JP2021083175A - Bus arrangement structure and enclosed switchboard - Google Patents

Abstract

To provide a bus arrangement structure in which a temperature increase due to heat generation in a bus can be suppressed, and an enclosed switchboard provided with the bus arranged so as to achieve the suppression.SOLUTION: In a bus arrangement structure according to an embodiment, a plurality of horizontal buses 5 are arranged in an arrangement permitted region the upper end and the lower end of which are restricted by other members on an enclosed switchboard 1, and each of the horizontal buses 5 are arranged at equal interval in the vertical direction between a top plate 2c which is a member at the upper end of the arrangement permitted region and a bottom plate 2d which is a member at the lower end. The member at the upper end and/or the member at the lower end is formed from a conductor.SELECTED DRAWING: Figure 1

Description

An embodiment of the present invention relates to a bus arrangement structure in which a bus is arranged in a switchboard, and a closed switchboard including a bus arranged in the arrangement structure.

Conventionally, for example, a closed switchboard that accommodates a horizontal bus connected to a three-phase AC power supply and a vertical bus connected to the horizontal bus is known. Since the bus of such a closed switchboard generates heat when power is supplied, for example, Patent Document 1 proposes to suppress heat generation by providing a plurality of sets of vertical bus.

Japanese Patent No. 6173579

By the way, in recent years, it has been required to raise the rating of the supplied electric power with the high integration of closed switchboards.

However, it turns out that raising the rating creates new problems. Specifically, since a larger current flows through the bus due to the increased rating, in addition to the heat generated by the bus itself, nearby conductors are induced to generate heat, and the temperature inside the closed switchboard meets the required specifications. It turned out that there is a risk of rising beyond that.

Therefore, a closed switchboard having a bus arrangement structure capable of suppressing a temperature rise due to heat generation of the generatrix and a bus having such an arrangement is provided.

The busbar arrangement structure of the embodiment is a structure for arranging a plurality of horizontal busbars on the switchboard, and the plurality of horizontal busbars can be arranged in the switchboard in which the upper end and the lower end are restricted by other members. In addition to being arranged in the area, the horizontal busbars are arranged vertically at equal intervals between the upper end member and the lower end member of the displaceable area, and the upper end member and the lower end member are arranged. At least one of them is made of a conductor.

Further, the closed switchboard of the embodiment is provided at least one of the upper end and the lower end of the arrangeable region formed of a conductor and arranged with the horizontal bus arranged in the above-mentioned bus arrangement structure and where the horizontal bus can be arranged. It is provided with a member and a member.

The figure which shows typically the arrangement structure of the bus of the embodiment and a closed switchboard in a side view. The figure which shows the arrangement structure of the bus and the state which the closed switchboard is seen from the back side schematically. The figure which shows the arrangement structure of the generatrix and the closed switchboard schematically in a plan view. The figure which shows typically the arrangement structure of other generatrix The figure which shows typically the allowable range at the time of installation of a horizontal bus

Hereinafter, embodiments will be described with reference to the drawings.

The closed switchboard 1 according to the present embodiment is a rectangular parallelepiped housing 2 formed so as to be long in the vertical direction as shown in FIG. 1 and substantially the same length in the front-rear direction and the left-right direction as shown in FIGS. 2 and 3. I have. Hereinafter, as shown in FIGS. 1 to 3, the vertical direction of the closed switchboard 1 is also referred to as a vertical direction, and the front-rear direction is also referred to as a depth direction.

As shown in FIG. 1, the closed switchboard 1 is provided with an equipment accommodating chamber 3 on the front plate 2a side, and can accommodate a plurality of equipment such as a motor control device in the vertical direction. Further, the closed switchboard 1 is provided with a bus accommodation chamber 4 on the rear plate 2b side. The horizontal bus 5 and the vertical bus 6, which are conductors for supplying electric power to each device, are housed inside the bus accommodation chamber 4. At this time, each horizontal bus 5 is arranged so as to be within a predetermined disposable area (H) and to have a predetermined bus structure, although details will be described later.

The rear plate 2b of the closed switchboard 1, that is, the outer panel on the side of the closed switchboard 1 facing the horizontal bus 5, has an intake port 7 located on the lower end side and communicating with the outside, and an intake port 7 located on the upper side and communicating with the outside. An exhaust port 8 is provided. The intake port 7 and the exhaust port 8 are formed, for example, by forming a slit in the rear plate 2b, forming an opening in the rear plate 2b so that the rear plate 2b can be covered with a net member, a filter member, or the like.

At this time, although the exhaust port 8 depends on the number of horizontal bus 5 to be arranged, for example, when four horizontal bus 5 are arranged as shown in FIG. 1, the exhaust port 8 is more than the horizontal bus 5 arranged at the uppermost stage. It can be provided so as to be located above. Further, the intake port 7 can be provided so as to be located below the horizontal bus 5 arranged at the bottom, although it depends on the number of the horizontal bus 5 to be arranged. As a result, each horizontal bus 5 can be cooled by the introduced air, and the air that has cooled each horizontal bus 5 is discharged, so that the cooling efficiency can be improved.

These horizontal buses 5 are made of a copper material and are connected to a single system power supply (not shown) by a three-phase four-wire system wiring. Further, in the present embodiment, the horizontal bus 5 is provided with a total of four horizontal bus lines, three of which are so-called R-phase, S-phase, and T-phase, and one of N-phase corresponding to the midpoint. .. In FIG. 1, the horizontal bus 5 of the R phase is shown as 5 (R), the horizontal bus 5 of the S phase is shown as 5 (S), the horizontal bus 5 of the T phase is shown as 5 (T), and the horizontal bus of the N phase is shown as 5 (T). The bus 5 is shown as 5 (N). As shown in FIG. 2, these horizontal buses 5 extend in the left-right direction of the closed switchboard 1 and are electrically connected to the corresponding vertical buses 6 by connecting conductors 9. In FIG. 2, the vertical bus 6 is not shown.

Then, in the case of the present embodiment, the horizontal bus 5 is physically formed between the top plate 2c and the bottom plate 2d of the closed switchboard 1, that is, the top plate 2c and the bottom plate 2d whose upper and lower ends are other members. In other words, it is arranged within the physically defined displaceable area (H). At this time, at least one of the top plate 2c and the bottom plate 2d is formed of a conductor. In the case of this embodiment, both the top plate 2c and the bottom plate 2d are formed of conductors, and a washed steel plate is used as the conductors. This washed steel sheet is an iron alloy having a carbon content of about 0.1%. However, the structure of the conductor is an example, and iron alloys having different carbon contents can be adopted as long as they have electrically equivalent characteristics.

The horizontal bus 5s are arranged at equal intervals with each other separated by a first distance (X), and the uppermost horizontal bus 5 is separated from the top plate 2c by a second distance (Y). The lowermost horizontal bus 5 is arranged so as to be separated from the bottom plate 2d by a second distance (Y). However, the second distance (Y) is set to a value or more that can secure an insulation distance predetermined by a safety standard or the like.

Further, each vertical bus 6 is formed in an L shape in a cross-sectional view as shown in FIG. 3, and is arranged in individual ducts 10 arranged in the vertical direction. The duct 10 is formed in a substantially elongated square cylinder shape extending in the vertical direction in the closed switchboard 1. That is, the duct 10 has a structure in which warmed air easily moves upward due to convection. Further, the duct 10 is formed with an opening at a position corresponding to the connection terminal of the device. As a result, by inserting the equipment accommodated in the equipment accommodating chamber 3 from the front and pushing it backward, the terminal portion meshes with the L-shaped short side of the vertical bus 6 to supply power.

Next, the operation of the above configuration will be described.
As described above, when the rating of the closed switchboard 1 is raised, a larger current flows through the bus, so in addition to the heat generated by the bus itself, the nearby conductors are induced to heat and generate heat, and the inside of the closed switchboard 1 is heated. There is a problem that the temperature may rise beyond the required specifications. Therefore, in order to suppress the influence of the induction heating, that is, the heat generation, the arrangement should be such that the influence of one horizontal bus 5 on the other horizontal bus 5 is small.

Now, when another conductor exists in the vicinity of one conductor, it is known that the energy that affects the other conductor due to the change in magnetic flux when a current flows is inversely proportional to the distance between the conductors. .. Therefore, in order to reduce the energy affecting other conductors, it can be seen that the distance between the horizontal bus 5s should be as wide as possible. Then, in the case of arranging the upper end and the lower end in the distributable area (H) restricted by other members, in order to arrange the horizontal bus 5 in the state of being separated as much as possible, the horizontal bus 5 is arranged. It can be seen that the first distance (X), which is the distance between them, should be made equal.

Therefore, in the present embodiment, the first distance (X) between the horizontal bus 5s is made uniform, and the horizontal bus 5s are arranged at equal intervals in the vertical direction within the distributable area (H). As a result, the energy due to the influence of the horizontal bus 5s can be minimized, and the heat generated by the induction heating can be suppressed.

By the way, since the housing 2 of the closed switchboard 1 is generally made of a steel plate or the like, a conductor other than the other horizontal bus 5 exists in the vicinity of the horizontal bus 5. Then, even when the housing 2 is induced to be heated, the temperature inside the closed switchboard 1 will rise. Therefore, considering the influence on other conductors arranged so as to be adjacent to the horizontal bus 5, here, the top plate 2c and the bottom plate 2d that limit the upper end and the lower end of the distributable region (H), It is considered that the effect of further reducing heat generation can be expected.

Therefore, in the present embodiment, in order to suppress the influence on each of the other horizontal bus 5, each horizontal bus 5 is arranged at equal intervals at the first distance (X), and the uppermost horizontal bus 5 (R) and the sky are arranged. The second distance (Y), which is the distance between the plate 2c and the lowermost horizontal bus 5 (N) and the top plate 2c, is set as follows.

Focusing on the horizontal bus 5 (R) arranged at the top, the energy (P1) that affects the adjacent horizontal bus 5 (S) is P1 = α × (1 / X) ^ 2. The energy (P2) that affects the top plate 2c is P2 = β × (1 / Y) ^ 2. Therefore, for the horizontal bus 5 (R), the energy (Pr) that affects the external conductor is Pr = α × (1 / X) ^ 2 + β × (1 / Y) ^ 2. Note that α and β are coefficients depending on the shape and properties of the conductor, and “^” indicates the square.

Further, the horizontal bus 5 (S) sandwiched between the other horizontal bus 5 (R, T) on both sides affects the energy (Ps) on the two adjacent horizontal bus 5, and the horizontal bus 5 (S) on both sides is the other horizontal. The energy (Pt) that the horizontal bus 5 (T) sandwiched between the bus 5 (S, N) affects the two adjacent horizontal bus 5 is Ps = Pt = 2 × α × (1 / X), respectively. ) ^ 2. Focusing on the horizontal bus 5 (N) arranged at the bottom, the energy (Pn) is Pn = α × (1 / X), as in the horizontal bus 5 (R) at the top. It becomes ^ 2 + β × (1 / Y) ^ 2.

Since the total energy (P) when affecting other conductors in the above bus structure can be obtained as the total of each energy, α is calculated based on the electrical characteristics of the horizontal bus 5 formed of the copper material. The total energy (P) can be obtained as a function of X and Y by setting and setting β based on the electrical characteristics of the top plate 2c and the bottom plate 2d formed of the washed steel plate.

At this time, when the number of horizontal bus 5 is n, the relationship of H = (n-1) × X + 2 × Y is established. Then, since the distributable region (H) can be regarded as substantially the height of the closed switchboard 1, the relationship between X and Y can be obtained. In other words, Y can be expressed as Y = (H− (n-1) × X) / 2 as a function of X. Although X can be expressed as a function of Y, the final arrangement is the same.

Then, X that minimizes the total energy (P) can be obtained, for example, by calculation, or by setting a calculation formula for the total energy (P) in spreadsheet software and changing X in units of several mm or several cm, for example. You can ask. Further, if X is obtained, Y can be specified from the above relationship. Thereby, the values of X and Y that can minimize the calorific value, that is, the arrangement of the horizontal bus 5 that can minimize the calorific value can be specified.

By the way, when X and Y that minimize the total energy (P) described above are obtained, it is found that the ratio (X / Y) obtained by dividing X by Y is approximately 2.64. In other words, if the horizontal bus 5 is arranged so that the ratio (X / Y) of the first distance (X) and the second distance (Y) is approximately 2.64, the calorific value can be minimized. found.

By the way, as shown in FIG. 4, for example, eight horizontal buses 5 may be arranged on the closed switchboard 1. At this time, the first distance (X) when the eight horizontal bus 5s are arranged is shorter than the first distance (X) in FIG. 2 where the four horizontal bus 5s are arranged. In the case of FIG. 4, in the present embodiment, it is assumed that power is supplied to the two horizontal bus 5 for each phase from the power supply of one system, but the horizontal bus 5 of each phase is supplied from the power supplies of two different systems. Each can be configured to supply power.

Even with such a configuration, when the total energy was calculated in consideration of the influence on other conductors and the first distance (X) and the second distance (Y) were obtained, their ratio (X / Y) was obtained. ) Was obtained as a result that X / Y = 2.64. From this result, the ratio (X / Y) of the first distance (X) to the second distance (Y) is in the range centered on about 2.64 regardless of the number (n) of the horizontal bus 5 to be arranged. It was found that the amount of heat generated can be minimized by arranging each horizontal bus 5 so as to be.

In this way, when the upper end and the lower end of the distributable region (H) are defined by the conductor, the first distance (X) is the second distance (Y) regardless of the number of the plurality of horizontal bus 5s. If the ratio (X / Y) divided by) is arranged so as to be within a predetermined range based on about 2.64, the calorific value can be substantially minimized.

However, due to physical restrictions, it is assumed that each horizontal bus 5 cannot be arranged at a position where X / Y = 2.64 exactly. In that case, as shown in FIG. 5 as the allowable target arrangement, the target is the 2.6 position where X / Y = about 2.64, while the total energy is within the allowable range as the specifications of the closed switchboard 1. By setting the deviation as the allowable upper limit and the allowable lower limit and arranging the horizontal bus 5 within the allowable range, the amount of heat generated can be reduced without requiring excessive accuracy in the installation position of the horizontal bus 5.

In this case, as shown as an allowable arrangement in FIG. 5, the upper end or the lower end of the horizontal bus 5 hangs at the 2.6 position, that is, within the range of the vertical width (W) of the horizontal bus 5. By arranging the 6 positions so as to come, it is possible to reduce the amount of heat generated without requiring excessive accuracy in the installation position of the horizontal bus 5.

According to the embodiment described above, the following effects can be obtained.
The plurality of horizontal busbars 5 installed on the closed switchboard 1 are arranged in the disposable area (H) in which the upper end and the lower end are restricted by other members in the closed switchboard 1, and the upper end member. The horizontal busbars 5 are arranged at equal intervals in the vertical direction between the and the lower end member. At this time, at least one of the upper end member and the lower end member is formed of a conductor.

By adopting such a bus arrangement structure, it is possible to suppress a temperature rise due to heat generation of the bus. Further, the horizontal bus 5 arranged in such a bus arrangement structure and the top plate 2c formed of a conductor and provided at at least one of the upper end and the lower end of the distributable area where the horizontal bus 5 can be arranged. The closed switchboard 1 including the member such as the bottom plate 2d and the bottom plate 2d can also suppress the temperature rise due to the heat generation of the bus.

Of the plurality of horizontal bus 5, between the horizontal bus 5 arranged at the uppermost stage and the upper end member such as the top plate 2c, and between the horizontal bus 5 arranged at the lowermost stage and the lower end member such as the bottom plate 2d. Are separated by a predetermined insulation distance. As a result, safety can be ensured.

The members arranged at the upper end and the lower end of the distributable region (H) are conductors such as the top plate 2c and the bottom plate 2d, and the horizontal bus 5s are equidistant from each other with a first distance (X). The horizontal bus 5 arranged at the uppermost stage is arranged with a second distance (Y) from the top plate 2c which is the upper end member.

The horizontal bus 5 arranged at the bottom is arranged so as to have the second distance (Y) between the horizontal bus 5 and the bottom plate 2d, which is a member at the lower end, and is arranged at the first distance (X) and the second distance. (Y) is a value that is inversely proportional to the square of the distance, and the energy that affects the adjacent horizontal bus 5 and other members due to the change in the magnetic field when a current is passed through each horizontal bus 5 is the smallest. It is set to the distance. As a result, the temperature rise due to heat generation of the bus can be suppressed by the physical arrangement of the horizontal bus 5.

In this case, it is assumed that the members arranged at the upper end and the lower end of the distributable region (H) are conductors having the same magnetic characteristics as the horizontal bus 5, and a plurality of horizontal bus 5 are provided by the number (n). Regardless of this, by arranging so that the ratio of the first distance (X) divided by the second distance (Y) is within a predetermined range based on 2.64, the temperature rise due to heat generation of the bus is suppressed. It can be an arrangement structure that can be used. In this case, the target position for placement is, for example, within a range of 10% based on the amount of energy when the ratio is about 2.64, or the horizontal bus 5 is placed in a state where a part of the horizontal bus 5 hangs on the target position. As a result, it is possible to suppress the need for excessive position accuracy, and it is possible to reduce the risk of impairing productivity and workability.

By providing the connecting conductor 9 that connects the horizontal bus 5 and the vertical bus 6 that is arranged orthogonally to the horizontal bus 5, the heat generated by the horizontal bus 5 can be dissipated by the vertical bus 6 and the heat is generated. Can be suppressed. At this time, by arranging the vertical bus 6 in the duct 10 extending upward as in the embodiment, cooling by natural convection can be promoted, and the temperature rise in the closed switchboard 1 can be further reduced.

Further, in the embodiment, the arrangement is made in consideration of the influence on the adjacent conductors. For example, in FIG. 2, the influence from the horizontal bus 5 (R) is determined by the horizontal bus 5 (T), the horizontal bus 5 (N), or the bottom plate. The arrangement structure of each horizontal bus 5 can also be determined in consideration of 2d. Even in that case, by arranging the ratio obtained by dividing the first distance (X) by the second distance (Y) so as to be within a predetermined range based on 2.64, the temperature due to heat generation of the bus is generated. The arrangement structure can suppress the rise, and the temperature rise in the closed switchboard 1 can be reduced. Further, the above-mentioned bus arrangement structure can be applied to a switchboard other than the closed switchboard 1.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

In the drawing, 1 is a closed switchboard (switchboard), 2c is a top plate (other members), 2d is a bottom plate (other members), 5 is a horizontal bus, 6 is a vertical bus, and 10 is a duct.

Claims (6)

It is a bus arrangement structure for arranging multiple horizontal bus lines on the switchboard.
The plurality of horizontal busbars are arranged in the disposable area in which the upper end and the lower end are restricted by other members in the switchboard, and the upper end member and the lower end member of the disposable area are arranged. The horizontal busbars are arranged in the vertical direction at equal intervals from each other.
At least one of the upper end member and the lower end member is a generatrix arrangement structure formed of a conductor. Of the plurality of horizontal bus lines, the space between the horizontal bus line arranged at the uppermost stage and the upper end member, and the space between the horizontal bus line arranged at the lowermost stage and the lower end member are predetermined. The bus arrangement structure according to claim 1, wherein the busbars are separated by an insulating distance. The horizontal bus lines are arranged at equal intervals with a first distance (X) from each other, and the horizontal bus lines arranged at the uppermost stage have a second distance from the upper end member. The horizontal bus, which is arranged so as to have (Y) and is arranged at the bottom, is arranged so as to have the second distance (Y) between the horizontal bus and the member at the lower end.
The first distance (X) and the second distance (Y) are values that are inversely proportional to the square of the distance, and are adjacent horizontal bus lines and others due to changes in the magnetic field when a current is passed through the horizontal bus lines. The bus arrangement structure according to claim 1 or 2, wherein the energy affecting the members of the above is set to the minimum distance. At least one of the upper end member and the lower end member is made of a steel plate.
The plurality of horizontal buses are made of copper material, and regardless of the number of the horizontal bus, the ratio of the first distance (X) divided by the second distance (Y) is a predetermined ratio based on 2.6. The arrangement structure of the bus according to claim 3, which is arranged within the range. The bus arrangement structure according to any one of claims 1 to 4, wherein the vertical bus lines arranged orthogonally to the above are arranged in a duct extending in the vertical direction in the switchboard. A horizontal bus arranged in the arrangement structure of the bus according to any one of claims 1 to 5.
A member formed of a conductor and provided at at least one of the upper end and the lower end of the distributable region where the horizontal generatrix can be arranged.
Closed switchboard with.

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