JPS59186316A - Foil winding transformer - Google Patents

Abstract

PURPOSE:To improve the strength of a winding against the force along the axial direction and strengthen the supporting structure for the winding by fixing insulation sheets by insulation rods attached to a base insulation cylinder. CONSTITUTION:Holes 24, to which insulation rods 22 are attached, are provided to a base insulation cylinder 20. Holes 23, through which the insulation rods 22 are inserted, are provided to the projecting ends 21 of insulation sheets. The insulation rod 22, one end of which is attached to the hole 24, is inserted through the holes 23 provided to the projecting ends 21. The insulation rod 22 and the holes 23 provided to the projecting ends have the same shape and a plurality of their combinations are provided to the winding along the circumference direction. With this constitution, the strength of the winding against the force along the axial direction can be improved and the supporting structure for the winding can be strengthened.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a foil-wound transformer using a foil-like winding made by overlapping and wrapping a metal sheet such as copper or aluminum foil and an insulating sheet, and particularly relates to , relates to improvements in axial fixing means for windings.

Technical background of the invention and its problems] Foil-wound transformers have a good winding space factor and can be made smaller and lighter. Small-capacity transformers with relatively low voltages ranging from several KV to several hundred KV have already been put into practical use. In recent years, in view of its excellent advantages, high N pressure,
Example 1: The expansion of application to 275KV, 300MVA class transformers has been studied, but the biggest technical problem is how to improve the cooling capacity and provide high insulation capacity to the windings. 1) Whether the radial mechanical force at the time of a short circuit accident can cause blood loss or not. Although such high-voltage, large-capacity transformers have not yet been put into practical use, as shown in Figure 1, a cooling duct is built into the windings, and a refrigerant with excellent insulation properties is fed into the cooling duct. A heat pipe-type foil-wound transformer, which uses the latent heat of vaporization of a refrigerant to cool down the heat generated from winding loss, is promising.

That is, in the foil-wound transformer, a basic insulating tube 18 is fitted to the leg l of the iron core, and a metal sheet 2 and an insulating sheet 3 are placed on top of the basic insulating tube 18, and a low-voltage winding 4 and a high-voltage winding each having 0 turns are connected. The wire 5 is wound,
A hollow cooling duct 6 is built inside these windings.
There is. Here, the higher the voltage of the high voltage winding 5 becomes as it is wound outward, the outermost turn is at the 00% position and is connected to a high voltage lead (not shown). On the other hand, in the thin gap in the hollow part of the cooling duct 6, Freon I (-1
A refrigerant such as No. 13 or Fluorinert FC75 is sealed in the refrigerant, and is circulated by a pump 7 to absorb the heat generated within the winding as latent heat of evaporation of the refrigerant, and the vapor is sent to a condenser 8 and cooled by a C cooling water pipe 9 to be condensed. It has become. A cooling system is constructed in which the liquefied refrigerant is stored in a refrigerant tank IO and further fed into the windings by a pump 7.

The liquid guide pipe 11 constituting the cooling system is made of metal such as stainless steel, and the liquid guide pipe 11 and the cooling duct 6 are connected to each other via an insulating pipe 12 made of Teflon resin or the like. This liquid guide pipe is also connected to the ground potential of the tank 13 and the like. On the other hand, since the cooling duct 6 is built into the winding, it is electrically connected to the same potential as the adjacent winding. Historically, the insulation of each part of the winding was done using tank 13.
C is ensured by an insulating gas such as SF6 gas sealed inside.

In addition, since the winding structure of the high voltage winding 5 is one in which a thin gold/i4 sheet 2 and an insulating sheet 3 are stacked and wound in C, the electric field at the end 14 and 15 of the high voltage winding facing the tank 13 is becomes very strict. Therefore, the high voltage winding end L4.
15 is attached with shields 16 and 17 for mitigating the electric field.

The foil-wound transformer described above is generally called a separate foil-wound transformer because the cooling system in which the refrigerant circulates and the insulating gas of the winding are completely separated, but the heat pipe type foil-wound transformer In addition to this, the device also includes a spray set that mixes an insulating medium and a refrigerant in a tank and sprays the refrigerant onto the windings, and a spray set that stores the refrigerant in a container installed in the tank and sprays the windings here. A pool type method in which water is immersed in water is known.

By the way, in the above-mentioned various foil-wound transformers C, since the insulating sheet 3 is wider than the metal sheet 2, the insulating sheet 3 protrudes from the metal sheet 2 at both the upper and lower parts. Since this protrusion is made of a thin insulator, it has no rigidity, so it is impossible for the end face of the insulator to receive mechanical force in the direction of the winding axis. The force and the force between the insulating sheet 3 and the basic insulating cylinder 18 prevent displacement between the sheets and the entire winding.

However, in a structure that receives axial force with more force than this, when the capacity becomes large, C
C is extremely weak against the axial thrust generated between the low-voltage winding 4 and the high-voltage winding 5, and the weight of the winding when it becomes large.
It is unreliable. In a separate foil-wound transformer as shown in Fig. 1, there is still no cooling duct 6 inside the winding.
For those who wear it, the distance between each sheet 2 and 3 deteriorates, making it even weaker against axial forces.

As another means of receiving an axial mechanical force (with a length equal to the protruding length between the sheets of the protruding insulating sheet 3), the insulating sheet 3 is made of the same insulator as the metal sheet 2.
A possible structure is to support this end by aligning the end face of the insulator inserted into the end. However, with this method, it is difficult to match the end face of the insulator that has been pushed toward the end with the end face of the metal sheet 2, so that a slight gap is created between the metal sheet 2 and the insulator. Under mechanical force in the axial direction, the metal sheet 2
When the gap between the metal sheet 2 and the end insulator is crushed, wrinkles occur in the insulating sheet 3, and these wrinkles are caught between the metal sheet 2 and the end insulator, causing the insulating sheet 3 to collapse.
gets hurt. If such a flaw exists at the end of the metal sheet 2 where the electric field is concentrated, it will cause insulation breakdown between the turns. On the other hand, C is not preferable.

OBJECTS OF THE INVENTION The present invention eliminates the above-mentioned conventional drawbacks, and aims to improve the strength of the foil winding against forces in the direction of the winding axis, and to provide a reliable winding support structure having a stable winding support structure. Our objective is to provide high quality foil-wound transformers.

[Summary of the Invention] The foil-wound transformer of the present invention has holes in the protrusion of the insulating sheet in the same radial direction, inserts an insulating rod into the hole, and fixes one end of the insulating sheet to the basic insulation. This structure strengthens the support structure for the windings by improving the strength against forces in the axial direction of the windings.

[Embodiment of the Invention] An embodiment of the present invention will be specifically described below with reference to FIGS. 2 and 3. Components that are the same as those of the conventional type shown in FIG. 1 are designated by the same reference numerals, and their explanation will be omitted.

In the sectional view of FIG. 2, the C high voltage winding 19 is connected to the low voltage winding 4.
The basic insulation tube 20 is arranged between the pressure winding 19 and the saw basic insulation tube 20.
It is wound on top of C, and this basic insulation cylinder 2° contains 1ml.
X24 to which the m-phase constant insulation rod 22 is attached is provided.

The end protrusion 21 of the insulating sheet 3 is provided with a hole 23 into which a fixing insulating rod 22 is inserted. The end protrusion 21 of the insulating sheet 3 has sufficient mechanical strength, and an insulating rod 22 having the same shape as the insulating sheet 3 glue (23) is inserted.
One end of the insulating sheet 3 is fixed to the two-base insulating cylinder 20 so as to support it. A plurality of insulating rods 22 are arranged in the circumferential direction of the winding, and the mechanical force is as shown in the cross-sectional view of Fig. 3. It is most effective to provide the holes 23 in the circumferential direction evenly as shown in FIG.

In the foil-wound transformer of this embodiment having such a configuration, the thrust in the winding axis direction generated in the metal sheet 3 and the dead weight of the winding are absorbed by the insulating rod 22 through the force exerted by the insulating sheet 3. It is possible to prevent the winding from shifting in the axial direction. Furthermore, by fixing the cooling duct 6 to the insulating rod 22, it is possible to prevent the cooling duct 6 from breaking. In addition, since the structure supports the ends of the insulating sheet 3, the insulating sheet 3
Since the distance between the edges 21 and 21 of the sheets can be maintained, creeping discharge due to contact of the sheet edges can be prevented.

Note that the present invention is not limited to the above-described embodiments, and similar effects can be obtained with C in foil-wound transformers other than separate foil-wound transformers. In this example, the present invention is applied only to high-voltage windings, but it can also be applied to low-voltage windings, and is applied to those in which both twisted windings are wound around the same insulating tube. It is also possible. Furthermore, if the insulating rod 22 is applied only to either the upper end or the lower end of the winding, the C
effective.

In the embodiment shown in FIG. 2, the insulating rod 22 is fixed only to the basic insulating tube 20, but in the other embodiment shown in FIG. 4, another insulating tube 25 is provided outside the winding. The other end of the insulating rod 22 is fixed to this insulating cylinder 25. When this configuration is used, it is possible to tighten the entire winding in the radial direction, and when the winding is short-circuited, the short-circuit mechanical force acting as a tensile force C on the outside of the winding can be received by the outer insulating cylinder 25 and the insulating rod 22. This allows the winding to be strong in both the axial and radial directions.

〔Effect of the invention〕

As described above, according to the present invention, the metal sheet is indirectly fixed by fixing the thread insulation reference sheet with the insulating rod, so that the strength of the sheet-like winding against one mechanical force in the axial direction is improved. Therefore, it is possible to provide a highly reliable foil-wound transformer with a stable winding support structure.

Fig. 1 is a sectional view of a conventional foil-wound transformer, Fig. 2 is an enlarged view of the winding portion of an embodiment of the foil-wound transformer of the present invention, and Fig. 3 is a sectional view taken along the line X and -X in FIG. 2, and FIG. 4 is a sectional view showing another embodiment of the present invention.

l...Iron core 2.Metal sheet 3...Insulation sheet 4...Low voltage winding 5...High voltage winding 6
...-Cooling duct 7...Pump 8...Condenser 9...Cooling water pipe 10...Refrigerant tank 11...
-Liquid pipe 12...Insulated pipe ■3...Tank 14.15...High voltage winding end 16, L7
...-Shield 18--Basic insulation part L9...High voltage winding 20...Basic insulation cylinder 21...Insulation sheet protrusion 22...Insulation rod 23...-Hole
24... Hole 25... Insulating tube Agent Patent attorney Noriyuki Chika (1 person) Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] +1) In a foil-wound transformer using a foil winding in which a metal sheet and an insulating sheet are overlapped and wound around a C basic insulating tube, the ends of the C1 insulating sheet protrude in the same radial direction. A foil-wound transformer characterized in that a hole is provided in the hole, a rod-shaped insulating rod having the same cross-section as the hole is inserted into the hole, and one end of the insulating rod is fixed to an insulating cylinder. (2) The foil-wound transformer according to claim 1, wherein the insulating tube is also provided outside the winding, and the other end of the insulating rod is fixed to the outer insulating tube.