normally supplied from the high voltage underline is connected to the connecting terminal 13a, the fixed contact 18a, the movable contact 12a, the fuse tube 16, the movable contact 12b,
It is supplied to the load via the fixed contact 18b and the connection terminal 13b.

When a lightning surge current is applied to the high-voltage underline, the lightning surge current flows through the connection terminal 13a, fixed contact 18a, movable contact 12a, fuse tube 11,
Fuse 16, movable contact 12b, fixed contact 18
b, connection fitting 7, series gap 2, characteristic element 3,
It is connected to the ground via the terminal fitting 6 and the ground side terminal 20.

Therefore, the load can avoid being directly hit by lightning surge current.

e Effects of the present invention As explained above, the lightning protection unit of the present invention has an inner wall portion made of an inorganic material on the inner surface of an insulating case made of an organic insulator that houses the series gap and characteristic elements therein. Therefore, it is strong against internal impact pressure, the insulation case does not scatter, there is no risk of burning out of the organic insulators that make up the insulation case due to the so-called tracking phenomenon, and it is easy to process with terminal fittings, making it airtight. Since the structure can be maintained, there is no deterioration over time, and it has excellent reliability, and has the advantage that it can be applied to switches, cutouts, etc. to obtain a suitable lightning protection unit.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view of a lightning protection unit according to one embodiment of the present invention, FIG. FIG. 3 is a side sectional view showing the configuration of a cutout. 1... Insulating case made of organic insulator, 2...
Series gap, 26a, 26b... Packing, 3
...Characteristic element, 9...Inner wall part.

Claims (1)

[Scope of Claims] 1. A lightning protection unit comprising a series gap and characteristic elements inside an insulating case made of an organic insulator, characterized in that an inner wall part made of an inorganic material is provided on the inner surface of the insulating case. unit. 2. The lightning protection unit according to claim 1, wherein the insulating case is made of reinforced plastic, and the inner wall part is made of porcelain or ceramic. 3. The lightning protection device according to claim 1, wherein the insulating case has the inner wall part provided on a part of the inner surface, and the other part of the inner surface is filled with a resin material. unit. 4. The insulating case is provided with the inner wall portion over almost the entire area of the inner surface, and gaskets are arranged at both ends of the inner wall portion, and the interior can be made airtight by attaching terminal fittings to both ends of the insulating case. A lightning protection unit according to claim 1, characterized in that: