JP3444567B2 - Gas insulation induction equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-insulated induction device, and more particularly to a gas-insulated induction device using a transition cable as a winding.

[0002]

2. Description of the Related Art In recent years, a gas-insulated transformer using an incombustible insulating gas as an insulating medium has been attracting attention as a transformer replacing an oil-insulated transformer for disaster prevention reasons. There are various configurations for the windings of a gas-insulated transformer, and one of them is the dry type that performs both cooling and insulation with insulating gas. This dry type gas-insulated transformer uses a more expensive liquid cooling medium than the semi-pool type or spray type that is combined with a liquid cooling medium and the separate type gas-insulated transformer that performs cooling and insulation separately. Since it is not used, the structure is simple, an inexpensive and highly reliable transformer can be manufactured, and it can be applied to a high-voltage and large-capacity transformer.

This dry-type gas-cooled gas-insulated transformer has almost the same structure as a conventional oil-insulated transformer, and uses a wire made of a metal wire and a polymer film stacked as a winding wire. The cooling and insulation are changed from insulating oil to insulating gas.

[0004] In the winding using a wire in which a polymer film is laminated on this wire, the series capacitance of the transformer winding is increased in the same manner as in the case of oil insulation, so that when a lightning impulse voltage is applied. It is well known that the electric potential distribution of is improved and the dielectric strength is improved. Therefore, various winding methods for increasing the series capacitance of the winding have been conventionally developed.

As one of the methods, there is a method of winding a thin shield conductor between the conductors of the winding. By this method, as shown in FIG. 6, when the appropriate windings 13 are electrostatically coupled by the flat conductor 5 serving as a shield conductor, the shield conductor 5 and the winding conductor 13 are closely adhered to each other. The capacitance between the winding conductor 13 and the winding conductor 13 couples between the winding layers, the equivalent series capacitance of the winding increases, and the potential distribution of the winding when the lightning impulse voltage penetrates improves and the lightning impulse voltage It is possible to construct a winding with high dielectric strength.

[0006]

Recently, in order to reduce the eddy current loss generated in the winding conductor in the winding, the conductors are insulated from each other having a small cross-sectional area as shown in FIGS. A transposed cable in which a plurality of strands 3 are bundled and treated as one conducting wire is often used. In order to reduce the difference in the interlinkage magnetic flux of the wires having a small cross-sectional area, the transition cable 1 is formed by transferring the cable wires 3 as shown in FIG. However, due to the transition of the strands, the cross section AA in FIG. 7 is a plane in which two transposed cable strands 3 are lined up on one side in the stacking direction as shown in FIG. Only one strand 3 is protruding. Section B- of a part a little away from the section A-A
In B, as shown in FIG. 9, the dislocation cable strands 3 are projected at both ends in the stacking direction, and the strands themselves are inclined to minimize the space in the dislocation cable 1.

When the rectangular shield conductor 5 is wound around the winding of the unit cable 1 having such a cross section, the transposed cable 1 and the shield conductor of the rectangular wire 5 are only partially adhered to each other. In the case of oil insulation, oil with a relative permittivity of approximately 2.3 enters this gap, which does not differ much from the relative permittivity of the cable paper covering the winding, which is approximately 3.3. The capacitance of the shield conductor can be increased to some extent. However, in the case of gas insulation, a gas having a relative permittivity of 1 enters the gap between the transposed cable and the shield conductor of a rectangular wire, which is much smaller than that of a polymer film having a relative permittivity of about 3 for the cable. For this reason, the capacitance of the winding of the transposed cable and the shield conductor of the rectangular wire is dominated by the capacitance of the contacted portion, and the capacitance of the winding wire of the rectangular wire and the shield conductor of the rectangular wire are used. It was much smaller than the capacitance, and the effect of increasing the series capacitance of the winding was small. For this reason, the increase in series capacitance due to the effect of the shield conductor becomes small. Therefore, in order to obtain a desired series capacitance, it is necessary to lengthen the winding length of the shield conductor, which lowers the space factor. Moreover, the number of man-hours was also increased.

Therefore, an object of the present invention is to provide a gas-insulated induction device in which the series capacitance of the winding is increased by increasing the capacitance between the transition cable and the shield conductor.

[0009]

DISCLOSURE OF THE INVENTION The present invention is a gas-insulated induction device using a transition cable composed of a plurality of strands as a winding wound around an iron core. A shield conductor having at least flexibility in the stacking direction of the strands of wire is arranged between the one end surface of the other transposed cable facing the one end surface in the stacking direction, and the transposed cable is press-fitted through the shield conductor. It is characterized by being configured.

[0010]

With the above structure, the opposing surfaces of the transposed cable and the shield conductor are flexibly deformed, and the close contact portion between the opposing surfaces of the transposed cable and the shield conductor is increased. Therefore, the capacitance can be increased, so that it is possible to provide a gas-insulated induction device in which the series capacitance of the winding is increased.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The same parts as those in the conventional configuration are designated by the same reference numerals. In FIG. 1, shield conductors are arranged between the transition cables 1.

That is, the hollow portion 8 of the shield conductor is crushed in conformity with the convex portion of the transposed cable 1 and the shield conductor is deformed, so that the transposed cable and the shield conductor come into close contact with each other. As a result, the capacitance can be increased, so that the series capacitance of the winding can be increased and the dielectric strength against lightning impulse voltage can be improved.

The shield conductor comprises a hollow conductor wire 6 covered with an insulating film 2. 2 to 4 show other configuration examples of the shield conductor. In the configuration shown in FIG. 3, a plurality of cylindrical conductors 7 are arranged side by side and an insulating coating 4 is applied.

By doing so, the cylindrical conductor 7 is deformed and closely adheres to the dislocation cable 1 to increase the capacitance. For this reason, the effect of being able to increase the series capacitance of the winding and to improve the dielectric strength against lightning impulse voltage remains unchanged.

As another configuration example, as shown in FIG. 3, a conductive elastomer 9 such as EP rubber to which carbon having the same shape as the cross section of a rectangular wire is filled with an insulating tube 11 is used as a shield conductor. Even with this,
Since the conductive elastomer 9 is deformed and closely adheres to the dislocation cable 1 to increase the capacitance, the series capacitance of the winding can be increased and the dielectric strength against lightning impulse voltage can be improved. The effect of being able to do it does not change. Furthermore, if the conductive elastomer is thermosetting, the conductive elastomer is hardened by drying and heating after the winding is completed, so that the winding has high mechanical strength.

Further, as shown in FIG. 4, a foamed plastic 12 is placed inside a conductive plastic tube 12, and an insulating film 2 is wound around the foamed plastic 12 as a shield conductor. The effect of being able to increase the series capacitance of the winding and improve the dielectric strength against lightning impulse voltage remains unchanged. The above-described effects can be obtained not only in the gas-insulated transformer but also in the gas-insulated reactor having the same winding structure as the transformer.

[0017]

As described above, according to the present invention, by adopting the flexible structure in which the shield conductor is easily deformed in the stacking direction, the portion where the transition cable and the shield conductor are in close contact with each other is increased, and the transition cable is used. Since the series capacitance of the winding can be easily increased, it is possible to provide a highly reliable gas-insulated induction device having excellent dielectric strength against lightning impulse voltage.

[Brief description of drawings]

FIG. 1 is an exemplary sectional view of a winding structure according to an embodiment of the present invention.

FIG. 2 is a sectional view showing the configuration of a conductive shield according to the present invention.

FIG. 3 is a sectional view showing the configuration of a conductive shield according to the present invention.

FIG. 4 is a sectional view showing the configuration of a conductive shield according to the present invention.

FIG. 5 is a sectional view showing the configuration of a conductive shield according to the present invention.

[Fig. 6] Example solution diagram of dislocation state of dislocation cable

FIG. 7 is a cross-sectional view of the configuration of the transition cable

FIG. 8 is a cross-sectional view of the configuration of the transition cable

[Explanation of symbols]

1 ... Transposed cable 2 ... Insulation film 3 ... Element wire 4 ... Insulation coating 5 ... Rectangular conductor 6 ... Hollow conductor 7 ... Cylindrical conductor 8 ... Hollow part 9 ... Conductive elastomer 10 ... Foamable plastic 11 ... Insulation tube 12 ... Conductive plastic tube 13 ... Winding conductor

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Claims (6)

(57) [Claims] 1. In a gas-insulated induction device using a transition cable composed of a plurality of strands as a winding wound around an iron core, facing one end face of the transition cable in the stacking direction of the strands. A shield conductor having at least flexibility in the stacking direction of the strands is arranged between one side end faces of the other transition cable, and the transition cable is press-fitted via the shield conductor. Gas insulated induction equipment. 2. The gas-insulated induction device according to claim 1, wherein the shield conductor is formed by insulatingly coating an outer cover of a hollow conductor. 3. The gas insulated induction device according to claim 1, wherein the shield conductor is formed by arranging a plurality of cylindrical conductors juxtaposed to each other and integrally insulating-coating them. 4. The gas insulated induction device according to claim 1, wherein the shield conductor is a conductive elastomer coated with an insulating coating. 5. The gas-insulated induction device according to claim 1, wherein the shield conductor is a hollow conductive plastic cable in which foaming plastic is enclosed. 6. The gas insulated induction device according to claim 4, wherein the conductive elastomer is thermosetting.