JPS6095907A - Foil wound transformer - Google Patents

Abstract

PURPOSE:To enhance the reliability in insulation of the titled transformer by a method wherein both inlet part and outlet part of refrigerant are provided on the same side along the direction of winding axis, and they are arranged in reverse direction each other at the part located between colling panels provided adjoining to the radial direction. CONSTITUTION:A refrigerant inlet part 71 and a refrigerant outlet part 72 are provided on the same side along the direction of winding. Said headers 71 and 72 are provided at the lower part and the upper part of the cooling panels 7. When said cooling panels 7 are going to be arranged on the winding, the direction of the headers are arranged upside down for every adjoining cooling panel in the radial direction of winding. The insulation distance can be made longer by securing sufficient distance between the cooling panels.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a foil-wound transformer in which a metal sheet and an insulating sheet are overlapped to form a winding, and particularly to an improvement in a cooling panel.

[Technical background of the invention and its problems]

Foil-wound transformers are characterized by good winding space and can be made smaller and lighter. It has already been put to practical use in small capacity transformers with relatively low voltages of several KV and several IQQ KVA.

In recent years, in view of its excellent advantages, research has been conducted to expand the application of higher voltage, larger capacity transformers, such as 275 KV and 300 MVA class transformers, but the biggest technical problem is how to improve cooling capacity and The two issues are whether the winding can have insulation ability and whether it can withstand the radial mechanical force in the event of a short circuit accident. Although such high-voltage, large-capacity foil-wound transformers have not yet been put into practical use, as shown in Figure 1, a cooling duct is built into the winding, and a refrigerant with excellent insulation properties is fed into this cooling duct. The most popular type of transformer is the so-called heat-vib type foil-wound transformer, which uses the latent heat of vaporization of a refrigerant to cool the heat generated from winding loss.

That is, in this foil-wound transformer, a low-voltage winding 4 and a high-voltage winding 5 each made of a metal sheet 2 and an insulating sheet 3 wound over each other are wound around a leg 1 of an iron core, and the outermost part of the high-voltage winding 5 is High-voltage shields 6 are disposed at both upper and lower ends. In addition, the low voltage winding 4
A hollow cooling panel 7 extending in the axial direction is built into the high voltage winding 5. In the thin gap in the hollow part of the cooling panel 7, Freon R-113 and Fluorinert F
A refrigerant such as C75 is sealed in the refrigerant, and is circulated by a pump 8 so that the heat generated within the windings is absorbed by the latent heat of evaporation of the refrigerant, and the vapor is cooled and condensed in a condenser 9. A cooling system is constructed in which the liquefied refrigerant is stored in a refrigerant tank 10 and further fed into the windings by a pump 8.

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 panel 7 are connected via an insulating pipe 12 made of Teflon resin or the like. The liquid guide pipe 11 is also connected to the ground W of the tank 13 and the like. On the other hand, since the cooling panel 7 is incorporated into the winding, it is electrically connected to the same potential as the adjacent winding. Furthermore, the insulation of each part of the winding is ensured by an insulating gas such as SF or gas sealed in the tank 13. Further, grounding components 14 are arranged above and below the winding.

By the way, the above-mentioned foil-wound transformer uses a thin metal sheet 2.
By overlapping and winding the insulating sheet 3, the high voltage winding 5
Since the low-voltage winding 4 is formed, there is an advantage that the winding space factor within the core window is increased, but on the other hand, there are the following problems.

That is, in FIG. 3 showing the second factor and the cooling panel in which the end of the high-voltage winding 5 is enlarged, upper and lower headers are provided at the end of the cooling panel 7 to guide the refrigerant from the cooling panel 7 to the outside. 71 and 72 are attached, forming a refrigerant inlet portion 71 and a refrigerant outlet portion 72.

In such a conventional cooling spring /I/7, as shown in FIG. 2, the distance d between the adjacent headers 71 and 72 is short, which poses a major problem in terms of insulation.

In other words, the size of the headers 71 and 72 is limited to a certain size due to the need to flow the entire refrigerant, and it is impossible to make it smaller than that due to the cooling structure. Since it is necessary to attach a shield, there is a problem that the adjacent insulation distance d cannot be set to a sufficient value in terms of insulation.

In order to solve this problem, it is conceivable to arrange the cooling panels 7 so as to be offset from each other in the circumferential direction, but the part from which the refrigerant is drawn out is limited to the outside of the iron core window, and the header 71.
The length of the two parts is relatively long, and the above problem still remains unsolved. Furthermore, in actual transformers, it is necessary to draw out the high voltage leads from the part outside the iron core window, which poses a problem because the header may become an obstruction.

[Purpose of the invention]

The present invention has been made in view of the various problems in the conventional art described above, and it improves insulation reliability by ensuring sufficient distance between cooling headers at the ends of the windings, and provides a foil-wound transformer without any cooling problems. The purpose is to provide equipment.

[Summary of the invention]

The present invention provides a header/portion t of one cooling panel, that is, a refrigerant inlet and outlet can be arranged on the same side along the winding axis direction, and radially adjacent cooling panels can be arranged in the same direction. By placing it in the opposite direction,
A feature is that the distance between the cooling panel headers at the ends of the windings is maintained at a value sufficient for insulation, thereby improving insulation reliability.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. The configuration of the cooling panel 7 of the present invention is shown in FIG.

The refrigerant inlet portion 71 and the refrigerant outlet portion 72 (header) are attached to the same side along the winding axis direction.

The cooling panel main body has the same structure as the conventional one shown in FIG. Although FIG. 4 shows the headers 71 and 72 attached to each other at the bottom, a header in which the headers 71 and 72 are attached to each other at the top is also available. When the cooling panels 7 having such a configuration are arranged in the winding, the headers of the cooling panels adjacent to each other are arranged in the upward direction in the radial direction of the winding, and the cooling panels 7 are arranged as shown in FIG. There is.

In the present invention configured as shown in Fig. 9X45, the distance between the cooling panels can be sufficiently spaced from d in Fig. 2 to Fig. 5, so that insulation reliability can be improved. Furthermore, as shown in Figures 3 and 4, the conventional refrigerant and the refrigerant of the present invention (the two according to the present invention) are completely equivalent in the panel, so the application of the present invention will not reduce the cooling efficiency. No problem.

〔Effect of the invention〕

As explained above, according to the present invention, the insulation reliability of a part of the cooling panel header at the end of the winding can be improved, and a foil-wound transformer with sufficient cooling efficiency can be obtained.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional foil-wound transformer, Figure 2 is an enlarged cross-sectional view of the end of its high-voltage winding, Figure 3 is a front view of a conventional cooling panel, and Figure 4 is a transformer according to the present invention. FIG. 5 is a front view showing the cooling panel, and a sectional view showing the panel arrangement according to the present invention. 1...Iron core 11.Liquid guide pipe 2...Metal sheet 12...Insulation pipe 3...Insulation sheet 13...Tank 4...Low voltage winding 71...Refrigerant inlet header 5.
...High voltage winding 72...Refrigerant outlet header 6...High pressure shield 7...Cooling panel representative Patent attorney Noriyuki Chika (and one other person) Figure 1 Figure 2 7/ Figure 3 7 / Figure 4

Claims (1)

[Claims] In a foil-wound transformer, a metal sheet and an insulating sheet are layered and wound around an iron core, and a cooling panel is inserted inside the sheet with an appropriate gap in the winding direction, through which a refrigerant flows.
A foil characterized in that the refrigerant inlet and outlet of the cooling panel are formed on the same side, and the inlet and outlet of adjacent cooling panels are arranged in opposite directions in the winding stack direction. winding transformer.