JPS6326910Y2 - - Google Patents

Description

[Detailed explanation of the invention] In recent years, as part of lightning damage prevention measures for high-voltage distribution lines, cylindrical cutouts with current-limiting elements that have an arrester function or an equivalent mechanism have been used on the primary side of pole-mounted transformers. is being carried out in some areas. These mainly include those in which a current limiting element equivalent to the characteristic elements of an arrester is housed in an expanded porcelain body, and those in which the current limiting element is integrally held in a lower cover fixed to the lower end opening of the porcelain body. All of the above structures use current limiting elements connected in series. In such a case, if importance is placed on the discharge withstand capacity during discharge, the cross-sectional area (current-carrying area) of the element must be at least equal to or larger than the arrester, making it impossible to miniaturize the element. The main body must be expanded, making it unavoidable to increase its size. In addition, if compactness is the main consideration, the latter structure will be used, but in this case, the current limiting element is held at the top of the lower cover that extends into the main body, so the shape of the element is limited, and the cross-sectional area is somewhat small. As the discharge capacity becomes smaller, the discharge withstand performance deteriorates.

This proposal is proposed in view of the above-mentioned two drawbacks, and includes a plurality of current limiting elements that are divided into arc shapes and whose main component is zinc oxide, and a rising part 12a inserted into the main body 1 and a lower end face of the main body. Thick part 12 to match
cylindrical porcelain main body 1;
The lower cover 12 is arranged and fixed in an annular manner in the storage part 12d of the lower cover 12, and the lower cover 12 is fixed to the lower end opening of the lower cover 12. Contact portion 18b ₁ , 1 formed by
8b ₂ and a connecting portion 18c that protrudes upward; a lower portion that includes an arc-shaped conductive portion 20a; contact portions 20b ₁ and 20b ₂ formed to protrude upward at both ends of the conductive portion 20a; and a lead-out portion 20c. A terminal 20 is provided, and one side end surface 14b, 15b, 16 of each of the elements is provided.
b, 17b are the contact portions 20b ₁ , 20 of the lower terminal.
b ₂ respectively to connect each of the elements in parallel to the upper and lower terminals 18 and 20, and connect the connecting portion 18c of the upper terminal 18 to the lower fixed electrode 9 in the main body, and connect the lower The lead-out portion 20c of the terminal 20 is connected to the discharge electrode 24, and the discharge portion 24a of the discharge electrode is opposed to the flash angle of the mounting bracket through the discharge gap, and the same contact portion is connected to the contact portion of both the upper and lower terminals. This device is characterized by interposing a coil spring 22 that presses against the end face of the element.

Examples of the present invention will be described below. Reference numeral 1 denotes a cylindrical porcelain main body, with an upper lead line 2 provided at the upper part and a lower lead line 3 provided at the lower side. Reference numeral 4 denotes a support band at the center of the main body, which is connected to a mounting bracket 5 and attached to an armrest 6 of a telephone pole. Reference numeral 7 denotes a fuse tube, which is held in the cutout body with a fuse 8 attached thereto. Reference numeral 9 denotes a cut-out lower fixed electrode, and a lead portion 10 of a lower lead wire is connected to the cut-out electrode by a screw 11. Reference numeral 12 designates a lower cover made of synthetic resin such as polyethylene that is fixed to the lower end opening 1a with an adhesive 13, and has an upper rising portion 12a that is located inside the main body when fixed.
Large diameter and thick wall portion 12b located at the lower end surface of the main body
and an expanded portion 12c at the lower end, and an annular and groove-shaped storage portion 12d for holding a current limiting element and the like is formed in the thick portion. Current limiting elements 14, 15, 1
6 and 17 are sintered bodies mainly composed of zinc oxide (ZnO), which has characteristics such as voltage non-linearity and non-following current, and are formed into an arc shape and divided into four parts to form the annular shape of the lower cover. The elements are pushed into the molded housing part 12d from above and arranged in an annular shape to hold them. In this case, the elements are connected in parallel with their side end surfaces to the upper terminal 18 and the lower terminal 20. ing. In other words, among the annularly arranged current limiting elements, a semicircular arc-shaped upper terminal 18 is provided at a slightly distant position above the elements 14 and 15, and both ends of the conductive part 18a have a cross-sectional shape that protrudes downward in the vertical direction. The contact portions 18b ₁ and 18b ₂ are fixed with studs 19, and the contact portions 18b ₁ and 18b ₂ are attached to one side end surface 14a, 15a, 16a, 17a of each element.
is connected to. Reference numeral 18c denotes an elastic connecting portion fixed to the conductive portion 18a at one end together with the contact portion _18b2 by a stud 19. Reference numeral 20 denotes a semicircular arc-shaped lower terminal, with a conductive part 20a provided at a slightly distant position below the elements 16 and 17, and contact parts 20b ₁ and 20b fixed to both ends of the conductive part with studs 21. ₂
and a lead-out portion 20c, and the contact portions 20b ₁ , 2
0b ₂ is the other side end surface 14b, 15b of each element,
16b and 17b, respectively. The side end faces of the element are sprayed with metal such as aluminum or silver, and coil springs 22 are interposed at the contact parts of both the upper and lower terminals to press the contact parts against the end faces of the element to ensure good contact. I try to keep it.

If such a state is shown in circuit form, as shown in FIG. 8, each element is connected in parallel to the upper and lower terminals. In the figure, i ₁₄ , i ₁₅ , i ₁₆ , and i ₁₇ indicate discharge currents that flow in branches to each element.

After connecting and assembling 23 as above, the storage part 12
d is a silicone resin filler injected from above into the gap formed between the elements to seal it; 24 is a discharge electrode made of a screw provided at the lead-out portion 20c of the lower terminal; The mounting bracket 5 has a discharging portion 24a at the tip that slightly protrudes from the discharging hole 12e when fixed to the opening 19 and is grounded.
A discharge gap G is formed in the direction with respect to the flash angle 5a. In addition, when fixing the lower cover, the connecting part 18c formed with the notch guide part 18c' is connected to the holding nut 2 of the lower lead wire 3 connected to the lower fixed electrode 9.
It is elastically connected to 5. 26 is a filling material such as silicone resin that covers the rear part of the discharge electrode, that is, the inner surface of the lower cover, and 27 is the expanded portion 12 of the lower cover.
c is a synthetic resin seal plug inserted and held by an engaging member 28; 29 is a coil spring that urges the engaging member to spring out so that the engaging member comes into elastic contact with the seal plug; 30 is a connection Show the string.

In the above structure, when an abnormal voltage such as a lightning impulse enters, a discharge gap G is formed between the discharge electrode of the lower terminal and the flash angle 5a of the grounded mounting bracket.
When the same voltage is applied to and exceeds the set value, the discharge gap flashes and the abnormal voltage is passed through the lower fixed electrode 9 - lead part 10 - upper terminal connection part 18c - upper terminal 18 - current limiting. Elements 14, 15,
16, 17 - lower terminal 20 - lead-out part 20c - discharge electrode 24 - discharge gap G - flash angle 5a - transformer that is safely discharged to the ground via the mounting bracket 5 and connected to the lower lead wire of the cutout Of course, this abnormal voltage is not applied to the cutout, which ensures reliable protection, and since no follow-on current flows, the cutout fuse does not blow due to abnormal voltage. Note that under normal circumstances, the current limiting element is electrically insulated with a discharge gap formed in series with the current limiting element.

Furthermore, in the above embodiment, an arc-shaped current limiting element divided into four parts is used, but the technical idea of the present invention is not limited to this number, but two or more, that is, a plurality of arc-shaped current limiting elements. If these elements are arranged in a ring and each element is connected in parallel at the same time, the discharge capacity can be expected to increase, and it can be easily held in the annular storage part formed outside the main body of the lower cover. This naturally falls within the technical scope of the present case.

This project consists of the above-mentioned configuration, in which the current limiting elements are arranged in a ring shape in the storage part located outside the main body of the synthetic resin lower cover fixed to the lower end opening of the cylindrical porcelain body, and the same elements are connected in parallel. Then, the upper terminal was connected to the lower fixed electrode of the cutout, and the lower terminal was connected to the discharge electrode, and the connected electrodes were made to face the flash angle of the mounting bracket, forming a discharge gap. As a result, even if the lightning energy is large and the discharge current is also large, the discharge current can be distributed (shunted) to each current limiting element, so the current flowing through each element is reduced, allowing safe discharge operation. can do. In addition, since the cross-sectional area (current-carrying area) of the element can be reduced, it can be easily held in the annular storage part of the lower cover located outside the main body, and there is no need to expand the cover particularly much, which is the current situation. It can be implemented in the same size as the porcelain body, and the conventional porcelain body can be used as is without changing the shape.It is characterized not only by its electrical performance such as discharge capacity but also by being able to make the overall shape smaller. be.

In addition, since the current limiting element is formed in an arc shape and the upper and lower terminals are connected to the side end faces of the element, the creepage distance between the upper and lower terminals becomes long, which of course prevents an accident of external shorting of the element. It also has features such as being insulated by the discharge gap and having a long service life.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a main part of a cylindrical cutout with a current limiting element showing an embodiment of the present invention, Fig. 2 is a bottom view showing the assembled state of the current limiting element, and Fig. 3 is a line E-E in Fig. 2. The cross-sectional view, Figure 4, is also A in Figure 2.
-A sectional view, Figure 5 is also B- in Figure 2.
B sectional view, Figure 6 is also C-C in Figure 2.
7 is a sectional view taken along the line DD in FIG. 2, and FIG. 8 is an equivalent circuit diagram of FIGS. 2 to 3. 1... Cylindrical porcelain body, 1a... Lower end opening,
5... Mounting bracket, 5a... Flash angle, 9... Lower fixed electrode, 12... Lower cover, 12d... Storage section, 14, 15, 16, 17... Current limiting element, 14
a, 15a, 16a, 17a... side end surface, 14
b, 15b, 16b, 17b... side end surface, 18
...Top terminal, 20...Bottom terminal, 24...Discharge electrode, G...Discharge gap.

Claims (1)

[Scope of utility model registration request] A plurality of current-limiting elements made of zinc oxide as a main component and divided into arc shapes, a rising portion 12a inserted into the main body 1, and a thick wall portion 12b engaging with the lower end surface of the main body.
and a synthetic resin lower cover 12 having an arc-shaped housing portion 12d formed in the thick wall portion into which the current limiting element is inserted. 12, the current limiting element is arranged and fixed in an annular manner in the housing portion 12d of the lower cover 12, and a contact portion 18b ₁ is formed by separately bending the arc-shaped conductive portion a and its ends downward. 18
b ₂ and an upper terminal 18 having an upwardly protruding connecting portion 18c; and a lower portion having an arcuate conductive portion 20a, contact portions 20b ₁ and 20b ₂ formed upwardly protruding at both ends thereof, and a lead-out portion 20c. A terminal 20 is provided, and one side end surface 14b, 15b, 16b,
17b are connected to the contact portions 20b ₁ and 20b ₂ of the lower terminal, respectively, to connect the respective elements in parallel to the upper and lower terminals 18 and 20, and the connecting portion 18c of the upper terminal 18 is connected to the contact portion 20b 1 and 20b 2 of the lower terminal. Connected to the lower fixed electrode 9 and the lead-out portion 20 of the lower terminal 20
c is connected to the discharge electrode 24, and the discharge part 24a of the discharge electrode is opposed to the flash angle of the mounting bracket through the discharge gap, and the contact part of both the upper and lower terminals is pressed against the element end surface. A cylindrical cutout with a current limiting element characterized by interposing a coil spring 22.