JPH0316194Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a cylindrical cutout, and particularly to a structure of a discharge electrode portion that enables reliable discharge operation even during thunderstorms.

In recent years, the primary side of pole-mounted transformers on high-voltage distribution lines in lightning-struck areas has been equipped with a discharge electrode on the live part of the load side of the cutout, and the discharge electrode is connected to the discharge electrode on the mounting bracket on the ground side. Cylindrical cutouts are used with so-called discharge electrodes (flash angles) facing each other across a discharge gap.

This is to protect the transformer from dielectric breakdown by causing a discharge in the discharge gap when a lightning surge propagates and enters the distribution line, and the discharge current escapes from the mounting bracket to the ground. This is what I did.

By the way, in the above-mentioned cylindrical cutout with a discharge electrode, it is generally not possible to adjust the gap length, and even if it were possible, both discharge electrodes (both charging side and ground side discharge electrodes) making up the discharge gap cannot be adjusted.
Because the shape of the battery does not have a pointed shape, there was a problem in that when a lightning surge invaded, the start of discharge was delayed and sufficient protection could not be provided.

In addition, in the above case, the discharge hole provided in the lower cover is formed small in order to hide the discharge electrode on the live part side, so during thunderstorms, rainwater enters this hole and stagnates inside the hole, so the dielectric There was a problem in that the holes were clogged by rainwater, causing variations in the discharge starting voltage and interfering with discharge.

This invention is a divisional application of Utility Application No. 57-90430.
The original idea relates to a holding device for a current limiting element unit in a cylindrical cutout with a built-in current limiting element, but the present invention relates to the structure of a discharge electrode section and attempts to solve the above-mentioned problems. That is, a charging-side discharge electrode 29 is provided on the side surface of the lower cover 16 of the cut-out main body 1 and has a tip-shaped discharge portion 29b, while a discharge gap G is provided in the arm mounting bracket 5 for the charging-side discharge portion. A ground-side discharge electrode 34 having a tipped shape facing through the electrode is provided so that the gap length can be adjusted so that it can be slid freely in opposing directions and fixed at a desired position, and the lower cover 16 is provided with a slit on the periphery. A water-repellent and insulating discharge guide member 31 having an elastic engagement portion is fitted into the outer opening of a mounting hole provided in the lower cover, and a discharge through hole 31a is provided in the discharge guide member. The discharge electrode 29 is brought into contact with the through hole in such a way that only its pointed discharge portion 29b peeks out into the hole, and the large diameter portion on the base side of the pointed portion engages with the inner end surface of the hole, and further The outlet side opening 31b of the discharge through hole 31a is expanded so that the lower side 31c thereof is inclined downward.

Hereinafter, an embodiment in which the technical concept of the present invention is realized in a cylindrical cutout with a built-in current limiting element will be described with reference to FIGS. 1 and 2.

1 is a main body made of cylindrical porcelain, 2 is an upper lead wire, 3 is a lower lead wire, 4 is a main body support band attached to the center of the main body 1, 5 is a cutout A connected to an armrest 6
7 is a support bolt for connecting the support band 4 and the mounting bracket 5, and 8 is a nut. Further, 9 is a lower fixed electrode fixed in the main body 1, 10 is a fuse tube whose lower contact 11 contacts the lower fixed electrode 9 and is held in the main body 1, 12 is a fuse attached to the fuse tube 10, 13 is a lead wire connecting the lower outlet wire 3 and the lower fixed electrode 9; 14 is a connecting screw; 15 is an arc extinguishing tube housed in the main body 1; 17 is a buffer ring;
Reference numeral 6 denotes a lower cover made of synthetic resin such as polyethylene and fixed to the lower end opening 1a of the main body 1, and the cover 16 is generally cylindrical in its entirety.
A semi-circular storage portion 16b is formed in the upper extension portion 16a so that the current limiting element unit B is arranged concentrically with respect to the inner circumferential wall 1b of the main body 1 when fixed to the lower end opening 1a. An opening 16c is formed in the lower part, and the opening 16c expands downward in a tapered manner.

Reference numeral 16d indicates a discharge electrode attachment hole, one of which communicates with the lower part of the housing portion 16b and the other side opens to the side, and 16e indicates a string attachment hole formed at the periphery of the opening 16c.

Further, B is a semicircular arc-shaped current limiting element unit,
The current limiting element 18 has zinc oxide (ZnO) as its main component,
A small amount of metal oxide such as bismuth oxide (Bi ₂ O ₃ ), antimony oxide (Sb ₂ O ₃ ), etc. is added to this, mixed, and then pressurized with a press at 1200 ml.
The elements 18, which are fired at a high temperature of ~1300° C. and have voltage non-linearity and are formed in a semicircular arc shape, are stacked in two layers, upper and lower, and connected in series. 19 is a contact plate made of aluminum or the like that is interposed between the end faces of the element 18 and ensures contact between the elements; 20 is a metal spraying applied to each of the upper and lower end faces of the element 18; This is an upper terminal connected to the upper end surface 18a, and its lower part is connected to the end surface 18a over its entire surface, and only the center of the upper part protrudes to form a connecting portion 21a. 21b indicates a screw hole. 22 is a lower terminal connected to the lower end surface 18b, and a screw hole 22b is formed in the connecting portion 22a that projects downward. 23 is a metal fitting that fixes the upper terminal 21 so that it does not move during molding, and 24 is a connecting part 21 between both the upper and lower terminals 21 and 22.
EPT, which integrally covers and molds the outer peripheral surfaces of both terminals 21 and 22 and current limiting element 18 when looking through a and 22a;
An insulating member made of tracking-resistant rubber such as EPOM or synthetic resin such as epoxy resin, AAS, ABS, etc. 25 is filled with silicone resin, etc. injected into the recesses 26 formed around both the upper and lower terminals 21 and 22. Indicates the material.

The current limiting element unit B having such a configuration is attached to the main body 1 by the lower cover 16. In other words, the current limiting element unit B is installed by inserting the same unit into the storage part 16b of the lower cover 16 with the front and holding it, and then fixing the lower cover in this state to the lower end opening 1a of the main body 1 with the adhesive 32. It will be done. Note that the connection portion 21a of the upper terminal 21 of the installed current limiting element unit B is connected to the lower fixed electrode 9 by the connection conductor 28,
Further, the charging side discharge electrode 29 inserted through the mounting hole 16d of the lower cover 16 is screwed into the connection part 22a of the lower terminal 22 so that its discharge part 29b faces the discharge part 34a of the earth side discharge electrode, which will be described later. connected. Reference numeral 29a indicates a threaded portion of the discharge electrode 29, and reference numerals 27 and 33 indicate connection screws. 30 is a filling material such as silicone resin injected into the gap of the housing portion 16b to more securely fix the current limiting element unit B, and 31 is a tip-shaped discharge portion 29b located in front of the discharge electrode 29 on the charging side. Through hole 31 for discharge
A is a discharge guide member made of Teflon, silicone resin, or rubber that is surrounded by the member, and the member has elasticity by forming slots on its circumferential surface, and is attached from the outside of the lower cover 16 by taking advantage of this elasticity. It is pushed into the hole 16d and fitted.

The above-mentioned discharge through hole 31a is constructed by constructing the same member 32 with a water-repellent insulating material as described above so that the rainwater that has entered, that is, the rainwater that is a dielectric material does not stagnate in this hole, and also has a discharge through hole. The shape of the hole 31a is expanded so that the lower part 31c on the outlet side opening 31b side is particularly inclined downward so that rainwater inside the hole can be quickly drained out of the hole.

16f indicates a drainage hole communicating with the mounting hole 16d. 35 is a synthetic resin seal plug inserted into the opening 16c of the lower cover 16 by an engaging piece 39;
0 is a connecting string whose one end is passed through the string attachment hole 16e of the lower cover 16 and connected to the same cover 16, and 34 is a ground side where the discharge electrode 29 on the charging side faces the discharge part 29b through the discharge gap G. The discharge part 34a, which is a discharge electrode on the ground side provided at the lower part of the mounting bracket 5, and which faces the discharge part 29b of the discharge electrode on the charging side, has a pointed shape. In other words, when a lightning surge enters both discharge portions 29b and 34a, the electric field is concentrated in the same portion, thereby ensuring that discharge occurs in the discharge gap. Note that the discharge electrode 3
4 has a shaped cross section and can be slid straightly in the front and back direction by means of a guide fitting 41, making it easy to adjust the gap length. Numerals 37 and 38 indicate bolts and nuts for fixing the discharge electrode 34.

If a lightning surge now enters the cutout having the above configuration, this voltage will be applied across the discharge gap G. If the voltage of the lightning surge is larger than the set value of the discharge gap, a discharge occurs in the same discharge gap G, and the surge is caused by the upper lead wire 2 of the cutout - the upper fixed electrode (not particularly shown) - the upper contact of the fuse tube (especially (not shown) - Fuse 12 - Lower contact 9 of fuse tube - Cut-out lower fixed electrode 10 - Connection conductor plate 28 - Upper terminal 21 - Current limiting element 18 - Lower terminal 22 - Charging side discharge electrode 34 - Mounting bracket 5 It is then discharged into the earth.

Further, in this case, the voltage is limited to a low level by the current limiting element 18 interposed in the discharge path, and the follow-on current of the commercial frequency is cut off, thereby protecting the transformer from dielectric breakdown and at the same time preventing the cutout from blowing out the fuse.

Since the present invention is as described above, when a lightning surge enters, the electric field is concentrated in the tip-shaped discharge portions 29b and 34a, so that the discharge in the discharge gap G is reliably performed.

Further, since the discharge electrode 34 on the ground side is provided so as to be slidable in the protruding direction, the gap length can be easily adjusted even when the gap length is to be adjusted in a place with poor footing such as on a pillar.

Further, the discharge guide member 31 provided in the lower cover 16 is made of a water-repellent insulating member, and the discharge through hole 31a formed in the same member has an opening end 31b side thereof and a lower part 31c side thereof. The hole 31 is shaped like a hole that expands downwardly.
Since the rainwater that has entered the chamber can be stagnated, the dielectric rainwater does not cause variations in the discharge starting voltage or prevent discharge, and the discharge can be performed accurately even during thunderstorms. Discharge can be performed. Furthermore, in this invention, the discharge through hole 31a is not provided directly in the lower cover, but is provided in the discharge guide member 31 fitted into the outer opening of the attachment hole 16d provided in the lower cover. , the outer opening of the lower cover into which the discharge guide member is fitted may be formed to have a large diameter;
Therefore, it goes without saying that the operation of inserting and attaching the discharge electrode 29 through this outer opening can be performed easily, but even if the discharge guide member is provided separately from the lower cover, the elastic engagement provided with the slot on the periphery can be easily performed. Since the cover is provided with a section, it can be easily fitted into the cover without being removed by simply pushing it into the opening on the outside side of the cover.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a main part of a cylindrical cutout with a built-in current limiting element, which is an embodiment of the present invention.
Each figure shows a further enlarged and broken sectional view of the main part of FIG. 1. DESCRIPTION OF SYMBOLS 1...Main body, 5...Mounting bracket, 16...Lower cover, 29...Charging side discharge electrode, 29b...Discharge part, 31...Discharge guide member, 31a...Through hole for discharge, 31c... Lower part, 34...Discharge electrode on the ground side, 34a...Discharge part, G...Discharge gap.

Claims (1)

[Scope of utility model registration request] A charging-side discharge electrode 29 having a tip-shaped discharge portion 29b is provided on the side surface of the lower cover 16 of the cutout body 1, and a discharge gap G is connected to the charging-side discharge portion on the arm mounting bracket 5. The lower cover 16 is provided with a ground side discharge electrode 34 having a tipped shape facing each other so as to be able to adjust the gap length, to be able to slide freely in the opposite direction, and to be fixed at a desired position. A water-repellent and insulative discharge guide member 31 with an engaging portion formed therein is fitted into the outer opening of a mounting hole provided in the lower cover, a discharge through hole 31a is provided in the discharge guide member, and the through hole 31a is provided in the discharge guide member. The discharge electrode 29 is brought into contact with the hole such that only its pointed discharge portion 29b peeks out into the hole, and the large diameter portion of the tip portion on the base side engages with the inner end surface of the hole. A structure of a cylindrical cut-out discharge electrode section, characterized in that the outlet side opening 31b of the discharge through hole 31a is expanded so that the lower side 31c thereof is inclined downward.