JP6995248B1 - Protective shutter and closed switchboard - Google Patents

Abstract

The protective shutter (4) disclosed in the present application is the main circuit of the panel side housing (8) when the circuit breaker (9) in the closed switchboard (1) is pulled out with respect to the panel side housing (8). A protective shutter (4) that covers the terminal (3) with respect to the insulating wall portion (42) and the insulating wall portion (42) facing the main circuit terminal (3) when covering the main circuit terminal (3). It is characterized in that it is configured to include a metal plate portion (41) arranged with a gap (4s) on the side away from the main circuit terminal (3).

Description

The present application relates to protective shutters and closed switchboards.

In a closed switchboard, when the circuit breaker is pulled out from the board side housing for inspection, etc., the charging part normally housed inside is exposed to the outside, and in order to protect the workers who enter the board. The main circuit terminal, which is the charging unit, is partitioned and covered with a structure such as a shutter. At that time, by using a composite material provided with a grounding metal that allows leakage current to escape on the outside of the insulation for shortening the insulation distance, a shutter device that attempts to achieve both shortening of the insulation distance and suppression of leakage current is available. It has been proposed (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 4-190607 (Page 6, upper left column, line 2 to page 6, upper right column, line 5, line 11)

However, since the ground metal, which is a composite material with the insulator, serves as a back electrode for the insulator, the effect of shortening the insulation distance from the main circuit terminal cannot be exhibited, and the closed switchboard to be mounted cannot exert the effect. It was difficult to reduce the size.

The present application discloses a technique for solving the above-mentioned problems, and an object thereof is to obtain a protective shutter capable of shortening the insulation distance from the main circuit terminal and forming a compact and highly reliable closed switchboard. And.

The protective shutter disclosed in the present application is a protective shutter that covers the main circuit terminal of the panel-side housing when the circuit breaker in the closed switchboard is pulled out with respect to the panel-side housing, and the main circuit terminal is covered. It is provided with an insulating wall portion facing the main circuit terminal when covering, and a metal plate portion arranged with a gap on the side away from the main circuit terminal with respect to the insulating wall portion, and the metal plate portion has a cross-sectional shape. Is formed of a bow shape, and is characterized in that the insulating wall portion is formed of a flexible sheet material stretched from one end to the other end of the bow shape .

According to the protective shutter disclosed in the present application, the metal plate portion is provided with a gap in the insulating wall portion, so that the insulation distance can be shortened and the leakage current can be suppressed in a compact size. A highly reliable closed switchboard can be formed.

1A and 1B are a cross-sectional view shown together with a main circuit terminal and an enlarged cross-sectional view of the protective shutter portion for explaining the configuration of the protective shutter according to the first embodiment. It is a perspective view which cut out a part of the circuit breaker chamber part for showing the structure of the protective shutter which concerns on Embodiment 1 and the closed switchboard equipped with the protective shutter. 3A and 3B are a state in which the circuit breaker is pulled out and a connection position for explaining the operation of the protective shutter according to the first embodiment and the protective shutter in the closed switchboard equipped with the protective shutter, respectively. It is a perspective view which shows the state. 4A and 4B are a cross-sectional view shown together with the main circuit terminal and an enlarged cross-sectional view of the protective shutter portion for explaining the configuration of the protective shutter according to the second embodiment.

Embodiment 1.
1 to 3 are for explaining the configuration of the protective shutter according to the first embodiment and the closed switchboard using the protective shutter, and FIG. 1 is B in FIG. 2 for explaining the configuration of the protective shutter. -A cross-sectional view corresponding to line B, FIG. 1A is a cross-sectional view showing a state in which the protective shutter covers the main circuit terminal (when the circuit breaker is pulled out) together with the main circuit terminal, and FIG. 1B is a protective shutter portion in FIG. 1A. It is a cross-sectional view which is enlarged and rotated by 90 ° in the counterclockwise direction.

Further, FIG. 2 is a perspective view of the circuit breaker chamber portion in which the main circuit terminal portion of a certain phase is cut out by the BB line in a state where the circuit breaker is pulled out in the closed switchboard equipped with the protective shutter. 3A and 3B are perspective views for explaining the operation of the protective shutter in the closed switchboard, FIG. 3A is a perspective view corresponding to FIG. 2 with the circuit breaker pulled out, and FIG. 3B shows the circuit breaker as the main circuit terminal. It is a perspective view in a state where it is connected to, that is, the charging part is closed.

Prior to the description of the features of the protective shutter according to each embodiment of the present application, the configuration of the closed switchboard to be mounted will be described. In the closed switchboard 1, as shown in FIG. 2, the board-side housing 8 to which wiring (not shown) is connected to the back side and the board-side housing 8 are approached and pulled out in the horizontal direction (x direction). A circuit breaker chamber is formed in combination with the circuit breaker 9 which is a movable compartment of the above. In this example, for example, it is described as a closed switchboard 1 of a three-phase three-wire system consisting of a U phase, a V phase, and a W phase and an AC 24 kV class. Further, the vertical direction (vertical direction) is the z direction, the pull-out direction of the breaker 9 in the horizontal direction is the x direction, the direction in which the phases are lined up (horizontal direction) is the y direction, and the direction from the front side to the back side is the positive of x. Described as the direction.

A total of 6 main circuits are connected to the board-side housing 8 on the back side, which is not shown, on the upper side and the load side wiring on the lower side. Each of the terminals 3 is arranged on the front side with the connection surface 3fc facing the circuit breaker 9. In the circuit breaker 9, a connection terminal 92 for making an electrical connection with each of the upper and lower main circuit terminals 3 is projected toward the panel side housing 8, and a switch, an arc extinguishing chamber, and the like are housed in each phase. The blocking mechanism units 91a to 91c (collectively, the blocking mechanism units 91) are arranged side by side in the lateral direction (y direction). Further, a wheel or the like for movement (not shown) is provided for the pull-out operation.

The charging part (high voltage part) of the circuit breaker chamber configured in this way is classified into units such as a bus, a connection (cable), and a circuit breaker. For example, a tubular insulation surrounding the side side of the main circuit terminal 3 is provided. Each is partitioned by a partition such as a bushing 2. Then, during operation, the circuit breaker 9 and the panel-side housing 8 cover (close) the charging portion, so that there is no problem. However, when the circuit breaker 9 or the like is pulled out to the test position, or when the circuit breaker 9 or the like is moved to the outside of the panel, the front portion of the main circuit terminal 3 which is the charging unit on the panel side housing 8 side protrudes as it is. Become. Therefore, as described in the background art, a protective shutter 4 that covers the front surface of the main circuit terminal 3 is provided according to the withdrawal of the circuit breaker 9.

As shown in FIG. 3 (FIGS. 3A and 3B), in order to drive the protective shutter 4 with the movement of the circuit breaker 9, the arm 85 having the pin 85p formed on the board-side housing 8 is linked. The shutter drive mechanism is formed by the 86 and the plate 95 formed on the circuit breaker 9 side. In the state where the circuit breaker 9 is pulled out to the test position (FIG. 3A), the protective shutter 4 is arranged at a position where the opening 2a of the insulating bushing 2 is closed and the connection surface 3fc of the main circuit terminal 3 cannot be seen from the outside. That is, even if the circuit breaker 9 is pulled out of the panel-side housing 8 for maintenance or the like, it is configured so that a person cannot come into contact with the main circuit terminal 3 which is a charging unit.

On the other hand, when the circuit breaker 9 is moved to the connection position, the plate 95 arranged on the circuit breaker 9 pushes up the pin 85p of the arm 85 arranged on the board side housing 8, so that the board side housing 8 of the arm 85 is pushed up. The tip portion 85e on the side rises. Since the tip portion 85e of the arm 85 is inserted into the link 86, the protective shutter 4 interlocking with the link 86 moves upward as the tip portion 85e rises, so that the protective shutter is on the side that opens the opening 2a portion. 4 moves. As a result, the connection terminal 92 of the circuit breaker 9 can be moved to the connection position (the position where the connection terminal 92 is connected to the main circuit terminal 3) without contacting the protective shutter 4.

Based on the above-described configuration, the protective shutter 4 according to the first embodiment will be described. As shown in FIGS. 1A and 1B, the protective shutter 4 has an insulating wall portion 42 arranged on the side facing the connecting surface 3fc of the main circuit terminal 3 and a connecting surface to the insulating wall portion 42. It is composed of a metal plate portion 41 arranged with a gap of 4s in a direction away from 3fc. The insulating wall portion 42 is fixed to the metal plate portion 41 by using a fixing bolt 45 and a spacer 46. The spacer 46 serves to provide a gap 4s between the metal plate portion 41 and the insulating wall portion 42.

Here, if a grounding metal is provided as a composite material behind the insulator (corresponding to the insulating wall portion 42), it becomes a back electrode as described in the background technology, so that creeping discharge that discharges through the surface of the insulator occurs. When it occurs, the discharge becomes easy to spread, and the insulation characteristics are lower than those of the insulator alone. On the other hand, by providing the gap 4s using the fixing bolt 45 and the spacer 46 as in the present application, the influence of the electrode behind the insulating wall portion 42 is eliminated, and the effect of barrier insulation can be obtained. Since the barrier insulating effect is impaired in the positional relationship in which the metal plate portion 41 can be seen from the main circuit terminal 3, it is necessary to set the insulating wall portion 42 so that the metal plate portion 41 can be included in the yz plane.

The insulation distance Li varies depending on the rated voltage, and if it is 220 mm in the illustrated 24 kV class, even a metal plate alone functions as a protective shutter. By using the protective shutter 4 using the insulating wall portion 42 as in the present application, the insulating distance Li (distance between the connection surface 3fc and the surface 4fi of the insulating wall portion 42) can be made shorter than 220 mm. .. That is, the closed switchboard 1 is compactly formed by shortening the total protrusion amount (insulation distance Li + shutter thickness t4) with respect to the connection surface 3fc of the protective shutter 4 and reducing the thickness (length in the x direction) of the circuit breaker chamber. It becomes possible to do.

The distance (interval G4) between the insulating wall portion 42 and the metal plate portion 41 for exerting the above-mentioned effect is not particularly limited, and the region where the main circuit terminal 3 is exposed from the opening 2a of the insulating bushing 2 is a gap. It suffices if it is formed so as to cover 4s. However, considering the difference in the linear expansion coefficient between the metal plate portion 41 and the insulating wall portion 42, the dimensional fluctuation due to the temperature change in the installation environment of the closed switchboard 1, or the dimensional error in manufacturing, the interval G4 is 5 mm or more. It is preferable to set to. Of course, there is no restriction on the upper limit, but from the viewpoint of compactification, that is, from the viewpoint of suppressing the total amount of protrusion from the connection surface 3fc as the protective shutter 4, it is preferable to set it to 10 mm or less.

Further, the suitable thickness of the insulating wall portion 42 differs depending on the voltage class and the dielectric breakdown voltage value of the material. However, practically, if it is a plate material made of a material containing an unsaturated polyester resin as a main component, which is called BMC (Bulk Molding Compound) or SMC (Sheet Molding Compound), the insulating property and the mechanical strength From the viewpoint of ensuring the above, 1.6 mm or more is preferable. On the other hand, in order to reduce the weight, particularly to facilitate the shutter operation using the shutter drive mechanism mechanically interlocked with the above-mentioned movement operation, a thickness of 3 mm or less is preferable.

In this example, since the protective shutter 4 that moves linearly is assumed, the shape of the insulating wall portion 42 and the metal plate portion 41 in the xz plane of the portion covering the opening 2a (cross-sectional shape seen from the side surface). Has been described in the flat case, but is not limited to this. For example, it is possible to obtain the same effect even if it is formed in an arc shape or a curved surface shape corresponding to the rotational movement as shown in the patent document.

Embodiment 2.
In the first embodiment, an example in which a protective wall portion is formed of a plate material has been described. In the second embodiment, an example in which the protective wall portion is formed of a flexible sheet material will be described. FIG. 4 is for explaining the configuration of the protective shutter according to the second embodiment and the closed switchboard using the protective shutter, and similarly to FIG. 1 used in the description of the first embodiment, FIG. 4B- FIG. 4A is a cross-sectional view corresponding to line B, in which FIG. 4A is a cross-sectional view showing a state in which the protective shutter covers the main circuit terminal together with the main circuit terminal, and FIG. 4B is an enlarged counterclockwise view of the protective shutter portion in FIG. 4A. It is a cross-sectional view rotated by 90 °. Also in the second embodiment, the same parts as those described in the first embodiment are designated by the same reference numerals, and FIGS. 2 and 3 used in the first embodiment are incorporated.

As shown in FIGS. 4A and 4B, the protective shutter 4 according to the second embodiment forms a gap 4s with the insulating wall portion 42 made of a flexible sheet material, so that the protective shutter 4 is formed on the xz surface. A metal plate portion 41 having a U-shaped (bow-shaped) shape (cross-sectional shape seen from the side surface) is used. At that time, the shape of the metal plate portion 41 was adjusted so that the rising amounts of both wing portions 41w rising from both end portions 41j were made uniform, the main portion 41m was flattened, and the insulating wall portion 42 could be directly fixed by both end portions 41j.

As a result, the flexible sheet material is stretched and fixed from one end to the other end of both end portions 41j to form the insulating wall portion 42, so that the interval G4 can be set without using fixing bolts, spacers, or the like. It can now be easily kept constant in a plane perpendicular to the x direction. Therefore, it has become easier to assemble as compared with the first embodiment using the plate material.

Then, for the insulating wall portion 42, for example, a sheet material having a thickness of 0.188 mm of PET (Polyethylene Terephthalate) was used. Even in this case, the same insulation performance as in the first embodiment is ensured. Moreover, since it is more resistant to mechanical impact than the plate material, the thickness of the insulating wall portion 42 can be reduced, and a light shutter structure can be obtained. By reducing the weight, the load of shutter drive can be further reduced, and the shutter can be driven without using a complicated drive mechanism or power assist.

In addition, since the sheet material has elasticity, it is resistant to damage during assembly or external impact, and its shape can be easily changed. Therefore, it is possible to handle not only the shape of a flat plate but also the shape of bending or denting using a mold. As a result, not only the structure of the metal plate portion 41 can be changed, but also the shape of the insulating wall portion 42 side can be changed to consider the mounting method. The degree has also increased.

Modification example.
In the above example, the metal plate portion 41 is shaped like a bow having a U-shaped cross section, and the metal plate portion 41 is arranged with a gap 4s from the insulating wall portion 42. It is not limited to. For example, conversely, by making the metal plate portion 41 into a flat plate and attaching the insulating wall portion 42 formed by bending the plate material or the sheet material to the metal plate portion 41, a gap 4s is formed between the metal plate portion 41 and the metal plate portion 41. You may try to do it.

It should be noted that although various exemplary embodiments and examples are described in this application, various features, embodiments, and functions are specific embodiments as described in one or more embodiments. It is not limited to the application of the contents disclosed in the form, but can be applied to the embodiment alone or in various combinations. Therefore, innumerable variations not exemplified are envisioned within the scope of the techniques disclosed herein. For example, it includes cases where at least one component is modified, added or omitted, and further, at least one component is extracted and combined with the components disclosed in other embodiments. do.

For example, the three-phase three-wire system is described as a closed switchboard 1 of 24 kV, but the present invention is not limited to this, and different phase wire systems and different voltage classes can be applied. Furthermore, even direct current can be applied. Further, the material of the insulating wall portion 42 is not limited to the described material, and can be appropriately changed in consideration of the dielectric breakdown voltage, weather resistance, and the like. Further, the closed switchboard 1 generally has a structure in which the circuit breaker 9 is pulled out in the horizontal direction, but the structure is not limited to this. For example, it can be applied if the structure is such that the closing of the charging part is released when the connection between the circuit breaker 9 and the main circuit terminal 3 is disconnected (corresponding to the drawer of this example) as needed for inspection, repair, etc. Is.

As described above, according to the protective shutter 4 according to each embodiment, when the circuit breaker 9 in the closed switchboard 1 is pulled out with respect to the panel side housing 8, the main circuit terminal 3 of the panel side housing 8 is used. The protective shutter 4 that covers the main circuit terminal 3 is on the side away from the main circuit terminal 3 with respect to the insulating wall portion 42 facing the main circuit terminal 3 (connection surface 3fc) and the insulating wall portion 42. It is configured to include a metal plate portion 41 arranged with a gap of 4s. As a result, it is possible to surely achieve both shortening of the insulation distance Li and suppression of leakage current, and to form a compact and highly reliable closed switchboard 1.

If the distance G4 in the gap 4s is within the range of 5 mm or more and 10 mm or less, the gap 4s is surely secured and the insulation distance Li is ensured even if there is a dimensional change due to a temperature change without requiring particularly strict dimensional accuracy. Can be surely shortened.

If the gap 4s is configured to cover a region corresponding to the opening 2a of the insulating bushing 2 that partitions the periphery of the main circuit terminal 3, reliable insulation can be achieved.

The metal plate portion 41 has a bow shape in cross section, and if the insulating wall portion 42 is formed of a flexible sheet material stretched from one end to the other end of the bow shape (both ends 41j), a gap 4s is formed. The structure to have can be easily manufactured. In addition, it is lightweight, resistant to mechanical damage, and has increased durability.

Even if the insulating wall portion 42 is provided with a curved portion for forming the gap 4s, a structure having the gap 4s can be easily manufactured.

Further, according to the closed switchboard 1 according to each embodiment, the above-mentioned protective shutter 4 and main circuit terminal 3 are arranged on the front side, and the bus and the load wiring are connected to the main circuit terminal 3 on the back side. The main circuit terminal 3 is covered when the circuit breaker 9 facing the front side of the board-side housing 8 and the board-side housing 8 and configured to be freely retractable, and the circuit breaker 9 are pulled out from the board-side housing 8. Since the shutter drive mechanism (formed by the arm 85 having the pin 85p, the link 86, and the plate 95) for driving the protective shutter 4 at the position is provided, the size is small and the reliability is high.

1: Closed switchboard, 2: Insulated bushing, 3: Main circuit terminal, 4: Protective shutter, 41: Metal plate, 42: Insulated wall, 4s: Gap, 8: Board side housing, 85: Arm (shutter drive) Mechanism), 85p: Pin (shutter drive mechanism), 86: Link (shutter drive mechanism), 9: Circuit breaker, 91: Breaker mechanism, 95: Plate (shutter drive mechanism), 92: Connection terminal, G4: Spacing, Li: Insulation distance, t4: Shutter thickness.

Claims (4)

A protective shutter that covers the main circuit terminals of the board-side housing when the circuit breaker in the closed switchboard is pulled out to the board-side housing.
It is provided with an insulating wall portion facing the main circuit terminal when covering the main circuit terminal, and a metal plate portion arranged with a gap on the side away from the main circuit terminal with respect to the insulating wall portion.
The metal plate has a bow-shaped cross section.
A protective shutter characterized in that the insulating wall portion is formed of a flexible sheet material stretched from one end to the other end of the bow shape . The protective shutter according to claim 1, wherein the gap in the gap is within a range of 5 mm or more and 10 mm or less. The protective shutter according to claim 1 or 2, wherein the gap is formed over a region covering a portion corresponding to an opening of an insulating bushing that partitions the periphery of the main circuit terminal. The protective shutter according to any one of claims 1 to 3 .
The board-side housing in which the main circuit terminal is arranged on the front side and the bus and the load wiring are connected on the back side to the main circuit terminal.
The circuit breaker facing the front side of the board-side housing and configured to be freely retractable, and the protective shutter at a position covering the main circuit terminal when the circuit breaker is pulled out from the board-side housing. Shutter drive mechanism to drive,
A closed switchboard characterized by being equipped with.

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