JPH0646611B2 - Transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a transformer with a small current and a high voltage, such as a gas-insulated test transformer, and is particularly caused by a flashover on the load side. The present invention relates to a transformer provided with means for preventing generation of corona due to dielectric voltage of the high-voltage side wheel such as protection from surge voltage.

<Prior Art> Conventionally, as a high-voltage transformer of this type, for example, as shown in FIGS. 5 and 6, for improving the winding workability of the high-voltage side wire wheel 6 wound in multiple layers, etc. For this reason, the high-voltage side wire wheel 6 is divided into a pair of wire wheel blocks 7 and 8, and the wire wheel blocks 7 and 8 are wound so as to be symmetrical to each other, and both wire wheel blocks 7 and 8 are rotated. It is composed by arranging on the left and right of the direction,
A so-called side-by-side winding structure may be used.

In the high-voltage coil 6 having such a structure, the winding start end of the coil is connected to the center a of the potential fixing plate 5 wound around the winding form 4 in the axial direction, and the coil is connected to the winding form 4 with the coil. It is formed by alternately winding an interlayer insulating sheet, and connects the winding end ends of the coil blocks 7 and 8 to a high-voltage shield 9 and a high-voltage terminal 10 arranged on the outermost periphery of the coil 6, respectively. In FIG. 6, reference numeral 1 is an iron core, and 3 is a low-pressure side wheel.

By the way, in the high-voltage side wire wheel 6 wound in multiple layers as described above, in order to efficiently radiate the Joule heat generated inside the wire wheel 6 at the time of inducing a high voltage, each wire wheel block 7, 8 is
A plurality of spacer members 16 (not shown) are provided at predetermined intervals in the middle portion (center portion in the drawing) of the winding layer to form an annular cooling duct 14 penetrating in the axial direction of the coil. Insulating gas is also circulated inside the coil. Then, in this cooling duct 14 part, both the wire wheel blocks 7 and 8 are separated into respective block parts 7a, 7b, 8a and 8b, and a potential fixing plate 15 for preventing dielectric breakdown due to surge voltage in this part. Is provided.

The potential fixing plate 15 is formed by winding a conductive foil on a sheet from the inner peripheral surface to the outer peripheral surface of the duct 14 when the cooling duct 14 is formed. The winding end and winding start end of each of the side-by-side winding wheel blocks 7 and 8 in the winding layer middle portion facing the duct 14 are connected.

<Problems to be Solved by the Invention> However, in such a wire ring structure, the coils of the wire ring blocks 7 and 8 that are adjacent to the both ends of the potential fixing plate 15 inside and outside the potential fixing plate 15 are provided. On the other hand, a potential difference of approximately one layer is applied, and since the potential fixing plate 15 is formed of an extremely thin conductive foil as described above, the both ends are formed in an acute angle shape. There is a problem in that the electric field is concentrated and corona discharge occurs.

As a means for solving such a problem, for example, a so-called round edge in which both end portions of the potential fixing plate 15 are formed in a circular shape can be considered. In this case, at least both end portions of the potential fixing plate 15 are formed. Since the thickness is increased, the diameter of the high pressure side wire ring 6 is correspondingly increased, and there is another problem that the working operation is considerably complicated.

In view of such conventional problems, the present invention has a cooling duct formed in the middle portion of the winding layers of the side-by-side winding high-voltage side coils, in which the corona discharge in the edge portion of the potential fixing plate wound around this cooling duct portion The purpose is to prevent the occurrence.

<Means for Solving the Problems> In order to achieve such an object, in the present invention, each winding end and winding start in the winding layer intermediate portion facing the cooling duct of each coil block of the side-by-side high voltage side coil are wound. The end is connected to the axial outer end portion of the potential fixing plate, respectively.

<Examples> Hereinafter, the present invention will be described in detail based on Examples shown in the drawings. In this embodiment, the present invention is applied to a transformer for gas insulation test.

FIG. 1 is an equivalent circuit diagram schematically showing a high-voltage side wheel, which is a component of the present invention, FIG. 2 is a partially cutaway front view of a transformer of this embodiment, and FIG. FIG. 4 is an enlarged cross-sectional view showing a part taken out, and FIG. 4 is a perspective view showing a state where the high-pressure side wheel is being formed. In these figures, reference numeral 1 is an iron core made of a silicon steel plate or the like. A winding form 2 is attached to a part of the iron core 1, and a coil (not shown) made of, for example, a synthetic resin-coated copper wire and an interlayer insulating sheet (not shown) made of a plastic film sheet are provided on the winding form 2. The low-pressure side wheel 3 is formed by alternately winding. The winding start end and the winding end end of the low-voltage side wire wheel 3 are connected to low-voltage terminals (not shown).

A winding form 4 is mounted on the low-voltage side wire wheel 3 so that the first potential fixing plate 5 made of a conductive thin plate such as copper or aluminum does not form one turn on the winding form 4. Wrapped around. On the first potential fixing plate 5, there is formed a multi-layered side-by-side high voltage side coil 6 which is formed by alternately winding the same coil as the low voltage side coil 3 and an interlayer insulating sheet.

The high-pressure side wire wheel 6 is composed of a pair of wire wheel blocks 7 and 8 which are divided into two parts so as to be symmetrical to each other. Each wheel block 7,8
Has its winding start end connected to the axial center a of the first potential fixing plate 5, and then winds in the opposite directions while winding in opposite directions, and after winding the first layer symmetrically, The interlayer insulating sheet is wound several times to rewound to form the second layer.
By winding a predetermined number of layers in this manner, the side-by-side winding high-voltage side coil 6 is formed.

A high-voltage shield 99 and a high-voltage terminal 10 are provided on the outermost periphery of the high-voltage side wire wheel 6, and the high-voltage shield 9 is connected to the winding end ends of the two wire wheel blocks 7 and 8, respectively.
Further, the first potential fixing plate 5 is connected to the ground side terminal 12 via the lead wire 11. The transformer contents having such a structure are housed in an iron pressure vessel 13 in which a non-combustible insulating gas such as sulfur hexafluoride (SF ₆ ) is enclosed.

In the transformer having such a basic structure, the high-voltage side wheel 6 has an annular cooling duct 14 penetrating in the axial direction of the winding layer in the central portion of the winding layer, and an inner peripheral surface to an outer peripheral surface of the cooling duct 14. It has a potential fixing plate 15 wound so that one turn is not formed over the entire length.

The cooling duct 14 is formed by interposing a plurality of pin-shaped spacer members 16 ... On the other hand, the second potential fixing plate 15 is made of, for example, a conductive metal foil sheet of copper, aluminum or the like, and its width dimension is set smaller than the axial width dimension of the high voltage side wire ring 6.

Further, in the respective wire ring block portions 7a, 7b, 8a, 8b divided into the inside and the outside by the cooling duct 14, the winding end and the winding start end facing the cooling duct 14 are the shafts of the respective wire block 7, 8. It is wound so as to be located at the outer end in the direction, of which the winding end ends of the inner wire ring block portions 7a, 8a are respectively the outer end portions c, c of one of the second potential fixing plates 15. Each outer wheel block part 7 connected to c and outside
The winding start ends of b and 8b are the other outer end portions d and d of the potential fixing plate 15.
, So that the winding end ends of the inner line wheel block portions 7a, 8a and the winding start ends of the outer line wheel block portions 7b, 8b are maintained at substantially the same potential.

In the above structure, as shown in FIG. 1, the second potential fixing plate 15 has the same potential as the winding end end and winding start end of each of the inner and outer coil block portions 7a, 7b, 8a, 8b. Therefore,
The electric field at the edge portions e at both ends of the potential fixing plate 15 is extremely small in combination with the fact that the potential fixing plate 15 has a width smaller than that of the high voltage side wire ring 6 and enters the wire ring 6. . Therefore, even if the second potential fixing plate 15 is made of an extremely thin conductive foil and both edge portions thereof are sharp, generation of corona discharge is suppressed.

The cooling duct 14 and the second potential fixing plate 15 are formed at the same time when the high voltage side coil 6 is wound. That is, as shown in FIG. 4, the coils and the insulating sheets that form the coil blocks 7 and 8 are wound alternately until the winding end diameter of the high voltage side coil 6 becomes approximately half. Next, the coil is cut off at one end and the inner wheel block portions 7a, 8a are cut.
And the winding end of this coil is connected to one end of the second electric potential fixing plate 15, and then the electric potential fixing plate 15 is wound by one turn of the inner ring block portions 7a, 8a. . At that time, as shown in FIG. 5, the plurality of spacer members 16 are attached to the outer surface of the winding portion of the potential fixing plate 15 at predetermined pitches via a separately prepared double-sided adhesive tape. Further, the second potential fixing plate 15 is superposed on each spacer member 16 and wound about one turn, and the winding start end of the coil is connected to the other end side of the potential fixing plate 15 and the coil is The outer winding block portions 7b and 8b are alternately wound with the insulating sheet. The radial dimension of the cooling duct 14 thus formed is set to, for example, about 20 to 30 times the interlayer dimension.

The second potential fixing plate 15 can be modified in various ways, such as by connecting a plurality of rectangular plate-shaped foil pieces with conductive wires.

Further, in the above-mentioned embodiment, the cooling duct 14 is provided at one location in the center of the high-voltage side wire wheel 6, but the high-pressure side wire wheel 6 is divided into multiple stages as required, and each step is similar to the above. It is also possible to form the cooling duct 14 with a configuration.

Further, it goes without saying that the present invention can be applied to a case where the high-voltage side wire wheel 6 is divided into a plurality of three or more wire wheel blocks 7 and 8.

<Effects of the Invention> As described above, according to the present invention, in the coil having the cooling duct formed in the middle portion of the winding layers of the side-by-side winding high-voltage side coils, each of the winding layer intermediate portions facing the cooling duct of each coil block is provided. The winding end end and the winding start end of each coil block are located at the axial outer end portion of each coil block, and these winding end end and winding start end are respectively connected to the axial outer end portion of the potential fixing plate. Therefore, the electric field at the edge portions of both ends of the potential fixing plate can be made extremely small. Therefore, it is possible to suppress the occurrence of corona discharge at the edge portions of both ends of the potential fixing plate, and it is possible to prevent a burnout accident of the insulating sheet or the coil adjacent to the potential fixing plate.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention, FIG. 1 is an equivalent circuit diagram schematically showing a high-voltage side coil which is a constituent member of the present invention, and FIG. 2 is a transformer of this embodiment. Partially broken front view, FIG. 3 is an enlarged cross-sectional view showing the main part of the same, FIG. 4 is a perspective view showing the formation of the high-pressure side wheel, and FIG. 5 is a main-part cross-sectional view showing a conventional example. FIG. 6 is an equivalent circuit diagram schematically showing the high-voltage side line wheel of the conventional example shown in FIG. 6 ... High-voltage side wire wheel, 7, 8 ... Wire wheel block, 14 ... Cooling duct, 15 ... Potential fixing plate, c, d ... Axial outer end of the potential fixing plate.

Claims (1)

[Claims] 1. A transformer in which a cooling duct is formed in an intermediate portion of a winding layer of a high-voltage side coil, and a potential fixing plate is wound from an inner peripheral surface of the cooling duct to an outer peripheral surface thereof. At least one side-by-side winding in this axial direction
It is configured by a pair of wire wheel blocks, and each winding end and winding start in the winding layer middle portion facing the cooling duct of each wire block is connected to the axial outer end of the potential fixing plate. Characteristic transformer.