The present invention relates to a stationary induction electric apparatus such as a transformer or a reactor, and particularly to a stationary induction electric apparatus in which an iron, core is configured using a winding iron core.
Most of stationary induction electric apparatuses such as transformers or reactors have iron cores configured using magnetic material, and a structure called “winding iron core” has been widely used, particularly, for an iron core of a stationary induction electric apparatus with a reIatively-small capacity of a few MVAs or lower to improve workability. The winding iron core is generally configured by circularly bending laminated magnetic metal ribbons cut in a strip shape. In the case of a winding iron core having the simplest structure, the magnetic metal ribbons with the same width are laminated to configure the winding iron core. In this case, the cross-section of the winding iron core that is orthogonal to a closed curve drawing the circle of the iron core is generally formed in a rectangular shape.
The winding of the stationary induction electric apparatus having the iron core is wound around the outer edge of the cross-section of the iron core as close as possible. It is reasonable to maximize the space factor that is a ratio of the area occupied by the cross-section of the iron core to the area occupied by the winding. The dimension of the main body of the stationary induction electric apparatus and the loss can be reduced by maximizing the space factor. Accordingly, a winding is wound in a rectangular shape in many cases in the case of a winding iron core having a rectangular cross-section. Alternatively, a winding is wound in an oval shape or in a racetrack manner in many cases due to workability such as bending of electric wires configuring the winding.
Further, it is required for a winding to withstand electromagnetic force generated when current accidentally flows. In general, when the capacity of the stationary induction electric apparatus is increased, the electromagnetic force becomes large. When the electromagnetic force to withstand becomes large, a circular winding is generally economical to satisfy the electromagnetic force resistance as compared to that formed in a rectangular, oval, or racetrack shape.
Thus, a circular winding is selected for a stationary induction electric apparatus with a relatively-large capacity of a few MVAs or larger, and the space factor is considerably reduced in the case of an iron core having a rectangular cross-section. Accordingly, the cross-section of the iron core is required to be formed nearly in a circular shape, and an iron core with substantially a circular cross-section of a laminated iron core is adopted for a stationary induction electric apparatus with a large capacity. The laminated iron core configures an iron core circle by combining elements obtained in such a manner that magnetic metal ribbons having various shapes are combined and laminated in a circle of a frame shape. The iron core circle is generally in a frame shape, and the widths of the magnetic metal ribbons configured by laminating the iron core circle are changed to realize an iron core with substantially a circular cross-section.
As described in Japanese Unexamined Patent Application Publication No. 2009-296005, there is a well-known method for a winding iron core in which an iron core with substantially a circular cross-section is realized by changing the widths of magnetic metal ribbons while laminating the same as similar to the laminated iron core, and the iron core is wound in a circular shape to configure a winding iron core with substantially a circular cross-section. Further, the iron core is divided into plural sections in the middle of the circle as described in Japanese Unexamined Patent Application Publication No. 2009-296005.
In order to increase the capacity of a stationary induction electric apparatus, it is desirable that a winding is wound in a circular shape to improve the electromagnetic force resistance and the cross-section of an iron core is formed in a circular shape to improve the space factor in accordance with the winding. Further, if the iron core can be realized using a winding iron core, the manufacturing process can be shortened, leading to the improvement of economics.
The technique described in Japanese Unexamined Patent Application Publication No. 2009-296005 is advantageous in that while using a general method of realizing the circular cross-section using the winding iron core, the lengths of the magnetic metal ribbons handled at a time are prevented from being increased by dividing the winding iron core into plural sections in the middle of the circle, and the improvement of workability and the expansion of producible capacity in facilities can be realized. On the other hand, unlike a laminated iron core with a circular cross-section that is common in a large-capacity apparatus, it is necessary to provide a support structure in a window to support the iron core because wider faces of the magnetic metal ribbons are located inside the window of the iron core, and further the support member is complicated due to the circular cross-section. Thus, the size of the window is increased, and the amount of use of iron core material is disadvantageously increased.
An object of the present invention is to provide a stationary induction electric apparatus having a simple iron core support structure and having a winding iron core with a circular cross-section in which plural winding iron cores with rectangular cross-sections of the stationary induction electric apparatus are arranged in the width direction of magnetic metal ribbons configuring the winding iron core to form one winding iron core, the laminated thickness of each winding iron core with a rectangular cross-section is changed, the respective rectangular cross-sections are centered in the laminated direction to be formed in a circular shape in a space inside the winding, and faces of yokes of the iron core inside a window of the winding iron core with a rectangular cross-section are aligned on the same plane.
In order to address the above-described problem, the present invention provides a stationary induction electric apparatus the main body of which is configured by including an iron core having, at least, two iron core legs and a winding wound around each iron core leg. The iron core is a winding iron core obtained by bending laminated magnetic metal ribbons in a circular shape, and the winding iron core is configured using a winding iron core block group in which plural winding iron core blacks each of which has a rectangular cross-section and which have different laminated thicknesses are arranged in the width direction of the magnetic metal ribbons. The cross-section of the iron core in the width direction and the laminated direction of the magnetic metal ribbons becomes a stepped circular cross-section in the case of an iron core leg, and straight sides are located in a window in the case of a yoke. Accordingly, the yoke in the window can be supported on a plane, and a support structure for the iron core can be simplified.
According to the present invention, in the case where a winding iron core with a circular cross-section is applied to a stationary induction electric apparatus, support structures of yokes can be simplified, the size of a window of the iron core can be minimized, and the dimension of the iron core can be reduced.
In the present invention, an iron core of a stationary induction electric apparatus is configured using a winding iron core block group in such a manner that plural winding iron core blocks having different laminated thicknesses and rectangular cross-sections each of which is obtained by bending laminated magnetic metal ribbons in a circular shape are arranged and combined in the width direction of the magnetic metal ribbons. The cross-section of the iron core in the width direction and the laminated direction of the magnetic metal ribbons becomes a stepped circular cross-section in the case of an iron core leg, and straight sides are located in a window in the case of a yoke.
Accordingly, the yoke in the window can be supported on a plane, and a support structure for the iron core can be simplified.
Embodiments of the present invention will be described using
The present invention is particularly applied to means allowing the iron core leg 1A of the winding iron core shown in
In the embodiment, an example of a configuration using five winding iron core blocks is shown. However, the similar configuration can be realized using three or more winding iron core blocks.
In the embodiment, an example of a configuration using five winding iron core blocks is shown. However, the similar configuration can be realized using three or more winding iron core blocks.
It should be noted that the present invention is not limited to the single-phase two-leg structure of
Number | Date | Country | Kind |
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2014-162020 | Aug 2014 | JP | national |